Concrete Reinforcement Workers Research Articles

Model-based mechanical design of a passive lower-limb exoskeleton for assisting workers in shotcrete projection

Despite the current industrial trend towards automation, many workers are still daily exposed to heavy loads during their duties. Regarding the construction industry, the shotcrete projection results in a particularly arduous whole-body effort for the so-called “concrete reinforcement workers”. In this paper, the design of a passive robotic human assistance tool to assist workers in dealing with the specific task of shotcrete projection will be described. If the design of an effective aid plays a crucial role in improving the job’s quality, following the guidelines given by the French company Eiffage Infrastructures; besides, the acceptance of the proposed solution shall have special consideration. Therefore, starting from an in-site assessment of the scenario, the presented solution has been profoundly adjusted to address the issues coming from this particular task. The exoskeleton adaptability to different lower-limb activities has been preserved without lowering its comfort during daily life in the working area. The developed solution’s operation range has been specifically optimized to assist the worker during specific efforts without hindering the other movements.

Evaluation of team lifting on work demands, workload and workers' evaluation: An observational field study

The objective of this study was to assess differences in work demands, energetic workload and workers’ discomfort and physical effort in two regularly observable workdays in ironwork; one where loads up to 50kg were handled with two persons manually (T50) and one where loads up to 100kg were handled manually with four persons (T100). Differences between these typical workdays were assessed with an observational within-subject field study of 10 ironworkers. No significant differences were found for work demands, energetic workload or discomfort between T50 and T100 workdays. During team lifts, load mass exceeded 25kg per person in 57% (T50 workday) and 68% (T100 workday) of the lifts. Seven ironworkers rated team lifting with two persons as less physically demanding compared with lifting with four persons. When loads heavier than 25kg are lifted manually with a team, regulations of the maximum mass weight are frequently violated. Statement of relevanceLoads heavier than 25kg are frequently lifted during concrete reinforcement work and should be lifted by a team of persons. However, the field study showed that loads above 25kg are most of the time not lifted with the appropriate number of workers. Therefore, loads heavier than 25kg should be lifted mechanically.

A field study investigating the effects of a rebar-tying machine on trunk flexion, tool usability and productivity

A field study with a before-and-after experimental design was conducted to evaluate the potential reduction in the risk of musculoskeletal injuries to rodworkers when using an automatic rebar-tying machine. Eleven rodworkers participated in this experiment. All dependent variables (trunk posture, rebar-tying time and responses to a usability questionnaire) were first measured before introducing the rebar-tying machine and then after 3 months of usage all dependent variables were measured again. The results of the study indicated that working with a rebar-tying machine significantly reduced the magnitude, frequency and duration of exposure to awkward trunk posture. Tying time was reduced when participants used the machine. The usability questionnaire indicated that most participants preferred to use the rebar-tying machine for ground-level rebar construction. The field study also revealed that the rebar-tying machine is not limited to the reinforcing trade. The machine can be used for other purposes, such as tying electrical conduit and attaching radiant heat tube to steel mesh. Based on trunk posture exposure, rebar-tying time, usability and transferability, it is concluded that the rebar-tying machine can be an effective tool to reduce the frequency and duration of severe trunk flexion, improve usability and increase productivity among concrete reinforcement workers.

Effects of Rebar Tying Machine on Trunk Flexion and Productivity

A before-and-after experimental design was conducted to evaluate the potential reduction in the risk of musculoskeletal injuries to concrete reinforcement workers when using an automatic rebar tying machine. Eleven (11) concrete reinforcement workers participated in this experiment. All dependent variables (trunk posture, and rebar tying time) were measured before and after implementing the rebar tying machine. The results of the study indicated that working with a rebar tying machine significantly reduced the magnitude and duration of exposure to awkward trunk posture. Tying time was reduced when participants used the machine. Based on trunk posture exposure and rebar tying time, it is concluded that the rebar tying machine can be an effective tool to reduce the frequency and duration of severe trunk flexion and increase productivity among concrete reinforcement workers.

