In January of 2012, the Safety and Health Department launched several new initiatives designed to “target the deadly dozen hazardous activities that lead to fatalities and disabling injuries.” The focus of this article is to highlight some of the serious hazards pertaining to structural collapse of columns due to anchor bolt failure. Information obtained from the Occupational Safety and Health Administration (OSHA) and the International Association revealed that anchor bolt failure during column erection contributed to several fatalities. Following are job site illustrations and OSHA Subpart R—Steel Erection standards that depict some of the primary hazards and regulatory requirements pertaining to:
- Column-to-base plate design requiring a minimum of (4) anchor bolts;
- Notification of concrete strength from controlling contractors prior to steel erection;
- Written notification and engineer approval of modifications to anchor bolts systems;
- Column evaluation by a competent person to determine column stability.
Column-to-Base Plate Requirement for a Minimum of (4) Anchor Bolts
The structural stability of columns starts with the columns being anchored with a minimum of four anchor bolts. Serious accidents involving structural collapse have been attributed to “two-bolt” columns. During the erection of columns, the column height and size can create a lever-arm that can transfer extreme forces to the footings and anchor bolt systems. Following is the OSHA standard that requires all column-to-base plates to be designed and fabricated with a minimum of four anchor bolts to help prevent collapse.
1926.755(a)(1)—“All columns shall be anchored by a minimum of four anchor rods (anchor bolts).”
Written Notification of Concrete Strength Prior to Steel Erection
Prior to the commencement of steel erection, the steel erection contractor must receive written notification from the controlling contractor that the concrete in footings, piers and walls are either 75 percent of the intended minimum compressive design strength or sufficient strength to support the loads imposed during steel erection. The “controlling contractor is defined as a prime contractor, general contractor, construction manager or any other legal entity which has the overall responsibility for the construction of the project-its planning, quality and completion.” Following is the OSHA standard requiring written notification of concrete strength.
1926.752(b)—“A steel erection contractor shall not erect steel unless it has received written notification that the concrete in the footings, piers and walls or the mortar in the masonry piers and walls has attained either 75% of the intended minimum compressive design strength or sufficient strength to support the loads during steel erection.”
Written Notification and Approval of Modifications
Anchor bolts that have been repaired, replaced or field-modified incorrectly have attributed to column collapse and fatalities. It is important for our members to recognize a specific OSHA standard that requires the controlling contractor to provide written notice of any anchor bolts that have been repaired. Any repairs to anchor bolts must be approved by the project structural engineer of record. Following is the OSHA standard that is designed to provide written notification of anchor bolt modifications.
1926.755(b)(2)—“Prior to the erection of a column, the controlling contractor shall provide written notification to the steel erector if there has been any repair, replacement or modification of the anchor rods of that column.”
Engineer Approval for Anchor Bolt Repairs and Modifications
The photograph above illustrates anchor bolts that failed due to improper repairs using epoxy chemical bonding. This repair method was not performed with the approval of the project structural engineer of record. When anchor bolts have been repaired, replaced or field-modified it must be done correctly. Following is a specific OSHA standard that requires all repairs, replacement and field-modification of anchor bolts to be approved by the project structural engineer of record.
1926.755(b)(1)-“Anchor bolts shall not be repaired, replaced or field-modified without the approval of the project structural engineer of record.”
Column Evaluation by a Competent Person
While erecting columns, it is often necessary to install temporary guy cables to ensure stability. Several factors including anchor bolt condition, environmental conditions, site conditions, etc., may create additional hazards that would require columns to be guyed during the erection process. Following is the OSHA standard that requires all columns to be evaluated by a competent person to maintain stability.
OSHA has defined a competent person as one who is “capable of identifying existing and predictable hazards in the surroundings or working conditions, which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.”
1926.755(a)(4)—“All columns shall be evaluated by a competent person to determine whether guying or bracing is needed; if guying or bracing is needed, it shall be installed.”
Preventing Structural Collapse—The Importance of Training
The photograph above illustrates a building collapse during the steel erection process due to anchor bolt failure and the improper field repair. The Ironworkers National Training Fund has developed a special training module for apprentices and journeymen upgrading that provides specific instruction on safe methods of structural steel assembly, anchor bolt requirements, minimum concrete strength requirements, column anchorage, and written notifications from controlling contractor prior to the commencement of steel erection. This training course utilizes job site videos of structural steel assembly, color illustration manuals, and an instructor’s PowerPoint CD with photographs of specifics and is offered at our training facilities throughout the United States and Canada.
The “2012 Zero Fatality” campaign will challenge all members to “intervene and prevent unsafe conditions and unsafe acts” during the steel erection process. Anchor bolt failure and column is one of the “deadly dozen hazards” that has led to fatalities and disabling injuries. This campaign will include hard-hat stickers, gang-box stickers, and posters for training facilities and local unions. I will continue to work closely with district councils, local unions, and IMPACT Regional Advisory Boards throughout the United States and Canada to promote the International Association’s “2012 Zero Fatality” campaign by “targeting the deadly dozen hazardous activities that lead to fatalities and disabling injuries.”
May Feature Issue: “Fall Protection” Targeting One of the Deadly Dozen Hazardous Activities