Research and development of seismic base isolation technique for civil engineering structures

Base isolation is one of the most promising alternatives among the structure control methods. In recent decades, base isolation has been seriously considered for civil structures, such as buildings and bridges, subjected to ground motion. The research achievements and development of seismic base isolation technique for civil structures in Huazhong University of Science and Technology (HUST) are introduced. The achievements include project applications, experimental research results and theoretical innovation.     

Seismic performance evaluation for super-long span cable-stayed bridges

Based on the capacity/demand analysis of bridge components, and life cycle and performance based seismic design principles, a practical procedure is developed for the seismic performance evaluation of super-long span cable-stayed bridges. According to the procedure, the seismic performance evaluation of the Su-Tong Bridge,which is a cable-stayed bridge with a main span of 1088m, is completed, and the practicality of the procedure is validated. The earthquake resistance level for super-long span cable-stayed bridges is discussed, including the earthquake level, its corresponding structural performance and check indices. And a set of formula for capacity/demand ratio calculation of bridge components is proposed.     

基于推覆分析混凝土框架摇摆墙结构抗震性能研究

RC frame rocking wall structure is a new structure system, which combines RC frame with rocking wall. A 6-story RC frame following current design practice is taken as an example to study the seismic behavior of the new system. Elastic-plastic model is established, and pushover analysis is conducted by using a finite element program called Abaqus and a user subroutine library called PQFiber. The analysis results suggest that: (1) the rocking wall can significantly improve the strength and ductility of the entire structure. (2) Thanks to the rocking wall, the inter-story drift becomes more uniformly distributed and the story failure mechanism is prevented, although the rocking wall does not contribute much to avoid the ‘Strong beam weak column’ yielding mechanism. (3) The inner force distribution of the rocking wall is similar to a veridical placed simple supported beam.     

Study on the shock absorbing technique of high speed railway bridges

Based on the idea of “bearing function separation ”, a structural member called shock absorber that makes use of its plastic deformation, is presented for reducing the seismic response of the bridge. The design criterion, for matching material stress, strain and earthquake fortification aim, is also given. The analysis results show that the high speed railway box girder with the absorber in this paper has great reduction of seismic response of the bridge piers.     

国内节能型剪力墙技术研究和应用现状分析

节能型剪力墙体系主要由承重-保温型结构材料构成,轻骨料混凝土是应用较多的承重-保温型结构材料。本文介绍了常用的一些轻骨料混凝土的材料性能和力学性能,如抗压强度、导热系数及应力-应变本构关系等。通过对相关文献结果的比较分析得出,轻骨料混凝土剪力墙在自身热工性能上有明显改善。力学性能方面,在承载力满足设计要求的前提下,延性性能优于普通混凝土剪力墙,拥有较高的抗震安全储备。同时介绍了免拆模复合剪力墙体系和新型夹心剪力墙体系,论述了它们的热工性能和构造组成。通过对比分析,得出轻骨料混凝土是节能型剪力墙体系中具有广阔应用前景的承重-保温型材料。     

有限宽度和椭圆孔形状对缺口层合板强度预测的影响

本文采用有限元方法对正交各向异性材料含有不同椭圆孔形状的有限宽度板作了分析,给出了有限宽度和椭圆孔形状对应力集中因子K₁和孔边应力分布σ_y(x,0)的影响公式。数值结果表明:正交各向异性板的有限宽度和椭圆孔形状对K_r和σ_y(x,0)的影响均与各向同性材料不同,所以有限宽度和椭圆孔形状将对缺口层合板强度的预测产生影响。      

复合材料加筋板的动力分析

本文构造了九自由度三角形拟协调罚函数复合材料板单元与六自由度复合材料梁单元,考虑了剪切变形与转动惯量的影响。用这两种单元对复合材料加筋板的自由振动、阻尼特性和瞬态响应问题进行了研究,给出一些有益结果。      

第二代基于性能地震工程中的地震易损性模型及正逆概率风险分析

第二代基于性能地震工程理论中的地震易损性主要是指结构构件以及非结构构件的抗震能力,与传统地震风险理论中的地震易损性定义和内涵并不相同。为了澄清二者的不一致性,首先介绍传统地震风险理论中地震易损性的定义和概率模型,然后指出第二代基于性能地震工程理论存在五个层次的地震易损性模型:地震需求易损性模型、抗震能力易损性模型、地震损伤易损性模型、地震损失易损性模型和抗震决策易损性模型,指出了这五种模型的区别及其相互关系,推导得到了地震需求易损性模型和地震损伤易损性模型分布参数的解析表达式。在此基础上,根据不同的不确定性传递路径,提出了正向PBEE和逆向PBEE的概念,以通过不同方式求解第二代基于性能地震工程理论的风险积分公式。基于地震危险性函数的近似表达式以及地震易损性模型及其分布参数的解析表达式,通过正向PBEE和逆向PBEE方法,分别得到了具有相同表达形式的工程需求参数EDP、地震损伤DM和决策变量DV三个层次的概率地震风险表达式。通过该文的研究,将传统地震风险分析理论与第二代基于性能地震工程理论统一在一致的理论框架之中。     

输电塔－大垂度电缆体系的地震反应上限

本文将输电塔－大垂度电缆体系的计算简图近似为折线形杆链体系，在刚度特性不确知的情况下，可利用“最不利可能变形状态”替代振型，并做极限计算，从而确定出地震反应的上限。     

输电塔－大垂度电缆体系的地震反应上限

本文将输电塔－大垂度电缆体系的计算简图近似为折线形杆链体系，在刚度特性不确知的情况下，可利用“最不利可能变形状态”替代振型，并做极限计算，从而确定出地震反应的上限。     