Algorithms for Reducing the Waste Rate of Reinforcement Bars

Loss of rebars can be minimized with minimum use of discrete bars in market length. In order to achieve this goal, the accurate and detailed information of rebars is extracted, followed by both rapid and efficient bar combination. No paper has dealt directly with the reduction of rebar waste rates, although many researches have proposed indirect approaches to enhance productivity, constructability, safety and quality in the process of concrete reinforcement work. This paper, therefore, was prepared with the aim of developing algorithms to supply rebars required to minimize material waste during cutting and bending of discrete bars in rebar shops. At the same time, this study presented an automatic rebar detailing concept, a logical process of rebar combination with pertinent algorithms and binary search algorithm for bar data to implement the proposed topic. The effectiveness of the suggested algorithms was validated by case studies.

Quantification of ergonomic hazards for ironworkers performing concrete reinforcement tasks during heavy highway construction.

A study was conducted to assess the ergonomic hazards of ironwork job tasks associated with concrete reinforcement work at a large highway construction site. PATH (posture, activity, tools, and handling) analysis, a work-sampling method, was used to provide task-based estimates of the percentage of time ironworkers spent in specified postures of the trunk, arms, and legs; performed activities; used tools; and handled loads. A total of 2128 PATH observations were made of 17 ironworkers performing 5 job tasks: (1) ground-level reinforcement bar (rebar) construction, (2) wall rebar construction, (3) ventilation rebar construction, (4) preparation work, and (5) supervising. Nonneutral trunk postures were observed frequently (exceeding 30%) and manual material handling (MMH) was the most commonly observed activity (exceeding 20%) for all job tasks except supervising. The percentage of time workers spent in specific postures, activities performed, tool use, and MMH activities differed significantly between the five main job tasks, even when supervising was excluded from the analysis. It was concluded that ironworkers are exposed to significant ergonomic hazards when performing concrete reinforcing tasks, and that opportunities exist for the implementation of ergonomic interventions. Further, the results of this study can be used to target specific hazardous tasks for ergonomic interventions and confirms the need to use a task-based exposure assessment strategy to properly assess ergonomic risk profiles for nonstructured jobs such as construction.

An evaluation of manual materials handling in highway construction work

Construction work is generally described as strenuous but few systematic characterizations of physical load have been published to date. PATH (Posture, Activities, Tools and Handling) is an ergonomic assessment method used to measure the frequency of exposure (as a proportion of observations) to manual materials handling (MMH) activities and other exposures for construction and other non-routinized work. Observations of loads handled, body postures, tools and materials handled and hand grasps are available for further description of MMH activities. PATH has been used to characterize manual handling by iron workers (in concrete reinforcement work), carpenters (in form construction) and laborers (in the construction of utilities pits) during highway construction operations. Of these trades, the iron workers were the most frequently observed in heavy MMH activities (involving at least 13.5 kg), and they often lifted in twisted or laterally bent trunk postures. Heavy MMH activities by laborers most frequently involved the handling of boards used to construct the pit walls. Little heavy MMH (at least 22.7 kg) was observed in the carpentry tasks. MMH requirements varied greatly among tasks within each construction operation, demonstrating the importance of a task-based assessment of MMH exposures. Analysis of subsets of data on the iron workers and the carpenters showed that, in some cases, task and worker were important sources of variance. For almost all variables, the error term (interpreted primarily as day-to-day differences in exposure) was the largest source of variance. Therefore, an evaluation of multiple workers over long time periods for specific tasks is necessary for a reliable characterization of MMH requirements and other ergonomic exposures in highway construction work. Relevance to industry The methods described in this paper allow the systematic evaluation of MMH activities in highway construction and other types of non-routinized work. These can be used to identify job tasks having potentially hazardous MMH exposures, and to provide information needed for the appropriate re-design of tasks or materials to reduce physical loading on the musculoskeletal system.

Reanalysis of the occurrence of back pain among construction workers: modelling for the interdependent effects of heavy physical work, earlier back accidents, and aging.

OBJECTIVES: To re-examine the relation between heavy physical work and the occurrence of sciatic pain among construction workers reported previously to be absent in an epidemiological study. METHODS-Poisson log linear...

