The Model Test Study On The Existing Stress Detection Of Prestressed Hollow Slab Bridges Based On The Stress Releasing Method

the existing stress of the Prestressed concrete bridges is one of the key metric reflected the state of the technology. Because of prestress loss, concrete shrinkage and creep, structural damage,etc, It maybe very different between expected and actual values. It may affect the service function of bridges, may even lead to security incidents. The existing stress inspection of bridges is still a difficult technical problem at present. In this paper, based on lots of documents at home and abroad, Using stress-releasing method to analys the existing prestress of the hollow slab bridges.it not only analyzed by the finite element calcution,but tested by the model of interior. The main research working as follows:1.For a prestressed concrete hollow slab bridges,which span is 20 metres, modeling a three-dimensional solid finite element model, which simulated concrete stress-release method, the arctile maily analysised different sizes of ring -holes, square-holes and horizontal grooves, and minimum cutting depth that the surface stress release to zero .2. For a length of 10 m prestressed hollow slab bridge, based on the stress releasing method of steel bars, modeling the three-dimensional solid finite element for numerical calculation, studing the stress of steel-bars change while one of these tendons was total lossed the prestress , exploring and proving the feasibility of this method in theory.3. For two pieces of rectangular reinforced concrete slab,which size is 1.5m×2.0m×0.2m, no any prestress,to do concrete- cutting, steel-cutting test. We Studied lot's of effect factors about concrete and steel-bar stress-realeasing methods,got many practical conclusion,that's the basis of the test about the structure of the existing stress.4. For a length of 10m prestressed concrete hollow slab model, respectively the test of the stress-realeasing of concrete and steel bars.studing for those aspects of stress-realeasing of concrete and steel bars, at last concluded that"stress-realeasing of steel bars is better, and its accuracy can reach 90% above".