Sustainable Structures
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- Old residual mortar as a quality indicator of recycled brick aggregate
- Sustainable Structures Vol.4,No.3,2024 DOI:10.54113/j.sust.2024.000061 Online published:2024-12-1
- Abstract Old residual mortar (RM) on recycled aggregate surfaces is a major factor contributing to its lower quality. The present study aims to quantify the effect of old mortar on the properties of recycled brick aggregates (RBA) and recycled concrete (ReC) made with them. The process involves collecting and crushing discarded concrete blocks from seven sources to create recycled brick aggregates. A chemical-thermal combined process removes old mortar, and with varying RM contents, the aggregate properties are determined. C-25-grade concrete specimens are prepared using RBA with different RM content and tested for workability, compressive strength, splitting tensile strength, flexural strength, water absorption, bulk density, and voids in hardened concrete. Regression models expressing the change in properties with RM content are presented. The study reveals that the quality of RBA and concrete worsens with increasing RM, with a 20% RM value being considered a limiting value to maintain minimal variation in properties. The regression models suggest that every 10% increase in RM may result in an 11% increase in water absorption of RBA, an 8% increase in aggregate crushing value (ACV), a 3.6% increase in Los Angeles (LA) value, a 10% loss in compressive strength of ReC, a 7% loss in tensile strength, and a 9% loss in flexural strength, approximately. The developed models may be used to predict the expected quality of RBA and ReC based on their attached old RM, which would be helpful in deciding their usage for different applications.… More
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- Behaviour of post-tensioned benches made of high-content recycled aggregate concrete reinforced with racquet string fibres
- Sustainable Structures Vol.4,No.3,2024 DOI:10.54113/j.sust.2024.000060 Online published:2024-12-1
- Abstract This study investigates the serviceability and structural behaviour of a new type of recycled aggregate concrete (RAC) bench with waste badminton racquet fibres. Twenty-one cantilever benches were tested in two Series with different fibre volume fractions (Vf = 0%, 0.5%, 1.0% or 1.5%). The RAC had 100% of natural aggregates replaced with recycled concrete aggregate (RCA). The benches in Series II were post-tensioned in flexure using an innovative Post-Tensioned Metal Strapping (PTMS) technique using 1, 2 or 3 straps. Tests were carried out to evaluate 1) static loading behaviour, 2) long-term behaviour after 365 days of sustained loading, and 3) human-induced vibrations. The static test results show that benches with 100% RAC and PTMS had higher capacity (by about 25%) that counterpart benches without PTMS. Hence, the maximum flexural strength of the cantilever bench was improved by 5.7% for the cantilever bench with PTMS strengthening, which further enhanced the flexural behaviour compared to the bench with only 1.5% of fibres. The human-induced vibration test results confirmed that the maximum vibration of the benches met the code limits for floor buildings. Finite element analyses of the RAC benches with PTMS were carried out in Abaqus®, and the experimental deflections agreed well (errors <5%) with the FEM results. A simplified fatigue life analysis confirmed that the RAC benches with PTMS can have a potential service life of up to 20 years. The use of glow-in-the-dark (GID) features into the benches in Series II enhanced their night-time visibility and visual appeal by up to 8 h. This research contributes towards the development of new applications for RAC with waste badminton racquet fibres, which can offer more sustainable solutions for the construction of urban furniture.… More
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- Behaviour and design of extruded high-strength aluminium alloy SHS beam-columns
- Sustainable Structures Vol.4,No.3,2024 DOI:10.54113/j.sust.2024.000059 Online published:2024-12-1
- Abstract An extensive study of beam-columns made from 7A04-T6 aluminum alloy in a square hollow section (SHS) configuration is presented in this paper, integrating both experimental and numerical work to study their flexural buckling behaviour. Eight pin-ended SHS specimens with two extruded SHS profiles - 80×5 and 120 × 10 (in mm), were tested under eccentric compression, along with tests of material coupons and measurements of initial geometric imperfections. The experimental data were employed in the investigation to assess the validity of the numerical model, which was subsequently subjected to a series of parametric analyses aimed at expanding the existing results across a wider spectrum of slenderness ratios, cross-section dimensions, and load combinations. Both experimental and simulated datasets were employed to verify the precision of resistance forecasts for SHS beam-columns by design approaches outlined in European, Chinese and American standards. Findings indicated that both the European and Chinese standards tended to provide relatively conservative predictions for buckling resistances, while the American standard sometimes produced predictions leading to higher risk. Finally, a modification strategy for the design of AA7A04-T6 SHS beam-columns, utilizing modified interaction buckling factors that account for non-dimensional member slenderness and compression resistances, was suggested to enhance the precision and reliability of resistance forecasts.… More
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- Reinforcing the brittle resistance of high-strength concrete using agricultural waste fiber
- Sustainable Structures Vol.4,No.3,2024 DOI:10.54113/j.sust.2024.000058 Online published:2024-12-1
- Abstract The utilization of natural fiber wastes could be an ideal way to tackle two problems. Firstly, this may be a solution to the issue of environmental challenges related to agricultural wastes. Secondly, it can potentially fix high-strength concrete's (HSC) issue of unexpected (sudden) collapse. This study looked at the results of using two different kinds of natural fiber waste in HSC. Seven HSC mixtures were manufactured; three included rice straw fibers (RSF), three contained palm leaf sheath fibers (PLSF), and one was a control mix (without fibers). In this research, the volume fractions of RSF and PLSF ranged from 1% to 3% and had an aspect ratio equal to 100. Different tests, including slump test, compressive strength, modulus of elasticity, flexural strength and tensile strength were conducted to determine their various properties. There were no significant improvements on compressive strength due to use of natural fiber while its tensile and flexural strengths increased particularly when including 1% RSF. RSF improved the properties of HSC more significantly than PLSF.… More
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- An assessment of the pozzolanic potential and mechanical properties of Nigerian calcined clays for sustainable ternary cement blends
- Sustainable Structures Vol.4,No.3,2024 DOI:10.54113/j.sust.2024.000057 Online published:2024-12-1
- Abstract This study investigates the potential of calcined clays from Nigerian deposits as supplementary cementitious materials. Clay materials were obtained from three sites namely: Ikpeshi, Okpilla and Uzebba. The raw clay samples were then calcined at 700°C and 800°C. Chemical and mineralogical compositions were determined for the raw and calcined clay samples using XRF and XRD respectively. The chemical composition by XRF confirmed these clays as potential pozzolans with SiO2, Al2O3, and Fe2O3 collectively exceeding 70%. XRD analysis identified kaolinite and quartz as major mineral phases in the raw clays, which transformed into metakaolin upon calcination. Thermo Gravimetric Analysis (TGA) indicated varying lime consumption levels among the clays, with Ikpeshi clay displaying the highest pozzolanic reactivity and Uzebba clay the least. Compressive strength investigation on mortar cubes prepared with 50% substitution of Portland cement with the calcined clay and limestone, showed that Ikpeshi clay at 800°C had the best strength performance, with strength activity index of 0.92 (at age 28 days), demonstrating superior pozzolanic potential. Strength development was more significant between 7 and 28 days, indicating the pozzolanic reaction's contribution to long-term strength. However, initial strength at 3 days was lower than the reference Portland cement due to a delayed pozzolanic reaction. XRD analysis of blended pastes revealed typical phases of hydration like portlandite, calcium silicate hydrate phase, strätlingite, and ettringite, with the calcined clay blends showing reduced portlandite content, indicating absorption by the pozzolan's alumina phase.… More
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- Evaluating suitability of regression models in small data regimes using concrete with recycled copper tailings as a case study
- Sustainable Structures Vol.4,No.3,2024 DOI:10.54113/j.sust.2024.000056 Online published:2024-12-1
- Abstract The utilization of regression models for the prediction of construction material properties is well-established, yet their performance when applied to small datasets is still unclear. This study investigates the performance of different regression models combined with various data preprocessing techniques in contexts where data is limited. Specifically, the research focuses on evaluating the suitability of five regression models across nine different data processing scenarios using concrete with recycled copper tailing as a case study. This study aims to determine which combinations of regression models and preprocessing methods yield the most accurate predictions in small data regimes. This research is motivated by the necessity to enhance prediction reliability in the field of construction materials, where experimental data can often be scarce or costly to obtain. Within the study context, a dataset comprising 21 experimental specimens is used to evaluate the performance of the models on various concrete properties, including fresh density, compressive strength, flexural strength, pull-off strength, abrasion resistance, water penetration, rapid chloride ion permeability, and air permeability. Through rigorous evaluation involving a 10-fold cross-validation process to verify accuracy, the research demonstrates that selecting the optimal regression model and data preprocessing technique selection substantially improves prediction outcomes, even with limited data. The findings highlight the importance of this research, suggesting that even small datasets, when handled correctly, can provide robust insights.… More
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- Mechanical response of glass/kevlar hybrid composite jackets for steel containers carrying hazardous materials to enhance safety
- Sustainable Structures Vol.4,No.3,2024 DOI:10.54113/j.sust.2024.000055 Online published:2024-12-1
- Abstract Fiber reinforced (FRP) composite materials have high strength-to-weight ratios and excellent corrosion resistance. Cost reduction manufacturing through methods like Vacuum Assisted Resin Transfer Molding (VARTM) is impressive. This paper deals with composite materials reinforcement of railway tank cars via VARTM to enhance safety, improve fuel efficiency, and reduce adverse environmental impact during derailments aligning with industry goals for safer, sustainable solutions in relation to new railway tank car safety standards. This study investigates different performance aspects of various fiber/fabric configurations (glass, aramid) used as reinforcement with vinyl ester or epoxy. Additionally, core materials like polyurethane and polypropylene have been researched to enhance energy absorption. Effects of through-thickness stitching on mechanical integrity are evaluated for improved puncture resistance. Testing revealed that Kevlar fibers increased energy absorption by increasing strain to failure. Epoxy resin lowered maximum tensile strength by 22% compared to vinyl ester and increased the total energy absorption by 8%. Through-thickness stitching (z-direction) increased tensile strength by 13% and improved interlaminar shear strength.… More
