Special construction equipment · MSS

Movable Scaffolding Systems

A self-launching system for span-by-span construction of cast-in-place concrete superstructures, on continuous and simply supported bridges, without intermediate supports.

Discuss your project Arrangements

Movable scaffolding system spanning between two piers, its main girders carried at deck level on brackets seated on the pier shafts, with the deck being formed above. — Main girders carried below deck level on pier brackets, with the deck being formed above them.

Key specifications

Span range: 20–70 mWithout intermediate supports
Curvature radius: ≥ 250 mVariable radii of curvature
Deck depth: Constant or variableSix cross-section types
Arrangements: TwoUnderslung and overhead

Overview

What a movable scaffolding system does

A movable scaffolding system carries the formwork for one span of a cast-in-place concrete superstructure, supports it while the span is cast and cured, then releases and launches itself forward to the next span. The system is self-launching, so the sequence repeats without external lifting equipment.

Because the system spans between the permanent piers, no intermediate supports are needed at ground level. That is the property that makes it suitable where falsework from the ground is impractical.

Applications

Applications and construction method

The construction method is span-by-span casting of concrete superstructures in place, on both continuous and simply supported bridges. Each completed span carries the system forward to the next.

Bridge cross-sections accommodated

Capability

Span range, deck types and design considerations

Range and deck geometry

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Published span range and the deck geometry the system accommodates.
Span range	20–70 m
Intermediate supports	Not required
Bridge types	Continuous and simply supported
Cross-sections	Double-T, U-shape, single box, multi-cell box, box with struts, composite
Deck depth	Constant or variable
Horizontal curvature	Variable radii of 250 m or greater
Construction method	Span-by-span, cast in place

Adaptability and design considerations

Span-by-span without intermediate supports

Spans of 20–70 m are cast in place without supports between the permanent piers.
Variable horizontal curvature

The system is built to handle bridges with variable radii of curvature of 250 m or greater.
Different pier heights

The system is built to handle different pier heights along the same structure.
Diverse support configurations

It accommodates a range of bridge support configurations.
Constant or variable depth

Decks of constant or variable depth are accommodated across the six cross-section types.
Internal formwork rolling wagon

The system can be equipped with an internal formwork rolling wagon, also known as a collapsible hydraulic form-trolley, for formwork operations inside the box.

Configuration

Underslung and overhead arrangements

The system is supplied in two arrangements. Both perform the same function, and the choice between them follows the configuration of the bridge and the constraints of the construction site.

The two differ in where the main structure sits relative to the deck. The table below describes what is visible in the photographs beneath it.

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The position of the main structure relative to the deck, as shown in the photographs below.
Underslung	Main girders positioned at or below deck level, carried on brackets bearing on the piers.
Overhead	Main truss positioned above deck level, with the formwork suspended beneath it.

Underslung movable scaffolding system at a pier, its main truss girders carried at deck level on legs and brackets seated on the pier, with the formwork carried by the girders. — Underslung arrangement: the main girders are carried below deck level on brackets at the pier, and the formwork is carried by the girders.

Overhead movable scaffolding system at a pier, with the main truss carried above deck level and the casting form and working platforms suspended beneath it. — Overhead arrangement: the main truss is carried above deck level, with the casting form suspended beneath it.

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

Gallery