地震作用下岩溶加固地基抗震构造评估模型分析

针对当前在地震作用下岩溶加固地基抗震构造的评估模型评估范围不全面,导致评估结果准确性低下的问题,提出地震作用下岩溶加固地基抗震构造评估模型分析。采用莫尔—库仑理论,根据岩溶塌陷地质形成因素,计算岩溶顶板安全厚度的极限承载能力,分析岩溶顶板稳定性,由岩溶顶板抛物线拱力学模型,计算压力拱高度变化取值,完成岩溶顶板注浆加固机理研究,分析地震作用下的抗震构造可靠性,建立岩溶加固地基抗震构造评估模型。实验结果表明,所设计的地震作用下岩溶加固地基抗震构造评估模型,与传统相比所得到的评估范围更加广泛,使评估结果更加精准。由此可见,此模型更有效果。     

砌体建筑抗震设计及加固新方法

介绍了美国砌体建筑物地震评估及加固方面的新发展,以及美国新近推荐采用的基于使用功能的砌体抗震规范,并与中国目前采用多的层砌体房屋的抗震设计规范作比较,指出出砌体抗震设计及加固中,提高它的塑性变形能力与提高它的强度同样重要。     

砖石古塔抗震性能评估方法及抗震加固措施研究

为了提高砖石古塔的抗震性能,针对其地震反应特点,研究了砖石古塔的抗震薄弱部位、抗震性能评估方法、评价指标以及抗震加固措施。主要研究结论为:（1）提出了采用极限承载能力与层间位移角2个指标综合评估砖石古塔的抗震性能,并通过工程实例验证了该方法的有效性。（2）提出了对穿锚杆锁定内外钢带围箍和竖向贯穿钢筋为主,聚丙烯酸脂乳液砂浆裂缝注浆为辅的砖石古塔综合抗震加固措施。（3）砖石古塔塔底截面为承载能力抗震薄弱部位,抗拉能力不足是导致塔体破坏的主要原因。（4）地震作用下,砖石古塔随着塔体层数的增加,层间位移角增大,顶层塔体为变形能力薄弱部位。该研究结果可为砖石古塔的抗震性能评估与抗震加固提供参考。     

基于性能的既有钢筋混凝土建筑结构抗震评估与加固技术研究

根据我国现行的建筑结构抗震规范,无论是新建建筑结构的抗震设计还是既有建筑结构的抗震评估与加固,均通过小震弹性承载力计算 抗震延性构造措施来达到"小震不坏、中震可修、大震不倒"的抗震设防目标(对于不规则且具有明显薄弱部位的建筑结构还需要进行罕遇地震作用下的弹塑性层间变形验算)。对于抗震延性构造措施不满足现行规范的既有建筑结构的评估、改建、扩建,如果仅通过小震弹性的承载力计算,显然无法达到"大震不倒"的目标。本文通过引入国际上先进的基于性能的结构抗震思想,以结构层间位移和结构构件变形作为性能目标,从定量上解决了既有钢筋混凝土建筑结构的抗震评估与加固问题。     

山区桥梁的抗震概念设计

山区桥梁因为地形和施工条件等的限制,给设计带来很大的问题,使得结构不规则,影响了桥梁的抗震能力。且由于山地震动效应等复杂因素的影响,该类桥梁的抗震计算往往不能很好地反映真实的地震反应。概念设计通过长期积累的实际设计经验和理论研究的成果,从总体上把握设计的原则,是非常重要和有意义的。本文针对山区桥梁的特点,对山区桥梁的抗震概念设计方法进行了探讨。     

准东石油基地幼儿园抗震鉴定与加固

结合准东石油基地幼儿园的抗震鉴定与加固实例,在对原结构抗震措施鉴定和分析验算的基础上,介绍了房屋结构薄弱部位的加固做法。对类似项目的结构加固有一定的参考价值。     

能力谱方法在桥梁抗震性能评估中的应用研究

位移延性是桥梁抗震性能的重要指标之一,以Pushover分析为基础的能力谱方法能够考察结构在地震下的弹塑性位移响应,是抗震性能评估的一种有效手段.文中阐述了能力谱法的基本原理,说明了基于弹塑性反应谱的能力谱方法在求解性能点时不需要进行迭代计算;基于弹性设计反应谱建立了相对应的弹塑性反应谱,结合某实桥,将能力谱方法和增量动力分析方法进行了对比,并根据不同的地震基本烈度和场地土类型进行了抗震性能评估.分析认为,能力谱方法计算简便,对结构1阶振型的地震响应占主导时,具有较好的精度,并能够基于设计反应谱来考察结构的弹塑性抗震性能,可用于桥梁抗震性能的评估.     

