Analysis Of Seismic Vulnerability Of Reinforced Concrete Continuous Beam Bridge Pier Columns

Destructive earthquakes have happened many times in our country since1949.In these earthquakes, many bridges have been destroyed to different degrees.Meanwhile, it is not difficult to find out that bridge is the most vulnerable part in trafficsystem. If the bridge is impassable, it will bring many difficulties for earthquake reliefwork. Therefore, to improve a city’s ability in emergency and in earthquake relief, it isurgent for us to estimate the vulnerability of a bridge when an earthquake happens. Theprocess may be slow for that we have no accurate research method in bridgevulnerability till now, although we have been excellent in the research of buildingstructure. Even so, we urgently need to estimate the vulnerability of bridges which areaimed at resisting earthquake.Through the description of several destructive earthquakes in our history and themethods in researching bridge vulnerability, this thesis brings out the definition ofseismic vulnerability and compares the advantages and disadvantages of each method.By describing the method and process of building theoretical vulnerability curve, thisthesis gives us the framework of the whole research steps. According to the knowledgeof the traits of seismic wave and the requirements of wave choosing, this thesis selectssome eligible documentary seismic wave. It also systematically introduces thedefinition of pier column damage criterion on the basis of destruction criterion. Afterdefining the constitutive model of the material, the properties of the pier column’scross-section will be evaluated by bending-moment curves analysis through a softwarecalled MIDAS/Civil. The result of bending-moment curves analysis then helps tocalculate the critical value of different damage stage.After reading many datum in bridge vulnerability, combining the damage traitsof previous cases, and referring to Hwang and Liu Jingbo’s reliability method, thisthesis studies bridge’s vulnerability in earthquakes. Through the non-linear dynamicanalysis of continuous girder brides, this thesis builds up the structure-reactionprobability functions, works out the exceedance probability, draws out the vulnerabilitycurves which sets PGA as its variables and evaluates the impact of pier column’s upperstructure quality and cross-section reinforcement ratio on bridge vulnerability.