Requirement of expansion joint for temperature load for RCC structures

Abstract

Concrete is the most commonly used material in building construction. Concrete structures are subjected to seasonal and daily temperature changes due to their interaction with the surrounding environment, in addition to live and dead loads. Significant change of temperature can impose large amount of stress in a structure. These thermal stress values can even exceed the stress values induced by the live and dead loading in case of no or little thermal insulation and could lead to severe damages if not considered during the design. One way of minimizing the temperature stress is to limit lengths of building. In Bangladesh National Building Code and many other national codes, there is no specific guideline for length limits or provision for considering stresses due to temperature load. This paper is aimed to determine the maximum permissible length of a structure without providing an expansion joint so that temperature changes do not create undue stresses. Parametric study involving thermal effect on RCC structures was performed for varying dimensions, conditions and story levels. If temperature effect for structures with significant length is considered, it has been found that top deflection and rebar percentage exceeds limiting values. The finding could become useful in guiding to set the permissible building length without expansion gap.