Reliability Study On FRP Flexural Strengthening Of Reinforced Concrete Beam

Fiber Reinforced Plastics(FRP)is a kind of new material with high use value,a wide variety,price economy,compared with other materials,it has good tensile properties,light quality,corrosion resistance,the use of convenient and other notable advantages,so in civil engineering has been widely used,because China's construction industry is facing a large number of buildings need to repair and strengthen the problem,the use of FRP to strengthen the building technology is becoming more sophisticated and mature,for the use of FRP reinforcement bending damage and endurance analysis,Scholars at home and abroad have carried out relevant research,and put forward many models with practical application value,the State also attaches great importance to this,promulgated the relevant design norms.In this paper,four kinds of typical failure modes of FRP flexural reinforced concrete beams are analyzed,and the correlative reliability analysis is carried out through Monte Carlo simulation method,besides,the differences of design norms between China and America are compared,the work of this paper and the main innovations are as follows:(1)The relevant data of FRP flexural reinforcement reinforced concrete beams are collected from domestic and foreign literatures,and based on this,a huge database is built,and on this basis,SPSS are used to analyze the variance of each factor,and finally,the basic variables are obtained to share the FRP ratio.Finally,it concludes that: the axial compressive strength of concrete,the longitudinal reinforcement ratio of steel bar,and the ratio of FRP cross section distribution have significant influence on FRP contribution.(2)Collecting and collating the statistical characteristics of the random variables involved in the calculation of the reliability of FRP flexural reinforcement beams.In addition,considering the strength of the concrete and FRP two kinds of materials is sensitive to the bearing capacity,the cubic compressive pressure of 600 concrete specimens and the uniaxial tensile test of 50 FRP specimens are carried out to obtain the statistic characteristics of the mechanical properties of the two materials.Based on the results of the analysis and the existing literatures,the ratio of the mean and nominal value of the axial compressive strength of concrete is 1.25,and the elastic modulus of the 0.15 limit tensile strength of 1.15 and 0.1 respectively is taken 1.0 and 0.04 respectively.(3)To establish the state equation of ultimate bearing capacity by using the model of China-US standard,and then calculate the difference of reliability between Chinese and American design codes,and the influence of variables on reliability.(4)According to Monte Carlo-Jc method and Monte Carlo method,the calculation program based on Matalb is compiled respectively,and the time-varying reliability of concrete beam before and after the reinforcement of the marine environment is calculated.At the same time,by comparing two reliability calculation methods,it isproved that Monte Carlo-Jc method is an efficient reliability calculation.