黏弹性减震楼盖与传统楼盖钢框架抗震性能对比研究

为量化研究黏弹性减震楼盖(压型钢板组合楼板与H型钢梁间设置夹层黏弹性减隔震支座)钢框架的抗震性能,给出了减震楼盖钢框架梁与传统楼盖钢-混凝土组合梁的抗弯刚度对比关系,考虑减震楼盖组合梁效应缺失对框架整体抗侧刚度进行修正,建立了减震楼盖钢框架动力分析模型。采用所建立的模型,计算设置黏弹性减震楼盖的多层钢框架结构地震响应,并与传统楼盖钢框架地震响应进行对比,量化了黏弹性减震楼盖钢框架相对于传统钢框架的抗震性能提升。研究结果表明:由于减震楼盖的黏弹性支座引入可观的附加阻尼,框架整体地震响应可得到有效控制;对于各层均设置黏弹性减震楼盖的钢框架结构,在常规设计范围内,其楼面加速度、层间侧移可比传统楼盖钢框架降低30%~40%;对于多层减震楼盖钢框架,其上部楼层的减震楼盖支座耗能贡献明显大于底部楼层的黏弹性支座耗能贡献;仅在结构上部楼层设置减震楼盖时,其对地震响应的减控效率可与全楼层设置减震楼盖接近。

基于快速群搜索算法的钢框架结构多目标抗震优化

本文以三跨六层平面钢框架的结构总质量和总动应变能最小作为优化目标,结合Pareto最优解理论与拥挤距离机制提出了一种新的适用于钢结构抗震优化设计的多目标算法:多目标快速群搜索算法MQGSO(Multi-objective Quick Group Search Optimization)。通过振型分解反应谱法进行结构分析,优化的计算结果表明:该算法在处理带约束的平面钢框架的不同抗震性能多目标优化时,具有良好的收敛效果和较快的收敛速度,且Pareto前沿分布均匀宽泛,可为钢框架结构抗震优化设计提供可行的设计方案。

基于遗传算法的抗震钢框架多目标优化设计

考虑抗震钢框架优化问题具有多目标的特点,在遗传算法的基础上对抗震钢框架多目标优化设计进行了探讨．在无约束Pareto排序遗传算法的基础上,提出了一个简单、实用而又可以避免采用罚函数的全新排序方法,在此基础上形成了一种求解有约束多目标优化问题的Pareto遗传算法(CMOPGA),并给出了具体的算法流程图．以钢框架重量最轻和结构总动应变能最小为目标,基于相关的设计规范,给出了抗震钢框架多目标优化问题的一种合理提法．采用CMOPGA对一个两跨六层抗震钢框架实例进行了多目标优化设计,并提出了一个在Pareto最优解集的基础上选取妥协解的相对最小距离妥协原则．算例结果表明,采用CMOPGA求解抗震钢框架多目标优化问题是可行和有效的．

国家体育馆型钢混凝土框架-钢支撑抗震体系设计与研究

对大跨度超大空间体育场馆抗震体系设计提出新的布局和思路,成功地将型钢混凝土框架-钢支撑体系运用到国家体育馆的抗震设计中,对这种新型结构布局产生的问题和特点进行分析。由于钢支撑的斜向交接,更增加了型钢梁柱节点的复杂性,对新型平面三向交叉变截面节点建立力学模型并对其力学特征予以探讨。对复杂型钢节点及截面的开孔影响进行比较和分析,解决型钢与钢筋的结合问题。

对抗震钢框架板件宽厚比限值与相应的地震作用设计取值的细化和完善

在文献[1]的基本思路和初步结果的基础上,对钢结构中按弹性准则设计的截面,根据腹板屈曲与否对其进行分级;改进、完善和细化了框架截面等级与地震作用取值的对应关系,使之更趋合理;给出了各等级截面的框架以众值烈度地震作用效应表达的地震组合设计式,使实际应用更为方便。

基于Pushover分析的钢框架地震响应概率统计特性

以钢框架为例,考虑地震作用、结构构件面积、材料弹性模量、屈服强度、恒荷载和活荷载的随机性,在不同水平加载模式下对结构进行Pushover分析,采用K-S检验法,对最大层间变形和项层位移的概率统计特性进行了分析.结果表明,在给定地震烈度下基于Pushover分析的钢框架最大层间变形和顶层位移均服从极值Ⅱ型分布,且不同水平加载模式对统计参数有一定影响.

