鋼骨鋼筋混凝土（SRC）梁抗彎及抗剪試驗與力學行為研究

Abstract

本研究藉由一系列大尺寸包覆型鋼骨鋼筋混凝土（SRC）梁試驗，以探討其在受彎矩及剪力時之力學行為。試體之設計參數有鋼骨與RC之合成狀態、鋼骨翼板或腹板加設剪力釘以及翼寬比（bf/B）等，主要用以探討美國ACI規範之「應變相合法」及日本AIJ-SRC規範之「強度疊加法」用於計算SRC梁極限抗彎強度之合理性及SRC梁受剪力之下破壞模式。此外，本研究並探討剪力釘對SRC梁撓曲行為及繫拱行為（Tie-Arch Action）之影響。 在抗彎力學特性方面，本研究根據實驗觀察比較SRC梁與普通RC梁從彈性階段、勁度開始軟化到破壞時之載重-位移關係，並以詳細之應變計資料說明二者力學行為之差異性。在抗剪力學特性方面，試驗結果顯示SRC梁可能由於過大之翼寬比導致鋼骨翼板與混凝土介面發生剪力握裹破壞（Shear Bond Failure），導致SRC梁無法達到預期之極限強度。但研究結果亦顯示在鋼骨翼板加銲剪力釘可以減少SRC梁壓力緣混凝土的開裂現象，而有助於避免SRC梁發生剪力握裹破壞。在短梁方面，由於繫拱現象與撓曲行為不同，實驗結果顯示SRC短梁中鋼骨翼板上之剪力釘並無傳遞撓曲行為所需之水平剪力之功能，故加銲剪力釘無法增加SRC短梁之極限強度，但研究顯示在翼板或腹板加銲剪力釘後有助於提高SRC短梁之韌性。本研究之實驗結果有助於深入瞭解SRC梁之抗彎與抗剪強度及其力學行為，對於後續之相關研究與SRC梁之強度預測方法之發展等方面具有正面之參考價值。

A series large-scale steel reinforced concrete（SRC）specimens were tested with vertical monotonic load to study mechanical behavior of SRC beams. The suitability of the design approaches used in the ACI-318 code (1995) and the AIJ-SRC code (1987) are investigated. Major variables studied include the composite action between steel and RC and the flange width ratio（bf/B）. In addition, the influence of shear stud on flexural behavior and tie-arch action of SRC beam is also discussed. This study compares the differences of the strain distribution and the load- displacement relationship between SRC and RC beams according to the data recorded from the tests. Experimental results indicate that the use of shear stud has little improvement on the ultimate flexural strength, but it is helpful for avoiding shear bond failure. Test results also reveal that using of shear stud on the steel flange of SRC short beam has little improvement on the ultimate shear strength. This in mainly because the shear capacity of SRC short beam is controlled by the tie-arch action. However, the application of shear stud on the steel flange or web is found to be helpful for improving the ductility of SRC short beams.