Construction methods · Finishing, articulation and maintenance

Parapets, barriers and edge details

The concrete or steel barrier along the deck edge that keeps vehicles on the bridge, tested to a containment level; plus the kerbs, drip grooves, cable troughs and noise screens that finish the edge. Slipformed concrete barriers finish a kilometre a day; steel parapets bolt to cast-in sockets.

How bridges get built · Finishing, articulation and maintenance · Parapets, barriers and edge details

Also called: bridge barriers, crash barriers, parapet construction, slipformed barriers

Parapets, barriers and edge details — concept diagram — Concept diagram (TheBridgeEng)

How it is done

Cast the deck edge with the barrier starter bars or sockets; slipform or cast the concrete barrier in one pass, or bolt the steel parapet to sockets set with a template.
Install drip grooves and drainage at the edge; fix cable troughs, lighting columns and noise screens to the barrier.
Add transitions to the approach barriers and the end terminals.

Where it fits

All bridges; containment level by road class.

Where it does not

Barrier bases without drainage (water sits against the deck edge); untested transitions.

Plant, pace and money

PlantSlipform paver or forms, small crane for steel parapets.

ProductivitySlipformed 300-1,000 m per day.

CostUSD 300-800 per metre depending on type.

Risks and controls

What goes wrong

Bar anchorage at the deck edge, cracking of slipformed barriers, transitions failing in impact.

Quality assurance

Crash test certificates for the system, anchorage inspection, transition details checked.

Examples

F-shape and single-slope concrete barriers on highways; steel parapets on urban and rail bridges.