Radiographically Detectable Degenerative Changes of the Lumbar Spine Among Concrete Reinforcement Workers and House Painters

In this study of lumbar degeneration and the role of mechanical loading in its development, lateral lumbar radiographs of 216 concrete reinforcement workers and 201 house painters aged 25-54 years were examined. Disc space narrowing occurred at about 10 years and spondylophytes at about 5 years younger age in the former than in the latter group. Risk ratios (RR) were estimated from the regression coefficients of logistic regression models. RR for the univariate effect of occupation on disc space narrowing was 1.8, and adjustment for age, earlier back accidents, height, body mass index and smoking had only a minor effect on this relationship, adjusted RR 1.8. The crude RR for spondylophytes was 1.5, and the adjusted RR 1.6. Earlier back accidents showed a significant univariate relationship with DSN, but in multivariate analysis this variate did not retain its significance. It was concluded that heavy physical work enhances the degenerative process of the lumbar spine. Materials handling and postural loading are proposed to be occupational factors of importance in the development of both disc space narrowing and spondylophytes.

Predictors of sciatic pain among concrete reinforcement workers and house painters--a five-year follow-up.

In a study of the association of occupation and several other determinants with the occurrence of sciatic pain, 167 concrete reinforcement workers and 161 house painters were followed for five years. Base-line data were obtained with a questionnaire, an interview on back symptoms, a clinical examination, and a radiograph of the lumbar spine. Follow-up data on back symptoms were obtained with a postal questionnaire. Concrete reinforcement work was associated with an increase in the risk of sciatic pain, in both a cross-sectional and a prospective study. Reported back accidents contributed to the risk of sciatic pain. Previous history of back symptoms was the most powerful predictor of sciatic pain prospectively. Degenerative changes were related to sciatic pain in retrospect, but prospectively this relationship was weaker. Body height and history of stress episodes showed some association with sciatic pain; abdominal muscle strength, body mass index, and smoking did not; and back muscle strength was associated only retrospectively.

Radiographically detectable lumbar degenerative changes as risk indicators of back pain. A cross-sectional epidemiologic study of concrete reinforcement workers and house painters.

The association between radiographically detectable degenerative changes in the lumbar spine and back symptoms was studied, along with the possible effect of occupational work load. The subjects were 216 concrete reinforcement workers and 201 house painters. A questionnaire provided information on work history and earlier back accidents, and a standardized interview produced data on back symptoms. The occurrence of disc space narrowing, anterior and posterior spondylophytes, and end-plate sclerosis was recorded separately for each intervertebral space from lateral lumbar radiographs. Moderate to severe degenerative changes were associated with increased risk of sciatic pain but not with the occurrence of lumbago or nonspecific back pain. The different types of degenerative changes provided no further information. In a multivariate logistic regression analysis degenerative changes and earlier back accidents were significant independent predictors of sciatic pain. When these two variates were allowed for, the effect of occupation was not significant.

Accidents and minor accidents of the Musculoskeletal system in heavy (concrete reinforcement work) and light (painting) construction work

Background: Unintentional injuries are the leading cause of death for children and youth aged 1–19 in the United States. The purpose of this report is to describe how unintentional injury death rates among children and youth aged 0–19 years have changed during 2010–2019. Method: CDC analyzed 2010–2019 data from the National Vital Statistics System (NVSS) to determine two-year average annual number and rate of unintentional injury deaths for children and youth aged 0–19 years by sex, age group, race/ethnicity, mechanism, county urbanization level, and state. Results: From 2010–2011 to 2018–2019, unintentional injury death rates decreased 11% overall—representing over 1,100 fewer annual deaths. However, rates increased among some groups—including an increase in deaths due to suffocation among infants (20%) and increases in motor-vehicle traffic deaths among Black children (9%) and poisoning deaths among Black (37%) and Hispanic (50%) children. In 2018–2019, rates were higher for males than females (11.3 vs. 6.6 per 100,000 population), children aged < 1 and 15–19 years (31.9 and 16.8 per 100,000) than other age groups, among American Indian or Alaska Native (AIAN) and Blacks than Whites (19.4 and 12.4 vs. 9.0 per 100,000), motor-vehicle traffic (MVT) than other causes of injury (4.0 per 100,000), and rates increased as rurality increased (6.8 most urban [large central metro] vs. 17.8 most rural [non-core/non-metro] per 100,000). From 2010–2011 to 2018–2019, 49 states plus DC had stable or decreasing unintentional injury death rates; death rates increased only in California (8%)—driven by poisoning deaths. Conclusion and Practical Application: While the overall injury death rates improved, certain subgroups and their caregivers can benefit from focused prevention strategies, including infants and Black, Hispanic, and AIAN children. Focusing effective strategies to reduce suffocation, MVT, and poisoning deaths among those at disproportionate risk could further reduce unintentional injury deaths among children and youth in the next decade.

