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对6个受火后高强钢筋混凝土连续T形梁试件分别采用粘贴钢板加固与螺栓锚接钢板加固,并研究其力学性能和破坏形态。结果表明:受火后高强钢筋混凝土连续T形梁粘贴钢板加固后,承载力提高39.1%~58.2%,破坏挠度降低17.8%~53.2%;采用螺栓锚接钢板加固后,承载力提高36.7%,破坏挠度仅下降4.4%。采用螺栓锚接钢板加固后,初始弯曲刚度与未受火对比试件相当;粘贴钢板加固后,初始弯曲刚度较未受火对比试件明显增大。距跨中越近,梁底钢板拉应变越大,应变变化梯度越大。受火后梁底粘贴一层钢板或螺栓锚接一层钢板加固后,位移延性系数提高53.4%~62.0%、能量延性系数提高62.6%~72.6%;受火后梁底和梁顶中支座附近各粘贴一层钢板加固后,其位移延性系数降低8.2%、能量延性系数降低7.2%。采用折算面积法计算钢板加固受火后高强钢筋混凝土连续T形梁的承载力误差为-0.2%~13.2%,符合工程精度要求。
Six specimens of high tensile strength concrete continuous T-beams subjected to fire were respectively reinforced with bonded steel plates and bolted steel plates, and their mechanical properties and failure modes were studied. The results show that the bearing capacity increases by 39.1% -58.2% and the failure deflection decreases by 17.8% -53.2% after being strengthened by the continuous T-shaped beam bonded steel plate after fire; the bearing capacity increases by 36.7% Destruction deflection decreased only by 4.4%. The initial bending stiffness is equivalent to that of the non-fire contrast test specimen after the steel bolting plate is strengthened. The initial bending rigidity of the steel plate strengthened with the adhesive steel is obviously higher than that of the non-fire test specimen. The closer the span is to the mid-span, the greater the tensile strain at the bottom of the beam and the greater the gradient of strain change. After being strengthened by fire, a layer of steel plate or bolt anchored with a layer of steel plate is attached to the bottom of the fire, the displacement ductility coefficient is increased by 53.4% -62.0% and the energy ductility coefficient is increased by 62.6% -72.6%. After the fire, After the steel plate is strengthened, the displacement ductility coefficient decreases by 8.2% and the energy ductility coefficient decreases by 7.2%. The calculated area error of bearing capacity of steel reinforced concrete continuous T-beam is -0.2% ~ 13.2%, which meets the requirements of engineering accuracy.