Mechanical analysis of structures under fire can be divided into two levels:the junior is fire analysis of separated member

such as mechanical analysis of beam

column or slab under fire

and the further is whole structure under fire

such as structural progressive collapse under fire.Whole structure fire test is more accordant with practical structures

but also more expensive compared with separated member fire test.Thus

hybrid fire test was proposed by Mostafaei.This new test method combines fire test with numerical analysis

which means the separated member will still be tested in furnace

while the remaining structure will be analyzed in computer

with synchronization of certain items at certain time or temperature.Theoretically

the mechanical response of whole structure under fire will be the same with that measured in hybrid fire test

if the forces and displacements are the same between separated member in fire test and remaining structure in computer during the fire.However

the loading condition and boundary condition cannot be adjusted at any time during fire

so those variables will be changed in certain time intervals or temperature intervals.To validate and pre-realize hybrid fire test

the separated column fire test is simulated by numerical software

then an interactive procedure between separated column and remaining structure will be executed.The hybrid fire test results are in good accordance with whole structures response under fire

which shows a convenient and cheap alternative way to substitute whole structure fire test.