本論文對以纖維強化塑膠（FRP）貼附於梁底層之抗彎補強方法採填充心材方式增加梁深以提高抗彎強度方式進行改良。整體研究除對結構之強度、剛度、撓度、韌性等提出分析理論外，也以實驗驗證此一新式的補強工法之改良效果。 由實驗結果發現，只要補強試體可達最底層FRP拉斷之破壞模態，則梁斷面不符合平面維持平面的情形只造成FRP拉斷之延遲效應；對理論分析所預期之極限彎矩強度並不造成折減，仍能達到提高梁極限彎矩之效果。 本論文之研究證明以三明治進行梁構件彎矩補強的構想為實際且可行。但是心材和RC梁之間的相對變形及各種不同錨定方式，所造成之複雜行為，仍須做更進一步之探討，才可發展成一有用之補強方法。 In this thesis, a new structural strengthening technique was developed to improve the load carrying capacity of RC beam. Bonding a sandwich plate on the tensile side of the RC beam can increase the effective depth of the beam. The ultimate strength, bending rigidity, deflection and ductility of this strengthened beam were studied analytically and experimentally. It was found from experiments that the ultimate load predicted by the theory could be retained if the fiber breakage mode can occur. Through this study, one can realize that this new strengthening technique that sandwiches core material between FRP layers can effectively increase the load carrying capacity of RC beam compared with the beam with same layers of FRP but no core material. However, the relative deformation due the types of anchorage arrangement should be studied further before any design method is proposed.