Effect of pipe-cooling system on thermal-mechanical behaviour of PC box bridge girders at hydration age
Effect of pipe-cooling system on thermal-mechanical behaviour of PC box bridge girders at hydration age
复制标题
管道冷却系统对水合龄期PC箱梁热力性能的影响
DOI：
10.1186/s43251-020-00009-4
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发表时间：
2020-09
期刊：
影响因子：
--
通讯作者：
Zhang Yongfei
中科院分区：
文献类型：
--
作者：
Song Chaojie;Zhang Gang;Wen Hao;Zhang Yongfei
墩顶预应力混凝土箱梁在水化龄期由于内外温差大，容易产生温度裂缝。本文提出了一种研究预应力混凝土箱梁早期养护性能的方法。首先，基于一典型PC箱梁的实测数据，提出了基于遗传算法和热学分析的混凝土水化热绝热温升函数反分析方法。在此基础上，利用ANSYS软件建立了考虑时变风速和环境温度的热-水-力耦合模型，分析了考虑管道冷却系统的PC箱梁的热力性能。随后，进行了参数研究，以评估冷却时间，冷却水流量，冷却水温度和冷却时间对PC箱梁在固化过程中的温度和应力的影响。分析结果表明，在冷却过程中，钢管附近产生的主拉应力增加较快，而在冷却结束时，钢管附近的温度和主拉应力均显著降低。增加冷却时间、冷却水流量或降低冷却水温度均可降低最高温度。但是，这些冷却参数的取值不合理，会导致钢管周围主拉应力过大而导致PC箱梁开裂。一级冷却和两级冷却都是减少PC箱梁水化热不利影响的有效措施。
Prestressed concrete (PC) box bridge girders on the pier top is prone to generate thermal cracks due to large inner-outer temperature difference at hydration age. This paper presents an approach for investigating behaviour of PC box bridge girders at early age of curing. First, based on measured data from a typical PC box bridge girder, an inverse analysis method for adiabatic temperature rise function of concrete hydration heat is proposed using genetic algorithm and thermal analysis. Then, a thermo-hydro-mechanical coupling model is established, using the computer program ANSYS incorporating time-dependent wind speed and ambient temperature, to analyse thermal mechanical behaviour of PC box bridge girders considering pipe-cooling system. Subsequently, parametric studies are carried out to evaluate influence of cooling time, cooling water flow rate, cooling water temperature and cooling period on temperature and stress of PC box bridge girders during curing. Results from analysis show that the principal tensile stress generated in the vicinity of pipe increases more rapidly during cooling, while the temperature and principal tensile stress can be significantly reduced when cooling is terminated. Increasing cooling time, cooling water flow rate or decreasing cooling water temperature can reduce the highest temperature. However, unreasonable value of these cooling parameters will cause PC box bridge girders cracking due to excessive principal tensile stress around pipe. Both one-stage and two-stage cooling are effective measures to minimize the adverse effects of hydration heat in PC box bridge girders.
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影响因子：
5.3
作者：
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影响因子：
7.4
作者：
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影响因子：
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DOI：
10.1108/09615531111123100
发表时间：
2011-01-01
影响因子：
4.2
作者：
Chen, Sheng-hong;Su, Peifang;Shahrour, Isam
通讯作者：
Shahrour, Isam