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Lateral shear performance of sheathed post-and-beam wooden structures with small panels

《结构与土木工程前沿(英文)》   页码 1117-1131 doi: 10.1007/s11709-023-0939-0

摘要: Sheathed post-and-beam wooden structures are distinct from light-wood structures. They allow for using sheathing panels that are smaller (0.91 m × 1.82 m) than standard-sized panels (1.22 m × 2.44 m or 2.44 m × 2.44 m). Evidence indicates that nail spacing and panel thickness determine the lateral capacity of the wood frame shear walls. To verify the lateral shear performance of wood frame shear walls with smaller panels, we subjected 13 shear walls, measuring 0.91 m in width and 2.925 m in height, to a low-cycle cyclic loading test with three kinds of nail spacing and three panel thicknesses. A nonlinear numerical simulation analysis of the wall was conducted using ABAQUS finite element (FE) software, where a custom nonlinear spring element was used to simulate the sheathing-frame connection. The results indicate that the hysteretic performance of the walls was mainly determined by the hysteretic performance of the sheathing-frame connection. When same nail specifications were adopted, the stiffness and bearing capacity of the walls were inversely related to the nail spacing and directly related to the panel thickness. The shear wall remained in the elastic stage when the drift was 1/250 rad and ductility coefficients were all greater than 2.5, which satisfied the deformation requirements of residential structures. Based on the test and FE analysis results, the shear strength of the post-and-beam wooden structures with sheathed walls was determined.

关键词: post-and-beam wooden structures with sheathed walls     low reversed cyclic loading     bearing capacity     stiffness     numerical simulation    

Self-centring segmental retaining walls—A new construction system for retaining walls

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 980-1000 doi: 10.1007/s11709-021-0737-5

摘要: This paper reports on an experimental study on a new self-centring retaining wall system. Four post-tensioned segmental retaining walls (PSRWs) were experimentally tested. Each of the walls was constructed using seven T-shaped concrete segments with a dry stack. The walls were tested under incrementally increasing cyclic lateral load. The effect of the wall height, levels of post-tensioning (PT) force, and bonded versus unbonded condition of PT reinforcement on the structural behavior of the PSRWs was investigated. The results showed that such PSRWs are structurally adequate for water retaining structures. According to the results, increasing the wall height decreases initial strength but increases the deformation capacity of the wall. The larger deformation capacity and ductility of PSRW make it a suitable structural system for fluctuating loads or deformation, e.g., seawall. It was also found that increasing the PT force increases the wall’s stiffness; however, reduces its ductility. The residual drift and the extent of damage of the unbonded PSRWs were significantly smaller than those of the bonded ones. Results suggest that this newly developed self-centring retaining wall can be a suitable structural system to retain lateral loads. Due to its unique deformation capacity and self-centring behavior, it can potentially be used for seawall application.

关键词: retaining wall     segmental     precast concrete     unbonded post-tensioning     water retaining wall     seawall    

Damage detection in beam-like structures using static shear energy redistribution

《结构与土木工程前沿(英文)》 2022年 第16卷 第12期   页码 1552-1564 doi: 10.1007/s11709-022-0903-4

摘要: In this study, a static shear energy algorithm is presented for the damage assessment of beam-like structures. According to the energy release principle, the strain energy of a damaged element suddenly changes when structural damage occurs. Therefore, the change in the static shear energy is employed to determine the damage locations in beam-like structures. The static shear energy is derived from the spectral factorization of the elementary stiffness matrix and structural deflection variation. The advantage of using shear energy as opposed to total energy is that only a few deflection data points of the beam structure are required during the process of damage identification. Another advantage of the proposed approach is that damage detection can be performed without establishing a structural finite-element model in advance. The proposed technique is first validated using a numerical example with single, multiple, and adjacent damage scenarios. A channel steel beam and rectangular concrete beam are employed as experimental cases to further verify the proposed approach. The results of the simulation and experiment examples indicate that the proposed algorithm provides a simple and effective method for defect localization in beam-like structures.

