Commercial

Auto Parts Pavilion 24 × 72 m in Atyrau

A two-storey retail pavilion 24.0 × 72.0 metres, 7.5 metres to the eaves. Its 3,456 m² of retail space stands on a frame that contains not a single hot-rolled member: columns, trusses, floor beams, purlins and bracing are all built up from cold-formed galvanised steel sections.

Atyrau3,456 m²2017

Project at a glance

Dimensions on grid: 24.0 × 72.0 m
Eaves height: 7.5 m
Ridge level: 9.6 m
Truss span: 12 m
Frame spacing: 4.0 m
Frame weight: 75.9 tonnes

Working design: SP-0365-KM, ProfilStroyProekt LLC, Saint Petersburg, 2016–2017

Structural solution

The frame is formed by columns, trusses, purlins and bracing. The first-floor slab is carried by transfer beams and joists supported on additional columns. Spatial rigidity comes from rigid connections between all members.

Every member is a cold-formed section

Columns, trusses, floor beams, purlins and bracing are made from cold-formed steel sections 100, 150, 200, 250 and 280 mm deep, in S245 steel to GOST 27772-88. For a two-storey building of 3,456 m² that is unusual: columns and floor transfer beams are more often hot-rolled. Here the load-bearing members are built up from paired sections — the central K-2 column, for example, is an assembly of six: two C250-2.0, two C250-1.5 and two C150-2.0.

The floor at level +3.8 m

The floor joists are paired C250 sections 12.1 metres long, 136 of them across the building. The transfer beams combine C280 and P284 sections into a single assembly. Profiled decking is laid over the beams and fixed in every rib, with a 50 mm screed on top. The design load on the floor is 5.66 kPa, of which 300 kg/m² is the retail live load.

A first floor of two 12-metre spans

On the ground floor the columns stand on five grid lines at 6 metres across the building. The intermediate K-3 columns stop at floor level and go no higher — above it only the outer rows and the central row continue. The upper retail hall is therefore covered by two 12-metre spans with no posts inside either of them.

Trusses spanning 12 metres

The roof is carried by 34 trusses — two per frame on seventeen frames, bearing onto the central grid line. The chords are C200-2.0 sections 12.1 metres long, the web is C100, and the joints use 4 mm plate gussets. Each truss weighs about 420 kilograms. The eaves are at 7.5 metres, the ridge at 9.56. Roof purlins are 200 mm Z-sections.

Assembled with screws and bolts

Frame members are joined with Ø6.3 × 25 self-drilling screws and bolts to GOST 7798-70; the column bases are fixed to the foundations with 12 × 120, 12 × 150 and 16 × 150 mm wedge anchors. There are no welding stations on site: erection depends neither on a welder’s skill, nor on the weather, nor on a power supply.

Galvanising instead of paint

The sections are galvanised at the mill, so the design expressly forbids welding or flame-cutting them on site — any cut or weld burns the coating off. Where galvanising is damaged during erection it is made good with a paint system to SP 28.13330.2012. Black-steel connection details are painted with two coats of PF-115 enamel over GF-021 primer.

Analysis and loads

The structure was analysed in the SCAD computational package, with loads taken from SP 20.13330.2011. Characteristic wind pressure is 0.38 kPa, the design load on the roof frame 1.78 kPa and on the floor 5.66 kPa. Walls and roof are insulated with 100 mm sandwich panels. Total steelwork weight is 75.9 tonnes — about 22 kilograms per square metre of the two floors.