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- Structural performance of additive manufactured wood-sodium silicate composite beams for sustainable construction
- Sustainable Structures Vol.4,No.3,2024 DOI:10.54113/j.sust.2024.000054 Online published:2024-12-1
- Abstract The current research examines the structural bending performance of additive manufactured wood-sodium silicate composite beams of various span-to-height proportions. Beams consisting of both a single layer as well as two layers of extruded wood-sodium silicate composite were considered. Both groups of beams exhibited a rise in maximum shear force (Vmax), maximum bending moment (Mmax), apparent modulus of elasticity (MOEapp), and modulus of rupture (MOR) when the span-to-height proportions rose. However, the amount of shear stress (τmax) decreased as the span-to-height proportion increased. Furthermore, the flexural and shear stress patterns for span-to-height proportions of 6 and 30 were calculated analytically using the transformed section methodology across the thickness of the beams at different positions of L/6, L/3, 5L/12, and L/2 of the beam span. The results demonstrated that the bending stress increased as the distances from the supports increased toward the middle of the beam. Compared to single-layer beams, two-layer beams displayed lower stress values overall. In particular, the bending stress was 4.85% lower in the two-layer beam with a span-to-height proportion of 6 than that of the single-layer beams. Furthermore, the single-layer beam's maximum shear stress was slightly greater than the two-layer beams. The greatest shear stress of the single-layer beams were computed 4.27% and 0.46% higher than those of the two-layer beams at span-to-height proportions of 6 and 30, respectively.… More
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- Experimental evaluation on the axial crushing performance of BFRP-bamboo winding composite hollow components
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000053 Online published:2024-9-7
- Abstract In order to study the quasi-static axial crushing performance of BFRP-bamboo winding composite hollow components, considering the cloth ratio of BFRP (0%~14.68%) the number of BFRP layers (0 layer~4 layers) as an influencing factor, 20 tube specimens were designed for quasi-static compression tests. In this paper, the failure modes of the specimens under quasi-static axial compressive load are presented with the relevant load-displacement curves. The deformation types were carefully studied to evaluate the compressive crushing indicators of the specimens. The test results showed that when the cloth ratio of BFRP increased from 0 to 14.68%, the specific energy absorption (SEA), the mean crushing force (MCF) and the crushing load efficiency (CFE) increased to some extent, whilst the initial peak crushing force (PCF) did not show any trend. When compared with those of the bamboo winding hollow components (BT), the SEA, MCF and CFE of BFRP-bamboo winding composite hollow components with four layers of BFRP winding outside of BT (BBT4) increased by 87.53%, 194.37% and 255.59% respectively. Compared with other composite hollow components such as composite wrapped hollow components (CWT) and carbon reinforced composite hollow components (CRCT), BFRP-bamboo winding composite hollow components (BBT) showed superior crushing resistance while offering the advantages of light weight.… More
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- The influence of nucleus dates waste and ceramic wastes in sustainable concrete
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000048 Online published:2024-9-4
- Abstract Recycling has progressed recently, turning specific non-renewable resources into renewable ones. This has led to a considerable increase in research on using waste materials such as ceramic and nucleus date waste as alternative aggregate materials in buildings. They suggest using aggregate from nucleus dates rubbish and ceramic waste to reduce the amount of waste in the environment and address material shortages at building sites. This study was aimed at determining whether the incorporation of ceramic waste aggregates (CWA) and nucleus dates aggregate (NDA) instead of coarse aggregate can improve strength ultra-high-performance concrete (SHPC) properties. Ten SEC combinations were prepared: 10%, 20%, and 30% of NDA, CWA, or a combination of both. After testing, quartz powder (Q.P) or silica fume (S.F.) can increase the UHPC by enhancing its mechanical characteristics. Waste as construction materials could have substantial technological, economic, and environmental advantages when employed within a sustainable development framework. The study's conclusions proved that replacing NDA or CWA can improve the qualities of SHPC, especially when replacing 10% of the original material.… More
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- Life cycle assessment and mechanical strength of cement composites with conventional, and recycled fine aggregate
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000052 Online published:2024-9-3
- Abstract Generally, sand as a filler material in the concrete composite is mined from the riverbed, which is the primary source of the entailed fine aggregate to keep pace with the emergent demand for concrete production. Unbridled sand extraction from the riverbed and the river bank has detrimental impacts on the environment and river geomorphology. On the other hand, construction and demolition sites generate a significant amount of solid waste, which contains fine aggregate. This study aims to explore the applicability of recycled fine aggregate (RFA) in comparison to coarse sand and fine sand in cement composites, considering their compressive strength, financial aspect, and environmental sustainability by means of Life Cycle Assessment (LCA). Hence, 12 (twelve) different combinations of the aforementioned fine aggregates were taken into consideration to determine the extent of using RFA as a replacement for conventional fine aggregates, signifying the motivation of the study. In this study, the crushing strength of cement mortars at different curing ages was compared. At 28 days, mortar with 100% coarse sand showed 25% higher, and mortar with 100% fine sand showed 67% lower compressive strength than the mortar with 100% RFA. The mix combination of 25% RFA and 75% coarse sand produced the cement mortar with a maximum compressive strength of 48.25 MPa. From LCA, subsuming the waste product (RFA) into cement composite exhibited the lowest environmental impact, in contrast to those made with natural sand. Considering the physical properties of fine aggregates, and the crushing strength of mortar along with environmental and economic aspects, cement mortar with RFA can be an environmentally sustainable option and an approach to reduce construction waste and expenses.… More
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- Flexural behavior of high-strength reinforced concrete beam with hybrid fiber under normal and high temperature
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000051 Online published:2024-9-3
- Abstract The low cost of basalt and steel fibers makes their use in enhancing concrete properties very attractive, this paper presents experimental research on the use of Basalt Fibers (BF) and Steel Fibers (SF) and their effect on compressive, tensile, and flexural behavior of reinforced concrete beams under normal and elevated temperatures. Nineteen beams, 114 cubes, and 114 cylinders were tested to find the optimum percentage of fibers. The percentages of BF used were 1%, 2%, and 3.5% by cement weight, while the percentages of SF were 0%, 0.5%, 1%, and 1.5%. Heated samples were subjected to 600 ℃ for 3 hours and left to cool off naturally before testing. The test results show that using BF and SF significantly increased the tensile strength of unheated cylinders, with the optimum fiber content of 1% BF - 1.5% SF achieving an increase of 163% over the control. For heated cylinders, the optimum fiber content was (2% BF - 1.5% SF) achieving an increase of 175%. For compressive strength, enhancement was more modest for most of the fiber content ratios used, and the optimum mix of (1% BF - 1% SF) achieved an enhancement for unheated and heated conditions of 27% and 44%, respectively. Flexural results show that beams employing a mix of 2% BF and 1% SF yielded the most favorable result at normal temperature, enhancing the capacity by 27% compared to the control. While at high temperatures, using an optimum mix of 1% BF and 1.5% SF achieved a 27.2% increase compared to control. The use of BF and SF in concrete has also been proven to increase the ductility of the beams and has moved the failure mode from shear to flexural failure.… More
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- Integration of fly ash and ground granulated blast furnace slag into palm oil fuel ash based geopolymer concrete: a review
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000050 Online published:2024-9-3
- Abstract The construction industry significantly depends on concrete due to its mechanical attributes and economy efficiency. The increase demand for building materials, particularly concrete, has resulted in overproduction of ordinary portland cement (OPC) and consequent significant release of carbon dioxide (CO2) into the atmosphere. For addressing these issues, alternative innovative and sustainable materials, such as geopolymer concrete, which utilised waste materials as binding agents have been introduced, leading to a reduction in CO2 emissions. Palm oil fuel ash (POFA) contains abundant silicates and aluminates, making it well-suited for use as binder in geopolymer concrete. On the other hand, POFA geopolymer concrete with high volume exhibits reduced early strength development, decreased workability, and an extended setting time. Therefore, this review paper emphasizes the need of including fly ash (FA) and ground granulated blast furnace slag (GGBS) into POFA-based geopolymer concrete. A notable result of the review is that the inclusion of aluminium oxide and iron(III) oxide in FA improves the chloride binding capability, resulting to a dense microstructure with high strength. In addition, the presence of calcium oxide in FA and GGBS enhances the creation of C-S-H, N-A-S-H, and C-A-S-H gels, resulting in a decrease in porosity and an enhancement of the fresh and mechanical characteristics. Furthermore, the use of FA improves the insulation and thermal efficiency of the geopolymer concrete. Therefore, integration of FA and GGBS in POFA geopolymer may enhanced the mechanical and durability qualities. Further study is required to optimize the composition of POFA, FA and GGBS in the mix, and researching new, cost-effective alkaline activators obtained from waste products offers another avenue for boosting the efficiency of geopolymer synthesis.… More
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- A new constitutive model for recycled aggregate concrete cylinders actively confined with post-tensioned metal straps
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000049 Online published:2024-9-3
- Abstract The compressive strength of cylindrical columns of recycled aggregate concrete (RAC) is lower than that of equivalent normal concrete columns. Active confinement can recover some of such lower compressive strength, but limited research has examined the stress-strain behaviour of RAC cylinders with active confinement. This study proposes a new constitutive model for RAC cylinders actively confined with post-tensioned metal straps (PTMS). Using pneumatic tools, the PTMS technique involves applying a post-tensioning force to high-strength metal straps. RAC cylinders (⌀150×300 mm) with different confinement ratios (ρv = 0, 0.35, 0.52, 0.80 or 1.6) were subjected to axial compression tests to determine their maximum strength and axial strains. The RAC was produced using recycled concrete aggregate (RCA) as coarse aggregate, considering three compressive strengths: 15, 21 and 24 MPa. The test results indicate significant increases in strength and axial strains as the confinement ratio increased, with the strength improving by 29% to 196% and peak axial strains by 90% to 158% across ρv values from 0.35 to 1.6. Based on the test results and a regression analysis, a new stress-strain constitutive model is proposed to assess the effectiveness of the PTMS confinement. The results of this study promote the use of RAC in construction by demonstrating that the mechanical properties of RAC structural members can be effectively enhanced through the PTMS technique.… More