关键词: damage detection     beam structure     strain energy     static displacement variation     energy damage index    

Parametric study of hexagonal castellated beams in post-tensioned self-centering steel connections

Hassan ABEDI SARVESTANI

《结构与土木工程前沿(英文)》 2019年 第13卷 第5期   页码 1020-1035 doi: 10.1007/s11709-019-0534-6

摘要: The effects of important parameters (beam reinforcing plates, initial post-tensioning, and material properties of steel angles) on the behavior of hexagonal castellated beams in post-tensioned self-centering (PTSC) connections undergone cyclic loading up to 4% lateral drift have been investigated by finite element (FE) analysis using ABAQUS. The PTSC connection is comprised of bolted top and bottom angles as energy dissipaters and steel strands to provide self-centering capacity. The FE analysis has also been validated against the experimental test. The new formulations derived from analytical method has been proposed to predict bending moment of PTSC connections. The web-post buckling in hexagonal castellated beams has been identified as the dominant failure mode when excessive initial post-tensioning force is applied to reach greater bending moment resistance, so it is required to limit the highest initial post-tensioning force to prevent this failure. Furthermore, properties of steel material has been simulated using bilinear elastoplastic modeling with 1.5% strain-hardening which has perfectly matched with the real material of steel angles. It is recommended to avoid using steel angles with high yielding strength since they lead to the yielding of bolt shank. The necessity of reinforcing plates to prevent beam flange from local buckling has been reaffirmed.

关键词: finite element analysis     hexagonal castellated beam     parametric study     post-tensioned self-centering steel connection     steel moment-resisting frame    

Self-centering steel plate shear walls for improving seismic resilience

Patricia M. CLAYTON,Daniel M. DOWDEN,Chao-Hsien LI,Jeffrey W. BERMAN,Michel BRUNEAU,Laura N. LOWES,Keh-Chuan TSAI

《结构与土木工程前沿(英文)》 2016年 第10卷 第3期   页码 283-290 doi: 10.1007/s11709-016-0344-z

摘要: As part of a Network for Earthquake Engineering Simulation research project led by researchers at the University of Washington with collaborators at University at Buffalo, and Taiwan National Center for Research on Earthquake Engineering, a self-centering steel plate shear wall (SC-SPSW) system has been developed to achieve enhanced seismic performance objectives, including recentering. The SC-SPSW consists of thin steel infill panels, referred to as web plates that serve as the primary lateral load-resisting and energy dissipating element of the system. Post-tensioned (PT) beam-to-column connections provide system recentering capabilities. A performance-based design procedure has been developed for the SC-SPSW, and a series of nonlinear response history analyses have been conducted to verify intended seismic performance at multiple hazard levels. Quasi-static subassembly tests, quasi-static and shake table tests of scaled three-story specimens, and pseudo-dynamic tests of two full-scale two-story SC-SPSWs have been conducted. As a culmination of this multi-year, multi-institutional project, this paper will present an overview of the SC-SPSW numerical and experimental research programs. This paper will also discuss innovative PT connection and web plate designs that were investigated to improve constructability, resilience, and seismic performance and that can be applied to other self-centering and steel plate shear wall systems.

关键词: self-centering     steel plate shear walls     large-scale experiment     post-tensioned connections     performance-based design    

Seismic progressive-failure analysis of tall steel structures under beam-removal scenarios

Behrouz BEHNAM, Fahimeh SHOJAEI, Hamid Reza RONAGH

《结构与土木工程前沿(英文)》 2019年 第13卷 第4期   页码 904-917 doi: 10.1007/s11709-019-0525-7

摘要: Investigating progressive collapse of tall structures under beam removal scenarios after earthquake is a complex subject because the earthquake damage acts as an initial condition for the subsequent scenario. An investigation is performed here on a 10 story steel moment resisting structure designed to meet the life safety level of performance when different beam removal scenarios after earthquake are considered. To this end, the structure is first subjected to the design earthquake simulated by Tabas earthquake acceleration. The beam removal scenarios are then considered at different locations assuming that both ends connections of the beam to columns are simultaneously detached from the columns; thus the removed beam falls on the underneath floor with an impact. This imposes considerable loads to the structure leading to a progressive collapse in all the scenarios considered. The results also show that the upper stories are much more vulnerable under such scenarios than the lower stories. Hence, more attention shall be paid to the beam-to-column connections of the upper stories during the process of design and construction.

