PROPOGATION OF CRACKS IN FIXED-FIXED REINFORCED CONCRETE BEAMS

Many normally reinforced concrete structures stiffer from cracking due to changes in environmental conditions as well as to alternations in loading conditions acting either separately or in a combination. Cracking of a concrete element will reduce its stiffness to some extent that means changing the deformation of the whole member as well as the distribution of bending moments along statically indeterminate structures. Redistribution of bending moments along an indeterminate member will depend mainly on its boundary conditions and type of loading subjected to which define the regions and extent where cracks do propagate. In this paper the propagation of cracks in fixed-fixed beam, loaded once with a concentrated point load at mid span and the other case with a uniformly distributed load on the whole span, has been studied and presented. Results for the effect of these cracks on deflection and bending moment redistribution are given for a number of ratios relating the moment of inertia of cracked section to the moment of inertia of uncracked section, and proper factors taking this effect into consideration when designing of such beams have been suggested.

• INTRODUCTION

• CRACKING PHENOMENON IN NORMAL RC STRUCTURES

• CRACK PROPAGATION IN RC FIXED-FIXED BEAMS

• MOMENT REDISTRIBUTION DUE TO CRACKING

• CRACKING EFFECT ON DEFLECTION

• DISCUSSION OF RESULTS

• CONCLUSIONS AND RECOMMENDATIONS

• REFERENCES