EFFECTS OF CREEP AND SHRINKAGE ON THE DEFLECTION OF RCC TWO WAY FLAT PLATES

BS 8110-1997, ACI 318-2000 and IS 456-2000 Codes provide methods for calculating the short-term deflection, deflection due to Creep effects and Shrinkage effects for beams and oneway slabs. Though the codes are giving the provision for two-way slabs, as span to depth ratio for deflection control, much variation exists among them. Deflection calculation with creep and shrinkage effects is not included for two way slabs. Hence an attempt is made in this paper, to determine the total deflection including creep and shrinkage effects by suitably modifying the available formula for beams as per Equivalent frame method. A programme is developed in MATLAB to determine the exact deflection for two-way beamless slabs including short-term effects, Creep effects and Shrinkage effects. A numerical example is solved for flat plates by varying the parameters such as total thickness, characteristic compressive strength of concrete, clear cover of reinforcement, creep coefficient and the disparities among BS 8110-1997, ACI 318-2000, and IS 456-2000 are highlighted.