Journal Articles in
SCI Expanded (International Journals)
1- Darılmaz K, Orakdöğen E, Girgin K,
"Saint-Venant torsion of arbitrarily shaped orthotropic composite or FGM
sections by a hybrid finite element approach", Acta
Mechanica, Vol:229, Issue:3, Pages: 1387-1398, Mar
2018. DOI: 10.1007/s00707-017-2067-1 .
Scopus | Google
Scopus | Google
2- Girgin, K.,"Simplified formulations for the determination of
rotational spring constants in rigid spread footings resting on tensionless
soil", Journal of Civil Engineering and Management, Vol:23,
Issue 4, pp. 464-474, April 2017.
Scopus | Google | pdf
Scopus | Google | pdf
3- Girgin, Z. C., Girgin, K., "A Design-Oriented Combined Model
(7 MPa to 190 MPa) for FRP-Confined Circular Short Columns." Polymers, Vol.
7, No. 10, pp. 1905-1917, 2015.
Scopus | Google
Scopus | Google
4- Girgin K., Girgin Z.C., Aksoylu M.G., "Research on the normality of the plastic strain vector to the yield surface in RC sections", Materials and Structures ,Vol. 47, pp.1115–1130, 2014. DOI 10.1617/s11527-013-0116-3
Link
5- Aksoylu M.G., Girgin K.,"A load increment method for ductile reinforced concrete (RC) frame structures considering strain hardening effects", Structural Engineering and Mechanics, pp.231-247, Vol.38, No.2, 2011.
Scopus | Google
6- Orakdogen E., Girgin K., Boduroglu M.H., Buyukşişli B., Gokçe T., "Performance evaluation of a strengthened building considering the soil-structure interaction", Journal of Earthquake Engineering, pp.222-233, Vol.12:1 (S2), January 1, 2008.
Scopus | Google
7- Girgin K., Ozmen G., "Effective lengths of braced frames", Structural Engineering and Mechanics, pp.189-206, Vol.28, No.2, January 30, 2008.
Google | Link
8- Saygun A., Omurtag M.H., Orakdogen E., Girgin K., Kuçukarslan S., Darilmaz K.,"Simplified Solution of the Torsional Rigidity of the Composite Beams by Using FEM", Advances in Structural Engineering, Volume 10, Number 5, pp. 467-473(7), October 2007.
Scopus |Google
9- Girgin K., Ozmen G., "Simplified procedure for determining buckling loads of three-dimensional framed structures", Engineering Structures, Vol.29, No.9, pp.2344-2352, September 2007.
Scopus | Google
10- Darilmaz K., Orakdogen E., Girgin K., Kuçukarslan S., "Torsional rigidity of arbitrarily shaped composite sections by hybrid finite element approach", Steel and Composite Structures, Vol.7, Number 3, pp. 241-251, June 2007.
Scopus | Google
11- Girgin K., "Free-vibration analysis of non-cylindrical helices with variable cross - section by using mixed FEM", Journal of Sound and Vibration, Vol.297, pp. 931-945, November 2006.
Scopus | Google
12- Girgin Z.C., Girgin K., "A numerical method for static and free-vibration analysis of non-uniform Timoshenko beam-columns", Canadian Journal of Civil Engineering, pp. 278-293, Vol.33, Number 3, March 2006.
Scopus | Google | CJCE
13- Girgin K., Ozmen G., Orakdogen E., "Buckling lengths of irregular frame columns", Journal of Constructional Steel Research, pp. 605-613,Vol.62, 2006.
Scopus | Google
14- Girgin Z.C., Girgin K., "A numerical method for static or dynamic stiffness matrix of non-uniform members resting on variable elastic foundations", Engineering Structures, pp.1373-1384, Vol.27, No.9, 2005.
Scopus | Google
15- Orakdogen E., Girgin K., "Direct determination of influence lines and surfaces by F.E.M", Structural Engineering and Mechanics, pp.279-292, Vol.20, No.3, June 20, 2005.
Scopus | Google
16- Ozmen G., Girgin K., "Buckling lengths of unbraced multi-storey frame columns", Structural Engineering and Mechanics, pp.55-71, Vol.19, No.1, January 10, 2005.
