CONTROL OF CRACKING IN WALLS RESTRAINED ALONG THEIR BASE AGAINST EARLY THERMAL MOVEMENTS

摘要

A significant problem in the design of retaining walls, abutment walls etc. is the treatment of cracking due to restraint of early thermal contraction. Formulae are given in BS8007 for the treatment of this problem but these differ greatly from those proposed elsewhere. The basic structural model from which both the UK and European approaches are derived is that of a member restrained at its ends against overall shortening. The reality of many walls is that they are restrained not at their ends but along the base by a pre-existing foundation. It is shown that the factors influencing cracking in the case of base restraint are quite different to those, which control cracking due to end restraint. A study is being carried out at the University of Leeds into the behaviour of base restrained walls. Initial theoretical work and the use of Finite Element simulation has produced the basis for an alternative approach to crack control. These studies will be described in the paper. Experimental validation of the theoretical study and the formulae is planned but has yet to be started.