INTERNATIONAL JOURNAL OF ADVANCED STRUCTURAL ENGINEERING
Year:2014 | Volume:6 | Issue:-|Papers Count:3

The present paper deals with experimental and finite element studies carried out on free vibration of isotropic and laminated composite cylindrical skew panels. Natural frequencies were determined using CQUAD8 finite element of MSC Nastran, and comparison was made between the experimental values and the finite element solution. Effects of the skew angle and aspect ratio on the natural frequencies of isotropic cylindrical skew panels were studied. The effects of skew angle, aspect ratio, fiber orientation angle, and laminate stacking sequence (keeping total number of layers in the laminate constant) on the natural frequencies of antisymmetric laminated composite cylindrical skew panels were also studied. The experimental values of the first, second, and third natural frequencies are in good agreement with the finite element solution for both isotropic and laminated composite cylindrical panels. The first, second, and third natural frequencies are found to decrease with the increase in the aspect ratio for both isotropic and laminated composite cylindrical panels.

Due to earthquake, buildings are damaged partially or completely. Particularly, structures with soft storey are mostly affected. In general, such damaged structures are repaired and reused. In this regard, an experimental investigation was planned and conducted on models of single bay, single storey of partial concrete infilled reinforced concrete (RC) frames up to collapse with corner, central, and diagonal steel bracings. Such collapsed frames were repaired with epoxy resin and retested. The initiative was to identify the behavior, extent of restored ultimate strength, and deflection of epoxy-retrofitted frames in comparison with the braced RC frames. The performance of such frames has been considered only for lateral loads. In comparison with bare RC frames, epoxy-repaired partial infilled frames have significant increase in lateral load capacity. Central bracing is more effective than corner and diagonal bracing. For the same load, epoxy-repaired frames have comparable deflection than similar braced frames.

This paper presents an analytical model to calibrate the tension stiffening effect of tensile reinforced concrete members. The tension stiffening behaviour is a primordial task in reinforced concrete mechanic field. In this model, the stress–strain relationship of the tension stiffening effect described in the cracking range is proposed. The application of the analytical expression for tensile reinforced concrete member aims principally to quantify the tension stiffening phenomenon in the cracking range. In this concern, a parametrical study is established, which concerns the influence of concrete strength, reinforcement ratio, bar diameter and instantaneous properties of concrete on the tension stiffening behaviour. The obtained results relative to the influence of different parameters of the analysis are shown and commented.