Abstract: To deal with the problem that the all18aerodynamic derivatives‚especially part of cross and lateral aerodynamic derivatives‚can not be obtained from the wind tunnel experiment at present‚a hybrid model of self-excited forces for the buffeting analysis of long-span bridges was presented．In this model‚the direct self-ex-cited forces are obtained by Y．K．Lin’s model and only a linear filter is used to simulate unsteady self-excited forces‚while the cross self-excited forces are extracted from the quas- i steady aerodynamic force model via Taylor expansion．It is a good choice to adopt the hybrid model proposed here when not all the aerodynamic derivatives‚especially the cross aerodynamic derivatives‚can be obtained from the wind tunnel experiment．At last‚an illustrative example was given about the Yamen Bridge‚which shows excellent agreement between the calculated and experimental results of wind tunnel adopting the aerodynamic elastic turbulence-field model for the whole bridge．

Key words:  long-span bridge, buffeting analysis, time-domain method, hybrid self-excited force model