The Research On Design Method Of Durability Of Paste CFRP Reinforced Concrete Bridge In A Hot And Humid Environment

At present,reinforcement project whose small and medium span concrete beam bridge mostly use the method which is paste the CFRP reinforcement method at home and abroad.The extensive use of this method in engineering also creates a wide range of durability problems.Therefore,people want to further improve the durability of the reinforcement structure by studying the factors influencing the durability and the various environmental mechanisms,And to provide a theoretical basis for ensuring the durability of the reinforcement design.The existing design of the durability of concrete structures is based on the "Code for durability design of concrete structures ",And there is no suitable reference for the durability design of the adhesive reinforcement structure,What different from the design of a single concrete structure durability is that the paste reinforcement need to consider the durability whose the paste material 、 the adhesive layer and the component after the paste.Now there is a lot of results on the durability test of the CFRP reinforced concrete structure.However,there has not been a systematic design method for the durability of CFRP reinforcement for concrete beam bridge in hot and humid environment.In this paper,through the research and development of the key technology research on the durability of the reinforced concrete bridge under the coupling of the load and the hot and humid environment,the paper analyzes the results obtained in the relevant experimental study,and combines with the existing research on the hot and humid environment The paper puts forward the design method of the durability of CFRP reinforced concrete beam bridge under hot and humid environment.The main contents are as follows:Firstly,based on the analysis of the temperature and humidity influence coefficient A in the τ-s constitutive relation of the interface bond slip,the classification of the hot and humid environment is classified according to the range of A value,when A(30,40),the hot and humid environmental impact is relatively large,should be classified as Ⅰ;when A(40,50),the hot and humid environment is relatively moderate,should be classified as Ⅱ;when A(50,60),the impact of hot and humid environment is relatively small,should be classified as Ⅲ.Secondly,by taking into account the impact of the role of hot and humidenvironment,the quality of reinforced structural materials to the requirements,including the requirements of the CFRP,the requirements of the structural adhesive,the requirements of the protective material.Thirdly,the factors influencing the attenuation of the reinforcement structure are analyzed,including the attenuation of the concrete strength,the attenuation of the strength of the steel bar,the decay of the reinforcement caused by the corrosion of the steel,the attenuation of the CFRP-concrete interface caused by the hot and humid environment,and the reinforcement of the normal cross section The calculation formula of the bearing capacity of the CFRP reinforcement is calculated and the calculation of the reliability index β of the reinforcement structure is carried out.Fourthly,considering the influence of hot and humid environment,the design requirements of detail based on durability are put forward,including the protection requirements of U-shaped hoop and other protective structures,the anchoring requirements of CFRP,the additional structural requirements to ensure the structural safety,the protection requirements of the original structure after reinforcement,Drainage measures.Finnally,according to the design method of the durability of CFRP reinforcement and its detailed structural design,the three stages of construction preparation,construction process,inspection and acceptance are put forward to help improve the durability of reinforcement.