Design Criteria for Horizontal Equipment

1. Wind Load:

  a). Basic diameter = diameter O.D. + 2 ( shell thickness + insulation).
    effective projected area = height x I.F. x basic diameter.

  b). Intensification Factor (I.F.):

    Diameter ≤ 760 mm, I.F. = 1.50
    Diameter 900 to 1350 mm, I.F. = 1.40
    Diameter 1370 to 1960 mm, I.F. = 1.30
    Diameter 1980 to 2570 mm, I.F. = 1.20
    Diameter ≥ 2590 mm, I.F. = 1.18

  c). The vessel saddle to pier connection shall be considered fixed for transverse loads.

  d). Longitudinal winds shall be resisted by the fixed end pier only.

  e). The force required to remove tubes from heat exchanger shall be 100% of bundle weight, but ≥ 19kN.


2. Load Combinations:

  Empty Load (or Erection Load) + Wind (Seismic)
  Operating Load + Temperature + Live Load
  Operating Load + Wind (Seismic)
  Operating Load + Temperature + Wind (Seismic)
  Operating Load + Temperature + Live Load + Wind (Seismic)
  Test Load
  Test + 0.5 Wind (Seismic)
  Empty Load + Bundle Pull Load (applies to supports only)


3. Sliding Plates:

  Teflon plates are normally 25 mm smaller than the length and width of the saddle base leaving 12.5 mm margin all around.

  Vessel support and top Teflon plate shall have horizontal slotted holes to allow movement due to expansion and contraction.


4. Pier Design:

  Pier shall be designed as cantilever columns, k = 2.0.

  Pier width ≥ 10% of height or 300 mm, minimum concrete cover for anchor bolts shall be 100 mm.

  Normally, pier dimensions = saddle support base plate size + 100 mm.

  A double tie shall be placed at top of piers spacing 50mm and 125mm below top of concrete.

  Minimum vertical reinforcement = 0.25% times gross section area.


5. Footing Design:

  The common footing is used for pier spacing ≤ 4m.
  Use two separate spread footing when pier spacing > 4m, tie beam may be used.


6. Normally, the stability ratio is ≥ 1.5 for sliding and overturning.


7. Soil Bearing:

    e ≤ a/6     B.P._max = P/a [1 + 6e/a]         B.P._min = P/a [1 - 6e/a]
    e > a/6     B.P. = 2P / [3a(a/2 - e)]

بارهای سازه

Structural Loads

Ultimate Limit States (ULS) ----------------include exceeding the loading-carrying capacity, overturning, sliding, and fracture.

Serviceability Limit States (SLS) ---------include deflection, vibration, permanent deformation and local structure damage such as cracking.

  D ...... Dead load - a permanent load dure to the weight of building components.
  E ...... Earthquake load and effects - a rare load due to an earthquake.
  H ...... a permanent load due to lateral earth pressure.
  L ...... Live load - a variable load due to intended use and occupancy.
  P ...... Permanent effects caused by pre-stress.
  S ...... Variable load due to snow, including ice and associated rain.
  T ...... Effects due to contraction, expansion, or deflection caused by temperature change, shrinkage, moisture change, creep, ground settlement, or a combination thereof.
  W ...... Wind load - a variable load due to wind.

Load Combination for U LS

Case	Principal Loads	Companion Loads
1	1.4 D	-
2	(1.25D or 0.9D) + 1.5L	0.5S or 0.4W
3	(1.25D or 0.9D) + 1.5S	0.5L or 0.4W
4	(1.25D or 0.9D) + 1.4W	0.5L or 0.4S
5	1.0D + 1.0E	0.5L + 0.25S

دیزاین فاندشن

Square Foundation Design steps (with Moment)

نوت: در صورت موجودیت مومنت  عن المرکزیت (e)Eccentricity به وجود آمده و به اندازه (e) عمل قوه به سمت x  و y انتقال (shift) می گردد.

Step 1:-

           Calculation of loads = W_T = W_c + W_F = W_c + 10% W_c

Step 2:-

           Calculation of Foundation Area (A) = W_T/p’           p’= Bearing capacity of soil

Step 3:-

           Calculation of upward pressure (p) = W_c /A

Step 4:-

           Calculation of projection 

           a1 = (L-b)/2 + e

           a2 = (L-b)/2 - e

Step 5:-

          Calculation of Depth of Foundation (D)

a)     B.M. consideration :

b)     Punching shear consideration :

a)       B.M. consideration :

(B.M)_max = Resisting Moment

pL (a)²/2 = k b d²  or  Q b d²  

Q=0.185 * f’c *(.09) (permissible stress/Mark of concrete )

d=

D = d + cover + dia . of bars

b)  Punching shear consideration:

Punching load = punching resistance

W_c – pL² = 4 b D q              (q) _all = 10 kg/cm²    D = (W_c – pL² ) / 4 b D q             

Step 6:-

            As = M / fy z              (As)_min = ρ_min b d

Step 7:-

            Nos. of bars:-

            Number of bars = As / Area of selected bars