| With the rapid development of Chinese social economy in recent years,the contradiction between transportation needs and load capacity of existing bridges becomes more and more prominent due to the quickly increasing traffic flow and vehicle axle load.Affected by some harmful factors such as frequent overloaded vehicles,design defect,construction quality problem,environmental erosion,et al,the number of damaged or dangerous bridges gradually increased and quite a few of them need to be strengthened.The strengthening method study of pre-stressed hollow core concrete slabs is of great significance for transportation safety and sustainable development of highway transportation construction in China.In this paper,the 16m pretensioned prestressed concrete hollow slab girder with 20 years of service is taken as the research object,in order to research the effect of two kinds of reinforcement schemes-planting bar in webs and concrete-filled in hollow core slabs-to pre-stressed hollow core concrete slabs with pretensioning method,load test of test beams were done.Test beams carried on the design load according to "Standard methods for test of concrete structures"(GB/T 50152-2012),and the deflection value and stress value of the key sections were tested in the process of loading stress.They were compared with former strengthening data,and the shear properties of reinforced hollow slabs was analyzed.Then,finite element models were built according to different reinforcement schemes,the change characteristics of bearing capacity of test beams were carried out and the reinforcement effect was analyzed.The results show that the deflection value and stress of test beams are in the elastic range,and security reserves can be improved obviously,reinforcement effect is excellent;two kinds of reinforcement schemes-planting bar in webs and concrete-filled in hollow core slabs-have their respective characteristics,the comprehensive factors of actual situation should be considered when the method is chosen. |
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