Study On Typical Seismic Collapse Pattern Of RC Frame Structure

All previous destructive earthquakes, both domestic and overseas, indicate that thecollapse of structure is the main factor leading to a large quantity of casualties andproperty losses. It is our aim all along to diminish the casualty and property loss understrong earthquake to the fullest extent. Therefore, on one hand, scientific researchers tryto improve the structures’ ability in meizoseismal area by studying on the collapsemechanism of structures. On the other hand, by investigating ruins of different fallendown structures, scientific researchers try to accomplish rapid rescue in accordance withdifferent structure types. Traditionally, the RC frame structure is widely considered tohave a favorable earthquake-resistance capability, while seismic damage survey ofseveral strong earthquakes such as Wenchuan Earthquake indicates that this kind ofstructure has an insufficiency of earthquake-resistance capability and a high collapseratio. The actual seismic damage indicates that the pattern of extensive destruction offrame columns causing the collapse of structure is the most frequent. In this collapsemodel, the first story or bottom stories completely collapse. This paper mainly studieson this collapse pattern of RC frame structure. By vibration testing the collapse of astructure, this paper analyzes the process and mechanism of the collapse, deduces thecritical collapse angle, and studies the stability of the space of survival formed bycollapse ruins. The main work includes four aspects as follows.1. In order to study the process and mechanism of the typical collapse of RC framestructure under strong earthquake, researchers set the Yushu Armed Police DetachmentSecond Squadron barracks as an archetype, design a testing model of1to5scale, andvibration test the collapse. The researcher studies the collapse process of RC framestructure by the test, and figures out the critical collapse angle of the testing model byuse of image cognition.2. Give a particular analysis of the causes, process and mechanism of the collapseby the collapse test. In the collapse test, according to whether the structure has obviousvertical displacement, the researcher classifies the collapse process into two phases:damage and collapse, and analyzes the factors that influence the structure’s collapse.Since the displacement angle between stories caused by earthquake is a controllingfactor to influence the structure’s collapse, this paper deduces the formulas of thecritical collapse angle of RC frame structure and discusses this formula.3. With the large quantities and widespread damaged form that first story collapseand uppers slope, the researcher particularly analyzes the stability issue of the space ofsurvival under aftershock and deduces the stability assessment formulas of this slopingstructure under aftershock combined with some seismic damage examples and based onsome hypotheses.