Joint cracks are a type of characteristic crack that occurs in the side walls of cast-in-place reinforced concrete open channels. In this study, thermal stress analysis was performed to analyze the cause and timing of joint cracks in the side walls of such channels. The distribution of maximum principal stress indicated that previously placed spans restrain subsequently placed spans, increasing the risk of generating joint cracks. This suggests that the waterstops buried in the previously placed spans restrain the deformation of the subsequently placed spans due to the difference in strength caused by the material ages. In addition, the risk of generating joint cracks increased with the increase in the casting intervals. The maximum principal stresses exceeded the tensile strength of the concrete around the joint sections for both summer and winter construction. Thus, joint cracks may occur at both early and long-term material ages, regardless of construction season. To obtain a more realistic thermal stress analysis, outside temperature models capturing the features of temperature data in Japan were proposed, and these models gave appropriate analysis results.

接缝裂缝是现浇钢筋混凝土明渠侧壁发生的一种特征性裂缝。在这项研究中，进行了热应力分析，以分析此类通道侧壁接缝裂纹的原因和时间。最大主应力分布表明，先前放置的跨度限制了随后放置的跨度，增加了产生接缝裂缝的风险。这表明，由于材料老化引起的强度差异，埋在先前放置的跨度中的止水带抑制了随后放置的跨度的变形。此外，随着浇注间隔的增加，产生接缝裂纹的风险也增加。无论是夏季还是冬季施工，最大主应力都超过了接缝部分周围混凝土的抗拉强度。因此，无论施工季节如何，接缝裂缝都可能在早期和长期材料使用年限内发生。为了获得更真实的热应力分析，提出了捕捉日本温度数据特征的室外温度模型，这些模型给出了适当的分析结果。