Experimental Study On Safety Assessment Of Reinforced Concrete T Beam Bridge Before And After Reinforcement

With the rapid development of bridge construction in our country,there are many problems of bridges that are caused by insufficient bearing capacity in recent years,the key problems is not able to accurately assess the bearing capacity of the bridge construction.The maintenance,reinforcement,or reconstruction of the existing reinforced concrete bridges are based on the accurate evaluation of the carrying capacity of the bridge structures.Avoiding the excessive evaluation of the bearing capacity of reinforced concrete bridge structure leads to potential safety hazard,and also needing to avoid under assessment leads to premature reinforcement or unnecessary economic losses.Therefore,it is very important to make a reasonable assessment of the bearing capacity of the concrete structure of bridges which are still in operation.This paper belongs to the sub-project of recycling experimental research of small span girder bridge used for many years for the science and technology project of Yunnan Province.The 4 piece of reinforced concrete T beams taking from the upper part of the reinforced bridge are used to conduct a comparative trial study.Among them,the first piece of reinforced concrete T beam(T1)is from the T beam of removing the reinforced steel plate and reinforced concrete layer,the second piece of reinforced concrete T beam(T2)is from the T beam of only removing the reinforced concrete layer,the third piece of reinforced concrete T beam(T3)is from the T beam of only removing the reinforced steel plate,and the fourth piece of reinforced concrete T beam(T4)is from the T beam of the reinforced steel plate and reinforced concrete layer.The main accomplishments and results are as follows:(1)The disease and reinforcement method of reinforced concrete beam are introduced in detail.This paper discussed the causes and detection methods of the diseases of T beams.The applicability of T beam strengthening method,the stress characteristics and analysis methods of reinforced structures are discussed.(2)Four piece of reinforced concrete T beams are specially inspected,the test includes test of concrete strength,concrete carbonation depth detection,the protective layer thickness detection,reinforcement corrosion detection and chloride ion content detection.On this basis,the ultimate bearing capacity of four piece of reinforced concrete T beams are calculated by the specifications and finite element simulation analysis,and their comparison study is carried out.(3)The project of Loading of four piece of test beams are designed and are carried out experiments.the stress,the deformation response,the ultimate bearing capacity and failure modes of T1,T2,T3 and T4 are abtained;Then through the contrast research of four piece of test beams,the ultimate bearing capacity of T beam ofthe steel plate reinforcement,top concrete layer reinforcement and the combined reinforcementare improved.The results are compared with those of the standard and finite element simulation.(4)A evaluative method of the safety of reinforced concrete T beams under load is proposed.The method is based on the ratio of deflection to span.This method can be applied to the static load test of beam bridges.