鋼骨鋼筋混凝土(SRC)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） 柱之實驗結果出現，顯示SRC 柱具有良好的抗壓強度與韌性。再者，由於SRC 柱 中之鋼骨可以對混凝土提供良好的圍束作用，因此有助於提昇SRC 柱之軸壓強度， 亦有助於降低SRC 柱之圍束箍筋用量。 然而，由於SRC 構造結合了鋼骨與RC，其設計參數較多且變化亦較為複雜， 若要針對各設計參數逐一進行SRC 柱試驗來探討其對力學行為與圍束效應之影 響，則勢必要耗費龐大的人力、時間及金錢；且由於實驗設備及場地等限制，常常 僅能針對一部份參數進行實驗，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，本研究擬針對SRC 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 為一功能頗 強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不錯之成果，故 本研究擬選用ANSYS 軟體作為模擬SRC 柱力學行為之分析工具。 本研究首先將運用ANSYS軟體建立SRC柱之數值分析模型，以模擬SRC柱之軸 壓強度與位移之關係曲線，並與一系列大尺寸SRC柱實驗結果互相比較，以驗證其 可靠度與準確性。然後，再針對SRC柱之重要設計參數逐一探討，包括材料強度、 鋼骨斷面型式（箱型、H型、十字型、T型）、鋼骨翼板寬度變化、鋼骨斷面寬厚比、 箍筋之間距與需求量等。最後，本研究擬針對SRC柱之「鋼骨對混凝土的圍束效應」 進行深入分析，以期更合理的評估SRC柱之箍筋需求量。本研究期望能夠提出一套 新的SRC柱「圍束箍筋用量」之設計公式，以提供學術界與工程界參考。

During the last decade, many 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 called ANSYS to numerically simulate the mechanical behavior and confinement effect of the SRC columns. In the first stage, a FEM model simulates the SRC test specimen will be generated and analyzed. The numerical results will be 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 will be investigated using the FEM model obtained from the previous stage. The major parameters to be investigated in this numerical study include the variations of the material property, the sectional dimension and the shape of the steel section. Also investigated will include the axial strength, ductility and the confinement effect of the steel section. It is hoped that the results of this numerical investigation will provide further understanding on the mechanical behavior of the SRC columns. Finally, a new design method will be proposed to account for the confinement effect provided by the steel section embedded in the SRC column.