UmarMakhzumi

Hard to tell from the picture as I have seen such masonry columns with 2" plaster on them.

Waqar, You can define a General Section in SAP2000. It allows you to input all properties manually. See attached.

True, there can be certain cases where UBC gives a higher base shear. However, without knowing basis of study, parameters involved and data points/ no of runs and sensitivity of each parameter quoted results, it hard to conclude. Keeping numbers apart, there are other differences too. IBC considers seismic design category which affects your calculated base shear whereas UBC considers your seismic zone only. While designing a hospital in a lower seismic category, you may end with a higher base shear than for a commercial building with a higher design category, both comparisons being done for IBC. As I said, it is not an apples to apples comparison, and your results can be different based on what parameters you consider. To me, the whole exercise is pointless, because basis are different. Number crunching.

Also, you can apply auto loads based on IBC through ETABS.

I have attached tutorials that will show you how to setup ETABS model for dynamic analysis. Go through all tutorials. There are lucid and self explanatory. OneDrive-2014-03-09.zip

The question posted is related to engineering judgement and what ever you can link with the use of equations and parameters in them. There is no right or wrong answer.

All I can understand from your post is that you are doing a comparison between two codes for Saudi and trying to find out quantitative difference of base shear? Also, I believe you want someone to check your numbers? Before you do that you need to understand the differences between UBC and IBC Seismic Design Philosophy; you aren't comparing apples to apples if you just compare numbers. There is a lot different between two codes. Both codes design to a different Maximum Considered Earthquake (MCE). Considering everything is constant, IBC will give you a higher base shear. Read the attached article:IBC and UBC Comparison.PDF Use the method provided in code to identify your seismic response coefficients. Ss=Ground acceleration at short (0.2 second) period, which will allow you to determine Sms and subsequently Sds. Code outlines the procedure to calculate all these components. I don't know why are you calculating Ss like you did. Documents attached are result output, and calculation is not attached. Without a calculation, no one knows how you came up with the numbers. My best advice to you, to check your numbers is to compare them with a solved example. You can't go wrong.

What kind of column it is? Sketch ?

You might be selecting both ends. Go through all the tutorials if you are starting at ETABS ETABS Watch & Learn

Read this: http://www.sepakistan.com/topic/1307-etabs-load-combinations/?hl=%2Bseismic+%2Bdirection#entry2435 Thanks.

Here http://www.sepakistan.com/topic/1343-seismic-assessment-and-retrofit-design/ It talks about how to model them.

You can do whichever you want to do. It is always good to compare two sets of results. Do you have time history data for a noticeable earthquake in the area where you are designing this tall building?

AQ, you should read Joints in Concrete Construction Reported by ACI Committee 224 to get answers for most of your questions. Here is the abstract of the document: I also recommend having a look at this link.

For the given detail, a stiffener may avert local buckling of flanges or reduce warping, but would not effect LTB Strength. A stiffener doesn't change the unbraced length of beam.

You should always consider all the four cases for seismic with default eccentricity for torsion as a starting point. The only case where you can consider only two cases would be when your building is perfectly symmetrical and has symmetric mass distribution which never happens in commercial design or rarely happens.

I remember this was asked in Nust Masters Exam and is a pretty typical question around. Here is a possibility: 1) C1: Equate weight of column(in terms of height) to compressive stress and find h. 2) C2: Here there are two stresses. Lateral stress of water and compressive stress. Both stresses can be expressed in terms of height and simplified? I am thinking about how would we relate the two expression without complicating things but cant get up my mind ? anyone else can suggest something ? Thanks.

ETABS is a frame analysis program. Apply all loads that you can and what you cant, super impose manually. I agree to Baz.

Use influence lines.

See page 24 of the attached document that shows one way of applying unform load. You can read the whole document too for further information. Ultimate shear tests of prestressed concrete i-beams.pdf

I suppose your material is concret because shear faiulre for steel doesnt make sense in flexural. What you can do is: There are different shear strength models that you can use. E.g., you can do a manual Strut and Tie calclation and compare the results with your FEA. Does your beam has any shear reinforcement or is it a deep beam without reinfo. I did a lab in my masters where we failed a beam without shear reinfo and measured strain values at different location. We verified the results using Canadian Code forumlas that allow calculating shear strenght of beam without transverse reinforcement. For your case, using strut and tie model will be a resonable approach. Give a heads up to your teacher to see what does he say.

Asif, this is a free forum for educational purpose only. We don't allow any advertisements. Any post not related to topic falls under spam and therefore is not allowed. Please review Forum Posting Rules at http://www.sepakistan.com/topic/1344-forum-posting-rules/#entry2660 Thanks.

Okay, Super. Thanks.

You can consider the impact factor and augment your forces for the case of the start and stopping of lift. There would be no significant continuous dynamic forces. I dont have any calculation examples that cover this. If anyone else has that please post. Your supporting members are super stiff axially. I am having a hard time accepting that the operation of the lift would produce any significant dynamic effects in the subject case for reasons explained above. I have designed lift cores considering impact but not any dynamic effects. If you get any examples, do share here too. Thanks.

Yasir, from the above quoted description, I assume that the present wall is a L- Shaped Wall. A reasonable solution for a G + 1 or 2 floor building would be to provide a concrete column at the opposite corner to the L-Shaped wall and connect it with exisiting concrete walls through beams. For G + 1 or 2 floor building that would be sufficient. Similar option should follow for steel. Assuming your present wall configuration is adequate for lateral loads, I see no point in providing steel walls. Depending of the weight of lift and what fdn layout you have, you should be fine with the single column option with beams connectng or bracing into the exisiting wall for concrete/ steel.

I have done masonry calculations where elasticity is a function while caculting the stiffness of the system and effects the center of rigidity. Just saying.