prior to the casing of the pile cap and pump pads to determine the maximum pile reactions. The nomi- nal pile diameter is 750mm and pile length is 20m. Upon installation, the pile head is treated as free headed in the analysis. The allowable pile compression capacity in this case is (P) Cap =2200 KN and shear capac- ity (Q H ) Cap =240 KN. The maximum pile lateral deflection was limited to 6mm. After casting the concrete pile cap, the pile head is restrained against rotation and lateral capacity for this condition is (Q H ) Cap =145 KN. Pile group reduction factor is 1.65. For erection conditions, the maxi- mum SLS column reactions are axial compression (P max =182 KN, maxi- mum shear reaction (Q) max =9 KN, and maximum tension (T) max =0. For operating/testing conditions, (P) max =227 KN, and (Q) max =11.5 KN. Figure 7b shows section A-A to illustrate the interface of the pump skid with the concrete pile cap. The maximum FE bending moment is 80 KN-m/m. Recommended top and bottom reinforcements are 25M @ 200mm (each way). The concrete shear resistance is 791 KN, which exceeds the maximum factored pile loads = 227 KN. The vertical pile reinforcements must be projected into the pile cap, as shown. Figure 7c shows section B-B through the pile. The recommended longitu- dinal reinforcement is 20-30M, and spiral reinforcement is 15M @ 200mm. Conclusions Current design guidelines for natu- ral gas processing plants overlook critical structural aspects. This arti- cle describes cost-effective meth - odologies to design the steel and concrete members required in natu- ral gas processing plants. Simplified models are described to idealise load transfers. Horizontal and ver- tical springs along the pile length simulate soil structural interactions. Numerical results were discussed for the design of pumps and com- pressors located at the BTU. Results also presented modular steel struc- tures required in the BTU. The procedures are computationally effi - cient and can be used by the oil and gas industry.
A
B
1
2
3m
7m
Z
A
5.5m .5
5.5m .5
Y
1
2.5m .5
3.5m
3.5m
B
B
3m
X
(b) Section A-A ( ) ti -
12m
Figure 6 PCH geometric details
3m
beam vertical deflection is calcu - lated as (δ max ) =9.1mm. The allow- able beam vertical deflection is (δ v ) =16.75mm. The maximum sway deflection was found as (δ H ) Max =16mm. The allowable sway deflec - tion was limited to (δ H ) Limit =20mm. The maximum unity index (UI) SLS =0.54 and (UI) ULS =0.47. It is recommended to use the PCH support system shown in Figure 7a to reduce deflections and vibration during operation. The size of the concrete pile cap is 4m (W) x 13m (L) x 0.6m (t) and was modelled using 1300 shell elements. The steel framing of the PCH at (Z)=0 is par- tially embedded in the concrete. The numerical FE model was first analysed for erection conditions
A
A
2.5m .5
X
( )
(O)
A
(a) Plan ( ) l
3m (W) x 12m (L) x 3.5m (H). The base framing at Z=0 is embedded in concrete foundations. Pumps are seated on four steel frames bolted to the base skid. Figure 6b shows the structural elevation of section A-A along grid line 1. The two frames are separated by 1m and each side contains two pumps. The pump house was analysed using Finite Element for erection, oper- ation, testing, and transportation load conditions. The maximum
1
2
3m
Y
25M @ 200mm
25M @ 200mm
3m
0.6m
B
15M @ 200mm
A
A
B
B
7m
(b) Section A-A
15M @ 200mm
A
20-30M
3m
X
(c) Section B-B
(a) Pile-cap layout
4m
Figure 7 PCH Support plan and details
36 Gas 2022
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