Design Research Of Downstream Traffic Bridge In The Dagangshan Hydroelectric Dam

As a good bridge-type composite indicator, prestressed concrete continuous rigid frame bridge was widely used in recent years in Chinese transport construction. Such bridge was developed from both the continuous prestressed concrete T-beams and the rigid frame, and become a combination structure. Also, the good characture in the ordinary continuous beams and T-shaped rigid frame was carried on. As the main bridge across the deep valley type, the continuous rigid bridge was applied to a large number of various regions with the development of the transport construction in Chinese mountainous regions.Based on continuous rigid frame bridge downstream engineering examples to the Dagangshan dam, continuous rigid frame bridge design process was introuced. Then the static analysis was carried out. The main contents include:1. The basic design principles ws described, and the bridge computational model was built to analyze the static characteristics of the bridge.2. Reasons of deflection in the rigid frame bridge were analysised.3. According to the results of the analysis, some useful conclusions were acquired, such as:(1) By imposeing the different sizes of prestressing degree in structure, the factor of the creep effect on the direction of impact of the mid-span deflection factor is the structure of prestressed degree.(2) With the main beam concrete grade increases, the elastic modulus increased more than improve the creep due to the concrete grade, its creep value slightly decreases with the concrete grade increases.(3)The top thrust applied to both ends of the mid-span close before the main beam can be offset by the main beam midspan creep and shrinkage caused by the displacement, the beam axial shortening decreases can be significantly improved by the force of the main pier.(4) With the increase of the prestressing tension age, the creep effect is slightly reduced.