Structural stability must be maintained at all times during the steel erection process.
Since structural collapse is second only to falls as a cause of fatalities in this industry, stability is essential to the successful erection of any steel structure, including single-story, multi-story, and bridges. This section of the standard outlines the work practices that will prevent collapse due to lack of stability. In addition, it addresses slipping and tripping hazards and certain kinds of fall hazards encountered when working on steel structures.
A crew of steelworkers was connecting a steel beam to a steel column on the seventh level of an airport structure. The base of the column was secured to a sheer concrete wall by temporary welds to an embedded steel plate.
When the crew encountered a problem connecting the beam to the column, a decision was made to pull the top of the column one inch to the north to facilitate the connection. The pull was performed by tensioning a guy wire, using a come-along, applying a fork at the column being connected, and using a sleeper. One worker was seated on the beam that was being connected, while another was standing at the base of the column, atop the concrete wall.
When the force of the tensioning caused the temporary welds at the column base to fracture, the column collapsed, and the two workers fell to their death.
Rules for steel erection safety for multi-level structures can be found in OSHA Standard 1926.754(b).
Permanent floors: Permanent floors must be installed as the erection of structural members progresses, with no more than eight stories between the erection floor and the upper-most permanent floor.
Unfinished bolting or welding: Unfinished bolting or welding above the foundation (or the uppermost secured floor) is not permitted to exceed the lesser of:
Exceptions are allowed where structural integrity is accounted for in the design.
Safety Nets and Floors: Safety nets or a fully planked or decked floor must be maintained directly under any erection work being performed, within the lesser of:
Tripping hazards: To prevent tripping hazards, do not attach the components listed below if they project from the top flanges of beams, joists, or beam attachments until after the metal decking, or other walking/working surface, has been installed.
When shear connectors are used in the construction of composite floors, roofs and bridge decks, they must be laid out and installed after the metal decking has been installed. The metal decking will then serve as a working platform.
Shear connectors may not be installed from within a controlled decking zone (CDZ).
Workers are not be permitted to walk the top surface of any structural steel member installed after July 18, 2006 that has been coated with paint or similar material, unless all of the following are met:
It’s important to make sure the structure being erected is “plumb” or exactly vertical. The process of lining up the building elements in a precise vertical direction is called “plumbing up.”
Follow these requirements when hoisting, landing, and placing metal decking bundles:
Metal decking on roof and floor holes and openings must be installed as follows:
When metal decking holes and openings are cut, they must:
Covers for roof and floor openings must be capable of supporting, without failure, twice the weight of the employees, equipment, and materials that may be imposed on them at any one time.
All covers must be:
Installed smoke dome or skylight fixtures are not considered covers, unless they meet the appropriate strength requirements.
Where planks or metal decking around columns do not fit tightly, wire mesh, exterior plywood, or equivalent material must be installed, and must be of sufficient strength to:
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