Kunming, Yunnan, China
476 feet high / 145 meters high
525 foot span / 160 meter span
The highest bridge along the expressway that radiates out from northwest Kunming city to Wuding, the Xiyoudong prestressed beam bridge is locked between two mountain tunnels with a span configuration of 88+ 160+ 88 meters. The piers vary between 70 and 84 meters high.
During construction, the remote and inaccessible pier foundations made construction difficult. The bases measure 13.2m × 13.2m × 5m with a concrete square volume of 871.2 cubic meters. Construction of the foundation gathers hydration heat in the concrete inside and outside with the heat cooling unevenly and subject to internal and external constraints that lead to greater temperature stress and cracks.
Therefore, they adopted internal cooling pipes buried within the 5-meter-high pile caps with a 24-hour water cycle, gradually reducing the pile cap temperature. The project technicians had a pile cap field measurement with a maximum temperature of 65 degrees. This water cycle was extended by 7 days to 14 days to ensure the foundations were all solid.