Scopus | Google
Journal Articles in SCI Expanded (National Journals)
1-Özmen G., Girgin K., Darılmaz K., "Slenderness Effect in Reinforced
Concrete Frames", TEKNIK DERGI, Vol. 26, No. 4 , Pages:
7241-7263, October 2015.
pdf
2- Girgin K., Ozmen G., "Effective lengths of columns in braced
multi-storey frames", TEKNIK DERGI, Vol. 19:1, Pages:
4333-4346, January 2008.
pdf
3- Girgin K., Olgun O., Darilmaz K., Omurtag M.H., "Dynamic
analysis of cylindrical and conical helices by mixed FEM ", TEKNIK
DERGI, Vol. 17, pp. 4003-4023, No. 4, October 2006.
Scopus | Google | pdf
Scopus | Google | pdf
Journal Articles in Engineering Index
1- Girgin K., Darilmaz K., "Seismic response of infilled framed
buildings using pushover analysis", ARI The Bulletin of the
Istanbul Technical University, Vol.54, No.5, July 2007.
Scopus | Google | pdf
Scopus | Google | pdf
Journal Articles in
Other International Refereed Journals
1- Ozmen G, Girgin K., Durgun Y., "Torsional irregularity in
multi-storey structures", International Journal of Advanced
Structural Engineering, DOI 10.1007/s40091-014-0070-5, Vol.6, September 17
2014.
Scopus | Google
Scopus | Google
Details of the Journal
Articles
Title: Saint-Venant torsion of arbitrarily shaped orthotropic composite or FGM
sections by a hybrid finite element approach
Author(s): Darilmaz K., Orakdogen E., Girgin K.
Source : ACTA MECHANICA
Document Type: Article
Language: English
Accession Number: WOS:000427279600020
DOI: 10.1007/s00707-017-2067-1
Abstract: The purpose of this study is to calculate the torsional rigidity and
maximum shear stresses of arbitrarily shaped orthotropic composite or
functionally graded material sections on the basis of a hybrid finite element
approach. A hybrid finite element based on a Hellinger-Reissner functional is
presented. A set of numerical examples is solved to verify the proposed method,
and a parametrical study is also performed.
KeyWords Plus: NONUNIFORM TORSION; BEAM THEORY; PLATES; BARS; RIGIDITY; ANALOGIES
Addresses: Istanbul Tech Univ, Dept Civil Engn, TR-34469 Istanbul, Turkey
E-mail Address: girgink@itu.edu.tr
Publisher: SPRINGER WIEN, SACHSENPLATZ 4-6, PO BOX 89, A-1201 WIEN, AUSTRIA
Subject Category: Engineering, Civil
IDS Number: FZ0RL
ISSN : 0001-5970
eISSN: 1619-6937
Title: Simplified formulations for the determination of rotational spring
constants in rigid spread footings resting on tensionless soil
Author(s): Girgin K.
Source : JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT, Vol. 23 (4), pp.464-474, 2017
Document Type: Article
Language: English
Accession Number: WOS:000400002400004
DOI: 10.3846/13923730.2016.1210218
Abstract: In spread footings, the rotational spring constants, which represent
the soil-structure interaction, play an important role in the structural
analysis and design. To assign the behaviour of soil, which is generally
represented via Winkler-type tensionless springs, necessitates time consuming
iterative computing procedures in practice. In this study, a straightforward
approach is proposed for the soil-structure interaction of rigid spread
footings especially subjected to excessive eccentric loading. By considering
the uplift of footing, the rotational spring constants of those type footings
under axial load and biaxial bending are easily attained through the proposed
simplified formulations. Since these formulations enable manual calculation,
iterative computer efforts are not required. The formulations under
consideration can be applicable to symmetric and non-symmetric rigid spread
footings. The numerical results of this study are verified with SAP2000.
Author Keywords: spread footing; rotational spring constant; tensionless Winkler-type
soil; axial load; bending; biaxial bending; soil-structure interaction
KeyWords Plus: ELASTIC FOUNDATIONS; NUMERICAL-METHOD; AXIAL LOAD; STIFFNESS
Addresses: Istanbul Tech Univ, Dept Civil Engn, TR-34469 Istanbul, Turkey
E-mail Address: girgink@itu.edu.tr
Publisher: VILNIUS GEDIMINAS TECH UNIV, SAULETEKIO AL 11, VILNIUS, LT-10223, LITHUANIA
Subject Category: Engineering, Civil
IDS Number: ET1CB
ISSN: 1392-3730
Title: A Design-Oriented Combined Model (7 MPa to 190 MPa) for FRP-Confined
Circular Short Columns
Author(s): Girgin Z.C., Girgin K.