关键词: progressive collapse     tall steel moment-resisting frames     non-linear dynamic analysis     beam-removal scenario     impact    

Advances in polishing of internal structures on parts made by laser-based powder bed fusion

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0724-0

摘要: The internal structures of metallic products are important in realizing functional applications. Considering the manufacturing of inner structures, laser-based powder bed fusion (L-PBF) is an attractive approach because its layering principle enables the fabrication of parts with customized interior structures. However, the inferior surface quality of L-PBF components hinders its productization progress seriously. In this article, process, basic forms, and applications relevant to L-PBF internal structures are reviewed comprehensively. The causes of poor surface quality and differences in the microstructure and property of the surface features of L-PBF inner structures are presented to provide a perspective of their surface characteristics. Various polishing technologies for L-PBF components with inner structures are presented, whereas their strengths and weaknesses are summarized along with a discussion on the challenges and prospects for improving the interior surface quality of L-PBF parts.

关键词: laser-based powder bed fusion     polishing     internal structures     surface quality     surface features     post process     additive manufacturing    

Damage assessment of laminated composite beam structures using damage locating vector (DLV) method

T. VO-DUY,N. NGUYEN-MINH,H. DANG-TRUNG,A. TRAN-VIET,T. NGUYEN-THOI

《结构与土木工程前沿(英文)》 2015年 第9卷 第4期   页码 457-465 doi: 10.1007/s11709-015-0303-0

摘要: In this paper, the damage locating vector (DLV) method using normalized cumulative energy ( ) is employed to locate multiple damage sites in laminated composite beam structures. Numerical simulations of two laminated composite beams are employed to investigate several damage scenarios in which the degradation of elements is modeled by the reduction in the longitudinal Young’s modulus and transverse Young’s modulus of beam layers. The results show that the DLV method gives good performance for this kind of structure.

关键词: normalized cumulative energy     structural health monitoring (SHM)     damage locating vector method (DLV)     laminated composite beam structure    

Slender reinforced concrete shear walls with high-strength concrete boundary elements

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 138-151 doi: 10.1007/s11709-022-0897-y

摘要: Reinforced concrete structural walls are commonly used for resisting lateral forces in buildings. Owing to the advancements in the field of concrete materials over the past few decades, concrete mixes of high compressive strength, commonly referred to as high-strength concrete (HSC), have been developed. In this study, the effects of strategic placement of HSC on the performance of slender walls were examined. The finite-element model of a conventional normal-strength concrete (NSC) prototype wall was validated using test data available in extant studies. HSC was incorporated in the boundary elements of the wall to compare its performance with that of the conventional wall at different axial loads. Potential reductions in the reinforcement area and size of the boundary elements were investigated. The HSC wall exhibited improved strength and stiffness, and thereby, allowed reduction in the longitudinal reinforcement area and size of the boundary elements for the same strength of the conventional wall. Cold joints resulting from dissimilar concrete pours in the web and boundary elements of the HSC wall were modeled and their impact on behavior of the wall was examined.

关键词: slender walls     high-strength concrete     rectangular and barbell-shaped walls     cold joints    

Behaviour of self-centring shear walls——A state of the art review

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 53-77 doi: 10.1007/s11709-022-0850-0

摘要: The application of unbonded post-tensioning (PT) in structural walls has led to the development of advanced self-centring (rocking) shear wall systems that has significant advantages, including accelerated construction due to the incorporation of prefabricated elements and segmental construction for different materials (e.g., concrete, masonry, and timber), reduced residual drifts, and little damage upon extreme seismic and wind loads. Concrete, masonry, and timber are often used for the construction of unbonded PT structural wall systems. Despite extensive research since the 1980s, there are no well-established design guidelines available on the shear wall configuration with the required energy dissipation system, joint’s locations and acceptance criteria for shear sliding, confinement, seismic performance factors, PT loss, PT force range and residual drifts of shear walls subjected to lateral loads. In this research a comprehensive state-of-the-art literature review was performed on self-centring shear wall system. An extensive study was carried out to collect a database of 100 concrete, masonry, and self-centring shear wall tests from the literature. The established database was then used to review shear walls’ configurations, material, and components to benchmark requirements applicable for design purposes. The behaviour of concrete, masonry and timber shear walls were compared and critically analysed. The general behaviour, force-displacement performance of the walls, ductility, and seismic response factors, were critically reviewed and analysed for different self-centring wall systems to understand the effect of different parameters including configurations of the walls, material used for construction of the wall (concrete, masonry, timber) and axial stress ratio. The outcome of this research can be used to better understand the behaviour of self-centring wall system in order to develop design guidelines for such walls.

