Intro to Design of Modules for Sea and Land Transport Australia

Engineers Australia Victoria Division Senior Engineers Group 24 February 2015

INTRODUCTION TO THE DESIGN OF MODULES FOR SEA AND LAND TRANSPORT TO AUSTRALIAN MINING AND LNG PROJECTS

Presented by: KENNETH A BRACHER BE, FIEAust, CPENG, NPER, RPEQ CONSULTANT DESIGN AND CONSTRUCTION ENGINEER Email: [email protected] Forty years of design and construction experience with Bechtel International, Hatch and RioTinto, on mining, refinery and power projects. Included the design of plant layouts and structures that would enable the offshore fabrication of steel modules in China and Thailand complete with multi discipline equipment, followed by sea and land transport of the modules to the project site for direct installation onto foundations.

CONTENTS 1.0 Introduction, Photos of Modules, Preassemblies, 3D Model Extracts 2.0 Forecast 3.0 Recommendation 4.0 Definitions 5.0 Modules 6.0 Preassemblies 7.0 Precast Concrete 8.0 Impact on Engineering Man hours and Steel Tonnage 9.0 Impact on Schedule 10.0 Sea Transport Structural Design - Dynamic Loading 11.0 Land Transport Structural Design - Dynamic Loading

Introduction to Design of Modules for Sea & Land Transport to Australian Mining & LNG Projects Presentation by Ken Bracher 24.02.2015

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1.0

INTRODUCTION

The 2005-2015 Mining and LNG boom across Australia involved $400 billion of works that in turn lead to the import by sea transport of some 400 major Modules and Preassemblies.

For Mining, Modules and Preassemblies were designed in Australia. For LNG, Modules and Preassemblies were designed in engineering offices in Houston, London, Paris, Tokyo, Mumbai. The experience in Australia has led to the use of Modules up to 1300t. Refer Section 11.0 “Land Transport”

Note that Modules in other Countries can range up to 5000t inclusive of equipment, particularly as demonstrated in the Middle East and India on major refinery and chemical projects.

It needs noting that during the above boom period: 

Module Management experience for Engineers increased.



Module Design experience for Engineers decreased due to the influence of eight major LNG projects.


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2.0

FORECAST  The use of ‘stick build’ on major works will be delegated to minor works, representing some 10% of total steel work.  The use of large imported modules will increasingly be used for the remaining 90% of steelwork, using offshore office engineered designs and offshore steel supply and fabrication.  The use of offshore sourced mechanical equipment, piping, and electrical equipment incorporated in the module, will increase to 90% of total scope.  The use of in situ concrete for foundations will decrease, replaced by imported precast concrete foundations and other units representing up to 40% of total project concrete.


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3.0

RECOMMENDATION

To enable design engineers in Australia to be engaged by offshore EPCM companies on major resource projects, particularly LNG, it is recommended that Australia’s design engineers become well versed in the selection and design of Modules.

This paper presents a range of data that will assist that process.


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4.0

DEFINITIONS

SPMT: Self Propelled Modular Transportation The selection and design of the module structure layout combined with the flexural rubber tyred supported SPMT structure is a critical Load Case Combination process to be modeled and finalized early in the project design schedule.

Requires a joint design effort by the SPMT contractor and the project structural and plant layout design teams, to finalize SPMT details and module structure geometry. Deflection control of the loaded SPMT to 1/1000 is required in order to minimize the creation of column, beam, strut weak axis secondary stresses in particular, and reversal of design bracing tension loads into compression.

Can involve the addition of counterweights to overhangs of the SPMT beyond the Module structure, the addition of vertical and horizontal bracing in the same zone and throughout the module structure. The loading and unloading details of the module on-off the SPMT typically requires a clear distance of 2.5m from road surface to u/s of module base stiffening beams to allow the SPMT to travel into position under the module and to lower the module onto prepared foundations via jacks. Stub columns plus stiffening are incorporated to suit the loading and unloading process. Other load/unload methods have been used but the above is more straight forward and has increased safety.