Source : Polymers, Vol. 7 (10), pp.1905-1917, 2015
Document Type: Article
Language: English
Accession Number: WOS:000364289200001
DOI: 10.3390/polym7101489
Abstract: This study addresses a design oriented combined model to predict the
ultimate strengths and ultimate strains in an extensive range of unconfined
strength (7 to 190 MPa) for the axially loaded fiber-reinforced polymer
(FRP)-wrapped circular short columns. Modified Hoek-Brown strength criterion,
which was previously extended to FRP-confined concrete from 7 to 108 MPa, is
revisited and verified. An empirical strength model beyond 108 MPa encompassing
ultra-high strength concrete (UHSC) and ultra-high performance concrete (UHPC)
data, as well as empirical strain models, are defined to accomplish the design
oriented combined model. This article especially focuses on the verification of
the proposed strain models. The assessment performances of those models for
carbon FRP (CFRP) and glass FRP (GFRP) confinement are compared with specific
models in the current literature. Strength and strain predictions for UHSC and
UHPC are integrated into the design oriented combined model as well. The
assessments on this model agree with the experimental results in high accuracy.
Author Keywords: confined concrete; FRP; strength; strain; design oriented model;
Hoek-Brown; UHSC; UHPC
KeyWords Plus: STRESS-STRAIN MODEL; REINFORCED-CONCRETE COLUMNS; HIGH-STRENGTH CONCRETE;
AXIAL COMPRESSIVE BEHAVIOR; HIGH-PERFORMANCE CONCRETE; MECHANICAL-BEHAVIOR;
COMPOSITE JACKETS; FIBER COMPOSITES; RC COLUMNS; GFRP TUBES
Addresses: Yildiz Tekn Univ, Architecture Fac, Struct Syst Div, TR-34349 Istanbul,
Turkey
Istanbul Tech Univ, Dept Civil Engn, TR-34469 Istanbul, Turkey
E-mail Addresses: zcgirgin@yildiz.edu.tr; girgink@itu.edu.tr
Publisher: MDPI AG, POSTFACH, CH-4005 BASEL, SWITZERLAND
Subject Category: Polymer Science, Civil Engineering
IDS Number: CV5ED
ISSN: 2073-4360
Title: Research on the normality of the plastic strain vector to the yield surface in RC sections
Author(s): Girgin K., Girgin Z.C., Aksoylu M.G.
Source : Materials and Structures,Vol. 47, pp.1115–1130, 2014
Document Type: Article
Language: English
Accession Number: WOS:000336021300002
DOI: 10.1617/s11527-013-0116-3
Abstract: In this study, the normality condition of the plastic strain vector to the
yield surface utilized for elastic-perfectly plastic materials is investigated
for reinforced concrete (RC) sections. If the plastic strain vector can be
assumed outward normal to the yield surface in RC sections under combined
biaxial bending and axial load, the components of the vector can be expressed
by a single parameter. Thus, the material nonlinearity can be simplified
through the extended plastic hinge concept based on the normality condition. In
this study the normality of the plastic strain vector is verified via numerical
examples in symmetrically reinforced rectangular and circular RC sections
subjected to biaxial bending and axial load for various configurations of
longitudinal reinforcement.
Author Keywords: Reinforced concrete sections; Elastic-perfectly plastic material;
Yield surface; Plastic strain vector; Flow rule
KeyWords Plus: REINFORCED-CONCRETE SECTIONS; AXIAL FORCE; CROSS-SECTIONS; COMPOSITE;
COLUMNS; SUBJECT; DESIGN; LOADS; MODEL
Addresses: Istanbul Tech Univ, Dept Civil Engn, TR-34469 Istanbul, Turkey
E-mail Addresses: girgink@itu.edu.tr
Publisher: Springer Netherlands
Subject Category: Engineering, Civil
IDS Number: AH3KE
ISSN: 1359-5997
eISSN: 1871-6873
Title: A load increment method for ductile reinforced concrete (RC) frame structures considering strain hardening effects
Author(s): Aksoylu M. G., Girgin K.
Source: STRUCTURAL ENGINEERING AND MECHANICS Volume: 38 Issue: 2
Pages: 231-247 Published: APR 25 2011
Document Type: Article
Language: English
Accession Number: WOS:000288975700006
Abstract: This study introduces a new load increment method for the ductile
reinforced concrete (RC) frame structures by including strain-hardening
effects. The proposed method is a nonlinear static analysis technique employed
for RC frame structures subjected to constant gravity loads and monotonically
increasing lateral loads. The material nonlinearity in RC structural elements
is considered by adopting plastic hinge concept which is extended by including
the strain hardening as well as interaction between bending moment and axial
force. Geometric non-linearity, known as second order effect, is implemented to
the method as well.
