Research work in the area of Structural Engineering is concentrated on risk mitigation and urban resilience. Current research activities address modelling and design of structures subjected to extreme loads, structural health monitoring, structural fire safety, and seismic risk reduction.
Modelling and design of structures subjected to extreme loads
With the introduction of performance-based methodologies for design and evaluation of structures, analytical modeling of their behavior under extreme loads such as earthquake and blast induced excitations has recently gained substantial importance among researchers. A reliable prediction of the nonlinear inelastic response of structural systems inherently requires the use of analytical models that can accurately capture the hysteretic behavior of the individual members, as well as their interaction, under generalized loading conditions.
Dr. Kutay Orakçal works actively on development of phenomenological (behavioral) models to simulate the seismic response characteristics of reinforced concrete members – structural walls in particular. To date, he has contributed to development of i) a macroscopic fiber model to represent the nonlinear flexural response of structural walls, ii) a fiber-based bond-slip model to characterize the response of columns and walls with inadequate lap splices, iii) various fiber-based shear-flexure interaction model formulations to capture coupled nonlinear shear and flexural responses in walls, columns, and coupling beams, iv) a generalized reinforced concrete panel (membrane) element formulation to be used as a constitutive element in modeling of reinforced concrete members under plane stress, v) a simplified finite element modeling approach to simulate the behavior of structural walls with various configurations and response characteristics.
Dr. Sami A. Kılıç has collaborated with the industry on the mine blast resistance of armoured carriers in a multi-disciplinary project involving mechanical and civil engineers. He also took part in the European Union’s Cooperation on Science and Technology COST Action 26 entitled “Urban Habitat Constructions under Catastrophic Events”, and collaborated with international experts within Working Group 3: “Impact and Explosion Resistance”. His current research activities involve the blast resistant design of reinforced concrete slabs, seismic response of long-span suspension bridges, and earthquake-resistant design of tall reinforced concrete industrial chimneys, which is supported by the CICIND International Committee for Industrial Chimneys Organisation (“Comité International des Cheminées Industrielles”).
Seismic Risk Reduction
As Turkey is a country of high seismicity, research on seismic risk reduction has always been a top priority. Issues regarding earthquake resistant design, innovative retrofitting strategies, modeling of inelastic structural behavior and estimation of seismic hazard are the main components of this interdisciplinary reserach area.
Dr. Serdar Soyöz is mainly working on probabilistic seismic hazard analysis and loss estimation, experimental and analytical studies on bridges, industrial facilities, cold-formed structures and historical structures; base isolation and damping devices.
Dr. Hilmi Luş's research in the area of earthquake risk reduction focuses on economic implications of retrofitting schemes and insurance. When dealing with earthquake risks that are inherently highly uncertain, analysis of the feasibility of retrofitting schemes in economic terms has proved to be a signficant driver of mitigation decisions both on the micro level (building scale) and the macro level (city scale). Estimation of performance and accurate analysis of improvements obtained by mitigation technologies also have significant implications for the insurance sector, especially in the wake of a catastrophic event such as a significant earthquake.
Structural Fire Safety
Structural Fire Engineering is an important multi-disciplinary engineering field that deals with fire science and structural resistance of buildings, bridges and other infrastructure. Natural hazard mitigation is one of the funded activities in ‘Environment European Research Area’. Fire represents one of the most severe environmental hazards for the built infrastructure and it is a particularly dangerous event caused by many other hazards such as earthquake, impact and blast.
Dr. Serdar Selamet's research group focuses on natural hazard risk mitigation through utilizing the fundamental knowledge of theoretical, computational and experimental mechanics of structures and fire science. The group studies the fire performance of structures, especially the fire resilience of structural steel connections in a composite floor, which provide integrity and stability to the global structural system. Another area of focus is the study of progressive collapse of tall buildings due to various fire scenarios. A transient heat transfer finite element software called FEHEAT is currently being developed by Dr. Selamet's group.
Structural Health Monitoring
Structural Health Monitoring (SHM) is the name given to efforts that use field measurements to identify and monitor the well-being of structures. It is an interdisciplinary and continuosly expanding research area that is beginning to be widely employed in monitoring of large scale civil engineering structures such as long bridges and tall buildings. Evaluation of structural integrity of critical structures after significant events such as large scale earthquakes is a significant tool for all decision makers and SHM will play an increasing role in such evaluations in the near future.
Dr. Hilmi Luş's research focus in the area of structural health monitoring is on system identification and damage detection. His work has dealt with the use of first order models for both operational and earthquake induced vibrations coupled with inverse transformations to obtain physical parameters such as mass and stifness distributions. Theoretical contributions to the field by Dr. Luş and coworkers include a new method for obtaining second order models using limited number of input and output measurements and new measures of mode shape similarity that are well correlated with changes in the flexibility matrix to be used for clustering and damage detection purposes.
Dr. Serdar Soyöz is mainly working on instrumentation, real-time monitoring and identification of structures such as tall buildings, bridges, industrial facilities, historical structures, wind turbines; development of methodologies and software for FEM updating and damage detection.