Analysis Of The Randomness Of Creep And The Reliability Of Prestressed Concrete Beams

Creep has important implications for engineering structures especially the reliability of prestressed concrete structures.This paper uses Matlab and ANSYS finite element analysis software, to analysis the reliability of prestressed reinforced concrete beam with constant time-varying reliability analysis and considering the effect of creep. Based on the analysis of considering the time-varying reliability of creep effect, Through the comparison and analysis of the methods of calculating the aseismic reliability, it adopts the most appropriate analysis method to research the aseismic reliability and conducts the optimized analysis on the basis of the reliability. The main research content includes:In this paper, we combined with the project of a prestressed concrete beam, respectively to calculate the structure of the load effect combination and the effect combination of resistance. Set up functions and determine the random variables. Based on the Matlab software,using first-order reliability method, direct sampling method by monte carlo and sampling method by monte carlo to analysis the reliability of structures. And Comparative analysis of various methods is accurate. In addition to the various random variables to analyze the sensitivity of functions, determine the high sensitivity of random variables, the need to consider the factors in the practical engineering.Using the secondary development tools of Ansys(UPFs) and Combining with the FORTRAN programming language, on the basis of the specification and provide the expressions of concrete creep characteristics. Selecting the creep model is suitable for the actual situation, and altering the USERCR.F provided by Ansys, and analysising the creep effect of prestressed concrete beam in ANSYS.This paper researches and analyzes the rationales of PDS of ANSYS and writes the aseismic reliability analysis program of the prestressed concrete beam and the optimizer based on reliability by adopting the ANSYS Parameter Language and the Latin hypercube sampling method of Monte Carlo. Using the time discrete method, separating 10 part of times. Calculate the structural reliability of each time period and each random variable’s sensitivity respectively. Find wether satisfy certain regularity. In addition, analyze the influence of function by each random variable. Discussing all the random variables in different period, whether the reliability of the structure of the effects are the same. Sums up the influence on the structure reliability of random variables, put forward the corresponding suggestion in the process of the actual construction and as a major means of construction quality control method.