Seismic simulation of a complex structure is conducted by a distributed substructure online hybrid test system.In this system

substructures are partitioned according to the structure characteristics and treated by different finite element programs.Each substructure is encapsulated.And only the displacements and forces at the boundaries are exchanged between substructures via standard Input/Output（I/O）interfaces.The equilibrium and compatibility is searched and guaranteed by aquasi-Newton procedure.The seismic behavior of an SRC（Steel encased Reinforced Concrete）structure with a steel tower on the top is obtained using this system.The entire structure is divided into three substructures

i.e.

the SRC frame

the first story of tower

and the upper part of tower.The SRC frame is analyzed by OpenSees that has a great capacity to analyze composite SRC members.The first story of tower is taken as the experimental part

because it sustains largest deformations and subsequent structural damage.The upper part of tower is analyzed by ABAQUS that is strong at simulating steel braced frames involving large geometric nonlinearity.The result demonstrates that nonlinearities of each numerical substructure are accurately simulated by the respective FEM program.