Special construction equipment · LG

Launching Gantries

A self-launching gantry for precast segmental bridge construction, supporting both balanced-cantilever and span-by-span erection, with an integrated gantry crane.

Discuss your project Arrangements

Launching gantry above a bridge pier lifting a precast concrete box segment, with a second segment already positioned beneath the gantry. — Precast box segment lifted by the gantry above the pier, with the preceding segment already in position.

Key specifications

Curvature radius: 75–100 mAs tight as, depending on span length
Launching: Self-launchingFully self-launching operation
Gantry crane: IntegratedSupplied as part of the gantry
Erection methods: TwoBalanced cantilever and span by span

Overview

What a launching gantry does

A launching gantry erects precast segmental bridge superstructures. It spans between the permanent piers, lifts each precast segment into position with its integrated gantry crane, holds the segments while the span is assembled, and then launches itself forward to the next span.

The gantry supports both principal precast segmental methods: balanced cantilever, where segments are placed alternately either side of a pier, and span-by-span erection, where a complete span is assembled between piers before it is stressed.

Applications

Applications and construction method

Precast segmental construction, on continuous and simply supported superstructures. Because the gantry is fully self-launching, each completed span becomes the support from which the next is erected.

Methods and span types supported

Capability

Alignment, span types and design considerations

Published capability

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Published capability of the launching gantry.
Horizontal curvature	Radii as tight as 75–100 m, depending on the span length
Launching	Fully self-launching
Lifting	Integrated gantry crane
Continuous bridges	Box-section spans
Simply supported bridges	U-section or box-section spans
Erection methods	Balanced cantilever and span by span
Arrangements supplied	Underslung and overhead

Design considerations

Tight curvature

Bridges with curvature radii as tight as 75–100 m are handled, the achievable radius depending on the span length.
Self-launching operation

The gantry launches itself forward from span to span, without external lifting equipment.
Integrated gantry crane

The lifting equipment is part of the gantry, so segment handling and placing are carried out by the machine itself.
Continuous and simply supported spans

Box-section spans are erected on continuous bridges, and U-section or box-section spans on simply supported bridges.

Configuration

Available arrangements

Launching gantries are supplied in underslung and overhead arrangements. The arrangement is selected on the configuration of the bridge and the constraints of the construction site.

The capabilities set out on this page apply to the equipment generally. Both arrangements are fully self-launching, and each is supplied with an integrated gantry crane.

Selecting the arrangement is project-specific and is settled by engineering assessment of the bridge configuration and the site constraints.

Gallery