关键词: self-centring shear walls     rocking walls     energy dissipation     seismic performance factors     PT loss     residual drift    

Experiment and calculation on seismic behavior of RC composite core walls with concealed steel truss

Wanlin CAO , Weihua CHANG , Changjun ZHAO , Jianwei ZHANG ,

《结构与土木工程前沿(英文)》 2009年 第3卷 第3期   页码 255-261 doi: 10.1007/s11709-009-0043-0

摘要: To improve the seismic performance of reinforced concrete core walls, reinforced concrete composite core walls with concealed steel truss were proposed and systemically investigated. Two 1/6 scale core wall specimens, including a normal reinforced concrete core wall and a reinforced concrete composite core wall with concealed steel truss, were designed. The experimental study on seismic performance under cyclic loading was carried out. The load-carrying capacity, stiffness, ductility, hysteretic behavior and energy dissipation of the core walls were discussed. The test results showed that the seismic performance of core walls is improved greatly by the concealed steel truss. The calculated results were found to agree well with the actual measured ones.

关键词: reinforced concrete     steel truss     core walls     seismic performance    

我国木质林产品质量安全现状及管理对策

崔敏,段新芳,吕斌

《中国工程科学》 2014年 第16卷 第4期   页码 45-50

摘要:

木质林产品是人类生活不可或缺的一类消费品,其产品质量安全与消费者人身安全密切相关。本文主要围绕产品本身质量及产品质量安全管理两个方面分析了目前我国木质林产品的质量安全现状及存在的问题,提出了提高木质林产品质量和保证木质林产品质量安全的对策,以加强我国木质林产品质量安全管理,提高我国木质林产品质量安全水平,促进我国林业产业又好又快发展。

关键词: 木质林产品     质量安全     现状     存在问题     对策    

Seismic effects on reinforcement load and lateral deformation of geosynthetic-reinforced soil walls

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 1001-1015 doi: 10.1007/s11709-021-0734-8

摘要: Current design methods for the internal stability of geosynthetic-reinforced soil (GRS) walls postulate seismic forces as inertial forces, leading to pseudo-static analyses based on active earth pressure theory, which yields unconservative reinforcement loads required for seismic stability. Most seismic analyses are limited to the determination of maximum reinforcement strength. This study aimed to calculate the distribution of the reinforcement load and connection strength required for each layer of the seismic GRS wall. Using the top-down procedure involves all of the possible failure surfaces for the seismic analyses of the GRS wall and then obtains the reinforcement load distribution for the limit state. The distributions are used to determine the required connection strength and to approximately assess the facing lateral deformation. For sufficient pullout resistance to be provided by each reinforcement, the maximum required tensile resistance is identical to the results based on the Mononobe–Okabe method. However, short reinforcement results in greater tensile resistances in the mid and lower layers as evinced by compound failure frequently occurring in GRS walls during an earthquake. Parametric studies involving backfill friction angle, reinforcement length, vertical seismic acceleration, and secondary reinforcement are conducted to investigate seismic impacts on the stability and lateral deformation of GRS walls.

关键词: geosynthetics     reinforced soil     retaining walls     seismic performance    

Modeling of shear walls using finite shear connector elements based on continuum plasticity

