Design of Anchorage-Type Abutment of Danjiangkou Reservoir Bridge
The Danjiangkou Reservoir Bridge is a two-pylon,hybrid girder cable-stayed bridge with a main span of 760 m and double planes of stay cables.The abutments No.1 and No.4 are anchorage-type structures to accommodate the pairs of earth-anchored stay cables.The anchorage-type abutments are hollow box structures that are composed of bottom slabs,walls,cap slabs as well as the main girder in the anchor section and the abutment foundation.Measuring 45.8 m in total length and 31.6 m in top width,the rectangular-spread-foundation-supported abutment comprises 18 cells.To achieve smooth force transfer,the transition between the abutment and main girder is designed as a ribbed wall structure.To reduce the integral stress level and improve the anti-cracking performance of the abutment,the walls of the abutment are fitted with vertical prestressing tendons.To enhance the anti-sliding stability of the abutment No.1,the walls are equipped with CFRP anchor rods that are socketed in the moderately-decomposed bedrock.The mechanical property and anti-sliding stability of the anchorage-type abutment were verified by numerical simulation.It is demonstrated that the overall stress distribution in the abutment is even,and stress transition in the joint section of the abutment and main girder is smooth.The longitudinal and transverse walls of the abutment are mainly in compression,with a degree of compressive stress margin in the key locations.After equipped with CFRP anchor rods,the anti-sliding stability coefficient of the abutment No.1 is improved by 20%.