합성단면의 콘크리트 크리프 해석을 위한 이완계수법

The concrete creep deformation of a hybrid composite section can cause additional deformation of the composite section and the stress relaxation of pre-compressive stress on the concrete section due to partial restraint of the deformation. In this study, the stress relaxation coefficient method (SRCM) was derived for simple analysis of complicate hybrid or composite sections with engineering purpose, and an equation of the stress relaxation coefficient (SRC) required for the SRCM was proposed. The SRCM was derived with the parameters of a creep coefficient, section and loading properties as same method as the constant-creep step-by-step method (CC-SSM). The errors of the SRCM was improved by using the proposed SRC equation than the average SRC's which were estimated from the CC-SSM. The root mean square error(RMSE) of the SRCM with the proposed SRC equation was less than 1.2% to the creep deformation at the free condition and the 99% reliability was 3.3% for not greater than 3 of creep coefficients. The proposed SRC equation reflects the internal restraint of composite sections, and the effective modulus of elasticity computed with the proposed SRC can be used effectively for the rigidity of a composite section in a numerical analysis which is applied for analysis of the external restrain effects of boundary conditions.