• Registered: 2011-08-23
  • Posts: 8

Topic: Influence of construction sequence

Hello,

My project is about the ZIP girder system: illustration: http://www.spanbeton.nl/images/file/zip … 6vPL25E5Y0

I like to model that inverted T beam non-linear in ATENA 3D including the deck. For the stresses in the beam the following sequence is of importance:
- 1. The beam is prestressed and only loaded by own weight. (only stiffness of concrete beam)
- 2. The formwork is installed and the concrete of the deck is poured. The cross-section of the girder is bearing the wet concrete of the deck and the loads from 1.
- 3. The traffic load is applied. The concrete deck is hardened. The load is beared by the whole cross-section. (stifness of beam and deck together).

Why this question:
- when I model the whole system the prestressing incorrectly flows into the deck.
- The own weight of the girder is also beared by the deck.

I am modelling non-linear, so I can't superpose the results to each other...

Thanks a lot for the answer.

Kind regards,
Evert

Quote Post 1

  • dpryl
  • CC software developer
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  • Registered: 2007-07-13
  • Posts: 1,107

Re: Influence of construction sequence

Hello Evert, this can be modelled using the Construction Process - see sections 3.8.2.1 Construction cases, 3.8.2.2.4 Properties, and 3.8.5.2 Analysis steps of the ATENA 3D User's Manual.

Another option is to use the NLCem2Variable material for the deck (first very low elastic modulus, than normal). This is the best way if reinforcements protruding from the beam into the deck are to be modelled from the beginning (using the construction cases approach would let the reinforcement "hang in the air" before the deck is added, which is a problem as the bars only have axial stiffness).

dpryl's Website

Quote Post 2

  • Registered: 2011-08-23
  • Posts: 8

Re: Influence of construction sequence

Great that this is possible!

Indeed there is reinforcement protuding from the beam in the deck. Perhaps is it a solution to stop this reinforcement at the top of the beam? At the same place in the deck the rest of the reinforcement can be modelled? Than no reinforcement nodes are outside concrete. Or is that not a good idea?

Evert

Quote Post 3

  • dpryl
  • CC software developer
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  • Registered: 2007-07-13
  • Posts: 1,107

Re: Influence of construction sequence

Yes, that should work in your case (once a user had to include some girder from the very beginning such that the compressive stiffness could help to carry the dead weight of the beam, and then the NLCem2Variable was the only way).

dpryl's Website

Quote Post 4