Warning in RAM: Bolt slip class does not match slip resistance recommendations

Hi Vishal. I am looking for clarification of a few points from the development team and will respond to you after I recieve these.

One more point, I noticed that

Results for bearing & non-bearing splices are same!!!!!

Please ensure at your end.

It is for non bearing type of splices irrespective of selection (I haven't checked all the formulas, only could check few initial points as well as reference is given as SCI 358 p185, which is for Non-bearing splices).

Let me know whether you also notice the same.

Regards,

Vishal

Hi Vishal, I noticed that the refereance to page 185 was for non-bearing splices and queried this with the development team. The page number should be 176 for bearing splices. With reference to your query (3) i think this is simply due to the SCI publication giving design recommendations for the web and flange seperately. I will look into the results for bearing and non bearing  splices.

Hi Vishal

Please see response from development team. Your queries are shown in bold and the response in italics.

I am designing a column splice of bearing type according to EN 1993-1-8. There exists net tension in the flange hence I will have to use preloaded bolts and hence apply slip resistance checks.

1. Now when I enable check slip resistance, I don’t find any option to enter slip factor for it. Then how does RAM cjhevck the slip resistance of the joint?

EN connection design in order to check slip resistance needs that user choose the corresponding bolt diameter. For slip resistance checks the application have bolts with different slip factor values. For example:

If user choose normal bolt diameter with “Check slip resistance” flag turned on; the application will show the design warning “Bolt slip class does not match slip resistance recommendations”.

This methodology has recently change for Indian connections, now users when turn on the “check slip resistance” flag the user is capable to set also the slip factor; but currently only available for Indian connection design.

 2. Even after applying slip resistance the following warning appears in the result:

‘Bolt slip class does not match slip resistance recommendations’

 What is the meaning of this warning, as far as I know only 8.8 and 10.8 grades are allowed to be used for preloaded application and IO have selected the 8.8 grade bolt, so what is the meaning of this warning?

As explained in the last questions; the warning is displayed due the user choose normal bolt diameter using the “Check slip resistance” flag turned on. Just need to choose one of the bolts using slip factor and the warning will disappear.

 3. Why web and flange coverplates are checked in separate connections?

Because they are two separate connections, the web cover plate is one and the flange cover plate is the other. In other codes not only a plate could be user to join the webs but also double angles, etc. That is the reason of why we separate shear and moment connections so we can combine them if required.

4. What is the purpose of providing additional plate from inside of column, as far as I know SCI allows use of cover plate either from inside or outside.

I am using RAM Connection integrated with STAAD.Pro V8i 20.07.11.90. 

Green book describes the use for internal cover plates. The EN connection design follow the procedures described in:

The consideration or not of the internal cover plates affect directly to bending capacities in major and minor axis; also affecting in plate shear capacity.

If user turn on the flag the interior plate will be considered in the capacities.

Also, in the results:

In above it refers to SCI P358 p 185 however, that page refers to non-bearing splices and NOT bearing splices:

The references in the report results are correct. The user is reporting the flange cover plate from a Non-bearing connection design.

The only template that user can assign to have a bearing type connection is the “Smart WAC CS”; which use a division plate between columns. Also is noticed that the model is using standard bolts with the check slip resistance flag turned on. Once the user change to the correct one the warning will disappear.

Should the refereance be to SCI P358 p 176?

The only template exclusively for Bearing Type is WAC CS (Web angle cleats – Column splice) which uses the division plate between the columns. If user model use the correct template (bearing type) the reference should be the one described above.

Hi Vishal

Please see response from development team. Your queries are shown in bold and the response in italics.

I am designing a column splice of bearing type according to EN 1993-1-8. There exists net tension in the flange hence I will have to use preloaded bolts and hence apply slip resistance checks.

1. Now when I enable check slip resistance, I don’t find any option to enter slip factor for it. Then how does RAM cjhevck the slip resistance of the joint?

