INTERNATIONAL JOURNAL OF ADVANCED STRUCTURAL ENGINEERING
Year:2013 | Volume:5 | Issue:-|Papers Count:2

The present investigation addresses the shear strengthening of deficient reinforced concrete (RC) beams using carbon fiber-reinforced polymer (CFRP) sheets. The effect of the pattern and orientation of the strengthening fabric on the shear capacity of the strengthened beams were examined. Three beams with various lay-ups of strengthening fabric, 45o, 0o/90o, and 0o/90o/45o were examined, in addition to an unstrengthened control beam. Principal and shear strains were measured at different locations at the critical sections of the strengthened beams corresponding to each applied shear force. Experimental results showing the advantage of beam strengthened using the various lay-ups of CFRP sheets are discussed. It is concluded that Beam-45o, Beam-0o/90o, and Beam-0o/90o/45o show about 25%, 19%, and 40% increases in shear-load carrying capacity in comparison to the control beam, respectively. Also, there exists a critical value of shear force up to which there is no appreciable shear strain in the CFRP sheets/beam. This shear force marks the ultimate shear resistance of the control beam. However, the strengthened beams exhibited significant strength and stiffness even beyond the critical value of the shear force. A design example for shear strengthening shows that the design equations available in the literature underestimate the actual shear strength of the beams.

Infilled walls are normally considered as nonstructural elements. However, these walls are effective in carrying lateral loads. In this regard, an experimental investigation was planned and conducted to study the effect of braced and partially concrete-infilled, reinforced concrete (RC) frames in comparison to the bare frames. All these frames were tested up to collapse and subjected to only horizontal loads to obtain an effective and possible solution for soft story. In comparison to bare RC frames, partially infilled frames have more lateral load capacity. Central bracing is more effective than that of corner bracing. For the same load, braced and partially infilled frames deflected significantly less than that of the bare frames. Based on experimental observations, a mathematical model has been proposed to calculate theoretical ultimate load for braced and partially infilled RC frames.