Solution Summary: Rebar Positioning Device
The rebar positioning device is an engineering control that may help reduce overhead work and stressful hand & wrist activity. Traditional wall construction involves setting the rebar and repeatedly lifting concrete masonry units (CMUs) up and over the rebar. A rebar positioning device is placed between the CMUs during construction of a wall. This method allows a bricklayer to place rebar within a wall after multiple courses have been completed.
All rebar positioning devices are placed into partially constructed walls (Figure 1). There are various makes and models of rebar positioning devices.
Figure 1. Core-Lock rebar positioning device is inserted into the partially finished wall.
Core-Lock rebar positioning devices are made of 9 gauge wire and are positioned 11/4 inch deep into the CMU instead of on top (Figure 2). Various models are available to hold 2 or 4 rebar and to fit both 8 inch and 12 inch CMUs.
Figure 2. Core-Lock rebar positioning device.
RB rebar positioning devices are constructed of 9 gauge wire and have a Z-shaped design (Figure 3). There are various models available which can hold either 2 or 4 rebar and fit CMUs of 6, 8, 10 or 12 inches.
Figure 3. RB rebar positioning device. (Photo courtesy of Hohmann & Barnard, Inc.)
The Steel-Wich™ original telescoping rebar positioner (TRP™) is made of galvanized wire (Figure 4). TRP comes in 3 sizes which can accommodate #3, #4, #5,#6 ,#7, and #8 rebar.
Figure 4. Steel-Wich™ TRP™ (Photo courtesy of Steel-Wich, Inc.)
Overhead work can cause musculoskeletal disorders (MSDs) such as shoulder muscle strains; tendonitis, which is inflammation of the tendons; or rotator cuff tears, which is a rupture of a shoulder tendon. The rebar positioning device can help reduce overhead work by eliminating the need to lift the CMUs over the preset rebar. Instead, the rebar can be placed after the wall is constructed.
Stressful hand & wrist activity can cause MSDs such as muscle strains; tendonitis, which is inflammation of elbow and wrist tendons; or carpal tunnel syndrome, which is compression of a wrist nerve, resulting in finger numbness and loss of hand strength. The rebar positioning device can help reduce stressful hand & wrist activity by eliminating the need to tie rebar.
How Risks are Reduced:
A rebar positioning device minimizes the amount of overhead work since bricklayers do not have to lift CMU over rebar. Instead, rebar is inserted into the wall after it is built. In addition, the rebar positioning device eliminates the need to tie rebar, which reduces stressful hand and wrist activity.
Hess et al. (2012) found peak shoulder flexion was significantly less using rebar positioners compared with the traditional method of lifting CMU over rebar. Also, lifting the CMU overhead was significantly reduced using the rebar positioner method.
A manufacturer states, “[the Steel-Wich rebar positioning device] eliminates overhead lifting of heavy block over rebar, promoting ergonomics, increasing job site safety, and helping to prevent impalement injury.”
Safety and health experts believe rebar positioning devices will help to reduce overhead work and stressful hand & wrist activity. Research has shown that workers who perform repeated activities above shoulder level are at greater risk of sustaining shoulder musculoskeletal disorders. Studies have also reported a decrease in low back pain and stress if materials are lifted at or near waist height, instead of lifting overhead. Rebar positioning devices help the bricklayer keep the weight of the CMUs at or near waist level.
Forceful and repetitive hand and wrist activities and extreme hand/wrist postures may cause hand, wrist, and elbow musculoskeletal disorders, including tendonitis. Rebar positioning devices reduce the hand and wrist stress from holding blocks while lifting overhead. Additionally, they eliminate the forceful and repetitive activity of tying the rebar.
Effects on Productivity:
A rebar positioning device may increase productivity by reducing fatigue and reducing the amount of time needed to build a wall.
Using a rebar positioning device reduces the need to cap the protruding rebar which can prevent impalement as required by standard, 29 CFR 1926.701(b). This standard states, “all protruding reinforcing steel, onto and into which employees could fall, shall be guarded to eliminate the hazard of impalement."
Dan Anton, PT, PhD, ATC; and Jesse Brouwer, SPT – Eastern Washington University
Core-Lock Rebar Positioners
To obtain information, visit Core-Lock or contact 1-800-441-8359
RB Rebar Positioners
To obtain information, visit Hohmann & Barnard or contact 1-800-645-0616