TheBridgeEng

Erection method — first screening

Construction method selector

Which erection method should you even be shortlisting? Set the span, length and site conditions — the tool scores FSM, MSS, ILM, PSM and FCM against span bands from industry references (VSL, BBR, ASBI) and site-driven rules, and explains every plus and minus. Planning-level screening; the final call also weighs cost, schedule, contractor equipment and local practice.

Economical span bands (m) — your span marked

Best fit for this site

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Main span60m

2060100

Total bridge length600m

10010502000

Repetition amortises MSS / PSM / ILM equipment.

Under the deck

Alignment · span rhythm

#	Method	Score	Verdict	Working for it	Working against it

Basis: span bands from industry practice — span-by-span (MSS cast-in-place / PSM precast with gantry) is generally economical at 25–60 m and much faster than cantilevering; incremental launching suits continuous multi-span PT decks on straight or constant-curvature alignment; cast-in-place balanced cantilever (FCM) typically carries 75–260 m where support from below is impossible. Scores mix span fit with site rules (falsework feasibility, equipment amortisation over the bridge length, geometry constraints). This is a first screen — final selection also depends on cost level, programme, contractor equipment and local practice, and more than one method is often viable.

Field notes — what to watch for

The scoring is a screen, not a verdict — two methods within a few points of each other are genuinely interchangeable and the tender will decide. Watch the constraint inputs more than the span: crossing water or traffic quietly eliminates methods that look cheapest on paper.

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