Numerical modeling of slipforming operations

Slipforming is a construction method in which the forms move continuously during concrete placement. This paper presents a numerical procedure based on the finite element method to simulate the thermal behavior of concrete during slipforming operations. The validity of the model was successfully tested by simulating a very complex but well documented field case of actual slipforming operations performed during the construction of an offshore concrete oil platform structure. The results obtained have been related to the shape of the concrete ?hardened front? in the forms, which allows quick evaluation of the operation. The results of the numerical investigation have shown that the shape of the hardened front? can be affected by the temperature of the fresh concrete and ambient conditions. For a given initial concrete temperature, there are limitations for the ambient temperature that, when exceeded, can create an unfavorable shape of the concrete ?hardened front? in the forms. Similarly, for a given ambient temperature,the initial concrete temperature should not be fall below an established limit in order to avoid unfavorable shape of the ?hardened front?.