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- Design and construction of houses with Guadua cane and rice husk in Ecuador as an alternative to local development
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000047 Online published:2024-9-3
- Abstract The use of sustainable construction materials as a response to habitat problems is one of the urgent alternatives for Ecuador. The country has a high production of rice, an intensive crop that generates a high volume of polluting waste that is not efficiently managed, which causes damage to the environment. The purpose of the research was the design and construction of a construction system with the joint use of Guadua cane, of ancestral domain, and rice husk as components of a hybrid lightweight concrete. As a result, two houses were built in 1992 and 2020, respectively, validating the feasibility of the proposal. A flexible, resistant, sustainable system is achieved, which takes advantage of local resources, both traditional and alternative, that allow to give an answer to the habitat with a good aesthetic finish. It is an alternative for the local development of autonomous governments that allows the construction of decent, durable and comfortable housing, with the use of their own resources and in accordance with the country's traditions.… More
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- Investigating crack growth in two-dimensional plates with openings using the peri-dynamic method
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000046 Online published:2024-9-3
- Abstract Analyzing and simulating the growth of dynamic cracks in the shell of structures and two-dimensional plates is one of the important topics for providing solutions to prevent crack growth and sudden failures, which increases the lifespan of the structure. Despite many studies by researchers regarding the behavior of structures against crack growth and sudden failure, there are still many problems regarding the analysis and simulation of the mechanical behavior of shells and plates with openings. Therefore, the peri-dynamic method can be directly used to model crack growth in these types of structures. In this research, modeling of dynamic crack growth as well as factors affecting crack growth and branching in the shell of structures (with and without openings) were investigated using the peri-dynamic method in LAMMPS software. Then the results obtained from the pre-dynamic method were verified with the results of other methods. The comparison of different results showed that the peri-dynamics method is capable of properly modeling crack growth in plates and shells with openings, and in other words, this theory can predict the path of crack growth with high accuracy. According to the obtained results, it can be stated that the process of crack growth and branching in the shell of structures depends on values such as the applied stress, the type of material and the direction of the fibers in the composites, as well as the absence of openings in the shell, which by changing these factors, the speed and The path of crack growth in the body of the structure changes.… More
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- Effect of short basalt fibers on energy-dissipating properties of lightweight rubberized concrete shear wall
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000045 Online published:2024-9-3
- Abstract To enhance the dynamic performance of shear walls, fine-grained rubberized basalt fiber concrete has been proposed as an alternative to conventional concrete. This is a promising material, yet the existing literature lacks an in-depth analysis of its energy dissipation properties. A comprehensive study was performed of fine-grained 100 x 100 mm cylindrical rubberized concrete specimens, both with and without basalt fibers, under low-cycle compression fatigue. The first concrete mixture had a volume fraction of 10 % crumb rubber, and the second concrete mixture contained a volume fraction of 0.3 % basalt fiber in addition to 10% crumb rubber. Scanning electron microscopy and computer tomography were used to validate the material's inner structure, adhesion, crumb rubber and basalt fiber distribution. To acquire the mechanical and dynamic properties of the material, hysteresis loops were obtained from 1000 cycles of compression fatigue tests under 0.1 and 0.05 strain rates on a servo-hydraulic machine through quasi-static laboratory tests. The obtained concrete properties were incorporated into VUMAT plasticity model of concrete and imported to ABAQUS for seismic analysis of reinforced concrete shear walls. A cyclic pushover analysis of the shear wall has been conducted to characterize its hysteretic behavior and energy dissipation for two consecutive concrete series, predicting long-term seismic performance. The concrete series with basalt fiber exhibited higher seismic resilience with hysteretic damping of 9.3% compared to 8.7% for the series without basalt fibers.… More
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- Development and performance evaluation of sustainable lightweight geopolymer based fireproofing coatings for steel construction
- Sustainable Structures Vol.4,No.2,2024 DOI:10.54113/j.sust.2024.000044 Online published:2024-9-3
- Abstract This study developed a novel, sustainable, lightweight, and high-ductility fireproofing coating using granulated blast furnace slag (GBFS), fly ash microspheres (FAC), alkali activator, and polyethylene (PE) fiber as raw materials. The critical mixing ratios of FAC to GBFS (4:6), the water-to-binder ratio (0.55), and the alkali activator modulus (1.4) were determined to meet the requirements for fluidity, compressive strength, and flexural strength. The residual strength and thermal stability of the sample were evaluated through high-temperature exposure tests. The compressive strength results showed that even at 900℃, the lightweight geopolymer-based fireproofing coating exhibited 23 MPa as compared to that of 61 MPa at room temperature, which is 30% of its room temperature strength. X-ray diffraction and scanning electron microscopy were carried out to examine the micro-morphology of the samples, revealing that the main component of the geopolymer was Ca2(Al2SiO7) in a colloidal state at 30℃, 300℃, and 600℃. The reduction in strength at this temperature range was mainly attributed to the surface crack extension. However, at 900℃, the gelatinous Ca2(Al2SiO7) underwent dehydration and transformed into crystalline Ca2(Al2SiO7), or zeolite. The interface bond performance between the fireproofing coating and the steel plate was thoroughly tested through direct shear and normal bond tests, using five different bonding techniques, as well as a tensile test on the fire-resistant material coated steel plate. The bond strength from direct shear test ranged from 0.05 MPa to 1.64 MPa and for normal shear test, the strength was in the range of 0.07 MPa to 1.43 MPa. The results of tensile strength test showed that the coating had high ductility and was fire-resistant, and it could deform synergistically with the steel plate, with a maximum tensile strain of 4%. These results demonstrate the coating's excellent deformation performance.… More
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- Application case of laminated bamboo lumber structure – Building of Sentai Bamboo Research Center
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000043 Online published:2024-6-1
- Abstract Laminated bamboo lumber (LBL) is an engineered bamboo product that provides consistent and reliable mechanical properties for structural applications while offering options for green, environmentally friendly and sustainable development. This paper presents a significant and novel case study highlighting different phases such as analysis, design and construction of a three story office building in which LBL has been used as the main building material. In this building, the main components are prefabricated and then assembled on site making the construction process fast and efficient. Hand calculation techniques were combined with finite element modeling to accurately and efficiently determine the dimensions of components. At present, the design of engineered bamboo structures is based on the standards of wooden structures, but with the gradual increase of engineered bamboo structures, it is important to develop design standards for engineered bamboo.… More
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- Thermal insulation performance of non-load-bearing light gauge slotted steel stud walls
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000042 Online published:2024-5-31
- Abstract Light gauge steel stud walls have been widely used in buildings as load-bearing members. But if used as non-load-bearing walls, more rows of perforations can be placed on stud webs and then the thermal bridge effect can be reduced. Experiments on six non-load-bearing light gauge slotted steel stud walls were conducted using a calibrated hot box. The temperatures of the steel studs and gypsum plasterboard were monitored for subsequent analysis of thermal bridging. The effects of parameters (number of rows of perforations, stud web height, and the ratio of window area to wall area) on the insulating capacity of the wall were identified and analyzed. Thermal transmittance decreases by 18.5% and 29.6% for specimens with 3 and 7 rows of perforations in comparison with the specimen without perforations, while it decreases by 29.8% and 42.7% respectively for 150 mm and 200 mm thick walls compared with that of the 100 mm thick wall. However, thermal transmittance increases obviously for the wall with a window opening relative to the wall without a window opening, reaching 14.7% in this test since more studs are placed around the window opening. A three-dimensional finite element (FE) model of the wall was developed and validated against experimental results, and then was used for parametric studies. A general method of calculating the thermal transmittance of the light gauge slotted steel stud wall was suggested based on the experiment and the FE model results, which can consider influences of wall thickness, web perforations, window openings, and thermal properties of materials.… More
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- Experimental, theoretical and numerical study on the shear stress of adhesive layer in FRP-bamboo scrimber composite beams
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000041 Online published:2024-5-31
- Abstract The adhesive layer is an important factor affecting the mechanical properties of FRP- bamboo scrimber composite beams (FBSCB). However, studies on the interfacial shear stresses in the adhesive layers with both ends of FRP and bamboo scrimber beam aligned have been rarely reported. To this end, a two-parameter theoretical calculation model and a finite element model (FEM) based on cohesive zone model were hereby established to solve for the adhesive layer interface shear stresses, which was verified by four-point bending experiments. The results show that both the two-parameter theoretical model and the FEM can effectively compute the shear stress of the adhesive layer. Meanwhile, the FEM simulation results not only reflect the detailed changes of the shear stress, but also provide a better analysis of the shear stress at the adhesive layer with a small fluctuation range. There are three zones of shear stress at the adhesive layer of FBSCB under four-point bending load, i.e., the bending and shearing zone, the transition zone and the pure bending zone. In the bending and shearing zone, the shear stress of the adhesive layer interface increases 2.61 times and 2.5 times, respectively when the thickness and elastic modulus of FRP increase three times. However, the stress remains constant at zero in the pure bending zone.… More
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- Study on the Permeability and Mechanical Properties of Sandy Soil Under Carbon Fiber-Based Urease Mineralization
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000040 Online published:2024-5-31
