|
Current Cost Data April 2010
Cost information for steel in composite construction for members of the Australian Institute of Quantity Surveyors AIQS
Costs compiled late 09 and updated for steel price increase April 2010
Contributing Fabricators and Steel Contractors
Sebastian Engineering NSW contact Mark Sgaravizzi
Monks Harper Vic, Page Steel Vic contact David Hentschke
Page Steel Vic contact Chris Piacentini
BlueScope Buildings NSW contact Brent Poll
Steel Fabrications of Australia ( Brisbane Steel Fabrication) contact Lindsay Allen
Advanced Steel Fabrications SA contact Leno Zenardo
Bianco Structural Steel SA contact Kon Fountoglou
The members of the AIQS have requested the ASI to provide updates of market structural steel costs for low to medium rise commercial composite construction.
Based on modeling through an AusIndustry ICIP Grant, the ASI has taken a Cox Richardson design and an Arup engineered model and averaged the rates for steel fabrication. This is intended to give the AIQS community a guide on fabricated, detailed and erected steel rates for buildings of a similar nature. Further queries may be taken up with the steel fabricators directly.
STRUCTURAL BEAMS, COLUMNS and PLATE
| Section Size |
Total tonnes |
Rate per tonne |
| 100X100X6EA |
1.39 |
$11,807 |
| 200UC47 |
0.91 |
$4,969 |
| 250UB38 |
14.96 |
$3,355 |
| 250UC91 |
12.73 |
$3,355 |
| 310UB41 |
6.86 |
$4,580 |
| 310UC119 |
7.15 |
$3,355 |
| 310UC138 |
2.08 |
$3,355 |
| 310UC159 |
14.41 |
$3,355 |
| 350WC198 |
8.98 |
$3,948 |
| 360UB44.8 |
10.57 |
$4,580 |
| 360UB56.8 |
5.25 |
$4,580 |
| 410UB53.8 |
2.12 |
$4,580 |
| 460UB67.2 |
18.34 |
$3,281 |
| 460UB75 |
249.01 |
$3,281 |
| 508CHS6.5 |
4.14 |
$6,903 |
| 530UB83 |
21.40 |
$3,281 |
| 530UB93 |
3.97 |
$3,281 |
| 600CHS6.5 |
8.32 |
$6,903 |
| 610UB102 |
33.21 |
$3,281 |
| 610UB126 |
28.27 |
$3,281 |
| Plates etc (allowed 6% of total steel |
13.60 |
$5,200 |
AVERAGE STEEL FRAME COST PER SQM INCLUDING DECK 245 $/sdqmetre
The Building
· This generic design presents a structural steel frame solution for a new 4 storey office building, providing commercial Grade A space of approximate NLA of 8000m².
· The four office levels (namely Ground, First, Second and Third) and Roof are suspended, and each extend over approximately 2000m2.
· 200 m2 of centralised compactus area is provided on each of the office levels.
· A double height foyer is formed by the omission of any slab at First directly above.
· The internal area at Ground incorporates a 150m2 area of set downs within the slab for foyer finishes and a central wet areas; the remainder floors have 80m2 set downs areas located centrally between cores for the wet areas.
· A large plant enclosure of approximately 300m2 is designated at Roof.
· The building is air conditioned with a chilled beam system.
Structural Form
· All structural framing is provided using hot rolled steel (i.e UB, UC, CHS, RHS) – special fabricated structural members are not required. There are no specialised or complicated fabrication methods required for the frame.
· The foundation to the building has not been considered in this study; if a basement is not provided, a ground bearing slab, a foundation raft, or similar can be substituted at Ground, and the associated framing should be omitted from the material take off.
· The building’s 12.5 x 8.4 m grid offers an 8.4m span (longitudinal) primary beams arrangement, which in turn support secondary beams spanning 12.5m span (laterally) at 2.8m spacing.
· In order to counteract deflection of the steel beams under their ‘construction condition’ (i.e. prior to them developing composite action with the slab), the composite beams are precambered where required.
· Where possible the beams are designed to act compositely with a 120mm deep slab, which is cast on a continuously spanning re-entrant steel deck, by the provision of through-deck welded studs and mesh reinforcement.
· The direction of the steel deck troughs are parallel with the primary beams and as such, the dimensions between the stud centres are able to be closed or opened as appropriate to maximise the steel member size and to optimise the appropriate number of studs. The studs to the secondary beams are placed within the troughs to the decking which spans parallel to the beam.
· Floor to floor heights are typically 3.7m; all columns are founded at 3m below the Ground.
· The building is serviced by chilled beam cooling. Beams supporting Roof, Third, Second and First host an extensive arrangement with over 100 web penetrations per level to accommodate the ductwork’s reticulation within the ceiling’s service void within the depth of the floor beams. There are no requirements for web penetrations to Ground supporting beams.
· The web penetrations are rationalised into just 4 types, and their design have been iterated with close attention to the balance between final choice of beam section vs floor to floor heights vs the requirement for a non- stiffened web penetration.
· Close integration with the mechanical duct design results in just 2 beams per floor being provided with bottom flange notches.
· Cast in plates have been designed for the connection between the reinforced concrete cores and intersecting steel beams. Each floor has specific requirements for the plates’ positioning, with 15 to 20 plates per level being required. L bar reinforcement is provided between the core walls and the composite slab. A drilled ‘flexible’ fin plate is site welded to the cast in plate and the supported beam’s web is drilled match the fin plate.
· Cantilevering slab edges provide a column free façade on the lateral ends of the structure. This is possible by having the cantilever primary beam extend through the CHS supporting column. The portion of the column above and below the beam is welded to the beam, effectively being delivered as one assembly. The CHS columns bolt between these assembelies at every level on site.
· Beam to beam connections are provided by drilled ‘flexible’ fin plate welded to the supporting beam. The supported beam’s top flange is notched and it’s web is drilled match the fin plate.
· Beam to column connections are also provided by drilled ‘flexible’ fin plates welded to either the column’s flange or web. When connecting to the column web, the supported beam’s flanges are notched for fit.
· The remainder UC columns are only spliced once above level, at a suitable level so as to be useful within an appropriate mansafe system during erection. The section size of the column alters to a more economic section above the splice.
· A façade system’s secondary framing is not included within the Generic Design, however appropriate loading has been allowed for in the design for a façade to be vertically supported on each level’s perimeter edge beams.
· The Generic Design of the structure is to conform to AS 4100 and AS 2327.1.
· All steel is typically Grade Onesteel 300PLUS. The 508CHS columns are Grade 250.
· Through deck welded studs are 19mm diameter x 100mm (95mm after welding).
· All bolts to be M20 8.8/s.
· Slab to be 120mm overall, on a 1.0mm Bondek re-entant steel deck; normal weight 32Mpa concrete (2400kg/m3) with SL82 mesh.
· Note steel is unpainted in accordance with design.
|
