Gülkan, Hakkı Polat

Gülkan, Hakkı Polat

Profile URL

https://hdl.handle.net/20.500.12416/9312

Name Variants

Gulkan, H. Polat
Gulkan, Polat
Gülkan, Polat
Gülkan, Hakkı Polat
Gülkan, P.
Gülkan, Hakkı Polat
Polat, Gülkan
Gulkan, P.
Gülkan, Hakkı Polat
Gülkan, Hakkı Polat

Job Title

Prof. Dr.

Main Affiliation

06.05. İnşaat Mühendisliği
06. Mühendislik Fakültesi
01. Çankaya Üniversitesi
06.05. İnşaat Mühendisliği
İnşaat Mühendisliği
06. Mühendislik Fakültesi
01. Çankaya Üniversitesi

Status

Former Staff

Full item page

Sustainable Development Goals

13

CLIMATE ACTION

0

Research Products

8

DECENT WORK AND ECONOMIC GROWTH

0

Research Products

3

GOOD HEALTH AND WELL-BEING

0

Research Products

15

LIFE ON LAND

0

Research Products

17

PARTNERSHIPS FOR THE GOALS

0

Research Products

14

LIFE BELOW WATER

0

Research Products

4

QUALITY EDUCATION

0

Research Products

11

SUSTAINABLE CITIES AND COMMUNITIES

7

Research Products

6

CLEAN WATER AND SANITATION

0

Research Products

10

REDUCED INEQUALITIES

0

Research Products

9

INDUSTRY, INNOVATION AND INFRASTRUCTURE

0

Research Products

12

RESPONSIBLE CONSUMPTION AND PRODUCTION

0

Research Products

2

ZERO HUNGER

0

Research Products

1

NO POVERTY

0

Research Products

7

AFFORDABLE AND CLEAN ENERGY

0

Research Products

5

GENDER EQUALITY

0

Research Products

16

PEACE, JUSTICE AND STRONG INSTITUTIONS

0

Research Products

This researcher does not have a Scopus ID.

This researcher does not have a WoS ID.

Scholarly Output

26

Articles

15

Views / Downloads

2575/126

Supervised MSc Theses

0

Supervised PhD Theses

0

WoS Citation Count

140

Scopus Citation Count

183

WoS h-index

8

Scopus h-index

9

Patents

0

Projects

0

WoS Citations per Publication

5.38

Scopus Citations per Publication

7.04

Open Access Source

3

Supervised Theses

0

Google Analytics Visitor Traffic

Journal	Count
Earthquake Spectra	5
Structural Engineering and Mechanics	2
15 WCEE	2
Earthquake Data in Engineering Seismology	1
Earthquake Engineering and Engineering Vibration	1

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Scholarly Output Search Results

