Conceptual Structural Design of High-Rise Buildings with Wind Alterations

182 Pages·2017·25 MB·English

by  Elise Hverven

Conceptual Structural Design of High-
Rise Buildings with Wind Alterations
Elise Hverven
Civil and Environmental Engineering
Submission date: June 2017
Supervisor: Anders Rönnquist, KT
Norwegian University of Science and Technology
Department of Structural Engineering

ACCESSIBILITY

OPEN
Department of Structural Engineering
Faculty of Engineering Science and Technology
NTNU- Norwegian University of Science and Technology

MASTER THESIS 2017

SUBJECT AREA: DATE: NO. OF PAGES:
Structural Design June 8th 2017 96+60

TITLE:

Conceptual Structural Design of High-Rise Buildings with Wind Alterations

Konseptuelt design av høyhus med tilpasninger for vind
BY:

Elise Myhre Hverven
SUMMARY:
The aim of this thesis is to develop a conceptual structural design for a tall building located in Oslo, Norway.
For a structural engineering student, it is vital to reflect on how the structural system can enhance the
architectural expression of the building. When a skyscraper is situated in Oslo, the governing load is wind.
When adding alterations to a basic configuration, the building can be optimized structurally to withstand wind
induced pressure, this also adds a unique architectonic expression of the building. Basic geometrical shapes,
both with and without alterations, have been analyzed in computer software wind tunnel testing. As a result,
the plan geometry and modifications over the vertical height are optimized for uniform wind loads. Due to the
results from the wind tunnel testing, the hexagonal and octagonal models were further analyzed in the
computer program ETABS. All together there were six models; the basic geometries, models with twisting
over the vertical height, and models with tapering and twisting over the vertical height. In ETABS the models
were exposed to earthquake and wind loads according to given National Standards. Consequently, the
stiffness and flexibility of the structures under these loads was evaluated. Results from the computational
program and further manually calculated results, have been compared to Norwegian thresholds within
serviceability of structures. From the analysis results, it is possible to conclude that the additional examined
alterations will enhance the buildings performance under wind loads. The displacements are reduced, as well
as the over-all volume of the load-resisting structure. The acceleration of the structures under wind loads are
roughly equivalent for all the models. Consequently, twisting and tapering over the vertical height, as well as
a reduced volume of the load-bearing structure, does not reduce the global stiffness of the structures.

RESPONSIBLE TEACHER: Prof. Nils Erik Anders Rønnquist

SUPERVISOR: Prof. Nils Erik Anders Rønnquist

CARRIED OUT AT: Department of Structural Engineering (NTNU)

ABSTRACT
Throughout the past seventy years, the skyscraper’s evolution has evolved due to
thecloserelationshipandcooperationbetweenarchitects, engineers, andtechnology.
This partnership has led to a field where the architectural expression is directly
linked to the structural performance and structural design of high-rise buildings.
The aim of this thesis is to develop a conceptual structural design for a tall building
locatedinOslo, Norway. Forastructuralengineeringstudent, itisthereforevitalto
reflect on how the structural system can enhance the architectural expression of the
building. When a skyscraper is situated in Oslo, the governing load is wind. When
addingalterationstoabasicconfiguration,thebuildingcanbeoptimizedstructurally
towithstandwindinducedpressure,thisalsoaddsauniquearchitectonicexpression
of the building.
Basic geometrical shapes, both with and without alterations, have been analyzed
in computer software wind tunnel testing. As a result, the plan geometry and
modifications over the vertical height are optimized for uniform wind loads. Due
to the results from the wind tunnel testing, the hexagonal and octagonal models
were further analyzed in the computer program ETABS. All together there were
six models; the basic geometries, models with twisting over the vertical height,
and models with tapering and twisting over the vertical height. In ETABS the
models were exposed to earthquake and wind loads according to given National
Standards. Consequently, the stiffness and flexibility of the structures under these
loadswasevaluated. Resultsfromthecomputationalprogramandfurthermanually
calculatedresults,havebeencomparedtoNorwegianthresholdswithinserviceability
of structures.
From the analysis results, it is possible to conclude that the additional examined
alterations will enhance the buildings performance under wind loads. The displace-
ments due to wind and seismic loads are reduced, as well as the over-all volume of
the load-resisting structure. The acceleration of the structures under wind loads
are roughly equivalent for all the models. Consequently, twisting and tapering over
the vertical height, as well as a reduced volume of the load-bearing structure, doe
not reduce the global stiffness of the structures.
I

