Influence factors of thermal stress in the construction period of the concrete outer tank for 160 000 m3 LNG storage

Abstract:

To investigate the cracking resistance and avoid the vertical and local circumferential cracks at the bottom of the concrete outer tank during the construction period due to hydration heat, concrete shrinkage and temperature changes for 160 000 m³ liquefied natural gas (LNG) tanks, using the finite element numerical simulation technology, the influence of shuttering material, construction quality, construction season and pouring temperature on cracks was figured out with an incremental method. The results show that concrete shrinkage leads to a sustaind growth of concrete tensile stress, the thermal stress fluctuates according to the changing of construction temperature and construction quality and construction season have a strong inference on cracks. Based on this basis, the thermal tress is dismantled according to the effect of each influencing factor, and the whole thermal stress is the superposition of the thermal stress under single influence of hydration heat, concrete shrinkage, construction season and pouring temperature. Some suggestions on anti-cracking measures are proposed, mainly by regulating the construction season, complementally by improving the quality of construction.