A strength model based on the compression zone failure mechanism was developed to predict the punching shear strength of concrete footings without transverse reinforcement. The proposed model assumes that the punching shear at a critical section is primarily counteracted by the compression zone of intact concrete at the footing. According to the material failure criteria of concrete, part of the compression zone failed by concrete crushing and the remaining part failed by inclined tensile cracking. In addition, the shear capacity of the concrete in the compression zone was evaluated considering the compressive normal stress developed by the flexural action of the footing. The strength model can be used for squat concrete footings with a low shear span to depth ratio as well as slender footings. The proposed model was verified by applying it to existing test specimens. The predictions of the proposed model demonstrated very good agreement with the test results and the model was found to be a better predictor than current design codes, specifically ACI 318-14 and KCI 2012.

中文翻译：

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基于压缩带破坏机理的混凝土基础冲孔强度

建立了基于压缩区破坏机制的强度模型，以预测无横向加固的混凝土基础的冲剪强度。所提出的模型假设，关键部位的冲切剪切力主要由基础处完整混凝土的压缩区抵消。根据混凝土的材料破坏准则，压缩区的一部分因混凝土破碎而失效，其余部分因倾斜拉伸裂纹而失效。另外，考虑到基础的挠曲作用所产生的压缩法向应力，评估了压缩区内混凝土的剪切能力。强度模型可用于剪切比与深度之比低的蹲式混凝土基础以及细长的基础。通过将其应用于现有的测试样本来验证所提出的模型。建议模型的预测结果与测试结果非常吻合，并且该模型比当前的设计规范（尤其是ACI 318-14和KCI 2012）具有更好的预测能力。