Advantages of precast framing/cladding
Precast construction can be cost effective both on a first cost and on life cycle cost projections. Fast construction means earlier occupancy and reduced financing costs. Winter construction can proceed with few weather delays as precast components are prefabricated in heated plants. Precast prestressed concrete offers long spans, heavy load carrying capacity and shallow construction depths. Precast offers corrosion resistance, clean dust free surfaces, low maintenance and fire resistance. The appearance and aesthetic possibilities of precast offer plenty of design freedom. Quality control is assured by precast certification to CSA to A23.4 - "Precast Concrete - Materials and Construction".
Economics of precast construction
Preplanning is critical. Choosing a modular design will maximize repetition of similar elements and minimize form costs and form changes. Consult your local CPCI members for input on detailing, constructability and erection considerations. Valuable time can be gained by pretendering the precast to allow preparation of shop drawings and fabrication of members ahead of time.
Try to use standard double tees, hollowcore and solid slabs. Consult your local CPCI members for the standard sizes available in your area. Custom shapes can be used if special requirements of very large quantities will justify the cost of new forms.
Try to use standard beams, girders and columns available. Consult your local CPCI members for the standard sizes available in your area. Sometimes standard bridge girders can be adapted for use in manufacturing buildings. Lateral loads can be resisted by shear walls, frames and cross bracing. Keep connections simple and repetitive. Protect connections in wet or corrosive environments.
A precast structure must accommodate processes, equipment, cranes, monorails, mechanical systems and electrical systems. Often a modular grid of openings and sleeves or inserts is used for flexibility and to allow for ongoing changes during construction and for future modifications to the building/processes. Plan for any anticipated future expansion at the time of construction.
Precast modular sandwich wall panels are ideal when economy and speed of construction are needed. Custom sandwich wall panels can be used for more variety in colour, size and finish. Architectural precast cladding is often used for office areas or where more shape and detail is required.
The following are some major industrial projects constructed using precast concrete. Contact CPCI for more information.
- STORA, Port Hawksbury, NS - 1997
- Maple Leaf, Brandon, MB - 1998
- Steelcase, Toronto, ON - 1980
- ALCAN Smelter, Alma, QC - 1999
- Newsprint Machine Building #5, Campbell River, BC - 1982
- Union Camp Paper Machine Building, Savannah, GA - 1989
- Weyerhaeuser Container Board Plant, Valliant, OK - 1981
- Crown Zellerbach Pulp Mill Building, Camas, WA - 1982
- Federal Paper Board Pulp Mill, Riegelwood, NC - 1978
- Union Camp Machine Building #1, Eastover, SC - 1983
- Zinc Electrolytic and Melting Plant, Trail, BC - 1979
- Revere Aluminum Rolling Mill, Scottsboro, AL - 1968
- CPCI Design Manual - Edition 3
- CPCI Architectural Precast Concrete Technical Guide
- PCI Design Handbook - Edition 5
- PCI Architectural Precast Concrete - Edition 2
- Other PCI publications on structural design, connections, etc.