UmarMakhzumi

Hello Everyone, The company "Encon Pakistan" is about Energy Efficient Buildings and design. I have looked up their Facebook page and some photos that they have shared. I am posting some photos below. The link to FB page is: https://www.facebook.com/ENCON.Pakistan/ My observation of the photo below is that there is no real building envelope design involved and the whole Encon thing is just a marketing gimmick. Masonry laid like shown below has cold bridging everywhere, the air pockets might increase value of R but what does a significant increase to an insignificant quantity mean? The R value obtained doesn't compare up to standard insulation used between walls. Also, posts like "20% reduction" in cooling energy are meaning less without knowing the basis and assumptions behind the graph. I would like to get your comments on this. What do you think and whats your engineering take? Thanks.

Also the teflon and grout in Section C-C need to extend thill the end of ledge. Thanks.

You are welcome. You can calculate the maximum inelastic displacement at that level/ story and make sure your gap considers that. In that way, the building movements would be covered too. Thanks.

I don't see an issue with that. From section sizes, I guess you are designing a Pedway between two office buildings. If you are worried about compliance issues (that your design meets regulatory), you need to check with the authority on applicable codes but from an engineering point of view, what you have above should be okay as long as your numbers are correct. Looks reasonable as 300mm can expand or contract. Would be unreasonable if there is only somewhat constant weather all year round. Anyway, I haven't done any of these myself and my answer is based on "feel" of the what I am looking at. You should also consider construction tolerance when doing expansion joint calculations. Width for 36mm dia bolt should be 38mm based on CISC Handbook. If you are following American codes, check width based on AISC Handbook. Is it a bridge or Pedway. What you read in ASCE should have given you some idea about what to base your calc on. Thanks.

Rummaan17, Please also share Section C-C. Thanks.

You question has been answered. I will just add that make sure there are no future additions to the building in terms of stories. Talk to Architect and Client and if there are, make a model with future/ potential stories and recheck your numbers. Thanks.

Table 16N UBC 97 provides some insight. Thanks.

Hi Chasm9a, You can have a look at discussion below that allow you to show "Story Max/average displacement -----> ratio value" from ETABS to verify if minimum torsional eccentricity needs to be increased or not. In other words, it would also tell you if you need additional shear-walls. As far as your current framing goes - without knowing any building information- I would provide a shear wall (If North is up, then the shear wall would be in East West Direction) in all the three corners where there is nothing right now. Thanks.

I don't have any bridge experience but I would like to look at the drawings before commenting. Please provide drawings. Thanks.

Read More: http://www.cbc.ca/news/canada/sudbury/robert-wood-trial-begins-1.3748401 If this were Pakistan, the chances of criminal indictment would be zero. Whats your take? Thanks.

What's your take guys? https://en.wikipedia.org/wiki/Trolley_problem

Sweet. This is much simple now. You can have 50 MPa concrete tested for abrasion and submit a mix design for a normal weight 30 MPa concrete having equal abrasion to that of 50 MPa with the help of additives. Lafarge will be able to help you with that. See that attachment for concrete abrasion testing. Cheers! Standard Test Methods Abrasion Resistance.pdf

@rummaan17, I hear you and that's why we have this forum. All these questions are legit. @Rana might be able to shed better light because of his experience in commercial design. If not, we can all agree on most rational conclusion and run numbers to do sanity checks. Cheers

Yes, you can do like that. The difference in results would not be significant if both conditions are done appropriatley. Thanks.

I think there are some items that need to be addressed with the above approach. The ULS state being checked should be done for only one stiffness modifier. The basis aren't consistent when we are using different modifiers for temperature load and others for active loads as both relate to finding the most critical ULS condition under combined loads. Use of separate model can be justified for either where code requires a special design condition to be checked like Dual Systems or when a different limit state is being checked like serviceability. Second comment that I have is that temperature gradient across a member would not only cause axial loads but as well as curvature/ bending. If ETABS doesn't allow application of temperature gradient then these loads need to be applied to reflect the actual loading condition. You can challenge your peer review team as long as you can defend your position clearly. Do you have load development document created for this project that summarizes basis of all loads? Thanks.

