A
Structural design calculations
Load cases, analysis and member checks for each structure type.
Discipline · detailed engineering
Civil & Structural Design & Engineering
Site grading, steel structures, foundations, buildings and site works for substations, pooling stations, BESS sites and HVDC station yards, designed from the approved layout, equipment loads and geotechnical data.
Section 01
Design basis and information inputs
Civil and structural design depends on information that arrives from several directions, so the first step is to list what is needed and who supplies it. We work from the approved general arrangement or layout; the wind and seismic zone and the loads the client specifies; the geotechnical report with bearing capacities and founding levels; architectural and building requirements; equipment terminal loads and dimensions; anchorage and foundation reaction schedules from vendors; the structural codes the client and national practice require; and drainage and grading constraints for the site.
Inputs that are missing or still preliminary are recorded in an interface and input register with the date each is needed. Design is not advanced on unconfirmed data without the assumption being written down and agreed.
| Input | Typically from |
|---|---|
| Approved layout and GA | Electrical design |
| Wind and seismic criteria | Client specification |
| Bearing capacity, founding levels | Geotechnical report |
| Equipment loads and dimensions | Vendor drawings, GTP |
| Building requirements | Client, architect, services |
| Survey levels, plot plan, drainage constraints | Site survey, client |
Section 02
Switchyard structures
Switchyard structures carry conductors, equipment and lightning protection: steel gantries, towers and line termination structures, equipment support structures, bus support and portal structures, lightning masts and shield-wire supports. Loads come from the electrical design (conductor tensions, equipment weights and terminal loads, wind and, where relevant, short-circuit forces) and are combined into load cases under the project code: dead and imposed loads, wind, seismic, conductor tension, short-circuit forces, and erection and maintenance loads.
We size members and connections, design bolting and base plates, check load combinations, and prepare analysis models for review. Where fabrication and erection drawings are assigned, we produce them from the same model so the drawings match the calculation.
Structures
- Steel gantries, towers and line termination structures
- Equipment support structures
- Bus support and portal structures
- Lightning masts and shield-wire supports
Design work
- Member sections and connections
- Bolting and base plates
- Load combinations
- Analysis models
- Fabrication and erection drawings, if assigned
Section 03
Foundations and RCC
Foundations include those for transformers and reactors; isolators, circuit breakers, current and voltage transformers and arresters; equipment support pedestals; gantry and tower footings; control building foundations; and cable trench or cable bridge foundations.
Footings and pedestals are designed for bearing, uplift, overturning and sliding against the allowable soil pressures in the geotechnical report, with settlement considered where the inputs allow. Anchor bolts and embedments are designed with the foundations. Reinforcement details, schedules and bar bending schedules are prepared when they are in scope. Foundation bolt positions and oil pit dimensions follow the approved vendor drawing, which is why vendor data are verified before foundation drawings are issued.
Section 04
MCR, control room and GIS buildings
For the main control room (MCR), relay or GIS building, we prepare the general arrangement, architectural layout as required, and the structural design of the frame: foundations, floors, columns and beams, slabs and roofing. Equipment rooms, cable entries, trench penetrations and openings are coordinated with panel and cable layouts, and the building layout follows the approved architectural and services information.
Building utilities such as HVAC, fire protection, plumbing and building electrical services are designed by their specialists. We take their requirements as inputs and coordinate the openings, loads, supports and architectural interfaces they need.
- General arrangement and room layout
- Roof, beam, slab, column and footing design
- Equipment room and cable entry interfaces
- Trench penetrations and openings
- GIS building slab, crane and embedded item interface
Section 05
Civil infrastructure and site works
Site works tie the yard together: grading and earthwork, drainage and rainwater networks, cable trenches and duct banks, roads and paving, transformer oil containment, bund and sump arrangements as specified, retaining works where levels require them, fencing and boundary walls, yard facilities, and the equipment access that lets the station be operated and maintained.
These drawings are checked against the electrical layout, so that a trench does not cross a foundation and a road does not leave a transformer without access for delivery or maintenance.
- Site grading, plot plan and earthwork
- Drainage, rainwater and stormwater network
- Cable trenches, duct banks and crossings
- Roads and paving
- Oil containment, bund and sump, as specified
- Retaining works, where levels require them
- Fencing, boundary wall and yard facilities
- Equipment access and operability interfaces
Section 06
Civil works by infrastructure type
| Infrastructure | Civil and structural focus |
|---|---|
| AIS/GIS substations | Gantries, equipment supports, transformer and reactor foundations, control and GIS buildings, trenches, roads, drainage |
| Pooling substations | Pooling transformer foundations and oil containment, MCR building, collector cable trenches, grading |
| Solar and wind plants | Inverter and transformer skid foundations, cable trenches, roads and drainage, as contracted |
| Battery energy storage | Container and PCS foundations and plinths, cable trenches, drainage, access for maintenance and emergency |
| HVDC stations | Converter transformer foundations, firewalls, oil containment, yard structures and buildings, as contracted |
Section 07
Output categories
Five groups of outputs. A package may include some or all, depending on the scope agreed.
B
Foundation calculations
Bearing, uplift, overturning and sliding checks against the soil data.
C
GA, layout and infrastructure drawings
Structure GA, foundation layout, trenches, roads, drainage and site plans.
D
Detail and reinforcement drawings
Reinforcement details, bar bending schedules and member schedules.
E
BOQ, MDL and coordinated issue set
Material estimates, the civil MDL and, where approved, a coordinated set issued for construction.
Section 08
Design interface examples
| When this changes | This is affected |
|---|---|
| General arrangement or equipment position | Foundation centre-lines, levels, trench routes |
| Conductor tension, wind or short-circuit loads | Gantry member sizes and footings |
| Transformer or equipment vendor drawing | Foundation bolts, plinth, oil pit dimensions |
| Geotechnical report or founding level | Foundation type, depth and reinforcement |
| Cable routing | Trench layout and control room penetrations |
Interfaces are tracked in a register so that a change in one document is traced through the drawings that depend on it.
Section 09
Review workflow and scope limitations
Confirm inputs
Record the approved layout, soil data, loads and criteria.
Design and calculate
Prepare structural and foundation calculations.
Interface check
Check electrical, vendor and geotechnical data against the design.
Internal check
Independent check of calculations and drawings.
Submit
Issue for approval in the client’s convention.
Comments and revisions
Respond through the CRS and issue revised documents.
Scope limits. Site survey and soil investigation are normally supplied by others, and the design relies on their accuracy. Site supervision is contracted separately where needed (see site support). Quantities are estimates from the issued drawings, not measured work.
ISSUED FOR APPROVAL
Submitted for the client’s or consultant’s review. It is a proposal for acceptance, not an approved document.
APPROVED
The formal response of the approving party, which may carry comments. Only the client, owner’s engineer or consultant can give it.
ISSUED FOR CONSTRUCTION
Released for use at site, in the status and under the convention the project defines. Revision labels differ between projects.
Related
Submit your SLD, GA, geotechnical data and civil MDL
Send the approved layout, the geotechnical report, the equipment drawings and the civil deliverable list. We will confirm the inputs we still need and a sensible submission sequence.