FP McCann's BIM Ingenuity Speeds Up Industrial Job | Accelerating The Design Process

Working with Tekla software, FP McCann was able to  accelerate the design process for bespoke precast units on a Daventry logistics hub, its first BIM Level 2 project.

A recent FP McCann industrial project in the East Midlands demonstrated the precast specialist’s ability to work flexibly within BIM software to create quick and innovative design solutions.

Phase III of the Daventry International Rail Freight Terminal (DIRFT 3) is a vast, 345-hectare construction project, where the developer is property  and logistics giant Prologis.

For one of the warehouses, FP McCann was required to design and construct a series of precast concrete dock leveller pits. These allow access for delivery vehicles which are at different heights to the loading dock or require a bridge across the gap between the dock and the vehicle floor. With a variety of transport using the warehouse, loading docks need to accommodate many different vehicle sizes. 

The precast concrete pits are formed from a combination of perimeter retaining walls and biscuit slabs, which support a dock leveller ramp that connects to the delivery vehicles. To accelerate the design of the precast units, FP McCann’s senior technician Colin Mackenzie came up with a novel approach using Trimble’s Tekla software.

“Tekla is a very robust program, which can be used to model anything, and using its custom component editor, it’s possible to make big efficiency savings in the design,” he explains.

The custom components editor is an intelligent tool that allows dependencies to be built between objects in a model, so that if the size of one component is changed, other dependent components will automatically be adjusted too. On a precast project with many bespoke units, but which all share common characteristics, the custom components editor can be used to speed up the design considerably.

“On DIRFT 3, there were, for example, 77 T-wall (front wall) sections required, of which 30 were bespoke,” explains Mackenzie. “Each one would have taken two hours to model individually. Instead, at the outset of the design process, using the components editor, I modelled the geometry of the precast units and defined possible parameters for the bespoke elements.

“Then, when the designers began work, they would be presented with a dialogue box – as you would find in any Windows-based program – which allowed them to define the bespoke requirements of each unit, such as different dimensions, fixing positions, and so on.

“Working this way, we were able to design each unit in just two minutes. The total modelling took less than a week.”

The largest precast units on the project were the giant ‘Prowall’ sections, which span between the pits, and measure up to 8m long and 4m high on average. Varying in thickness from 275mm to 335mm, they comprise two skins of concrete and an insulation layer. “Each section requires 100 Thermomass ties between the concrete and insulation layers, in specific spacings, which we were able to model quickly in Tekla,” says Mackenzie.

The T-wall units required a bespoke design for the reinforcement to allow  for a services channel to be threaded through (see image).

FP McCann also has an interface between Tekla and its rebar bending machines, which adds further efficiencies to the design and manufacturing process. “Tekla can supply the data to the industry standard PXML, which is fed into the machine and then the correctly-formed rebar comes out of the other end,” says Mackenzie.

“We are also able to export from Tekla into IFC models, which we did on the DIRFT 3 project, which allowed the contractor, engineer and architect to coordinate construction activities on site,” he adds.

“We are now certified to work at BIM Level 2, through BSI, and this was our first Level 2 project.”

The next step in FP McCann’s BIM transformation is coordination with logistics. “Software firm StruSoft has supplied us with their Impact system, which links with our modelling data, and allows our planners to assign units to casting beds in the factory and then link up with deliveries to site,” Mackenzie explains.

FP McCann’s dock leveller pit system at DIRFT 3 was supplied from its production facility in Byley, Cheshire and installed by its specialist on-site team. The project completed last year.