Papers by Ahmet Hilmi DERİNGÖL
Combined Efect of Bearing Stifness of the Base Isolator and Damping Characteristics of the Viscous Damper on the Nonlinear Response of Buildings
International Journal of Steel Structures, 2022
Recently, the base isolation system (BIS) has been adopted as mature structural protective system... more Recently, the base isolation system (BIS) has been adopted as mature structural protective system which dissipates the most
part of the input energy emerged during any type of seismic excitation. However, BIS can induce large displacement because
of having easily movement tendency of the bearing. Therefore, this study proposes a set of BIS incorporated with supplementary damping device to control the nonlinear response of the buildings with low and moderate heights. For this, 5 and
10-storey steel moment resisting frames isolated with lead rubber bearing (LRB) with varying stifness properties (i.e. high,
moderate, and low) were studied. Afterwards, viscous damper (VD) was designed with three diferent damping exponents of
0.3, 0.6, and 1.0 so that they were alternatively distributed both in inner and corner bays throughout the building heights. The
efectiveness of the proposed isolation models with and without VDs were evaluated through the nonlinear time history analyses under diferent earthquake records. Advantages of the developed isolation systems over both the fxed base and the base
isolated frames were discussed in terms of the storey, bearing, and relative displacements, roof and interstorey drift ratios,
absolute acceleration, base shear, and hysteretic curves. It was shown that low-stifness-LRB (LLRB) associated with the
VD of proper damping exponent and implementation layout signifcantly mitigated the structural response of the buildings.
Enhancing the seismic performance of high-rise buildings with lead rubber bearing isolators
Recent earthquakes have enforced the engineering community to design seismically more efficient b... more Recent earthquakes have enforced the engineering community to design seismically more efficient buildings through the energy dissipation systems. For this purpose, this paper investigates the seismic behavior of a high-rise building with a series of base isolation systems. Firstly, a 20-storey steel frame is selected as a fixed-base building, and then equipped with lead rubber bearings (LRBs). In the modelling of LRB, isolation period is alternatively varied as 4, 4.5, and 5 sec to evaluate the effectiveness of the isolator characteristic on the seismic performance of the high-rise base-isolated buildings. The seismic responses of the fixed-base and base-isolated buildings evaluated through a series of time-history analyses are performed using natural ground motion records. The analysis results are compared using engineering demand parameters such as storey displacement, isolator displacement, relative displacement, roof drift, interstorey drift ratio, absolute acceleration, base shear, base moment, input energy, and hysteretic curve. It is revealed that adjusting the isolation period in the design of LRB improved the seismic performance of the base-isolated high-rise steel buildings.
Structures, 2021
Recently, many buildings have originally been designed as base-isolated to mitigate the structura... more Recently, many buildings have originally been designed as base-isolated to mitigate the structural vibration. However, buildings with base isolation systems can undergo displacement/amplification demand due to the inherent nonlinear behaviour of the base isolators, especially in earthquake-prone regions. Hence, in some cases it could be necessary to control the seismic response of the base-isolated buildings using supplemental damping device. This paper investigated the effectiveness of nonlinear fluid viscous damper (NFVD) considering design parameters for the base-isolated buildings with lead rubber bearing (LRB). For this, 10-storey benchmark steel moment resisting frame isolated with LRB having a series of isolation periods (T) of 3, 3.5, 4, and 5 s was used. These base-isolated frames consist of three bays and NFVDs having different damping exponents (α) of 0.15, 0.30, 0.50, and 0.70 were inserted in the mid, corner, and all bays of each base-isolated frame at the ground level. The case studied frames were modelled with a finite element program in which LRB elements were characterized by bi-linear hysteretic behaviour while NFVD elements were represented considering the Maxwell model having an elastic spring and a viscous dashpot in series. The nonlinear response of the frames with LRB and NFVD were evaluated by the nonlinear time history analyses using five ground motion records. The analysis of the results were comparatively evaluated considering certain engineering demand parameters such as the storey, bearing, and relative displacements, roof and inter-storey drift ratios, absolute acceleration, base shear, base moment, input energy, and hysteretic curves. One of the main findings of this study is that the base-isolated building with the passive damping device as control attenuation satisfactorily responded when associated with appropriated design parameters.
