Cobute precast shutters for beams consists of two concrete L-shaped elements, reasonably light (20-37kg per linear meter), with additional steel fixed during the manufacturing process to avoid mishaps on site; this contributes to dramatically reduce carpentry costs.
Laboratory tests conducted by the Department of Civil Engineering at the University of Cape Town (UCT) on behalf of Cobute in 2004 have shown that R.C. beams constructed using the Cobute precast system have a higher bending moment capacity (approximately 10%) and practically the same shear strength capacity, compared to conventionally cast beams.
It simply consists of lifting the two L shaped elements into place and tying them together, using either binding wire or a timber clamp. The images below illustrate installation methods for beams and beam-in-slabs. Since only minimal shuttering and reduced number of props are required (approximately 2m centers), installation is a fast process. A 6 m long beam can be installed, ready for casting, in 30 minutes by 6 construction workers.
WIDTH - The Cobute beams can cover any possible width. In fact, as the elements generally consist of 2 L members whose soffit goes from 90 to 175 mm, the Cobute precast permanent shutters cover the width from 180 to 350 mm, going through any intermediate size. For width greater than 350 mm, it's possible to introduce a 3rd member or a panel to meet the design requirements.
DEPTH - The height of the side panel goes from 50 mm to 600 mm max. In case of deeper beams, it's possible to either add extra shutter on side or Cobute can manufacture the beam’s soffit with the steel cast in the factory and the contractor on site will shutter the sides using shutter board.
WHAT SETS COBUTE'S BEAMS APART?
- The system reduces waste by favouring timber saving
- Efficient labour and time management
- Shuttering is minimised, no stripping required
- Carpentry costs are reduced
- Beams longer than 7m can be split along the length, staggering the joint
- Minimal steel fixing on site
- Off-steel shutter mold finish
- When integrated with stairs and decking, the project can be cast in one pour, minimizing risks of cold joints and crack
Click here for the typical section of the downstand beam