Segment Box Girder Formwork

Segment Box Girder Formwork is a specialized system used in the construction of segmental box girders, typically employed in bridges and viaducts. This formwork system is designed to facilitate the casting of individual precast or cast-in-place segments that are later assembled to form the complete box girder.

Key Features of Segment Box Girder Formwork

Customizability
Designed to match the specific dimensions and profiles of each segment, including straight, curved, or tapered shapes.

Precision Engineering
Ensures dimensional accuracy for seamless alignment of segments during assembly.

Modular Design
Enables efficient reuse for multiple segments, reducing overall construction time and costs.

Surface Quality
Provides smooth finishes on both internal and external surfaces, minimizing post-casting surface treatments.

Adaptability
Suitable for various construction methods, including balanced cantilever, span-by-span, or incremental launching.

Components of Segment Box Girder Formwork

External Formwork

Forms the exterior surfaces of the box girder segment, including side walls and soffit (bottom slab).

Internal Formwork

Shapes the hollow interior cavity of the box girder.

Often collapsible or modular to allow easy removal after concrete curing.

End Shutters

Provide closure at the ends of each segment for precise shaping and proper alignment during assembly.

Support Structure

Includes falsework, scaffolding, or gantry systems to support the formwork and fresh concrete loads.

Adjustable Joints

Accommodate minor variations in geometry, ensuring a tight fit and smooth alignment of segments.

Applications

Bridge Construction
Widely used in segmental construction for highway bridges, railway bridges, and urban viaducts.

Curved Alignments
Ideal for constructing bridges with curves or varying profiles.

Precast and Cast-In-Place Segments
Suitable for both factory-controlled precasting and on-site casting.

Construction Process

Formwork Setup

Assemble the external and internal formwork components on a pre-prepared platform or scaffolding system.

Reinforcement Placement

Place steel reinforcements inside the formwork according to the structural design.

Concrete Pouring

Pour and vibrate concrete to eliminate voids and ensure a dense, strong structure.

Curing

Allow the concrete to cure to the required strength while maintaining proper moisture and temperature conditions.

Formwork Removal

Dismantle the formwork carefully without damaging the hardened segment.

Segment Erection

Transport the segments to the construction site and assemble them using techniques like post-tensioning or gluing.

Advantages

Precision and Alignment

Ensures accurate alignment of segments during assembly for a seamless structure.

Time Efficiency

Modular design allows rapid casting and reduced construction time.

Cost-Effectiveness

Reusable components lower overall material and labor costs.

Flexibility

Can accommodate complex geometries and varying segment designs.

Structural Integrity

Produces robust and durable segments suitable for high load-bearing applications.

Construction Methods Using Segment Box Girder Formwork

Balanced Cantilever Method
Segments are cast in place or assembled symmetrically from piers to maintain balance.

Span-by-Span Method
Entire spans are assembled and then lifted into position.

Incremental Launching Method
Segments are cast and then pushed forward into their final position.