铰支桁架-框架结构抗震设计与性能研究

合理设计的框架会因为地震力分布不均匀致使框架的部分楼层梁率先屈服,导致结构层间位移角不均匀系数（DCF）增加,很难出现所有楼层梁端和柱底出铰的完全梁铰机制。为改善普通钢框架层间集中损伤和侧向刚度偏小问题,提出在框架中设置拉链柱和斜撑,形成铰支桁架-框架,控制框架侧向位移大小和分布。推导了框架弹性DCF值,并以此作为铰支桁架-框架的DCF目标值,进而提出了铰支桁架与框架的合理刚度比;给出了基于DCF抗震设计流程,设计算例达到了预期的位移和DCF性能目标。对比了框架、摇摆墙框架和铰支桁架-框架的抗震性能,结果表明:铰支桁架可以提高框架的抗侧刚度,使框架的塑性铰分布模式由不完全梁铰机制转变为完全梁铰机制,使框架层间位移角及剪力分布均匀;相比于摇摆墙框架,铰支桁架-框架具有较大的侧向刚度和相近的侧向变形模式。     

双重抗震结构及其设计参数的分析研究

本文根据多道抗震设防概念,对双重抗震结构的设防目标进行了探讨,明确了主、 次结构的功能．文中利用单自由度双重结构分析模型,对主、次结构的合理参数关系进行了 计算分析,提出了有关抗震设计建议。有关结果同样也适用于滞迟型减震控制结构。     

磁流变阻尼器优化设计及结构地震损伤控制

该文通过LS-DYNA 程序二次开发了磁流变(MR)阻尼器的Bouc-Wen动力滞回模型、半主动控制律和钢材的弹塑性损伤本构模型,进而实现应用通用有限元程序精细化模拟受控结构损伤发展过程的目的.基于损伤本构模型,提出结构构件和结构层的抗震性能指标,并应用该指标对结构各层阻尼器的最大出力进行优化设计.对一9 层Benchmark 钢框架结构进行损伤控制研究,采用IDA 方法对控制前后结构的抗震性能进行分析,结果表明:MR 阻尼器优化设计后受控结构的损伤累积效应较无控结构明显减小,损伤分布范围更广,塑性耗能能力和抗震能力都得到显著提高.     

地震工程:从抗震、减隔震到可恢复性

近年我国地震工程研究的发展呈现从抗震、减隔震走向可恢复功能的趋势。地震可恢复功能可定义为:受到地震动输入扰动后,结构、系统、城市具有可恢复功能的能力。对于工程结构而言,地震可恢复功能结构不仅要求结构在地震作用下保护生命,而且要求结构在震后快速恢复,减少对正常使用的影响。该文首先介绍了地震可恢复功能的基本概念,围绕地震可恢复功能结构,从设防目标、规范标准、结构体系、设计方法、性能指标以及工程应用等方面阐述了可恢复功能结构的特点及其与传统抗震结构的区别,最后对可恢复功能结构的未来进行了展望。     

日本东北大地震之隔减震建筑考察与思考

作者于2011年6月14日-18日参加了中日建筑结构技术交流会组织的中日专家联合考察团,实地考察了仙台地区在3月11日日本东北地区太平洋近海地震中的地震灾害情况,重点对隔、减震建筑在此次里氏8.8级大地震中的表现进行了调研。该文概述了隔、减震技术及其在日本应用的基本情况,重点介绍了隔减震结构在此次地震中的表现,并给出了隔减震结构应用的若干结论和体会。     

INFLUENCE OF DAMPING MODELS ON DYNAMIC ANALYSES OF A BASE-ISOLATED COMPOSITE STRUCTURE UNDER EARTHQUAKES AND ENVIRONMENTAL VIBRATIONS

Structural design simultaneously governed by earthquakes and environmental vibrations has received a lot of attention in recent years.Base-isolated composite structures are typically used in the above-mentioned structural design.The corresponding analysis involves validating structural safety under earthquakes and human comfort under environmental vibrations through a time-history analysis.Thus,a reasonable damping model is essential.In this work,the representatives of viscous damping model and rate-independent damping model,namely the Rayleigh damping model and uniform damping model,were adopted to investigate the influence of damping models on the time-history analysis of such structural designs.The energy dissipation characteristics of the above-mentioned damping models were illustrated via a dynamic test of recycled aggregate concrete specimens.A case study was performed on a base-isolated steelconcrete composite structure.The dynamic responses under the excitation of earthquakes and environmental vibrations were compared using different damping models.The uniform damping model was found to be more flexible than the Rayleigh damping model in dealing with excitations with different frequency components.The uniform damping model is both theoretically advantageous and easy to use,demonstrating its potential in dynamic analysis of structures designed simultaneously governed by earthquakes and environmental vibrations.     

带暗支撑短肢剪力墙及核心筒抗震研究与应用

提出了钢筋混凝土带暗支撑异形截面短肢剪力墙,提出了带暗支撑核心筒。对不同设计参数、不同受力特点的钢筋混凝土带暗支撑异形截面(一字形、T形、L形、Z形)短肢剪力墙及带暗支撑核心筒模型进行了低周反复荷载下的抗震性能试验研究,较系统地分析了其承载力、刚度、延性、滞回特性及耗能能力。在试验研究的基础上,建立了带暗支撑异形截面短肢剪力墙及核心筒的力学模型,提供了抗震设计方法,在实际工程应用中取得了良好的效果。