Perronoverkapping Nijmegen

Project Overview
At Nijmegen railway station, DURA VERMEER, commissioned by ProRail, is constructing the platform canopy for tracks 5/6 based on a design by Office Winhov from Amsterdam.
Commissioned by DURA VERMEER, HEKO Spanten Ede is responsible for constructing the timber structure on top of the steel substructure. For HEKO Spanten, Teken- en Adviesburo Gerard van Meerveld carried out the full engineering of the double-curved beams and the single-curved roof panels. In addition, the steel plates connecting to the main steel structure and all timber-to-timber connections were fully detailed. All modeling was delivered at LOD 400 level.

Feasibility Study and Preparation
The project started with a feasibility study on the manufacturability of the required components. This study demonstrated that production was possible using the existing machinery and subcontractors of HEKO Spanten.
Subsequently, Teken- en Adviesburo Gerard van Meerveld investigated how to structure the model in a way that would result in a simple and workable setup, allowing all production data to be extracted directly without complex translations to machine output. Once this approach proved workable, HEKO Spanten accepted the assignment.

Modeling Strategy and Construction Setup
The next step was the actual construction of the model and placement of the model objects. The work began in a very basic way, by creating a 3D reference line system in AutoCAD, onto which the double-curved beams were positioned.
The fit with the main steel structure was developed using an IFC model provided by the steel contractor.

Detailed Engineering and Connections
All detailing was developed further within the Tekla model, based on sketches from the structural detail calculations. This process involved considerable trial and error, as double-curved beams intersecting with each other have no flat contact surfaces.
To solve this challenge, Gerard van Meerveld created custom user components for all connections. These components incorporate background dummy members, which are used to generate saw cuts and recesses at the ends of the spiral-shaped beams.
Due to the many aesthetic requirements from both client and architect, the details were adjusted multiple times. Thanks to the use of user components, these changes could be implemented efficiently throughout the entire model.

Review, Coordination and Mock-Up
The formal review by the client and architect is carried out using “flat” 2D drawings, supported by IFC models compiled by DURA VERMEER into a coordination model.
For visual assessment, a full-scale mock-up was built at the HEKO Spanten factory. This mock-up has since been reviewed and approved by both the client and the architect.

Collaboration and Communication
Internal communication within the HEKO team was handled entirely via Trimble Connect. This proved to be the fastest and most straightforward way to collaborate using a current model, accessible directly from Tekla with a single click.

From Model to Production
By using Tekla in combination with Trimble Connect, this highly complex model could be successfully translated into production. The extensive machine integration possibilities at HEKO Spanten ensured that the production workflow remained manageable. While the process requires thorough preparation, the final translation to production is relatively straightforward using Tekla’s multi-export module.
Working with multiple materials presented no obstacles, thanks to Tekla’s wide range of drawing configuration and export options.

Sustainability and Material Optimization
Significant sustainability improvements were achieved compared to the initial design and original requirements. Early designs included longer beams, which would have resulted in excessive timber waste, as double curvature would have required extensive milling from solid material.
The feasibility study conducted by HEKO Spanten showed that by using beams spanning from intersection to intersection within the arches (following the Zollinger principle), nearly identical beam lengths and geometries could be achieved. Additionally, these beams already obtain double curvature in their raw form by adjusting the gluing mold.
The laminated double-curved beams are produced by building up the beam height using multiple glued lamellae, each slightly rotated in height relative to the others. This process creates inherent double curvature in the raw element, significantly reducing material waste.

Conclusion
Overall, this project presented a major challenge due to its complex geometry and high aesthetic requirements. With the combined use of Tekla and Trimble Connect, these challenges were successfully addressed, resulting in a solution that satisfies both the client and production constraints.

Project Scale and Material Quantities
Due to the canopy length of nearly 240 meters, the sheer number of components posed an additional challenge. Below is an overview of the material quantities involved:

1,616 laminated beams
3,820 m² of surface area to be coated
136 m³ gross timber volume
126 m³ net timber volume
6,800 m² roof panels
9,200 screws for the laminated timber structure
7,700 M16 bolts for connection to the steel structure
29,150 Ø10 steel dowels for internal connections and steel interfaces
Approximately 30,000 screws for the roof panels