International Journal of Steel Structures, 2021
In this study, the use of high damping rubber bearing (HDRB) with various design properties in mi... more In this study, the use of high damping rubber bearing (HDRB) with various design properties in mitigating the seismic effects
for steel buildings was investigated. For this, a generalized demand on the analytical model of HDRB was introduced and
eighteen different models of HDRB were examined comparatively. These models were created by considering three significant
isolation parameters of HDRB such as isolation period T (2, 2.5, and 3 s), effective damping ratio β (0.05, 0.10, 0.15), and
post-yield stiffness ratio λ (3 and 6). The benchmark low (3-storey), mid (6-storey), and high-rise (9-storey) steel buildings
were equipped with different isolation systems of HDRB and then subjected to a set of earthquake ground motions through
nonlinear time history analyses in order to evaluate the actual nonlinear behaviour of the bearings in the base-isolated steel
buildings in service. The base-isolated frames were assessed by the variation of the selected structural response parameters
such as isolator displacement, relative displacement, inter-storey drift ratio, absolute acceleration, base shear, hysteretic
curve, and dissipated energy. The effectiveness of the isolation parameters on the nonlinear response of the steel buildings
with HDRB under earthquakes was comparatively evaluated to generate alternatively innovative isolation system. It was
shown that the seismic performance of the base-isolated structure was remarkably influenced by the isolation parameters.
The most favourable base isolation model was obtained when the higher value of the isolation period and effective damping
ratio combined with the low post-yield stiffness ratio.
Journal of Constructional Steel Research , 2020
This study addresses the nonlinear seismic responses of ordinary moment frames upgraded with a se... more This study addresses the nonlinear seismic responses of ordinary moment frames upgraded with a series of passive protective systems. To this, friction damper (FD) as an energy dissipation device and lead rubber bearing (LRB), friction pendulum bearing (FPB), and high damping rubber bearing (HDRB) as base isolators were considered. The effectiveness of the isolation systems together with the dampers was investigated comparatively. For this purpose, eight different cases were taken into account. The first case contains a five storey steel ordinary moment frame considered as fixed-base (FB), the other four cases are the single use of FD, LRB, FPB, and HDRB in such frame, and the last three cases include the upgrading of the frame with the combination of FD with each of the base isolation systems. They are modelled using a finite element program, and evaluated by the nonlinear time history analyses in which seven ground motion records were adopted. The seismic performance of the passive protective systems was evaluated by the engineering demand parameters such as storey displacement, bearing displacement, relative displacement, roof drift ratio, interstorey-drift ratio, absolute acceleration, base shear, base moment, hysteretic curve, and energy dissipation. One of the main outcomes of this study was that single protective system could not always satisfy fully operational performance level, while the combined systems of the base isolation with friction damper effectively achieved for the case study frame. Furthermore, the numerical results showed that the combined systems were capable of limiting the inter-storey drift without increasing the absolute accelerations.
Soil Dynamics and Earthquake Engineering, 2019
This study investigates the influence of the friction pendulum bearing (FPB) isolator characteris... more This study investigates the influence of the friction pendulum bearing (FPB) isolator characteristics on the
nonlinear response of the buildings under various seismic excitations. To represent a wide range of assessment,
3, 6, and 9-storey steel framed buildings with twenty seven different isolation models of FPB were studied by
identifying the local and global deformations. Three important parameters such as isolation period T (as 2, 2.5,
and 3 s), effective damping ratio ß (as 0.05, 0.15, 0.25), and yield strength ratio Fy/W (as 0.025, 0.05, and 0.10)
were used in the modelling of FPB. Two-dimensional model of the base-isolated steel frames were created and
the nonlinear time history analysis was performed through a number of earthquake ground motions. The behaviour
of the isolated frames was measured by the variation of isolator displacement, roof drift ratio, relative
displacement, interstorey drift ratio, absolute acceleration, base shear, base moment, hysteretic curve, and
dissipated energy. The benefits obtained through the adoption of the base isolation system were discussed. It was
found that the seismic response of the base-isolated frames could be estimated accurately by adjusting the proper
isolation period, yield strength ratio, and effective damping ratio for the case studied structures.
