Civil Engineering / İnşaat Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/13

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Author: search.filters.author.Turan, GürsoyScopus Q: search.filters.scopusQuartile.Q1

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Now showing 1 - 6 of 6
  • Article
    Citation - WoS: 11
    Citation - Scopus: 12
    An Improved Passive Tuned Mass Damper Assisted by Dual Stiffness
    (Elsevier, 2023) Roozbahan, Mostafa; Turan, Gürsoy
    A tuned mass damper (TMD) is one of the oldest and most commonly used passive control devices attached to structures to absorb lateral loads of energy from main systems. In the last decades, several novel tuned mass dampers have been designed to increase the performance of TMDs in decreasing the structural responses during excitation vibrations. Moreover, several formulations and numerical optimization methods have been developed to optimize the TMDs parameters. This paper proposes a novel passive tuned mass damper with dual stiffness (DSTMD). The DSTMD includes mass, primary and secondary springs, dashpot, and motion limiting chamber. The performance of DSTMDs depends on their properties such as mass, primary and secondary stiffness, damping coefficient, and the length of the motion limiting chamber. Thus, a metaheuristic optimization algorithm, called the Mouth Brooding Fish algorithm, was used to optimize the DSTMDs parameters. The effectiveness of the optimum DSTMD on two different linear ten-story structures under several earthquakes has been studied and compared with the effectiveness of classical optimum TMDs. According to the study, optimum DSTMDs generally show better effects for certain excitations, and as an average performance, they are superior compared to the classical optimum TMDs in reducing maximum displacement of the buildings. At last, structural yielding is considered, and the performance analysis on this structure shows that the DSTMD has a superior effect in reducing the maximum displacement and is among the best methods for the calculated absolute yielding amount.
  • Article
    Citation - WoS: 15
    Citation - Scopus: 16
    A Mode Shape Assembly Algorithm by Using Two Stage Bayesian Fast Fourier Transform Approach
    (Academic Press Inc., 2019) Hızal, Çağlayan; Turan, Gürsoy; Aktaş, Engin; Ceylan, Hasan
    Operational modal analysis may require identifying global modal shapes by using multiple setup measurements. For this purpose, various algorithms have been developed which make use of the Bayesian approach to estimate the global mode shapes. The main motivation of the available Bayesian approaches is based on the estimation of the optimal global mode shape vector directly from Fast Fourier Transform data or assembling the local mode shapes that are identified in the individual setups by using Gaussian approximation. In this study, the two-stage Bayesian Fast Fourier Transform Approach which is originally applied to single setups is implemented to multiple setup problems for well separated modes. Analytically it is shown that the resulting formulation is the same for the mode shape assembly by using the Gaussian approximation. In addition, the weights of individual setups in the global mode shape vector is analytically calculated which depend on the Hessian matrix for local mode shapes. To validate the proposed methodology, a numerical example that considers setup-to-setup variability of modal signal-noise ratios is presented. For comparison purposes a ten-story shear frame model is experimentally investigated, and the measurements of a benchmark bridge structure are considered in the verification of the current procedure. (C) 2019 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 29
    Citation - Scopus: 29
    A Two-Stage Bayesian Algorithm for Finite Element Model Updating by Using Ambient Response Data From Multiple Measurement Setups
    (Academic Press, 2020) Hızal, Çağlayan; Turan, Gürsoy
    This study presents a two-stage Bayesian finite element model updating procedure by using acceleration response measurements obtained from multiple setups. In the presented methodology, parametric uncertainties for the modal parameters are estimated by using the Bayesian Fast Fourier Transform Approach (BFFTA). Different from the previous Bayesian methods, a block diagonal covariance matrix is modeled for prior estimation of measured modal parameters. In addition, the modelling error in the eigenvalue equations is considered as soft constraints to be updated. Numerical and experimental studies are presented to validate the proposed method. The effect of soft constraints on the identification results as well as their posterior uncertainties are investigated. According to the results, it is shown that the proposed methodology can identify the most probable finite element model parameters with high level of accuracy. In addition, the posterior uncertainties obtained by the proposed procedure are significantly small when compared to the methods that consider rigid constraints for prediction and/or modelling error. (C) 2019 Elsevier Ltd. All rights reserved.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Effect of Seismic Wave Velocity on the Dynamic Response of Multi-Story Structures on Elastic Foundation
