Seismic performance evaluation of steel frame-steel plate shear walls system based on the capacity spectrum method

This paper presents some methods that the standard acceleration design response spectra derived from the present China code for seismic design of buildings are transformed into the seismic demand spectra, and that the base shear force-roof displacement curve of structure is converted to the capacity spectrum of an equivalent single-degree-of-freedom （SDOF） system. The capacity spectrum method （CSM） is programmed by means of MATLABT.0 computer language. A dual lateral force resisting system of 10-story steel frame-steel plate shear walls （SPSW） is designed according to the corresponding China design codes. The base shear force-roof displacement curve of structure subjected to the monotonic increasing lateral inverse triangular load is obtained by applying the equivalent strip model to stimulate SPSW and by using the finite element analysis software SAP2000 to make Pushover analysis. The seismic performance of this dual system subjected to three different conditions, i.e. the 8-intensity frequently occurred earthquake, fortification earthquake and seldom occurred earthquake, is evaluated by CSM program. The excessive safety of steel frame-SPSW system designed according to the present China design codes is pointed out and a new design method is suggested.     

Formwork lateral pressure of precast normal-concrete composite shear walls infilled with self-compacting concrete

Wall cracking and mold expanding due to concrete vibrations can be effectively solved through the application of precast normal-concrete composite shear walls infilled with self-compacting concrete (SCC). However, the high liquidity of SCC will induce a higher lateral pressure. Therefore, it is important to obtain a better understanding of the template lateral pressure. In this work, nine composite shear walls were experimentally investigated, focusing on the effects of two parameters, i.e., the casting rate and the section width of the formwork. The time-varying pressure was monitored during the SCC pouring. It is found that the increase of casting rate from 3.2 m/h to 10.3 m/h resulted in a higher maximum lateral pressure. The higher casting rate led to a longer time required for the lateral pressure to drop to a steady value. There was no correlation between the section width and the rate of decrease in the initial formwork pressure and stable value. Based on the test results, a formula considering the effect of casting speed for the calculation of SCC formwork pressure was established to fill the gap in the current standards and for engineering applications.     

剪力墙的布置高度对框架-剪力墙结构抗震性能的影响

为研究中断剪力墙设计的可行性及其对框架-剪力墙结构抗震性能的影响,对全高布置剪力墙、中断剪力墙布置结构的位移、层间刚度比、层间剪力进行分析。结果表明:1)中断剪力墙对X方向上结构的楼层水平位移影响较小,X方向在地震作用下产生较小的位移,有利于结构抗震,对Y方向的位移有一定影响,会产生一定的偏移;2)层间刚度比自下而上逐渐减小,建筑物不会因地震变化而出现大的刚度突变,可有效减小结构坍塌的概率;3)中断剪力墙对于Y方向的层间剪力影响更为明显,在进行地震作用分析时,含有应着重考虑Y方向的影响。中断剪力墙对框架-剪力墙结构的抗震性能影响不大。     

拟动力结构试验平台规划建设与教学改革

国内研究型大学、教学研究型大学和教学型大学的结构工程试验平台发展有其特点。多自由度拟动力试验平台规划建设包括结构力学基础教学试验加载系统,多自由度拟动力加载系统,试验平台的建筑、结构、设备设计指标等具体内容。试验平台规划建设教学改革建议包括:依托试验室的师资队伍建设,注重试验室特色发展,依托试验室的本科生教学科研等。     

T形钢管再生混凝土柱-钢梁框架节点抗震性能试验研究

为研究T形钢管再生混凝土柱-钢梁框架节点的抗震性能,取再生骨料取代率为100%,根据现行规范制作了3个节点试件模型并进行了拟静力试验。研究轴压比对节点抗震性能的影响,观察节点在加载全程中的破坏过程,分析滞回曲线、骨架曲线、延性、刚度退化、耗能能力及核心区剪切变形等抗震性能指标。结果表明:节点的破坏形态大体相似,表现为钢梁出现塑性铰的局部屈曲破坏,满足了强柱弱梁、强节点弱杆件的抗震设计要求;轴压比对节点的极限承载力和延性有一定影响,轴压比越大,节点的极限承载力越高,但延性和耗能能力会降低,且刚度退化越严重;节点的滞回曲线饱满、具有良好的抗震性能,可在抗震设防区及其他地区推广该类节点的使用。     

