Free vibration analysis of plates resting on elastic foundations using modified Vlasov model

Ayvaz, Yusuf,Oguzhan, Celal Burak Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6

An application is presented of a modified Vlasov model to the free vibration analysis of plates resting on elastic foundations. The effects of the subsoil depth, the ratio of the plate dimensions, the ratio of the subsoil depth to the plate dimension in the longer direction, and the value of the vertical deformation parameter within the subsoil on the frequency parameters of plates on an elastic foundation are investigated. This analysis has been caried out by the aid of a computer program. The first ten frequency parameters are presented in tabular and the graphical forms to evaluate the effects of the parameters considered in this study. Then mode shapes corresponding to the first six of the frequency parameters are given in graphs. It is concluded that the effect of the subsoil depth on the frequency parameters of the plates on an elastic foundation is generally larger than those of the other parameters considered in this study.

Free vibration analysis of plates resting on elastic foundations using modified Vlasov model

Yusuf Ayvaz,Celal Burak O uzhan 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6

An application is presented of a modified Vlasov model to the free vibration analysis of plates resting on elastic foundations. The effects of the subsoil depth, the ratio of the plate dimensions, the ratio of the subsoil depth to the plate dimension in the longer direction, and the value of the vertical deformation parameter within the subsoil on the frequency parameters of plates on an elastic foundation are investigated. This analysis has been caried out by the aid of a computer program. The first ten frequency parameters are presented in tabular and the graphical forms to evaluate the effects of the parameters considered in this study. Then mode shapes corresponding to the first six of the frequency parameters are given in graphs. It is concluded that the effect of the subsoil depth on the frequency parameters of the plates on an elastic foundation is generally larger than those of the other parameters considered in this study.

Overall Cost Optimization of Prestressed Concrete Bridge using Genetic Algorithm

Zekeriya Aydın,Yusuf Ayvaz 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.4

Overall cost optimization of Prestressed Concrete (PC) bridges is investigated in this study. The purpose of this study is to determine the optimum span number and optimum cross-sectional properties of multi-span bridges. Considered bridge superstructure is constituted by adjacent simply supported pretensioned prestressed I-girders. Also, considered bridge substructure is constituted by single-column piers and rectangular spread footings. Span number, cross-section dimensions of prestressed girders and the area of Prestressing Steel (PS) are considered as design variables. PC girders, piers and footings are designed according to AASHTO Standard Specifications for Highway Bridges. A modified hybrid Genetic Algorithm (GA) is used for the optimum design. Working stress, ultimate strength, ductility limits, deflection, and geometry constraints are considered. Total cost of the bridge is taken as optimality criterion. A computer program is coded to perform optimum design and numerical examples from the application are designed. One of these examples is used in this paper. It is concluded that GA can be effectively used in the overall cost optimization of PC bridges.

Composed material models for nonlinear behavior of reinforced concrete

Tayfun Dede,Yusuf Ayvaz 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.12 No.3

The purpose of this study is to present different composed material models for reinforced concrete structures (RC). For this aim a nonlinear finite element analysis program is coded in MATLAB. This program contains several yield criteria and stress-strain relationships for compression and tension behavior of concrete. In this study, the well-known criteria, Drucker-Prager, von Mises, Mohr Coulomb, Tresca, and two new criteria, Hsieh-Ting-Chen and Bresler-Pister, are taken into account. It is concluded that the coded program, the new yield criteria, and the models considered can be effectively used in the nonlinear analysis of reinforced concrete beams.

Structural optimization with teaching-learning-based optimization algorithm

Dede, Tayfun,Ayvaz, Yusuf Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.4

In this paper, a new efficient optimization algorithm called Teaching-Learning-Based Optimization (TLBO) is used for the least weight design of trusses with continuous design variables. The TLBO algorithm is based on the effect of the influence of a teacher on the output of learners in a class. Several truss structures are analyzed to show the efficiency of the TLBO algorithm and the results are compared with those reported in the literature. It is concluded that the TLBO algorithm presented in this study can be effectively used in the weight minimization of truss structures.

Structural optimization with teaching-learning-based optimization algorithm

Tayfun Dede,Yusuf Ayvaz 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.4

In this paper, a new efficient optimization algorithm called Teaching–Learning-Based Optimization (TLBO) is used for the least weight design of trusses with continuous design variables. The TLBO algorithm is based on the effect of the influence of a teacher on the output of learners in a class. Several truss structures are analyzed to show the efficiency of the TLBO algorithm and the results are compared with those reported in the literature. It is concluded that the TLBO algorithm presented in this study can be effectively used in the weight minimization of truss structures.

Evaluation of rigid-end offset effect on seismic behavior of a structure subjected to Van earthquake

Serkan Bekiroğlu,Abdurrahman Şahin,Barış Sevim,Yusuf Ayvaz 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.6

Numerical damage assessment of Van train station building consisting of three RC blocks due to 2011 Van Earthquakes by nonlinear dynamic analysis is presented. The structural model is created with rigid-end offsets and plastic hinges for nonlinear analysis. Rigid-end offsets are considered for connection areas and proposed for wall-supported elements. In wall-supported elements, walls take place in a limited part of the columns. Nonlinear dynamic analysis of the building with and without rigid-end offsets is performed by using real earthquake records and results are compared. The results show that rigid-end offsets have significant effects on the seismic behavior of the structures.

Evaluation of rigid-end offset effect on seismic behavior of a structure subjected to Van earthquake

Bekiroglu, Serkan,Sahina, Abdurrahman,Sevima, Baris,Ayvaz, Yusuf Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.6

Numerical damage assessment of Van train station building consisting of three RC blocks due to 2011 Van Earthquakes by nonlinear dynamic analysis is presented. The structural model is created with rigid-end offsets and plastic hinges for nonlinear analysis. Rigid-end offsets are considered for connection areas and proposed for wall-supported elements. In wall-supported elements, walls take place in a limited part of the columns. Nonlinear dynamic analysis of the building with and without rigid-end offsets is performed by using real earthquake records and results are compared. The results show that rigid-end offsets have significant effects on the seismic behavior of the structures.

Assessment of damages on a RC building after a big fire

Ada, Mehmet,Sevim, Baris,Yuzer, Nabi,Ayvaz, Yusuf Techno-Press 2018 Advances in concrete construction Vol.6 No.2

This paper presents a case study about the damages on the structural elements of a cast in place reinforced concrete (RC) building after a big fire which was able to be controlled after six hours. The fire broke off at the $2^{nd}$ basement floor of the building, which has five basements, one ground, and two normal floors. As a result of intensely stocked ignitable materials, it spread out to the all of the upstairs. In visual inspection, most of the typical fire damages were observed (such as spalling, net-like cracks, crumbled plasters, bared or visible reinforcement). Also, failures of the $2^{nd}$ basement columns were encountered. It has been concluded that the severity failures of the columns at the $2^{nd}$ basement caused utterly deformation of the building, which is responsible for the massive damages on the beam-column connections. All of the observed damages were categorized related to the types and presented separated regarding the floors. Besides to the visual inspection, the numerical analysis was run to verify the observed damaged on the building for columns, beams, and the connection regions. It is concluded from the study that several parameters such as duration of the fire, level of the temperature influence on the damages to the RC building. Also, it is highlighted by the study that if the damaged building is considered on the overall structural system, it is not able to satisfy the minimum service requirements neither gravity loads nor earthquake conditions.