Multi-hazard Vulnerability Analysis Of Existing Buildings

Under the impetus of the National 12 th five-year plan, the transformation of existing buildings has become an important trend of the current Chinese construction field. Most of the existing buildings built in the early development of the construction industry in our country, when the seismic behavior and wind performance are took less consideration for structures. Most of the buildings have been aging after using for 50 years, and their safety, durability, energy efficiency, comfort, environmental protection and other aspects are difficult to meet people's needs at the present stage, so it is imminent to reconstruct the existing buildings.This study focus on the disaster vulnerability analysis of the existing buildings firstly, and then assess the performance of existing buildings under the disaster, at last repair and reinforce the structure based on the assessment. This paper summarizes the current situation of vulnerability analysis, analysis methods and their advantages and disadvantages at home and abroad, then put forward a new vulnerability analysis method. Main body consists of three parts. The first part that define the damage index for structures, and determine the relationship between the damage index and the damage state. The second part is the disaster vulnerability analysis for structures, including seismic vulnerability analysis, wind vulnerability analysis, combine wind with seismic vulnerability analysis, the third part that reinforce the existing buildings with dampers according to disaster vulnerability analysis results.The main contents are as followsFirst and foremost,gain the weight coefficient of each component in the overall structure by defining the weight. The method uses damage value multiply member weight coefficient define damage index, then add the damage index of all components get the overall damage index, and define the overall damage index for evaluating structural vulnerability index parameter norm.Secondly,select typical existing buildings in our country, build finite element model in structural analysis software sap2000, input seismic waves and wind speed time curve into the structure, carry on the nonlinear dynamic time history analysis, output displacement angle of each column, then gain the overall damage index and the damage value of monomer components by calculating.Identify different failure state exceedance probability by the overall damage index, draw vulnerability curves finally.Last but not the least,establish a reinforced concrete structural model, verify the method this paper proposed whether it is suitable for reinforced concrete structures, get on seismic vulnerability analysis, gain the structural weaknesses and reinforce the weaknesses in the structure. Vibration damper is a new reinforcement technology, which is simple practical and has a good effect. Currently damper has been widely used on construction, but the election for the position where set the dampers has to be studied. The vulnerability analysis method based on component weighting coefficient can be ordering the damage of the component, according to members' damage choose the serious damage position to set steel type vibration damper for reinforcing and then get seismic vulnerability analysis on the damping structure, at last draw vulnerability curve of structure with dampers. By comparing the two kinds of vulnerability curves, demonstrate the effectiveness of the position where set the dampers.