纖維貼片補強鋼筋混凝土梁受載行為研究

Abstract

本文係針對纖維複合貼片補強鋼筋混凝土梁之受載行為、破壞模式進行探討，並依一般梁撓曲理論建立破壞過程中各階段彎矩強度分析模式。 以試驗探討不同纖維複合貼片（玻纖貼片、碳纖貼片）及補強型式（I-Jacket型式、Ｕ型包覆型式）下，梁試體受載之載重-梁中點位移關係及載重-鋼筋與纖維應變關係。試驗結果顯示，同層補強下以碳纖複合貼片補強較纖複合貼片有較高之極限強度、撓曲勁度、極限變位特性，但卻於殘餘強度上表現較弱；以Ｕ型包覆補強較之 I-Jacket 型式補強亦可獲得上述相同結論。 彎矩強度之分析模式建立則依開裂、降伏、極限三階段，依彈性理論及 ACI318-95 建議之極限分析模式進行，後並引入“概念判斷構件破壞控制模式”；並以分析之各階段彎矩、曲率計算理論變位，經由與試驗獲得之載重-位移曲線比較，證明此分析模式應為可行。

This paper was directed to investigate the loaded behavior and failure modes of R.C. beams strengthened with fiber reinforced plastics(FRP). Followed the general flexural theory, the moment strength analytical model was established. An experiment was conducted to investigate the relationships of load-deflection and load-strain of specimens strengthened with various FRP sheets(glass fiber sheets and carbon fiber sheets)and strengthened types(I-Jacket type and U type). Experimental results indicated that, with the same strengthened layer, specimens strengthened with CFRP sheets behaved with characteristics of higher ultimate strength, flexural stiffness, and ultimate deflection, but less residual strength. Considering the cracking, yielding, and ultimate state of specimens, the analytical flexural strength model was established by following the elastic theory and ACI 318-95 code suggested method. A "balance FRP ratio" concept was incorporated to ascertain the control failure mode of the member. The deflection derived from the moment-curvature relation was compared with test results and showed good agreement.