U. S. Department of Labor

Occupational Safety and Health Administration

Directorate of Science, Technology & Medicine

Office of Science and Technology Assessment

SHIB 05-01-2006

Safety and Health Information Bulletin

This Safety and Health Information Bulletin is

not a standard or regulation, and it creates no

new legal obligations. The Bulletin is advisory

in nature, informational in content, and is

intended to assist employers in providing a safe

and healthful workplace. Pursuant to the

Occupational Safety and Health Act, employers

must comply with hazard-specific safety and

health standards promulgated by OSHA or by a

state with an OSHA-approved state plan. In

addition, pursuant to Section 5(a)(1), the

General Duty Clause of the Act, employers

must provide their employees with a workplace

free from recognized hazards likely to cause

death or serious physical harm. Employers can

be cited for violating the General Duty Clause if

there is a recognized hazard and they do not

take reasonable steps to prevent or abate the

hazard. However, failure to implement any

recommendations in this Safety and Health

Information Bulletin is not, in itself, a violation

of the General Duty Clause. Citations can only

be based on standards, regulations, and the

General Duty Clause.

Overhead Launching Gantry Crane

Safety and Health Information Bulletin

Purpose

The purpose of this Safety and Health Information

Bulletin (SHIB) is:

1. To inform overhead launching gantry crane

users of the hazards associated with

deviating from the manufacturer’s guidelines

on the use of overhead launching gantry

cranes, such as unanticipated movement or

collapse of the structure during use;

2. To highlight that all employers using

overhead launching gantry cranes in

segmental or similar bridge construction

must comply with all manufacturer’s

guidelines, including proper anchoring of

the cranes during launching, to prevent

transversal or longitudinal movement of the

structure; and

3. To provide information that employers can

use to address these hazards.

Background

OSHA’s Toledo, Ohio, Area Office investigated a fatal

accident involving the collapse, during a launch

sequence, of an overhead launching gantry crane used

during segmental bridge construction. The equipment

involved was an overhead truss with a self-launching

under-bridge (overhead launching gantry)

manufactured by Paola De Nicola of Italy for the

construction of the Maumee River Crossing in Toledo,

Ohio (see Figures 1 and 2).
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The launching gantry is used to place concrete bridge and pier segments for elevated

roadways and bridges by spanning the distance between a finished road segment and the

next roadway pier or column. While spanning this distance, the launching gantry picks up

each bridge segment and suspends the segments from beneath the overhead truss moving

the segments into place. The segments are then epoxied together and post-tensioned into

place. Following the successful placement of the roadway segments beneath the overhead

truss, the entire launching gantry is then moved forward to the next span along its

previously launched under-bridge. The under-bridge provides a temporary bridge over the

span for the front leg of the launching gantry to travel and position the structure over the

next span. (See Figure 3)

Figure 1: General Configuration of the Overhead Launching Gantry

Manufactured by Paola De Nicola for the Maumee River Crossing.

Figure 2: Two Launching Gantries Side-by-side.
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For this particular design, the manufacturer required the use of four anchoring bars for each of the four

rear legs (sixteen total anchoring bars) and two anchoring bars for each of the two telescoping front legs

(four anchoring bars total). The anchoring bars in the rear were designed to be pre-stressed to 600 kiloNewton’s per bar (approximately 135,000 pounds of force per bar) to provide resistance to the

longitudinal and transversal forces primarily during the launching of the under-bridge. The front leg

anchors were to be pre-stressed to resist transversal forces, such as those created by wind.

Accident Investigation

The accident investigation revealed that the employer had not designed the pier segments to

accommodate each of the anchoring locations, reportedly because of congestion in the segments with

other items such as stressing cables. It was further determined that the employer used only a few

anchoring bars during the initial launches and as work progressed began using fewer and fewer anchoring

bars. On the day of the accident, there were no anchoring bars for the four rear legs and only one

anchoring bar in each of the front legs. Additionally, the front leg anchors had not been stressed to the

appropriate force and were only tightened with a wrench. A few months prior to the collapse of the

launching gantry, the employer had experienced a movement of about 2 centimeters at the rear legs

during a launch when using a total of only two rear-leg anchoring bars. The manufacturer’s instructions

provided that such movement could lead to a collapse of a launching gantry.

Figure 3: Launching Gantry with Suspended Segments.
Conclusions

OSHA’s Cranes and Derricks standard, 29

CFR 1926.550(a)(1) requires employers to

comply with the manufacturer’s

specifications and limitations applicable to

the operation of any and all cranes and

derricks.

In the event that manufacturer’s specifications

are not available, the limitations assigned to

the equipment shall be based on the

determination of a qualified engineer

competent in the field; such determinations

must be appropriately documented, recorded

and available for review, as necessary, by

affected parties and any authorities having

jurisdiction.

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Figure 4: View of the Launching Gantries after the Accident

Reference Standard

29 CFR 1926.550(a)(1) - The employer shall

comply with the manufacturer’s specifications and

limitations applicable to the operation of any and all

cranes and derricks. Where manufacturer’s

specifications are not available, the limitations

assigned to the equipment shall be based on the

determinations of a qualified engineer competent in

this field and such determinations will be

appropriately documented and recorded.

Attachments used with cranes shall not exceed the

capacity, rating, or scope recommended by the

manufacturer.

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