焊接锚固纵筋钢纤维增强高强混凝土牛腿抗剪模型分析

Analysis of Shear Model for Steel-Fiber-Reinforced High-Strength Concrete Corbels with Welded-Anchorage Longitudinal Reinforcement.

作者信息

Li Shu-Shan, Peng Die, Wang Heng, Zhang Feng-Jian, Li Hong-Mei, Xie Yi-Jun, Chen Ai-Jiu, Xie Wei

机构信息

School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou 450046, China.

Engineering Technology Research Center for Structural Vibration Control and Health Monitoring of Henan Province, Zhengzhou 450046, China.

出版信息

Materials (Basel). 2023 Jul 9;16(14):4907. doi: 10.3390/ma16144907.

DOI:10.3390/ma16144907

PMID:37512182

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10381473/

Abstract

According to the shear capacity test results of six steel-fiber-reinforced high-strength concrete (SFHSC) corbels with welded-anchorage longitudinal reinforcement under concentrated load, the effects of shear span ratio and steel fiber volume fraction on the failure mode, cracking load and ultimate load of corbel specimens were analyzed. On the basis of experimental research, the shear transfer mechanism of corbel structure was discussed. Then, a modified softened strut-and-tie model (MSSTM), composed of the diagonal and horizontal mechanisms, was proposed, for steel-fiber-reinforced high-strength concrete corbels. The contributions of concrete, steel fiber and horizontal stirrups to the shear bearing capacity of the corbels were clarified. A calculation method for the shear bearing capacity of steel-fiber-reinforced high-strength concrete corbels was established and was simplified on this basis. The calculation results of the model were compared with the test values and calculation results of the GB50010-2010 code, the ACI318-19 code, the EN 1992-1-1 code and the CSA A23.3-19 code. The results showed that the concrete corbel with small shear span ratio mainly has two typical failure modes: shear failure and diagonal compression failure. With the increase in shear span ratio, the shear capacity of corbels decreases. Steel fiber can improve the ductility of a reinforced concrete corbel, but has little effect on the failure mode of the diagonal section. The calculated values of the national codes were lower than the experimental values, and the results were conservative. The theoretical calculation values of the shear capacity calculation model of the corbels were close to the experimental results. In addition, the model has a clear mechanical concept considering the tensile properties of steel-fiber-reinforced high-strength concrete and the influence of horizontal stirrups, which can reasonably reflect the shear transfer mechanism of corbels.

摘要

通过对6个集中荷载作用下焊接锚固纵筋的钢纤维高强混凝土（SFHSC）牛腿的抗剪承载力试验结果，分析了剪跨比和钢纤维体积分数对牛腿试件破坏模式、开裂荷载和极限荷载的影响。在试验研究的基础上，探讨了牛腿结构的抗剪传力机理。然后，针对钢纤维高强混凝土牛腿，提出了一种由斜压和水平机理组成的改进软化压杆-拉杆模型（MSSTM）。明确了混凝土、钢纤维和水平箍筋对牛腿抗剪承载力的贡献。建立了钢纤维高强混凝土牛腿抗剪承载力的计算方法，并在此基础上进行了简化。将该模型的计算结果与GB50010-2010规范、ACI318-19规范、EN 1992-1-1规范和CSA A23.3-19规范的试验值和计算结果进行了比较。结果表明，剪跨比小的混凝土牛腿主要有两种典型破坏模式：剪切破坏和斜压破坏。随着剪跨比的增大，牛腿的抗剪承载力降低。钢纤维可以提高钢筋混凝土牛腿的延性，但对斜截面破坏模式影响较小。各国规范的计算值均低于试验值，结果偏于保守。牛腿抗剪承载力计算模型的理论计算值与试验结果接近。此外，该模型力学概念明确，考虑了钢纤维高强混凝土的抗拉性能和水平箍筋的影响，能合理反映牛腿的抗剪传力机理。