Zhang Tan, Wang Hua, Luo Yuejing, Yuan Ye, Wang Wensheng
Yulin Highway Development Center of Guangxi Zhuang Autonomous Region, Yulin 537000, China.
Bridge Engineering Research Institute, Guangxi Transportation Science and Technology Group Co., Ltd., Nanning 530007, China.
Materials (Basel). 2023 Apr 6;16(7):2925. doi: 10.3390/ma16072925.
The steel box arch bridge in this study will be subjected to various temperature effects from the construction to the operation stage, including the cement hydration heat effect and the sunshine temperature effect caused by an ambient temperature change. Therefore, it is very important to control the temperature effect of steel box arch bridges. In this study, the newly built Dafeng River Bridge is selected as the steel box arch bridge. This study aims to investigate the temperature effect including hydration heat and the sunshine temperature effect of the construction process of a rigid frame-tied steel box arch bridge. The manuscript presents that the heat dissipation performance of concrete decreases with the increase in the thickness of a mass concrete structure. The average maximum temperature values of layer No. 3 are about 1.3, 1.2, and 1.1 times the average maximum temperature value of layer No. 1 for the mass concrete of the cushion cap, main pier and arch abutment, respectively. The higher the molding temperature is, the higher the maximum temperature by the hydration heat effect is. With each 5 °C increase in the molding temperature, the maximum temperature at the core area increases by about 45 °C for the mass concrete. The pipe cooling method is conducive to the hydration heat control effect of mass concrete. Based on the monitored temperature change and displacement change, the influences of daily temperature change on the steel lattice beam and arch rib are analyzed. A temperature rise will cause the structure to have a certain camber in the longitudinal direction, and the longitudinal or transverse displacement caused by the sunshine temperature change is no less than the vertical displacement. Due to the symmetrical construction on both sides of the river, the arch rib deformation on both sides presents symmetrical synchronous changes. Based on 84 h of continuous temperature monitoring on-site, the changing trends of the arch back temperature and ambient temperature are consistent and their difference is small during 1:004:00 in the morning, which is determined as the appropriate closure time for the newly built Dafeng River Bridge.
本研究中的钢箱拱桥从施工到运营阶段会受到各种温度效应影响，包括水泥水化热效应以及环境温度变化引起的日照温度效应。因此，控制钢箱拱桥的温度效应非常重要。在本研究中，新建的大丰河桥被选为钢箱拱桥。本研究旨在探究刚架系杆钢箱拱桥施工过程中的温度效应，包括水化热和日照温度效应。该论文提出，大体积混凝土结构的散热性能随厚度增加而降低。对于承台、主墩和拱座的大体积混凝土，第3层的平均最高温度值分别约为第1层平均最高温度值的1.3倍、1.2倍和1.1倍。成型温度越高，水化热效应产生的最高温度越高。对于大体积混凝土，成型温度每升高5℃，核心区域的最高温度升高约45℃。管道冷却法有利于大体积混凝土的水化热控制效果。基于监测到的温度变化和位移变化，分析了日温度变化对钢格构梁和拱肋的影响。温度升高会使结构在纵向产生一定的拱度，日照温度变化引起的纵向或横向位移不小于竖向位移。由于在河两岸对称施工，两侧拱肋变形呈现对称同步变化。基于现场84小时的连续温度监测，凌晨1:004:00期间拱背温度与环境温度变化趋势一致且差值较小，确定此为新建大丰河桥的合适合龙时间。
