Safety&Economic Analysis For Seismic Appraiser And Strengthening Of Special Structures

The revision edition of the standard for seismic appraiser of special structures differs from the previous edition in many aspects, this paper grandly compares their differences in several aspects, based which the progress of the revision edition standard on seismic fortification target and seismic design concept is pointed out. This paper figures that the biggest improvements of the revision edition standard are adjusting the seismic influence coefficient and classifying the appraisal method according to the follow-up service years. Based on these two improvements, the security of the new standard and the economic effectiveness of the seismic strengthening project are discussed.In the part of comparing the two editions, this paper separately analyzes their main differences from applicable scope, the objective of seismic appraiser, seismic appraisal methods, seismic checking calculation, evaluation index of the appraisal results etc. Further on, it points out that the base of these differences is the development of seismic fortification concept and objects in civil engineering.In the part of security analysis, the relation between return period of earthquake and probability of exceedance,design reference period are established according to the assumption that the earthquake frequency have coincidence with poisson distribution, it also point out that the seismic intensity of different follow-up service years can be confirmed by the equal exceeding probability principle, Further on,according to the known relation of the minor, moderate and major earthquake, the relation formula between the seismic intensity and return period can be established by Second item interpolation. Through above analysis, the adjusting value of the seismic influence coefficient under different service years can be deduced, with which the value in the revision standard are compared, then the security conclusion of the standard is draw.In the part of security economic effectiveness analysis, objectivistic criterion is to minimize the sum of seismic strengthening investment and expected disaster loss, the diversity between the economic effectiveness analysis of this paper and traditional ones is analyzed, then the paper come up with the annual minimum cost criterion as the evaluation criterion of this paper. In the process of analyzing the Simple formula to calculate the seismic strengthening investment is established, meanwhile the formula to calculate the expected earthquake disaster loss of monolithic special structures is draw out basing on the Seismic vulnerability matrix and the loss ratio.