Vol.3,No.2,2023-Table of Contents

 

  • “Bamboo: A Very Sustainable Construction Material & the 3rd World Symposium on Sustainable Bio-Composite Materials and Structures” - 2022 International Conference summary report
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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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