Indirect assessment of the contribution of NSM CFRP laminates for the shear str...

• Author(s): Barros, Joaquim A. O. ; Oliveira, Juliana T.
• Date: 2007
• Persistent ID: http://hdl.handle.net/1822/8485
• Origin: RepositóriUM - Universidade do Minho
• Subject(s): Near surface mounted; CFRP laminates; Shear strengthening; Debonding; Concrete; Critical crack
• Document Type: Conference Object
• Language: English

Description

Near Surface Mounted (NSM) strengthening technique has received increasing attention within the scientific and technical communities due to the positive indicators that this technique can provide in terms of strengthening performance. The NSM is especially effective for the shear strengthening of RC beams due to the ease of its application and the possibility of installing the Fibre Reinforced Polymer (FRP) elements in the most appropriate locations for the optimization of their contribution in terms of shear resistance. Furthermore, the FRP elements are protected against acts of vandalism and do not change the geometric configuration of the strengthened components since they are installed into thin slits opened on the concrete cover. Although either circular or rectangular FRP bars are used, recent research shows that the latter (herein designated as laminates) are more effective and easier to install. Research carried out in the area of NSM for the shear strengthening of RC beams reveals that the percentage, inclination and spacing of FRP laminates have a considerable influence on the effectiveness of this technique. The percentage of existent internal stirrups, the relative position of stirrups and FRP laminates and concrete strength class are also important aspects for the performance of the NSM technique. To estimate the influence of these parameters, a new test setup is proposed and an experimental program has been planned. The test setup is similar to the indirect tensile test (Brazilian test). The experimental program consists of 27 cylindrical concrete specimens of 180 mm thickness and 600 mm diameter, grouped in series for evaluating the influence of the aforementioned parameters. The test setup is detailed, and the results of the first series are presented and discussed.