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OFFSHORE OFFSHORE STRUCTURAL DESIGNSTRUCTURAL DESIGN

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Introduction Introduction

• Define the subject matterDefine the subject matter• Design philosophy;Design philosophy;

Taguchi’s theory of robust design; Deming’s Taguchi’s theory of robust design; Deming’s principles of quality control; Quality Function principles of quality control; Quality Function Deployment; Design for Manufacture; Concurrent Deployment; Design for Manufacture; Concurrent Engineering; etc.Engineering; etc.

• Accuracy of Factor of Design (LRFD v WSD)Accuracy of Factor of Design (LRFD v WSD)• LEAN APPROACH TO DESIGNLEAN APPROACH TO DESIGN• R4D – Research for DesignR4D – Research for Design• AEE - Advanced Engineering EnvironmentAEE - Advanced Engineering Environment

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Generic mechanical engineering design processGeneric mechanical engineering design process

START

Recognition of a need

Definition of the problem

Design synthesis

Evaluation of preliminary designs

Detailed design

END

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OFFSHORE FIELD DEVELOPMENT PLANOFFSHORE FIELD DEVELOPMENT PLAN

ACQUIRE

EXPLORE & APPRAISE

DEVELOP

OPERATE

DECOMMISSION

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Feasibility Studies

Preliminary Design

Final Design

Reservoir Management

Drilling & Well Plans

FacilitiesPlatform

Offtake

Economics

External Constraints

Environmental Criteria

Offshore Development Design Spiral

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DESIGN WORK;DESIGN WORK;ancient structures, ancient ancient structures, ancient thinkingthinking

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DESIGN WORK;DESIGN WORK;recent past offshore structuresrecent past offshore structures

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DESIGN WORK;DESIGN WORK;modern thinkingmodern thinking

Detailed Design

Design Synthesis

AEE

Need Recognition

LEAN DESIGN

R4D

Evaluation&

Selection

Problem Definition

Preliminary Designs

Continuou

s Learning

CL

AS

S

ST

AN

DA

RDTEAM

WORK

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OFFSHORE STRUCTURESOFFSHORE STRUCTURESMajor Classes of Loads Considerations

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TUBULAR JOINT DESIGNTUBULAR JOINT DESIGN

• Design Methods LRFD; WSDDesign Methods LRFD; WSD

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LRFD DNV OS C101LRFD DNV OS C101

• Load & Resistance Factor Design:Load & Resistance Factor Design:deterministic based, data gathered by observation of model testing or monitoring deterministic based, data gathered by observation of model testing or monitoring of full size structureof full size structure

• Limit States:Limit States: ULS, FLS, ALS, SLSULS, FLS, ALS, SLS

• Structural element design Ref. DNV OS C401Structural element design Ref. DNV OS C401

• Fatigue Ref. DNV RP C203Fatigue Ref. DNV RP C203

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WSD DNV OS C201WSD DNV OS C201

• Working or Allowable Stress Design:Working or Allowable Stress Design:deterministic based, data gathered by observation of model deterministic based, data gathered by observation of model testing or monitoring of full size structure; sensitive fatigue testing or monitoring of full size structure; sensitive fatigue analysis necessaryanalysis necessary

• Joints to be designed to minimise stress concentrations and Joints to be designed to minimise stress concentrations and reduce complex stress flow patternreduce complex stress flow pattern

• Structural element Ref. DNV OS C401Structural element Ref. DNV OS C401

• Fatigue Ref. DNV RP C203Fatigue Ref. DNV RP C203

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Summary Offshore Summary Offshore EngineeringEngineering

• Offshore engineering is a process of group Offshore engineering is a process of group activity and it brings together a large activity and it brings together a large number of expertise in order to fulfil it’s number of expertise in order to fulfil it’s objectives.objectives.

• The aims of structures & structural The aims of structures & structural element design are:element design are:

1.1. Sustain loadsSustain loads2.2. Maintain acceptable safetyMaintain acceptable safety3.3. Posses adequate durabilityPosses adequate durability