PAMs: Preassembled Modules up to 1300t in Australia as per earlier notes

PASs: Preassembled Structures up to 300t


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5.0

MODULES

Decreases on site labour at the higher rate. Increases off site labour at the lower rate. Reduces risks associated with project site tasks, especially at remote sites. site tasks contain the most risk. Moving large packages of site work off site reduces the site construction scope, in turn reducing risk to schedule. Creates opportunities to use lower rates for labour and materials in China, Thailand, Indonesia, Malaysia ,Philippines, Singapore. Enables parallel fabrication and off site erection of modules with site works and foundation construction, in turn leading to possible reduction in site completion schedules. Schedule reductions not finally achieved on several projects, however, due to Logistics and Weather issues. Aim for moving 50% of direct man-hours off site as an initial goal; review as module design and scope progresses to increase this %

Use of Modules further enables: 

Reduction in camp sizes and services, and the scale of fly in/out services. Reduction in concerns of sourcing the large numbers of site construction staff required and of the available experience level. Reduction in concerns of construction equipment availability associated with stick build.



Enables construction in harsh environments to continue under cover (Canada).

Use of Modules requires upfront emphasis on the following by Management and Design teams: 

The critical need for early detail interaction between the EPCM design team and the SPMT and Module contractors.



Early involvement by Engineers in plant layouts to derive framing details that will suit land transport on PAMS and tie down locations on sea transport.


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5.0 

MODULES continued IFC sign off at 100% status without further design changes before module fabrication commences. There being limited capacity to incorporate design changes once module fabrication has commenced.



Use of modules require that increased effort be applied by Project to the planning, coordinating and awarding of the supply and delivery to schedule of all equipment and vendor data, and services to be installed in the module at the offsite module fabrication yard.



Agreement by project that use of modules increases steel tonnage by up to 20% and increases indirect hours by up to 25%.


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6.0

A PREASSEMBLY

Contains in built stability, includes an assembly of steel members, complete with flooring, piping, electrical, liners. The significant difference between Modules and Preassemblies being between the weight of each and how they are transported and lifted. 

Modules being up to 1300t in weight are designed to suit use of SPMTs for transport and direct loading onto foundations without use of mobile cranes. Mobile crane usage being limited to offsite formation of the Module.



Preassemblies being up to 300t and designed complete with design engineer certified lifting lugs to suit use of mobile cranes of say up to 600t SWL for lifting into the main structure. Many preassemblies can be in the range of <20t.

The preassembled unit may be part of several preassemblies that comprise a structure. The preassembly may consist of platework and stiffening beams that comprise a lower hopper of a bin. The bin consisting of the lower hopper plus upper bunker. The hopper and bunker preassemblies when connected comprising the total bin .The connection of the two preassemblies may be completed prior to lifting the bin as one unit into position or each preassembly lifted separately and connected in position at height to form the total bin. Depends on crane access, total weight and mobile crane capacity. If the lower hopper is installed first, engineering designs the temporary support steelwork and jacking points to enable the hopper to be raised up to the connections at the u/s of the bunker after the bunker is installed on its supports. All the above requires allocation of further engineering design hours for deriving lifting lugs and stiffening, the addition of steel members, firstly, in the form of cradle steel and stub columns, particularly the lower hopper during transport and, secondly, additional temporary steel to the main structure to suit mobile crane lifting that can in total equate to 15% of the main structure.

Also requires additional site hours and craneage to install then remove on completion all temporary steel where requested by client.


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7.0

PRECAST CONCRETE

All concrete can be precast and shipped to site either with the Steel modules or separately. However the following listing of typical concrete items on a project advises which items to focus on when reviewing whether to precast or not. The percentage of total project concrete to be precast offsite on Mining and LNG projects can be up to 40% of total project concrete.

Pile Caps

No

Major equipment foundations and pedestals

No

Elevated structural slabs

No

Grade slabs

Concrete piling

No. All grade slabs have drainage falls of varying complexity. No. If precast, the resulting many segments require full tension splices of the ring tension rebar up to 4.0m long at each joint using K = 2.0 Yes

Spread footing foundations with pedestals

Yes (up to 4m x 4m x 1m)

Concrete columns

Yes

Grade beams

Yes

Rail and pipe sleeper supports

Yes

Pump plinths

Yes

Transformer blast walls

Yes

Jetty deck beams and planks

Yes

Inground electrical pits, mechanical pits, drainage pits Retaining walls thickener under flow tunnels

Yes

Tank ring beams

Yes


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8.0

IMPACT ON INDIRECTS AND STEEL TONNAGE FROM USE OF

MODULES Increase in steel tonnage

= 20%

Increase in indirect man-hours

= 25%

The above result from: 

The need to design all structures and temporary steel to suit all proposed transport and erection procedures, including where use of SPMTs and sea transport is to be adopted, including the introduction of double columns at module junctions, additional bracing, increased foundation widths at double columns.