Author Keywords: RC frames; strain-hardening; load increment method; seismic
evaluation; non-linear static analysis; second-order effect
KeyWords Plus: PLASTIC-HINGE ANALYSIS; PUSHOVER ANALYSIS; STATIC PUSHOVER; BUILDINGS
Addresses: Istanbul Tech Univ, Dept Civil Engn, TR-34469 Istanbul, Turkey
E-mail Addresses: aksoylug@itu.edu.tr
Publisher: Istanbul Technical University, Istanbul, 34469, Turkey
Subject Category: Engineering, Civil
IDS Number: 742WJ
ISSN: 1225-4568
Title: Performance evaluation of a strengthened building considering the soil-structure interaction
Author(s): Orakdogen, E., Girgin, K., Boduroglu, M.H., Buyuksisli, B., Gokce, T.
Source: Journal of Earthquake Engineering, pp.222-233, Vol.12, Issue S2, January 1,
2008.
Document Type: Article
Language: English
Accession Number: WOS:000257104500022
DOI: 10.1080/13632460802014097
Abstract: In this article, performance evaluations of a 3D building
strengthened by additional shear-walls are presented as a case study by
considering the foundation effects. Soil-structure interaction is included in
the nonlinear static analysis of the building and performance evaluations are
made according to Chs. 6 and 8 of FEMA440. Different foundation types such as
mat foundation, continuous or single footings are considered in the analysis.
Tensionless elastic-plastic Winkler soil model is used for soil behavior.
Non-linear push-over analysis and performance evaluations are obtained by
SAP2000 computer package. Elastic-plastic Winkler soil behavior is represented
by equivalent frame elements subjected only to axial forces and equivalent
axial stiffness is defined for these elements. Mat foundation and footings are
idealized as linear-elastic thick shell elements in the analysis. Performance
evaluations and comparisons for the strengthened building are given in detail
for different foundation types.
Author Keywords:Performance-Based Design; Soil-Structure Interaction; Nonlinear Static
Analysis; Seismic Safety
Addresses: Orakdogen, E (reprint author), Istanbul Tech Univ, Fac Civil Engn,
TR-34469 Istanbul, Turkey
E-mail Addresses: orak@itu.edu.tr
Publisher: TAYLOR & FRANCIS LTD, 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN,
OXON, ENGLAND
Subject Category: Engineering, Geological; Geosciences,
Multidisciplinary
IDS Number: 318PQ
ISSN: 1363-2469 print/ 1559-808X online
DOI: 10.1080/13632460802014097
Title: Effective lengths of braced frame columns
Author(s): Girgin K (Girgin, Konuralp), Ozmen G (Ozmen, Gunay)
Source: STRUCTURAL ENGINEERING AND MECHANICS Volume: 28 Issue: 2
Pages: 189-206 Published: 2008
Document Type: Article
Language: English
Accession Number: WOS:000252287500004
Abstract: In several design codes and specifications, simplified formulae and
charts are given for determining the effective lengths of frame columns. It is
shown that these formulae may yield rather erroneous results in certain cases.
This is due to the fact that, the code formulae utilise only local stiffness
distributions. In this paper, a simplified procedure for determining
approximate values for the buckling loads of braced frames is developed. The
procedure utilises a fictitious load analysis of frames and yields errors less
than 10%, which may be considered suitable for design purposes. The proposed
procedure is applied to several numerical examples and it is shown that all the
errors are in the acceptable range.
Author Keywords: buckling load; buckling length; effective length; non-sway mode;
braced frames; isolated subassembly; multi-storey frames; design codes
KeyWords Plus: UNBRACED FRAMES; STABILITY
Addresses: Girgin, K (reprint author), Istanbul Tech Univ, Fac Civil Engn, TR-34469
Istanbul, Turkey
E-mail Addresses: kgirgin@ins.itu.edu.tr, gunayozmen@hotmail.com
Publisher: TECHNO-PRESS, PO BOX 33, YUSEONG, DAEJEON 305-600, SOUTH KOREA
Subject Category: Engineering, Civil; Engineering, Mechanical
IDS Number: 250GH
ISSN: 1225-4568
Title: A simplified solution of the torsional rigidity of the composite beams by using FEM
Author(s): Saygun A (Saygun, A.), Ormurtag MH (Ormurtag, M. H.), Orakdogen E
(Orakdogen, E.), Girgin K (Girgin, K.), Kucukarslan S (Kucukarslan, S.),
Darilmaz K (Darilmaz, K.)
