Kodsy Antony, Morcous George
Durham School of Architectural Engineering and Construction, University of Nebraska-Lincoln, 1110 S. 67th Street, Omaha, NE 68182-0816, USA.
Materials (Basel). 2022 Jul 8;15(14):4794. doi: 10.3390/ma15144794.
The use of Ultra-High-Performance Concrete (UHPC) in beams has been growing rapidly in the past two decades due to its superior mechanical and durability properties compared to conventional concrete. One of the areas of interest to designers is the elimination of transverse reinforcement as it simplifies beam fabrication/construction and could result in smaller and lighter beams. UHPC has a relatively high post-cracking tensile strength due to the presence of steel fibers, which enhance its shear strength and eliminate the need for transverse reinforcement. In this paper, UHPC shear test data were collected from the literature to study the effect of the following parameters on the shear strength of UHPC beams without transverse reinforcement: compressive strength, tensile strength, level of prestressing, longitudinal reinforcement ratio, and fiber volume fraction. Statistical analysis of test data indicated that level of prestressing and tensile strength are the most significant parameters for prestressed UHPC beams, whereas longitudinal reinforcement ratio and tensile strength are the most significant parameters for non-prestressed UHPC beams. Additionally, shear strength of the tested UHPC beams was predicted using five models: RILEM TC 162-TDF, 2003, Model Code, 2010, French Standard NF P 18-710, 2016, PCI-UHPC Structures Design Guide, 2021, and Draft of AASHTO Guide Specification for Structural Design with UHPC, 2021. Comparing measured against predicted shear strength indicated that the French Standard model provides the closest prediction with the least scatter, where the average measured-to-predicted strength was 1.1 with a standard deviation of 0.38. The Draft of AASHTO provided the second closest prediction where the average measured-to-predicted strength was 1.3 with a standard deviation of 0.64. The other three models underestimated the shear strength.
在过去二十年中，由于超高性能混凝土（UHPC）相较于传统混凝土具有卓越的力学性能和耐久性，其在梁中的应用迅速增加。设计师感兴趣的一个领域是取消横向钢筋，因为这简化了梁的制作/施工，并可能使梁更小、更轻。由于钢纤维的存在，UHPC具有相对较高的开裂后抗拉强度，这提高了其抗剪强度并消除了对横向钢筋的需求。本文从文献中收集了UHPC抗剪试验数据，以研究以下参数对无横向钢筋的UHPC梁抗剪强度的影响：抗压强度、抗拉强度、预应力水平、纵向配筋率和纤维体积分数。试验数据的统计分析表明，预应力水平和抗拉强度是预应力UHPC梁最重要的参数，而纵向配筋率和抗拉强度是非预应力UHPC梁最重要的参数。此外，使用五个模型预测了测试的UHPC梁的抗剪强度：RILEM TC 162 - TDF，2003年；《模型规范》，2010年；法国标准NF P 18 - 710，2016年；PCI - UHPC结构设计指南，2021年；以及AASHTO超高性能混凝土结构设计指南草案，2021年。实测抗剪强度与预测抗剪强度的比较表明，法国标准模型提供的预测最接近，离散度最小，实测强度与预测强度的平均值为1.1，标准差为0.38。AASHTO指南草案提供的预测次之，实测强度与预测强度的平均值为1.3，标准差为0.64。其他三个模型低估了抗剪强度。