桥梁限位器抗震设计方法研究

本文建立了两跨简支梁桥和五跨多跨刚架桥两结构模型，针对限位器的种类、刚度、强度、安装位置，输入地震动等进行了大量工况下的数值模拟研究。研究表明限位器与柱（框架）的刚度比在0.5-2之间较优。将现有的限位器设计方法应用于两算例结构，对现有限位器设计方法进行了比较研究。     

Stochastic analysis of the linear equivalent response of bridge piers with aseismic devices

The dynamic response of bridge piers with aseismic devices to earthquake excitation is evaluated by the stochastic equivalent linearization technique. The seismic acceleration is schematized through a Gaussian stationary random process. The pier is considered linear elastic, the span is idealized as a rigid mass, the restoring force of the device is represented through a non-linear differential model. The study of the complex modes of the linearized system gives an interpretation of the mechanical behaviour, leads to a formally elementary solution and highlights some phenomena which are typical of the hysteretic systems, particularly of those marked by weak hardening. Even though the solution is limited to the stationary field, it brings out several noteworthy considerations about the effective non stationary behaviour of the structure. Copyright © 1999 John Wiley & Sons, Ltd.     

Fuzzy optimum design of aseismic structures

It was pointed out in our previous paper that there exists a vast amount of fuzzy information in both objective and constraint functions of optimum design of structures. Then the idea of fuzzy optimum design of structures was first proposed and the problem with fuzzy allowable intervals of the physical variables (structural responses and sizes) could be solved via the α-level cut approach. In this paper, the procedure of fuzzy optimum design of aseismic structures is further developed. For this purpose, the concepts and definitions of fuzzy predictive earthquake intensity, fuzzy response spectrum and fuzzy structural response are given. A solution of the programming problems with generalized fuzzy constraints (including both fuzzy constraint functions and their fuzzy allowable intervals) is put forward; one of its special cases is the χ-level cut solution in Reference 1. The satisfaction degree of a fuzzy constraint function to its fuzzy allowable interval is defined, by which the problem considered is transformed into a series of non-fuzzy programmings. Then, a series of optimum points can be obtained which make up the solution of the fuzzy programming. As the solution of fuzzy programming contains not one but a series of optimum points, a two-step approach is presented to the fuzzy optimum design of aseismic structures. The first step is to find out the set of minimum cost design points corresponding to different design levels. In the second step, both construction cost and earthquake-caused loss expectation in the service life of the structure are traded off to find the optimum design level as well as a corresponding optimum design scheme.     

现有建筑抗震能力评估

本文提出了个一个用超强率求建筑物地震破坏概率的方法,并评估了现有建筑的抗震能力。为进一步分析地震灾害,文中给出了现有建筑中典型建筑的地震屈服加速度和对应于不同破坏状态的延性率中值,最后讨论了设防中的其他问题并提出了改进抗震设计的建议。     

Cyclic performance and simplified pushover analyses of precast segmental concrete bridge columns with circular section

In recent years, precast segmental concrete bridge columns became prevalent because of the benefits of accelerated construction, low environmental impact, high quality and low life cycle costs. The lack of a detailed configuration and appropriate design procedure to ensure a comparable performance with monolithic construction has impeded this structural system from being widely used in areas of high seismicity. In this study, precast segmental bridge column cyclic loading tests were conducted to investigate the performance of unbonded post-tensioned segmental bridge columns. One monolithic and two precast segmental columns were tested. The precast segmental column exhibited minor damage and small residual displacement after the maximum 7% cyclic drift; energy dissipation (ED) can be enhanced byadding ED bars. The experimental results were modeled by a simplified pushover method (SPOM), as well as a fiber model (FIBM) finite element method. Forty-five cases of columns with different aspect ratios, axial load ratios and ED bar ratios were analyzed with the SPOM and FIBM, respectively. Using these parametric results, a simplified design method was suggested by regressive analysis. Satisfactory correlation was found between the experimental results and the simplified design method for precast segmental columns with different design parameters.     

医院住院部大楼抗震性能评价

以某医院住院部大楼为例进行结构抗震性能评价，首先分析了场址的地震环境，开展了地震危险性分析工作，合成了不同地震危险水平下的地震动加速度时程。进而，通过对结构的模型简化，应用时程分析方法分析结构的抗震性能，得出了一些对其改造加固有意义的结论。     

保温夹心节能墙体抗震性能分析

本文采用三维有限元方法对夹心墙体进行抗震性能分析，通过计算结果与实验结果对比，确定合理的计算模型，对夹心墙体进行数值模拟计算、分析了墙体抗震性能、内外叶墙体参与工作情况及应力分布，研究了拉接筋的拉接率对墙体影响．     

基于遗传算法的抗震结构智能优化设计

本文给出了基于损伤性能的抗震结构最小造价设计数学模型,并分析了其特点和难点,然后把优化的数学模型转化为人工进化模型,用遗传算法实现了抗震结构的智能优化设计。研究结果表明,遗传算法是实现结构智能设计的有效途径,具有广阔的应用前景。