دانلود رایگان مقاله انگلیسی رفتار لرزه ای قاب های بتن مسلح صفحه ای با قاعده با بتن تقویت شده با الیاف در اتصالات - اشپرینگر 2018

Abstract

According to most of current design standards, the need for high strength and ductility of reinforced concrete frame structures is accomplished utilizing a high amount of transverse reinforcement in beam–column joints. Reinforcement congestion can be overcome by means of Fiber Reinforced Concrete and High Performance Fiber Reinforced Concrete, which are known to improve the structural performance of single structural members or beam–column joints. Through an extended numerical simulation, this paper elaborates the overall benefits of using fiber reinforced concrete materials in critical regions to the seismic behaviour of regular reinforced concrete frame structures. An extensive number of non-linear static and dynamic analyses with distributed plasticity and fibre sections are performed to compare the behaviour of simple reinforced concrete and mixed reinforced concrete/fiber reinforced concrete frames in terms of total base shear and fragility curves and failure mechanisms. Even if execution and technological aspects are beyond the scope of the present work, the use of fiber reinforced concretes in critical regions of mixed frames seems to improve the structural performance of reinforced concrete frames at a global level.

7 Conclusions

The study of the mechanical performance of RC/FRC frames is one of the topics at the forefront of today’s research activities in the structural domain, which is mainly devoted to experimental behaviour of columns, beam–column joints and frames subjected to cyclic actions. Beyond any doubt, the performance of FRC members, even devoid of transverse reinforcement, positively affects tensile, shear and bending behaviours.

The purpose of this work is to investigate the use of fibre-reinforced materials in the critical regions of concrete frames subjected to seismic loads, where a high dissipation ability is required. A numerical investigation focused on the global behaviour of earthquake-resistant RC plane frames with FRC materials in the joint regions was presented and discussed. Static and dynamic non-linear analyses were performed, based on a diffused plasticity model with fibre sections. Investigations on a number of variables such as frame geometry, FRC/RC material grade combinations, lateral load profile, joint modelling technique and floor in-plane constraint are carried out. Frames with FRC in joints prove to have better performances than reference RC frames. In fact, in FRC frames the total base shear capacity is higher than in reference frames, while the behaviour factor is not affected as much and the collapse probability is increased. Therefore, for a given geometry, adopting fibre-reinforced materials in the joints brings in not only a higher lateral stiffness, but also a higher global capacity, leading to reduced lateral displacements in case of nondestructive earthquakes (Serviceability Limit State).