- Abstract In recent years, soil solidification by EICP method is a green and environmentally friendly foundation treatment technology that has become popular in the field of geotechnical engineering. Compared with the traditional chemical induction method and the MICP method, the EICP method is not easily restricted by environmental factors associated with engineering geological problems and is green and environmentally friendly with lower cost. In this paper, a study was carried out to improve the seepage-mechanical properties of sandy soils by the EICP method. First, soybean urease solution extraction and its performance optimization methods were explored. Tests were conducted to compare urease extraction and detect activity. The activity of urease was 7.1% higher in deionized water than Laoshan mineral water. Second, the EICP grouting mineralization test was performed by using the carbon fiber reinforcement method. The CaCO3 content, unconfined compressive strength, porosity, permeability and other indicators of the sandy soil were systematically analyzed, and microscopic tests were conducted. The test results showed that after carbon fibers were added to the sand, the mineralization effect of EICP led to the precipitation of CaCO3 that adhered to the surfaces of sand grains and fibers and filled and cemented the pores between sand grains, which improved the integrity of the spatial structure and formed a stable solid sand-fiber monolithic composite structure. When the carbon fiber content was 1.2%, all aspects of performance were optimum. The above test results showed that the carbon fiber-based EICP mineralization method could effectively inhibit the brittle failure and improve the permeability and mechanical properties of sandy soil. This method has good application prospects and development potential for use in engineering geology.… More
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- Effects of aluminum alloy constitutive models on the behavior of concrete-filled aluminum tubular stub columns under axial compression
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000039 Online published:2024-5-31
- Abstract This study aims to examine the effects of various aluminum alloy constitutive models on the behavior of concrete-filled aluminum tubular stub columns under axial compression. The bi-linear model with hardening, the Baehre model, and the Ramberg-Osgood (R-O) model, which follow the European standard (EC9) were analyzed and compared in terms of their ability to describe the stress-strain behavior of aluminum alloy tensile coupons over the full range, and their respective application scenarios were discussed. A total of 74 sets of experimental data results were collected to examine the effects of these three models on the ultimate load of concrete-filled aluminum tubular stub columns. Furthermore, a full-scale model was constructed to analyze the effect of the hardening exponent n in the R-O model on the load-displacement curves. The results show that, apart from the bi-linear model with hardening, the other two aluminum alloy constitutive models are capable of accurately predicting the stress-strain behavior of aluminum alloys throughout the full range. The accuracy of the R-O model is significantly influenced by the calculation methods of n. The Baehre model is found to be more suitable for non-heat-treated aluminum alloys. The simulated ultimate load values obtained from the three constitutive models fall within a deviation range of ±10%, indicating their suitability for practical engineering applications. Among the three models, the R-O model exhibits the highest stability, as changes in the hardening exponent n do not affect the ultimate load but have a significant effect on the load-displacement curves beyond the ultimate load.… More
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- Bond behavior of CFRP-strengthened steel structures and its environmental influence factors: a critical review
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000038 Online published:2024-5-31
- Abstract Adhesively bonded carbon fiber-reinforced polymer (CFRP) systems have shown great promise for strengthening damaged steel structures, offering potential enhancements in the longevity of steel structures. However, the degradation of bond performance of CFRP under harsh environments remains a critical concern for researchers and engineers, as it may significantly impact the efficiency and durability of bonded CFRP strengthening systems. This paper presents a comprehensive review of the impact of key characteristics of bonded joints, such as the CFRP modulus, adhesive performance, bond length, adhesive layer thickness, and bond joint geometry, on the bonding performance of CFRP strengthening systems. Additionally, the influences of environmental factors, including elevated and sub-zero temperatures, moisture, corrosion, humidity, wet-dry cycles, ultraviolet radiation, and freeze-thaw cycles on the bond behavior, were also reviewed. By synthesizing and analyzing existing research insights into the effects of reinforcement materials, bond joint design parameters, and environmental factors on bonding performance, this review article attempts to enhance practitioners' understanding of bond behavior in this field and also provides guidance for future research.… More
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- Progress on the connection performance of steel-engineered bamboo beam-column connections under cyclic loads: a review
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000037 Online published:2024-5-31
- Abstract Bamboo is a great building material due to its low carbon and environmental friendless. The connection performance of beam-column joints had an impact on the seismic performance of the whole structure. The beam-column connection performance is critical in earthquakes. Steel-engineered timber connections have good seismic properties, and the properties of bamboo and timber are very similar. Therefore, the form of wood structure connection can be used in bamboo structures. The type of member materials used and the connection forms applied determine the structure elastic behavior. Common engineered bamboo has been introduced, and the current connection form of engineered timber has been summarized in this paper. Secondly, research on the indicators of connection performance under cyclic loads has been introduced, including damage forms, strength, ductility, and energy dissipation capacity. Thirdly, the traits of various types of connections are presented, and this paper could be taken as a reference for future studies on connections in steel-engineered bamboo structures.… More
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- A logical retrofit strategy optimization framework for resiliency bridge infrastructure management considering life-cycle cost
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000036 Online published:2024-5-27
- Abstract Bridges play an important role in providing essential services to communities as one of the most critical components of transportation infrastructure. In this regard, selecting reliable, robust, and efficient indicators is necessary to prepare a disaster management strategy. This study presents a multi-objective optimization framework for decision-makers to find the most optimal retrofit strategies that satisfy a given threshold of functionality/Resilience (R) while minimizing a structure's Life-Cycle Cost (LCC). Accordingly, various retrofit strategies include different materials (steel, Carbon Fiber Reinforced Polymer (CFRP), and Glass Fiber Reinforced Polymer (GFRP)), thicknesses, arrangements, and timing of retrofitting actions. In each scenario, the fragility curves are derived through nonlinear time-history Incremental Dynamic Analysis (IDA) to evaluate the LCC and resilience. In the subsequent step, the LCC analysis is conducted, considering the proposed formulation of multiple occurrences of seismic events, which incorporates the effects of complete/incomplete repair actions of damage conditions induced by previous seismic events. This study employs an elitist Non-dominated Sorting Genetic Algorithm II (NSGA-II) to identify the optimal set of solutions. The various aspects of the optimal retrofit strategies are thoroughly investigated and discussed for a bridge as a case study infrastructure. Results show that the considered objectives lead to reasonable and sense-making retrofit strategies.… More
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- State-of-the-art review on steel-concrete composite walls
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000035 Online published:2024-5-27
- Abstract Steel-concrete composite walls, valued for their capacity to combine the strengths of steel and concrete, have become a prevalent construction choice. During the past few decades, the performance of steel-concrete composite walls has been studied by means of structural tests, theoretical analysis, and numerical simulation. Different types of steel-concrete composite walls have been proposed by researchers to satisfy miscellaneous structural requirements. Meanwhile, new forms were continually being developed to further improve the mechanical performance. This review paper examines research conducted over the past few years on these versatile structural elements. The paper categorizes steel-concrete composite walls according to the arrangement of steel plates and concrete, along with the configurations of steel plates. It delves into the unique characteristics of each type and analyzes their performance under various loading conditions, including axial, cyclic, shear, fire, dynamic, impact, and joint loads. Additionally, existing design recommendations for these walls are summarized. To conclude, the paper offers insights into potential future developments in steel-concrete composite wall technology.… More
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- Comparison of using two LCA software programs to assess the environmental impacts of two institutional buildings
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000034 Online published:2024-5-27
- Abstract The current trends in climate change have captured the attention of stakeholders across multiple industries, including the building sector. With the introduction of innovative building materials such as mass timber products (MTPs), it has become essential to evaluate their environmental performance. In response, a variety of life cycle assessment (LCA) software programs are available to meet this need. However, it is crucial to understand how different LCA software and databases might influence the results. This study was aimed at exploring the impact of two widely used LCA software programs, SimaPro and Athena Impact Estimator, on LCA results. Two buildings were employed to conduct this study, a traditional institutional building and a mass timber building currently under construction. By comparing the numerical outputs from both software programs, it was discovered that while both could reach similar conclusions regarding the environmental impacts of a building, their use is limited to comparative purposes only. The software programs produced distinct numerical values in their outputs and attributed the sources of impacts differently, indicating they cannot be used interchangeably. However, either SimaPro or Athena Impact Estimator was suitable for estimating the global warming potential of a building during stages A1 to A3.… More
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- “Bamboo: A Very Sustainable Construction Material & the 3rd World Symposium on Sustainable Bio-Composite Materials and Structures” - 2022 International Conference summary report
- Sustainable Structures Vol.3,No.2,2023 DOI:10.54113/j.sust.2023.000033 Online published:2023-11-11
