Prediction and Control of Early-Age Cracking: Experiences From the Oresund Tunnel

The Oresund Link, a 16-km-long tunnel and bridge connecting Denmark and Sweden, opened on July 1, 2000. A 100-year service life was specified and the tunnel portion was designed to be watertight without external lining or insulation. The contract required that no early-age cracks be permitted in water-retaining portions of the structure and requirements for temperature differences and probability of cracking were strict. Due to novel casting methods used in the concrete tunnel segment, no early-age cracking occurred; however, cracking occurred in the ramp and portal structures which were cast in place. Overall, a fairly good correlation was found between pre-stressed and achieved temperature difference, probability of cracking, and actual cracking. This article describes the influence of temperature curing on early-age cracking, and discusses construction and design aspects of and experience with early-age crack control from the Oresund Link Tunnel.