摘要
重载铁路部分32 m预应力混凝土T梁腹板斜向开裂现象日渐突出。为了深入探究铁路典型T梁斜截面抗剪性能,设计制备了1片跨度5.0 m的钢筋混凝土模型梁,通过静载试验研究混凝土抗裂性能和斜截面开裂后梁体的力学性能。结果表明:不考虑塑性系数时纯弯段混凝土弯曲抗拉强度大于轴心抗拉强度,腹板斜截面混凝土抗拉强度与混凝土轴心抗拉强度接近;不考虑塑性影响的剪弯段混凝土弯曲抗拉强度略低于轴拉强度;模型梁斜截面开裂后,在外荷载作用下斜裂缝宽度变化沿梁高方向的分布无明显规律。当荷载达到剪压破坏抗剪承载力理论值时,箍筋屈服,梁体未发生剪压破坏。经过3次循环静载作用后,梁体纵筋未屈服,纯弯段上缘混凝土仍处于正常工作状态。
The phenomenon of oblique cracking in the web of 32 m prestressed concrete T-girder of heavy haul railway has become increasingly prominent.In order to further explore the shear resistance of typical railway T-girder oblique section,a reinforced concrete model girder with a span of 5.0 m was designed and prepared.The concrete crack resistance and the mechanical properties of the girder after oblique section cracking were studied through static load tests.The results show that the flexural tensile strength of concrete in pure bending section is greater than the axial tensile strength without considering the plastic coefficient,and the tensile strength of concrete in oblique web section is close to the axial tensile strength of concrete.The flexural tensile strength of concrete in shear bending section without considering the influence of plasticity is slightly lower than the axial tensile strength.After the oblique section of the model girder cracks,there is no obvious regularity in the distribution of the width change of the oblique crack along the girder height direction under external load.When the load reaches the theoretical value of shear bearing capacity for shear compression failure,the stirrups yield,and the girder is not damaged by shear compression.After three cycles of static loading,the longitudinal reinforcement of the girder did not yield,and the concrete at the upper edge of the pure bending section is still in normal working condition.
作者
王振
牛斌
葛凯
许见超
袁磊
赵体波
WANG Zhen;NIU Bin;GE Kai;XU Jianchao;YUAN Lei;ZHAO Tibo(Postgraduate Department,China Academy of Railway Sciences,Beijing 100081,China;Railway Engineering Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)
出处
《铁道建筑》
北大核心
2023年第3期63-68,共6页
Railway Engineering
基金
中国铁道科学研究院集团有限公司基金(2021YJ201)
国能朔黄铁路发展有限责任公司项目(GJNY-22-85)。
关键词
钢筋混凝土梁
静载试验
斜截面
抗裂性能
裂缝宽度
reinforced concrete girder
static test
oblique section
crack resistance
crack width
