人行激励对钢筋混凝土框架教学楼抗震性能的影响

发布时间：2018-01-20 08:47

本文关键词： 抗震性能框架结构教学楼动力特性测试人行激励增量动力分析　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：传统的框架结构抗震性能分析基本上都忽略了人对结构的影响,或是把人当做活荷载或者是附加质量,而这些作法均不能准确的反映人对结构抗震性能的影响。为了研究人行激励对钢筋混凝土框架结构教学楼抗震性能的影响,本文先用脉动法对某框架教学楼进行现场测量,从而得到人对该结构动力特性的影响,进而分析出其对结构抗震性能的影响。具体步骤及内容为:(1)运用脉动法现场测试教学楼在三种工况(静止人荷载工况、空载工况、人行激励工况)下的动力特性数据。整个测试过程进行了9组测试,每种工况测试了三组数据;(2)运用MATLAB对该教学楼的脉动测试数据进行分析,分析过程包括:1)对信号进行预处理以消除干扰和噪声;2)对信号进行滤波和重采样;3)对信号进行自谱和互谱分析以得到结构的自振周期和振型;4)运用NEx T法和STD法对数据进行阻尼识别。分析结果发现,三种工况下,结构的频率变化不大,微小的变化趋势为静止人荷载工况下频率稍微低于其他两种工况,人行激励工况下频率在一个较小的范围内变化,最终加权人行激励下结构的频率最大。静止人荷载工况下结构阻尼比最大,人行激励工况次之,空载工况结构阻尼比最小;(3)运用增量动力分析法分析评估该教学楼在三种工况下的抗震性能。具体过程如下:1)在PERFORM-3D中建立该结构的有限元模型,并将分析得到的三种工况的动力特性参数分别输入模型;2)以单条地震动为例详细介绍了对该结构进行IDA分析的过程;3)选择数条地震动记录,用同样的方法对结构进行IDA分析,得到数条IDA曲线组成的IDA曲线簇;4)对IDA曲线簇进行统计分析得到每种工况16%、50%、84%分位的IDA曲线,并对曲线进行比较。结果发现:在地震动强度较小时,三种工况下结构的IDA曲线几乎重合,此时结构抗震性能几乎没有变化;但随着地震动强度的增加,IDA曲线有了较明显的分开,空载工况由于阻尼比较小结构率先进入各个性能状态,人行激励工况次之,静止人荷载工况最后。可见,在有人的建筑中,人的走动对结构抗震性能具有不利的影响,这种影响在地震动强度较小时几乎可以忽略,但随着地震动强度的增加,这种影响也越来越大。
[Abstract]:In the traditional seismic performance analysis of frame structures, the influence of human on the structure is ignored, or the people are regarded as living load or additional mass. In order to study the effect of pedestrian excitation on the seismic behavior of reinforced concrete frame building, these methods can not accurately reflect the effect of human being on the seismic behavior of the structure. In this paper, the pulsation method is used to measure the dynamic characteristics of a frame building, and the effect of human on the dynamic characteristics of the structure is obtained. The concrete steps and contents are: 1) using pulsation method to test the teaching building under three conditions (static load condition, no-load condition). Dynamic characteristic data under the excitation condition of pedestrian bank. Nine groups of tests were carried out in the whole test process, and three groups of data were tested under each condition. 2) using MATLAB to analyze the pulsation test data of the teaching building, the analysis process includes: 1) preprocessing the signal to eliminate the interference and noise; 2) filtering and resampling of signals; 3) the self-spectrum and cross-spectrum analysis are carried out to obtain the natural vibration period and mode shape of the structure. 4) NEx T method and STD method are used to identify the damping of the data. The results show that the frequency of the structure does not change much under the three conditions. The slight change trend is that the frequency under static loading condition is slightly lower than the other two conditions, and the frequency changes in a small range under pedestrian excitation condition. The structure frequency is the largest under the ultimate weighted pedestrian excitation. The damping ratio of the structure under static load is the largest, followed by the pedestrian excitation, and the structure damping ratio under no-load condition is the smallest. 3) using incremental dynamic analysis method to analyze and evaluate the seismic performance of the teaching building under three working conditions. The concrete process is as follows: 1) the finite element model of the structure is established in PERFORM-3D. The dynamic characteristic parameters of the three conditions are input into the model respectively. 2) taking a single seismic motion as an example, the process of IDA analysis of the structure is introduced in detail. 3) selecting several ground motion records and using the same method to analyze the structure by IDA, the cluster of IDA curves composed of several IDA curves is obtained. 4) through statistical analysis of IDA curve cluster, the IDA curves of 1650 and 84 quartile of each working condition are obtained, and the curves are compared. The results show that the intensity of ground motion is small. The IDA curves of the structures almost coincide with each other under three working conditions, and the seismic behavior of the structures is almost unchanged. But with the increase of the intensity of ground motion, the curve of IDA is obviously separated. Because of the small damping of the structure, the no-load condition is the first to enter each performance state, and the pedestrian excitation mode is the second. Finally, it can be seen that the movement of people has a negative impact on the seismic performance of the structure in some buildings, which can be almost ignored in the low intensity of ground motion. However, with the increase of the intensity of ground motion, this effect is becoming more and more serious.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU375.4;TU352.11

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