The thinking on engineering seismic design

Seismic design codes are generalized from theory research and practice of earthquake engineering,meanwhile they should be improved with the deepening on the earthquake engineering research and science progress.Some views and opinions about seismic design,such as aseismic concepts,requirement for fortification earthquake,structural analysis,constructional measure for earthquake resistance,are proposed.The meanings of earthquake intensity should be understood according to its different application conditions.It is tried for the seismic design to put probability into the earthquake intensity,but no easy to its application.The goals of earthquake fortification are to reduce the damage of building,avoid human casualties and alleviate economic loss.The object of the earthquake fortification in a zone should be earthquake fortification intensity.The site condition should be considered into the fortification intensity of engineering seismic design.It is reasonable to put the importance modified coefficient and structural coefficient into seismic design based on elastic response spectrum.The importance modified coefficient and structural coefficient are not generally relative to earthquake arose probability.It is no necessary to add many earthquake time histories to structural analysis under frequently occurred earthquake.The accurate of earthquake action is limited,so it is necessary to adopt constructional measure for the earthquake resistance besides structural analysis.The earthquake over the fortification intensity is a risk problem.