The results suggest that 20% of moment redistribution at the internal support could be gained in the local buckling design of continuous composite beams with the non compact cross section(class 3).

The analytical results show that failure of members with low slenderness ratio tends to cause local buckling,while failure of members with high slenderness ratio will cause flexural buckling.

The results show that the failure mode of extended endplate connection is the large deformation of bending taking place initially in the tensile zone of endplate and column flange,and then the local buckling of compressive zone in connection causes the loss of carrying load.

In connection with the characteristic of this structure, the stability and buckling styles (overall buckling and local buckling) are researched in deta.

Probability method was used to solve partial failure probability,which verifies the feasibility of gradual failure probability analysis.

The thermal viscoplastic constitutive equation was established by the impact compression and the impact shearing tests by the split Hopkinson pressure bar(SHPB),the process of local plastic instability at higher strain rates was analyzed,the criterion of plastic instability was obtained,and the nature of the high strain rate sensitivity for local plastic instability was revealed.