METHOD TO INCREASE CAPACITY AND STIFFNESS OF REINFORCED CONCRETE BEAMS

Recent research into retrofitting existing concrete structures has led to many advances in the area of increasing the strength and stiffness of existing concrete members. Bonding steel and fiber reinforced plastic plates to the tension face of existing concrete members has evolved as a popular means with which to increase flexural strength and stiffness. These techniques often require substantial field preparation of the components and can result in significant construction cost. An alternative simple cost-effective method for increasing the flexural strength and serviceable stiffness of existing reinforced concrete members is presented. The proposed technique is based on fundamental principles of reinforced concrete design and involves the bolting of structural steel channels to the tension face of the existing concrete member. Validity of the method is established through experimental testing. Results indicate that the method provides an acceptable alternative to plate bonding to the tension soffit of existing concrete beams.