Nassar Musab, Amleh Lamya
Civil Engineering Department, Toronto Metropolitan University, Toronto, ON M4B 2K3, Canada.
Sensors (Basel). 2023 Sep 30;23(19):8206. doi: 10.3390/s23198206.
This study examines the temperature distributions and thermal-induced responses in reinforced concrete bridge elements, focusing on the Canadian climate regions. The Canadian Highway Bridge Design Code (CHBDC) currently utilizes a fixed thermal gradient profile that does not account for regional climatic variations. Historical environmental data determines the effective maximum temperatures in the CHBDC. In order to investigate temperature behaviors and distributions, a transient finite element (FE) model is developed using recorded and calculated 3-month thermal loads data for representative cities in different climate regions. The results indicate that the predicted daily maximum effective mean temperatures and extreme daily positive vertical thermal gradients do not align. A linear correlation exists between the daily maximum effective mean temperature and the daily maximum air temperature, with a coefficient of determination (R) of 0.935. The proposed effective mean temperatures obtained from the FE thermal analysis are higher than the CHBDC recommendations. New thermal gradient profiles are proposed for Canadian climate zones, consisting of two straight lines and a linear gradient at the top and bottom sections. A comparison between the proposed profiles and the CHBDC and AASHTO specifications reveals that a single fixed thermal gradient profile is inadequate to account for the variation in thermal gradients across Canadian climate regions.
本研究考察了钢筋混凝土桥梁构件中的温度分布和热致响应，重点关注加拿大气候区域。加拿大公路桥梁设计规范（CHBDC）目前采用的是固定热梯度分布，未考虑区域气候差异。历史环境数据决定了CHBDC中的有效最高温度。为了研究温度行为和分布，利用不同气候区域代表性城市记录和计算的3个月热荷载数据建立了瞬态有限元（FE）模型。结果表明，预测的日最高有效平均温度和极端日正垂直热梯度不一致。日最高有效平均温度与日最高气温之间存在线性相关性，决定系数（R）为0.935。有限元热分析得到的建议有效平均温度高于CHBDC的建议值。针对加拿大气候区提出了新的热梯度分布，由两条直线以及顶部和底部的线性梯度组成。将建议的分布与CHBDC和AASHTO规范进行比较后发现，单一固定热梯度分布不足以解释加拿大气候区域内热梯度的变化。