Now showing 1 - 10 of 26

Citation - WoS: 2
Citation - Scopus: 2
Site-Structure Resonance as a Proxy for Structural Damage
(Earthquake Engineering Research inst, 2011) Lang, Dominik H.; Schwarz, Jochen; Gulkan, Polat
Since 1992, the reconnaissance teams of the German Task Force for Earthquakes have undertaken numerous field missions to disaster areas after strong earthquakes worldwide. During these missions, a unique database of damage cases has been collected, which serves as the basis for examining whether site-structure resonance effects contribute to building damage. The selected buildings that partly experienced slight to moderate damage during a recent major event have been experimentally tested in order to identify their structural parameters and to allow a calibration of the structural building models. In addition, instrumental noise recordings were made directly at the building sites to derive the ranges of predominant site periods. By correlating the ranges of predominant site periods with the building's capacity curves, representing the inelastic displacement behavior under lateral effects, a quick survey procedure has been developed to estimate the impact of agreements between periods of the site and the structure contributing to structural earthquake damage. [DOI: 10.1193/1.3651403]
High-velocity impact of large caliber tungsten projectiles on ordinary Portland and calcium aluminate cement based HPSFRC and SIFCON slabs. Part I: experimental investigations
(Techno-Press, 2011) Polat, Gülkan; Korucu, Hasan
Impact experiments have been carried out on concrete slabs. The first group was traditionally manufactured, densely reinforced concrete targets, and the next were ordinary Portland and calcium aluminate cement based HPSFRC (High performance steel fiber reinforced concrete) and SIFCON (Slurry infiltrated concrete) targets. All specimens were hit by anti-armor tungsten projectiles at a muzzle velocity of over 4 Mach causing destructive perforation. In Part I of this article, production and experimental procedures are described. The first group of specimens were ordinary CEM I 42.5 R cement based targets including only dense reinforcement. In the second and third groups, specimens were produced using CEM I 42.5 R cement and Calcium Aluminate Cement (CAC40) with ordinary reinforcement and steel fibers 2 percent in volume. In the fourth group, SIFCON specimens including 12 percent of steel fibers without reinforcement were tested. A high-speed camera was used to capture impact and residual velocities of the projectile. Sample tests were performed to obtain mechanical properties of the materials. In the companion Part II of this study, numerical investigations and simulations performed will be presented. Few studies exist that examine high-velocity impact effects on CAC40 based HPSFRC targets, so this investigation gives an insight for comparison of their behavior with Portland cement based and SIFCON specimens
Citation - WoS: 22
Citation - Scopus: 26
A Dispassionate View of Seismic-Hazard Assessment
(Seismological Soc Amer, 2013) Gulkan, Polat
Citation - WoS: 4
Citation - Scopus: 6
High-Velocity Impact of Large Caliber Tungsten Projectiles on Ordinary Portland and Calcium Aluminate Cement Based Hpsfrc and Sifcon Slabs. Part Ii: Numerical Simulation and Validation
(Techno-press, 2011) Gulkan, P.; Korucu, H.
We present the numerical implementation, simulation, and validation of the high-velocity impact experiments that have been described in the companion article. In this part, numerical investigations and simulations performed to mimic the tests are presented. The experiments were analyzed by the explicit integration-based software ABAQUS for improved simulations. Targets were modeled with a damaged plasticity model for concrete. Computational results of residual velocity and crater dimensions yielded acceptable results.
Citation - WoS: 7
Citation - Scopus: 11
Scaling Legitimacy for Design of Lead Rubber Bearing Isolated Structures Using a Bounding Analysis
(Earthquake Engineering Research inst, 2016) Ozdemir, Gokhan; Gulkan, H. Polat
In dynamic analyses, although there is no limitation for scale factors, the customary values vary from 0.25 to 4. However, these values are based on subjective judgments rather than a quantitative evaluation. This study focused on scaling legitimacy of acceleration time series to be used in dynamic analyses performed during the design of lead rubber bearing (LRB) isolated structures, to obtain a limit for scale factors. For this purpose, several dynamic analyses are performed with the parameters, namely, isolation period, peak ground velocity, and site class. In the analyses, a recently proposed deteriorating hysteretic bilinear representation is used to model the behavior of LRBs. Limitation for scale factors is discussed through the concept of bounding analysis that intends to provide design envelopes for response quantities of isolated structures. As a result, limits for scale factors, providing that the bounding analysis fulfills its intended purpose in design of LRBs, are proposed.
Citation - WoS: 26
Citation - Scopus: 36
Deformation Limits for Structural Walls With Confined Boundaries
(Earthquake Engineering Research inst, 2012) Kazaz, Ilker; Gulkan, Polat; Yakut, Ahmet
For accurate analytical assessment of performance and damage in reinforced concrete members, well-defined deformation limits at particular damage states are required. With advanced and computationally intensive finite element analyses, we establish deformation limits at yield and ultimate limit states for adequately confined rectangular reinforced concrete structural walls in terms of drift ratio, plastic rotation, and curvature. To investigate the deformation limits of structural walls, a parametric study on isolated cantilever wall models is performed. The primary variables of the parametric study are the shear-span-to-wall-length ratio, wall length, axial load ratio, normalized shear stress, the amount of horizontal web reinforcement, and the amount of longitudinal reinforcement at the confined boundary of structural wall models. Expressions and limit values are proposed for yield and ultimate deformation capacity of structural walls, based on the most influential parameters. The proposed equations are found to be promising when compared to results of experiments. [DOI: 10.1193/1.4000059]
