Aref A. Abadel

Textile-Reinforced Mortar versus FRP as Strengthening Material for Seismically Deficient RC Beam-Column Joints

In this paper, efficiency and effectiveness of textile-reinforced mortars (TRM) on upgrading the shear strength and ductility of a seismically deficient exterior beam-column joint has been studied. The results are then compared with that of carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP)-strengthened joint specimens. Five as-built joint specimens were constructed with nonoptimal design parameters (inadequate joint shear strength with no transverse reinforcement) representing an extreme case of preseismic code design construction practice of joints and encompassing the vast majority of existing beam-column connections. Out of these five as-built specimens, two specimens were used as baseline specimens (control specimens) and the other three were strengthened with TRM, CFRP, and GFRP sheets, respectively. All five subassemblages were subjected to quasi-static cyclic lateral load histories to provide the equivalent of severe earthquake damage. The response histories of control and strengthened specimens were then compared. The test results demonstrated that TRM can effectively improve both the shear strength and deformation capacity of seismically deficient beam-column joints to an extent that is comparable to the strength and ductility achieved by well-established CFRP, and GFRP-strengthening of joints.

Numerical Investigations on the Seismic Behavior of FRP and TRM Upgraded RC Exterior Beam-Column Joints

AbstractIn this paper, a detailed procedure for nonlinear finite-element analysis of fiber reinforced polymer (FRP) and textile reinforced mortar (TRM) upgraded reinforced concrete (RC) beam-column exterior joints is presented for predicting their seismic performance under simulated earthquake loading. The finite-element (FE) model was developed using a smeared cracking approach for concrete and three-dimensional layered elements for the FRP and TRM-composites. The results obtained from FE analysis were compared with the test results. The tests were conducted on four as-built exterior beam-column joint specimens under simulated seismic loads. Out of these four specimens, one specimen was tested as a control specimen and the other three were tested after strengthening with TRM, carbon FRP, and glass FRP sheets, respectively. The FE results were compared with the test results through load-displacement behavior, ultimate loads, and crack pattern. Comparison of FE results with the experimentally observed resp...

EFFECT OF CFRP AND TRM STRENGTHENING OF RC SLABS ON PUNCHING SHEAR STRENGTH

The paper presents experiments involving punching of RC slabs strengthened using externally bonded carbon fiber reinforced polymer (CFRP) sheet and textile reinforced mortar (TRM). Twelve RC slab specimens of two concrete grades (39.9 and 63.2 MPa) and employing two strengthening schemes (CFRP and TRM) were tested. Specimens were supported on two opposite edges. Experimental load-displacement variations show two peak loads in strengthened slabs and one peak followed by a plateau in control. Second peak or the plateau corresponds to the combined action of aggregate interlock and the dowel action of back face rebars and strengthening layers. The dowel action of back face rebars and strengthening layers had no role in ultimate punching load (i.e. first peak). Strengthened slabs showed 9-18% increase in ultimate punching load (i.e. first peak) whereas there was significant increase in the second peak load (190-276% for CFRP; 55-136% for TRM) and energy absorption (~66% for CFRP and 22-56% for TRM). An analytical model was also developed for predicting the punching shear strength (first and second peaks) of strengthened slabs showing good comparison with experiments.

Numerical Modeling of Steel Fiber-Reinforced Beam

Steel fibre reinforced concrete is emerging very popular and attractive material in structural engineering because of its enhanced mechanical performance as compared to conventional concrete. It is well established that one of the important properties of steel fibre reinforced concrete (SFRC) is its superior resistance to cracking and crack propagation. Additionally, incorporation of fibres in the concrete enhances the compressive, tensile and shear strengths, flexural toughness, durability and resistance to impact. The mechanical properties of fibre reinforced concrete depend on the type and specification of fibres. In this paper numerical investigation of SFRC beam using ANSYS is presented. The analysis was conducted till the ultimate failure cracks. Eight-noded solid brick elements were used to model the concrete. Internal reinforcement was modeled by using 3D spar elements. It has been observed the results from the finite element failure behavior indicates a good agreement with the experimental failure behavior.