SAMMENDRAG
Skyskrapere har gjennomg˚att en rivende utvikling de siste sytti˚arene grunnet det
tette samarbeidet mellom arkitekter, ingeniører og ny teknologi. Dette har ledet til
atdetarkitektoniskedesignetern˚adirektekoblettildenstrukturellekonstruksjonen
av bygget.
Form˚alet med denne masteroppgaven er˚a utvikle et konseptuelt designet høyhus i
Oslo, Norge. For en student med spesialisering innenfor konstruksjonsteknologi er
detderforviktig˚afokuserep˚ahvordankonstruksjonenkanoptimaliserestil˚amotst˚a
lastene, men samtidig oppn˚a et unikt arkitektonisk uttrykk. N˚ar en skyskraper er
lokalisert i Oslo, er vind den dominerende lasten. Ved˚a modifisere bygget over den
vertikale høyden, kan konstruksjonen optimaliseres med tanke p˚a vindlaster. Dette
vil igjen ha en positiv innvirkning p˚a det arkitektoniske designet.
Grunnleggende geometriske former, b˚ade med og uten modifikasjoner, har blitt
analysertiprogramvare-generertevindtunneler. Disseresultatenedannergrunnlaget
for valg og optimalisering av modellene. De som fikk best resultater fra vindtunnel-
testen hadde heksagonale og oktagonale grunnformer. Formene ble videre analysert
i modelleringsprogrammet ETABS. Alt i alt var det seks modeller; de to basis
geometriene, modeller med rotasjon over den vertikale høyden, og modeller med
rotasjon og avtrapping over den vertikale høyden. I programmet ETABS ble model-
lene eksponert for jordskjelvs- og vindlaster i henhold til de norske standardene.
Resultatene fra programmet og videre manuelle kalkulasjoner ble kontrollert opp
mot nasjonale bruksgrenser.
Resultateneviseratmodifikasjoneroverdenvertikalehøydenforbedrerbygningenes
evne til˚a t˚ale vind. De horisontale forskyvningene fra vind- og jordskjelvslaster
er redusert, p˚a tross av at volumet av den lastbærende konstruksjonen er minsket.
Akselerasjonene under ekstreme vindforhold er sammenlignbare for alle modellene.
Konklusjonen er at rotasjon og avtrapping over den vertikale høyden, samt redusert
volum av den lastbærende konstruksjonen, ikke fører til en redusert stivhet av
konstruksjonene.
III

ACKNOWLEDGMENT
This is a Master thesis belonging to the Department of Structural Engineering at
The Norwegian University of Science and Technology, NTNU. The thesis is within
Structural Design and Engineering Architecture, with the aim to reflect and study
both of these fields. The topic and context is designed by the student with the help
of Prof. Nils Erik Anders Rønnquist; the main supervisor, to be able to create an
unconventional topic of investigation.
Articles, books, National Standards and technical reports have been used as guide-
lines and supporting literature for the decision making process and analysis results.
The calculations are mainly calculated by following the Norwegian restrictions;
found in the Eurocodes, supporting National Annex, and ISO-standards. For the
conceptual design portion of the thesis, supporting literature has been used to
obtain the desired structural and architectonic design.
ETABS, Autodesk Revit, Autodesk Flow Design, and Rhinoceros with the plugin
Ladybug, are the supporting software programs that have been used to achieve the
model designs and results for wind and seismic design analysis of the structure.
The student had the unique opportunity to spendtwo semesters abroad at Nanyang
Technological University, NTU, in Singapore. Singapore’s skyline is filled with
prominent skyscrapers, and they have some of the most exceptional designs. The
Student’sparticipationinthecourseCV6108: AnalysisandDesignofTallBuildings
atNTU,ledtoaninterestandbasicknowledgewithinthefieldofskyscrapers. This
paved the way for the topic of the thesis.
I would like to direct thank my supervisor, Prof. Nils Erik Anders Rønnquist.
Guidance, humor, and a critical eye from Prof. Rønnquist was highly necessary
throughout these past months. The co-workers at EDRMedeso have also been a
tremendous help, with being able to grant the student with a license for ETABS.
Trondheim, June 8th 2017
Elise Myhre Hverven
V