Precast Inc. - July/August 2008 - (Page 19) given day, investigations into the recent collapses have begun. So far, a failed weld on one crane’s turntable is under scrutiny, and a city inspector has been arrested for taking bribes and falsely certifying small, mobile cranes for operation. After the recent tower crane collapses in New York City and because cranes are responsible for more than 20 percent of all construction fatalities, here is an overview of the federal standards for crane, gantry and hoist safety enforced by the Occupational Safety and Health Administration (OSHA). In the precast concrete industry, tower cranes are often used in erection of parking structures and high-rise buildings on restricted sites. Large mobile cranes (track or wheel mounted) are frequently used to erect precast concrete structures such as mid-rise buildings and bridges, and gantry and mobile cranes are typically seen moving precast product at manufacturing facilities. Responsibilities of site superintendent and crane operator It is important to note that with advanced technologies, cranes have increased in strength, speed, capacity, reach and sophistication. Cranes are typically the most expensive piece of large equipment on any construction site and have become indispensable workhorses in the precast concrete fabrication and erection industry. Cranes are involved in more accidents, however, than any other type of construction equipment. It is critical, therefore, that site (or project) superintendents, senior management and crane operators have a thorough understanding and knowledge of crane capacity and limitations. While not meant to serve as a comprehensive list, here are 10 important points to remember: 1. Know and thoroughly understand the crane manufacturer’s design parameters and operating guidelines. 2. The job site superintendent is responsible for all activities on the job site including crane operating conditions and safety. 3. Preplanning and coordination of all construction activities through to project completion, especially the monitoring of crane operations, are critical to job-site safety. 4. Check for overhead and electrical hazards. 5. Make sure outriggers are extended to manufacturer’s specifications and ensure a solid crane foundation. 6. Check all clearances for lifting and access. 7. Check that pinch points are guarded and that congestion around the crane is minimized as much as possible. 8. Do not modify a crane’s operating procedure or “make do” with existing equipment when faced with unexpected job-site events or conditions. 9. Ensure that the crane is suitable for the task and adequate for site conditions. 10. Remember that improper crane setup results in 50 percent of all construction crane accidents. More specifically, the site superintendent and crane operator must understand and be knowledgeable of preshift inspection protocols and these 10 items: 1. Anti-two-block devices (“two-blocking” is a condition in which the lower load block or hook assembly comes in contact with the upper load block or boom point sheave assembly) 2. Load-moment indicators 3. Mechanical level 4. Boom angle indicator 5. Load indicating devices 6. Crane load charts 7. Outriggers and pad supports 8. Radius measurements 9. Lifting devices, such as slings and bars 10. Load calculations Keep in mind that all crane manufacturers’ specifications and load charts were developed for ideal conditions and using new equipment – JULY/AUGUST 2008 | WWW.PRECAST.ORG dreamstime.com 19 http://dreamstime.com http://www.precast.org
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