Panos Tsopelas - Academia.edu (original) (raw)

Papers by Panos Tsopelas

Journal of Structural Engineering, 2022

Materials and Structures, 2016

This paper presents a comprehensive experimental and numerical investigation on hysteretic behavi... more This paper presents a comprehensive experimental and numerical investigation on hysteretic behavior of thin-walled circular steel tubes as loaded members in reticulated shells. The experimental setup available for constant compression and biaxial bending loading was designed to examine the failure process, failure modes, load bearing capacity, ductility, stiffness degradation and energy dissipation capacity of sixteen thin-walled circular steel tubes. Also, the effects of the loading condition, axial load ratio, slenderness and steel strength on hysteretic behavior of specimens were investigated. The study showed that test results of specimen loaded in two directions might overestimate hysteretic characteristic of this member. Premature local buckling may be caused by the high axial load ratio and the recommended axial load ratio may be n B 0.2 to ensure the load bearing capacity, deformation capacity and ductility of circular steel tubes and to prevent the premature local buckling occurring in engineering practice. Slenderness affects the load bearing capacity, ductility, and energy dissipation capacity of specimens, and with an increasing slenderness, the stiffness degraded considerably and quickly. Specimens with high strength steel exhibited higher load bearing capacity and better stiffness but lower energy dissipation capacity than those made by low strength steel. Furthermore, the nonlinear finite element analysis was performed to simulate hysteretic behavior of test specimens, and the results got a satisfactory agreement with those of test.

2007 Annual Conference & Exposition Proceedings

His research interests include network scheduling, construction operations simulation and optimiz... more His research interests include network scheduling, construction operations simulation and optimization, equipment economics, constructability analysis, and innovative teaching methods. He has studied statistical equipment valuation models and has participated in research

In this paper, the underlying energy flow in rocking dynamics of rigid blocks is utilized to eluc... more In this paper, the underlying energy flow in rocking dynamics of rigid blocks is utilized to elucidate their response details and overturning conditions. Based merely on the law of the conservation of energy, the exact criteria for a rigid block to overturn in the free vibration regime are established for the first time in the context of both nonlinear and linear theory. That is, if the initial conditions of the free oscillation regime fall within the prescribed stable libration region, then it is a priori determined that the block will not overturn and vice versa. The analytical solution to the nonlinear free rocking problem is also derived, utilizing integration techniques originating from the solution of the nonlinear pendulum. Additionally, pulse-type overturning spectra are constructed easily by numerical integration of the equation of motion only during the pulse duration. If the block does not topple during the forced regime, the angle and angular velocity at the end of the e...

In 1991, the University at Buffalo and Taisei Corporation began a collaborative research program ... more In 1991, the University at Buffalo and Taisei Corporation began a collaborative research program on the experimental study of advanced sliding seismic isolation systems for bridges. The project had the objectives of producing and experimentally verifying a class of sliding isolation systems by modifying and/or adapting existing technology. Particular emphasis was given to the adaptation and use of aerospace and military hardware. Furthermore, the project included the study of established sliding isolation systems such as the Friction Pendulum (or FPS) system which has been used in a number of buildings and other, but not bridge, applications, and the lubricated sliding bearing/yielding steel damper system used in a large number of bridges in Italy. This paper describes the experimental program and representative results.

Friction Pendulum bearings have been extensively tested for different environmental conditions an... more Friction Pendulum bearings have been extensively tested for different environmental conditions and loadings applicable to bridges. Data are presented from various test programs, spanning six years, and including several hundred shake table and compression-shear tests. Shake table tests of bridge models were used to verify dynamic performance of the seismic isloation system. Results are reported for models of bridge decks mounted on flexible piers and rigid abutment supports, and for various types of ground motions, including standard Caltrans ground motion spectra and near fault pulse motions. Comparisons between experimental results and dynamic analysis results are presented. Compression-shear test results are reported for the effects of temperature from minus 20 degrees F to 90 degrees F, 20,000 cycles of thermal movements, simulated aging, scragging, compression overloads, and tension loads. The test results show the effect of these factors on the properties of the bearing. Resul...

