鋼骨鋼筋混凝土(SRC)短柱軸壓行為與圍束效應之數值模擬研究

Abstract

近年來陸續有許多大尺寸的鋼骨鋼筋混凝土（Steel Reinforced Concrete，SRC）柱之試驗結果出現，證實SRC柱具備優良的抗壓強度與韌性，且SRC柱中之鋼骨可以對其所包覆之混凝土發揮良好的圍束效應。然而，由於SRC構造設計之參數較為複雜，若要逐一進行軸壓試驗來探討各設計參數對軸壓行為之影響，則勢必需要耗費龐大的人力、時間及金錢，且由於試驗設備及場地等限制，常常僅能針對一部份設計參數進行試驗，而無法作較為詳細的探討。 為了有效運用資源並節省人力、時間及金錢，本研究針對SRC短柱之「軸壓行為」與「圍束效應」進行數值模擬分析。根據文獻調查顯示，ANSYS為一功能強大的有限元素分析軟體，其在鋼結構及RC結構之分析應用上已有相當之成果，故本研究乃採用ANSYS軟體作為數值模擬分析之工具。 本研究運用ANSYS軟體建立SRC短柱受軸壓作用之分析模型，並與一系列SRC短柱之試驗結果互相比對驗證。最後針對SRC柱之「圍束箍筋需求量」進行深入探討，經由分析證實SRC柱內之鋼骨翼板確實能夠對其所包覆之混凝土發揮圍束貢獻，大約可額外提升20％至33％的混凝土抗壓強度。本研究並提出一套新的SRC柱圍束箍筋需求量之計算公式，以提供學術界與工程界參考。

During the last decade, test results of full-scale steel reinforced concrete (SRC) columns obtained by previous researchers have demonstrated satisfactory performance both in strength and ductility. In addition, special recognition has been accredited to the superior concrete confinement effect provided by the steel section embedded in the SRC column. However, due to the fact that the cost of conducting experiment on full-scale specimens is very expensive and time consuming, an alternative approach using the numerical simulation technique has become increasingly desirable. It is the objective of this study to utilize the highly recognized finite element method (FEM) software ANSYS to numerically simulate the mechanical behavior and confinement effect of the SRC columns. In the first stage, this study generated and analyzed a FEM model to simulate the SRC test specimen. The numerical result was compared to the SRC test data to confirm the validity of the FEM model. In the second stage, the parameters related to the design of the SRC columns were investigated using the FEM model obtained from the previous stage. The major parameters in this numerical study included the axial strength, ductility and the confinement effect. The numerical results showed that the steel section in SRC short columns can provide effective confinement to the concrete and enhance the concrete compressive strength up to 20 to 33 percent. Therefore, a new design method was proposed in this study to account for the confinement effect provided by the steel section embedded in the SRC column.