Muscular strain in ‘heavy’ and ‘light’ building work

In this Finnish study, the causes and frequency of musculoskeletal strain among concrete reinforcement workers and painters on house maintenance are analysed from observations at 30s intervals, from accident report forms and from interviews about unreported minor accidents. Various measures are then suggested to prevent the problems revealed, including careful work planning and site layout, and care over means of access to the work point.

Accidents and minor accidents of the musculoskeletal system in heavy (concrete reinforcement work) and light (painting) construction work

Niskanen, T., 1985. Accidents and minor accidents of the musculoskeletal system in heavy (concrete reinforcement work) and light (painting) construction work. Journal of Occupational Accidents, 7: 17–32. The aim of this study was to clarify the differences between concrete reinforcement workers and painters in the frequency, causes, and types of accidents and minor accidents affecting the musculoskeletal system. Accident report forms sent by construction firms to insurance companies were analyzed in detail. Accidents led to at least a 3-day absence from work. The incidence rate (accidents × 1,000/number of workers) of accidents affecting the musculoskeletal system was four times as high among the reinforcement workers (124) than among the painters (30). Minor accidents affecting the musculoskeletal system were reported five times more frequently by the reinforcement workers (1.9 minor accidents/1,000 workhours) than by the painters (0.4 minor accidents/1,000 workhours). Altogether 440 man months of reinforcement workers and 429 man months of painters were covered. The accidents and minor accidents were classified according to the following categories: work phase; work posture/work movement at moment of occurrence; ultimate event of occurrence; the part of body injured; and the injury.

Back pain and heavy physical work: a comparative study of concrete reinforcement workers and maintenance house painters.

In an investigation of the effect of heavy physical work on the back 217 concrete reinforcement workers aged 25-54 and a reference group of 202 house painters of similar age were interviewed about their back symptoms. Data on occupational history, accidents, and leisure time activities were collected with a questionnaire. The cumulative incidence rate of sciatic pain was significantly higher among the reinforcement workers than the painters. As regards the occurrence of lumbago and non-specific back pain, however, the groups were alike. In both occupational groups sciatic pain during the previous 12 months was associated with earlier back accidents (odds ratio 2.8, 95% confidence interval 1.8-4.5). The accident rate of the reinforcement workers was higher than that of the painters, and this difference seemed to explain their higher rate of sciatic pain.

Knee degeneration in concrete reinforcement workers.

The loads on the knees in concrete reinforcement work and maintenance painting were analysed on eight construction work sites. A total of 352 reinforcement workers and 231 painters. Finnish men aged 20-64, were clinically and radiologically examined to determine the condition of the knee joints in active workers. The loads on the knees and the occurrence of minor injuries and accidents were higher in reinforcement work than in painting, but the occurrence of symptoms, clinical signs, and radiological findings was equally common in both groups. Reinforcement work seemed to provoke more symptoms from degenerated knees than painting.

Study of concrete reinforcement workers and maintenance house painters: Musculoskeletal strain in work

The objective of this study was to find out to what extent the musculoskeletal system of concrete reinforcement workers and maintenance house painters is strained by poor postures, by the lifting of heavy loads, by accidents and by unexpected or sudden movements which cause minor injuries (microtrauma). Observations of both the work postures of concrete reinforcement workers and of the loads they lifted were recorded at sites where two dwellings, two office buildings and two bridges were being built. Observations of both the work postures of maintenance house painters and of the loads they lifted were recorded at two sites where maintenance house painting was being done. Minor accidents likely to have strained the musculoskeletal system were also recorded. Each site was observed for about 30 hours. In addition, interviews were conducted to study the occurrence of minor accidents. Accident report forms were analyzed in order to study accidents which resulted in injury to the musculoskeletal system. The results of this study show that musculoskeletal strain in reinforcement work and in maintenance house painting can be decreased by technical measures.

