UmarMakhzumi

Shaker, I haven't done walls in years so I am rusty on that. You are right regarding point 2(stated by you) but you need to make sure that for a wall, all piers have same label. Then the forces are reported together. Hope that helps. Thanks.

Why do you have just one joint assigned as support under the wall? The wall should be meshed and supports should be assigned under each node. Thanks.

W/Salaam, The error message is there because of violation of UBC Clause that requires Pu/Po<0.35. I would suggest that you beef up your walls to get the error message clear. Also, have a look at the attached documents. Thanks. Shear Wall Design Manual- Technical Notes.pdf Tall Buildings Shear Walls.pdf

I think you are fine modelling raft at one level. I am not an expert on this. Regarding I am not clear what do you mean by "Model wall at periphery and model slab at bottom? Periphery of pit? Thanks.

The difference is due to the relative stiffness values of the lowest columns compared the the relative stiffness values of the upper columns. The rotational stiffness of the bottom of the lowest set of columns are identical, whereas the rotational stiffness of the upper joints is higher for the middle columns. This makes the difference of the stiffness values of the lower columns less the difference of stiffness of the upper columns. Thanks.

Sohaib, There are two standard ways to work with foundations: ASD and ULS. Please have a look at the two discussions below. The method you should adopt depends upon the codes you are following and recommendations in that code. http://www.sepakistan.com/topic/1519-deduction-of-overburden-from-bearing-capacity/ http://www.sepakistan.com/topic/1700-column-footing-size-for-high-snowfall-areas/ Thanks.

100% SPMDD compaction is achievable. Regarding your second question, I am not aware if the test is applicable to single layers or the whole. Anyway, the recommendations by the geotechnical engineer regarding compaction levels and 200mm thick layer is very standard. If the site is near a river, I would recommend using granular backfill. I can't however comment on the gradation of backfill and perhaps a Civil Engineer would be able to do that. Thanks.

I normally design landing and stairs slab manually. Usually it ends up being one way slab: Wl^2/8. Thanks.

Do you have* piles under your raft or it is grade supported? Thanks.

I don't like the framing. Also, have you tried comparing results when you have a single diaphragm assigned and 2 different diaphragms? Thanks.

Should be for both. Please see: http://docs.csiamerica.com/help-files/etabs/Menus/Define/Section_Properties/Frame_Sections/Auto_Select_Option.htm Thanks.

Please see: http://www.sepakistan.com/topic/1335-design-for-shear-and-torsion-using-etabs/ Thanks.

Normally riser and runs are not modeled. You can calculate the load of riser and run and apply it on the stair slab which mostly is designed as one way slab unless design framing dictates otherwise. Thanks.

Hi Barham, We don't allow links for cracked softwares or warez. Please see forums posting rules at: http://www.sepakistan.com/topic/1344-forum-posting-rules/ Thanks.

Please see forum posting rules http://www.sepakistan.com/topic/1344-forum-posting-rules/ Thanks.

The cracks don't look like yield lines. They are very prominent. I have no idea what could cause them. Definitely not due to flexural. Thanks.

Please see the following posts: http://www.sepakistan.com/topic/1377-when-we-need-dynamic-analysis-and-what-abt-irrgularities/ http://www.sepakistan.com/topic/1357-eccentricity-values-in-etabs/ http://www.sepakistan.com/topic/1683-accidental-torsion/ Thanks.

Good thinking. Your understanding is correct. Thanks.

Modes are deformed shapes. A building may have a primary mode a number of other modes. You can easily check the modes and associated time period by completing a modal analysis and going through the results. For cases where there is a forcing function producing harmonics (like pump, compressor foundations) mass participation becomes meaning less and every mode is important. Under such case we want to design a structure so that none of the modes fall within the frequency of forcing function. If that is unavoidable, we check response of structure under resonance and make sure the amplitudes under resonance are below allowable. For seismic application, mass participation is important. Generally, people ignore modes having less than 5% mass participation for seismic. Thanks.

10m is not a lot. I assume your existing columns are W Sections (I Beams). You can use W310x60 (or the same size as your column) as a trail beam size with bolted connections at end. Now there are different ways you can bolt the beam and columns together. You can provide an End Plate Connection. A 12mm end plate with 4 ASTM A324 Bolts (2 on each side of web) would do. This would be a pin connection. If you want a moment one then you will have to get the beam flange engaged, but do you really need a moment connection? You need to verify this design as I don't know your platform width. Also, like Uzair said, you need to verify existing members. Get a good reference book. Salmon and Johnson is good but little complicated. Kulak and Grondin is the best but its for Canadian Codes. Thanks.

Here is the presentation that highlights the difference between two approaches for foundation design. Thanks. Use of Limit State Design in Foundation Engineering.pdf

Rana is absolutely right. A big no to Risalpur because of location. If you are in Lahore, get a job and do your MS in Structural part-time while working in a design office. If not, then do your MS from NUST while doing job in Islamabad. Dont be too focused on design, rather be open. Thanks.

You are right but structural engineering practise in general is very poor too. Anyway, we can improve on what we can do on our part. Thanks.

Welcome aboard Nasir. Thanks.

Redundancy and continuity are interrelated. However, continuity might not be a good thing in certain cases. One example of that would be where you have T or L -Shaped building in high seismic zones. Continuity in such cases could result in significant torsion. The statement posted is a "sweeping statement" and interpretation varies across different cases. There is no right or wrong answer. Thanks.