Featuring an architecturally detailed exposed frame, the commercial 21 Moorfields development in London had steel at its heart. With a project of this magnitude requiring high attention to detail and effective coordination, Trimble’s BIM software was an essential part of its delivery.
Located directly above London’s Moorgate Station, the new 21 Moorfields is an exciting 17-storey commercial development, offering 560,000 sq ft of office space. Reflecting the common themes of existing railway architecture, exposed steelwork was a key component of the architectural brief, featuring major trusses and structural arches.
Working with Sir Robert McAlpine for developers Landsec, William Hare (the global leader in engineered steel solutions) was appointed to deliver the steel detailing, fabrication, erection, temporary works and connection design – a mammoth undertaking.
Daniel Fenn, Engineering Manager at William Hare said:
As one of the largest steelwork contractors in Europe with a long history of delivering across a range of sectors, 3D modelling and the BIM discipline has been a key part of our business offering. For example, we’ve been customers of Trimble for around 20 years now, utilising its range of constructible modelling software and cloud-based collaboration platforms. On projects like 21 Moorfields, the importance of BIM goes far beyond just clash detection – it becomes a central collaboration tool.
A large amount of complex temporary works were required to enable the over-station build of 21 Moorfields and facilitate the construction of eight major trusses and six structural arches. Given its location directly above the busy Moorgate Station, with the new building essentially built on pile foundations and stilts, ensuring that the existing station roof wasn’t overloaded by the ongoing construction works was essential. As such, the new development had to be temporarily supported from underneath.
Speaking about the project’s temporary works, Daniel said:
Overall, there were around 1000 tonnes of temporary works required. Working with members of the Design Team, we modelled everything in 3D within Tekla Structures: the relevant existing station structure, the temporary steelwork and the new permanent steelwork. The ability to visualise it all within the one model certainly made life a lot easier for us.
When it comes to temporary works, the design is often heavily dependent on the permanent works design – and vice versa. For example, the team had to consider the extensive temporary works scheme alongside permanent steelwork connections and features, vehicular access zones and site obstructions.
Tekla helped to facilitate the effective coordination between it all, enabling us to consider and visualise the temporary alongside the permanent and create the optimum temporary works design. This included making use of Tekla Structural Designer and its links to the modelling software to quickly assess the evolving temporary works schemes as they were refined.
Moving away from the temporary works, the permanent structural steelwork presented just as much of a challenge, with the 21 Moorfields project being highly architecturally sensitive. Using Tekla Structures, the William Hare team was able to quickly detail and portray specific steel elements and connections, before then using this visual model to host workshops with the architect to discuss and refine.
Using Tekla, we were really able to visualise and see the proposed design – vital on an architectural project like this, where the steelwork forms such an important part of the overall building’s appearance. This worked on both a micro and macro scale: being able to zoom out for an overview of the model and view the context, but then also zoom into the smallest and most intricate detail.
“21 Moorfields had some incredibly complex geometry and steel connections. Without Tekla Structures and its constructible modelling capabilities, it really would have been difficult to visualise and get your head around it."
Coordination was another area where Tekla Structures helped to add significant value. Coordination with the other trades and project partners was a huge part of the job, with many complex interfaces, bearings and external cladding systems (to name just a few) to consider. With Trimble’s emphasis on Open BIM, we were able to encourage the use of 3D models, using other parties’ data within our own model, which really sped up the process.
Moving on to fabrication, here the data from the Tekla model helped to drive the fabrication and production process, informing the regular cutting, drilling and profiling.
As a company William Hare have also been finding ways to push this digital data integration even further, as Daniel explained:
We’re fortunate to have access to smart Zeman robotic machinery at our Scarborough facility. With this, we’re able to get pieces of fabricated steel that have had no physical human input following the detailing stage, relying solely on the data transfer from model to machine. However, as with all automation, the emphasis is on balance – while we use smart robotic machinery for the more standardised elements, we use our skilled and experienced fabricators for the more complex aspects.
Tekla-derived data is also used during the Total Station surveying of assemblies during and post-production. Used as a means of quality assurance and control, we’re able to survey the completed assembly and compare it with the model data – a far more efficient process than having someone with a tape measure manually checking the dimensions.
In addition to Tekla Structures, William Hare is a major advocate of Trimble Connect, with the cloud-based collaboration tool helping to facilitate the communication levels needed on large-scale projects, such as 21 Moorfields.
We use Trimble Connect a lot as a business – both internally and externally. We’re constantly developing how we use it and enhancing our workflow. In its core form, Trimble Connect is an excellent communication tool, providing access to the model and its project data for everyone, even those who aren’t experts at using specialist BIM software.
But we also use it as a problem resolution tool, from creating to-do lists and task delegation to task management, change management and query resolution.
On 21 Moorfields, as well as creating a line of communication between us, the client and other external parties, Trimble Connect was heavily used by our site team. In fact, it’s perhaps one of the projects where our site team has got the most engaged and involved with BIM, all thanks to Trimble Connect. Our site team found it really useful, especially given the complex install conditions and site constraints.
They were able to remotely view our own central model and other parties’ models too, seeing how they interact and comparing the model view with the real on-site context. It really helped from a problem-solving perspective, providing our site team with direct access to the model data and information.
21 Moorfields is expected to be completed in Autumn 2022.