| 超高性能混凝土深梁受剪性能 |
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| 引用本文： | 周家亮,陈宝春,马熙伦,罗璐璐,黄卿维,苏家战.超高性能混凝土深梁受剪性能[J].交通运输工程学报,2020,20(6):117-125. |
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| 作者姓名： | 周家亮 陈宝春 马熙伦 罗璐璐 黄卿维 苏家战 |
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| 作者单位： | 1.福州大学 土木工程学院, 福建 福州 3501162.宁夏大学 土木与水利工程学院, 宁夏 银川 750021 |
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| 基金项目： | 国家自然科学基金;国家重点研发计划;福建省自然科学基金 |
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| 摘 要： | 为促进超高性能混凝土(UHPC)深梁的应用, 进行了4根以混凝土强度为主要参数的UHPC深梁受剪性能试验, 并开展了C40和C80混凝土深梁的对比试验; 分析了UHPC深梁的荷载-挠度曲线、破坏模式、钢筋应变、裂缝形态与极限荷载; 为探讨现有普通混凝土深梁受剪承载力计算方法是否可用于UHPC深梁, 应用《混凝土结构设计规范》(GB 50010—2010)对6根深梁试件进行了抗剪强度计算。研究结果表明: 混凝土强度越大, 在相同荷载下深梁的刚度越大, 在深梁开裂前的弹性阶段, UHPC试件刚度随钢纤维掺量的增大略有增大; 与C40和C80混凝土深梁一样, UHPC深梁裂缝包括弯剪裂缝和腹剪裂缝, 当荷载分别为13%~22%和18%~34%极限荷载时, 两类裂缝先后出现; UHPC深梁在加载全过程中梁、拱受力机制共存, 加载前期梁受力机制起主导作用, 后期则拱受力机制起主导作用; UHPC深梁裂缝多而密, 发生剪压破坏, 在支座上端反拱区不产生裂缝, 而C40和C80混凝土深梁出现斜压破坏, 且在支座上端反拱区产生裂缝; 试验梁受剪承载力随混凝土强度的增大约呈指数式增大, 混凝土强度从C40增大到C80、C190时, 其受剪承载力分别增大了30.76%和201.92%;采用《混凝土结构设计规范》(GB 50010—2010)中方法计算的UHPC深梁受剪承载力与试验值比值的均值为0.89, 均方差为0.15, 在没有更精确的计算方法之前, 该计算方法暂时可用。
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| 关 键 词： | 桥梁工程 超高性能混凝土 深梁 混凝土强度 受剪承载力 试验 |
| 收稿时间： | 2020-07-16 |
Shear performance of ultra-high performance concrete deep beams |
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| ZHOU Jia-liang,CHEN Bao-chun,MA Xi-lun,LUO Lu-lu,HUANG Qing-wei,SU Jia-zhan.Shear performance of ultra-high performance concrete deep beams[J].Journal of Traffic and Transportation Engineering,2020,20(6):117-125. |
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| Authors: | ZHOU Jia-liang CHEN Bao-chun MA Xi-lun LUO Lu-lu HUANG Qing-wei SU Jia-zhan |
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| Affiliation: | 1.College of Civil Engineering, Fuzhou University, Fuzhou 350116, Fujian, China2.School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, Ningxia, China |
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| Abstract: | To promote the application of ultra-high performance concrete(UHPC) deep beams, shear performance tests were conducted on four UHPC deep beams by taking the concrete strength as the main parameter, and the C40 and C80 concrete deep beams were tested for comparison. The load-deflection curves, failure modes, reinforcement strains, crack patterns and ultimate loads of UHPC deep beams were analyzed. The method specified in the Code for Design of Concrete Structures(GB 50010—2010) was used to determine the shear strengths of six deep beam specimens, to discuss whether the current method for calculating the shear capacity of ordinary concrete deep beams is applicable to UHPC deep beams. Research result shows that the greater the concrete strength is, the greater the stiffness of the deep beam under the same load is. The stiffness of UHPC specimen in its elastic stage before the cracking increases slightly with the increase of steel fiber content. Similar to the C40 and C80 concrete deep beams, the UHPC deep beams exhibit bending-shear and web-shear cracks. When the load reaches 13%-22% and 18%-34% of the ultimate load, the two types of cracks appear successively. Beam and arch stress mechanisms are both present during the loading of UHPC deep beams. The beam stress mechanism dominates the early phases of loading process, whereas the arch stress mechanism dominates the latter stages of this process. The UHPC deep beams exhibit a large number of densely and concentrated cracks and undergo shear-compression failure, without showing any cracks in the inverted arch area above their supports. In contrast, the C40 and C80 concrete deep beams undergo diagonal compression failure, and cracks appear in the inverted arch area above their supports. The shear bearing capacity of test beam increases in an approximately exponential manner with the increase of concrete strength. When the concrete strength increases from C40 to C80 and C190, the shear bearing capacity increase by 30.76% and 201.92%, respectively. When using the method specified in the Code for Design of Concrete Structures(GB 50010—2010) to calculate the shear bearing capacities of UHPC deep beams, the calculated and experimental shear bearing capacities show an average ratio of 0.89 and a mean squared error of 0.15. Therefore, this method can be temporally used to calculate the shear bearing capacity of UHPC deep beams, until a more accurate calculation method is available. |
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