This paper investigates the axial compressive buckling behaviour of cold-formed thin-walled lipped square steel columns with lip openings, which can be employed in the elevator installation practice for existing residential buildings. Axial compression tests on five specimens were conducted, and a validated finite element (FE) model was established to perform 260 sets of parametric analyses, revealing the influence laws of key parameters, such as the member slenderness ratio, web width-to-thickness ratio, relative opening ratio, and number of stiffeners, on the load-carrying capacity of the members. The results show that the current Direct Strength Method (DSM) yielded non-conservative predictions for members governed by local and distortional buckling. Accordingly, the formulas for local-global interactive buckling and distortional buckling in the DSM were revised, and a strength amplification factor for stiffeners was introduced. The mean ratio of predicted values to experimental and FE results for the modified DSM is 0.994, with a coefficient of variation of 4.3%, providing a reliable basis for the engineering design of such members.

Owing to their irregular geometry, L-shaped steel-tube concrete column frame joints are prone to stress concentration at corners and welds, and the torsional performance of L-shaped columns is poor, which may lead to structural instability in torsion. Therefore, it is necessary to adopt a reinforcement method that enables easy fabrication and effective load transfer. In this paper, locally reinforced multichamber concrete-filled L-shaped steel columns and H-shaped beam (LRMCLSC-HB) joints are introduced. Three LRMCLSC-HB joints with different specifications in the beam-column joint area were subjected to quasistatic tests. Test findings reveal that the dominant failure mechanism was the formation of plastic hinges in the steel beam flanges. The hysteresis curves exhibit a full shape, demonstrating good seismic performance. A joint-reinforced column significantly enhances the specimen's mechanical performance indicators, including energy dissipation capacity, load-bearing capacity, and stiffness, by enhancing the wall thickness of the steel tube in the joint zone. Although extending the height of the stiffened column zone produces similar reinforcement effects, the degree of improvement remains relatively limited compared with that achieved through wall thickness augmentation. Additionally, the installation of a rectangular stiffener causes the plastic hinge to shift outwards. Finite element joint models were built in ABAQUS to corroborate the experimental findings. A subsequent parametric study evaluated the impact of different specifications of the joint-reinforced column and the thickness and arrangement of the vertical stiffener on the mechanical performance of the joints. The simulations show that increasing the thickness and height of the joint-reinforced column improves the seismic performance of the samples; however, the height increase has relatively limited effects. The arrangement of the vertical stiffener enhances both the shear strength and stiffness of the core zone. When the vertical stiffener is aligned with the long side rather than the short side of the rectangular chambers, the bearing capacity, initial stiffness, and energy dissipation capacity of the joint significantly improve. On the basis of the experimental and simulation analyses, a force transfer mechanism and a calculation formula for the ultimate flexural load capacity of this type of joint are proposed.

Autoclaved aerated concrete (AAC) is increasingly used in structural applications due to its low density, superior thermal and fire insulation, and ease of construction. Nevertheless, AAC is still employed predominantly as a building-envelope material in masonry systems, and its axial load-carrying behavior as a wall panel system-particularly the interaction with reinforcement and the influence of connection details-remains insufficiently understood. Therefore, this study addresses these gaps through axial compression tests on eight AAC wall panel specimens to evaluate the effects of panel layout, connection configuration, reinforcement detailing, and external steel restraint on mechanical performance. The results show that specimens with horizontal panel joints exhibited delayed joint cracking relative to those with vertical joints. Introducing reinforcement increased axial compressive capacity by 37.41%-42.53%. The difference in capacity between specimens reinforced with steel mesh cages and those with steel mesh sheets was only 3.73%, indicating comparable strengthening effects. However, mesh cages more effectively limited out-of-plane displacement. Applying fiberglass mesh at the joints curtailed crack initiation and propagation. External steel restraint further enhanced axial compressive capacity by 26.02%-49.11%. Finite element models were developed in Abaqus and calibrated against the test data to conduct a parametric study on the influences of panel thickness, reinforcement type, and bar diameter. Based on the experimental findings and parametric analyses, a modified design equation is proposed for predicting the axial load-carrying capacity of AAC wall panels.