焊接钢架在桩基补桩中的应用

结合工程实践 ,分析有软弱下卧层的桩基不均匀沉降原因 ,论述焊接钢架在桩基补强中的应用及其优缺点     

黏弹性阻尼器在轻型门式钢架中的应用

以轻型门式钢架结构为研究对象,分析了黏弹性阻尼器的动力特性,建立了计算模型,采用目前通用的大型有限元分析软件ANSYS,建立了有吊车荷载作用的单层单跨门式钢架结构和消能减震结构两种不同的结构模型,并选取Elcentro地震波,在不同柱距下对两种结构模型进行了罕遇地震下的非线性时程分析,通过对计算结果的分析最终得出一些有益的结论。     

Ultimate strength of single shear bolted connections with cold-formed ferritic stainless steel

This paper is focused on the structural behavior of the single shear bolted connections with thin-walled ferritic stainless steel.The purpose of this study is to investigate the ultimate behaviors,such as ultimate strength and fracture mode of the single shear bolted connections of thin-walled ferritic stainless steel(low cost steel) rather than austenitic stainless steel(high cost steel).Bolt arrangement and end distance parallel to the direction of applied load are considered as main variables of the test specimens for bolted connections.Specimens have a constant dimension of edge distance perpendicular to the loading direction,bolt diameter,pitch,and gauge.A monotonic tensile test for specimens has been carried out and some bolted connections with long end distance showed curling(out of plane deformation) occurrence which led to strength reduction.The ultimate behaviors such as fracture mode,ultimate strength are compared with those predicted by current design codes.Further,conditions of curling occurrence and the strength reduction due to curling are investigated and modified strength equations are suggested considering the curling effect.     

双层钢板混凝土组合剪力墙的抗剪性能(英文)

为深入了解双层钢板混凝土组合剪力墙的抗剪性能,采用数值模拟的方法研究了钢板厚度、混凝土厚度、混凝土强度及组合剪力墙的跨高比等主要参数对该组合剪力墙抗剪性能的影响规律,并提出了该组合剪力墙弹性抗侧刚度及抗剪极限承载力的简化计算公式.研究表明:随着钢板厚度、混凝土厚度、混凝土强度等级的增加,组合剪力墙的抗剪性能均有较显著的提高;组合剪力墙跨高比的变化对其弹性抗侧刚度影响较大,而对其抗剪极限承载力的影响并不明显.通过将公式计算结果与有限元计算结果进行对比分析,发现提出的简化计算公式较合理,能较好地反映双层钢板混凝土组合剪力墙的实际受力状态.该结论可作为双层钢板混凝土组合剪力墙初步设计的参考建议.     

不同填充墙钢框架结构地震作用下的非线性分析

一钢框架结构分别以普通砌块和泡沫混凝土为填充墙材料,据此建立有限元模型来研究其对结构抗震性能的影响。根据数据分析,砌块填充墙和泡沫混凝土填充墙对结构的动力特性有不同程度的影响,结构的位移反应也有不同的表现。     

钢架柱底板厚度的设计方法

本文介绍了中、美、英国标准中钢架柱底板厚度设计方法和有限元法设计的方法的初步研究。     

可移动房屋钢框架结构试验研究

对风荷载作用下两层可移动房屋的静力进行试验研究,考察其结构的受力性能和变形机理.该结构由两个钢框架盒子单元组成,根据静力等效原则,采用在柱顶施加集中荷载来模拟水平风荷载,得到了框架结构的水平侧移和单元间的相对移动值.试验表明,盒子单元之间的相对移动将显著影响可移动房屋的水平侧移.     

冲击荷载作用下钢框架的动态响应分析

在冲击荷载作用下,钢框架结构的动态响应是一个复杂的非线性过程。运用ANSYS/LS-DYNA建立了钢框架的三维模型,对冲击荷载作用下钢框架的动态响应和破坏形态进行研究。采取多点积分算法,有效避免沙漏问题,保证计算结果精确。以冲击块与钢框架的碰撞冲击为例,研究了冲击速度、冲击块质量、冲击位置等参数对钢框架在横向冲击作用下动力响应的影响,并分析冲击荷载下钢框架的破坏形态。结果表明:冲击块的质量、速度、冲击位置的增加都会不同程度地加剧钢框架的动态响应;在冲击作用下,高应变主要出现在被冲击柱子的冲击区域、柱脚处和梁柱节点处;冲击荷载下钢框架的破坏形态为整个框架发生侧移,受冲击柱在冲击处翼缘出现局部屈曲,受冲击区域的截面发生弯扭,未受冲击柱出现倾斜。     

