中剪跨鋼纖維混凝土梁剪力強度預測研究

Abstract

鋼纖維混凝土的發展歷史已有數十年的歷史，透過在混凝土中添加鋼纖維，具有提高混凝土抗拉強度、提高彈性模數、發展韌性行為以及改善破壞機制等效果。由於抗拉強度以及韌性行為的提升，使的鋼纖維混凝土梁在承受剪力時有極佳的效果。有許多研究已指出在添加充足的鋼纖維時，剪力鋼筋的配置量可以大幅減少甚至免去。由於在窄小或不規則斷面配置剪力鋼筋往往是困難且不經濟的，因此若鋼纖維能夠取代剪力鋼筋的使用，許多現有在混凝土結構幾何形狀設計上的限制也可能得到突破。 為了能夠使鋼纖維混凝土更普遍的應用在實務上，當前所需要的是量化鋼纖維混凝土之效益，以加速相關規範之訂定。本研究著重於評估彎鉤型鋼纖維混凝土梁之剪力強度，由於目前已有許多學者對於鋼纖維混凝土梁提出剪力強度預測公式，本研究針對這些公式一一分析其特性並比較精確度。此外，本研究亦蒐集多筆文獻中所進行的剪力試驗，整理成資料庫，用以推導並建議新的彎鉤型鋼纖維混凝土梁剪力強度設計公式與適用於中剪跨梁之剪力強度預測公式。最後，為了驗證此二公式之準確性以及尋找適當之改善方法，第五章亦設計了建議試驗以供未來進行試驗。

The use of steel fiber in concrete has long been recognized to increase concrete strength and ductility. Previous research indicates that conventional stirrups can be eliminated by adding a sufficient amount of steel fiber in the concrete. Because shear reinforcement is hard to design in the member with narrow or irregular section, use steel fiber as shear reinforcement may break many geometric constraints on concrete design. In order to make fiber reinforced concrete (FRC) for more general use, the current need is to quantify the effectiveness of steel fiber. The purpose of this investigation is to evaluate the shear strength of FRC. Since there are already many researchers proposed their own equations for predict the shear strength of FRC, this study analyzed each equations and compared the accuracy. In addition, this study also collected many shear test data, constructed the database to derive and propose new equation. In order to exam the accuracy of the proposed equation and to find appropriate ways to improve, the recommended test also designed in chapter 5.