| Among the existing bridges in our country,there are a large number of old bridges that have been in service for over 20 years but are still within their lifespan,with ribbed girder bridges being the majority.Due to their early construction,the design level and load of these old ribbed girder bridges are not high.In addition,due to long-term operation,the bridge structure,especially the bridge deck,is severely damaged,the bearing capacity is significantly reduced,and they face problems such as insufficient safety,greatly affecting driving safety and unable to meet current traffic requirements.Strengthening the old ribbed girder bridge deck to enhance its load-bearing capacity is an urgent problem to be solved and an important research topic in bridge reinforcement and renovation.This thesis produced a total of 12 test plates,of which 3 reference control plates and 6 reinforced test plates were designed according to the "Standard Drawing of Highway Bridges and Culverts" published in 1983 to represent the old ribbed girder bridge deck.In addition,3 test plates were designed according to the "General Drawing of Highway Bridges" prepared by the Ministry of Transportation in 2008 as reference control plates,representing the new ribbed girder bridge deck.Select steel plate as the reinforcement material,and use bolts and adhesives to reinforce the old ribbed girder bridge deck with steel plate.Static load and impact damage tests were carried out on the 12 design test plates mentioned above.In the bending test,three different directions of reinforcement research were carried out,including different length of steel plates,different bolt spacing,and whether the bottom of the bridge deck has support.The reinforcement effect of the old ribbed girder bridge deck strengthened with steel plates was explored through failure mode,steel plate strain,stiffness and bearing capacity.In addition,finite element numerical simulation was conducted to verify the experimental results and expand the simulation for other working conditions.The test results and conclusions in this thesis include:(1)The ultimate load of the test plate strengthened with steel strips with a length of 1100 mm and a bolt spacing of240 mm increased by 20%,the ultimate load of the test plate strengthened with steel strips with a length of 1800 mm and a bolt spacing of 240 mm increased by 70%,and the ultimate load of the test plate strengthened with steel strips with a length of 1800 mm and a bolt spacing of 240 mm increased by 125%,which shows that the steel strips have a good effect on strengthening the old ribbed girder bridge deck,Among them,the test plate with support has the highest improvement in bearing capacity.(2)The impact test was carried out after the test plate was strengthened with steel plate strips.The test shows that the steel plate reinforcement has a certain inhibitory effect on the development of cracks.(3)Finite element numerical simulation found that using long steel plates for reinforcement,with a steel plate width of 160 mm,bolt spacing of200 mm,and variable diameter bolt arrangement,is the optimal reinforcement method in practice.(4)Based on the existing calculation formula,this thesis discusses the calculation method of the stiffness and bending capacity of the bridge deck with wet joints strengthened by steel strips,and adds the relevant parameters considering the wet joints of the bridge deck to calculate the bearing capacity of the bridge deck strengthened by steel strips.(5)This thesis makes a comparative analysis of the economic benefits of the steel plate reinforcement of the bridge deck,and concludes that the steel plate reinforcement has certain benefit advantages,which provides some feasible references for the actual engineering reinforcement. |