To overcome the shortcomings of traditional shear walls, a new type of M-section lightweight steel-reinforced concrete (MLSRC) shear wall is proposed. One cast-in-place shear wall and three MLSRC shear walls were designed. Through quasistatic tests, the seismic performance was investigated, with the research parameters being the dowel arrangements and the connection methods between the upper and lower layers of the shear wall. The results revealed that the plastic region of the wall concentrated mainly near the horizontal joint section. From the top of the lap rebar to the top surface of the foundation, the strain in the lap rebar gradually increased, whereas the strain in the M-section lightweight steel gradually decreased. The stiffness, ductility, and load-bearing capacity values for the three types of MLSRC shear walls are essentially consistent. The failure modes are similar to that of the cast-in-place concrete shear wall. Noncontact lap splicing of the upper and lower layers of rebar can effectively transfer stress. The three rebar arrangements have similar impacts on the seismic performance of MLSRC shear walls, and the shear walls exhibit comparable seismic performance to that of cast-in-place concrete shear walls. Finally, finite element models of the specimens were established via finite element software, with the concrete damage, rebar stress distribution, and hysteresis curves closely matching the experimental results.

To investigate the mechanical performance of multicell T-shaped concrete-filled steel tubular (MCT-CFST) columns, five short columns composed of a rectangular cell and two U-shaped cells were tested under axial and eccentric compression loads. For the axial compression samples, the steel tube surface underwent wave buckling, and local buckling failure occurred along the X-axis direction of the section. For the eccentric compression samples, overall bending occurred first; then, local buckling deformation occurred on the surface of the steel tube. Furthermore, a finite element model (FEM) of MCT-CFST short columns was established in ABAQUS software. The FEMs were validated by the test results to further investigate the influence of the construction parameters on the axial and eccentric compression performance of the MCT-CFST short columns. Finally, the EC4, GB 50936 and JGJ 138 specifications were selected to predict the load-carrying capacity of the MCT-CFST short columns under eccentric loading. Compared with GB 50936, JGJ138 and EC4 yield good predictions according to the test and simulation results.

To enhance the integrity of the prefabricated steel cage and facilitate transportation, lifting, and on-site positioning, M-section lightweight steel (MLS) can replace part of the longitudinal reinforcement of the reinforcement cage, forming an M-section lightweight steel reinforced shear wall (MLSRSW). Four full-scale specimens were designed for quasi-static tests, including three MLSRSWs with the same geometric dimensions and reinforcements but varying axial load ratios (ALRs), along with one reinforced concrete shear wall (RCSW) serving as the control specimen. All specimens exhibited bending-shear failure. The peak load-carrying capacities of SW2, SW3, and SW4 (with ALRs of 0.1, 0.2, and 0.3, respectively) are 389.17, 404.54, and 439.12 kN, respectively, whereas the corresponding values of mu for these specimens are 2.77, 2.64, and 2.36, respectively. This finding indicates that the lateral load-carrying capacity of the MLSRSWs is positively correlated with ALR, whereas ductility is negatively correlated with ALR. The lap splices between the MLSs and the protruding reinforcements can effectively transfer stress, but the deformation in this area is minimal, resulting in the deformation capacity of the MLSRSW being weaker than that of the RCSW. Finite element (FE) models were developed to simulate the specimens numerically and verify the experimental results. Based on these models, the effects of the ALR and overstrength ratio gamma 0 on the seismic performance of MLSRSWs were investigated.

