Reliability Analysis On Deflection Control Of Concrete Crane Beam

Compared with concrete flexural members in civil buildings,concrete crane beams in industrial buildings have more severe service environments and higher reliability requirements on deflection control.However,the research on the reliability of concrete crane beams in and abroad is still immature,especially on the serviceability.Following are some of the main reasons: First,the probability characteristics of random variation are not well established for vertical loads of cranes,thus hard to consider the influence on the reliability analysis of the deflection control of concrete crane beams;Second,the frequent or quasi-permanent values of vertical loads for load combination should be the order values,not the maximum values,furthermore,the way of combination should be the random processes,not the random variables.The main contents of this paper are as follows: First,the statistical parameters(e.g.mean coefficient,variation coefficient,et.al.)are calculated through the probabilistic model of the combined effect of vertical loads of cranes;Second,random variable and random process combination methods are compared in both in theory research and practical application;Third,the random process combination method is used to analyze the deflection control of both reinforced concrete crane beam and pre-stressed concrete crane beam considering the probability model of crane vertical load,then the results are compared with those of ordinary concrete flexural members;Last,the controlling of variables is used to analyze the affecting of each factors on reliability,so as to determine the master variable.This paper builds a probability model of crane vertical load,establishes arelatively complete reliability analysis model of deflection control by means of the random process combination method.and analyzes the reliability of reinforced concrete crane beams,pre-stressed concrete crane beams allowed or not allowed cracks.This method will provide a reference to design and evaluation of crane beams.