The weakening of web sections by vertical pre-stressed ducts on two actual pre-stressed concrete continunous box girder bridges is analyzed.

Study on the vertical prestress loss of the prestress concrete box girder bridge web;

Test of vertical prestress loss and analysis research on it;

The vertical prestress applied to webs of concrete box girder is studied.

In this paper,starting from analysis of the sensitivity of slant box beam web cracks to vertical pre-stress,the dynamic mechanism of the effective reduction in main web pulling stress by vertical pre-stress is explained.

The distribution of ring pre-stress, anchoring steel beam and pre-stress, vertical pre-stress of the anchoring zone of the main tower in Songhuajiang cable stayed bridge are introduced and the corresponding construction technologies are clarified in the paper.

The vertical pre-stressed reinforcement installed in the pre-stressed concrete continuous (rigid frame) box beam bridge is to decrease and control the main tension stress of the web and to prevent the creaking.

Based on the long-term field measurement of vertical prestress losses in the box girder of a long-span PC continuous bridge,a detailed analysis of the loss of the vertical prestressing is conducted.