    (Elsevier Ltd., 2018) Hızal, Çağlayan; Turan, Gürsoy
    Traveling wave effects are generally considered with three main cases: (i) Wave passage effect that results with time delay in earthquake motion. (ii) incoherence effect which is defined as loss of coherency in the ground motion due to the reflection and refraction of waves, and (iii) local site effects. For multi-story structures whose supports are close to each other, the incoherence and local site effect may be omitted. In this case, traveling waves result only in a pure time delay in the earthquake motion (wave passage effect). Due to the wave passage effect of vertical and/or horizontal ground motion, the superstructure needs to be analyzed by multi-support excitation. Raft foundations cannot constrain vertical deformations and/or rotations, but they cause a diaphragm effect in the horizontal direction which results in uniform excitation. In this study, the effect of vertical earthquake motions onto multi-story buildings on elastic soil is investigated. Multi support excitation is considered by using displacement loading, which defines the equivalent seismic loads in terms of the ground displacement. According to the performed simulations of the selected structures, it is shown that structural height has a direct influence that results in member force magnifications with slow traveling wave effect. Among these, the ground floor column axial forces are most affected.
  • Article
    Citation - WoS: 4
    Citation - Scopus: 5
    Importance of Static Correction and Damping in the Analysis of a Cable-Stayed Bridge Subjected To Displacement Loading
    (American Society of Civil Engineers (ASCE), 2017) Hızal, Çağlayan; Turan, Gürsoy
    Cable-stayed bridges with long spans are excited by different support vibrations on both sides of the main span. Therefore, a realistic seismic structural analysis of the bridge must involve multiple-support excitation. The dynamic equation of motion, in which all degrees of freedom are solved at once, can be solved directly. A modal analysis might also be possible, but care must be taken with the number of modes used in the analysis. If the ground motion is described in terms of displacement and velocity, which is referred to as displacement loading, then a static correction that will account for the unconsidered higher modes must be performed. In this study, the procedure of multiple-support excitation through the use of modal transformation is explained in detail. The effects of changes in damping levels that affect the analysis results are investigated by using the static correction method in displacement loading. An example is given to illustrate the mentioned problem by using a finite-element model of the cable-stayed Bill Emerson Memorial Bridge.
  • Article
    Citation - WoS: 132
    Citation - Scopus: 183
    Phase I Benchmark Control Problem for Seismic Response of Cable-Stayed Bridges
    (American Society of Civil Engineers (ASCE), 2003) Dyke, Shirley J.; Caicedo, Juan Martin; Turan, Gürsoy; Bergman, Lawrence A.; Hague, Steven T.
    This paper presents the problem definition for the first generation of benchmark structural control problems for cable-stayed bridges. The benchmark problem is based on the Bill Emerson Memorial Bridge that is currently under construction in Cape Girardeau, Missouri. Construction of the bridge is expected to be completed in 2003. The goal of this study is to provide a testbed for the development of strategies for the control of cable-stayed bridges. Based on detailed drawings, a three-dimensional evaluation model has been developed to represent the complex behavior of the full scale benchmark bridge. The linear evaluation model is developed using the equations of motion generated around the deformed equilibrium position. Evaluation criteria are selected that are consistent with the goals of seismic response control of a cable-stayed bridge. Control constraints ensure that the results are representative of a control implementation on the physical structure. Each participant in this benchmark study is given the task of defining (including devices, sensors, and algorithms), evaluating, and reporting on their proposed control strategies. These strategies may be either passive, active, semiactive, or a combination thereof. A simulation program is provided to facilitate direct comparison of the capabilities and efficiency of the various control strategies. The problem is available through the internet in the form of a set of MATLAB programs and includes a sample control design to guide participants through the benchmark problem.