Prestressed Slabs

General Information

Prestressed concrete is used in a wide range of building and civil structures where its improved concrete performance will allow for longer spans, reduced structural thickness and materials savings to be realised compared to reinforced concrete. Choosing to use Ducon Concrete Ltd. for your prestressed slabs offers you, the customer a number of advantages:

  • Prestressed Slabs Design Process – Submit your plans to Ducon Conrete Ltd and we will calculate, measure, specify and manufacture slabs to suit your project.
  • Construction Process – You benefit from a faster build time based on the speed of manufacture & selection of prestressed slabs.
  • Quality Controlled Products – Prestressed slabs are CE approved and manufactured in a controlled environment.
  • Units are supplied with pre-stressing strands complying with BS 5896: 1980.
  • Openings and notches can be incorporated into the slab design allowing for services etc. to pass from floor to floor.
  • All units achieve one hour standard fire resistance in accordance with TB 4.4, BS 8110, Part 2 – 1985. This may be increased to two hour fire resistance on request. Please consult our technical office for additional details.
  • Joints between units must be adequately grouted using 3:1 sand/cement mortar or 30 N/10 concrete, prior to the addition of any service loading or structural screed where appropriate.
  • Where slabs are to be temporarily supported during construction, this shall be done in accordance with the details on the relevant slab layout drawing, and within the provisions of section 6.9, BS8110, Part 1 – 1985.

Benefits of using prestressed slabs

  • Higher load capacity – long spans making it structurally efficient.
  • Provides high levels of inherent fire resistance
  • Provides excellent sound resistance
  • Quick installation ensures a reduction in building programme time.
  • Slabs can be grouted immediately after installation providing a stable floor suitable for working off.
  • Progress on site is not weather dependent.

Cross sections

HOLLOWCORE SECTION PROPERTIES

UNIT TYPE
mm2 150mm 200mm 250mm 300mm 400mm
Property 15R7 20E11 25E6 30E11 40E6
A mm2x103 124 151 167 212 223
Self-Weight Kg/m2 254 298 330 418 438

Hollowcore load span tables

  • Allowable spans refers to distances between support centres. These are maximum figures for each floor depth calculated with consideration of stresses induced from handling and transportation, in addition to flexural design. Further consideration of camber and deflection may also be required, consult our technical office for details.
  • Figures tabulated include an allowance for self-weight and structural screed where appropriate. No allowance is taken for floor finishing screeds, partitions, services, ceilings, etc.
  • Tables are not intended as a substitute for design. Please consult our Technical Office to discuss all design considerations.
Table 1 Allowable Spans (m) for Superimposed loadings kn/m2
CASE A UNIT ONLY
Unit Superimposed loading kn/m2 allowing for self-weight only
Depth 1.50 2.00 3.00 4.00 5.00 7.50 10.00
150 7.20 7.20 7.00 6.45 6.00 5.10 4.60
200 9.75 9.75 9.55 8.85 8.25 7.10 6.40
250 10.40 10.00 9.65 9.30 8.40 7.30 6.95
300 12.00 12.00 12.00 11.30 10.60 9.40 8.40
400 CONSULT TECHNICAL DEPARTMENT
Table 2 Allowable Spans (m) for Superimposed loadings kn/m2
CASE B Unit + 50 mm structural screed
Unit Superimposed loading kn/m2 allowing for self-weight + 50mm screed
Depth 1.50 2.00 3.00 4.00 5.00 7.50 10.00
150 7.20 7.20 7.05 6.60 6.30 5.65 5.20
200 9.75 9.75 9.65 8.90 8.45 7.65 7.00
250 10.40 10.40 10.00 10.00 8.50 7.70 7.40
300 12.00 12.00 12.00 11.95 11.75 10.75 8.70
400 CONSULT TECHNICAL DEPARTMENT
Table 3 Allowable Spans (m) for Superimposed loadings kn/m2
CASE C Unit + 75 mm structural screed
Unit Superimposed loading kn/m2 allowing for self-weight + 75mm screed
Depth 1.50 2.00 3.00 4.00 5.00 7.50 10.00
150 7.20 7.15 7.10 6.60 6.35 5.75 5.35
200 9.75 9.75 9.15 8.85 8.45 7.70 7.15
250 10.40 10.40 10.40 10.25 9.50 8.05 7.85
300 12.00 12.00 12.00 12.00 11.85 10.80 9.75
400 CONSULT TECHNICAL DEPARTMENT