Architect: BBLUR architecture and CZWG architects
Structural engineer: Peter Brett Associates
Steelwork contractor: Caunton Engineering Ltd
Main contractor: Morgan Sindall
Client: Slough Borough CouncilThe three-level Curve building is 89.7m long, 15.5m high and has a width which is 34m at its maximum and 16.5m at its narrowest. With an overall floor space of 4,500m² the centre includes a library, café, office space and a 280-seat performance space.
The building’s form, a curved ‘tube,’ features fully-glazed entry façades, and opens onto two new public squares, created at each end of the building.
Constructing a building with this kind of complex shape brings with it a whole host of geometry and setting out challenges. The use of a BIM model, shared between the entire project team, made the design process less onerous.
The steel structure has falls in three directions, bull-nosed perimeters on two edges and cantilever projections on the other two faces. The 3D modelling and early engagement with the cladding contractor made steel the standout solution for this element of the building.
The low weight of the construction compared to a reinforced concrete frame provided significant savings in the deep concrete foundations, whilst reducing material movements off site and speeding up the construction programme.
The geometry of the façade presented particular design challenges.
Detailed three-dimensional modelling allowed efficiencies to be gained in specifying a constant bend radius for the façade members and limiting the supporting tubular transfer beam to three discreet bend radii.
This 45m curved CHS beam was then spliced using carefully detailed non-visible connections. Curved edges to the internal atrium required cantilever decking sections to arrive at site with the bend radii pre-cut.
Staircases both front and back-of-house were formed offsite in steel and installed quickly and prop-free to open up the site to the follow-on trades.
“Our expertise in BIM and 3D modelling using Tekla software has been a great benefit on this project, enabling us to integrate the original architect’s model with our own,” says Caunton Engineering Contracts Manager, Phil Ratcliffe.
Peter Brett Associates Project Engineer, Mark Way adds: “BIM was the best solution as it allowed everyone to see the same model and this made it possible to detect any possible problems well in advance.
Referring to why structural steelwork was chosen as the project’s framing material he adds: “Using steelwork made it much easier to design and form such a challenging shape.”
The steel composite frame was largely fabricated offsite and erected with minimal propping or insitu alterations.
The offsite nature of the fabrication process that included coating application increased the quality of finished steelwork coating system and meant the application process was not sensitive to weather conditions on-site.
The composite steel frame allowed floor depths to be kept within a stringent floor zone, while allowing for the services distribution. The main plant spaces were restricted to a stacked two-storey housing above the main vehicular access road onto the site. The span over the road was achieved with a two-level Vierendeel truss, clad with removable louvred cladding, to allow the plant installation and its future repair/replacement.
The installation of the Vierendeel truss, spanning over the main site access road, was done quickly with minimal closure of the thoroughfare.
The judges say in summary, the Curve provides popular and accessible community facilities. Its striking curved form arose from its proximity to a church and probably could only have been achieved by an integrated team using coordinated BIM design, analysis, fabrication and erection.
Elegant and effective steelwork meets unusual demands.
Photo: ©David Butler
Tagged 3D modelling, BIM, Caunton Engineering, cladding, commendation, Composite Construction, curved steel, Fabrication, Library, Morgan Sindall, Offices, offsite coating, offsite fabrication, Peter Brett Associates, Slough, Staircase, Tekla, theatre, Vierendeel truss