Ulf Arne GIRHAMMAR, Per Johan GUSTAFSSON, Bo KÄLLSNER

《结构与土木工程前沿(英文)》 2017年 第11卷 第2期   页码 143-157 doi: 10.1007/s11709-016-0377-3

摘要: Light-frame timber buildings are often stabilized against lateral loads by using diaphragm action of roofs, floors and walls. The mechanical behavior of the sheathing-to-framing joints has a significant impact on the structural performance of shear walls. Most sheathing-to-framing joints show nonlinear load-displacement characteristics with plastic behavior. This paper is focused on the finite element modeling of shear walls. The purpose is to present a new shear connector element based on the theory of continuum plasticity. The incremental load-displacement relationship is derived based on the elastic-plastic stiffness tensor including the elastic stiffness tensor, the plastic modulus, a function representing the yield criterion and a hardening rule, and function representing the plastic potential. The plastic properties are determined from experimental results obtained from testing actual connections. Load-displacement curves for shear walls are calculated using the shear connector model and they are compared with experimental and other computational results. Also, the ultimate horizontal load-carrying capacity is compared to results obtained by an analytical plastic design method. Good agreements are found.

关键词: shear walls     wall diaphragms     finite element modelling     plastic shear connector     analytical modelling     experimental comparison    

Effect of earth reinforcement, soil properties and wall properties on bridge MSE walls

《结构与土木工程前沿(英文)》 2021年 第15卷 第5期   页码 1209-1221 doi: 10.1007/s11709-021-0764-2

摘要: Mechanically stabilized earth (MSE) retaining walls are popular for highway bridge structures. They have precast concrete panels attached to earth reinforcement. The panels are designed to have some lateral movement. However, in some cases, excessive movement and even complete dislocation of the panels have been observed. In this study, 3-D numerical modeling involving an existing MSE wall was undertaken to investigate various wall parameters. The effects of pore pressure, soil cohesion, earth reinforcement type and length, breakage/slippage of reinforcement and concrete strength, were examined. Results showed that the wall movement is affected by soil pore pressure and reinforcement integrity and length, and unaffected by concrete strength. Soil cohesion has a minor effect, while the movement increased by 13–20 mm for flexible geogrid reinforced walls compared with the steel grid walls. The steel grid stresses were below yielding, while the geogrid experienced significant stresses without rupture. Geogrid reinforcement may be used taking account of slippage resistance and wall movement. If steel grid is used, non-cohesive soil is recommended to minimize corrosion. Proper soil drainage is important for control of pore pressure.

关键词: mechanically stabilized earth walls     precast concrete panels     backfill soil     finite element modeling     earth reinforcement    

标题 作者 时间 类型 操作

Lateral shear performance of sheathed post-and-beam wooden structures with small panels

期刊论文

Self-centring segmental retaining walls—A new construction system for retaining walls

期刊论文

Damage detection in beam-like structures using static shear energy redistribution

期刊论文

Parametric study of hexagonal castellated beams in post-tensioned self-centering steel connections

Hassan ABEDI SARVESTANI

期刊论文

Self-centering steel plate shear walls for improving seismic resilience

Patricia M. CLAYTON,Daniel M. DOWDEN,Chao-Hsien LI,Jeffrey W. BERMAN,Michel BRUNEAU,Laura N. LOWES,Keh-Chuan TSAI

期刊论文

Seismic progressive-failure analysis of tall steel structures under beam-removal scenarios

Behrouz BEHNAM, Fahimeh SHOJAEI, Hamid Reza RONAGH

期刊论文

Advances in polishing of internal structures on parts made by laser-based powder bed fusion

期刊论文

Damage assessment of laminated composite beam structures using damage locating vector (DLV) method

T. VO-DUY,N. NGUYEN-MINH,H. DANG-TRUNG,A. TRAN-VIET,T. NGUYEN-THOI

期刊论文

Slender reinforced concrete shear walls with high-strength concrete boundary elements

期刊论文

Behaviour of self-centring shear walls——A state of the art review

期刊论文

Experiment and calculation on seismic behavior of RC composite core walls with concealed steel truss

Wanlin CAO , Weihua CHANG , Changjun ZHAO , Jianwei ZHANG ,

期刊论文

我国木质林产品质量安全现状及管理对策

崔敏,段新芳,吕斌

期刊论文

Seismic effects on reinforcement load and lateral deformation of geosynthetic-reinforced soil walls

期刊论文

Modeling of shear walls using finite shear connector elements based on continuum plasticity

Ulf Arne GIRHAMMAR, Per Johan GUSTAFSSON, Bo KÄLLSNER

期刊论文

Effect of earth reinforcement, soil properties and wall properties on bridge MSE walls

期刊论文