Creation of models of decks in Midas Civil

Question

Creation of models of decks in Midas Civil

James Sorenson (Civil/Environmental)

(OP)

20 Apr 23 15:20

Hello everyone!
On the forums, I came across that Midas Civil has a weak Wizard for creating design models for bridge spans. We have solved this problem and can help in creating model elements for beam bridges of complex shape.
We only need the axis of the main beams in the plan, the edges of the plate and the cross section of the bridge in dwg. Creating the model will take from an hour to 1 day (depends only on how quickly I read the message).
Bridges can be of any length and width, curved shape in plan, with variable width. Steel composite bridge or steel bridge with stiffened deck are possible. According to the type of main beams-wide boxes of plate elements for narrow exits, or line elements in the form of I-beams or boxes connected to the plate by rigid inserts.
I have attached screenshots of models and an example of one of them. Write, I will be glad to help, jamesbridgemidas@gmail.com

https://res.cloudinary.com/engineering-com/image/upload/v1682003715/tips/capabilities_skocjy.pdf

https://res.cloudinary.com/engineering-com/raw/upload/v1682003725/tips/example_hhhkpr.mcb

VoyageofDiscovery (Structural) · Answer 1 · 2023-04-21 12:29:37

Great effort! With skewed bridges, I do not skew the deck plates as my deck main rebars run perpendicular to the edge of the deck. With continuous bridges, the deck plate in negative moment regions could be cracked sections depending on the designer. Further, watch the ratios of individual plate size dimensions.

VoD

Lomarandil (Structural) · Answer 2 · 2023-04-22 18:01:56

Very cool -- and useful. I've definitely struggled to create what should be simple bridge models in MIDAS.

What approach are you taking?

James Sorenson (Civil/Environmental) · Answer 3 · 2023-04-23 21:00:51

Dear colleagues, thank you for your interest!
All models are created automatically according to the algorithm (code), including the elements themselves, constant loads and the stages of concreting the slab. Data is imported into Midas via an MCT file.
We set cracked concrete zones by default in a quarter of the span length from the intermediate supports (see the attached example). This usually corresponds to the zero moment zone. During the calculation process, the engineer can specify both the length of the cracked zone and the reduced modulus of elasticity, taking into account the selected section of the longitudinal reinforcement.
As for the skew bridges, I gave an example in the picture of how the algorithm creates a grid. It does not use triangular elements. Therefore, if we have cross beams combined with a plate and skew supports with an angle of more than 10°, then we have to create a model using standard Midas tools.
If there are no cross beams, then the cosine up to 30 ° does not reduce the accuracy of the result (of course, subject to the general recommendations on the aspect ratio of plate elements). Because firstly, in Midas, you can look at the forces on the local and global axes, and secondly, the transverse reinforcement is mainly loaded with a local transverse moment (between the main beams), and we do not use a general bridge model to calculate it.
I can add that according to this algorithm, models of more than 100 bridges have been created, on which traffic is already open.
Of course, we cannot transmit the algorithm, but we can help in creating the models themselves if you send the initial data I wrote about above.
Best regards, James

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Creation of models of decks in Midas Civil