INTERNATIONAL ADVANCED RESEARCHES and ENGINEERING JOURNAL, 2018
Many researchers have already acknowledged that the base isolation system as the most feasible an... more Many researchers have already acknowledged that the base isolation system as the most feasible and economical method for civil engineering structures exposed to the seismic excitation. The Friction Pendulum Systems (FPS) have steel concave surface connected with articulated friction slider and utilized the concept of pendulum for lengthening the period of the superstructure so as to dissipate the seismic energy. The present study investigates on various design approaches for the evaluation of the seismic response of steel frames equipped with FPS. The response of isolated frames is simply adjusted by several parameters such as the friction coefficient (μ), the radius of curvature (R), the isolation period (T) and the axial load and so 2D, three bay 3 and 7-storey steel moment resisting frames (SMRF) are designated as isolated frames in order to examine the effect of variation of the R and the friction coefficient on the seismic response of the isolated frames. The R and μ are predefined as 1, 1.55, 2.25 and 0.025, 0.05, 0.1, respectively. The seismic response of the modelled isolation systems has been evaluated through nonlinear time history analyses, a set of ground motions using SAP2000 software. The local and global deformations are employed to compare the seismic performance of different isolation frames through nonlinear analysis. The results showed that the isolated frames having greatest radius of curvature with lowest friction coefficient exhibited better seismic performance than other models in terms of the local and global deformations.
Earthquakes and Structures, 2018
In this paper, an analytical study was carried out to propose an optimum base-isolated system for... more In this paper, an analytical study was carried out to propose an optimum base-isolated system for the design of steel
structures equipped with lead rubber bearings (LRB). For this, 5 and 10-storey steel moment resisting frames (MRFs) were
designed as Special Moment Frame (SMF). These two-dimensional and three-bay frames equipped with a set of isolation
systems within a predefined range that minimizes the response of the base-isolated frames subjected to a series of earthquakes.
In the design of LRB, two main parameters, namely, isolation period (T) and the ratio of strength to weight (Q/W) supported by
isolators were considered as 2.25, 2.5, 2.75 and 3 s, 0.05, 0.10 and 0.15, respectively. The Force-deformation behavior of the
isolators was modelled by the bi-linear behavior which could reflect the nonlinear characteristics of the lead-plug bearings. The
base-isolated frames were modelled using a finite element program and those performances were evaluated in the light of the
nonlinear time history analyses by six natural accelerograms compatible with seismic hazard levels of 2% probability of
exceedance in 50 years. The performance of the isolated frames was assessed in terms of roof displacement, relative
displacement, interstorey drift, absolute acceleration, base shear and hysteretic curve.
Journal of Constructional Steel Research, 2018
The present study evaluates the seismic performance of steel moment resisting frames (MRFs) upgra... more The present study evaluates the seismic performance of steel moment resisting frames (MRFs) upgraded with different structural protective systems. For this, three 5 storey steel MRFs (Ordinary moment frame (OMF), intermediate moment frame (IMF) and special moment frame (SMF)) and two 10 storey MRFs (IMF and SMF) were studied. As structural protective systems, friction dampers (FDs), base isolation with lead rubber bearings (LRBs), and a combination of them were considered. The structures were modeled using a finite element program and evaluated by the nonlinear time history analyses. In the nonlinear time history analyses, seven natural were taken into account. Roof drift, roof absolute acceleration, relative displacement, interstorey drift ratio, base shear, top storey moment, and hysteretic curve were employed to compare the elastic and inelastic responses of all frames. The results clearly highlighted that the application of FDs with LRB had remarkable improvement in the earthquake performance of the case study frames reducing the local/global damages in the main structural systems and satisfied the serviceability (i.e., fully operational, FO and operational, OP) limit states as well.
