What does a structural engineer do in oil and gas projects?

I. Core Responsibilities — Structural Engineer (Oil & Gas)

Executes structural design, analysis, verification, and life-cycle integrity for onshore and offshore oil and gas assets.

• I.1 Perform concept, FEED, and detailed structural design for jackets, topsides, modules, FPSO/LNG topside skids, pipe racks, substations, compressor buildings, subsea frames (PLEMs, PLETs, manifolds), and foundations.
• I.2 Build and validate analytical and finite element models (beam, shell, solid; linear/nonlinear; static, dynamic, buckling, fatigue) to verify strength, serviceability, and stability under combined loads.
• I.3 Define design basis: load cases, combinations, partial factors, environmental contours, return periods, and limit states per applicable codes (e.g., ULS, SLS, FLS, ALS).
• I.4 Calculate environmental and operational loads: wave, current, wind, seismic, blast, thermal, imposed, lifting, transport, load-out, installation, ice, and accidental (ship impact, dropped objects).
• I.5 Size members, connections, bracing, stiffening, and joints; specify materials, corrosion allowance, protective systems, and weld categories/fatigue classes.
• I.6 Execute fatigue screening and detailed fatigue life assessments; propose redesigns or mitigation (thickness/local details, weld improvements, sleeves/ clamps).
• I.7 Develop temporary works: sea-fastening, grillage, lift points, spreader bars, rigging checks, transportation accelerations, and yard handling procedures.
• I.8 Produce and check calculations, design notes, datasheets, specifications, MTOs/BOMs, and AFC/IFC drawings in collaboration with designers/modelers.
• I.9 Support constructability, fabrication, and site queries; participate in model reviews, Hazids/HAZOPs for structural threats, lifting/installation readiness, and risk assessments.
• I.10 Conduct structural integrity management (SIM): anomaly assessment, fitness-for-service, life extension, RBI inputs, repair design, and inspection scopes.
• I.11 Interface with geotechnical for piles/soils and naval/marine for hydrodynamics and installation; manage technical interfaces with piping/equipment to control loads and penetrations.
• I.12 Prepare technical requisitions, vendor data reviews, and deviation assessments for structural items (steel, gratings, fasteners, modular skids, bolting, elastomeric pads).
• I.13 Participate in third-party verification, classification/certifying authority compliance, and technical audits; close actions and non-conformities.

II. Required Skills and Demands

II.A Technical Skills

• II.A.1 Structural analysis and design: beams, frames, plates, shells; stability, second-order (P-?/P-d), geometric/material nonlinearity, contact, local buckling.
• II.A.2 Offshore hydrodynamics loads (Morison/ diffraction), wind/seismic/blast load derivation, thermal/settlement/vibration serviceability checks.
• II.A.3 Fatigue and fracture: S–N curves, detail categories, SCFs, notch effects, Miner’s rule, crack growth fundamentals for life extension.
• II.A.4 Steel design and detailing to major codes; weld design, bolted joints (preloaded/non-preloaded), slip-critical connections, corrosion allowances.
• II.A.5 Foundations: piles, suction caissons, shallow foundations, grout details; soil–structure interaction in collaboration with geotechnical.
• II.A.6 Temporary works and installation engineering basics: lifting, load-out, transportation, load path verification, MWS interface.
• II.A.7 Brownfield modifications: tie-ins, hot work constraints, live-plant risks, SIM and anomaly criticality grading.
• II.A.8 Codes/standards literacy: API, ISO 19900-series, DNV, NORSOK, AISC/Eurocode, ASCE, AWS, ACI for hybrid concrete elements where applicable.
• II.A.9 Data handling and QA: calculation traceability, model verification/validation, peer reviews, interface control.

II.B Soft Skills

• II.B.1 Clear technical writing and drawing mark-ups; ability to defend calculations in design reviews.
• II.B.2 Cross-discipline coordination with process, mechanical, piping, E&I, marine, procurement, construction, and inspection teams.
• II.B.3 Risk-based decision making, schedule awareness, and change control.
• II.B.4 Mentoring junior engineers; constructive checking culture.

II.C Physical/Field Demands

• II.C.1 Yard/offshore visits; climbing ladders/stairs, confined spaces, heat/humidity or cold, and PPE use.
• II.C.2 Offshore survival and medical certifications for site work (e.g., BOSIET/FOET/HUET equivalents; region-dependent).
• II.C.3 Periodic travel to fabrication yards, offshore assets, and vendor premises.

