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This paper aims to model the performances of frames structures by comparing the predictions of ordinary control concrete (CC) and concretes reinforced by fibers. Two types of steel fibers were used in this work, industrial steel fibers (ISF) and tire-reclaimed fibers obtained by cutting virgin steel tire-cord to 50 mm, noticed virgin steel fibers (VSF). In total, 3% of VSF are used. The results obtained in this paper clearly show the contribution of fibers in improving the global and local behavior of the frames structures. VSF gives the same or better overall behavior as the use of industrial fibers for the same percentage of fibers, with the advantage that VSF contributes to the protection of the environment and limit the wastage of steel.

This work was carried out using the commercial finite element code Abaqus/Explicit. The behavior of the different concretes used in this study was modeled by the concrete damage plasticity (CDP) constitutive law. The methodology adopted to complete this work consisted in identifying, by calibration of the available experimental results with the numerical predictions, the parameters of the corresponding CDP model for each of the concretes used in this work. To this end, the authors have successively identified the CDP parameters for the CC-V (control concrete used by Vecchio and Emara, 1992) used in frame structure (R + 1). Subsequently, the CDP parameters of the CC-T (control concrete used by Tlemat, 2004), the CVSF (concrete with virgin steel fibers) and the CISF-1 (concrete with industrial steel fibers type 1, ISF-1) are identified using the experimental results of beams under bending tests. Once the model parameters were determined for each concrete, the authors conducted a series of simulations to show the benefit of introducing claimed and industrial fibers in frame structure (R + 1) and (R + 2). This approach recommends the use of concrete reinforced with steel fibers, mainly 6% by mass of VSF and ISF-1, in place of ordinary concrete in new construction to increase the resistance of structures and contribute, if applicable, to the protection of the environment.

The main findings of this study can be summarized by: the strength and ductility of the frames structures made of concrete fiber are significantly increased. The use of tire-reclaimed steel fibers (VSF) gives the same or better overall behavior as the use of industrial fibers. In addition to their good mechanical contribution, the tire-reclaimed fibers contribute to the protection of the environment and limit the wastage of steel. The use of fibers reduces the cracking zones in concrete fiber frames structures. The usefulness of distinguishing the interstory displacement limits set by codes, in particular, uniform building code (UBC-97), for ordinary concretes and concrete reinforced with fibers is addressed.

The contribution of tire-reclaimed and industrial fibers on the strength and ductility of reinforced concrete-frames structures is addressed. The use of tire-reclaimed steel fibers gives the same or better overall behavior as the use of industrial fibers, the tire-reclaimed fibers having the advantage of contributing to the protection of the environment and limiting the wastage of steel. The paper also points to the usefulness of distinguishing the interstory displacement limits set by codes, in particular UBC-97, for ordinary concrete and concrete reinforced with fibers, in accordance to the predictions of the capacity curves.

The purpose of this study is to establish a relationship between causes and effects, the respect of materials characteristics values [concrete compressive strength (f_c) and steel yield stress (f_y)] and the norms of the construction dispositions value (covers). This study is motivated by the post-seismic damages related to the plastification of the reinforced concrete (RC)/beams sections, named plastic hinges. The results are given by fragility curves representing the failure probability (P_f) of the plastic hinges versus covers value.

A mechanical-reliability coupling methodology is proposed and performed on three frames (three, six and nine storey). For each frame, seven covers the value of reinforcement steel bars has been taken into account in the beams. After definition of the limit state function G(x), a process of idea to twin-track; deterministic and probabilistic, is considered. Thus, numerical simulations are carried out under ETABS© software, to extract a soliciting moments M_s(x). Then, ultimate moments M_u(x), the result of reliability approach are calculated using Monte Carlo Simulations. In this step, two random variables; concrete compressive strength in 28 days of age (f_c) and steel yield stress (f_y), have been studied.

In the mechanical study, the results show that, the first plastic hinge appears at the beams for all frames. In the reliability study, the (f_y) variation shows that all plastic hinges are in failure domain, nevertheless, the (f_c) variation leads to have all sections in the safety domain, except A7 and B7 models. The failure probability (P_f) calculation according to (f_c) and (f_y) shows that an absolute error of 0.5 cm in the steel bars covers can switch the frame from the safety domain to the failure domain.

The plastic hinges reliability of the RC/ frame structures is independent on the high of the structure. The (f_c) random variable according to the used distribution law does not affect the reliability (safety or failure). However, the impact of the steel yield stress variation (f_y) is not negligible. The errors in covers affect considerably the strength of the elements.