EN connection design in order to check slip resistance needs that user choose the corresponding bolt diameter. For slip resistance checks the application have bolts with different slip factor values. For example:

If user choose normal bolt diameter with “Check slip resistance” flag turned on; the application will show the design warning “Bolt slip class does not match slip resistance recommendations”.

This methodology has recently change for Indian connections, now users when turn on the “check slip resistance” flag the user is capable to set also the slip factor; but currently only available for Indian connection design.

 2. Even after applying slip resistance the following warning appears in the result:

‘Bolt slip class does not match slip resistance recommendations’

 What is the meaning of this warning, as far as I know only 8.8 and 10.8 grades are allowed to be used for preloaded application and IO have selected the 8.8 grade bolt, so what is the meaning of this warning?

As explained in the last questions; the warning is displayed due the user choose normal bolt diameter using the “Check slip resistance” flag turned on. Just need to choose one of the bolts using slip factor and the warning will disappear.

 3. Why web and flange coverplates are checked in separate connections?

Because they are two separate connections, the web cover plate is one and the flange cover plate is the other. In other codes not only a plate could be user to join the webs but also double angles, etc. That is the reason of why we separate shear and moment connections so we can combine them if required.

4. What is the purpose of providing additional plate from inside of column, as far as I know SCI allows use of cover plate either from inside or outside.

I am using RAM Connection integrated with STAAD.Pro V8i 20.07.11.90. 

Green book describes the use for internal cover plates. The EN connection design follow the procedures described in:

The consideration or not of the internal cover plates affect directly to bending capacities in major and minor axis; also affecting in plate shear capacity.

If user turn on the flag the interior plate will be considered in the capacities.

Also, in the results:

In above it refers to SCI P358 p 185 however, that page refers to non-bearing splices and NOT bearing splices:

The references in the report results are correct. The user is reporting the flange cover plate from a Non-bearing connection design.

The only template that user can assign to have a bearing type connection is the “Smart WAC CS”; which use a division plate between columns. Also is noticed that the model is using standard bolts with the check slip resistance flag turned on. Once the user change to the correct one the warning will disappear.

Should the refereance be to SCI P358 p 176?

The only template exclusively for Bearing Type is WAC CS (Web angle cleats – Column splice) which uses the division plate between the columns. If user model use the correct template (bearing type) the reference should be the one described above.

Hello rtully14,

Thanks for your feedback and please see my opinion below:

For points 1 & 2:

Even after selecting grades M20 HSFG (mu_0.2), warning does not disappear,

Also I dont find any slip resistance check in the connection report as well.

What about the grade of bolt, i think it is by default 8.8?

Since results for M20 8.8 & M20 HSFG (mu_0.2) match irrespective of mu factor.

For point 3:

I thought if both were combined, it would have been easy to visualize from execution point of view.

For point 4:

I think there are 3 options provided by SCI,

External cover plate, internal cover plate and combined external & internal. 

But RAM do not provide option of internal cover plate only? 

If both bearing type & non bearing type splices provide same result (corresponding to non bearing splices), what is the intention of making 2 separate templates?

I was comparing it with bearing type splices design criteria.

Where i can find the WAC CS template? (code?)

Please let me know the difference in basic connections & smart connections, 

since i find templates are same in both.

Thanks for your patience.

Best Regards,

Vishal

Hi Vishal. You can find the WAC CS template in the RAM Connection module as follows:

I will get back to you as soon as I have an answer to your other queries.

Hi Vishal, regarding the difference between basic and smart connections, please see:

https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/8105/ram-connection-capabilities-and-modeling-faq

This seems to be CONNECT Edition, since i don't find this template in RAM connection integrated with STAAD Pro V8i 20.07.11.90.

Looking forward to your feedback for remaining points.

Sorry, the template exists in the current version, only sequence is changed in the connect edition.

Don't forget to look after the points to be cleared.