Rummaan17, Thanks for the summary. It does provide some useful background on the topic. Temperature loads should be applied but only to areas exposed to temperature differential (Roof slab or periphery members if exposed). Lets get some feedback from @Rana as he might has more experience on temperature load application in commercial design and see where this goes. Thanks.

Yes, that would be correct for columns stiffer than beam. Thanks.

Thanks AQ for sharing the full resolution drawings. Very interesting. Well, the first thing that comes to my mind is why the compressive strength of concrete is so important for your design team. Let me elaborate on this. What is your project team getting by using a 50 MPa concrete that it is not getting by using a 35 MPa concrete other than compressive strength? Concrete has a number of properties so I would like to understand that if compressive strength solely is driving this? If yes, then there might be another design that would allow use of lower strength concrete. The solution would lie in a design that mitigates water impact or whatever the design basis is to allow use of lower strength concrete mix. So in summary. I am asking you not to focus on negative impacts of high strength concrete but to change your design to lower the requirement which is triggering high strenght demand. If compressive strength is not main reason rather its some properties assigned with higher strength concrete, then different mix designs with lower compressive strength might be able to provide same level of non-strength related properties as that of 50 MPa concrete while also keeping lower C3A content. Thanks.

@Rana, Good comments. I have got a few questions about the subject that I believe will make this topic more detailed. I am assuming that the discussion here is for temperature design for the final finished building and we are not discussing temperature affects cobsidering sequential construction (which could be an interesting case- general comment). Here are the questions: Temperature loads generally produce tension or compression. For the current case, I assume there would be some slabs connected to shear wall. Considering that the building is insulated at all level and temperature is maintained inside the building once it would be operational, temperature differential would exists at top slab (roof) , which would likely induce moment in the wall. Why isn't that being considered. Also, the discussion above talks about temperature induced load in shear wall as axial load. I would like to know the source of axial tension in shear wall if temperature in building is maintained? I am not sure what would be the best way to consider temperature loads concurrent with other loads, but what I have done is run a separate load combination as temperature load and add that load combination to other load combos (RISA 3D). I design steel structures for Oil and Gas industry so genre is different. In my opinion, the affect of temperature on shear wall should be considered in combination with other working loads. The design would be similar to that of a beam column subjected to axial load. I am not sure if additional reduction is stiffness is justified based on isolated consideration of temperature load. What do you think ? Thanks.

@Abid Qasmi, I would love to help you with it but the only problem is that I don't have ETABS installed, my computer is non-windows (so won't be able to do an off license installation). However, I would suggest that you try to experiment with the options and post your feedback here, and it may help resolve your issue. How about you define RSA load as earthquake. I believe that is the option in ETABS. Thanks.

Hi Alinalysis, Instead of labelling conditions as pinned or fixed please consider them interms of load path. Your observations reflect that for case of extremely stiff beams (Moment of Inertia of beam >> Moment Inertia of Column), relatively speaking, there would be no rotational restraint at end of beam and therefore no moment, which should be the case. Hope this answers your question. How about having super big cross-sectional columns and small cross-sectionall beam, would it affect your result? Can you guess the result without running the numbers. Thanks.

Hi @Yaseen H, Thanks for your feedback. We do have a mobile skin for the forum. The forum as a default displays that skin when you login through your cell/ smart phone. Regarding Tapatalk, it might be a good option for the forum but right now our financial resources are more focused on growth and advertising. That is definitely something we will look into in near future. Cheers!

Hi Abid, I am not clear about your first question. For your second question, please see the attachment. Ritz analysis vs Eigen Analysis.pdf Cheers!

AQ, Can you post a pdf of the attachments. Snapshots are hard to read. When you say high strength concrete.. what is the strength of that concrete and what is the strength of normal concrete? My first reaction is that why not just pour all the concrete as high strength, then you don't have to do 2 layers or 2 separate pours. Anyway, answer the questions and we will see form there. Thanks.