Construction methods · Cable-supported and arch bridges

Arch erection by cantilever with temporary stays

Each half of an arch is built outward from the springing as a cantilever, held by temporary stay cables running over temporary towers to anchors behind the abutments, until the halves meet at the crown. Concrete arches use form travellers; steel arches lift segments with deck or floating cranes. The method for arches over gorges and rivers where the arch cannot be supported from below.

How bridges get built · Cable-supported and arch bridges · Arch erection by cantilever with temporary stays

Also called: cantilever arch erection, stayed cantilever arch, tie-back arch erection

Arch erection by cantilever with temporary stays — concept diagram — Concept diagram (TheBridgeEng)

How it is done

Build the abutments and springings; erect temporary towers on the abutments or piers and the anchorages behind them.
Advance the arch halves segment by segment; install a stay pair to each new segment and adjust the forces to keep the arch on its theoretical line.
Close at the crown with a closure segment or a jacked key; release the stays in a controlled sequence; build the spandrel columns and deck.

Where it fits

Concrete arches of 150-450 m and steel arches of 200-550 m over deep valleys and rivers; sites where a cable crane or float-in is not possible.

Where it does not

Spans small enough for falsework or a whole-lift; sites without room for the tie-back anchorages.

Plant, pace and money

PlantForm travellers or segment lifting cranes, temporary towers, stay cables and jacks, anchorages, survey.

ProductivityA segment pair per week; a 300 m arch in a year.

CostArch USD 3,000-6,000 per m2 of deck for the arch and temporary works.

Risks and controls

What goes wrong

Stay force errors distorting the arch, tower instability, crown misfit, wind on the cantilevers.

Quality assurance

Construction control with stage analysis, daily survey, stay force measurement, closure at the planned temperature.

Examples

Krk (390 m, 1980), Wanxian (420 m, concrete), Chaotianmen (552 m, steel), Almonte (384 m), Hoover Dam bypass (323 m).

In the bridge game

What Bridge Master applies when you pick it

Deck types: Concrete arch, Steel arch, Steel truss, Network tied arch. Spans 100-400 m, up to 450 m.

+30: Gorge arch: cantilever with stays.
-10: Long stayed cantilevers in wind need extra ties.

Try it in the game →