Evaluation of early-age performance of reinforced concrete pile cap
The acceleration of construction in terms of early formwork removal or premature loading has a critical effect on the total construction cost. In order to perform the acceleration correctly, good decisions must be made. This paper provides a simple structural analysis method based on the strut-and-tie modelling which helps to make such decisions. The strength and stiffness development of concrete at early age is reviewed in the most relevant construction codes and the most suitable formulations are recommended. Then, the strength and stiffness development functions are introduced into the strut-and-tie model and the two-dimensional or three-dimensional structural analysis can be performed. The effect of creep is also included in terms of the creep coefficient so that the long-term consequences of the accelerated construction can be also evaluated. The proposed method is demonstrated in an example of a reinforced concrete pile cap. The method is useful either for engineering practice or for a quick rough verification of complex numerical simulations of hardening concrete when prematurely loaded.