Mubeen Abid

Hi, I have one tower in Dubai with 2B+G+4Podiums+37 floors, for which I have raft on pile foundation, The piles are bored cast insitu piles, the concrete grade recommended for piles is C60 with waterproofing admixture. Water table for this site is 6m below natural ground level. During the drilling process for piles we encountered water in all pile trenches and the concrete has to be casted in the water as we cannot drain the water, but contractor does not want to use water proofing admixture as ground granulated blast furnace slag (GGBS) is used in concrete mix. my query is 1) Is GGBS enough to act as water proofing agent??? 2) Can we cast concrete with GGBS under water without loss to durability???

Can anyone tell me what will be the density of compost soil?? Give any reference from where I can check?

Thank you Engruzair. As currently I am working in Dubai here most of the designers are using over strength value R=4.5 for RCC structures. This R value 4.5 as per UBC-97 code is for bearing wall system, this is my concern as why they are using this system as they don't have any load bearing wall in their structure.

As salam alaikum, On what basis shall we select lateral force resisting system. If I don't have any bearing walls in my structure than how it will be bearing wall system. Please differentiate between bearing wall and moment resisting system

As salam alaikum, I want to know how to decide the expansion joint thickness in RCC construction.?? Is there any calculation required to decide the thickess?? If yes? kindly tell where I can find the calculation method?

Thanx Mr.Rana, Yes I have Planted columns. No,It is not deep beam the size of beam is 750x900mm. Yes the shear and torsion for beam is OK. No I did not check the wall stresses. Can you guide me how to check these stresses, I mean shall I check these stresses for Special combo?? and what should be the stress limits???

Thanx Mr.BAZ for your reply. So, you mean I should not check wall for special case??? However,Beam is safe in deflection and flexure for special combo.

My column is not floating directly on shear wall, It is floating on beam and that beam is connected to shear wall on one side and to column on other side.

As salam alaikum, Which code we have to use for design of Shear Wall in Etabs(UBC 1997 or ACI 318)?? Also I have shear wall supporting floating column (which is supporting 8 slabs), I have checked this wall for special seismic combination with EQ Load factor of 2.8. It is showing me shear reinforcement of 10,000 mm2,Kindly suggest me how to deal with this condition??

As salam alaikum Dear All, I have a staircase with waist slab 20cm thick,it is casted upto first landing level from ground(First flight). Now,The client wants to increase the floor height,so contractor is proposing to increase the landing slab and waist slab thickness to 40cm from first landing upto floor slab inorder to increase the floor height. Is it allowed to increase the thickness to 40cm with same reinforcement as for 20cm thickness,And also the cover to reinforcement will be 22cm?? Is it OK?? Do I need to check for crack width as I am providing more cover??? Kindly advise...

As salam alaikum, Dear All, I would like to know is it OK to design the beam as fixed beam. For the continous beams with 3-4 spans can we consider the end support as fixed?

Thanx all, Dear Mr Uzair, My building is located in UAE(Dubai) with seismic zone 2B & soil profile type Sc.My material of construction is RCC. I consider R value 3.5 which is for ordinary moment resisting frame system is it correct?? I check one of the previously done project in my office where the designer taken R value 4.5 which is for Bearing Wall system. Kindly advise.

As salam alaikum, Dear all I am designing a B+G+5 building, I would like to know which structural system to use for such structure. I have to take overstrength factor value® from UBC-97 code. What are the basic concept to decide structural system. Thanx.

As salam alaikum, Can anyone explain me how to check uplift of raft foundation in SAFE. And also what are the conditions that leads to checking of uplift for foundation. Thanks.

Mr.Makhzumi, I attached the pdf file..KIndly check.

Dear All As salam alaikum, In my case I have a footing for neck column(This neck column is upto tie beam level only), The tie beam tied to this column is supporting a FLOATING COLUMN. FLOATING COLUMN is resting on the edge of the cantilever of tiebeam. I want to know what moments shall I consider for footing design, shall i take the column bottom moments or shall i take column top moments which is from cantilever tie beam. Kindly provide me your valuable suggestions. For your referrence kindly find attached footing & tie beam layout.Structure.dwg fdn layout.pdf tie beam layout.pdf

As salam alaikum, Dear All, I am doing a G+5 Building, I would like to know about how to check base shear from etabs model and compare manually. To calculate base shear manually i need seismic dead load from model,I want to know how to check this seismic load from etabs model. I have define mass source DL+0.25LL.