本研究旨在探討尺寸效應以及配筋量(1.7%及0.6%)對於貫穿剪力之影響，以其日後對設計承受高軸壓鋼筋混凝土設計與製作有所幫助。試體製作方面，製作3個三層鋼筋以及1個單層鋼筋的小型樁帽試體，再依邊長比例放大2倍，分別製作3個三層鋼筋以及1個單層鋼筋的中型、大型樁帽試體，總共12個。
由實驗結果顯示如下。
三層鋼筋的試體，有效深度增加時，三層鋼筋試體強度不會隨其有效深度之倍率上升 ，其強度隨著有效深度增加而有曲線折減產生；單層鋼筋的試體，有效深度增加時，單層鋼筋試體強度不會隨其有效深度之倍率上升，其強度隨著有效深度增加而上升，但上升幅度越趨平緩，在有效深度從500mm達到1000mm時，試體強度還有上升現象，有尺寸效應產生。
低主筋比試體之破壞模式為由鋼筋所提供的拉桿強度控制，高主筋比試體之破壞模式為混凝土所提供的壓桿承壓強度控制。
根據壓拉桿模式所計算之極限強度，如為低主筋比試體不具尺寸效應，但對於高主筋比試體，則應考量尺寸效應之影響。
本研究根據實驗結果，提出混凝土壓桿承壓強度之尺寸效應修正方式，可有效評估試體最大載重。

The purpose of this expriment was to investigate the size effect and the ratio of reinforcement (1.7% and 0.6%) in the punching shear, which will benefit to design and manufacture the high strength reinforced concrete subjected to the high axial force in the future.For the manufacture of the specimen, we made three small pile caps which had three-layer rebar and one small pile caps which had one-layer rebar. We made four medium-sized pile caps which are twice as big as the small specimen and four large-sized pile caps which are four-times as big as the small pile caps.For the three-layer rebar specimen, when the effective depth was increased, the strength will not increase with the increase of the effective depth, and the increase of strength had a curve reduction. For the one-layer rebar specimen, when the effective depth is increased, the strength will not increase with the increase of the effective depth, and the increase of strength had a curve reduction.as the effect depth was increase from 500mm to 1000mm,the increase of strength had a little rise.The failure mode of the specimen which had low-reinforcement ratio was controlled by the strength of the tie rod provided by the steel bar,and the failure mode of the specimen which had low reinforcement ratio was controlled by the compression strut rod.provide by the concrete.According to the ultimate strength calculated by strut-and-tie model, it seemed that low-reinforcement-ratio specimen has no size effect ,and the high-reinforcement-ratio specimen should be consider with size effect.Based on the experimental results, this study proposes a method for correcting the size effect of the compressive strength of concrete strut rib, which can effectively evaluate the maximum load of the specimen.

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