International Advanced Researches & Engineering Congress, 2017
Recently, as a passive energy dissipation devices many base isolation (BI) systems have been prop... more Recently, as a passive energy dissipation devices many base isolation (BI) systems have been proposed and capably adopted for curbing the earthquake response. The concept of (BI) depends on decoupling the structure from the catastrophic effect of the seismic excitations. This paper presents an analytical study was carried out in order to propose an optimum base isolated isolation system for the steel structures with lead rubber bearings. Hence, 5-storey steel moment resisting frames (MRFs) designed as Ordinary Moment Frame (OMF). These two-dimensional and three-bay frames equipped with a set of isolation system within predefined range that minimizes the response of the base isolated frames subjected to a series of earthquakes. As (BI) system, Lead Rubber Bearing (LRB) is selected. In the design of LRB, two main parameters, namely, isolation period (T) and ratio of strength to weight (Q/W) supported by isolators were considered as 2.5, 3 and 3.5 s, 0.06, 0.12 and 0.18, respectively. Further the force-deformation behaviour of the isolators was modelled by the bi-linear behaviour which could reflect the nonlinear characteristics of the lead-plug bearings and effectively used to model all isolation systems. The base isolated frames were modelled using a finite element program and those performances were analyzed by means of the nonlinear time history analyses, a series natural accelerograms compatible with seismic hazard levels of 2% probability of exceedance in 50 years were considered. The performance of the isolated frames were evaluated by the variation of roof displacement, relative displacement, interstorey drift and absolute acceleration. Compared with other isolation models, the isolation periods of 2.5 and 3 s with yield strength ratio of 0.06 that significantly improved the seismic performance of fixed base frame.
International Advanced Researches & Engineering Congress, 2017
Many researchers have already acknowledged the base isolation system as the most feasible and eco... more Many researchers have already acknowledged the base isolation system as the most feasible and economical method for civil engineering structures exposed to the seismic excitation. The Friction Pendulum Systems (FPS) have steel concave surface connected with articulated friction slider and that utilized the concept of pendulum for lengthening the period of the superstructure so as to dissipate the seismic energy. The present study investigates on various design approaches for the evaluation of the seismic response of steel frames equipped with FPS. The response of isolated frames is simply adjusted by several parameters such as the friction coefficient (, the radius of curvature (R) and the axial load and so 2D, three bay 3 and 7-storey steel moment resisting frames (SMRF) are designated as isolated frames in order to examine the effect of variation of the R and the friction coefficient on the seismic response of the isolated frames. The R and the friction coefficient are predefined as 1, 1.55, 2.25 and 0.025, 0.05, 0.1, respectively. The seismic response of the modelled isolation systems has been evaluated through nonlinear time history analyses, a set of ground motions using SAP2000 software. The local and global deformations are employed to compare the seismic performance of different isolation frames through nonlinear analysis. The results showed that the isolated frames having greatest radius of curvature with lowest friction coefficient exhibited better seismic performance than other models in terms of the local and global deformations.
1st International Conference on Engineering Technology and Applied Sciences, 2016
In this study, the seismic behaviour of the base isolated frames was investigated comparatively t... more In this study, the seismic behaviour of the base isolated frames was investigated comparatively through nonlinear time history analysis. For this, two-dimensional five-storey and three-bay steel moment frames equipped with lead rubber bearing (LRB) isolators were used. The force-deformation behaviour of the isolators was modelled by the bi-linear behaviour which could reflect the nonlinear characteristics of the lead-plug bearings and effectively used to model all isolation systems. In the design of LRB, two main parameters, namely, isolation period (T) and ratio of strength to weight (Q/W) supported by isolators were considered as 2.0, 2.5 and 3 s, 0.04, 0.07 and 0.10, respectively. The fixed base and base isolated frames were modelled using a finite element program. In the analysis, three different natural ground motions were employed. The performance of the case study structures were measured by the variation of roof displacement, relative displacement, interstorey drift and hysteretic curve.