Proceedings of the Ninth International Conference on Civil and Structural Engineering Computing, 2003

Journal of Structural Engineering, 1997

Seismic isolation bearings consisting of lubricated sliding bearings and steel dampers exhibit ne... more Seismic isolation bearings consisting of lubricated sliding bearings and steel dampers exhibit nearly elastoplastic behavior. Accordingly, they can transfer force to bridge substructures that are independent of the level and frequency content of seismic excitation. While this is a ...

Earthquake Engineering & Structural Dynamics, 1996

York and Taisei Corporation nor any person acting on their behalf: a. makes any warranty, express... more York and Taisei Corporation nor any person acting on their behalf: a. makes any warranty, express or implied, with respect to the use of any information, apparatus, method, or process disclosed in this report or that such use may not infringe upon privately owned rights; or b. assumes any liabilities of whatsoever kind with respect to the use of, or the damage resulting from the use of, any information, apparatus, method, or process disclosed in this report.

In: Lee, George C., ed; Friedland, Ian M., ed. Post - Earthquake reconstruction strategies : NCEE... more In: Lee, George C., ed; Friedland, Ian M., ed. Post - Earthquake reconstruction strategies : NCEER - INCEDE center - to - center project. Buffalo, NY, US Nacional Center for Earthquake Engineering Research (NCEER);Japan International Center for Disaster Mitigation ...

... DAMPERS IN APPLICATIONS OF SEISMIC ENERGY DISSIPATION AND SEISMIC ISOLATION by MC Constantino... more ... DAMPERS IN APPLICATIONS OF SEISMIC ENERGY DISSIPATION AND SEISMIC ISOLATION by MC Constantinou, MD Symans ... FLUID VISCOUS DAMPERS IN APPLICATIONS OF SEISMIC ENERGY DISSIPATION AND SEISMIC ISOLATION MC Constantino«!, MD Symans, P ...

Journal of Structural Engineering, 2022

Materials and Structures, 2016

This paper presents a comprehensive experimental and numerical investigation on hysteretic behavi... more This paper presents a comprehensive experimental and numerical investigation on hysteretic behavior of thin-walled circular steel tubes as loaded members in reticulated shells. The experimental setup available for constant compression and biaxial bending loading was designed to examine the failure process, failure modes, load bearing capacity, ductility, stiffness degradation and energy dissipation capacity of sixteen thin-walled circular steel tubes. Also, the effects of the loading condition, axial load ratio, slenderness and steel strength on hysteretic behavior of specimens were investigated. The study showed that test results of specimen loaded in two directions might overestimate hysteretic characteristic of this member. Premature local buckling may be caused by the high axial load ratio and the recommended axial load ratio may be n B 0.2 to ensure the load bearing capacity, deformation capacity and ductility of circular steel tubes and to prevent the premature local buckling occurring in engineering practice. Slenderness affects the load bearing capacity, ductility, and energy dissipation capacity of specimens, and with an increasing slenderness, the stiffness degraded considerably and quickly. Specimens with high strength steel exhibited higher load bearing capacity and better stiffness but lower energy dissipation capacity than those made by low strength steel. Furthermore, the nonlinear finite element analysis was performed to simulate hysteretic behavior of test specimens, and the results got a satisfactory agreement with those of test.

