Basic Studies On Optimization Method Of Seismic Fortification Criterion Of Buildings

From the work of earthquake preparedness and disaster reduction of the world we can see that many countries strengthen seismic capacity of the buildings and improve the capacity of emergency response and command in order to prepare for the earthquake. Because of our economic level we can not increase the capital input for earthquake preparedness unlimitedly. In order to solve the balance problem on high seismic fortification demand and less money there should be a method which can find the least capital input on the base of social acceptable security level.The purport of this paper is finding the optimization method of seismic fortification criterion of buildings which can determine the optimal seismic fortification criterion in the seismic design. This optimization method can decrease the unessential input for seismic fortification and increase the essential fortification for the buildings. Simultaneous the optimal fortification acceleration of building group or city can be determined.The principal of the seismic design can be expressed by the following formula which represent the least total input: S=capital input for seismic fortification and loss because of earthquake, namely S ( A_d)= C ( A_d )+ L(Ad) =min. where the symbol S ( A_d) denotes the total input of seismic fortification when the earthquake accelerate is A_d ;the symbol C (A_d) denotes the accessorial initial cost for seismic fortification when the earthquake acceleration is A_d ; the Symbol L ( A_d)denotes the earthquake economic losses when the earthquake acceleration is A_d . The A_d calculated by the above formula is determined only economic factors considered. Simultaneously, make sure that earthquake death rate which is expressed by the symbolRC and calculated by the economic optimal fortification acceleration A_d is less than the socially acceptable rate level for earthquake death which is expressed by the symbol RC c. If not, the near-optimum economic fortification acceleration should be calculated until RC of A_d satisfies the inequality of RC≤RC c.The steps of this paper are as follows: the probability density function of earthquake acceleration according to the seismic hazard analysis; the determination of damage probability model; the economic loss evaluation and initial cost evaluation; the determination of the method of calculating earthquake death rate and socially acceptable rate level for earthquake death. After the above steps finished the optimal fortification acceleration can be obtained by the formula of S ( A_d)= C ( A_d )+ L(Ad).