1st International Conference on Engineering Technology and Applied Sciences, 2016
Friction damping devices are relatively inexpensive and effective method for energy dissipation t... more Friction damping devices are relatively inexpensive and effective method for energy dissipation through the mechanism of solid friction generated at the sliding surface. It is crucial to provide a steady and predictable frictional response during the life of these devices. In this study, a numerical analysis was performed in order to investigate the placement of the friction dampers (FDs) on the behaviour of the structure under seismic loading. For this, 3 and 6 storey steel buildings with moment-resisting frames were taken into consideration. The case study buildings have the same plan and three bays on each direction. Two structures equipped with FDs placed in various locations throughout the structure were subjected to the earthquake loading. The structures were modelled using a finite element program and evaluated by the nonlinear analysis. The response of the structures in terms of local and global deformations was evaluated. The results exhibited that the damper placement in the structure had a considerable influence on the structural response of the frames under earthquake loading.
2. Türkiye Deprem Mühendisliği ve Sismoloji Konferansı, 2013
Bu çalışmada, farklı özelliklere sahip moment aktarabilen çerçeve sistemli yapılar ile bunlara so... more Bu çalışmada, farklı özelliklere sahip moment aktarabilen çerçeve sistemli yapılar ile bunlara sonradan ilave edilen sürtünme sönümleyicili yapıların deprem etkisi altındaki yapısal tepkileri lineer olmayan dinamik analiz kullanılarak karşılaştırmalı olarak incelenmiştir. Bu amaçla, 4 ve 8 katlı moment aktarabilen çerçeveli çelik yapılar araştırmada kullanılmıştır. Yapılar aynı kat planına sahip olup, her iki yönde de 3 eşit açıklıktan oluşmaktadır. Mevcut çelik yapılar iki farklı durum için tasarlanmıştır. Bunlar esnek moment aktarabilen çerçeveli ve rijit moment aktarabilen çerçeveli yapılar olarak sıralanmaktadır. Sürtünme sönümleyiciler çerçevelerin yüksekliği boyunca yerleştirilmiştir. Böylece, toplam 4 farklı durum için dinamik analizler gerçekleştirilmiştir. Herbir çerçeve sistemi için deprem etkisi altında katlara göre yerdeğiştirme, göreli kat ötelenme zarf eğrisi ve sürtünme sönümleyiciler için elde edilen histeretik eğriler karşılaştırmalı olarak incelenmiştir. Elde edilen sonuçlara göre, çerçeve sisteminin tasarım özelliklerine bağlı olarak sürtünme sönümleyici bulunduran çerçevelerin yapısal performanslarında önemli düzeyde iyileşmeler gözlenmiştir.
Madde 1-4734 sayılı Kamu İhale Kanununun 53 üncü maddesinin (b) fıkrasının ikinci bendine dayanıl... more Madde 1-4734 sayılı Kamu İhale Kanununun 53 üncü maddesinin (b) fıkrasının ikinci bendine dayanılarak hazırlanmış olan bu Genel Şartnamenin amacı, iş sahibi idareler tarafından 4735 sayılı Kamu İhale Sözleşmeleri Kanununa göre sözleşmeye bağlanan her türlü yapım işinin yürütülmesinde uygulanacak genel esasları tespit etmektir.
