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Methodology for preliminary design of high-rise buildings

Svensson, Stefan LU and Castlen Rist, Viktor LU (2016) In TVSM-5000 VSM820 20161
Structural Mechanics
Department of Construction Sciences
Abstract
The construction of high-rise buildings has previously been limited in Sweden. Changes in society in recent years, related to urbanisation, economics and architectural standards have however resulted in a greater interest for the construction of high-rise buildings. When designing high-rise buildings, challenges are faced which often can be disregarded when designing lower buildings.

In this dissertation, a methodology which can be used in the preliminary design process of high-rise buildings is developed. The methodology is based on idealised calculation models and idealised finite element models, especially focused on the dynamical properties, natural frequencies and accelerations of the building. The report will describe how these... (More)
The construction of high-rise buildings has previously been limited in Sweden. Changes in society in recent years, related to urbanisation, economics and architectural standards have however resulted in a greater interest for the construction of high-rise buildings. When designing high-rise buildings, challenges are faced which often can be disregarded when designing lower buildings.

In this dissertation, a methodology which can be used in the preliminary design process of high-rise buildings is developed. The methodology is based on idealised calculation models and idealised finite element models, especially focused on the dynamical properties, natural frequencies and accelerations of the building. The report will describe how these calculations can be used to make the preliminary design of high-rise building and still obtain reasonable results. The work is focused on buildings with a structural system consisting of a concrete core with the possibility of adding outriggers. The dissertation also highlights the different phenomena related to high-rise buildings that needs to be considered in the preliminary stage, or later, in the design process. This includes, among other things, comfort requirements and wind induced accelerations. The stiffness is of great importance when designing high-rise buildings. For this reason, different ways to change the stiffness of the building are also analysed.

To evaluate how reliable the idealised calculations and models are, a case study on an ongoing project is performed. The calculations are performed on Gothenburg City Gate, a 120 meter tall building that is intended to be built in Gothenburg. The case study follows the methodology developed, in order to show an example of how the idealised models can be used in the preliminary design. The results of the idealised calculations are compared with the results of the finite element analysis to evaluate the accuracy of the calculations.

The analysis shows that an idealised beam model of the building with varying stiffness will give sufficient results for the preliminary design. Also the shape function provided by Eurocode can be used with good results. The idealised calculations of the natural frequencies gives results that correspond with the more advanced FE-models, the results differed 3-13% in the first modes. This is however only true for translation modes and torsional modes are not accurate. Adding an outrigger to the building drastically increased the first natural frequencies of the building, by up to 50% for Gothenburg City Gate. (Less)
Popular Abstract (Swedish)
Tidigare har byggandet av höga hus inte varit vanligt i Sverige, men på senare år har förändringar i samhället skett vilket lett till att höga hus blivit mer intressant. Vid dimensioneringen av höga hus uppkommer svårigheter och fenomen som inte behöver beaktas vid dimensioneringen av lägre hus.

I detta examensarbetet tas en arbetsmetodik fram, vilken kan följas vid den preliminära dimensioneringen av höga hus. Arbetsmetodiken baseras på idealiserade beräkningar och idealiserade FE-modeller och är framförallt inriktad på byggnadens dynamiska egenskaper, såsom egenfrekvenser och accelerationer. Arbetet beskriver hur dessa beräkningar kan användas vid den preliminära dimensioneringen av höga hus och fortfarande erhålla tillförlitliga... (More)
Tidigare har byggandet av höga hus inte varit vanligt i Sverige, men på senare år har förändringar i samhället skett vilket lett till att höga hus blivit mer intressant. Vid dimensioneringen av höga hus uppkommer svårigheter och fenomen som inte behöver beaktas vid dimensioneringen av lägre hus.

I detta examensarbetet tas en arbetsmetodik fram, vilken kan följas vid den preliminära dimensioneringen av höga hus. Arbetsmetodiken baseras på idealiserade beräkningar och idealiserade FE-modeller och är framförallt inriktad på byggnadens dynamiska egenskaper, såsom egenfrekvenser och accelerationer. Arbetet beskriver hur dessa beräkningar kan användas vid den preliminära dimensioneringen av höga hus och fortfarande erhålla tillförlitliga resultat. Uppsatsen belyser även de specifika problemen som behöver beaktas vid konstruktion av höga hus vid den preliminära dimensioneringen eller i ett senare stadie. Detta omfattar bland annat komfortkrav och vindinducerad acceleration. Styvheten av byggnaden är mycket viktig för höga hus. Av denna anledning diskuteras och analyseras olika metoder på hur byggnadens styvhet kan justeras.

