ABSTRACT
Abstract The risk of thermal cracking depends apart from temperature itself on a number of parameters such as e.g. restraint conditions, mechanical behaviour in the young concrete, and temperature development. During the last decade studies of thermal behaviour in concrete have been carried out at Lulea University of Technology. In the massive pier shafts at the Igelsta Bridge, Sweden, several in-situ studies have been made for both noncooled and air-cooled sections. Early experiences from the building site as well as results from measurements and simulations had shown unacceptably high tension levels in the piers unless remediating measures were taken. A system of air-cooling vAth embedded pipes was chosen. The positive effects of this approach have been confirmed by further measurements. In order to design an air-cooling system the required cooling effect must be determined. The computed coolmg effects based on measured changes in air temperature along the cooling-pipes have been compared with the corresponding effects calculated from general heat transfer equations. The results imply that a feasible model of designing a cooling system was found. Keywords: Cooling Systems, Heat Transfer, Risk of Cracking, Structural Members (Concrete Pier Shafts).