The dynamic lateral and vertical loads from sea transport readily exceed project operation loads.

The Canada experience, for example, where construction proceeds during winter by initially constructing braced outer perimeter columns, footings, cladding. internal columns and foundations plus roofing, to enable modules to be delivered direct into the building via the use of SPMTs. This construction procedure can require the building structure to be increased in width and length by some 3m all round.


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9.0

IMPACT ON SCHEDULE AND LOGISTICS

In theory the use of modules leads to possible reductions in project schedule. This Paper recommends that this assumption should not be assumed. Schedule reductions assume that offsite module fabrication and erection will proceed to schedule and all equipment to be installed in the module will be delivered at the same time as project site infrastructure, earthworks, drainage, services and foundations are being constructed.

Several major projects, however, have had equipment deliveries to module fabrication yards delayed to such an extent from a combination of logistical, design and expediting issues, that module departure dates cannot be met: resulting in demurrage charges, logistics and follow on labour utilization issues at project site, disruption to erection logics, the need for further laydown areas to be allocated to avoid chaos at site.

In addition, as the 100% complete of module design rule is now used widely preventing fabrication of modules to proceed at

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10.0 DESIGN FOR SEA TRANSPORT 

Lowther Rolton



Veritas Marine



WMI Science and Engineering

The above consultants provide Sea Transport Reports to the project. Consultant cost can be up to $60,000. Provides recommended dynamic loadings on shipped Modules using wave data and vessel data applicable to the project shipping route. Vessel travel speed of 7 knots max specified.

Sea Transport Load Cases can be: Horizontal Longitudinal Dynamic Force (Pitch) = 0.5g Horizontal Transverse Force (Roll)

= 0.8g

Vertical Force (Heave)

= 0.3g

The maximum roll value in the writer’s experience has been 0.9g for sea transport from New Zealand to Bell Bay, Tasmania.

The minimum value has been 0.6g from Thailand to Gladstone.

Wind speed during sea transport is taken as 20 mps, (safe refuge locations from tropical storms being specified).

Load Combinations DL + Pitch + Vertical + Wind DL + Roll + Vertical + Wind


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11.0 DESIGN FOR LAND TRANSPORT Load Cases HL = Horizontal Longitudinal Dynamic Force

= 0.3g

HT = Horizontal Transverse Dynamic Force

= 0.1g

V = Vertical Dynamic Force

= 0.05g

Add forces for road gradient and cross slope effects Longitudinal up to 7%

= 0.07g

Transverse up to 3%

= 0.03g

Wind load V

= 20 mps

Load Case Combinations DL + HL + V + Slope Forces + Wind DL + HT + V + Slope Forces + Wind

Land Transport routes to be surveyed by project and routes selected to comply with above slope limits, project derived clearance diagrams that arise from module dimensions and from SPMT geometry and properties.

The SPMT axle/wheel loads can generally be approved by Local Road Authorities. The total load of SPMT plus Module load is another issue and can lead to non approval of the SMPT for transport on the proposed route.This outcome needs to be sorted early.

Restricting the Module load to 1300t is a logical start in the early design process as loads of this magnitude on a SPMT has been approved in WA and Qld to date. The best approach is to commence preliminary load estimates and distribution followed by route surveys and reviews with local authorities’ process that in turn will converge to finalizing the permissible route, load distribution, and maximum permissible Module load. Can readily result in limiting the Module load to less than 1300t.

All this coordination needs sorting well before major modeling of the combined SMPT structural plus Module structural geometry and sizing is progressed too far, to avoid rework.

End of Paper


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Intro to Design of Modules for Sea and Land Transport Australia

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