In this paper, a strengthened T-shaped concrete-filled steel tubular (CFST) column-steel beam joint is proposed. The joint is strengthened in the core region of the column wall as well as the beam, to avoid buckling of the column wall and outward displacement of the plastic hinge at the beam end. To study the damage modes and seismic performance of the joint, low-cycle loading experiments on two full-scale specimens of the joint were carried out. The results show that each specimen was damaged by plastic hinging of the steel beam flanges, the column walls did not buckle, and all had a good seismic performance. In addition, Abaqus finite element software was utilized to optimize the joints by analyzing the effects of changing the dimensions of the strengthened column and modifying the structure of the beam-column connection. Simulation results show that increasing the thickness and height of the strengthened column wall enhances the joint's load capacity, stiffness, and energy dissipation. it is recommended that the width-to-thickness ratio of the strengthened columns should be at most 0.08 and the beam-to-column height ratio should be kept at least 1.3. Additionally, two optimization methods, reducing the wall thickness of the steel corbel and weakening the steel beam flange, can effectively reduce weld tearing at the beam-to-column connections, while guaranteeing a good seismic performance. It is suggested that the slope of the steel corbel is not less than 1:6.25, and the weakening ratio of the steel beam flange is not greater than 0.267.

In order to study the compression-bending behavior of rectangular concrete-filled steel tubular(CFST)columns with large aspect ratio,eccentric compression tests were carried out,and four groups of specimens were compared with follow-up finite element simulation,including the comparative analysis of column performance under different eccentricity,aspect ratio,steel tube wall thickness and section dimensions.Finally,the eccentric compression bearing capacity of columns is calculated according to four commonly used domestic and foreign codes,and the applicability of the existing codes is verified by comparison.The results show that the failure modes of the specimens are the long side bulging.When the load is less than 80％of the ultimate bearing capacity,the strain distribution at the height of the cross section obeys the plane section assumption.As the eccentricity increases,the ductility of the column increases firstly,after the eccentricity exceeds 0.205,the ductility of the column begins to decrease.As the wall thickness increases,the ductility of the column increases firstly,after the wall thickness reaches 8 mm,the ductility of the column begins to decrease.With the increase of aspect ratio,the ductility of column decreases.As the section dimension increases,the ductility of the column decreases when the wall thickness is constant.When the wall thickness increases in equal proportion,the ductility of the column does not change much.With the increase of aspect ratio,section dimension or steel tube wall thickness,the bearing capacity of column increases.With the increase of eccentricity,the bearing capacity of column decreases.It is more accurate to calculate the eccentric compression bearing capacity of CFST columns with large aspect ratio by referring to the JGJ 138-2016 specification.

To study the seismic performance of a steel frame with grooved fully bolted semirigid connections, a single-story single-span steel frame was tested under pseudostatic cyclic loading. The failure modes, ductility, and bearing capacity of the specimens were analyzed. The results showed that the gusset plate at the beam end yielded first. The plate opened when it was under tension, and the slotted bolt hole slipped. The weld tore at the connection between the steel beam flange and the plate, but there was no obvious deformation of the column wall. The hysteretic curve exhibited a plump shuttle shape in the later stage of loading, which indicated that the frame had good ductility and a desirable capacity to dissipate energy. However, pinching behavior occurred because the gusset plate formed gaps, and the bolt slipped. The yield displacement in the test was 56.3 mm, the maximum loading displacement was 128 mm, and the displacement ductility was 2.27. Finally, a finite element model was established using ABAQUS, and the results showed that the model could provide reasonably accurate predictions of the experimental results. The ductility of the structure could be improved both by increasing the bolt diameter at the node plates and by increasing the thickness of the beam end node plate. This study provides an important reference for the development of semirigid beam-to-column joints in steel frames.