- Abstract The 2022 International Conference—Bamboo: A Very Sustainable Construction Material & the 3rd World Symposium on Sustainable Bio-Composite Materials and Structures—was held from November 8 to December 13, 2022. This conference was led by INBAR and INBAR Bamboo Construction Task Force and co-organized by 37 other national and international institutions. More than 80 experts from over 20 countries delivered speeches or presentations to approximately 1400 participants from 81 countries and shared the latest research and development on bamboo and timber construction with them. The conference convened global architects, engineers, forestry experts, researchers, entrepreneurs, and policy makers to present the potential uses and suitability of bamboo, timber, and other biomaterials as conventional construction materials in modern society. This paper summarizes the key deliberations and findings of the diverse research, including the state-of-practice and the means of moving the state-of-the-art forward. Further actions on training, standardization, and research were urged to be taken to promote this industry.… More
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- Deformation and energy dissipation of steel box girders of cable-stayed bridges subjected to blast loadings
- Sustainable Structures Vol.3,No.2,2023 DOI:10.54113/j.sust.2023.000032 Online published:2023-10-15
- Abstract Steel box girders are widely used in cable-stayed bridges, while they are prone to severe damage under explosions. This paper investigates the deformation and energy dissipation of steel box girder of cable-stayed bridges under blast impact, caused by the accidental explosions of tanker trucks and vehicles. In this study, Hypermesh and LS-DYNA are employed to simulate the dynamic responses of a real steel box girder cable-stayed bridge under explosions. The deformation response and energy absorption of the box girder under explosions are investigated. Several failure modes and failure processes are analyzed and summarized. The findings indicate that the failure mode of an orthotropic steel bridge panel under blast impact is primarily local damage, with the damage process being divided into three stages: local plate deformation, fragment formation, and petal formation. For bridge deck explosions, the main energy dissipation components of steel girders are the bridge panel, web, diaphragm and rib stiffeners. The research results can provide the basis for the follow-up study on the anti-explosion safety of bridge structures.… More
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- Analysis of ultimate fracture bearing capacity of CHS XK-joints welds
- Sustainable Structures Vol.3,No.2,2023 DOI:10.54113/j.sust.2023.000031 Online published:2023-8-14
- Abstract The current study presents advanced finite element (FE) models that combine the stress weighted damage model and the crack propagation using explicit dynamic approach of commercial FE software ABAQUS. The applicability of the subroutine for ductile fracture prediction and crack propagation modeling of structural steel is confirmed by comparing the results of fracture tests performed on circumferential notch specimens. FE analysis is performed on 17 circular hollow section (CHS) XK-joint models with various sized partial penetration welds to simulate the fracture process of the joint models, and the obtained results are used to analyze the fracture ultimate bearing capacity of the joint weld. The results indicate that the crack first appears on the inner side of the weld at the crown point of the intersecting line of the tensile web member. The findings also demonstrate that the joint weld does not lose the bearing capacity completely after the initial cracking. Instead, the joint weld's bearing capacity increased with the displacement at the early stages of fracture propagation to reach the maximum value prior to gradual decrease in bearing capacity. A design formula of weld bearing capacity suitable for partial penetration weld has been proposed herein to incorporate the effects of uneven distribution of joint weld stress in the considered XK-joints.… More
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- Design and construction of “Bamboo Cubic” facade with laminated bamboo lumber
- Sustainable Structures Vol.3,No.2,2023 DOI:10.54113/j.sust.2023.000030 Online published:2023-7-3
- Abstract This paper presents the design and construction of the facade renovation project ("Bamboo Cubic" project) of Huangqiao Square in Shaowu City, Fujian Province, China. In this project, the structural form and cross-sectional dimensions were determined using a combination of manual and finite element analysis to meet relevant regulations. Once the structural form was confirmed, primary structural components such as the foundation, the column base, and the connection between frame elements were designed to comply with design requirements. Innovative connections were used to install a unique curved design, which required curved LBL members to be prefabricated with precision. The total height of the LBL bamboo frame part is 16.86 m. This project clearly showed that engineered bamboo can be used both as a structural primary member as well as for aesthetic purpose. Use of steel and LBL frames in the "Bamboo Cubic" facade project highlighted the prospect of future hybrid construction.… More
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- Failure Behavior and Failure Locations of Oxytenanthera Abyssinica Bamboo Culms under Bending Load
- Sustainable Structures Vol.3,No.2,2023 DOI:10.54113/j.sust.2023.000029 Online published:2023-7-3
- Abstract Bending failure modes in solid stem wood and solid culm bamboo varies depending on material and geometric properties. Solid culm cross-sections of Oxythenantera Abyssinica round bamboo resemble to wood, but are anatomically different in their mode of growth and tissue organization. The bending stress gradient and failure behavior has highly related with the culm internal voids termed as hollowness which depends on age of bamboo. Hollowness (k) refers the relative proportion of void volume to solid volume with in a culm. Full culm beam specimens with length of 3.5 m were subjected to bending under 4-point static loading according to ISO 22155. Pattern of vertical deflection varies depending on the maturity of the culm. A statistical and experimental results showed that, for K values between 12-15% a mixed mode of local buckling with a longitudinal shear splitting failure mode was resulted in 4-year age bamboo specimens with a slight (14 mm) shift from the shear center inducing large vertical deflection (142 mm) at midspan. A kink buckle and green stick modes were observed in 2-year and 3-year ages culms at failure point of 124 and 158mm at length ‘L’ (L/2.5 to L/4.5) from shear center with a k value 25-27% and 18-22% respectively.… More
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- Fatigue behavior and calculation methods of high strength steel fiber reinforced concrete beam
- Sustainable Structures Vol.3,No.2,2023 DOI:10.54113/j.sust.2023.000028 Online published:2023-7-3
- Abstract Adding steel fibers into concrete was considered as one of the most effective ways to restrain the crack development and improve the stiffness for reinforced concrete (RC) structures. To explore the reinforcement mechanism of steel fibers on the fatigue behavior of high-strength RC beam, eight high-strength steel fiber reinforced concrete (HSSFRC) beams subjected to fatigue loading were tested in this study. The main design parameters considered in this work were stress level and steel fiber content. The failure mode, crack patterns, fatigue life, crack width, and stiffness degradation of HSSFRC beams under fatigue loading were discussed. The results showed that steel fibers could significantly increase the fatigue life, restrain crack development, and improve crack patterns of HSSFRC beams under fatigue loading compared to ordinary RC beams. Both the crack width and stiffness degradation rate of beams decrease with increasing steel fiber content. Besides, the empirical formulas for calculating the maximum crack width and midspan deflection of HSSFRC beam under fatigue loading were proposed and validated using experimental results.… More
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- Experimental research on formaldehyde emission characteristics from glubam by climate chamber test
- Sustainable Structures Vol.3,No.2,2023 DOI:10.54113/j.sust.2023.000027 Online published:2023-7-3
- Abstract Glued laminated bamboo (glubam) is a type of bamboo-based lamina, and manufactured by pressure lamination of phenol-formaldehyde saturated bamboo strips under elevated temperature. Estimating, controlling, and limiting the formaldehyde release from glubam are important issues in indoor air quality of building with glubam. This study investigates formaldehyde emission characteristics from two types of glubam under different conditions including temperature, relative humidity, edge treatment, and surface covering material. A series of formaldehyde concentration tests were performed using 1 m3 climate chamber. The results indicate that the peak values of the formaldehyde concentration of glubam specimens under all testing conditions are lower than 0.124 mg/m3, and thus can be classified as Class E1 according to EN 13986. An analysis model was provided to estimate formaldehyde release based on the test data and a first-order decay model. Initial formaldehyde emission rate E0 and decay rate constant k in the proposed model was utilized for comparison and analysis of the experimental parameters. This investigation reveals that the temperature and relative humidity have significant influence on the formaldehyde emission characteristics of glubam boards. Sealing cutting edges and covering surface layer of the samples can significantly reduce the releasing rate and amount of formaldehyde from glubam.… More
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- Assessment of physical and mechanical properties of juvenile and matured Bambusa vulgaris glue-laminated bamboo for structural applications in Ghana
- Sustainable Structures Vol.3,No.2,2023 DOI:10.54113/j.sust.2023.000026 Online published:2023-7-3
- Abstract This study assessed the properties of juvenile and matured glue-laminated bamboo for structural applications. Glue-laminated bamboo was produced from 2-year-old and 4-year-old culms of Bambusa vulgaris with a fast-curing polyurethane adhesive (Rapid Lion). The composites produced were assessed for their physical (moisture content, basic density, radial, longitudinal, tangential and volumetric shrinkage) and mechanical (modulus of rupture, modulus of elasticity and compressive strength parallel to grain) properties. The results show that the juvenile glue-laminated bamboo significantly shrinks about twice that of the matured glue-laminated bamboo with values of 6.32% for radial, 6.51% for tangential and 0.22% for longitudinal. It was further observed that the basic density of the matured glue-laminated bamboo was 810.56 kg/m3 which is 14.56% higher than that of the juvenile glue-laminated bamboo. The juvenile glue-laminated bamboo had MOE of 5876 MPa; MOR of 43.42 MPa and compressive strength of 37.58 MPa whilst that of the matured glue-laminated bamboo recorded MOE of 13379 MPa; MOR of 82.48 MPa and compressive strength of 62.78 MPa. The matured bamboo laminates had better physical and mechanical properties than that of the juvenile bamboo laminates. It is recommended that matured Bambusa vulgaris can be used as an engineered composite material for structural applications.… More
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- Structural responses of FRP sheet piles under cantilever loading
- Sustainable Structures Vol.3,No.1,2023 DOI:10.54113/j.sust.2023.000021 Online published:2023-6-1
- Abstract Sheet piles are interlocked segments used for temporary or permanent soil and water retaining structures such as below-grade parking structures and sea walls. Although steel is commonly used due to its strength and ease of manufacturing, it rusts in saltwater. Fiber reinforced polymer (FRP) composite sheet piles are resistant to chlorides and have higher corrosion resistance, but their mechanical properties vary in length and width. Stress risers at corrugation corners make soil-structure interaction a challenging design issue. This research aims to develop a standardized test procedure to determine the resisting moment capacity of FRP composite sheet piles. Cantilevered FRP sheet piles fixed with a sand-concrete mixture of ~70 psi (0.48 MPa) compressive strength were tested under static loads. Strain gages and LVDTs were used to collect data on deformation response up to and beyond peak induced stress. Results suggest that the refined test procedure can assist engineers in designing efficient sheet pile structures and become a basis to develop ASTM standard.… More
