ANALYSIS OF REINFORCED CONCRETE BUILDING DURING CONSTRUCTION (COMPUTER MODEL, CREEP, RANDOM, NONLINEAR)
Abstract
High-rise reinforced concrete buildings are usually constructed by supporting each newly cast slab on a number of previously cast floors. The supporting assembly consists of several slabs of various ages, formwork, shores, and reshores. Recent surveys indicate that a significant percentage of the concrete construction disasters in multistory buildings is traceable to excessive loads applied to the supporting assembly. The problem is particularly troublesome in multistory reinforced concrete buildings, in which the live load is small compared with the dead load. To date, only a few studies have been conducted on the development of analytical model to simulate the construction process. Moreover, none of these models has been chosen or confirmed by the code or standard writing bodies. The research develops new computer-based analytical models which can be used to simulate the construction process more realistically because the great variety of construction conditions are considered. Based on the new models, many factors which influence the load distribution in the slab-shore system have been examined. It is found that the shore axial stiffness is an important parameter. Random variation of the modulus of elasticity of wooden shores (E(,w)) causes the mean value of the maximum shore load to increases by 9%. In order to introduce limit state principles into the design of formwork, a random analysis of the maximum load for a customary construction procedure has been carried out. It is found for wooden shore systems that the influence of the random variation of E(,w) on the maximum shore load must be considered. For the maximum shore load, the live load is more significant. When the shore system is not very soft, it is recommended that the maximum slab moments and shore loads predicted by Grundy and Kabaila, under normal construction conditions, can be corrected by using a modification coefficient which may vary from 1.05 to 1.10.
Degree
Ph.D.
Subject Area
Civil engineering
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