Source: ADVANCES IN STRUCTURAL ENGINEERING 10 (5): 467-473 OCT 2007
Document Type: Article
Language: English
Accession Number: WOS:000250668200001
DOI: 10.1260/136943307782417726
Abstract: In this paper, the torsional rigidity of the composite sections formed by
different materials is obtained by using a finite element procedure. In the
derivation of the differential equation, the Saint-Venant's stress function was
used. The obtained partial differential equation was discretized by finite
elements to get the potentials in the nodal points. After the calculations of
the unknown potentials on the composite cross-section, the torsional rigidity
is calculated by integrating the potentials on the solution domain. To test the
validity of the proposed algorithm, the available analytical and numerical
results from the previous studies were studied. It was seen that this new
algorithm is efficient and simpler than the previous ones.
Author Keywords: torsional rigidity; Saint-Venant's stress function; finite element
method; numerical analysis; composite beam
Address: Girgin K (reprint author), Istanbul Tech Univ, Fac Civil Engn,
TR-34469 Istanbul, Turkey
E-mail Address: girgink@itu.edu.tr
Publisher: MULTI SCIENCE PUBL CO LTD, 5 WATES WAY, BRENTWOOD CM15 9TB, ESSEX,
ENGLAND
Subject Category: Construction & Building Technology;
Engineering, Civil
IDS Number: 227OT
ISSN: 1369-4332
Title: Simplified procedure for determining buckling loads of three-dimensional framed structures
Author(s): Girgin K (Girgin, Konuralp), Ozmen G (Ozmen, Gunay)
Source: ENGINEERING STRUCTURES 29 (9): 2344-2352 SEP 2007
Document Type: Article
Language: English
Accession Number: WOS:000249272400030
DOI: 10.1016/j.engstruct.2006.11.026
Abstract: A simplified procedure for determining approximate values for the
buckling loads of three-dimensional framed structures is developed. The
procedure utilises lateral load analysis of structures and yields error-, less
than 10%, which may be considered suitable for design purposes. The structures
with or without rigid floor diaphragms may be considered readily. Bucklin.-
loads of both regular and irregular structures may be obtained. The proposed
procedure is applied to several numerical examples and it is shown that all the
errors are in the acceptable range and generally on the safe side. Determining
the buckling loads of structures using SAP2000 is also discussed.
Author Keywords: buckling load; buckling modes; isolated subassembly; rigid floor
diaphragms; irregular structures; SAP2000 applications
KeyWords Plus: STABILITY
E-mail Address: girgink@itu.edu.tr
Publisher: ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD
OX5 1GB, OXON, ENGLAND
Subject Category: Engineering, Civil
IDS Number: 207SW
ISSN: 0141-0296
Title: Torsional rigidity of arbitrarily shaped composite sections by hybrid finite element approach
Author(s): Darilmaz K (Darilmaz, Kutlu), Orakdogen E (Orakdogen, Engin), Girgin K
(Girgin, Konuralp), Kucukarslan S (Kucukarslan, Semih)
Source: STEEL AND COMPOSITE STRUCTURES 7 (3): 241-251 JUN 2007
Document Type: Article
Language: English
Accession Number: WOS:000247658800004
Abstract: The purpose of this study is to calculate the torsional rigidity of
arbitrarily shaped composite sections on the basis of hybrid finite element
approach. An analogy is used between the torsion problem and deformation of a
plate which exhibits only shear behavior. In the analysis a simple hybrid
finite element based on Hellinger-Reissner functional is presented and a set of
numerical examples are performed to demonstrate and asses the performance of
the developed element in practical applications.
Author Keywords: torsional rigidity; Saint-Venant's stress function; plate;
hybrid finite element
KeyWords Plus: FREE-VIBRATION ANALYSIS; BEAM THEORY; BARS
Address: Darilmaz K (reprint author), Tech Univ Istanbul, Fac Civil Engn,
TR-34469 Istanbul, Turkey
E-mail Address: darilmazk@itu.edu.tr
Publisher: TECHNO-PRESS, PO BOX 33, YUSEONG, DAEJEON 305-600, SOUTH KOREA
Subject Category: Construction & Building Technology;
Engineering, Civil; Materials Science, Composites
IDS Number: 184RG
ISSN: 1229-9367
Title: Free vibration analysis of non-cylindrical helices with variable cross-section by using mixed FEM
Author: Girgin K (Girgin, Konuralp)
Source: JOURNAL OF SOUND AND VIBRATION 297 (3-5): 931-945 NOV 6 2006
Document Type: Article
Language: English
Accession Number: WOS:000240768900030
DOI: 10.1016/j.jsv.05.001
Abstract: The objective of the study is to present a mixed finite element (FE)
formulation for the free vibration analysis of non-cylindrical helices with
variable cross-section. Non-cylindrical helix geometry was well approximated
through the variable arc lengths and linear variations in curvatures via shape
functions. The mixed FE model for non-cylindrical helices was developed by
using the exact cylindrical helix geometry and corresponding field equations.
