The complexities of below ground construction, particularly in relation to the limitations on access, mechanical handling capabilities and space are often challenging. Cordek have a depth of experience accrued through previously undertaken tunnel related projects, providing bespoke formwork solutions for applications including: Intersections and cross passageways, Soft Eyes for Shaft Wall Construction, Transitions for Escalators, Ventilation Shafts, Pedestrian Walkways and Service Tunnels.
Each former is designed to meet the specific requirements of the project including the size, shape, finish and number of re-uses. Using this information, our designers will select the most appropriate material for each former and create a 3D CAD model for approval, which would then be used for CNC machining of the finished formwork solution.
*Please refer to National Structural Concrete Specification (NSCS) Edition 4 guidance available below.
Used for the construction of cast in-situ reinforced concrete tunnel structures with either complex or non-standard geometries, profiles and sizes.
When developing a tunnel former design, the following factors should be considered in addition to reviewing any CAD drawings, 3D models, specifications etc that are available:
Once the project requirements have been confirmed, a conceptual design can be completed along with provision of a quotation confirming proposed material type, features, quantities, manufacturing lead time and costs.
Typically, Cordek tunnel formers are manufactured from one of the following material types:
One of the factors determining the most appropriate material used to manufacture a tunnel former is the required concrete finish. Further information in relation to the classification of concrete finishes can be found within the National Structural Concrete Specification (NSCS) Edition 4 guidance, a copy of which can be downloaded from the Certification, Guidance and Approval section below.
Once approved, the agreed 3D CAD Model will be converted to CAM data, allowing accurate manufacture of the tunnel former via CNC hot wire cutting and / or 5-axis routing dependant on factors such as material type, complexity of shape / profile and required tolerances.
In some instances, due to the required dimensions of the formwork solution, it may comprise of a number of individual units that require assembly on site. This can prove advantageous in certain applications, such as those that have no mechanical handling resource or reduced restricted access.
In cases such as these, features such as tie bolt locations can be incorporated within the design to secure adjoining units together, aiding alignment during the installation process.