2007 Annual Conference & Exposition Proceedings

His research interests include network scheduling, construction operations simulation and optimiz... more His research interests include network scheduling, construction operations simulation and optimization, equipment economics, constructability analysis, and innovative teaching methods. He has studied statistical equipment valuation models and has participated in research

In this paper, the underlying energy flow in rocking dynamics of rigid blocks is utilized to eluc... more In this paper, the underlying energy flow in rocking dynamics of rigid blocks is utilized to elucidate their response details and overturning conditions. Based merely on the law of the conservation of energy, the exact criteria for a rigid block to overturn in the free vibration regime are established for the first time in the context of both nonlinear and linear theory. That is, if the initial conditions of the free oscillation regime fall within the prescribed stable libration region, then it is a priori determined that the block will not overturn and vice versa. The analytical solution to the nonlinear free rocking problem is also derived, utilizing integration techniques originating from the solution of the nonlinear pendulum. Additionally, pulse-type overturning spectra are constructed easily by numerical integration of the equation of motion only during the pulse duration. If the block does not topple during the forced regime, the angle and angular velocity at the end of the e...

In 1991, the University at Buffalo and Taisei Corporation began a collaborative research program ... more In 1991, the University at Buffalo and Taisei Corporation began a collaborative research program on the experimental study of advanced sliding seismic isolation systems for bridges. The project had the objectives of producing and experimentally verifying a class of sliding isolation systems by modifying and/or adapting existing technology. Particular emphasis was given to the adaptation and use of aerospace and military hardware. Furthermore, the project included the study of established sliding isolation systems such as the Friction Pendulum (or FPS) system which has been used in a number of buildings and other, but not bridge, applications, and the lubricated sliding bearing/yielding steel damper system used in a large number of bridges in Italy. This paper describes the experimental program and representative results.

Friction Pendulum bearings have been extensively tested for different environmental conditions an... more Friction Pendulum bearings have been extensively tested for different environmental conditions and loadings applicable to bridges. Data are presented from various test programs, spanning six years, and including several hundred shake table and compression-shear tests. Shake table tests of bridge models were used to verify dynamic performance of the seismic isloation system. Results are reported for models of bridge decks mounted on flexible piers and rigid abutment supports, and for various types of ground motions, including standard Caltrans ground motion spectra and near fault pulse motions. Comparisons between experimental results and dynamic analysis results are presented. Compression-shear test results are reported for the effects of temperature from minus 20 degrees F to 90 degrees F, 20,000 cycles of thermal movements, simulated aging, scragging, compression overloads, and tension loads. The test results show the effect of these factors on the properties of the bearing. Resul...

Proceedings of the Ninth International Conference on Civil and Structural Engineering Computing, 2003

Journal of Structural Engineering, 1997

Seismic isolation bearings consisting of lubricated sliding bearings and steel dampers exhibit ne... more Seismic isolation bearings consisting of lubricated sliding bearings and steel dampers exhibit nearly elastoplastic behavior. Accordingly, they can transfer force to bridge substructures that are independent of the level and frequency content of seismic excitation. While this is a ...

Earthquake Engineering & Structural Dynamics, 1996

York and Taisei Corporation nor any person acting on their behalf: a. makes any warranty, express... more York and Taisei Corporation nor any person acting on their behalf: a. makes any warranty, express or implied, with respect to the use of any information, apparatus, method, or process disclosed in this report or that such use may not infringe upon privately owned rights; or b. assumes any liabilities of whatsoever kind with respect to the use of, or the damage resulting from the use of, any information, apparatus, method, or process disclosed in this report.

In: Lee, George C., ed; Friedland, Ian M., ed. Post - Earthquake reconstruction strategies : NCEE... more In: Lee, George C., ed; Friedland, Ian M., ed. Post - Earthquake reconstruction strategies : NCEER - INCEDE center - to - center project. Buffalo, NY, US Nacional Center for Earthquake Engineering Research (NCEER);Japan International Center for Disaster Mitigation ...

... DAMPERS IN APPLICATIONS OF SEISMIC ENERGY DISSIPATION AND SEISMIC ISOLATION by MC Constantino... more ... DAMPERS IN APPLICATIONS OF SEISMIC ENERGY DISSIPATION AND SEISMIC ISOLATION by MC Constantinou, MD Symans ... FLUID VISCOUS DAMPERS IN APPLICATIONS OF SEISMIC ENERGY DISSIPATION AND SEISMIC ISOLATION MC Constantino«!, MD Symans, P ...