Table Of ContentInvestigation of RC Structural Behaviour
of Wall-Equivalent Dual System through
Non-Linear Analyses.
Undersøkelse av den konstruksjonsmessige
oppførselen til veggekvivalent dobbeltsystem
i armert betong ved hjelp av ikke-lineære
analyser
Samson Amanuel Semere
Master of Science in Civil and Environmental Engineering
Submission date: June 2016
Supervisor: Amir Kaynia, KT
Norwegian University of Science and Technology
Department of Structural Engineering
Investigation of RC Structural Behaviour
of Wall-Equivalent Dual System
through Non-Linear Analyses.
Samson Amanuel Semere
Civil and Environmental Engineering
Submission date: June 2015
Supervisor: Professor II Amir Kaynia, NTNU
Co-supervisor: Nina Øystad-Larsen, Ramboll
Norwegian University of Science and Technology
Department of Structural Engineering
Department of Structural Engineering ACCESSIBILITY
Faculty of Engineering Science and Technology
Open
NTNU- Norwegian University of Science and Technology
MASTER THESIS 2016
SUBJECT AREA: DATE: NO. OF PAGES: 139
Structural dynamics 10 June 2015 (18+80+41)
TITLE:
Investigation of RC Structural Behaviour of Wall-Equivalent Dual System
through Non-Linear Analyses.
Undersøkelse av den konstruksjonsmessige oppførselen til veggekvivalent
dobbeltsystem i armert betong ved hjelp av ikke-lineære analyser.
BY:
Samson Amanuel Semere
SUMMARY:
The purpose of this thesis is to evaluate the non-linear response of a wall-equivalent
dual-system structure. The procedure of the analyses follows the guidelines incorporated
in the current Norwegian seismic design code NS-EN 1998-1. The investigated structure
is detailed for medium ductility in accordance to NS-EN 1998-1. A representative finite
element model of the structure (2D) is created with SeismoStruct and OpenSees
software packages with emphasis on capturing the non-linear behavior adequately. Both
non-linear static analysis and non-linear time history analysis are executed to simulate
earthquake for the structure in question.
Over-strength and period-based ductility factors of the structure are assessed in
accordance to FEMA P695 and the results confirmed that a conservative approach is
incorporated in NS-EN 1998-1. Although the structure is detailed for DCM, the results
from non-linear static analysis revealed that the structure response remained in the
elastic range. Furthermore, in the latter analysis the software packages give excellent
results in terms of target displacements and base shear forces. Non-linear time history
analysis confirmed the results obtained from non-linear static analysis for displacements.
Moreover, the importance of distribution of stiffness through the structure with regard to
inter-storey drifts is demonstrated. The effect of a soft storey is investigated by increasing
the height of the first floor. The results reveal that the inter-storey drifts highly increases
at the lower stories rather than at the upper stories.
RESPONSIBLE TEACHER: Professor II Amir Kaynia.
SUPERVISORS: Professor II Amir Kaynia, Nina Øystad-Larsen.
CARRIED OUT AT: Department of Structural Engineering.
Preface
ThismasterthesisiswrittenattheDepartmentofStructuralEngineering,NorwegianUniversity
of Science and Technology (NTNU) in collaboration with Rambøll Norway (Oslo). The thesis
accounts 30 credit points and is conducted during the spring semester of 2016. The topic
of this thesis is ” Investigation of RC Structural Behaviour of Wall-Equivalent Dual System
through Non-Linear Analyses ”. It is the authors interest to investigate structural behaviour
withPerformance-BasedSeismicDesign,whichisnotcoveredinthecurrentcurriculumofthe
structuralengineeringprogramatNTNU.
Onthisoccasion,IwouldliketothankmysupervisorProfessorIIAmirM.Kaynia(NTNU),for
sharinghisextensiveknowledgeintothetheoryofearthquakeanalysis,fortremendoussupport
and encouragement throughout the entire process. Additionally, I would like to thank my co-
supervisor PhD Candidate Nina Øystad-Larsen (Rambøll), for sharing her knowledge, for her
contributionsduringourcountlessmeetingsanddiscussionswhichhasbeenfundamentaltothe
follow-through and outcome of this master’s thesis. Last but not least , I want to thank my
familyandfriendsforbeinghelpfulandsupportive.
Trondheim,10. June2016
SamsonAmanuelSemere
Abstract
Since the introduction of NS-EN 1998-1, seismic design of structures have become a more
salienttopicinNorway. ThecodedividesstructuresintoclassesforDCH(ductilityclasshigh),
DCM (ductility class medium) and DCL (ductility class low). The ductility class is related to
the strength of the structure: the higher the ductility, the lower the design forces, and hence the
strength of the structure. DCM allows reduction of forces because of energy dissipation due to
plasticdeformation.
The purpose of this thesis is to evaluate the non-linear response of a wall-equivalent dual-
system structure. The procedure of the analyses follows the guidelines incorporated in the
current Norwegian seismic design code NS-EN 1998-1. The investigated structure is detailed
formediumductilityinaccordancetoNS-EN1998-1. Arepresentativefiniteelementmodelof
thestructure(2D)iscreatedwithSeismoStructandOpenSeessoftwarepackageswithemphasis
on capturing the non-linear behavior adequately. Both non-linear static analysis and non-linear
timehistoryanalysisareexecutedtosimulateearthquakeforthestructureinquestion.
Over-strength and period-based ductility factors of the structure are assessed in accordance
toFEMAP695andtheresultsconfirmedthataconservativeapproachisincorporatedinNS-EN
1998-1. Although the structure is detailed for DCM, the results from non-linear static analysis
revealed that the structure response remained in the elastic range. Furthermore, in the latter
analysis the software packages give excellent results in terms of target displacements and base
shear forces. Non-linear time history analysis confirmed the results obtained from non-linear
static analysis for displacements. Moreover, the importance of distribution of stiffness through
the structure with regard to inter-storey drifts is demonstrated. The effect of a soft storey is
investigated by increasing the height of the first floor. The results reveal that the inter-storey
driftshighlyincreasesatthelowerstoriesratherthanattheupperstories.
Keywords: Behaviourfactor,Wall-equivalentdualsystem,2Dseismicresponse,Over-strength,
OpenSees,SeismoStruct.
Description:Selv om konstruksjonen er dimensjonert for DCM, viser resultatene fra den ikke-lineære statiske analysen at den seismiske responsen forblir i det elastiske området. I tillegg gir den sistnevnte analysen fra programvarene utmerket resultater av påførte forskyvninger og skjærkrefter. Den ikke-li
