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[swati_mayekar]

Hello All,

I need your help while designing a foundation of a D. G. Set. I am going to design this foundation for first time. It's going to be a pedestal of 2.5m X 6.15m. The depth of footing would be 2 m below G.L. The total STATIC Dead weight of D. G. set is 67 kN. Will there be an addition of any live load (from maintenance people) to this 67 kN?

The challenge in front of me is to design a big column of dimensions 2.5m X 6.15m.

My question is how to model such a big column in any design software?

I just cannot put a single joint load on the top of column (2.5m X 6.15m). Because the D. G. Set will rest on some mountings (at least 4 at 4 corners). Then, in that case, how will I place 4 point loads {Final factored DYNAMIC load FFDL = 1.5X 1.5 X (67 + Live load if any); each point load = FFDL/4} on a single column?

I suppose we don't apply the live load directly on a column. But there will be some movement on this pedestal. Do I need to consider this live load?

Also it would be very useful if someone from you clarifies about how deep one should go for foundation of this D. G. Set. ( SBC is 100kN/m2)


Please clarify my doubts.

With Regards,
Swati Mayekar

[vikram.jeet]

DGset foundation

Pl refer SP 34 IS code,  under Machine foundation ,,

Minimum reinf for block foundation = 25kg/m3

Minimum teinf  at least 12mm dia @ 200c/c on faces as per Sp34

[Arunachalam]

[glnp12]

How do you design the DG foundation of 2.5m x 6.5m as single column ? It is a thick raft supported on founding medium (hard or soft, as per site conditions). Generally, DGs are well balanced engines and mounted on isolators / springs, thus, may not transfer any large dynamic / vibratory loads to the foundation. I feel, for DG of 65kN, size seems to be too large. Normally, such block foundations are used for reciprocatory machines. For DGs, framed structured should be good enough, with natual frequency away for operating frequency of the machine. Loads are transferred through a frame, as UDL along the length and width of the DG. Thus, a raft with soil / rock springs should be better idealization.

[pvgraju]

Dear Sir,

Generally solid element modelling will be done for such type of foundations, columns. Live load can be applied on top slab in the software which will get transferred automatically to columns.

Regards,

P.V.Gavarraju.

[Arunachalam]

For DG set of heavy loads with considerable weight we have to provide pass equaling or little more than 2.5 times the weigh  of Genset.
The disel tank is always on outside when the DG is inside or with Enclosed Canopy type the Full capacity of diesel load  also to be taken as dead weight.  Provide min 0.20 to 0.25 % of reinforcements on all sides including top and bottom.
We provide number of beds like this and all are functioning well  and  not caused any vibration to near by walls.

[swati_mayekar]

Thank you  all !