Research On Load Effect Coefficient During Concrete Casting Concerning Human Error

In recent years, formwork supports collapse frequently. As a result, people pay more attention to the load effect coefficient which is one of the most important factor on security problem of formwork-supporting system. As the survey says, structural human error on superstructure of formwork-supporting result in the consequence of load effect coefficient change from constant into random variable. However, academia is short of research on statistical property of parameters like this. The major contents of this work can be summarized as follows:(1) According to the research on 4 representative construction sites, the sample and the incidence of structural human error in formwork system are given.(2) To simulate occurrence rules of human error, nonlinear random finite element model is built by ANSYS finite element analysis software, which providing modeling approaches of soffit formworkâ†'joistâ†'stringerâ†'shore system considering human error. Accuracy of the finite element model is verified by comparing gap-size and its incidence rate to actual experiments.(3) According to numerical simulation of 11 construction conditions considering 500 human error situations of each state, to explore the reaction of 3 variables including construction load, formwork size and shore spacing on statistical property of load effect coefficient.The conclusions are as follows:(1) The incidence of structural human error and statistical property of gap size among joist, stringer and U-Head Jacks are given.(2) The load effect coefficient of shore and stringer satisfy with normal distribution and Weibull distribution, the construction load size plays small effects on the mean of load effect coefficient while standard deviation decrease gradually with the increase of construction load, both mean and standard deviation of load effect coefficient increasing with formwork size increasing, shore spacing has influence on both mean and standard deviation of load effect coefficient as well, but to a lesser extent.(3) The suggested value for load-effect coefficient is provided according to the force acting on shores and stringers.