II.D Key Formulas Used

• II.D.1 Bending stress: $$\sigma = \frac{M}{Z}$$; combined Von Mises: $$\sigma_v=\sqrt{\sigma_x^2+\sigma_y^2-\sigma_x\sigma_y+3\tau_{xy}^2}$$
• II.D.2 Euler buckling: $$P_{cr}=\frac{\pi^2 E I}{(K L)^2}$$
• II.D.3 Morison wave loading on slender members: $$F(t)=\tfrac{1}{2}\rho C_D D |u|u + \rho C_M \tfrac{\pi D^2}{4} a$$
• II.D.4 Wind dynamic pressure: $$q=\tfrac{1}{2}\rho V^2$$; inertial transport load: $$F=m a$$
• II.D.5 Fatigue (S–N, Miner): $$N=\left(\frac{C}{\sigma_a}\right)^m,\quad D=\sum_i \frac{n_i}{N_i}\le 1.0$$
• II.D.6 Natural frequency (single DOF): $$f_n=\frac{1}{2\pi}\sqrt{\frac{k}{m}}$$
• II.D.7 Weld throat shear (fillet): $$V=0.707\,t\,L\,\tau_{allow}$$

III. Typical Tools, Software, and Equipment

• III.1 Global/frame analysis: SACS, STAAD.Pro, SAP2000, RFEM, SESAM.
• III.2 Finite element analysis: ANSYS Mechanical, ABAQUS, NASTRAN; local shells/solids, contact, nonlinear buckling.
• III.3 Offshore dynamics/fatigue: SACS fatigue, SESAM/USFOS, OrcaFlex (coupled riser/mooring loads interface).
• III.4 CAD/BIM and detailing: AutoCAD, AVEVA E3D/PDMS, Smart 3D, Tekla Structures, Navisworks for model reviews/clash checks.
• III.5 Calculation and scripting: Mathcad, Excel/VBA, Python/NumPy for custom checks and data wrangling.
• III.6 Geotech/foundation interfaces: GRLWEAP or in-house pile capacity tools (via geotechnical team inputs).
• III.7 Field tools: NDT gauges (UT/MT/PT coordination), total station/laser scanning data review, torque/bolt tensioning specs.
• III.8 Standards libraries: API RP 2A/2SIM/2MET, ISO 19901/19902/19906, DNV-ST/GL-RP series, NORSOK, AISC/Eurocode, AWS.

IV. Work Environment

• IV.1 Onshore engineering office with periodic travel to fabrication yards and operating sites.
• IV.2 Offshore exposure for surveys, brownfield tie-ins, and construction support; typical short hitches (e.g., 7–14 days) as needed.
• IV.3 Schedule: standard 5–2 office cadence; compressed schedules during model freeze, IFC, and installation windows.
• IV.4 Travel: project-dependent, ~10–30% across design reviews, yard inspections, MWS meetings, and offshore campaigns.

V. Reporting Lines and Cross-Functional Interfaces

• V.1 Reports to: Structural Lead/Principal or Engineering Manager (project or discipline).
• V.2 Internal interfaces: process, mechanical, piping stress/layout, E&I, instrumentation, safety/technical safety, marine/naval, geotechnical, metocean, procurement, project controls, QA/QC, construction/fabrication, commissioning.
• V.3 External interfaces: certifying/class authority, marine warranty surveyor, third-party verifiers, fabricators, equipment vendors, survey/inspection contractors.
• V.4 Handoffs: calculation packages, marked-up models/drawings (AFC/IFC), MTOs, technical specifications, and responses to site queries (RFIs/TQs).

VI. Career Ladder and Progression

• VI.1 Structural Engineer ? Senior Structural Engineer ? Lead/Principal Structural Engineer ? Structural Discipline Lead/Technical Authority ? Engineering Manager/Project Engineering Manager.
• VI.2 Lateral specializations: offshore dynamics/fatigue specialist, brownfield/SIM specialist, installation/temporary works, blast/seismic specialist, subsea structures specialist.
• VI.3 Advancement enablers: delivery of full life-cycle packages (concept ? fabrication ? install), chartered/PE status, consistent design reviews, and successful yard/offshore turnovers.