考虑折叠效应的一种钢结构新型梁-柱节点的低周反复试验研究

提出了一种新型钢框架梁-柱削弱节点形式——波纹腹板削弱型节点.这种新型梁-柱节点是将靠近柱翼缘的工字梁腹板局部改成具有折叠效应的波纹腹板来削弱工字梁的抗弯能力,将失效部位从梁-柱节点的焊接部位转移到工字梁波纹腹板所在截面处,达到塑性铰外移的目的.而且波纹腹板还可以阻止受压翼缘在屈服之后发生局部失稳.本文通过低周反复试验考察了波纹腹板削弱型梁-柱节点的抗震性能.试验表明,波纹腹板削弱型梁柱节点的强度破坏出现在波纹腹板处的截面,梁柱连接处的焊缝没有破坏,实现了塑性铰外移的目的;而且由于波纹腹板的支撑作用,翼缘在屈服后没有严重局部失稳.另外,通过和传统梁柱节点对比发现,波纹腹板新型梁柱节点在出现塑性铰后没有出现明显的强度退化现象,波纹腹板削弱型梁柱节点的滞回曲线稳定饱满,具有更好的耗能性能.综上所述,该波纹腹板削弱型梁柱节点起到将塑性铰从梁柱根部外移、护梁柱焊缝的作用,具有良好的延性和滞回耗能性能,可以替代传统梁柱用于钢框架结构.

Numerical and experimental study on seismic behavior of concrete-filled T-section steel tubular columns and steel beam planar frames

The seismic behavior of planar frames with concrete-filled T-section columns to steel beam was experimentally and numerically studied. A finite element analysis （FEA） model was developed to investigate the engineering properties of the planar frames. Two 1：2.5 reduced-scale specimens of T-section concrete-filled steel tubular column and steel beam of single-story and single-bay plane frames were designed and fabricated based on the design principles of strong-column, weak-beam and stronger-joint. One three-dimensional entity model of the investigated frame structure was built using a large-scale nonlinear finite-element analysis software ABAQUS. Experimental results show that the axial compression ratio has no effect on the failure mode of the structure, while with the increase of axial compression ratio and the dissipated energy ability increasing, the structural ductility decreased. The results from both experiments and simulations agree with each other, which verifies the validity and accuracy of the developed finite element model. Furthermore, the developed finite element model helps to reflect the detailed stress status of the investigated frame at different time and different positions.

Research on the direct damage-based seismic design method of RC frame structures

Based on the existing research, this paper presents an innovative methodology to realize direct damage-based seismic design for RC frame structures by mobilizing ESDOF theory and the damage-based strength reduction factor（RD factor）. A design example is then followed to verify this method.

Research on Seismic Reliability and Damage of Reinforced Concrete Frame

This paper first introduces the basic principle of seismic risk analysis, and then put forward the basic concept of structures global seismic fragility, aiming at the existing problems of traditional analysis method, combined the method of analytical approximation degree of structure reliability with Performance-Based Seismic Design （PBSD）, put forward the analysis method of structural reliability and the performance of the global seismic fragility, are calculated by using the finite element reliability method of structures global seismic fragility. Taking the maximum interlamination relative deformation as indicators of overall performance, we analyze seismic fragility of five storey RC frame structure, rendering the seismic fragility curves corresponding to different performance requirements and different earthquake action.

Seismic failure mode improvement of RC frame structure based on multiple lateral load patterns of pushover analyses

The structural failure under severe ground motions is primarily caused by their unreasonable seismic failure mode (SFM). This paper provides a methodology aiming at the SFM improvement of reinforced concrete frame structure. An RC frame is modeled and three types of failure criterion are defined as the premise of SFM. Static pushover analysis is adopted to identify the SFM. The dominant failure modes and failure paths of the structure are obtained in three lateral load patterns (inverted trian- gular distribution, uniform distribution and adaptive distribution). Based on the pushover analysis, the sequential failure of components and the probability of the occurrence of plastic hinges are determined. By this, weak components of the structure are detected and herein are strengthened. The project cost of the proposed strengthening strategy increases by 2.4%. Capacity spectrum method is used to study the performance of the strengthening structure. Pushover analysis is conducted again to present the improvement of strength and ductility. Lateral drift and local response through IDA are also studied to indicate that the strengthening of some columns and beams can improve the SFM to enhance the seismic capacity of structure.