考虑混凝土贡献的修正变角桁架模型

发布时间：2018-03-27 20:15

本文选题：钢筋混凝土浅梁　切入点：尺寸效应　出处：《土木工程学报》2017年06期

【摘要】：为提高有腹筋RC(钢筋混凝土)浅梁抗剪承载力的预测准确性和稳定性,提出一种考虑混凝土贡献的修正变角桁架模型。首先,基于变角桁架模型得到箍筋的抗剪贡献值计算公式,并结合塑性下限定理确定斜裂缝倾角的取值;其次,通过混凝土浅梁受压区的劈裂破坏模式得到混凝土项的抗剪贡献值计算公式,并利用尺寸效应系数考虑了混凝土项的脆性破坏特征;最后,将箍筋项和混凝土项提供的抗剪承载力进行叠加,建立有腹筋RC浅梁抗剪承载力计算公式。基于有腹筋RC浅梁抗剪承载力试验数据库ACI-DAfStb对本文、GB50010、ACI及AASHTO规范中抗剪计算公式的预测准确性进行对比评估,结果表明:文中抗剪承载力公式不仅能够体现配筋率、剪跨比和混凝土强度等主要抗剪参数的影响规律,还能考虑尺寸效应和斜裂缝倾角对抗剪承载力的修正;同时,在抗剪承载力预测准确性和稳定性方面,相对规范方法有所较高。
[Abstract]:In order to improve the web reinforcement RC (reinforced concrete) shallow beam shear capacity prediction accuracy and stability, this paper proposes a modified variable angle truss model considering the concrete contribution. First, a variable angle truss model obtained shear stirrup contribution value calculation formula based on, combined with the plastic limit theorem to determine the value of criticalshearangle. Secondly, through the concrete beam; shallow compression zone splitting failure mode is the shear contribution of concrete calculation formula, and the size effect coefficient considering the concrete characteristic of brittle failure; finally, will provide the stirrup and concrete shear stacking capacity, establish the calculation formula of stirrups RC shear capacity of beams. Based on the shear stirrups RC shallow beam bearing capacity test database ACI-DAfStb on this article, GB50010, ACI and AASHTO in the specification of shear prediction accuracy calculation formula were compared to assess the results table Ming: the formula of shear bearing capacity can not only reflect the reinforcement ratio, shear span ratio and concrete strength of main shear parameters, but also consider the size effect and correction of criticalshearangle shear capacity; at the same time, the shear bearing capacity prediction accuracy and stability, relatively high specification method.

【作者单位】：南京林业大学;
【基金】：国家自然科学基金(51208262) 江苏省自然科学基金(BK20151520) 江苏高校优势学科建设工程资助项目(PAPD) 江苏高校品牌专业建设工程项目(PPZY2015A063)
【分类号】：TU375.1

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