DEFLECTION CHARACTERISTICS OF RC BEAMS DUE TO CREEP

Abstract

This dissertation addresses the effects of creep on the serviceability of concrete structures i.e. mainly long-term deflection. It outlines why creep is important, its major influence on the magnitude of deflection in structures, and what to do about it in design. The deflection of beam is mainly depend on bending moment and stiffness of beam, but creep is a such property of concrete which increases the deflection as time passes under sustained load, irrelevant to stiffness and bending moment of beam. So study of characteristics properties of creep on RC beam has become important. Analytical procedures are described in codes for estimating long-term deflection of statically determinate beams due to effects of creep and shrinkage of concrete. The dissertation contains a detailed view of the considerations currently being made by the different countries codal provisions, i.e. IS 456:2000, ACI 318:2005, BS 8110: 1985 Part II, and Eurocode 2. By taking real loads from slab panels of building i.e. different loading condition and support condition, long-term deflection of RC beam has been calculated by different countries codal recommendation, and comparison has been made so as to know what is the difference in deflection, why this difference comes, and what parameters are responsible for this. Comparison has been made between the different experimental values calculated in the investigation by different researcher and deflection predicted by different countries codal provision for the same problem. The purpose of the comparison is to know what difference is in measured and predicted deflection and which code gives very good correlation with experimental results. So this study will be helpful to give some good suggestion regarding the revision of the long-term deflection provisions of IS 456:2000, particularly those clauses related to creep and shrinkage of concrete.