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- Lightweight bamboo structures - Report on 2021 International Collaboration on Bamboo Construction
- Sustainable Structures Vol.3,No.1,2023 DOI:10.54113/j.sust.2023.000025 Online published:2023-6-1
- Abstract 2021 International Collaboration on Bamboo Construction was held from September 1 to December 1, 2021. The practice was held by the College of Civil Engineering of Nanjing Forestry University, University College London, International Bamboo and Rattan Organisation (INBAR) and co-organized by 6 international institutions and national companies of China. Two main bamboo structures were setup by the teachers and students in the campus of Nanjing Forestry University. More than 50 students attended the practice, including international students from different countries. The practice was held to deliver the feasibility and applicability of bamboo in various geometries and different spans, and different areas. Innovative technologies like BIM Revit Architecture and Sketchup were used for the design of bamboo structures. The main principle of the practice was that the raising of bamboo structures should be simple using a minimum of materials aside from bamboo. The results of the project contributed to the popularization of the use of bamboo in the architecture, engineering and construction sectors.… More
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- The effect of including biomass on the rheological and pozzolanic properties of Portland limestone cement- case study
- Sustainable Structures Vol.3,No.1,2023 DOI:10.54113/j.sust.2023.000024 Online published:2023-6-1
- Abstract Various investigations have been presented on the possibility of using agro-allied industry waste in concrete, with the goal of achieving a cleaner environment and environmentally friendly construction. Biomass fly ash (BFA) and limestone clinker are waste from steam/power plants and the cement industry, respectively, and are of high relevance to economic and environmental problems. The effect of including biomass on the rheological and pozzolanic properties of Portland limestone cement (PLC) pastes are presented. The BFA was used as partial replacement for PLC as supplementary cementitious materials (SCMs). The rheological properties (yield stress, viscosity and thixotropy) of the cement paste were determined using a parallel-plate rotational rheometer. The pozzolanic properties were determined using thermogravimetric analysis (TGA) by measuring the amount of calcium hydroxide (CH), and calcium silicate hydrate (CSH) of the hydrated paste, as well as the reaction kinetics. Different characterization techniques including X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and scanning electron microscopy (SEM) were used to study the microstructure and mineralogy of the BFA. It was observed that the mineral composition of the biomass fly ash is like class C fly ash. At 15% of cement replacement the paste exhibits better rheological properties: lower yield stress and lower viscosity up till 120 min after mixing, which is an important factor in ready-mix concrete plants. However, a better pozzolanic behavior was observed at 20% cement replacement. From the results obtained, the properties of the paste containing BFA is very sensitive to water/binder ratio (w/b). Above 20% cement replacement, it is suggested to use viscosity modifying agent (VMA) to get a better rheology and pozzolanic behavior.… More
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- I-shaped ECC/UHPC composite beams reinforced with steel bars and BFRP sheets
- Sustainable Structures Vol.3,No.1,2023 DOI:10.54113/j.sust.2023.000022 Online published:2023-6-1
- Abstract This paper proposes a new type of small-sized I-shaped engineered cementitious composite (ECC)/ ultra-high performance concrete (UHPC) composite beam which has the potential to be suitable for corrosive environments. The lower tensile part of the beam was made of ECC material (2/3 of the height), and the top compressive part was made of UHPC material (1/3 of the height). Inner embedded steel bars and surface-bonded basalt fiber reinforced polymer (BFRP) sheets were adopted as the reinforcing materials in combination. A total of nine I-shaped beams were designed and tested under four-point bending test. The influence of parameters such as the ratio of the embedded tensile steel bars, the top UHPC flange, and the surface bonded tensile BFRP sheet on the behavior of the beams was investigated. The results showed that the I-shaped ECC/UHPC composite beams have excellent comprehensive performance, and thanks to the ultra-high durability of the component materials, they have ultra-high durability that ordinary I-steel beams do not have and thus have broad application prospects in corrosive environments. The shear resistance capacity of the thin-walled ECC web needs to be further improved, and UHPC is recommended for the web in the follow-up study.… More
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- Structural analysis of a Guadua bamboo bridge in Colombia
- Sustainable Structures Vol.2,No.2,2022 DOI:10.54113/j.sust.2022.000020 Online published:2022-12-1
- Abstract In recent years, scientists have focused their attention in developing sustainable materials that can boost the construction industry without causing damage to the environment. In South and Central American forests grows a tropical species of bamboo known as guadua angustifolia Kunth, which has been widely used for construction purposes since ancient times. Offering advantages such as: environmental friendliness, fast-growing and high strength-to-weight ratio. This paper analyzes the structural behavior of an existing multi-culm guadua bamboo truss type footbridge located in Colombia, according to national regulations NSR-10. A model of the structure is implemented using a commercial finite element software, details for an accurate description of the structure’s behavior through the proposed model are offered. Furthermore, an exhaustive description of the structure’s load transfer and its materials mechanical properties is performed, as well as a review on connections and immunization process. Finally, improvement opportunities for the building codes used for the analysis and investigation opportunities are identified. The purpose of this paper is stepping into the right direction thus, one day guadua angustifolia Kunth and bamboo in general can be fully exploited in the construction industry.… More
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- State-of-the-art review on the use of lignocellulosic biomass in cementitious materials
- Sustainable Structures Vol.3,No.1,2023 DOI:10.54113/j.sust.2023.000023 Online published:2023-6-1
- Abstract The lignocellulosic biomass wastes cause some burden on the environment; meanwhile, the concrete industry is faced with large amounts of carbon dioxide emissions and raw mineral materials consumption. The use of lignocellulosic biomass wastes in cementitious materials not only provides an alternative to deal with the wastes but also favors the sustainable development of concrete industry. This review first introduces the characteristics of lignocellulosic biomass and then examines its effect on the mechanical properties, shrinkage, cracking, and some other properties of cement composites. Results show that lignocellulosic biomass can be directly used for three purposes: reinforcements, aggregates, and cement replacements. Although the lignocellulosic biomass cannot always enhance the mechanical properties of cementitious materials, it can improve toughness, shrinkage, cracking, heat insulation, etc. Additionally, some concerns with the use of lignocellulosic biomass are summarized, for which some physical and chemical modification methods (heating treatment, boiling treatment, torrefaction treatment, etc.) are identified to change the structure or remove amorphous components of lignocellulose biomass or prevent it from directly contacting cementitious materials. This review can provide some guidance for designing sustainable cementitious materials with lignocellulosic biomass.… More
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- Influence of stacking sequence on mechanical properties and moisture absorption of epoxy-based woven flax and basalt fabric hybrid composites
- Sustainable Structures Vol.2,No.2,2022 DOI:10.54113/j.sust.2022.000016 Online published:2022-12-1
- Abstract Hybrid composite laminates (HCL) were prepared by lay-up molding using a hot-press bed for reinforcing epoxy-based woven flax and basalt fabric composites. Mechanical properties and moisture absorption of HCL were measured, and the fracture surface was examined by scanning electron microscopy (SEM). The present results indicated that the mechanical properties of HCL are strongly dependent on the sequence of fiber reinforcement. HCL (S2, S3, S4, S5) with symmetric stacking sequences that increase with basalt fibers (wt %) showed a positive hybridization effect on mechanical properties and curve characteristics. However, the mechanical properties of S7 (asymmetric stacking) were lower than S3, S4, S5 (symmetric stacking), which indicated that symmetric stacking sequences of HCL had superior mechanical performance compared with the cross arrangement of HCL. The moisture absorption of HCL samples immersed in water at 26 °C showed the Fickian behaviour up to 42 days and were not affected by altering the stacking sequence on HCL. The SEM of the fracture surface, fiber-matrix bonding, and interfacial bonding of flax-basalt fabric HCL were also presented.… More
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- Structural response of high strength concrete beams using fiber reinforced polymers under reversed cyclic loading
- Sustainable Structures Vol.2,No.2,2022 DOI:10.54113/j.sust.2022.000018 Online published:2022-12-1
- Abstract This paper investigates the response of high strength concrete (HSC) beams subjected to reversed cyclic loading using carbon fiber-reinforced polymer (CFRP), glass fiber-reinforced polymers (GFRP), and hybrid FRP/steel bars as bottom tensile reinforcement. Five HSC beams with a rectangular cross-section were prepared and cast using concrete with a 28-day compressive strength of 60 MPa (8.7 ksi). A displacement-controlled reversed cyclic loading has been applied to all the beams. The test setup has been designed to simulate the forces and boundary conditions that could happen during seismic action. Flexural capacity, concrete and reinforcement steel strains, cracking behavior, and ductility results were obtained. The hybrid steel/FRP has shown an improved performance in terms of flexural capacity, strains, and ductility. While the inclusion of FRP grids reduces the flexural capacity, this can be improved by adding more layers of FRP. The hybrid reinforced sections showed an increase in moment capacity and ductility compared to the FRP only reinforced beams. The mechanistic model predicted values using code ACI 318 and 60% of the given FRP tensile strength were in good agreement with the experimental results. For the hybrid reinforced beams, moment capacities calculated using ACI 440R was shown to be over-estimated. Although ACI 440R designs for externally wrapped FRP, the sectional analysis was performed with the same process as ACI 318.… More
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- Mechanical properties of timber-concrete connections with steel tube connectors
- Sustainable Structures Vol.2,No.2,2022 DOI:10.54113/j.sust.2022.000017 Online published:2022-12-1
- Abstract Composite connections are important components of timber-concrete hybrid systems. This work presents a novel shear connector for timber-concrete composite (TCC) connections. To verify the composite action between the timber and concrete in the proposed connection, ten specimens were subjected to push-out tests to examine the slip at the interlayer. The failure mode and maximum load capacity results are analyzed, indicating that the composite connections have good ductility and high load capacity. Four methods to determine the yield point are compared and discussed in detail. According to the test results, a mathematical model is utilized to predict the nonlinear load-slip curve of the proposed connection. The Bayesian method is introduced to estimate the model parameters and quantify the model uncertainty. The obtained results can be used for further reliability analysis. This work demonstrates that timber-concrete connections with novel connectors perform well and show potential for application in composite structures.… More
