Precast Inc. - November/December 2008 - (Page 56) S A F E T Y & H E A LT H Safety in Prestressing Prestressing in a precast plant can be a dangerous operation and requires special training and awareness. BY GUSTAVO A. GONZALEZ he manufacture of prestressed concrete is similar to that of precast concrete. The major difference is the way in which steel reinforcement is applied to the casted parts. Many plants in the United States and Canada produce both precast and prestressed products in the same facility, and therefore all of OSHA General Industry Standards and Canadian Safety Regulations requirements apply to the manufacture of these products. While there is a specific OSHA Construction Standard, CFR 1926 Subpart Q, which covers some of the safety concerns of post-tensioned concrete (stretching the cables after concrete has been cured) and the lifting of precast members, there are no specific regulations that address the safety issues arising during the manufacture of prestressed concrete. ANSI 10.9-1997 (Rev. 2004), “Safety Requirements for Concrete and Masonry Work,” Parts 8 and 9, offers some safety guidelines to be followed during the fabrication, handling and lifting of prestressed members. The same hazards associated with a precast plant can also be found in any prestressed plant, as both manufacturing processes use the same equipment, methods and procedures. In both instances the mixing, pouring, finishing and handling operations are the same, so the same safety precautions and employee training must be in place. However, prestressing operations require additional consideration because of the great forces involved. In precast concrete, the steel reinforcement usually consists of rebar or mesh placed inside a mold or form in which the concrete mix is poured. In a prestressed operation, the steel reinforcement consists of cables or tendons placed inside a casting bed and stretched to predetermined limits before the concrete is placed. During the T stretching process of these cables, great amounts of force are placed on them, creating a hazardous and dangerous condition that requires unique safety considerations. Another important safety concern in a prestressed plant is the handling, storage and shipping of these components. Many 56 NOVEMBER/DECEMBER 2008 | PRECAST INC.
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.