Studies Of The Seismic Fortification Principle Based On The Earthquake Damage Matrix

Earthquake is one of the serious natural disasters in the world which can make great harm to the human. Resisting of earthquake and decrease of disasters become more important to the human go with the advance of international economy and science increasingly. The seismic fortification criteria shows consequence in aseismic designing for it connects to the capability of the aseismic capability structure directly. The design earthquake levels regulated in Chinese seismic code which has three levels of fortification and two phases of designing estimates and controls the inelastic deformation in the second level and the third level intensity to ensure the capability of the aseismic structure by accounting the elastic response in the first level intensity. But this method doesn't always ensure the capability of the aseismic structure in the second level and the third level intensity.This paper studies about the aseismic structural reliability at the recent seismic fortification criteria level regulated in Chinese seismic code and the optimal seismic fortification criteria. In this paper, different damage indexes and partition of damage grades are summed up and compared. Three-level performance objective of seismic damage is expatiated; the connection between partition of damage grades and three-level performance objective of seismic damage is brought forward; and some representational damage data are analyzed according to the connection. historical Chinese seismic codes are reviewed, the method of three-level aseismic designing reliability analyse are brought forward, the aseismic reliability of the Chinese existing structures is analyzed, and the result shows that the aseismic capability of Chinese existing structures is rich for the first level intensity,but poor for the second level and the third level intensity.The aseismic reliabilities of the Chinese existing structures are analyzed at the three seismic fortification levels respectively. The result shows that the aseismic reliabilities of the structures are poor if the seismic fortification criteria based the first level, the damage will beyond the expectation in the second level and the third level intensity. And the aseismic reliabilities of the structures are rich if the seismic fortification criteria based the third level, the damage will below the expectation in the first level and the second level intensity, but it will waste great lot of money. This paper suggests that the seismic fortification criteria based the second level is optimal considering the aseismic reliability and engineering cost.