Punching shear tests on symmetrically reduced slab quarters
Punching shear tests on symmetrically reduced slab quarters
复制标题
对称缩小板坯的冲切试验
DOI：
10.1002/suco.201400022
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发表时间：
2014
影响因子：
3.2
通讯作者：
Sommer
中科院分区：
文献类型：
--
作者：
Winkler;Rohländer;Sommer
大型钢筋混凝土构件（如有效深度较大的梁或板）的实验具有挑战性，而且很少进行，尤其是由于大量的材料和资金投入。然而，这些实验的结果是迫切需要的，因为临界尺寸效应影响剪切和冲切破坏类型。在鲁尔波鸿大学混凝土结构研究所（RUB），根据“通过缩小尺寸来扩大尺寸”的原则设计了一种创新的测试装置。它将对称性简化-数值模拟中的标准功能-转移到实验中。因此，试验荷载和恒载与对称度成比例地显著降低，从而在给定的试验设施内产生较大的试样。该装置可以对对称截面的混凝土构件进行测试--对分梁或四分之一板--同时意味着相应的，即全尺寸构件的荷载-变形行为，只需将荷载分解为轴对称度的两倍。本文介绍了测试四分之一板的开发过程中的单个步骤，包括具有滑动平面的模块化支撑结构和弯曲钢筋的锚固以及混凝土试样本身，与对称平面互连，测量技术及其具体装配。第一个原型测试的结果证明了失效模式、裂纹模式和运动学的普遍适用性。然而，极限冲切载荷仍然略高。
Experiments on large‐scale reinforced concrete members such as beams or slabs with large effective depths are challenging and – not least due to the extensive material and financial input – rarely performed. However, results from such experiments are desperately needed, as critical size effects affect shear and punching shear failure types. At the Institute of Concrete Structures at Ruhr‐Universität Bochum (RUB), an innovative test setup was devised following the principle of “upsizing by downsizing”. It transfers symmetry reductions – a standard feature in numerical simulations – to experiments. Thus, test loads and dead loads decrease markedly in proportion to the degree of symmetry, giving rise to larger specimens within given testing facilities. The setup enables tests on symmetrically sectioned concrete members – halved beams or quarters of slabs – concurrently implying the load‐deformation behaviours of corresponding, i.e. full‐size members, by simply factoring the loads with twice the axial symmetry degree.This paper presents the single steps in the development to test quartered slabs, including the modular support constructions with sliding planes and anchoring of the bending reinforcement as well as the concrete specimen itself, with interconnections to the symmetry planes, measuring techniques and its specific assembly. Results from a first prototype testing prove the general applicability for failure modes, crack patterns and kinematics. However, ultimate punching loads are still slightly overestimated.