Static Load Test Method and Performance of Rail Transit Pre-tensioned Precast U-shaped Beam

Relevant test standards were not proposed for prefabricated U-shaped beams in the rail transit field at present. For batch prefabricated U-shaped beams,the static load test should be carried out at a certain sampling frequency to test and evaluate the mechanical properties. A new static test method is proposed which can be applied to multi span precast U-shaped beam. Reaction frame loading was used and a loading principle was recommended of which the loading bending moment is equal to the maximum design bending moment and the loading shear is approximately equal to the maximum design shear at the same time. The prefabricated U-shaped beam of Shenzhen urban rail transit line 6project was taken as an example,the test scheme is designed,which can ensure the load efficiency of 1. 0 and the shear load efficiency of 0. 81 ～ 0. 95. In order to avoid premature lateral damage of the bed plate,the increased load is loaded through the top jack of the web after the loading moment exceeding 1 times the design value,and the load force of the bed plate is maintained. The test results show that the test method of pre-tension U-shaped beam is economical and reasonable,which can provide valuable references for static load test of prefabricated U-shaped beam in the future.