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Wrapping technology is one of the effective ways of strengthening concrete elements. Several researchers reported the effectiveness of Glass fiber reinforced polymers and carbon fiber reinforced polymers for improving the strength of the concrete elements. Wrapping on three sides is one of the effective methods for strengthening the beams supporting slabs. Scant literature is available on the strength enhancement of ?U? wrapped concrete elements subjected to torsional loads. In this investigation an attempt is made to quantify the improvement in the behaviour of ?U? wrapped rectangular concrete members subjected to torsional loads ?U? wraps. Ferrocement is taken here as wrapping material. Beams were cast with different number of mesh layers with different torsional reinforcement. The beams were analyzed with MARS. The predictions are in good agreement with experimental test results.

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The inverse problem of evaluating mechanical properties of material from the observed values of load and deflection of a miniature disk bending specimen is discussed in this paper. It involves analysis of large amplitude, elasto-plastic deformation considering contact and friction. The approach in this work is to first generate—by a finite element (FE) solution—a large database of load-displacement (P-w) records for varying material properties. An artificial neural network (ANN) is trained with some of these data. The errors in the various values of the parameters during testing with additional known data were found to be reasonably small.

The post-cracking behaviour of structures subjected to torsion can be well predicted by Hsu's softened truss model. The softened truss model is applicable to structures having symmetry in their material properties on all four sides. Wrapping on three faces is a common phenomenon when the top face is provided with a flange or slab. Such a wrapping on three faces of a beam is referred to as a "U" wrap. "U" wraps are better wrapping strategies for distressed structures, as their top face is not accessible for many structures. The material property of an unwrapped face differs from the rest of wrapped faces. For the effective use of wrapping, the unwrapped face needs to be provided with a material having a higher resistance to tension and shear. For this, high-strength concrete in the core is a better option. Here, an attempt is made to predict the torsional capacity of "U" wrapped high-strength concrete beams having an asymmetry in the material using a softened truss model with suitable modifications of the material properties. Efficient algorithms are proposed for the solution of simultaneous equations. The predictions are found to be in good agreement with the experimental test results.

Wrapping is one of the effective ways of strengthening concrete elements. Several researchers have reported on the effectiveness of wrappings made from glass-fibre-reinforced polymers and carbon-fibre-reinforced polymers for improving the strength of concrete elements. Wrapping on three sides (‘U-wrapping’) is an effective method for enhancing the strength of beams supporting slabs, but scant literature is available on the strength enhancement of ‘U-wrapped’ concrete elements subjected to torsional loads. In the investigation reported in this paper, an attempt was made to quantify the improvement in the twist of U-wrapped rectangular concrete members subjected to torsional loads. Ferrocement was used as the wrapping material. Beams were cast with different amounts of reinforcement in the core and different wrapping portions, and the core concrete grade and wrapping mortar strength were also varied. The wrapped beams were analysed with the help of MARS software. An analytical model was subsequently developed to predict the secant stiffness at cracking torque (SSCT) using skew bending theory incorporating material properties. The model predictions for SSCT were found to be in good agreement with experimental test results.

The reactor channel of the horizontal core of pressurized heavy water reactors experiences very low sustained flow during loss of coolant accident (LOCA) at the reactor inlet feeders caused by certain breaks known as critical channel breaks. In this type of accident the reactor trip is delayed causing a gross mismatch of the heat generation and heat removal in the channel, thus leading to rapid temperature rise in the affected channel. A study has been carried out to identify the phenomena and the break size leading to such a situation. Severe fuel damage is predicted in the channel.

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