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Steel-to-concrete connections in narrow concrete corners

Carlson Bjernald, Daniel LU and Lönn, Emil (2022) In 0349-4969 VBKM01 20221
Division of Structural Engineering
Abstract
A commonly occurring problem when designing steel-to-concrete connections in corners with space deficits is the necessity for irregularly placed bolts with regards to design codes. The complexity of the calculations for the irregular placements of bolts generates the need to use simplified models during the design. This simplification could lead to differences between the design and the physical product, resulting in uncertainties regarding the connection's strength. The purpose of this thesis is to enhance the understanding of the effects on strength and the modes of failure for the connection due to the simplified models used and investigate whether the geometrical changes could be accounted for in design.

The study was performed... (More)
A commonly occurring problem when designing steel-to-concrete connections in corners with space deficits is the necessity for irregularly placed bolts with regards to design codes. The complexity of the calculations for the irregular placements of bolts generates the need to use simplified models during the design. This simplification could lead to differences between the design and the physical product, resulting in uncertainties regarding the connection's strength. The purpose of this thesis is to enhance the understanding of the effects on strength and the modes of failure for the connection due to the simplified models used and investigate whether the geometrical changes could be accounted for in design.

The study was performed using numerical analysis to simulate the real life behaviour of two models subjected to relevant load effects. The models were constructed in the finite element software Abaqus and validated as well as calibrated against laboratory tests performed at Luleå Technical University in 2013. The extent of the study was limited to a single case of simplified design with no regards to concrete reinforcement and tested in isolation from the entirety of the structure by the use of boundary conditions.

Results show the existence of a reduction in capacity for the irregular shaped connection compared to the design model and changes to the associated failure mode. However, further studies and parametrization is needed to find conclusive evidence that the found relations are relevant for the general case and could be used for future design. (Less)
Popular Abstract (Swedish)
Ett vanligt förekommenade problem vid utformning av stål-och betonganslutningar i hörn är att platsbrist kan ge upphov till anslutningar som är asymmetriskt utformade. De avvikande placeringarna på bultarna medför komplexa beräkningar och skapar ett behov av förenklade modeller vid design. Förenklingen kan leda till skillnader i brottsbeteende mellan designen och den fysiska produkten vilket kan leda till osäkerheter kring anslutningens hållfasthet. Syftet med den här avhandlingen är att öka förståelsen för förenklade beräkningsmodellers inverkan på anslutningens hållfasthet och brottmod samt undersöka huruvida geometriska skillnader kan beaktas i design.

Studien genomfördes som en numerisk analys av två modellers verkliga beteende... (More)
Ett vanligt förekommenade problem vid utformning av stål-och betonganslutningar i hörn är att platsbrist kan ge upphov till anslutningar som är asymmetriskt utformade. De avvikande placeringarna på bultarna medför komplexa beräkningar och skapar ett behov av förenklade modeller vid design. Förenklingen kan leda till skillnader i brottsbeteende mellan designen och den fysiska produkten vilket kan leda till osäkerheter kring anslutningens hållfasthet. Syftet med den här avhandlingen är att öka förståelsen för förenklade beräkningsmodellers inverkan på anslutningens hållfasthet och brottmod samt undersöka huruvida geometriska skillnader kan beaktas i design.

Studien genomfördes som en numerisk analys av två modellers verkliga beteende under påfrestan av relevanta lasteffekter. Modellerna konstruerades i finita element-programmet Abaqus och valideras samt kaliberades mot laboratoriska försök utförda vid Luleå tekniska universitet under 2013. Studiens omfattning avgränsades till ett enskilt fall av en förenklad modell utan beaktning av möjlig armering och testades i avskildhet utan interaktion med övriga konstruktionen med hjälp av randvillkor.

Resultaten påvisade förekomsten av kapacitetsbrist i anslutningen med avvikande bultplacering i förhållande till den förenklade modellen samt möjliga förändringar av dess brottsmod. Vidare studier och parametrisering krävs emellertid för att finna uteslutande bevis för att upptäckterna kan styrkas för det generella fallet och kan användas i framtida utformning. (Less)
Please use this url to cite or link to this publication:
author
Carlson Bjernald, Daniel LU and Lönn, Emil
supervisor
organization
alternative title
Stål-betonganslutningar i trånga hörn
course
VBKM01 20221
year
type
H3 - Professional qualifications (4 Years - )
subject
keywords
Concrete, steel bolts, concrete failure modes, Abaqus, numerical calculations, concrete cone failure, concrete damaged plasticity
publication/series
0349-4969
report number
22/5293
other publication id
LUTVDG/TVBK-22/5293
language
English
additional info
Additional supervisors at AFRY:
Fernando de Abreu Almeida
Rasoul Nilforoush

HAndledare: Ivar Björnsson
Examinator: Jonas Niklewski
id
9098186
date added to LUP
2022-08-25 12:46:45
date last changed
2022-08-25 12:46:45
@misc{9098186,
  abstract     = {{A commonly occurring problem when designing steel-to-concrete connections in corners with space deficits is the necessity for irregularly placed bolts with regards to design codes. The complexity of the calculations for the irregular placements of bolts generates the need to use simplified models during the design. This simplification could lead to differences between the design and the physical product, resulting in uncertainties regarding the connection's strength. The purpose of this thesis is to enhance the understanding of the effects on strength and the modes of failure for the connection due to the simplified models used and investigate whether the geometrical changes could be accounted for in design.

The study was performed using numerical analysis to simulate the real life behaviour of two models subjected to relevant load effects. The models were constructed in the finite element software Abaqus and validated as well as calibrated against laboratory tests performed at Luleå Technical University in 2013. The extent of the study was limited to a single case of simplified design with no regards to concrete reinforcement and tested in isolation from the entirety of the structure by the use of boundary conditions. 

Results show the existence of a reduction in capacity for the irregular shaped connection compared to the design model and changes to the associated failure mode. However, further studies and parametrization is needed to find conclusive evidence that the found relations are relevant for the general case and could be used for future design.}},
  author       = {{Carlson Bjernald, Daniel and Lönn, Emil}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{0349-4969}},
  title        = {{Steel-to-concrete connections in narrow concrete corners}},
  year         = {{2022}},
}