Assalam o alaikum.
According to ACI 12.5.2,
development length for fc' = 3000, fy=60000, for normal weight concrete and epoxy less reinforcement, The required development length comes out to be
for #3 = 8.2 inch
for #4 = 10.95 inch
for #6 = 16.42 inch
for #8 = 21.9 inch
And if in my case, ACI 12.5.3 is not fulfilled, it means now i have to provide ldh as mentioned above. ldh is STRAIGHT EMBEDMENT LENGTH + RADIUS OF BEND + ONE BAR DIAMETER as shown in figure attached. Now my question is, if in my case, main reinforcement of beam is of #6 and #4, minimum column size required will be 18 inch and 12 inch respectively. Lets say by any means, i can not select #4, #3 bars and size of column where bars are to be terminated is 12 inch, how to fullfil this development length???
I am trying to design shearwalls through ETABS with temperature load applied over shell. At various location, spandral section fails in Shear due to temperature and piers (sometime in shear, mostly in flexure). (See Attached Image)
Certainly all the problem in Shearwalls are due to temperature. I don't want to increase cross section of spandral or pier at some location just due to temperature load case as it will appears non-uniform with rest of the wall.
I have seen stiffness modifier affect distribution of forces and also rigid/semi rigid daiphragm assumption.
Can anybody guide how to properly design the shear wall with temperature load applied in ETABS or share any similar experience. Thanks in Advance.
I WILL LOOSE MY BRAIN FROM ETABS.
I DECIDED TO MAKE MANUAL MESHING FROM AREA ELEMENTS BESIDE EACH OTHER AND EVERY HING WAS FINE .
BUT AFTER DEVISION SAY 7*7 ELEMNTS FOR EVERY BIG ELEMENT AND MAKING ETABS CHECH..................THEN 500 ERROR MESSAGE THAT ALL ELEMNTS ARE CLOSE TO EACH OTHER. WHAT ARE GOING...... SOMEONE TELL ME PLEASE...... I WILL LOST MY WORK
Assalam o alaikum.
I have just designed a frame structure with SMRF. The out put of shear seams weird to me. Column reports design shear Av/s as 0.045. (Images are attached). but when i right click the member, it must show me the most critical case HIGHLIGHTED AUTOMATICALLY. But it highlights load combo 38 (auto-generated combos have been used) which reports Av/s as 0.038. And 0.045 value is at combo 32. Is their any logic behind it?? More over how to interpret this Av/s?? means 0.045 in kip-in units means what? How can i convert this into spacing??
Hello everyone, I hope all of you will be fine. In etabs when we apply Response Spectrum loading on a multistoried building with 2 basement floors. At what floor level this loading will be applied as in equivalent static seismic analysis, we can apply EQX & EQY on any floor we like as this option is available in etabs but the problem is with response spectrum and time history analysis. please if someone knows and have the experince, share it i shall be very thankful.
Salaikom dear professionals,
First of all I would like to express my sincere thanks to the initiators of this forum for establishing such an exceptional atmosphere for knowledge/experience sharing, I it is really useful, In fact since I have found the forum I am mostly online and busy reading the posts. I would also like to thank the members for their professional comments and advice.
As my first post in this forum I would like to ask the following queries:
1-After running the analysis and design when I check the DESIGN DATA through Display >> Show Tables >> DESIGN DATA >> Concrete Frame Output, there is no specific message in Column Summary Data and Beam Summary Data, but in Joint summary data it is showing that “Joint B/C check not done”. Does anyone has any idea? I am sharing the ETABS model for your information and easy reference.
2- ETABS provides greater area of steel in the upper column than the column at BASE, perhaps due to higher moment. Could someone explain why this is so? In practice should we maintain maximum steel in both stories? Or we shall follow what the software suggests?
3- Beside considering the minimum thickness required for deflection control of Beam as per Table 9.a Chapter 9 ACI-318 , using concrete crack behavior in ETABS and checking story drift, Do we have to check the deflection of beams for the serviceability propose elsewhere in ETBAS? If yes, Could anyone explain it?
Regards, and look forward to any explanation
Posting this thread to break the ice. Modelling domes is very easy in Etabs/SAP. All you need to do is to draw the curvature of the dome in elevation by a series of straight lines, but draw only the one half. Then using the apex at centre point, radially extrude the line say 24 times at 15 degree intervals (or 48 times at 7.5 deg intervals. This feature is under Edit> Extrude Lines to areas. You can further use this geometry for Finite Element Analaysis.
I am designing the mosque in zone 4 . The roof of the mosque is a Truss.I have following questions
1. Do truss rest on the beam ? if yes .? do i have to assign any support conditions ? or etab will selelct by default.
2. what will be the grade of steel for the truss ? yield or tensile strength. some one told me go for A 36 ( 36,58)
I accidentally came across these useful case studies, which, I would like to share. You can use them if you are working on a commercial or residential building retrofitting project. These case studies provide insight about seismic retrofitting and also on analytical methods, that are used for building assessment. I would also like to give due credit to people who are involved in these studies. All these studies were performed under a US-Pakistani Joint Cooperation Project. The details for the project are.
6-Storey Mixed Use Building in Karachi.pdf
10-Storey Office Building in Karachi.pdf
RS-4 Storey Academic Building in Karachi.pdf
Five Storey Residential Apartment.docx
Please visit the thread to download the attachments.
*SEFP Consistent Design*
*Doc No: 10-00-CD-0004*
*Date: August 07, 2014*
I am writing this article about a very important, but mostly neglected topic of flexibility of diaphragm. I used to assume that all reinforced concrete slabs can be treated as rigid diaphragms. But as it turns out, only the slab with span-to-depth (depth is length of slab in direction of lateral loads) ratio of less than 3 and without horizontal irregularity can be treated as rigid diaphragm. The more important thing is that the span-to-depth ratio and horizontal irregularity is not the only criteria and one other factor also needs to be kept in mind before assigning rigid diaphragm to concrete slabs in numerical model of building.
Another important concept that I learned, and it was a moment of epiphany for me, is about TRANSFER diaphragms. I had posted a topic “Amplification Of Forces In Etabs” earlier in this forum but we were not able to reach at a satisfactory conclusion. Now, I have the answer to that query: Back Stay effect. Another article is required to explain it , and this concept is not discussed in this article. This article is about flexibility of diaphragm.
Diaphragms are horizontal members of the lateral-force resisting system of building structures. Their function is to distribute inertial forces, generated at its own level, as well as other levels, to vertical members of lateral-force resisting system.
One kind of diaphragm only distributes inertial forces generated at its own level. This kind of behaviour is observed in buildings where there is a continuity of vertical members of lateral-force resisting system: building should not have a setback or podium at lower levels, or below grade levels. The other kind of diaphragm, known as “Transfer diaphragm”,
Read more: http://www.sepakistan.com/topic/1480-diaphragm-flexibility/
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