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- Analysis of the mass and deformation variation rates over time and their influence on long-term durability for specimens of porous material
- Sustainable Structures Vol.2,No.1,2022 DOI:10.54113/j.sust.2022.000014 Online published:2022-6-1
- Abstract In an environment subjected to continuous climatic evolution, the study of the long-term behavior of building materials subject to environmental aggressions becomes an extremely important factor in evaluating the sustainability of these materials over time. The damage due to the aggression of external agents does not only affect the surface of the building but can cause a loss of performance in the mechanical qualities of the material with the worsening of the safety conditions of the entire structure. The velocity of the damage evolution is an interesting item. Here the variation velocity of some parameters characterizing the porous materials subjected to aggressive actions is dealt with. Starting from standard material characterization tests, extending the test times, the rate of variation of the mass and the deformation induced by the absorption of saline solutions in the porous medium and the variation of these speeds over time were evaluated. Hypotheses are formulated on the influence that this speed on the degradation of the material in the short and long time. The results obtained show how long-term aggressive action can cause internal damage with a consequent critical increase in absorption, mass and deformation, phenomena that can induce even severe damage to structural elements.… More
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- Parametric design of developable structure based on Yoshimura origami pattern
- Sustainable Structures Vol.2,No.2,2022 DOI:10.54113/j.sust.2022.000019 Online published:2022-12-1
- Abstract Origami is an ancient art form and can be divided into rigid and non-rigid origami. Rigid origami is suitable for the design of building structures because the panels are not twisted and deformed during the folding process. Currently, rigid origami structures are generally built with steel. However, compared with natural, non-polluting wood, steel has a high energy consumption and a high environmental impact. Based on this situation, this paper designs a developable wooden building structure using the Yoshimura origami model. First, the Jacobian matrix method was used to analyze the degree of freedom of the basic unit of the Yoshimura origami pattern, following which the motion trajectory required by the target structure was obtained. Secondly, by analyzing the relationship between the plane angle α and dihedral angle θ, three interaction rules were obtained, and the formula for determining the structure size was established by using the plane angle α, dihedral angle θ, the number of valley folds n and the unit length l. Subsequently, two enhancement schemes, the quadrangle enhancement scheme and the triangle enhancement scheme, were proposed to increase the height of the structure. After comparing the deformation and failure types of origami structures based on Cross-Laminated Timber, a triangular reinforcement scheme was chosen to increase the height of the structure. Finally, a new connection method was developed that allowed the origami structure to be practically applied. This research demonstrates the possibility of developing a timber structure based on Yoshimura origami.… More
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- A review of tiny houses in North America: Market demand
- Sustainable Structures Vol.2,No.1,2022 DOI:10.54113/j.sust.2022.000012 Online published:2022-6-1
- Abstract The history, status quo, and prospect of tiny houses in North America were reviewed. The market demand for tiny houses in North America was analyzed according to the needs in various market segments, such as shelters for low-income and homeless people, recreational housing for vacationers, and the restoration and reconstruction after disasters. This study also discussed timber framed tiny housing communities for retirees, tourism companies offering timber framed tiny housing accommodation, and government-sponsored timber framed tiny housing projects for post-disaster reconstruction. Throughout years of promotion by tiny house enthusiasts, medium advocators, and construction practitioners, more and more people have come to realize the advantages of timber framed tiny houses, such as energy conservation, low carbon footprint, and sustainable development. In summary, the market for timber framed tiny house in North America is in a stage of rapid development, showing a bright future.… More
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- An innovative digital workflow to design, build and manage bamboo structures
- Sustainable Structures Vol.2,No.1,2022 DOI:10.54113/j.sust.2022.000011 Online published:2022-6-1
- Abstract At current rates, the building industry is the major contributor to gas emissions and energy consumption in the world, placing unprecedented pressure to find alternative and sustainable construction materials, particularly in regions where urbanization and population growth are expected to rise. Coincidentally, bamboo culms are a sustainable and abundant resource with the potential to be used as a structural element in those regions, however, their organic nature and inherent incompatibility with modern design and construction procedures have hampered their formal utilization. This article presents the details of an innovative workflow based on the philosophy that the quality and reliability of bamboo structures can be computationally managed through the digitization of individual structural bamboo elements. The workflow relies on reverse-engineering processes that integrate and make bamboo culms compatible with modern data-management platforms such as Building Information Modelling. A case study based on a reconstruction project of bamboo houses in Lombok, Indonesia is presented to illustrate the proposed workflow. This work showed that digitization and management are not just to represent shapes and information regarding bamboo culms through computer software, but can also control the quality, sustainability, and structural behavior of a bamboo structure during its entire service life.… More
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- “Bamboo: A Very Sustainable Construction Material” - 2021 International Online Seminar summary report
- Sustainable Structures Vol.2,No.1,2022 DOI:10.54113/j.sust.2022.000015 Online published:2022-6-1
- Abstract 2021 International Online Seminar - Bamboo: A Very Sustainable Construction Material was held in November 2021. This was led by INBAR and co-organised by other 16 national and international institutions. Nineteen senior experts from 10 countries delivered presentations and shared the latest research and development on bamboo construction to approximately 900 participants from 74 countries. The seminar called upon global architects, engineers and landscape designers to rethink time-tested traditional bamboo architectural forms and related technologies, and use innovative ideas to reshape the global built environment. This paper summarizes the findings of this Seminar, highlighting that while bamboo is growingly accepted as a construction material, considerable efforts are needed to promote bamboo as a mainstream material. The state-of-practice is summarized and means of moving the state-of-the-art forward are discussed. Architects and engineers using bamboo all over the world should work together to contribute to the basic work of bamboo architecture research, standardization and industry development.… More
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- Mechanical behavior analysis of LEM-infilled cold-formed steel walls
- Sustainable Structures Vol.2,No.1,2022 DOI:10.54113/j.sust.2022.000013 Online published:2022-6-1
- Abstract The sustainable development of the engineering structures mainly depends on the environmental- friendly to structural components. This requires the development of sustainable and new materials and structures that would be a worthy alternative for the available. This paper proposed a novel type of cold-formed steel (CFS) shear wall which filling light EPS mortars (LEM) into the space of CFS framing. LEM-infilled CFS walls carry forward the merits of traditional CFS wall, for example lightweight, easy installation, superior earthquake resistance and efficient energy saving. Moreover, employing recycled desulfurization gypsum and EPS in the structural materials reduce environmental pollution. However, the behavior of LEM-infilled CFS wall is not fully explored yet, which results in the low understanding and application of the material around the world. Based on this background, a review of mechanical response tests will contribute to a better awareness. In this paper, three types of mechanical behaviours are discussed including axial compressive behaviour, out-of-plane flexural behaviour, and cyclic behaviour. The previous researches on the mechanical performance of LEM-infilled CFS walls were reviewed. And the typical failure patterns and general results were described and discussed. This work will provide an excellent reference to current practice and future exploration.… More
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- Structural design and construction of an office building with laminated bamboo lumber
- Sustainable Structures Vol.1,No.2,2021 DOI:10.54113/j.sust.2021.000010 Online published:2021-12-1
- Abstract With so many advantages such as environmental friendliness, fast-growing, high strength-to-weight ratio, sustainability, and the capability of being reused or recycled, bamboo structures has gained more and more attention for scientists. This paper shows the feasibility of the design of an office building using laminated bamboo lumbers in compliance with the Chinese standards as GB50009-2012, GB50011-2010, GB50016-2014, and GB 50005-2017. Detailed information about the materials and building were offered. A lot of related construction photos were offered to show the building process. This case is a very good application example for laminated bamboo lumber buildings and has attracted many engineers’ attention in industrial field. Laminated bamboo lumber structures should have a bright future. It should become one main structure form in civil engineering area. However, due to none existing engineered bamboo structures design standard now, engineers have to take reference to standards for timber structures. Setting up the standard system is very important for engineered bamboo structures’ application. Through more and more scientists’ hard working, it might be not a long way to build the code system.… More
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- Review on mechanical behavior of solar cells for building integrated photovoltaics
- Sustainable Structures Vol.1,No.2,2021 DOI:10.54113/j.sust.2021.000009 Online published:2021-12-1
- Abstract The energy crisis and environmental pollution have promoted the rapid development of renewable solar technology. Building integrated photovoltaics (BIPV) is an important field for the future development of solar energy. This review presents the mechanical property studies of existing BIPV and analyzes its research status to offer advice for engineering applications. By analyzing the types and mechanical characteristics of solar cells in the existing BIPV and determining the load conditions that need to be considered in different application modes, this paper summarizes the relevant existing studies at the photovoltaic material, cell and component levels and offers corresponding suggestions for mechanical research, which consequently results in the proposal of a new BIPV structure. Since the mechanical properties of BIPV have seldom been studied, and research on practical engineering applications is lacking, further comprehensive and in-depth research is needed to promote the safe and reliable application and popularization of photovoltaic building integration.… More
