Jacobs Journal of Civil Engineering

Seismic Evaluation of Framed Structures Reinforced by FRP bars

*Sara Mogahed
Department Of Structural Engineering, ZagaZig University, Egypt

*Corresponding Author:
Sara Mogahed
Department Of Structural Engineering, ZagaZig University, Egypt
Email:sara.mega-hed@zu.edu.eg

Published on: 2018-12-10

Abstract

The primary using FRP as replacement material instead of steel is curing corrosion in concrete structures, which caused damage in concrete. The use of FRP as concrete reinforcement is relatively new, despite of common using it as rehabilitation and retrofitting purpose. There are lacks of researches in, whether, experimentally or analytically data of performance and design of new FRP reinforced concrete structures, especially for seismically region. The main objectives of this research were evaluation the seismic performances of frames with FRP bars. Three models are considered to represent low-rise, medium-rise and high-rise frames. Also, this research is needed to gain a better understanding of the behavior of FRP materials and their interaction with traditional materials. A three parametric studied were investigated type of reinforcement, concrete strength and number of stories .In this study, analyzes of RC frames has been performed using SeismoStruct software. This is base shear - drift curve and the cracking behavior of performance criteria where obtained. By comparing the obtained results, it can be declared that FRP-RC frames are started to failure early than Steel-RC frames, thus the limit of inter-story drift at collapse prevention is different for FRP than Steel. Increasing number of stories affected on changing the stage of performance level of frames, however, the FRP-RC frame not much affect with this parameter. Increasing the concrete compressive strength enhanced the lateral load capacity for FRP-RC frames and with a little benefit for steel-RC frames. In general, the extent of damage experienced by the frames at the target displacement (performance point) was found to be between immediate occupancy and life safety when subjected to design lateral load.

Keywords

FRP; Reinforced concrete Frames; seismic evaluation; pushover analysis Inter-story drift; Performance level; SeismoStruct.

Introduction

Nonlinear static pushover analysis has become a popular analysis tool for seismic performance of reinforced concrete structures. Standards guidelines such as ATC 40 , FEMA 273 followed by FEMA 356 have given detailed guidelines to perform the nonlinear static pushover analysis and to use it to obtain the performance of the structures under a given lateral loads. To determine the performance of the structure against a given earthquake, are different for different method, FEMA 356 describing displacement coefficient method and FEMA 440 describing improvements to both capacity spectrum and displacement coefficient methods. In the last years , extensive research studied the behavior of FRP as strengthening material or as reinforcing for beams (exposed to flexural and shear loads), also a limited research work has been examined the axial behavior of RC columns with FRP, Afifi.M, et al[2]. carried an investigation on the circular column under monotonic axial load until failure, the specimens were reinforced with GFRP and steel bars and stirrups , The model takes into account the effect of many parameters such as; type of reinforcement, longitudinal reinforcement ratio; transverse reinforcement configuration; and the volumetric ratio. The results showed the compression failure of longitudinal FRP bars was by buckling or crushing, The amount and distribution of longitudinal FRP reinforcement significantly affected column ductility, with a slight strength gain.on the analytical side , S. Cimilli Erkmen and Saatcioglu [10] studied the behavior of a 5-storiey - 3-bay plane frame under seismic load and reinforced by FRP. Column and beams were confined with FRP Grid to ensure inelastic deformability, From analytical investigation CFRP reinforced concrete buildings can be used for seismically active regions. In Egyptian code ECP208 and ACI-440-1R-06, it isn’t recommend to use FRP in compression members or in seismic zones . FRP sections are designed according to ACI-440, ISIS.No3and CAN/CSA-S806-12. The objective of this study is to investigate the effect of FRP on the seismic behaviour of frame structures. Three RC frames with different heights representing low-, medium-, and high-rise structures, respectively, were designed and investigated frame. The pushover analysis was conducted based on SeismoStruct software to evaluate the seismic performance of the reinforced frames.