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Testing & Certification

General

The Ultrafloor system is compliant with the relevant provisions of AS 3600 (the concrete code), AS 3610 (the formwork code) and the Building Code of Australia (BCA).

Since November 1990, physical testing of the Ultrafloor range of products has been performed at the following organisations to verify and maximise the structural capacity and other characteristics which can be used in design:

  • University of Sydney
  • University of Newcastle
  • University of New South Wales
  • Melbourne University
  • CSIRO
  •  PKA Acoustic Consulting

AS 3600 & BCA Compliance

Expert reports by independent consulting engineers have confirmed the compliance of the Ultrafloor system with the BCA and concrete code(s).

In September 1999, the consultants Connell Wagner of Neutral Bay NSW undertook a study of these matters.

The aim was to address any potential concerns that might exist in the construction industry regarding compliance of the Ultrafloor system with the requirements of AS 3600 and the BCA.

Their report returned the following key findings:

1. The strength of concrete used in Ultrafloor joists is adequate for achieving the design capacities presented in the manual.

2. Ultrafloor joists exhibit adequate flexural strength and ductility in their noncomposite/formwork state. They are also capable of developing their full theoretical flexural capacity in the composite state.

3. The wedge-profiled unsmooth upper portion of Ultrafloor joists produce adequate mechanical engagement and chemical bond to the topping slab to maintain full composite action from early age to long term.

4. High quality well-compacted concrete used in the joists ensures that shorter strand
transmission lengths than those specified in AS 3600 are achievable. As a result, adequate support can be provided to the joists with 60mm bearing length without any danger of debonding.

5. Ultrafloor joists have adequate shear strength to prevent any premature failure mechanisms due to flexure-shear or web-shear cracking.

   6. Flush-soffit post-tensioned band beams can adequately support Ultrafloor slabs owing to the mechanical interlock between the joists and the band. Clamping and wedging actions generate this interlock. Should restraints cause the prestress to be reduced below the tested levels, the clamping actions may be reduced.

7. For design of a composite joist (T-section) subjected to concentrated loads, adjacent Tsections (one on either side) can be used to share the actions induced by concentrated loading.

8. The Ultrafloor slab system can provide a diaphragm action superior to that of a 90mm conventional slab for receiving, transmitting and redistributing lateral loads originated from wind and earthquakes.

9. Under both short-term and long-term effects, Ultrafloor slabs exhibit similar (if not better) deflection performance than other commonly used slab systems. They perform similarly with respect to floor vibrations and crack control.

10. Ultrafloor joists have adequate concrete strength and cover for strands to satisfy the durability requirements of AS 3600 for all exposure classifications up to level B2.

11. All types of Ultrafloor slabs comply with the requirements for a 120-minute fire insulation period. They can also provide fire ratings of (at least) 120 minutes for structural adequacy.

12. Ultrafloor slabs have considerable ductility at midspan and sufficient rotational capacity over the support. This makes them suitable structural components of a robust design preventing any progressive collapse.

The Connell Wagner report made reference to documentation by other parties including the following:

1. Taylor Thomson Whitting Pty Ltd, Consulting Engineers (of St Leonards NSW), who in August 1995 and May 1998 issued appraisals of the Ultrafloor building system.

2. CSIRO Division of Building Construction and Engineering (at North Ryde NSW), who in August 1996 issued National Certificate of Registration of a Building Product No.95/0463. (This product registration system ceased in 1999).

3. Harold Roper and Associates (of Sydney), who in February 1994 consulted on durability design.

4. Worley Fraser Pty Ltd, Consulting Engineers (of Melbourne), who assessed the system with respect to robustness and progressive collapse. They relied on the British Code, BS 8110, to conclude that Ultrafloor elements are suitable components in robust design preventing progressive collapse. 

Band Beam Testing

In July 2000, the University of Sydney conducted structural testing of the band beam system and concluded as follows:

In both the reinforced and post-tensioned concrete band beam cases, the band beam behaved as if it were monolithic. There was no aspect of the behaviour to suggest that the Ultrafloor beams would separate from the band beam in an untoward manner.

Theoretical ultimate flexural capacities were achieved in every test. The band beam behaviour was ductile and deflections were small.

Cracking was well controlled and developed slowly at loading well beyond working levels.

The specimens were designed to ensure that realistic bending moments and shears would be applied at correct relative values and there was nothing in the tests to suggest that unsatisfactory flexural or shear behaviour would occur in practice.

ULTRAshell Testing

Between November 2000 and July 2001, the University of New South Wales conducted structural testing of the Ultrashell system to establish the presence of composite action between the precast, pre-tensioned concrete shells and the cast-in-situ concrete topping slab. The exercise was undertaken in collaboration with the consulting engineers, Taylor Thomson Whitting Pty Ltd (TTW).

In the series of nine tests conducted for flexural and flexural-shear strength, and over the full range of loading, no visible longitudinal slip occurred between the precast shell and cast-in-situ concrete slab. This validates the design assumption that full composite action is attained between the two elements.

In addition, there was close correlation between the theoretical capacities calculated by TTW and the experimental capacities determined by this testing.