THE EXPERIMENTAL RESEARCH ON THE BENDING BEHAVIOR OF THE STRENGTHENED PRE-STRESSED CONCRETE HOLLOW SLABS

摘要

With the rapid development of road transportation and communication, in particular due to the universality of the vehicular load aggrandizement and surcharge, the aging, impairment and carrying capacity depress occur on quite a number of service bridges, which bring severe potential problems to the safety of the bridge structure. Four pre-stressed concrete hollow slabs aged about ten years are adopted to be the test object. Firstly, through destructive load tests of two slabs, ultimate bearing capacity and failure mechanism are analyzed. Then the strengthening methods of increasing the section area and bonding CFRP on compress and tensile region are applied on another two slabs separately. By destructive load test after strengthening, the strengthen influence on the ultimate bearing resistance and failure mechanism of different strengthening measures are investigated. The test shows that applying CFRP on tensile region of the slab gains satisfying effects. And the ultimate bearing resistance increases 20%. With the method that increasing the section area on compress region, the old concrete can be well combined with the new pavement concrete via rebar planting, which brings better effects and the ultimate bearing resistance surpasses 60%. Based on the test result, reasonable programs and related suggestions of strengthening old bridge concrete hollow slabs are brought up.