Time Dependent Strength and Stiffness of Shear Controlled Reinforced Concrete Beams under High Sustained Stresses
Time Dependent Strength and Stiffness of Shear Controlled Reinforced Concrete Beams under High Sustained Stresses
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高持续应力下受剪控制钢筋混凝土梁的随时间变化的强度和刚度
DOI：
10.1061/9780784482896.005
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Tian, Ying
中科院分区：
文献类型：
--
作者：
Clark, Russell;Shubaili, Mohammed;Elawadi, Ali;Orton, Sarah;Tian, Ying
设计和施工错误以及材料劣化可能导致混凝土构件承受高水平的持续应力，远远超过典型的使用水平。这些高水平的持续压力导致了美国和世界各地的结构性崩溃。然而，受剪切控制的混凝土构件（梁和板柱连接）在高持续应力下的性能尚不清楚。在高持续压应力（大于0.75 fc’）下，混凝土将遭受以加速永久应变为特征的三级徐变，最终导致破坏。钢筋与混凝土的粘结也受到影响，导致滑动。本研究提出了剪切控制RC梁的实验测试结果，加载到其短期容量的81%，86%和92%，并观察了大约四周。在整个持续载荷试验过程中，记录每个试样的挠度和应变测量。在高持续应力下，试件随着时间的推移显示出持续的挠曲，大部分挠曲发生在施加荷载后不久。破坏后的试件表现出比对照试件更大的弯曲响应。测试结果表明，高水平的持续压力（高达其短期能力的92%）可以持续很长时间；然而，挠度和开裂增加，最终破坏模式可能发生改变。这些信息将帮助工程师识别在高水平持续压力下接近失效的元件。
Design and construction errors and material deterioration can lead to concrete elements being subjected to high levels of sustained stress well exceeding typical service levels. These high levels of sustained stress have led to structural collapses in the United States and around the world. However, the performance of shear-controlled concrete elements (beams and slab-column connections) under high sustained stress is not well understood. Under high sustained compressive stress (greater than 0.75 fc’) concrete will suffer tertiary creep characterized by accelerated permanent strain, leading eventually to a failure. The bond of the reinforcing bars to the concrete is also affected leading to slip. This research presents the results of experimental tests on shear-controlled RC beams that were loaded to 81, 86, and 92 percent of their short-term capacity and observed for about four weeks. Deflection and strain measurements were recorded for each specimen throughout the sustained load test. Under high sustained stress the specimens showed continued deflection with time, with most of the deflection occurring shortly after the application of load. The failure of the specimens exhibited more flexural response than that of the control specimen. The test results show that high levels of sustained stress (up to 92% of their short-term capacity) can be sustained for a prolonged time; however, the deflections and cracking are increased and the ultimate failure mode may be changed. This information will help engineers identify elements nearing failure under high levels of sustained stress.
持续荷载下混凝土梁的抗剪承载力
DOI：
--
发表时间：
2013
期刊：
影响因子：
--
作者：
R. Sarkhosh;J. Walraven;J. Uijl;C. Braam
通讯作者：
C. Braam
持续过载对钢筋混凝土梁强度和塑性流动的影响
DOI：
--
发表时间：
1953
期刊：
影响因子：
--
作者：
G. W. Washa;P. G. Fluck
通讯作者：
P. G. Fluck