Fragility of Shear Wall Buildings with Torsional Irregularity
(2012) Akansel, Vesile Hatun; Yakut, Ahmet; Gülkan, Polat
Fragility curves are useful for damage assessment of structures. There are many criteria that affect the reliability of fragility curves such as transitional damage states, plan irregularity and different measures of seismic intensity. Determination of fragility of a shear wall structure is important, especially for installations that have torsional irregularity. In this study fragility curves of a shear wall building with torsional irregularity have been obtained. This building was subjected to synthetic earthquake motions on the AZALEE shaking table under the coordination of CEA (Commissariat à l’Energie Atomique) and Electricité de France (EDF) in Saclay, Paris under the scope of the SMART program. Maximum inter-story drift values have been used as the damage indicator to obtain the fragility curves and different seismic intensity measures such as PGA, PGV, PGD and CAV have been used. Thirty bi-directional horizontal ground motions have been applied for the time history analyses. These synthetic acceleration sets applied to the structure have different amplitudes in the range of 0.1 to 1 g. Micro modeling approach has been used to obtain reasonably accurate and consistent results with experiments. ANSYS finite element software has been used for the response history analyses. Fragility curves of shear wall building have been calculated according to pre-established damage indicators. The limits are light, controlled and extended damage indicators. These curves are compared with those of the HAZUS damage states for correlation.
Buildings Subjected to Recurring Earthquakes: A Tale of Three Cities
(2011) Bayhan, Beyhan; Polat, Gülkan
Three different buildings built according to the same design have experienced three different near-field strong ground motions over a period of 11 years in three different cities in Turkey. The input motion was known for each because strong-motion sensors were located adjacent or close to the buildings. We examine the performance of the five-story, reinforced concrete-frame buildings. Bidirectional nonlinear time history and nonlinear static analyses on 3-D analytical models are performed. The principal focus is to assess whether the analytical model of the buildings could indicate column-beam damage consistent with that observed at the sites after the earthquakes. Results illustrate that nonlinear time history analyses are capable of indicating the occurrence of shear failure in captive columns; however, they overestimate the global damage. The overestimation is greater where the building sustained a pulse-type motion without significant distress. It appears that difference between visual observations and analytical results persists.
Citation - WoS: 8
Citation - Scopus: 9
Dynamic Shear Force Amplification in Regular Frame-Wall Systems
(Wiley-blackwell, 2016) Kazaz, Ilker; Gulkan, Polat
A parametric study is conducted to investigate the dynamic shear amplification factor (DAF) in low-to-mid-rise frame-wall systems in which the reinforcement curtailment along the height matches the required code strength. The level of frame-wall interaction is varied by changing the wall index, defined as the ratio of the total wall area to the floor plan area, in a generic frame-wall system, and its correlation with the DAF is investigated. Wall index values ranging in the 0.2% to 2% interval are selected. Walls with lengths of 3m, 5m and 8m are used in the design of model buildings of 4, 8 and 12 stories. Shear-flexure beam continuum formulation is used in design and modeling. The global behavior is analyzed using nonlinear response history procedure using spectrum compatible ground motions. It is found that the primary source of amplification is the level of inelastic demand on the system. Walls designed for code-specified force reduction factor R=6 experienced an average base shear force amplification in the order of 1.64 with standard deviation of 0.19 with respect to design shear force. Amplification diminishes with decreasing R. An expression for the dynamic amplification factor as a function of the number of stories and force reduction factor R is proposed. Copyright (C) 2015 John Wiley & Sons, Ltd.
Seismic behavior of a four-legged masonry minaret
(2012) Kazaz, İ.; Akansel, V.; Gülkan, Polat; Kazaz, E.
The four-legged Minaret of Sheikh Mutahhar Mosque has been constructed in the early 16th century during the Aq Qoyunlu Period in Diyarbakır, Turkey, which is located in the second most hazardous zone of the Turkish Seismic Zones Map. This is a special structure, because the minaret body has been placed on four cylindrical stone columns. Therefore, this minaret is seemingly vulnerable though it has survived for five centuries. We use the square cross sectioned minaret as a possible large-scale seismograph to examine the possible limits of ground motion that must have affected it without causing its collapse. In order to investigate the likely seismic performance and strength of the four-legged minaret, a model, which is very close to real structure, was generated with explicit dynamic code LS-DYNA. The developed model takes into account the material nonlinearities and the interface friction and contact behavior between the masonry units. It was displayed that the amplitude of the ground motion in Diyarbakır could not be 0.15g.

Gülkan, Hakkı Polat

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Sustainable Development Goals

13

CLIMATE ACTION

0

Research Products

8

DECENT WORK AND ECONOMIC GROWTH

0

Research Products

3

GOOD HEALTH AND WELL-BEING

0

Research Products

15

LIFE ON LAND

0

Research Products

17

PARTNERSHIPS FOR THE GOALS

0

Research Products

14

LIFE BELOW WATER

0

Research Products

4

QUALITY EDUCATION

0

Research Products

11

SUSTAINABLE CITIES AND COMMUNITIES

7

Research Products

6

CLEAN WATER AND SANITATION

0

Research Products

10

REDUCED INEQUALITIES

0

Research Products

9

INDUSTRY, INNOVATION AND INFRASTRUCTURE

0

Research Products

12

RESPONSIBLE CONSUMPTION AND PRODUCTION

0

Research Products

2

ZERO HUNGER

0

Research Products

1

NO POVERTY

0

Research Products

7

AFFORDABLE AND CLEAN ENERGY

0

Research Products

5

GENDER EQUALITY

0

Research Products

16

PEACE, JUSTICE AND STRONG INSTITUTIONS