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PRESTRESSED SOLID COMPOSITE PLANKS - Construction Specifications

  • Propping: Where the floor is designed on a propped basis, props should be provided as follows:

Precast elements to be laid on pre-erected head-trees at right angles to span of units and left propped in position for seven days after topping is placed or until the characteristic strength of the topping has been achieved.

The props are intended to carry the temporary load during the construction sequence and their lateral spacing will depend upon construction dead weight and propping height.

The propping operation will eliminate any differential cambers between adjacent units.

  • Preparation of surface prior to concreting:

Before pouring the insitu topping the top surface of the precast element should be cleaned to remove any deleterious material, and moistened with clean water.

  • Generally transverse reinforcement in the topping should be F72 laid direct on top of the precast element and should project 450mm into adjacent bays.

Additional reinforcement may be required in areas of high concentrated loading or when a degree of moment continuity is required.

  • Curing of the topping should be carried out by covering with a suitable polythene or hessian or proprietary spray-on curing membrane.
  • Generally our solid composite construction is designed on a simply supported basis and construction joints in the topping should be located over supports in a lateral direction and over the middle of a precast element in the longitudinal direction. When large areas are involved the topping should be laid in a "chequer board" fashion.
  • Where precast elements are to be stacked temporarily on site they should be supported in a similar fashion to the way in which they are transported.

Stacking battens should be provided between each unit and placed vertically in line not more than 600mm from each end of the unit. Shorter panels must not be stacked on larger panels.

Design Data

General Description

 

The following pages of technical data are intended for the use of the designer in preparing detailed solutions for most span and loading conditions.

Information allows for the use of both 80mm and 160mm precast elements with various depths of structural topping.

The designs include precast elements capable of giving fire periods of either one or two hours.

Notes

  • The spans (metres) indicated in the tables allow for the characteristic imposed load shown at the top of the table plus the self weight of the floor plus a further 0.5kN/m2 for finishes.
  • The tables are based upon composite design using a structural topping with a characteristic strength of 32.0N/mm2 at 28 days.

Design data where structural toppings of alternative characteristic strengths are to be used can be provided on request.

  • All design is in accordance with AS 3600.
  • The maximum handling length of the 75mm thick precast element is 7.5m and 10.0m for the 100mm precast element.
  • Care must be taken on site to ensure that stresses arising during construction from transporting and stacking of building materials on the finished composite deck, do not exceed those calculated for the uniform distributed loads quoted.
  • All section properties shown are for a 2390mm wide precast element.
  • Unpropped construction should be considered where the span is less than 3.75m for the 75mm thick precast element or 5.0m for 100mm thick precast element or where the propping height is excessive.
  • All load/span tables are based upon simply supported spans. Where continuous designs are possible. longer spans may be achieved based upon normal design methods.
  • Topping thicknesses shown are minimum depths and account must be taken of the pre-camber of the prestressed element.
Prestressed Solid Composite Plants

Solid Slabs 2400 Wide UNO

75mm Topping UNO
1.5 Hr Fire Rating UNO

? - 1190mm Wide & - 1 Hr Fire Rating or 1.5 Hr and continuous in final situation
# - Construction Live Load Capacity less than 2.0 kPa Rqd
^ - Transfer Stresses require 25 Mpa at Transfer or extra top Reinf
* - Needs extra Rein (Flex and Shear)

  Load Span Chart
Span (m) 2 kPa 3 kPa 5 kPa 7.5 kPa 10 kPa
3 80S/8 80S/8 80S/8 80S/8 80S/8
4 100S/8 100S/8 100S/8 100S/8 100S/8
5 120S/8 120S/8 120S/8 120S/8 120S/8
6 150S/10 150S/10 150S/10 150S/10 150S/10
7 180S/10 & 180S/10 & 180S/10 & 180S/12 & 180S/10 &
8 200S/6 $& 200S/6 $& 200S/6 $& 200S/8 $& 200S/8 $&
9 200S/8 $& 200S/8 $& 200S/8 $& 200S/8 $& 200S/10 $&

Section Properties

Section Depth Width Effective Topping Thickness for Fire Rating Cross Section Area Ixx Dist Btm to Centroid Self Wt. Without Topping
  mm mm mm mm2 10^6 mm4 mm kPa
SOL80 80 2400 80 192000 102.4 40 2
SOL100 100 2400 100 240000 200 50 2.5
SOL120 120 2400 120 288000 345.6 60 3
SOL140 140 2400 140 336000 548.8 70 3.5
SOL150 150 2400 150 360000 675 75 3.75
SOL160 160 2400 160 384000 819.2 80 4

Disclaimer: Information on this site should only be used for preliminary designs. For the detailed information, please Contact Quickcell Technology directly