Influence Of Design And Construction Deviation On The Behaviors Of P.C. Voided Slabs

A large number of prestressed concrete bridges, 'which are the most popular bridge structures, around the world have been built in our country. However, with the rapid development of the traffic construction, the cracks of the prestressed concrete bridge appear as well. The thesis focuses on the post-tensioned prestressed void slab bridge, where the longitudinal crack a long the prestressed wire strand at the bottom of the girder are found during the operation, with 30m span in Chongqing and does the following research:1. Based on the analysis and the research of the mechanic performance, and the development of the cracks of the test beam under the dead and cycle load, the deviation between the design and the construction is pointed out as the main reason of the abnormal phenomenon of the test bean during its phases of construction and use.2. According to the analysis of the cracking moment of the test girder under the cycle load, the formation, used to calculate the number of second cracking moment considering the effect of the cycle load, is provided. It has been proved satisfied to be consistent with test results.3. On the basis of the numerical analysis of the mechanic performance at the phases of construction and use, the shear resistance of the prestressed concrete voided slab with longitudinal cracks is lower, compared to the ideal situation without damage.4. With the help of the fatigue analysis in the Fatigue model of ANSYS, the results show the fatigue life of the girder is decreased from 2 millions to 180.34 thousands because of the existence of the longitudinal cracks.5. Based on the test research and the theory analysis, the reasons why the cracks appear are summarized, which can be a valuable references to the design and the construction of the similar prestressed concrete bridge.