The element and consistent mass matrices are attained under these assumptions.
The element matrix is derived based on the Timoshenko beam theory and the
effects of rotary inertia are involved into the mass matrix. Although the
formulation is quite simple, the generated element is capable to provide highly
accurate solutions for the conical, barrel and hyperboloidal geometries of
non-cylindrical helices. The results of presented FE model based on an
approximated geometry approach are in a good agreement with the other studies
in the actual literature. Some original examples were generated and solved for
the literature as well.
KeyWords Plus: NATURAL FREQUENCIES; ARBITRARY SHAPE; FINITE-ELEMENTS; COIL SPRINGS;
FORMULATION; BEAMS; MODEL; BARS; RODS
Address: Girgin K (reprint author), Tech Univ Istanbul, Fac Civil Engn, TR-34469
Istanbul, Turkey
E-mail Address: girgink@itu.edu.tr
Publisher: ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD, 24-28 OVAL RD, LONDON NW1 7DX,
ENGLAND
Subject Category: Acoustics; Engineering, Mechanical; Mechanics
IDS Number: 087UT
ISSN: 0022-460X
Title: A numerical method for static and free-vibration analysis of non-uniform Timoshenko beam-columns
Author(s): Girgin ZC, Girgin K
Source: CANADIAN JOURNAL OF CIVIL ENGINEERING 33 (3): 278-293 MAR 2006
Document Type: Article
Language: English
Accession Number: WOS:000238258600008
DOI: 10.1139/L05-109
Abstract: A generalized numerical method is proposed to derive the static and dynamic
stiffness matrices and to handle the nodal load vector for static analysis of
non-uniform Timoshenko beam-columns under several effects. T his method
presents a unified approach based,on effective utilization of the Mohr method
and focuses on the following arbitrarily variable characteristics: geometrical
properties, bending and shear deformations, transverse and rotatory inertia of
mass, distributed and (or) concentrated axial and (or) transverse loads, and
Winkler foundation modulus and shear foundation modulus. A successive iterative
algorithm is developed to comprise-all these characteristics systematically.
The algorithm enables a non-uniform Timoshenko beam-column to be regarded as a
substructure. This provides an important advantage to incorporate all the
variable characteristics based on the substructure. The buckling load and
fundamental natural frequency of a substructure subjected to the cited effects
are also assessed. Numerical examples confirm the efficiency of the numerical
method.
Author Keywords: non-uniform; Timoshenko; substructure; elastic
foundation; geometrical nonlinearity; stiffness; stability; free
vibration
KeyWords Plus: DYNAMIC-STIFFNESS MATRIX; 2-PARAMETER ELASTIC FOUNDATIONS; TRANSVERSE
VIBRATIONS; FINITE-ELEMENT; CROSS-SECTION; SHEAR; FORMULATION; FREQUENCIES;
RANGE; MEDIA
Addresses: Girgin ZC (reprint author), Yildiz Tech Univ, Architectural Fac, Struct
Syst Dept, TR-34349 Istanbul, Turkey
Istanbul Tech Univ, Dept Civil Engn, TR-34469 Istanbul, Turkey
E-mail Address: canan.girgin@gmail.com
Publisher: NATL RESEARCH COUNCIL CANADA, RESEARCH JOURNALS, MONTREAL RD, OTTAWA,
ONTARIO K1A 0R6, CANADA
Subject Category: Engineering, Civil
IDS Number: 052UE
ISSN: 0315-1468
Title: Buckling lengths of irregular frame columns
Author(s): Girgin K, Ozmen G, Orakdogen E
Source: JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH 62 (6): 605-613
JUN 2006
Document Type: Article
Language: English
Accession Number: WOS:000236567400008
DOI: 10.1016/j.jcsr.2005.09.006
Abstract: In several design codes and specifications, simplified formulae and
diagrams are given for determining the buckling lengths of frame columns. It is
shown that these formulae may yield rather erroneous results, especially for
irregular frames. This is due to the fact that the code formulae utilise only
local stiffness distributions. In this paper, a simplified procedure for
determining approximate values for the buckling loads of both regular and
irregular frames is developed, The procedure utilises lateral load analysis of
frames and yields errors on the order of 5%, which may be considered suitable for
design purposes. The proposed procedure is applied to several numerical
examples and it is shown that all the errors are in the acceptable range and on
the safe side.
