Dear Members,

I have vertical vessel with 24.1 bars design pressure, 260 degree celcius , ID = 440mm with 9.53mm thickness and 660mm TL/TL with 550mm half skirt locate at upper/main deck (12.2m to 16.8m). My clients(Shell & Technip)has comment that wind,dynamic and transportation loads and motion effect shall be accordance with their spec.(DEP 37.81.10.31 /API 2A-WSD 21st ED). From spec. given, wind pressure value shall be calculate based on API RP-2A section 2.3.2c with formula for wind drag force is F = (ρ/2)μ^2 CsA;which is F = wind force, ρ = mass density of air(0.0023668 slugs/ft^3 for standard temperature and pressure), μ = wind speed(ft/s, Cs = shape coefficient, A = area of object(ft^2).

As per API RP-2A section 2.3.2e Cs for Cylindrical sections = 0.5,and overall projected area of platform = 1.0.

Also table wind speed and dynamic load as per attachment to follow.
I lack of knowledge to convert information as above to wind pressure.

appreciate if anyone could guide or advice me to solve this problem.

attachment

[size=7]Metocean Design Criteria - In-place
Environment 1000
year
Wave 100
year
Wave 100
year
Wind 100
year
Current 10
year
Wave 10
year
Wind 10
year
Current 1
year
Wave 1
year
Wind 1
year
Current
Waves (m)
Maximum Wave
Height (Hmax) 15.0 13.2 11.4 8.6 11.5 9.9 7.5 9.7 8.3 6.2
Significant Wave
Height (Hs) 8.0 7.0 6.0 4.5 6.1 5.2 3.9 5.1 4.4 3.3
Maximum Wave
Period (Tmax) 12.6 11.8 10.9 9.4 11.0 9.5 8.8 10.0 9.2 8.0
Zero Crossing
Wave Period (Tz) 9.6 9.0 8.3 7.2 8.4 7.2 6.7 7.6 7.1 6.1
Spectral Peak
Period (Tp) 13.5 12.7 11.7 10.2 11.8 10.2 9.5 10.8 10.0 8.7
Wind Speed at 10 m above MSL (m/s) 20.8 3.9
1-hour 21.1 18.9 27. 5.0 16.8 24.0 4.5 14.6
1-minute 29.1 26.1 37.3 6.9 23.2 33.1 6.1 20.2 28.7 5.4
3-second 35.2 31.6 45.1 8.4 28.1 40.1 7.4 24.4 34.8 6.5
Mac.
Current (m/s)
Surface Current 1.43 1.26 1.26 2.10 1.11 1.11 1.85 0.95 0.95 1.58
High and Low Design Water Levels (m)
HSWL 1.4 1.2 1.2 1.2 1.0 1.0 1.0 0.9 0.9 0.9
LDWL 0.3 0.1 0.1 0.1 -0.1 -0.1 -0.1 -0.2 -0.2 -0.2
The above table includes data for associated wind, wave and current conditions. For example, column 3 describes data for the 100-year wind. The 100-year 1 hour wind speed is 27 m/s. The associated maximum wave height (Hmax) for the 100-year wind is 11.4 meters and the associated surface current speed is 1.26 m/s.

The effects of shielding by the skid and/or its equipment may be considered as appropriate.
5.4.2 Dynamic Loads
The dynamic loads (accelerations) to be used in the skid / package design shall be as shown in the following table. These values shall be used for both the operating and storm condition:

Maximum In-Place Accelerations
7 meter significant sea and with associated period of 12.7 seconds in 8 directions including
static heel
Deck Location
Main Deck Upper Deck
Equipment Flare Tower
(1/2 of height)
(%gJ (%g) (%g)
Horizontal (surge/sway) 12 12 17
Vertical (heave) 12 12 12
5.4.3 Transport
Contractor shall design the skid/package for the transportation loads to which the skid/package is exposed between the manufacturing site and the Gumusut Topsides fabrication site. Once the skid/package is installed on the Gumusut topsides it will not be exposed to transportation loads any greater than those loads described in paragraphs 5.4.1 and 5.4.2 above.

Contractor should state in his bid the proposed method of delivery to the Topsides fabrication site.
5.5 PLATFORM CRANE LOADS
A description of each platform crane will be provided by the Principal.

Design loads and moments for local structural framing in the vicinity of platform cranes shall be twice the maximum static rated capacity of the crane and full rated structural strength of the crane. Loads shall be based on the full rated structural strength of the crane, not on the proposed rigging of the crane.

Loads shall be applied for eight boom directions in order to comprehensively size local framing. The crane pedestals and local structural framing in the vicinity of the crane are designed according to API RP 2A for the following load combinations:
■ Dead load (DL) + 2.0 * Safe Working Load (SWL) [API Spec 2C maximum overturning moment (Mmax), maximum thrust (Vmax), and maximum torque (Tmax)];
n DL + 2.0 * SWL [API Spec 2C Mmax with 4% vertical load applied laterally at head sheave] and,
n D.L + 2.0 * SWL [API Spec 2C Vmax with 4% vertical load applied laterally at head sheave

_________________
Faizol
(PV-elite User)