底部框架砖房地震倒塌调查与分析

Collapse investigation and analysis of RC frame supported masonry structures under the earthquake

摘要:

为研究底框结构地震后的倒塌模式与废墟特征，预测存活空间分布规律，通过实际震害调查、数值模拟及振动台试验，对底框结构地震倒塌后废墟特征及存活空间分布规律进行研究.首先依据目前的实际震害资料，发现底框结构典型的三类地震倒塌模式(底框层倒塌、过渡层倒塌、整体倒塌)中底框层倒塌是相对概率较高的倒塌模式.在此基础上分析倒塌后底框结构的废墟形式，主要为“骨断筋连型”与“松散型”两类，并研究认为“骨断筋连型”废墟存活空间相对较大，但是震后拆除救援困难，而存活空间主要分布在背离倾覆一侧.同时相对于底框层，顶层有更大的存活空间；“松散型”废墟存活空间较小，但相对震后易于救援，在背向倒塌方向一侧，墙体较少的房间内靠近柱梁位置，在梁下会有一定的存活空间.之后建立了基于有限元软件ANSYS-LSDYNA的底框结构废墟研究数值模型，并阐述了模拟方法，而底框结构震害特征、振动台试验与数值分析结果的相似证明本文废墟研究数值建模方法的正确性，认为背向倒塌一侧且墙体较少部位人员存活空间较大.本文研究可为震后快速救援定位提供依据，并对人员逃生提供建议.

Abstract:

To investigate ruin characteristic and rules of survival space in the RC frame supported masonry structures after earthquake, seismic investigation was carried out and FEM analysis and shaking table tests were conducted. The three main collapse modes were summarized (the collapses of frame floor, transfer floor and overall structure) based on seismic investigation. The result shows that collapse of frame floor is the most common type. The connection mode and the loose mode are the two main ruin modes. The connection mode owns more survival space and is difficult for rescue, and more survival space is on the reverse direction of collapse. The top floor of frame structure has more survival spaces than the bottom floor. The loose mode owns little survival space and is easier for rescue than the connection mode. There is a certain degree of survival space on the less wall position near the beam-column, and under the beam, which lies in the reverse direction of collapse. The FEM collapse analysis of frame floor was conducted, which was based on ANSYS-LSDYNA, and the results were verified by comparing with the results of seismic investigation and shaking table tests. It shows that there is more survival space on the position of reverse direction of collapse with fewer walls. It contributes to locate the rescue position quickly after earthquake and provides important advises for evacuation.