A Biomechanical Analysis of Laying Concrete Block (The following information has been abstracted from a paper submitted to the 2nd International Symposium on Ergonomics in Building and Construction, IEA, August 2000)

Nadine Marks
Construction Safety Association of Ontario

Peter Vi
Occupational Health Clinic of Ontario Workers

A study of bricklayers laying concrete blocks was performed to determine the biomechanical stresses and metabolic demands on their low back and upper extremities during the course of a regular working day.

Utilizing the facilities of the Ontario masonry Training Center, an experienced instructor was videotaped using semisolid block in a controlled environment These results were analysis for L4/L5 trunk moment, spinal compression and shearing forces and metabolic demands.

Preliminary results indicate that over an average working day a worker will actually lift blocks for approximately 30 minutes - 1 hour ( 5-7 secs.per lift at 200 blocks per day). The rest is the time is spent on non-lifting activities i.e. scooping up the mortar, tapping the block into place, using the level, setting the line etc. Consequently, the authors divided the analysis into lifting and non-lifting activities. Analysis results indicate that it is the non-lifting activities which were found to be the higher risk activity for musculoskeletal injury compared to the lifting activity for these workers. Further on site study is to be evaluated.

Recommendations for injury prevention among these workers include focusing on non-lifting activities such as using height adjustable mortarboards when working at ground level and using elevating scaffolds to keep the materials at ergonomically acceptable heights. Additionally, limiting the size and weight of concrete blocks is recommended.



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