A Memo from Jack Cowan
P.O. 21554,
Columbus, OH 43221-0554
Phone: (614-486-0707 Fax: (614) 486.0739
jack@jackcowan.com
http://www.jackcowan.com
To all users of the Conasco void drain/vent/chair/spacing device.*
Over the years, particularly since the advent of EPS void forms for rectangular box beams, placing tolerance concerns have emerged. The Prestressed Concrete Institute’s requirements are plus or minus 1/2” top, 3/8” sides, and +1/2”,-1/8” bottom. These critical placing tolerances are meant to assure proper top thickness but also sufficient strand cover in the bottom of the girder, in addition to side thickness requirements.
While the CONASCO void drain performs well as an inexpensive screed guide for the first stage pour, the proper positioning of the void form upon the void drain and an adequate screed level guide has been missing as indicated by a number of calls from box girder manufacturers. (The EPS void form presses down on the void drain top, and the drain penetrates the void form during initial fabrication, compromising critical tolerances).
Responding to these concerns, we developed the CONASCO void drain bearing plate or “SHOE” (part number C-VDS) to eliminate what is obviously a concern among producers, to adhere to the placing tolerances specified by PCI. This new product should prove to be a welcome addition in the ongoing quest to improve the quality and durability of precast and prestressed concrete box beams using rectangular or round void-forms.
A large (5” X 5”) bearing area, with cleats to grip EPS and to cradle round paper voids is provided. (See photo #1).Multiple holes minimize vibration uplift forces and air-voids. The SHOE friction fits to the Conasco void drain eliminating the need for mechanical attachment devises or adhesives. The knock out in the top of the void drain is exposed. A bright yellow color makes the SHOE easy to see when establishing the screed level of the bottom slab. Strapping slots are provided to secure the void-form to the bearing plate if desired. (See photo #2).
The C-VDS void drain/screed SHOE is available from stock. Please call me for packaging, pricing and other suggested applications.
Thank you.
* Protected by patents and trade marks. Other patents pending.