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- Development and evaluation of load-bearing fiber reinforced polymer composite panel systems with tongue and groove joints
- Sustainable Structures Vol.1,No.2,2021 DOI:10.54113/j.sust.2021.000008 Online published:2021-12-1
- Abstract This paper focuses on recent advances made in design, development, manufacturing, evaluation and modeling of load bearing fiber reinforced polymer (FRP) composite sandwich panel systems including tongue and groove joints. Several processes have been researched in collaboration with industry partners for production of composite panels, including: 1) pultrusion, 2) high temperature resin spread and infusion, 3) vacuum assisted resin transfer molding (VARTM), and 4) compression molding. The advantages and disadvantages of each process are discussed with emphasis on the high temperature resin infusion process. Composite laminates are characterized in terms of strength and stiffness under tension, bending, and shear in relation to longitudinal and transverse fiber orientations. Thermo-mechanical properties of the FRP composite sandwich panels including joint responses are presented in terms of: 1) the above different processes, 2) carbon fiber versus E-glass fiber, 3) vinyl ester resin versus epoxy resin, and 4) joint design and efficiency. The sandwich panels are evaluated at component and full scales under static four point bending loads and further analyzed using classical finite element models for their mechanical responses.… More
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- Experimental estimation of energy dissipated by multistorey post-tensioned timber framed buildings with anti-seismic dissipative devices
- Sustainable Structures Vol.1,No.2,2021 DOI:10.54113/j.sust.2021.000007 Online published:2021-12-1
- Abstract The need to satisfy high seismic performance of structures and to comply with the latest worldwide policies of environmental sustainability is leading engineers and researchers to higher interest in timber buildings. A post-tensioned timber frame specimen was tested at the structural laboratory of the University of Basilicata in Italy, in three different configurations: i) without dissipation (post-tensioning only-F configuration); ii) with dissipative angles (DF- dissipative rocking configuration) and iii) with dissipative bracing systems (BF - braced frame configuration). The shaking table tests were performed considering a set of spectra-compatible seismic inputs at different seismic intensities. This paper describes the experimental estimation of energy dissipated by multistorey post-tensioned timber prototype frame with different anti-seismic hysteretic dissipative devices used in the DF and BF testing configurations. The main experimental seismic key parameters have also been investigated in all testing configurations.… More
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- 3D printed concrete components and structures: an overview
- Sustainable Structures Vol.1,No.2,2021 DOI:10.54113/j.sust.2021.000006 Online published:2021-12-1
- Abstract This paper aims to present an overview and explore components or structures suitable for 3D printed concrete. Most traditional structural forms are not well suitable for 3D printed concrete. To be more specific, it cannot fully consider the characteristics and advantages of 3D printing such as individualization and digitalization. Several 3D-printing-specific structure forms (including hollow form, tree form, arch form, and structure-functional form) are classified and the relevant successful cases are demonstrated. Moreover, the application potential of 3D printed concrete structures is illustrated and the limitations as well as the solutions for the application of 3D printed concrete in practical projects are also summarized. Based on the classification of different reinforcement materials, several reinforcement methods are intensively discussed for 3D printed concrete including steel bars, fibers and other reinforcement materials. The comparison of economic and environmental benefits between 3D concrete printing technology and traditional construction method is discussed respectively. Finally, the expected evolution of 3D printed structures is put forward and recommended.… More
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- Design issues for smart seismic isolation of structures: past and recent research
- Sustainable Structures Vol.1,No.1,2021 DOI:10.54113/j.sust.2021.000001 Online published:2021-8-1
- Abstract The paper focuses on a number of original researches developed by the authors concerned with the development of new design approaches for smart base isolation systems for structures. Base Isolation (BI) systems represent the first kind of control devices applied to civil structures. In the paper, advancement in technology is exploited in this field, allowing to conceive new BI typologies possibly based on the adoption of special smart materials or on the coupling of the basic passive device with additional corrective devices, in such a way to minimize the disadvantages deriving from the simply passive system.Illustrated procedures also embed in the design pattern of base-isolation systems the interaction effects between structure and soil in order to provide the best tuning of the isolation parameters and to get the maximum performance of the devices, finally summarizing a number of original approaches to design under passive, semi-active and hybrid modes.… More
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- Semi-rigid behaviour of stainless steel beam-to-column bolted connections
- Sustainable Structures Vol.1,No.1,2021 DOI:10.54113/j.sust.2021.000002 Online published:2021-8-1
- Abstract Stainless steel is increasingly used in structural applications but there is still significant lack of experimental evidence on the moment-rotation (M-) behaviour of moment resisting beam-to-column connections. The current paper presents experimental test results obtained from full scale tests conducted on three widely used connection types i.e., double web angle (DWA), top seat angle (TSA) and top seat with double web angle (TS-DWA) connection. Considered beam, column and angle sections were fabricated using austenitic stainless steel plates and M20 high strength bolts were used for connection assembly. M- curves for all connections were carefully recorded and were used to determine initial stiffness (Ki) and moment capacity (M20mrad) for each of the connections. Eurocode 3 guidelines were used to check the classification i.e., whether or not the connections were semi-rigid in nature. Although the considered DWA connection failed to achieve partial-strength, both TSA and TS-DWA connections showed obvious semi-rigid nature despite the connection capacities were limited by bolts. In addition, extensive ductility of stainless steel ensured that all three connection types achieved a minimum connection rotation of 30 mrad, which is specified by FEMA as a requirement for earthquake design of ordinary moment frames.… More
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- Material characterization and structural response under earthquake loads of hakka rammed earth building
- Sustainable Structures Vol.1,No.1,2021 DOI:10.54113/j.sust.2021.000003 Online published:2021-8-1
- Abstract Hakka Tulou are rammed earth buildings that have survived material aging, natural weathering and earthquakes for hundreds of years. Previous paper has reported our observations and findings from nondestructive evaluations in field with focus on the integrity of the rammed earth outer walls and inner timber structures as well as the thermal comfort of living in these buildings. This paper presents the structural response of Tulou buildings under earthquake loads using material data from field and employing finite element (FE) analysis program. The material characterization included scanning electron microscopy and compression strength/modulus of rammed earth samples and wall reinforcements, revealing their high strength and durability. The FE analyses were conducted on unreinforced Huanji Tulou as per the simplified lateral force analysis procedure defined by the Code ASCE-7 under three types of wall conditions: 1) unreinforced rammed earth outer wall only, 2) reinforced rammed earth outer wall without inner wooden structures, and 3) unreinforced rammed earth outer wall with inner wooden structures. The FE modeling revealed that the existing large crack in the outer earth wall of Huanji Tulou would not have developed under a strong earthquake load if the earth walls were reinforced. Furthermore, the high volume rammed earth wall integrated with inner timber structures would have offered the building unique earthquake resistance.… More
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- A review of mechanical behavior of structural laminated bamboo lumber
- Sustainable Structures Vol.1,No.1,2021 DOI:10.54113/j.sust.2021.000004 Online published:2021-8-1
- Abstract The transition of the construction sector to sustainable development mostly depends on the environmental friendliness of building materials. This, in turn, calls for the development of new, strong, and sustainable materials that would be a worthy alternative for traditional materials, including wood. Over the past decade, laminated bamboo lumber (LBL) has received much attention from engineers, practitioners, and scientists for its attractive mechanical properties, comparable to and in some cases superior to hard and softwood. Moreover, the sustainability of LBL is characterized by its high carbon sequestration, fast time to harvest, high yield, and low energy consumption for processing. However, the behavior of LBL is not yet fully understood, which in turn affects the low awareness and application of the material by practitioners and engineers around the world. Since LBL has a promising future, this article will contribute to a better understanding of its mechanical properties and a more accurate design, taking into account the influencing factors. This article discusses the mechanical properties of three types of structural LBL, namely beams, columns, and sheathing panels. The previous works of researchers on the mechanical properties of structural LBL were reviewed, and thus the most common failure modes, the causes of the destruction of structural elements, and the factors that affect their behavior were discussed and described. This work will serve as a reference for current practitioners and future research.… More
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- Research on dynamic characteristics test of wooden floor structure for gymnasium
- Sustainable Structures Vol.1,No.1,2021 DOI:10.54113/j.sust.2021.000005 Online published:2021-8-1
- Abstract In order to better evaluate the structural performance of the wooden floor used in the gymnasium and realize the structural optimization design, this research took the floors of the two gymnasiums in Nanjing as the research object and used the transient excitation method to test the natural frequency and damping ratio parameters of the three types of floor structures, and carried out relevant analysis. The results showed that three kinds of floor structures all meet the requirements of building comfort; under the premise that the types and specifications of the constituent materials were the same, the order of the damping ratios of the three kinds of floor structures from large to small was: fixed floor structure with double-layer load distribution strip, suspended floor structure with single-layer load distribution strip, suspended floor structure with double-layer load distribution strip; compared with the fixed floor structure, the suspended floor structure had low damping ratio characteristics, the energy dissipation of it was slow during structural vibration, which means its impact absorption rate was small, and its impact buffering ability was good, that was, the integral structure had good resilience performance; compared with the floor structure using single-layer load distribution strip, the floor structure using double-layer load distribution strip had a low damping ratio characteristic, the absorption rate of the structure was small and the resilience performance was good. The research conclusion had certain engineering application value.… More
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