Concrete sandwich walls are commonly used as the exterior wall panels of a structure, in which the wall suffers out-of-plane bending under strong wind conditions. This paper aims to investigate the bending performance of concrete sandwich walls under actual boundary conditions through experimental and analytical methods. In total, four concrete sandwich walls were tested to detect the influence of openings and loading direction. Typical failure patterns were characterized and discussed. The load-displacement curves of four test specimens were analyzed. It was indicated that the bearing capacity of the walls under negative bending conditions was higher than that under positive bending conditions, owing to the additional constraints provided by the steel beams. Strain distributions of wall specimens were also discussed in order to obtain the composite action of the sandwich walls between the upper and lower layers of concrete. In addition, the finite element model (FEM) was developed by ABAQUS to provide insights into the bending performance of the sandwich walls. Through comparison with the test results, the FEM was verified with a good level of accuracy. Subsequently, the degree of composite action of the sandwich walls was assessed in terms of both the moment of inertia and bearing capacity. From the experimental and numerical results, it demonstrated that the bearing capacity of concrete sandwiched wall under negative direction was higher than that under positive direction owing to the constraints of steel beam. The derived composite action degree could be employed to evaluate the out-plane bending stiffness and strength of sandwiched concrete wall. Both the experimental and analytical results in this paper are beneficial for the design of sandwich walls under bending conditions.

文章基于滑移耗能思想,提出一种可以控制损伤并实现震后修复的多腔钢管混凝土T形柱 H 型钢梁装配节点;通过改变上下连接板件的厚度与腹板连接方式改变连接处刚度,对 6 个试件进行模拟分析,得到相应的滞回曲线、骨架曲线、力学性能指标及转动能力.研究结果表明:合理控制翼缘连接盖板厚度可以转移塑性铰、保护节点核心区,使节点具有及时修复的功能;腹板连接件可以提高节点的刚度、承载力及延性;腹板连接件不宜过大,应该与翼缘保持一定的缓冲距离.

为提高采用梁柱栓焊连接节点的变电站的安装施工效率,考虑变电站钢结构受力性能特点,提出在方钢管柱4个角部的45°方向焊接柱端钢板,钢梁端部焊接梁端钢板,然后通过高强螺栓连接梁端钢板和柱端钢板形成一种新型X形插板连接型钢结构梁柱装配式节点.设计了4个具有不同梁端钢板厚度和螺栓直径的节点模型并进行了受力性能试验.采用ABAQUS软件建立了节点模型并验证了模型的准确性,基于校核后的节点有限元模型分析了柱端钢板厚度和螺栓数量对节点受力性能的影响.结果表明:节点破坏主要发生在钢梁与梁端钢板焊缝连接处;增加梁端钢板厚度和螺栓直径能显著提高节点的转动刚度和承载力,但仍为半刚性连接节点;增加柱端钢板厚度和增加螺栓数量可以减小柱端钢板的损伤,但对梁端钢板损伤几乎不产生影响,同时增加螺栓数量的设计方式还可以提高节点的承载力.

文章以钢框架厂房产生楼板温度裂缝为案例,采用ANSYS有限元分析软件对楼板各组合工况进行建模计算,将建模计算结果与温度裂缝实际分布特征进行对比,分析理论计算结果与实际情况两者之间的符合程度.

为探究不同构造措施对CFRP加固方钢管柱稳定性的影响,设计制作了 14根粘贴纵向和环向CFRP的方钢管柱试件,通过静力加载的方式研究了 CFRP的层数、方向和位置对加固方钢管柱稳定性的影响.试验结果表明:在方钢管柱端部和中部粘贴环向CFRP对纵向CFRP起到了环箍作用,柱中粘贴环向CFRP比仅在柱端粘贴环向CFRP提高了约34％的柱中侧移变形值;当偏心距分别为0 mm、10 mm、20 mm时,相比于未加固试件,包裹1～3层纵向CFRP加固试件的极限承载力提高了 9％～19％;在方钢管柱纵向CFRP的外侧粘贴环向CFRP能够限制内层纵向CFRP的提早剥离,可有效提高构件的延性;在实际工程应用中,建议满布粘贴3层纵向CFRP和沿柱高1/4～3/4区域粘贴环向CFRP作为加固受压方钢管柱的构造措施.

