UmarMakhzumi

What are your thoughts on this collapse?

Fatima, How about you provide another CF3 between F2A and F3 columns and center the water tank so that the additional load due to water is equally distributed to 4 columns. Just building on what Ayesha has said. Thanks.

Hi Umair, Can you please explain the problem? Thanks.

Hi rummann17, Please see this: Thanks.

Hi Syed, You need to know the crane size and use impact factors and load combinations in MBMA to get appropriate reactions. Thanks.

Backstay Effect. See attached and: Thanks. Backstay Effect.pdf

Hi Bilal, Your best bet is to get this reviewed by an architect (not a structural engineer) for compliance with Building Code rules applicable to layout of space. Thanks.

Please see this: http://docs.csiamerica.com/help-files/etabs/Menus/Define/Material_Properties/Additional_Material_Damping_Form.htm Thanks.

You can try refining your mesh and using live load reduction. Generally, over-stress in foundation is generally ignored if it is localized. Your area is kind of localized. You have to make a judgement call considering how much is the over-stress. Thanks.

Thanks for sharing. This is interesting. FYI: https://en.wikipedia.org/wiki/Infinite_monkey_theorem

It should be different. The bearing capacity of soil is a function of width of foundation. I know this sounds wierd but this is from textbooks. A geotech consultant would be able to tell you how different it would be. If you can't communicate with the geotech consultant, you can use the same capacity. Should be a conservative thing to do in my opinion. Thanks.

So lets locate the negative mass source values. The image that you have attached in the post above says that: Share that table and lets probe it. So far it looks like that you might have applied equipment loads to a slab and this error that you are getting is because of meshing. I am not sure if that is the case, this is my guess. Anyway, please share the table and we can pin point the problem area. Also, for general information, this is what ETABS does to convert load patterns into Mass Source. and also this: Thanks.

Hi Ahsan, What are the load combinations for which your raft stresses are exceeding allowable? Thanks.

Hi Aizaz, Please check the attachment. For cracking modulus you can use modulus of rupture of concrete based on code you are following. Thanks.

Hafsa, What is the exact error that you are getting. Please share the error code and description. Thanks.

Hello Everyone, You might have seen a lot of buzz on social media about Pakistan Engineering Council Elections 2018. It is great that candidates are coming forward with manifestos and idea to bring PEC up to speed. I am writing this post to highlight that please make sure that you vote in these elections and do spend some time doing little research on the person you want to vote. Chairman PEC is a very prestigious position and if we can get the right person in, a lot can be changed for current and prospect engineers. What do you say? Thanks.

@EngrUzair, @waqar saleem and @BAZ can help.

civilengnr, There are various topics with very useful attachments and all the links are working. You need to be logged in to your account to download the attachments: You can assign shell properties, see what stresses you get against applied loads and provide required reinforcement. This is the summary of dome design. Thanks.

Welcome aboard Ali.

All, I came across this today and thought would share. For more details and FAQs, please check out: https://www.aisc.org/why-steel/SpeedCore/ Enjoy!

Thanks for the reference. The attachment clearly says that I disagree with your understanding Khurram. The statement says to consider estimated maximum axial force but it doesn't say to ignore all other forces neither does it say to design for axial force only. So consider all forces with axial force magnitude as the maximum the column can develop based on its connection to shear wall. Hope this helps. Regarding your other comment, What do you mean by "boost up factors". I think I already replied to this question in my reply above. See quoted text below: If you columns are not dual, you either need to make your shear walls shorter in length (horizontal) or add more columns to bump up frame stiffness. You need to use these load combination based on your provided reference from Taranath Book: (1.2 + 0.2*SDS)D + f1L + OmegaO*E (0.9-0.2*SDS)D + OmegaO*E Whatever you get out of these two load combos, please use them. No need to enhance further as they contain Omega. Thanks.

Khurram, For elements supporting discontinuous systems, special seismic load combinations are used as defined in the building code you are following. For a discussion in special seismic load combinations and UBC please see the following thread: Just run 1.0*Earthquake in both directions to see the percentage of shear distribution between walls and columns and decide if you have a dual system or not. You might also end up with a dual system in one direction and a different system in another direction. Please share more details about this and this is interesting information. Where did you read this? If you columns are not dual, you either need to make your shear walls shorter in length (horizontal) or add more columns to bump up frame stiffness. Thanks.

Areeb, I think you should be able to check it through difference in displacements of adjacent floors. Whats the exact criteria stated in IBC? This requirement can't be in ACI as it is a design code. Thanks.

Khurram's repose is correct however grillage is a term used for steel frame containing beams crossing each other provided under equipment like transformers. tanks etc. Thats because of deformation compatibility. Since both beams have equal geometric stiffness and span, both would be deflecting equally (as what happens in one way slabs where short direction attracts more load). For cases where you have identical beam cross-sections but a shorter beam intersecting a longer beam one, the shorter beam would be governing how much the longer beam would deflect. For cases, where you have a super stiff beam supporting a secondary beam (like a girder or end beam supporting a joist or secondary beam) you can provide "hanger bars". You can check out this thread for more detail: Thanks.

If there are architectural restrictions, go back and discuss with the architect and ask him/her to modify plans to meet your needs. This may or may not work. Generally speaking, You should be able to remove the irregularity without going back to architect. Share your architectural plan and we can suggest something as well. Thanks.