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OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov.
November 17, 2004
Gary R. Christiansen
Central Regional Safety Director
800 E Northwest Hwy., Suite 200
Palatine, IL 60074
Re: Anchorage system under §1926.755(a)(1)
Dear Mr. Christiansen:
This is in response to your fax dated March 2, 2004, and supplemental information provided in your June 24 and July 21, 2004, correspondence by e-mail to the Occupational Safety and Health Administration (OSHA). You describe an anchoring system used in erecting columns and would like to know whether this system is in compliance with §1926.755(a)(1).
We have paraphrased your question as follows:
Question: Scenario: Column footings are poured, and four anchor rods are embedded with the threads facing up. After the concrete has cured to the required degree, a 9½-inch high steel sleeve with a welded base plate is attached to the footing with four bolts. The top bolts are tightened, and the area under the sleeve's base plate is grouted.
Using a crane, the column is raised, and the bottom of the column is slipped into the sleeve. There is a 1/8th-inch gap on all four sides between the sleeve and the column. The column is not welded to the sleeve until just before the floor and roof decking are installed. This anchorage system is designed to resist a 300-pound eccentric load (see illustration below).
[NOTE: Illustration is not to scale.]
Is this system in compliance with §1926.755(a)(1)?
Requirements under §1926.755(a)(1)
Section 1926.755(a)(1) states:
All columns shall be anchored by a minimum of 4 anchor rods (anchor bolts).
The purpose of §1926.755(a)(1) is to help prevent column collapse during the erection process and thereby protect ironworkers who are connecting beams on top of the column (see volume 66 of the Federal Register, page 5222, Jan.18, 2001). The requirement for four anchor bolts does this by providing a stronger anchorage that will resist forces in all directions around the column. In the system you describe, once the column is placed in the sleeve, the column is anchored through the sleeve to the four anchor rods that attach the sleeve to the footing. The anchorage's four anchor rods prevent column collapse in all four directions. The anchorage therefore meets the requirements of §1926.755(a)(1).
General Duty Clause requirements
In further conversations you noted that because the column is not welded until just before the sheet metal deck is placed, the 1/8th-inch gap between the column and the sleeve allows some lateral movement of the column while the beams are attached. For a column 30 feet high, the movement at the top of the column would be about 4 inches in each direction. In that case, the total sway along one axis (for example, east to west) could be as much as 8 inches. For a column 45 feet high, the movement would be about 6 inches in each direction, for a total of 12 inches of sway along an axis. You also indicated that when your company erects these columns, at no time are workers on the columns -- the connectors work from scissor lifts.
Although the anchorage system is in compliance with §1926.755(a)(1),1 the lateral movement created by the 1/8th-inch gap introduces a new hazard that is not addressed by the steel erection standard. The lateral movement of the column inside the sleeve would pose a safety hazard to workers on the column doing connecting work. While column sway is not unusual, what is unusual about this system is that a swaying column will suddenly come to a stop as it hits the sleeve.
In the more traditional system of a base plate connected directly to the column base, the column's sway slows to a stop before oscillating back. The sudden stop against the sleeve in your system could jar the connector and potentially cause the connector to lose his or her grip and to fall. Section 5(a)(1) of the OSH Act ("General Duty clause") states that each employer:
shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.
In our view, use of this system with an ironworker on the column would constitute a violation of the General Duty clause unless measures were instituted to prevent the hazard of the swaying column stopping suddenly against the sleeve. However, you indicate that when you use this system no workers are physically on the columns performing connecting work; instead, the work is done from scissor lifts. In that case there would be no employee exposure to the safety hazard caused by the lateral movement of the column. Where there is no employee exposure the hazard is not citable.
In sum, the use of the sleeve to anchor the column would not be in violation of §1926.755(a)(1). While the jarring action in this system caused by the sudden stopping of column sway is a hazard under the General Duty Clause, so long as there is no employee exposure to that hazard, there would be no citable violation.
If you need any additional information, please contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, Office of Construction Standards and Guidance, fax # 202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.
Russell B. Swanson, Director
Directorate of Construction
1 Since you state that the anchorage system is designed to resist a 300-pound eccentric load, it would satisfy the strength requirements of §1926.755(a)(2). [ back to text ]