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Mekaniska kopplingar med hög deformationskapacitet för stommar byggda av prefabricerade betongelement

Eriksson, Tobias LU and Fritz, John LU (2016) In TVBK - 5250 VBK920 20161
Division of Structural Engingeering
Abstract
Precast concrete structures has no natural coherence of the frame as when the structure is cast in situ, which puts great demands on the ties between the prefabricated concrete elements regarding the resistance and deformation capacity. The ties that are used today often consist of straight ribbed bars embedded in concrete and therefore have limited deformation capacity. This means that the opportunities to create alternative load paths, if a local failure in the structure occurs, thru catenary action are limited.
The division of Structural Engineering at the Faculty of Engineering, LTH, has come up with three suggestions of ties with potential for high deformation capacity such that catenary action can provide alternative load paths.... (More)
Precast concrete structures has no natural coherence of the frame as when the structure is cast in situ, which puts great demands on the ties between the prefabricated concrete elements regarding the resistance and deformation capacity. The ties that are used today often consist of straight ribbed bars embedded in concrete and therefore have limited deformation capacity. This means that the opportunities to create alternative load paths, if a local failure in the structure occurs, thru catenary action are limited.
The division of Structural Engineering at the Faculty of Engineering, LTH, has come up with three suggestions of ties with potential for high deformation capacity such that catenary action can provide alternative load paths. The focus of the report is to evaluate and compare the traditional ties with the three new ties both theoretically and experimentally. This report will also investigate and demonstrate the advantages of using an alternative load bearing system in design against accidental action.
The result indicate that one of the new ties may be implemented after large-scale tests have been made. Although uncertainty remains regarding the dynamic capacity, the thesis clearly demonstrates that the implementation of the new tie with a high deformation capacity results in improved static capabilities, thereby allowing the use of catenary action as design against accidental action. The proposed tie solution also gives the designer the ability to control the deformation of the floor structure and the designer can thus obtain a higher safety against accidental actions and progressive collapse. The design of the deformation for the new tie can thus be adapted to the circumstances. However, it is important to point out that the geometry of the pre-deformation must comply with the rules in Eurocode regarding the bending radius so that the steel is not damaged. (Less)
Abstract (Swedish)
Förtillverkade betongkonstruktioner har inte någon naturlig sammanhållning av stommen, som i en platsgjuten konstruktion, vilket medför stora krav på de mekaniska kopplingarna mellan de prefabricerade betongelementen avseende bärförmåga och deformationskapacitet. Dagens mekaniska kopplingar utgörs ofta av ingjutna raka kamstänger och har därför en begränsad deformationskapacitet vilket medför att möjligheterna att skapa alternativa lastvägar vid ett lokalt brott i stommen genom exempelvis linverkan begränsas.
Avdelningen för Konstruktionsteknik på Lunds Tekniska Högskola har tagit fram tre stycken förslag på mekaniska kopplingar med potential till hög deformationskapacitet, sådana att linverkan kan skapa alternativa lastvägar. Rapportens... (More)
Förtillverkade betongkonstruktioner har inte någon naturlig sammanhållning av stommen, som i en platsgjuten konstruktion, vilket medför stora krav på de mekaniska kopplingarna mellan de prefabricerade betongelementen avseende bärförmåga och deformationskapacitet. Dagens mekaniska kopplingar utgörs ofta av ingjutna raka kamstänger och har därför en begränsad deformationskapacitet vilket medför att möjligheterna att skapa alternativa lastvägar vid ett lokalt brott i stommen genom exempelvis linverkan begränsas.
Avdelningen för Konstruktionsteknik på Lunds Tekniska Högskola har tagit fram tre stycken förslag på mekaniska kopplingar med potential till hög deformationskapacitet, sådana att linverkan kan skapa alternativa lastvägar. Rapportens fokus ligger på att utvärdera och jämföra raka kamstänger med de tre nya mekaniska kopplingar både teoretiskt och experimentellt. Rapporten ska även utreda och påvisa fördelarna med att utnyttja ett alternativt lastbärande system vid dimensionering mot olyckslast.
Resultaten visar att ett av kopplingsförslagen kan tänkas implementeras efter att mer storskaliga tester har gjorts. Även fast oklarheter kvarstår angående den dynamiska kapaciteten har detta examensarbete tydligt påvisat att en implementering av kopplingar med en hög deformationskapacitet medför en förbättrad statisk kapacitet och möjliggör därmed utnyttjandet av linverkan för att hantera olyckslaster. Den föreslagna kopplingslösningen ger även projektören möjlighet att styra bjälklagets deformationsförmåga och projektören kan på det sättet SRapporten åstadkomma en högre säkerhet mot olyckslaster och fortskridande ras. Kopplingarnas deformationsdesign kan alltså anpassas efter förutsättningarna. Det är dock viktigt att poängtera att fördeformationens utseende följer Eurokods regler angående bockningsradie så att stålet inte skadas. (Less)
Please use this url to cite or link to this publication:
author
Eriksson, Tobias LU and Fritz, John LU
supervisor
organization
alternative title
Ties with high deformation capacity in precast structures
course
VBK920 20161
year
type
H3 - Professional qualifications (4 Years - )
subject
publication/series
TVBK - 5250
report number
TVBK - 5250
ISSN
0349-4969
language
Swedish
additional info
Examinator: Oskar Larsson
id
8885167
date added to LUP
2016-06-27 16:00:51
date last changed
2016-06-27 16:00:51
@misc{8885167,
  abstract     = {Precast concrete structures has no natural coherence of the frame as when the structure is cast in situ, which puts great demands on the ties between the prefabricated concrete elements regarding the resistance and deformation capacity. The ties that are used today often consist of straight ribbed bars embedded in concrete and therefore have limited deformation capacity. This means that the opportunities to create alternative load paths, if a local failure in the structure occurs, thru catenary action are limited. 
The division of Structural Engineering at the Faculty of Engineering, LTH, has come up with three suggestions of ties with potential for high deformation capacity such that catenary action can provide alternative load paths. The focus of the report is to evaluate and compare the traditional ties with the three new ties both theoretically and experimentally. This report will also investigate and demonstrate the advantages of using an alternative load bearing system in design against accidental action.
The result indicate that one of the new ties may be implemented after large-scale tests have been made. Although uncertainty remains regarding the dynamic capacity, the thesis clearly demonstrates that the implementation of the new tie with a high deformation capacity results in improved static capabilities, thereby allowing the use of catenary action as design against accidental action. The proposed tie solution also gives the designer the ability to control the deformation of the floor structure and the designer can thus obtain a higher safety against accidental actions and progressive collapse. The design of the deformation for the new tie can thus be adapted to the circumstances. However, it is important to point out that the geometry of the pre-deformation must comply with the rules in Eurocode regarding the bending radius so that the steel is not damaged.},
  author       = {Eriksson, Tobias and Fritz, John},
  issn         = {0349-4969},
  language     = {swe},
  note         = {Student Paper},
  series       = {TVBK - 5250},
  title        = {Mekaniska kopplingar med hög deformationskapacitet för stommar byggda av prefabricerade betongelement},
  year         = {2016},
}