What Is Form Traveler In Construction?
What Is Form Traveler In Construction?
A form traveller is a type of travelling formwork system used in bridge construction. It enables the repeated construction of structural elements and is typically used for free cantilever construction of post-tensioned box girder and cable-stayed concrete bridges.
Form travellers are supported by the part of the structure already built, and can be overhead or underslung
Form traveller is a system used for free cantilever construction of post-tensioned box girder and cable-stayed concrete bridges. It is lightweight, versatile, easy to assemble and operate, rolling forward on rails or rollers, and supports the weight of the construction elements including formwork, traveler, reinforcement and uncured concrete.
The form traveller system is designed to be highly stable and rigid so that it does not move significantly under the weight of the concrete as it is poured or during curing. It also has features such as being portable and cost effective.
The Standard form traveller is intended to be used for bridge construction and has a maximum segment length of 5 meters. The load capacities for concrete and formwork can range from 250 to 400 tonnes. The weight of the steel used in the form traveller depends on the specific cross-section of the bridge, typically ranging from 25 to 65 tonnes.
It is possible to modify the Standard form traveller to fit almost any cross-section and adjust it during use to accommodate changes in segment length, section height, web thickness, and deck width.
What Is Form Traveler Used For?
Form travellers are used for free cantilever construction of post-tensioned box girder and cable-stayed concrete bridges. They are lightweight, versatile, easy to assemble and operate, rolling forward on rails or rollers, and offer significant cost savings over traditional methods.
Form travellers are preferred for building spans over deep valleys, waterways, and roads where access from the ground is a challenge and the number of piers is limited.
The main advantage of form travellers over other construction methods is that they allow for longer and wider spans to be built with less material than traditional methods.
Form travellers come in two types: overhead form travelers which are suspended underneath the bridge structure already erected, and under-slung form travelers which are mounted on top of the structure already erected.
Is Form Traveler Used For Construction Of Superstructure?
Form travelers are commonly used for the construction of cantilever segmental bridges, as they provide a convenient and efficient means to build superstructures.
These form travelers give shape to the segment, support the weight of the newly cast concrete until it has gained enough strength to be post-tensioned to the previous cantilever segments, and transfer the segment weight to the already existing superstructure.
Form travelers can also be used in certain circumstances for other types of bridge structures (such as truss or arch bridges), depending on the specific design requirements.
Form Traveller Installation
Installation of form traveller involves assembling the equipment on the ground and lifting segments by crane to their starting points on a specific bridge pier.
Form travellers come in two main types: overhead and underslung, with both being designed for free cantilever construction of pre-stressed girder and cable–stayed concrete bridges.
Structural analysis is used to improve the performance and alignment of bridges, as well as ensure that the formwork does not move significantly under the weight of the concrete during pouring or curing.
Form Traveller Components
Form traveler components consist of a main frame, walking and anchoring device, bottom mould frame, side mould frame, inner mould frame, front lifting device and rear lifting device which are important for the smooth functioning of form travelers.
The main frame provides stability to the whole assembly while the walking and anchoring devices assist in its movement. The mould frames form an enclosure for supporting the form structure pieces and the lifting devices on both ends help in moving them between different levels.
