onshore metal structures for shtokman project

Presented on 12 November during Metal Expo exhibition 2009, Moscow

Shtokman LNG plant and terminal

Structural Steel


On Shtokman Onshore, the following steel structures are identified:

Modules (Process, interconnecting) built in a construction yard anywhere in the world - and transported to Teriberka site

Stick-built structures (Pipe-racks, shelters), prefabricated on a construction yard and reassemble at site - preferably field bolted

Marine facilities built on site (Site welded) One 170m height Flare structure - prefabricated on a construction

yard and reassemble at site

Modularized strategy, where possible, is justified by:

Harsh environment for construction Construction window that exclude most of the winter season

Steel Structures General Presentation


Typical Module Skeleton Overview


Overall Sizes:

Average (each): Length= 40m, Width= 20m, Height= 30m The smallest: Length= 18m, Width= 15m, Height= 18m The biggest: Length= 50m, Width= 36m, Height= 32m

Dry Gross Weights (Total including structure, equipment, piping etc) :

Average (each): 4000 metric tons Lightest: 500 metric tons Heaviest: 8500 metric tons

Structure Similar to offshore structures, generally sized by the pre-service phases such as sea-transportation

Main Modules


Typical Interconnecting Module Structure


Overall Sizes:

Average (each): Length= 30m, Width= 12m, Height= 10m The smallest: Length= 30m, Width= 12m, Height= 8m The biggest: Length= 54m, Width= 12m, Height= 14.5m

Structural Gross Weights:

Average (each): 170 metric tons Lightest: 80metric tons Heaviest: 270 metric tons

Structure Similar to offshore structures, generally sized by the pre-service phases such as sea-transportation

Interconnecting Modules (= few km of Modularized Pipe racks)


Pipe racks

Shelters

One 170m height Main Flare (800metric tons structure)

Marine facilities

Various skids and packages

Stick Built Structures

Other Structures

Miscellaneous Structures


LNG Train Pipe Rack Overview (Stick-Built)


Typical Process Pipe Rack Overview (Stick-Built)


Typical Shelter + Stick Built Structure


Typical Shelter Overview (Stick Built)


General Philosophy: Double Compliance

At design level and for Structural engineering, double Verification is required, i.e. Compliance with:

International standards Russian Standards (in-service phase, as a minimum)

Steel selection shall fulfill the same philosophy Compliance with both regulations - especially in terms of temperature

requirements

Procurement shall be practical from all countries

Structural steel Material


Material selection Temperatures: Statically, few days below -20C during the year

Annual Lowest Mean Daily: -26.5C 10 Year Return Period Lowest Temperature: -33.1C 100 Year Return Period Lowest Temperature: -39.0C

Modules are mostly designed by pre service phases such as sea-transportation and load-outs (i.e. with Tstatistically > -20C)

Stick-Built Structures will have to withstand design loads combined with design temperature: E.g.: -26.5C

In that respect, ECA was conducted in order to demonstrate that conventional offshore steel (e.g. KT-40) is suitable for most of the plate thicknesses envisaged, in order to limit procurement of some special "arctic quality" steel.

Target maximal thickness: 50mm



Strategy implemented is aimed to avoid difficult sourcing for most of steel plates and sections used in structures.

Material selection Requirements:

As per SNIP II-23-81 and GOST 27772-88 Site Location: Zone II5 (Design Temperature > -30C)



Structural steel Material Russian Standards

Structural steel Material International Standards


Structural steel Section Russian Standards

Structural steel Section International Standards


Example of equivalence tables between Russian and International standards

onshore metal structures for shtokman project

Documents