STUDY ON LOSS OF CONTACT OF RECTANGULAR PLATES RESTING ON COHESIVE SOIL

Objectives: To study the phenomenon of loss of contact of rectangular plates resting over cohesive soils. Study the effect of various L/B ratios on Critical Relative Rigidity (CRR), the effect of eccentricity of loading on CRR and effect of poisons ratio on CRR over the phenomenon of loss of contact. Methodology: Analysis is carried out for a Rectangular Footing resting on cohesive soils subjected to an eccentric concentrated load, with eccentricity in the middle one-third of its shorter and longer span dimension with varying poisons ratio from 0.1 to 0.5 with an interval of 0.05 and the loss of contact of footing with the underlying soil phenomena is analyzed using the ANSYS 12.0 and the CRR values are obtained for different L/B ratios up to two distribution The term Relative Rigidity (RR) which takes into account the properties of soil and footing is considered for the analysis. It considers the parameters like dimensions of footing, thickness and the young's modulus of the footing and the modulus of subgrade reaction of the soil. The Critical Relative Rigidity (CRR) is the value of RR where the soil experiences loss of contact with the overlying footing and the Critical Relative Rigidity (CRR) values are obtained for various L/B ratios up to the two-way distribution. Findings: With the increase in the eccentricity of concentrated load the CRR value decreased and with the increase of L/B ratio the CRR value increased and for an increase in poisons ratio for all L/B ratios and eccentricities CRR value decreased. Applications: Useful in the design of footings in different soil bed conditions by altering the dimensions and making the design economical.