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Papers by Ahmet Hilmi DERİNGÖL
part of the input energy emerged during any type of seismic excitation. However, BIS can induce large displacement because
of having easily movement tendency of the bearing. Therefore, this study proposes a set of BIS incorporated with supplementary damping device to control the nonlinear response of the buildings with low and moderate heights. For this, 5 and
10-storey steel moment resisting frames isolated with lead rubber bearing (LRB) with varying stifness properties (i.e. high,
moderate, and low) were studied. Afterwards, viscous damper (VD) was designed with three diferent damping exponents of
0.3, 0.6, and 1.0 so that they were alternatively distributed both in inner and corner bays throughout the building heights. The
efectiveness of the proposed isolation models with and without VDs were evaluated through the nonlinear time history analyses under diferent earthquake records. Advantages of the developed isolation systems over both the fxed base and the base
isolated frames were discussed in terms of the storey, bearing, and relative displacements, roof and interstorey drift ratios,
absolute acceleration, base shear, and hysteretic curves. It was shown that low-stifness-LRB (LLRB) associated with the
VD of proper damping exponent and implementation layout signifcantly mitigated the structural response of the buildings.
for steel buildings was investigated. For this, a generalized demand on the analytical model of HDRB was introduced and
eighteen different models of HDRB were examined comparatively. These models were created by considering three significant
isolation parameters of HDRB such as isolation period T (2, 2.5, and 3 s), effective damping ratio β (0.05, 0.10, 0.15), and
post-yield stiffness ratio λ (3 and 6). The benchmark low (3-storey), mid (6-storey), and high-rise (9-storey) steel buildings
were equipped with different isolation systems of HDRB and then subjected to a set of earthquake ground motions through
nonlinear time history analyses in order to evaluate the actual nonlinear behaviour of the bearings in the base-isolated steel
buildings in service. The base-isolated frames were assessed by the variation of the selected structural response parameters
such as isolator displacement, relative displacement, inter-storey drift ratio, absolute acceleration, base shear, hysteretic
curve, and dissipated energy. The effectiveness of the isolation parameters on the nonlinear response of the steel buildings
with HDRB under earthquakes was comparatively evaluated to generate alternatively innovative isolation system. It was
shown that the seismic performance of the base-isolated structure was remarkably influenced by the isolation parameters.
The most favourable base isolation model was obtained when the higher value of the isolation period and effective damping
ratio combined with the low post-yield stiffness ratio.
nonlinear response of the buildings under various seismic excitations. To represent a wide range of assessment,
3, 6, and 9-storey steel framed buildings with twenty seven different isolation models of FPB were studied by
identifying the local and global deformations. Three important parameters such as isolation period T (as 2, 2.5,
and 3 s), effective damping ratio ß (as 0.05, 0.15, 0.25), and yield strength ratio Fy/W (as 0.025, 0.05, and 0.10)
were used in the modelling of FPB. Two-dimensional model of the base-isolated steel frames were created and
the nonlinear time history analysis was performed through a number of earthquake ground motions. The behaviour
of the isolated frames was measured by the variation of isolator displacement, roof drift ratio, relative
displacement, interstorey drift ratio, absolute acceleration, base shear, base moment, hysteretic curve, and
dissipated energy. The benefits obtained through the adoption of the base isolation system were discussed. It was
found that the seismic response of the base-isolated frames could be estimated accurately by adjusting the proper
isolation period, yield strength ratio, and effective damping ratio for the case studied structures.
structures equipped with lead rubber bearings (LRB). For this, 5 and 10-storey steel moment resisting frames (MRFs) were
designed as Special Moment Frame (SMF). These two-dimensional and three-bay frames equipped with a set of isolation
systems within a predefined range that minimizes the response of the base-isolated frames subjected to a series of earthquakes.
In the design of LRB, two main parameters, namely, isolation period (T) and the ratio of strength to weight (Q/W) supported by
isolators were considered as 2.25, 2.5, 2.75 and 3 s, 0.05, 0.10 and 0.15, respectively. The Force-deformation behavior of the
isolators was modelled by the bi-linear behavior which could reflect the nonlinear characteristics of the lead-plug bearings. The
base-isolated frames were modelled using a finite element program and those performances were evaluated in the light of the
nonlinear time history analyses by six natural accelerograms compatible with seismic hazard levels of 2% probability of
exceedance in 50 years. The performance of the isolated frames was assessed in terms of roof displacement, relative
displacement, interstorey drift, absolute acceleration, base shear and hysteretic curve.