Current Issue : April - June Volume : 2017 Issue Number : 2 Articles : 5 Articles
The purpose of this study was to evaluate the flexural performance of recycled aggregate RC beam reinforced with aramid fiber\nsheets. Compressive strength of concrete using recycled aggregate is generally similar or slightly lower than normal concrete. To\nimprove the compressive strength, aramid fiber sheets have been used in this study. This study examines the structural behavior\nof concrete beams prepared with recycled aggregate and strengthened aramid fiber sheets at varying locations. One concrete beam\nas a control specimen, that is prepared with 30 percent recycled aggregate and 70 percent natural aggregate, has been tested, and\n3 more strengthened beams (bottom, bottom and sides, bottom and both ends with U-shaped strengthened beams) are tested.\nThe ultimate loads have increased by 38.01%, 39.88%, and 100.79% for bottom, bottom and sides, bottom and both ends with Ushaped\nstrengthened beams.The ductility ratios are 2.75âË?¼6.20 for strengthened beams. The experimental results showed that the\nstrengthening system with U-shaped band controls the premature debonding and provides a more ductile failure mode than the\nstrengthening system without U-shaped bands. It can be found that the ultimate strength of H40-RGA30-BS specimen based on\nload-deflection curves shows most promising result.The experimental results are compared with the analytical results of nonlinear\nflexural behaviors for strengthened reinforced recycled aggregate concrete beam....
The present study investigates the prediction efficiency of nonlinear system-identification\nmodels, in assessing the behavior of a coupled structure-passive vibration controller. Two\nsystem-identification models, including Nonlinear AutoRegresive with eXogenous inputs (NARX)\nand adaptive neuro-fuzzy inference system (ANFIS), are used to model the behavior of an\nexperimentally scaled three-story building incorporated with a tuned mass damper (TMD) subjected\nto seismic loads. The experimental study is performed to generate the input and output data sets\nfor training and testing the designed models. The parameters of root-mean-squared error, mean\nabsolute error and determination coefficient statistics are used to compare the performance of the\naforementioned models. A TMD controller system works efficiently to mitigate the structural\nvibration. The results revealed that the NARX and ANFIS models could be used to identify the\nresponse of a controlled structure. The parameters of both two time-delays of the structure response\nand the seismic load were proven to be effective tools in identifying the performance of the models.\nA comparison based on the parametric evaluation of the two methods showed that the NARX model\noutperforms the ANFIS model in identifying structures response....
Degradation of RC structures due to chloride penetration followed by reinforcement corrosion is a serious problem in civil\nengineering. The numerical simulation methods at present mainly involve finite element methods (FEM), which are based on\nmesh generation. In this study, element-free Galerkin (EFG) and meshless weighted least squares (MWLS) methods are used to\nsolve the problem of simulation of chloride diffusion in concrete. The range of a scaling parameter is presented using numerical\nexamples based on meshless methods. One- and two-dimensional numerical examples validated the effectiveness and accuracy of\nthe two meshless methods by comparing results obtained by MWLS with results computed by EFG and FEM and results calculated\nby an analytical method. A good agreement is obtained among MWLS and EFG numerical simulations and the experimental data\nobtained from an existing marine concrete structure. These results indicate that MWLS and EFG are reliable meshless methods\nthat can be used for the prediction of chloride ingress in concrete structures....
In this study, tapered polymer fiber sensors (TPFSs) have been employed to detect the\nvibration of a reinforced concrete beam (RC beam). The sensing principle was based on transmission\nmodes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were\ncarried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection\nresults agreed well with Kistler accelerometers. The experimental results found that both the\naccelerometer and TPFS detected the natural frequency function of a vibrated RC beam well.\nThe mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration\ndetection method provides a cost-comparable solution for a structural health monitoring (SHM)\nsystem in civil engineering....
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