A key piece of infrastructure, digital visualisation and coordination was essential on the construction of the new Stockingfield Footbridge, designed to connect three communities and provide residents with easier access to greener spaces.
Located in the Maryhill area of Glasgow, the new Stockingfield Footbridge is a twin span cable stay structure designed to provide access across the Stockingfield Junction on the Forth & Clyde Canal. Designed by Jacobs, the new Stockingfield Bridge has been delivered by main contractor Balfour Beatty for client Scottish Canals. With funding from Sustrans and the Glasgow City Council Vacant Derelict Land Fund, the bridge and wider connectivity project has been borne from community engagement and is part of a long-term partnership between Glasgow City Council and Scottish Canals.
As well as reconnecting three communities, it will also provide the last linkage in the canal towpath. With the bridge having been a topic of discussion for many years, with numerous proposed designs put forwards in that time, it is hoped that the completed structure will help boost recreational activity and offer easier access to greener spaces for local residents.
In addition to the two curved bridge decks, the structure features a viewing platform (taking advantage of the site’s elevated view) underneath a focal 34-metre-high inclined tapered mast.
SH Structures was responsible for modelling, fabricating, supplying and assembling the mast, twin decks, access ramps and stairs/balustrade system that formed the completed bridge structure, using a combination of Trimble’s constructible modelling software and hardware to deliver the works.
Speaking about the project, Martin Selby, Senior CAD Technician at SH Structures said:
The Stockingfield Footbridge project was particularly special to us for many reasons. Not only was it a chance for us to work with Scottish Canals, with whom we’ve developed an excellent relationship, but bridges are always unique, especially those which have been carefully considered and designed to create a legacy for the communities who use them.
Complex projects inevitably present a wide range of challenges and bridges of this scale are no exception. Perhaps our main challenge on this particular job was to develop a design that would give the required connection across the canal junction; getting something to work structurally that would cope with the complex dynamics and site topography, whilst also fitting into the congested site. Maintaining the required clearance under the bridge and the required slope of the ramps, while simultaneously tying into the alignment of the towpaths was also a major headache at the initial stages.
All of this resulted in a complex geometry where most of the deck section soffits were twisted plates. Curving steel in one direction is a relatively simple process but curving it in two directions, like we had to do here, was definitely more of a challenge. Using the Surface Generation Macro tool within Tekla Structures, we were able to easily generate the initial model, containing all of the information needed to fabricate the components.
It’s these areas of complexity where the 3D visualisation offered within Tekla is so valuable, enabling us to offer our client a fully rendered model, containing all of the materials – a model that can then form a central part of discussions.
As well as the Tekla Structures 3D detailing software, SH Structures also utilised the Trimble SX10 – a scanning total station that combines surveying, imaging and high-speed 3D scanning in the one instrument – coupled with a TSC7 controller.
Martin explained more:
Thanks to the software integration, we were able to export the completed Tekla model as an IFC file and import this directly into the SX10. This gave the engineering and site team full access to the accurate model data and 3D coordinates at any given point on the bridge structure, all of which proved vital when it came to setting out on site. Not only were we able to check that the dimensions and geometry were correct as assembly progressed, we were also able to verify the movements of the deck profile and mast as the cables were being tensioned.
Due to the size and complexity of the bridge, there were various sub-assemblies constructed using temporary works on a designated part of site. With three bridge sections (all of which had to come together at one central point before being welded into place) and the foundations and bearing points already having been installed by the contractor, everything had to align perfectly. We were working to some extremely tight tolerances. Here, setting out using the SX10 and 3D model coordinates helped to ensure all went ahead smoothly on site.
Nor did SH Structures stop there, pushing the data flow between Trimble’s BIM software and its site hardware even further. Having imported the IFC file into the SX10 device and using the SX10 camera, the team were able to view a live overlay of the model in the context of the real-time site.
This capability proved extremely helpful, ideal for checking and verifying that everything was lining up and in the right position – it really provided us with additional peace of mind”, said Robert Binks, Project Manager at SH Structures. “Being able to flip between live images and the 3D model gave a nice, visual representation of what you were currently seeing on site compared to the final end-goal.
“It’s also possible to use this same method and approach in the fabrication shop as a means of quality assurance and quality control – something we definitely want to explore further.”
Of course, the benefits of BIM go beyond just clash detection, accuracy and visualisation, providing a means of collaboration and communication also – two things that are essential on any construction or infrastructure project.
Speaking on the theme, Robert said:
A lot of the initial detailing stage was completed during the coronavirus outbreak, with restrictions meaning that the drawing office team were working from home. Tekla Model Sharing proved vital in helping the team to adapt and adjust to this new working style, ensuring that jobs were able to continue uninterrupted.
With such a large team involved on the Stockingfield Footbridge project, having access to a collaboration platform such as Tekla Model Sharing enabled everyone to work on the same model at the same time, without tripping over each other. In fact, this was one of the first projects where we used Tekla Model Sharing to such an extent.
As well as Tekla Model Sharing, Trimble Connect was also used extensively as a means of collaboration with the contract team, design team and other subcontractors on the project. It’s easily accessible, via your normal web browser - a feature that was really important for us.
SH Structures’ work on the Stockingfield Footbridge project saw the steel fabricator win Infrastructure Project in the 2022 Tekla Awards, with the judges praising the project as a great example of how to execute a Trimble model to field. The construction phase of the £13.7m Stockingfield Footbridge is now completed, with the bridge on track to open in September 2022.