超高性能混凝土U形包裹加固钢筋混凝土T梁研究

Research on ultra-high performance concrete U-shaped wrapped reinforced concrete T-beams

为改善简支T梁损伤累积导致的抗弯、抗剪承载能力不足等问题,提出了采用超高性能混凝土(UHPC)U形三面包裹T梁底板和腹板的加固方案,建立了T梁加固前和采用加固后的非线性有限元模型,进行了四点弯曲试验及抗剪试验数值模拟,通过对比加固前后荷载-位移曲线,分析了加固前后的抗弯、抗剪性能。结果表明:基于ABAQUS软件模拟T梁抗弯剪试验的准确性较高,可用于后续桥梁的加固分析;采用C120、C150强度等级UHPC加固后的T梁在极限抗弯承载能力上较加固前分别提升了69%、77%;在相同剪跨比下,加固后T梁的抗剪承载力和抗变形性能显著提升;加固后有效地抑制了损伤的发展,为T梁提供了较大安全储备。

In order to improve the problems of insufficient flexural and shear bearing capacity caused by the accumulation of damage in a simply supported T-beam,a reinforcement scheme of reinforcing the bottom plate and web of reinforced concrete T-beam with U-shaped wrapped reinforcement was proposed.A nonlinear finite element model of the T-beam before strengthening and after strengthening with UHPC reinforcement was established,and numerical simulations of four-point bending test and shear test were carried out to compare the load-displacement curves before and after strengthening,and the differences in flexural and shear performance between the two were analyzed.The results indicate that the accuracy of simulating T-beam flexural and shear tests based on ABAQUS software is high and can be used for subsequent bridge reinforcement analysis.The ultimate flexural load capacity of the T-beam after strengthening with C120 and C150 UHPC is increased by 69%and 77%respectively compared with that before reinforcement.The shear load capacity and deformation resistance of the reinforced simply-supported T-beam can be significantly improved under the same shear-to-span ratio.The UHPC reinforcement effectively inhibits the development of damage,and provides a larger safety reserve for the reinforced concrete T-beam.