考虑剪跨比的新加梁与原混凝土界面承载力计算理论研究
首发时间:2020-06-22
摘要:分析课题组已进行的不同剪跨比下新加梁与原混凝土界面承载力试验,结果表明:随着剪跨比λ的增大,截面正应力增大,新加梁与原混凝土界面承载力减小。达到极限承载力时,受拉纵筋均达到屈服;当λ≤2时,界面开裂,发生剪切破坏;当λ>2时,界面处较小受压区高度混凝土压碎,发生受弯破坏。基于新加梁端界面破坏机制及受力性能影响因素分析,提出了考虑新加梁受拉纵筋抗力和剪跨比λ影响的新加梁与原混凝土界面承载力计算模型。由试验数据分析,建立了反映剪跨比影响的新加梁与原混凝土界面承载力计算公式。通过大量已有试验结果对比分析,验证了所提新加梁与原混凝土界面承载力计算公式的准确性和适用性。基于可靠性分析,建立了满足可靠度要求的新加梁与原混凝土界面承载力计算公式。
关键词: 结构工程 结构加固 新加梁 界面承载力 剪跨比 理论计算
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Theoretical study on bearing capacity calculation of interface between newly added beam and original concrete considering shear-span ratio
Abstract:The bearing capacity of the interface between the newly added beam and the original concrete under different shear span ratio has been tested by our group, and the analysis results show that with the increase of shear span ratio, the section normal stress increases, and the bearing capacity of the interface between the newly added beam and the original concrete decreases. The longitudinal bars can be yield when the load reaches to the ultimate bearing capacity. When λ≤2, the interface cracked and shear failure occurred. When λ>2, the concrete is crushed at a small height of the compression zone at the interface and bending failure occurred. Based on the analysis of the failure mechanism and the influencing factors of the mechanical performance for the newly added beam end interface, a calculation model of the bearing capacity of the newly added beam and the original concrete interface was proposed, which considered the influence of the resistance of the longitudinal reinforcement and the shear span ratio. Through the analysis of experimental data, the bearing capacity calculation formula of the interface between the newly added beam and the original concrete is established, which reflects the influence of shear span ratio. The accuracy and applicability of the proposed formula for calculating the bearing capacity of the interface between the newly added beam and the original concrete are verified through the comparative analysis of a large number of existing test results. Based on the reliability analysis, a formula for calculating the bearing capacity of the interface between the newly added beam and the original concrete is established, which can meet the reliability requirements.
Keywords: structural engineering;structural strengthening newly added beam interfacial bearing capacity shear span ratio theoretical calculationkey
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