Author Keywords: buckling load; buckling length; effective length; sway
mode; unbraced frames; irregular frames; isolated subassembly; design codes
KeyWords Plus: UNBRACED FRAMES; 2ND-ORDER ANALYSIS; STABILITY
Address: Girgin K (reprint author), Istanbul Tech Univ, Fac Civil Engn,
TR-34469 Istanbul, Turkey
E-mail Address: girgink@itu.edu.tr
Publisher: ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD
OX5 1GB, OXON, ENGLAND
Subject Category: Construction & Building Technology;
Engineering, Civil
IDS Number: 029MO
ISSN: 0143-974X
Title: A numerical method for static or dynamic stiffness matrix of non-uniform members resting on variable elastic foundations
Author(s): Girgin ZC, Girgin K
Source: ENGINEERING STRUCTURES 27 (9): 1373-1384 AUG 2005
Document Type: Article
Language: English
Accession Number: WOS:000230383300007
DOI: 10.1016/j.engstruct.2005.04.005
Abstract: This paper presents a generalized numerical method which is based on
the well-known Mohr method. Static or dynamic stiffness matrices, as well as
nodal load vectors for the static case, of non-uniform members are derived for
several effects. The method focuses on the effects of resting on variable one-
or two-parameter elastic foundations or supported by no foundation; a variable
iterative algorithm is developed for computer application of the method. The
algorithm enables the non-uniform member to be regarded as a sub-structure.
This provides an important advantage to encompass all the variable effects in
the stiffness matrix of this sub-structure. Stability and free-vibration
analyses of the sub-structure can also be carried out through this method. Parametric
and numerical examples are given to verify the accuracy and efficiency of the
submitted method.
Author Keywords: non-uniform member; arbitrarily variable; two-parameter
elastic foundation; geometric non-linearity; stiffness matrix; stability and
free-vibration analysis
KeyWords Plus: VIBRATION ANALYSIS; FINITE-ELEMENT; TAPERED BEAMS;
FREQUENCIES; STABILITY; SECTION
Addresses: Girgin ZC (reprint author), Yapi Merkezi Construct Inc, TR-34676 Istanbul,
Turkey
Tech Univ Istanbul, Dept Civil Engn, TR-34469 Istanbul, Turkey
E-mail Addresses: canan.girgin@gmail.com
Publisher: ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD
OX5 1GB, OXON, ENGLAND
Subject Category: Engineering, Civil
IDS Number: 943VQ
ISSN: 0141-0296
Title: Direct determination of influence lines and surfaces by FEM
Author(s): Orakdogen E, Girgin K
Source: STRUCTURAL ENGINEERING AND MECHANICS 20 (3): 279-292 JUN 20
2005
Document Type: Article
Language: English
Accession Number: WOS:000231787600002
Abstract: In this study, element loading matrices are defined for static
application of classical Muller-Breslau principle to finite element method. The
loading matrices are derived from existing element matrices using Betti's law
and known governing equations of F.E.M. Thus, the ordinates of influence lines
and influence surfaces may be easily obtained from structural analysis for the
loading matrices derived from governing equations, instead of through
introduced unit force or displacement techniques. An algorithm for a computer
program and comparative numerical examples are also presented to illustrate the
procedure for determination of influence line and surface ordinates.
Author Keywords: influence lines; influence surfaces; Betti's law; Muller-Breslau
principle; finite element method
Addresses: Orakdogen E (reprint author), Istanbul Tech Univ, Fac Civil Engn,
TR-34469 Istanbul, Turkey
Istanbul Tech Univ, Fac Civil Engn, TR-34469 Istanbul, Turkey
E-mail Address: orak@itu.edu.tr
Publisher: TECHNO-PRESS, PO BOX 33, YUSEONG, DAEJEON 305-600, SOUTH KOREA
Subject Category: Engineering, Civil; Engineering, Mechanical
IDS Number: 963EY
ISSN: 1225-4568
Title: Buckling lengths of unbraced multi-storey frame columns
Author(s): Ozmen G, Girgin K
Source: STRUCTURAL ENGINEERING AND MECHANICS 19 (1): 55-71 JAN 10
2005
Document Type: Article
Language: English
Accession Number: WOS:000225555300004
Abstract: In several design codes and specifications, simplified formulae and
diagrams are given for determining the buckling lengths of frame columns. It is
shown that these formulae may yield rather erroneous results in certain cases.
