The structures that make permanent construction possible — and the risk that comes with them
Definition
Temporary works are structures, systems and installations erected specifically to support construction operations and removed once the permanent works can stand independently. They include falsework supporting formwork for concrete pours, scaffolding providing access and working platforms, propping systems stabilising excavations, launching gantries erecting bridge segments, strand jack frames supporting heavy lifts, and bracing systems providing stability during erection. Temporary works do not form part of the permanent structure but are essential to its construction.
The defining characteristic of temporary works is that they carry loads that the permanent structure will never see in its service life. A falsework system supporting a bridge deck during a concrete pour may carry the full wet weight of the concrete plus construction equipment — a combination far exceeding the traffic loads the finished bridge is designed for. A strand jack frame carries the full weight of a roof structure being lifted in a configuration that the permanent roof, once in place, will never replicate.
This is why temporary works design is a specialist discipline and, in many jurisdictions, a legally separate design obligation from the permanent works.
Scope and Types
Falsework supports formwork during concrete pours. It must carry the weight of wet concrete, formwork, construction equipment and live loads from workers, and transfer these loads to the ground or the permanent structure below.
Launching gantries are the primary erection equipment for precast segmental bridges, spanning between piers to lift and place segments in balanced cantilever or span-by-span configurations.
Temporary bracing and propping provides stability to structures during erection before permanent connections are made. On steel framed buildings, temporary bracing holds the frame plumb while columns are being bolted and welded. On offshore jacket installations, temporary bracings maintain geometry during load-out and upending.
Marine temporary works include mooring systems for positioning vessels and barges, temporary buoyancy aids for floating structures, and grillage systems for load-out operations.
The Commercial and Risk Dimension
Temporary works failures are disproportionately represented in major construction collapses. The Loddon Viaduct falsework collapse in 1972 is a recognised example of the consequences when temporary works loads are underestimated. It directly influenced the development of UK temporary works practice, leading to BS 5975-1:2024 (management procedures) and BS 5975-2:2024 (falsework design) — the codes that govern temporary works design and management today.
The approval chain for temporary works designs — contractor, designer, client checker, independent verifier — is a principal source of sequence delay on major projects. Each link in that chain adds days to the critical path. And on projects where erection plant is mobilised at day-rate, those days have a known and specific cost that the approval chain rarely sees.
Tap to enlarge
Temporary works — definition, scope and types, load path and approval chain
Original diagram — EE&HL Network 2026 · In preparation
Diagram: Original — EE&HL Network 2026
Tap to enlarge
Temporary works load path — falsework, erection plant interface and permanent works transfer
Original diagram — EE&HL Network 2026 · In preparation
Diagram: Original — EE&HL Network 2026
Frequently Asked Questions
Temporary works are structures, systems and installations erected specifically to support construction operations and removed once the permanent works can stand independently — including falsework, scaffolding, launching gantries, strand jack frames and bracing systems.
Temporary works carry loads the permanent structure will never see in service — wet concrete weight, erection plant loads, construction live loads. These require separate design, independent checking and a defined approval chain before work can proceed.
The approval chain for temporary works designs is one of the largest sources of sequence delay on major projects. Each link adds days to the critical path while erection plant accumulates standby cost at day-rate.