设计试验分别探究了环向粘贴CFRP和纵向间隔粘贴CFRP作为构造措施对圆钢管柱受压性能的影响.设计了 3根在端部和柱中粘贴环向CFRP的圆钢管,以探究环向CFRP对圆钢管偏心受压性能的影响,圆钢管整体破坏模式皆为失稳破坏,但CFRP的破坏方式有差异.试验现象和数据分析表明,环向CFRP对纵向CFRP起到了环箍作用,提高了试件的刚度和峰值后延性,沿柱高1/4～3/4区域环向粘贴CFRP可作为加固受压圆钢管柱的构造措施.设计了 5根圆钢管柱,在柱中纵向间隔粘贴CFRP,探究CFRP纵向粘贴间距对柱轴压性能的影响,试验破坏现象皆为整体失稳破坏,根据已有试验参数,进一步设计了 2根圆钢管柱进行有限元分析.试验现象、数据及有限元分析表明,在间隔粘贴CFRP加固圆钢管柱的构造方法中,粘贴间距宜取30～40 mm.

为探究CFRP加固轴压方钢管短柱局部稳定承载力,设计制作了24个不同宽厚比试件,分为A、B两组,试验通过静力加载分别研究了试件长细比、CFRP加固方向及其粘贴层数对CFRP加固方钢管短柱局部稳定承载力以及破坏模式的影响.研究结果表明:24个试件均是由于局部失稳而破坏;方钢管短柱宽厚比与长细比对其初始刚度影响较小,但随着方钢管短柱宽厚比的增加其延性有一定程度降低.当方钢管短柱长细比在7～28范围内时,随着长细比的增加,环贴加固的效果慢慢减弱,纵贴加固的效果慢慢增强;当长细比在23～25时,环贴加固与纵贴加固的试件极限承载力相同;当长细比大于25时,采用纵贴CFRP加固方式较好;当长细比小于23时,采用环贴CFRP加固方式较好.

装配式高层钢结构住宅产品生产全过程涉及多专业、多阶段的信息协同,为高效、高质量地完成住宅产品建造,有必要对其产业链信息化构架进行研究.文章分析了全产业链信息协同的底层逻辑,建立基于BIM-EMS深度融合技术的信息化构架系统,提出了实际应用中的关键技术路径,开发了可用于实际工程项目的一体化平台,最后通过工程示范验证了其科学合理性.

开展与主体结构点式连接、同时配制GFRP连接件及钢筋桁架连接件预制混凝土夹心保温外挂墙板静力压弯试验,并利用ABQUS有限元软件建立外挂墙板抗弯计算模型,将其与试验结果进行对比.在验证了有限元分析模型准确性的基础上,对连接件的种类,连接件的布置方式、间距等影响墙板抗弯性能的主要因素进行参数化分析.分析结果表明GFRP连接件、钢筋桁架连接件的布置间距和钢筋桁架连接件的直径对墙板抗弯性能影响较大,钢筋桁架连接件的强度等级影响相对较小.

斜交网格钢框架-混凝土核心筒结构施工过程中由于钢、混凝土两种材料随时间变化的材料特性不同,外钢框架柱与内混凝土核心筒会存在竖向变形差异,过大变形差异会影响工程施工质量和结构安全.考虑结构施工过程的时变效应,采用变刚度分阶段分析方法建立有限元分析模型,对其进行施工全过程数值模拟分析.结果表明:随着施工过程的进行,斜交网格,框架与混凝土核心筒的竖向变形值与竖向变形差都呈现递增的状态,其变形增长速率都呈现出先慢、后快、再慢的规律;确定斜交网格变形协调规律后,根据整体模型数值模拟结果和斜交网格框架斜构件变形简图,计算分析得到构件加工控制补偿量;提出采用分段累加找平的方法得到混凝土核心筒施工找平量.