Abstract:Rock-like materials have high compressive strength,but low tensile one. Testing study is made on a express highway for improving these material characteristics to meet the engineering requirement. The prestressed concrete girder is pulled,and three types of load,that is,the fixed load in the middle of the girder,well-distributed and point loads on the girder,are exerted. The working characteristics of prestressed concrete girder under the states of elasto-placticity are discussed. Experience for the design of prestressed concrete girder has been accumulated and mechanical behaviors of rock-like materials have been investigated.