弯曲破坏模式配筋砌块砌体剪力墙刚度方程研究

利用18片弯曲破坏模式的足尺全灌芯配筋砌块砌体剪力墙的低周往复荷载试验,研究了在压弯剪复合受力状态下墙体的刚度衰减方程。墙体所用砌块的种类有190型、240型、290型3种,通过试验得到的滞回曲线,计算墙体的刚度,然后对刚度进行归一化,分别对初始刚度的归一化和峰值点刚度的归一化,得到刚度退化系数α_0=K_i/K_0和α_m=K_i/K_m。针对各次试验的刚度退化系数采用指数函数和多项式函数进行回归分析,得到了此种墙体的刚度衰减方程。研究结果表明:各次试验尽管参数不同,但得到的刚度拟合曲线比较接近,尤其是α_m曲线表现得更明显;无论是α_0还是α_m,采用多项式函数拟合的曲线与试验计算值更加接近;相比于指数函数,多项式函数的衰减更加缓慢,更能准确地反应此种墙体刚度的变化规律。     

Blast response of full-size concrete walls with chemically reactive enamel (CRE)-coated steel reinforcement

In this study, two full-size concrete walls were tested and analyzed to demonstrate the effectiveness of a chemically reactive enamel (CRE) coating in improving their mechanical behavior under blast loading: one with CRE-coated rebar and the other with uncoated rebar. Each wall was subjected in sequence to four explosive loads with equivalent 2, 4, 6-trinitrotoluene (TNT) charge weights of 1.82, 4.54, 13.6, and 20.4 kg. A finite element model of each wall under a close-in blast load was developed and validated with pressure and strain measurements, and used to predict rebar stresses and concrete surface strain distributions of the wall. The test results and visual inspections consistently indicated that, compared with the barrier wall with uncoated reinforcement, the wall with CRE-coated rebar has fewer concrete cracks on the front and back faces, more effective stress transfers from concrete to steel rebar, and stronger connections with its concrete base. The concrete surface strain distributions predicted by the model under various loading conditions are in good agreement with the crack patterns observed during the tests.     

Bilateral shear strength of rectangular frame column based on simplified space truss-arch model

To investigate the bilateral shear strength of rectangular frame column subjected to oblique horizontal load, we presented a simplified space truss-arch model developed from unilateral truss-arch model. Main parameters in the new model were the cross-sectional area, transverse reinforcement raito, axial load, and material strength of the column. The reduction coefficient of concrete sterength owing to the severe cracking of column was also introduced in the model. Finally, 14 specimens under oblique horizontal load were tested to verified the feasibility and applicability of the space truss-arch model.     

Probabilistic collapse analysis of steel frame structures exposed to fire scenarios

In this paper,we propose a probabilistic method for analysing the collapse time of steel frame structures in a fire.The method considers the uncertainty of influencing factors.Tornado diagrams are used for sensitivity analysis of random variables.Structural analysis samples are selected by Monte Carlo method,and the collapse times of different structural samples are calculated by fire time history analysis.A collapse time fragility curve is fitted according to the calculated collapse times of the samples.A reliability index of the collapse time is used as a quantitative standard to evaluate the collapse performance of a steel frame in a fire.Finally,this method is applied to analyse the collapse time fragility of an eight-storey 3 D steel frame structure under different compartment fire scenarios and fire protection levels.According to the collapse time fragility curve,the effects of the different fire scenarios and protection levels on the collapse resistance of the structure under fire are evaluated.     

轻钢结构临建房屋骨架结构有限元计算分析

以轻钢结构临建房屋骨架结构试验为基础,采用有限元分析软件Ansys提出轻钢结构临建房屋的有限元计算模型建立方法,并对轻钢结构临建房屋骨架结构的水平侧移进行计算和分析。计算结果表明,所采用的有限元计算模型建立方法正确合理,且轻钢结构临建房屋骨架结构在设计荷载作用下的水平侧移不能满足规范要求。     

Evaluation of in-plane shear test methods for composite material laminates

In-plane shear properties of composite material laminates are very important in structural design of composite material. Four commonly used in-plane shear test methods were introduced in this paper. In order to study the differences of various shear test methods, two ASTM standard in-plane shear test methods for composite material laminates were experimentally investigated. They are ±45° tensile shear test (ASTM D3518) and V-notched rail shear test (ASTM D7078). Five types of composite material laminates composed of E-glass fiber fabric and vinyl ester resin were utilized, whose stacking sequences are 03s, 0/903s, CSM/0/902s, ±453s and (0/90)2/(±45)2/(0/90)2s, respectively. The test results indicate that the ±45° tensile shear test can predict shear moduli of composite material laminates accurately. However, the predictions of shear strength using ±45° tensile shear test are significantly lower than those of V-notched rail shear test.