Modeling Rectangular Reinforced Columns and Beams

Question:

Hi,

I was wondering how to model a rectangular reinforced concrete section in Midas Civil 2018. I tried to create a section using section properties but was unable to do so. The purpose of the rectangular reinforced concrete section is to mimic the properties of the abutment I am trying to model with a bridge. I was hoping to use the design features for this project as well.

Please advise.

Thanks!

Answer:

Hello,

Usually, it is recommended to model the abutment as plates rather than beam elements.  If that approach is acceptable, then just model the abutment as plate element of required thickness and then the reinforcement could be assigned for design.  A tutorial for plate design is attached herewith.
If its necessary to model the abutment as a rectangular section, simply define the rectangular section from Section Property.  The reinforcement could be assigned to this section from under the Design tab a shown in the image below.

Once the reinforcement is added, if these need to be considered for sectional stiffness, then that too could be done from the main control data as shown in the image below.

Hope this helps.  Kindly let us know if further assistance would be required.

Regards,
Nandeep
Technical Manager, MIDAS


Thanks for your response.


I am trying to enter in the appropriate rebar specifications into the rebar data section as shown.



The specifications I am trying to enter only have rebar along 2 of the 4 faces of the rectangular section. When I click redraw in this dialogue, I receive this error message. Please advise.



Thanks



Hello,

Glad the earlier response helped.  Kindly refer the image below on how the reinforcement could be entered for only any one of the sides of the faces.

Hope this helps.  Kindly let us know if further assistance would be required.

Regards,
Nandeep
Technical Manager, MIDAS


Hi Nandeep,


When I try to run the design features in Midas Civil 2018 (Design > Composite Design > Perform Design), I keep receiving the following message:


"No element can be designed. Make sure that Element, Section and Material types are Beam, Composite steel-I, and SRC respectively. In addition, check whether Rebar Data is defined."


How can I fix this problem?


Please advise.


Thanks!



Hello,

The issue is with the material property.  Currently, its simply assigned the steel material.  Kindly define a SRC material and assign it to the girder elements.


Also, as indicated in the error message, the reinforcements need to be assigned for the slab part.

Hope this helps.  Kindly let us know if further assistance would be required.

Regards,
Nandeep
Technical Manager, MIDAS


Hi Nandeep,


If my girder is not made of SRC (steel reinforced concrete) should I still change it in the material properties?


My slab is supposed to be a precast concrete deck and my girders are supposed to be steel grade 350AT.


Please advise.


Thanks



Hello,

In that case, I wouldn't recommend running the composite design at all since the design, well, isn't composite.  Also, model the beam section as steel beams only and not composite if the design needs to be done in midas Civil.

Regards,
Nandeep
Technical Manager, MIDAS

Hi Nandeep,


I am trying to perform design on the model similar to the tutorial posted here.



The only major difference is that the bridge in the tutorial is curved, while the one I have is straight. Could you please let me know what went wrong and why I can't seem to run the design while the tutorial can. Are there any video tutorials that can help me with using the design features.


In other words, what I am asking is: "Is it possible to run the design features on a Steel Composite I Girder bridge when the bridge has been modeled using the Steel Composite Bridge Wizard?" If so, how?


Attached is the most recent copy of the file I am working on and the tutorial I referred to earlier.

Thanks


Hello,

Since the slab is pre-cast and resting on the girder, the beam is not actually composite.  Hence I wasn't recommending the composite design.
To run the steel composite design, as I indicated earlier, the beam material has to be SRC type.
Videos for steel composite modelling could be referred on our site northamerica.midasuser.com.
Kindly let us know if further assistance would be required.

Regards,
Nandeep
Technical Manager, MIDAS


Hi Nandeep,


Once the precast deck is placed upon the steel girders, the deck and the girders will be connected using shear connectors and will act as a composite section. Does this change my ability to run the design functions in Midas?


Please advise.



Does SRC stand for Steel Reinforced Concrete? and if so does it refer only to when a material consists of a solid steel member encased in concrete, or is a section with a steel member connected to a concrete member considered a SRC material in Midas terms.

Hello Ryan,

Now, that clears up a lot on how to proceed!
In that case,using the steel composite section would be correct and the material would have to be SRC.  It does stand for Steel-Reinforced Concrete and has to be used for steel encased sections as well as for composite section.  With that definition, the steel composite design could be used to consider the composite action.
Kindly let us know if further assistance is required.

Regards,
Nandeep
Technical Manager, MIDAS


Hi Nandeep,


Okay that makes sense. Just to double check, I should only be changing the material properties of the girders to SRC. After changing this property the model should be able to run the design without problems. Is that correct?


Please advise.



Hello,

That is correct.  Kindly let us know if further assistance would be required.

Regards,
Nandeep
Technical Manager, MIDAS

Hi Nandeep,


I have made those changes to the model but still seem to be getting the same error message. I have changed the material to SRC and have added longitudinal reinforcement as well.


Please have a look at the model and advise.


Thanks



Hello,

Kindly provide the positions for design and output.
All the girder positions can be provided for design and this design could be checked in table.  However, for output position, kindly provide only critical locations, since this output position is to generate the excel file.  If all the locations are kept for output, then the excel report generation would take much time.
Kindly let us know if further assistance would be required.

Regards,
Nandeep
Technical Manager, MIDAS
Creation date: 10/4/2018 12:50 AM (dklee@midasit.com)      Updated: 10/4/2018 10:32 AM (dklee@midasit.com)
Files   
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Curved Steel Composite I-Girder Bridge Design to CSA.pdf
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