This is due to the fact that, the code formulae utilise only local stiffness
distributions. In this paper, a simplified procedure for determining
approximate values for the buckling loads of multi-storey frames is developed.
The procedure utilises lateral load analysis of frames and yields errors in the
order of 10%, which may be considered suitable for design purposes. The
proposed procedure is applied to several numerical examples and it is shown
that all the errors are in the acceptable range and on the safe side.
Author Keywords: buckling load; buckling length; effective
length; sway mode; unbraced frames; isolated subassembly; multi-storey frames;
design codes
KeyWords Plus: 2ND-ORDER ANALYSIS; STABILITY
Addresses: Ozmen G (reprint author), Tech Univ Istanbul, Fac Civil Engn, TR-34469 Istanbul,
Turkey
Tech Univ Istanbul, Fac Civil Engn, TR-34469 Istanbul, Turkey
Publisher: TECHNO-PRESS, PO BOX 33, YUSEONG, DAEJEON 305-600, SOUTH KOREA
Subject Category: Engineering, Civil; Engineering,
Mechanical
IDS Number: 877GG
ISSN: 1225-4568
Title: Seismic response of infilled framed buildings using pushover analysis
Author(s): Girgin K, Darilmaz K
Source: ARI Bulletin of the Istanbul Technical University, Volume: 54 Issue: 5
Pages: 1-17 July 2007.
Document Type: Article
Language: English
Abstract: Structural frames are often filled with infilled walls serving as
partitions. Although the infills usually are not considered in the structural
analysis and design, their influence on the seismic behaviour of the infilled
frame structures is considerable. In the present study, a parametric study of
certain infilled frames, using the strut model to capture the global effects of
the infills was carried out. Three concrete planar frames of five-stories and
three-bays are considered which have been designed in accordance with Turkish
Codes. Pushover analysis is adopted for the evaluation of the seismic response
of the frames. Each frame is subjected to four different loading cases. The
results of the cases are briefly presented and compared. The effect of infill
walls on seismic behavior of two sample frames with different infill
arrangements was investigated. The results yield that it is essential to
consider the effect of masonry infills for the seismic evaluation of
moment-resisting RC frames, especially for the prediction of its ultimate
state, infills having no irregularity in elevation have beneficial effect on
buildings and infills appear to have a significant effect on the reduction of
global lateral displacements.
Author Keywords: infilled frame; pushover analysis; infill walls; seismic response; capacity
spectrum; plastic hinge
Address: Girgin K (reprint author), Istanbul Tech Univ, Fac Civil Engn,
TR-34469 Istanbul, Turkey
E-mail Address: girgink@itu.edu.tr
Publisher: Istanbul Technical University, Istanbul, 34469, Turkey
Subject Category: Engineering, Civil
ISSN: 1434-5641
Title: Torsional irregularity in multi-storey structures
Author(s): Özmen, G., Girgin K., Durgun, Y.
Source: International Journal of Advanced Structural Engineering, 17 September, 2014,
DOI 10.1007/s40091-014-0070-5
Document Type: Article
Language: English
Abstract: The purpose of this study is first to determine the conditions for
excessive torsional irregularity and then to discuss the validity of code
provisions. A parametric investigation is performed on six groups of typical
structures with varying shear wall positions, story and axis numbers. It is
found that torsional irregularity coefficients increase as the story numbers
decrease, i.e. maximum irregularity coefficients occur for single-story
structures. They reach maximum values when the asymmetrical shear walls are
placed as close as possible to the centers of mass. However, the results
obtained for floor rotations are quite contradictory. A new provisional
definition for torsional irregularity coefficient based on floor rotations is
proposed.
Author Keywords: Earthquake regulations; Torsional irregularity ; Parametric
investigation ; Floor rotations
Addresses: Istanbul Tech Univ, Dept Civil Engn, TR-34469 Istanbul, Turkey
E-mail Address: girgink@itu.edu.tr
Publisher: Springer Berlin Heidelberg
Subject Category: Engineering, Civil
ISSN: 2008-3556 (print version)
eISSN: 2008-6695 (electronic version)