För att utvärdera hur pålitliga de förenklade beräkningarna och modellerna är används dessa på ett pågående projekt, Göteborg City Gate, ett 120 meter högt hus som planeras att byggas i Göteborg. Fallstudien följer den framtagna arbetsmetodiken för att visa hur de förenklade modellerna kan användas vid den preliminära dimensioneringen. Resultat från de förenklade beräkningarna jämförs med resultat från finita element modeller för att utvärdera tillförlitligheten.

Analyserna visar att en enkel balkmodell med varierande styvhet kan användas för att erhålla resultat som går att använda i den preliminära dimensioneringen. Även formfunktionen som är angiven i Eurocode kan användas med ett bra resultat. Resultaten som fås från de idealiserade beräkningsmodellerna, vilka används för att beräkna byggnadens egenfrekvens, stämmer bra överens med resultaten då hela byggnaden modellerades. Skillnader på 3-13% noterades i de första moderna som kontrollerades. Detta stämmer dock bara för egenfrekvenser i translation och inte för egenfrekvenser vid vridning. Att lägga till en outrigger ökar drastiskt de lägsta egenfrekvenserna, med upp till 50% för Göteborg City Gate. (Less)
Please use this url to cite or link to this publication:
author
Svensson, Stefan LU and Castlen Rist, Viktor LU
supervisor
organization
course
VSM820 20161
year
type
H3 - Professional qualifications (4 Years - )
subject
keywords
Komfortkrav, Göteborg city gate, Design, Egenfrekvens, Acceleration, Eurocode, Höga hus, Preliminär dimensionering, Arbetsmetodik, High-Rise, Building, Wind-induced acceleration, Preliminary Design, Gothenburg City Gate, Comfort Requirements, Methodology
publication/series
TVSM-5000
report number
TVSM-5210
ISSN
0281-6679
language
English
id
8884631
alternative location
http://www.byggmek.lth.se/english/publications/tvsm-5000-masters-dissertations/
date added to LUP
2016-06-25 18:05:39
date last changed
2016-06-25 18:26:11
@misc{8884631,
  abstract     = {The construction of high-rise buildings has previously been limited in Sweden. Changes in society in recent years, related to urbanisation, economics and architectural standards have however resulted in a greater interest for the construction of high-rise buildings. When designing high-rise buildings, challenges are faced which often can be disregarded when designing lower buildings.

In this dissertation, a methodology which can be used in the preliminary design process of high-rise buildings is developed. The methodology is based on idealised calculation models and idealised finite element models, especially focused on the dynamical properties, natural frequencies and accelerations of the building. The report will describe how these calculations can be used to make the preliminary design of high-rise building and still obtain reasonable results. The work is focused on buildings with a structural system consisting of a concrete core with the possibility of adding outriggers. The dissertation also highlights the different phenomena related to high-rise buildings that needs to be considered in the preliminary stage, or later, in the design process. This includes, among other things, comfort requirements and wind induced accelerations. The stiffness is of great importance when designing high-rise buildings. For this reason, different ways to change the stiffness of the building are also analysed. 

To evaluate how reliable the idealised calculations and models are, a case study on an ongoing project is performed. The calculations are performed on Gothenburg City Gate, a 120 meter tall building that is intended to be built in Gothenburg. The case study follows the methodology developed, in order to show an example of how the idealised models can be used in the preliminary design. The results of the idealised calculations are compared with the results of the finite element analysis to evaluate the accuracy of the calculations.

The analysis shows that an idealised beam model of the building with varying stiffness will give sufficient results for the preliminary design. Also the shape function provided by Eurocode can be used with good results. The idealised calculations of the natural frequencies gives results that correspond with the more advanced FE-models, the results differed 3-13% in the first modes. This is however only true for translation modes and torsional modes are not accurate. Adding an outrigger to the building drastically increased the first natural frequencies of the building, by up to 50% for Gothenburg City Gate.},
  author       = {Svensson, Stefan and Castlen Rist, Viktor},
  issn         = {0281-6679},
  keyword      = {Komfortkrav,Göteborg city gate,Design,Egenfrekvens,Acceleration,Eurocode,Höga hus,Preliminär dimensionering,Arbetsmetodik,High-Rise,Building,Wind-induced acceleration,Preliminary Design,Gothenburg City Gate,Comfort Requirements,Methodology},
  language     = {eng},
  note         = {Student Paper},
  series       = {TVSM-5000},
  title        = {Methodology for preliminary design of high-rise buildings},
  year         = {2016},
}