Bridge Demolition SWMS

Bridge demolition is one of the highest-consequence activities in Australian civil construction, combining structural collapse risk, working at height over live traffic or rail corridors, heavy crane lifts of partially severed structural members, and exposure to lead-based paint and silica dust from deck breakup. Each sequence — from initial deck saw-cutting, through beam severance and crane-supported lift-out, to pier felling — alters the load path of the remaining structure and can trigger progressive collapse if the engineered demolition sequence is not followed precisely. Under WHS Regulation 2025 this work meets multiple High Risk Construction Work under section 291 triggers, including structural alteration that could cause collapse, work at height above two metres, work near road and rail corridors, and work involving demolition of load-bearing elements. A Safe Work Method Statement is mandatory before any work commences, must be prepared in consultation with workers, kept on site for the duration of the work, and retained for at least two years (or until after any notifiable incident).

Hazards identified

7 hazards covered, sorted by priority.

Control measures

Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.

1. 1Elimination — Where feasible, eliminate in-situ demolition by full span lift-out using tandem cranes during absolute road or rail possession, removing workers from beneath suspended loads.
2. 2Elimination — Remove all non-essential personnel from the demolition exclusion zone established by the demolition engineer; only the lift crew and spotters remain within the drop radius.
3. 3Substitution — Substitute oxy-cutting of lead-painted steel with mechanical shearing or cold-cut diamond wire sawing to eliminate lead fume generation at source.
4. 4Substitution — Replace dry concrete cutting with wet-cut diamond blade saws and hydraulic crunchers to suppress respirable crystalline silica below the 0.05 mg/m³ workplace exposure standard.
5. 5Engineering — Implement the engineered demolition sequence stamped by a chartered structural engineer (RPEQ or equivalent), with temporary propping and load-path verification at each hold-point before progression.
6. 6Engineering — Install perimeter scaffold with debris netting, catch decks beneath the work zone, and hard barriers protecting live traffic lanes in accordance with AS/NZS 1576 and AS 4687.
7. 7Administrative — Conduct daily pre-start SWMS sign-on, exclusion zone briefing, lift study review, and confirm road/rail possession authority is in force before any cutting commences.
8. 8Administrative — Operate under an approved Traffic Management Plan and Rail Protection Officer (RPO) supervision with positive communication protocols and emergency stop authority for all rail-adjacent work.
9. 9PPE — Mandatory hard hat to AS/NZS 1801, P2 respirators (or PAPR for lead/silica tasks above action level) to AS/NZS 1716, hi-vis to AS/NZS 4602.1, and cut-resistant gloves.
10. 10PPE — Twin-lanyard fall arrest harness to AS/NZS 1891.1 anchored to engineered anchor points for all deck-edge work, with rescue plan and trauma straps available on site.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

On a regional overpass replacement project, the demolition supervisor opens the morning pre-start brief by tabling the Bridge Demolition SWMS alongside the engineered sequence drawings and the approved Traffic Management Plan. The crew is about to sever and lift Beam 3 of 6 during a four-hour highway possession. Walking through the SWMS hazard register, the supervisor confirms with the dogman that the lift study weight matches the as-built beam plus residual deck, and that the tandem crane configuration is within 75 percent of rated capacity per AS 2550.1. A worker raises that the wet-cut saw water supply is intermittent — the supervisor pauses sign-on, references the silica control in the SWMS, and arranges a second IBC of suppression water before allowing work to proceed. All workers sign the SWMS register, including two new traffic controllers who are walked through the exclusion zone diagram and the emergency stop radio protocol with the Rail Protection Officer. Mid-task, a structural engineer's hold-point inspection identifies unexpected reinforcement continuity; the supervisor stops work, annotates the SWMS as a field amendment, briefs the crew on the revised cut location, and re-signs the document before the lift proceeds. The amended SWMS is retained in the project records for the statutory minimum period.

Related legislation

• WHS Act 2011 (model)
• WHS Regulation 2025
• Managing the Risk of Falls at Workplaces CoP

Frequently asked questions