Jämförande beräkningar av betongpelare
(2018) VBK920 20171Division of Structural Engineering
- Abstract (Swedish)
- När en betongpelare dimensioneras ska dess kritiska tvärsnitt bestämmas och dimensioneras med hänsyn tagen till pelarens slankhet och andra ordningens effekter. Dessa parametrar kan begränsa pelarens bärförmåga och riskera knäckning istället för att tvärsnittets kapacitet blir avgörande. För att uppskatta pelarens slankhet beskrivs i Eurokod t.ex. den nominella styvhetsmetoden och den generella metoden som båda kräver iterativa beräkningar, vilket gör att program som Concrete Column och Frame Analysis blir mycket användbara. Dock indikerar erfarenheter från konstruktörer på skillnader i armeringsmängder mellan dessa program. För att utreda eventuella skillnader och dess orsaker har denna studie genomförts. Resultatet visar på stora... (More)
- När en betongpelare dimensioneras ska dess kritiska tvärsnitt bestämmas och dimensioneras med hänsyn tagen till pelarens slankhet och andra ordningens effekter. Dessa parametrar kan begränsa pelarens bärförmåga och riskera knäckning istället för att tvärsnittets kapacitet blir avgörande. För att uppskatta pelarens slankhet beskrivs i Eurokod t.ex. den nominella styvhetsmetoden och den generella metoden som båda kräver iterativa beräkningar, vilket gör att program som Concrete Column och Frame Analysis blir mycket användbara. Dock indikerar erfarenheter från konstruktörer på skillnader i armeringsmängder mellan dessa program. För att utreda eventuella skillnader och dess orsaker har denna studie genomförts. Resultatet visar på stora skillnader i andra ordningens moment och armeringsmängder mellan beräkningsprogrammen, där Frame Analysis ofta ger de lägre värdena, men också att programmen placerar armeringsmängd på olika sätt i tvärsnittet. Den huvudsakliga orsaken till skillnader beror på att Concrete Column använder den nominella styvhetsmetoden och Frame Analysis den generella metoden för att ta fram dimensionerande moment och då dessa blir olika stora påverkas erforderlig armeringsmängd. En annan orsak till skillnaderna är att programmen beaktar momentfördelning och upplagsdefinitioner på olika sätt. Denna studie syftar till att öka förståelsen för dimensionering av betongpelare och beräkningsprogrammen samt öka tryggheten hos konstruktörer, vilket kan uppfyllas genom att skillnader mellan programmen har kunnat förtydligas. (Less)
- Abstract
- When designing a concrete column, the critical cross section must be determined with regard to the column slenderness and second order effects. These parameters could limit the columns resistance by the risk of buckling instead of the cross sections resistance deciding the limit state. Eurocode describes among three methods the nominal stiffness method and the general method to approximate the slenderness and second order effects. Both these methods demands iterative calculation processes and therefore the programs Concrete Columns and Frame Analysis are useful. Experiences from structural engineers indicates differences in reinforcement amounts given by these programs. This study aim to evaluate possible differences and the reason for... (More)
- When designing a concrete column, the critical cross section must be determined with regard to the column slenderness and second order effects. These parameters could limit the columns resistance by the risk of buckling instead of the cross sections resistance deciding the limit state. Eurocode describes among three methods the nominal stiffness method and the general method to approximate the slenderness and second order effects. Both these methods demands iterative calculation processes and therefore the programs Concrete Columns and Frame Analysis are useful. Experiences from structural engineers indicates differences in reinforcement amounts given by these programs. This study aim to evaluate possible differences and the reason for these between the two programs and analytical hand calculation methods. The result shows large differences in size of second order moments and amount of reinforcement between the programs, Frame Analysis often gives the lower values. Also differences in placement of the reinforcement in the cross section could be shown. The main reason is derived to the different methods used in Concrete Column (the nominal stiffness method) and Frame Analysis (the general method) used to approximate the second order moment which will affect the amount of reinforcement. The differences also depend on how the programs considers the moment distribution and joint types. Another aim of the study is to contribute to the understanding of calculation methods and the programs above and make structural engineers more comfortable in the design process, which can be fulfilled by clarifying the differences in the methods. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/8963326
- author
- Rosenqvist, Caroline LU
- supervisor
- organization
- alternative title
- Comparative calculations of concrete columns
- course
- VBK920 20171
- year
- 2018
- type
- H3 - Professional qualifications (4 Years - )
- subject
- keywords
- Betongpelare, armeringsmängd, andra ordningens teori, slankhet, nominella styvhetsmetoden.
- report number
- TVBK-5268
- language
- Swedish
- id
- 8963326
- date added to LUP
- 2018-11-29 08:51:27
- date last changed
- 2018-11-29 08:51:27
@misc{8963326,
abstract = {{When designing a concrete column, the critical cross section must be determined with regard to the column slenderness and second order effects. These parameters could limit the columns resistance by the risk of buckling instead of the cross sections resistance deciding the limit state. Eurocode describes among three methods the nominal stiffness method and the general method to approximate the slenderness and second order effects. Both these methods demands iterative calculation processes and therefore the programs Concrete Columns and Frame Analysis are useful. Experiences from structural engineers indicates differences in reinforcement amounts given by these programs. This study aim to evaluate possible differences and the reason for these between the two programs and analytical hand calculation methods. The result shows large differences in size of second order moments and amount of reinforcement between the programs, Frame Analysis often gives the lower values. Also differences in placement of the reinforcement in the cross section could be shown. The main reason is derived to the different methods used in Concrete Column (the nominal stiffness method) and Frame Analysis (the general method) used to approximate the second order moment which will affect the amount of reinforcement. The differences also depend on how the programs considers the moment distribution and joint types. Another aim of the study is to contribute to the understanding of calculation methods and the programs above and make structural engineers more comfortable in the design process, which can be fulfilled by clarifying the differences in the methods.}},
author = {{Rosenqvist, Caroline}},
language = {{swe}},
note = {{Student Paper}},
title = {{Jämförande beräkningar av betongpelare}},
year = {{2018}},
}