CFRP補強含剪力筋RC梁之試驗研究

The Experimental Study of RC Beams with Shear Reinforcement Strengthened with CFRP

鄭志勤(Chih-Ching Cheng)

指導教授 ： 林至聰

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00073

摘要

RC梁構件的剪力強度來源，主要為混凝土與主鋼筋的剪力效應Vc及剪力筋的剪力效應Vs，Vc加Vs則為完整的RC梁剪力強度；若再加上CFRP剪力補強的剪力效應Vp，三者交互影響下，其行為更趨複雜且無法容易預測。檢視過去許多CFRP剪力補強的研究，皆顯示其對於剪力強度的預測不夠精確；此外CFRP剪力補強的經驗公式在實際的RC梁應用上，其剪力效應的預測仍顯得模糊不確定。因此在Vc、Vs及Vp三者的設計分析上實有做進一步檢討的需要。
本論文的研究目的及範圍：首先以試驗來檢討現行規範對於RC梁之剪力性能；第二，以試驗來研究分析在不同的剪力筋量下，CFRP補強RC梁剪力強度的關係，進而檢討補強效益及勁度變化；最後依試驗數據驗證檢討現行的規範公式及文獻經驗式，將規範設計值及文獻經驗式所得之計算值與本次試驗值相比較，提供給設計使用者參考。
研究結果顯示：ACI規範設計值（採Vc＝簡化式及精確式兩項）確實較為保守。根據CFRP剪力補強之效能分析，顯示CFRP剪力補強確實可以增加RC梁之剪力強度及提昇相對勁度，但卻隨著剪力筋量之增加而降低其補強效果。此外，當剪力筋間距大於1/2d之配置下，顯示有較佳的補強效果；而剪力筋間距小於或等於1/2d之配置下，可能由於本次研究中試體尺寸之關係，造成補強效果有限。

關鍵字

剪力筋 ； 剪力補強 ； CFRP ； RC梁 ； 剪力筋間距

並列摘要

The shear strength of RC Beams is mainly composed of Vc, the shear mechanism of concrete and rebars, and Vs, the shear mechanism of shear reinforcement. Vc plus Vs would be the full shear strength of RC Beams. Furthermore, when coupling with Vp, the shear mechanism of shear retrofitted by CFRP, the behaviors under the interactions among Vc, Vs, and Vp are more complex and uneasy to predict. Common limitaions often occur in most of previous studies of shear retrofitted by CFRP, which leads to impact the preciseness of the prediction of the shear strength. In addition, empirical formulas in practical applications of RC Beams still seem fuzzy and full of uncertainty. Therefore, it's necessary to analyze the design of Vc, Vs, and Vp.
The purpose and scope of this research is, first of all, to review the existing codes against the shear performance of RC beams with experiments; secondly, to study the relationship between CFRP and the shear strength of RC beams under different shear reinforcement spacings, and then to review the retrofitted bebefit and stiffness change; finally, to review the existing codes and the empirical formulas based on the experimental data, and then to provide comparative results to designers.
The test results indicated that the designs of ACI code（by Vc＝simplified formula and exact formula）are indeed more conservative. Based on the analysis of shear retrofitted by CFRP, it has been proven that shear retrofitted by CFRP can indeed increase the shear strength and the stiffness of RC beams; however, with the increasing amounts of shear reinforcement, retrofitted benefit would be negatively impacted accordingly. In addition, greater retrofitted benefit can be achieved when the shear reinforcement spacing is greater than 1/2d; on the other hand, retrofitted benefit would be limited when the shear reinforcement spacing is less than or equal to 1/2d, which may result from the size of specimens.

並列關鍵字

Shear Reinforcement ； Shear Retrofit ； CFRP ； RC Beam ； Shear Reinforcement Spacing

參考文獻

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