Radiologically detectable lumbar disc degeneration in concrete reinforcement workers.

Two hundred and ninety-five male Finnish concrete reinforcement workers, aged 19 to 64 years and engaged in heavy physical work including prolonged stooping, were radiologically examined by antero-posterior and lateral views of the lumbar spine while they were standing. The findings of lumbar disc degeneration were classified as none, slight, moderate or severe. The prevalence and degree of radiologically detectable lumbar disc degeneration depended strongly on age and increased especially rapidly from 40 to 44 years on. Lumbar disc degeneration showed an age-independent association to both a history of lumbago (chi2 = 10.5, p less than 0.01) and a history of sciatica (chi2 = 11.8, p less than 0.001). When disc degeneration was compared to reports of stiffness, fatigue, ache, and sharp pain in the back during an ordinary workday, no statistically significant associations were found, while disc degeneration was found to be slightly more common (chi2 = 4.6, p less than0.05) in the men reporting back symptoms as they bent down than in the men who did not report such symptoms. No association between length of exposure to static and dynamic back loads in reinforcement work and the prevalence of lumbar disc degeneration could be established, but definite conclusions on the possible effect of reinforcement work on the lumbar spine could not be drawn from the data.

Restriction and pain during forward bending in concrete reinforcement workers.

Two hundred and ninety-five male Finnish concrete reinforoement workers, aged 19-64 years and engaged in heavy physical work including prolonged stooping, were clinically examined in a cross-sectional study. Restriction of lumbar flexion was found in 38% of the men, and pain during forward bending in 19%. Restriction of lumbar flexion was strongly related to age, while pain during forward bending showed a weaker association. A history of sciatica was more common in the men with restriction during forward bending (chi 2 =6.0, P&lt;0.05) and in the men with pain during forward bending (chi 2 =17.2, P&lt;0.001) than in the men without. Restricted lumbar flexion was related to diminished back muscle performance capacity (chi 2 = 18.7, P&lt;0.001) and straight abdominal muscle performance capacity (chi 2 = 28.0, P&lt;0.001). Pain during forward bending was also related to diminished back muscle (chi 2 =25.3, P&lt;0.001) and straight abdomina,l muscle (chi 2 = 21.2, P&lt;0.0(1) performanoe capacity. The prevalence of radiologically detectable lumbar disc degeneration was associated with restricted lumbar flexion (chi 2 = 20.2, P&lt;0.001). Comparison of the occurrence of restricted lumbar flexion and pain during forward bending to length of reinforcement work experience showed no relation I3fter adjustment for age. When reinforcement workers were compared to computer technicians, restricted lumbar flexion was equally common in both groups, while the occurrenoe of pain during forward bending was morecommon among reinforcement workers (chi 2 = 8.6, P&lt;0.01).

Diminished dynamic performance capacity of back and abdominal muscles in concrete reinforcement workers.

The dynamic performance capacoty of back and straight abdominal muscles was clinically examined examined in 295 male Finnish concrete reinforcement workers aged 19 to 64 years and engaged in heavy physical work including prolonged stooping. In 24% of the men both back and straight abdominal muscle performance capacity was reduced, in 18% only the capacity of the straight abdominal muscles, and in 4% only the performanoe of the back muscle. The prevalence of diminished trunk muscle performance capacity increased rapidly with age. Diminishhed back muscle performance capacity was associated with a history of sciatica (chi 2 = 16.9, P&lt;0.001) and diminished performance capacity of the straight abdominal muscles with a history of lumbago (chi 2 = 5.9, P&lt;0.02) after adjustment fur age. Diminished back muscle performance was assocated with backache (chi 2 = 16.9, P&lt;0.001) and sharp pain. In the back (chi 2 = 4.5, P&lt;0.05) during an ordinary workday, as was also dominished performanoe of the straight abdominal muscles (chi 2 = 23.8, P&lt;0.001 and chi 2 = 7.3, P&lt;0.01, respectively). No association between length of exposure to the back loads in reinforcement worikand the prevalence of dimfinished trunk muscle pedormance capacity could be established.