Information for the Superintendent and Foreman

Slipform Notes B

  1. A stair or ladder system or something similar should be provided by the Owner or general contractor so that the scaffolding can be reached at any height.
  2. Adequate lighting for all workplaces must be installed by the Owner or general contractor. A power supply connection of 380/220 volts, 50 cycles, 25 amps. with central conductor, must be made available for the slipform contractor in the vicinity of the site. Depending on the size of structure, power consumption during raising of the system ranges from 3 to 8 kW.
  3. The tower crane must be located in such a way that our entire equipment and shuttering can be unloaded, loaded, prepared, assembled and, if possible, dismantled within its working range. In order to ensure progress of work on large structures, it may be necessary to use an additional crane.
  4. In most cases, a marking-off base is required for preparation of the slipform system (this does not apply to bridge piers, tapering-circular structures, etc.).
  5. Applications for Sunday work during the slipforming period must be submitted — together with reasons — to the competent authorities.
  6. The slipform contractor must be provided with own lockable daytime quarters and a magazine, storage space, crane and band or circular saw. The site must be accessible to 20-ton lorries.
  7. Placing and removal of the platform boards must be carried out in accordance with the relevant accident prevention rules - in special cases, a statical check may be required. The platform boards must be provided by the Owner or general contractor.
  8. Boxouts equaling the wall thickness minus 1.5 cm should be installed by the Owner or general contractor. A steel reinforcement must be attached above the boxout.
  9. Insofar as jacking rods pass through openings of any kind, these rods must be carefully braced by the Owner or general contractor at intervals of not less than 50 cm.
  10. Safeguarding of the concrete cover for the reinforcements is best effected by guides fastened to the shuttering. The vertical leg of the guide - about 25 cm long - is bent over the top edge and then fixed in position.
  11. To obtain stability of the reinforcing cage, the joints of the reinforcements should be bound in such a way that the latter cannot become displaced. For the same reason, the intersections of the vertical and horizontal reinforcements must be reliably bound.
  12. All bent-up projecting reinforcements must be made of Grade I reinforcing steel (tensile strength 48,348 - 71,100 psi).
  13. The concrete is placed in uniform layers with a maximum thickness of 25 cm over the entire structure.
  14. Vibration should be confined to the freshly placed concrete, i.e. to a maximum depth of 25 cm, so that the previous layers are not disturbed.
  15. The first concrete fill should be placed in uniform layers of not more than 25 cm up to a height of 100 cm within 5 to 6 hours.
  16. The concrete emerging from the shuttering is normally troweled from the hanging platform by the personnel of the Owner or general contractor; if necessary, e. g. when ex-posed to cold, rain or solar radiation, this concrete must be protected by tarpaulins or some other means.
  17. The Owner or general contractor bears responsibility for the consistency, granulometric composition, quality, cement content and for adherence to all of these.
  18. The site facilities selected must guarantee a sliding speed of at least 15 cm per hour.
  19. The working hours of the slipform specialists will be counted as stand-by hours in the event of delays due to breakdown of the construction machinery and equipment or similar causes.
  20. Calculation of the slipped surface is based on the German Contract Procedure in the Building Industry; it should be noted, however, that - in contrast to the Contract Procedure - all openings shall be measured overall.
  21. Objections, if any, as to the dimensional accuracy of the structure must be submitted to 1GA in writing within a fortnight after termination of the slipform work.