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INTRODUCTION: Several studies have assessed and validated the impact of exoskeletons on back and shoulder muscle activation; however, limited research has explored the role that exoskeletons could play in mitigating lower arm-related disorders. This study assessed the impact of Ironhand, an active hand exoskeleton (H-EXO) designed to reduce grip force exertion, on worker exertion levels using a two-phase experimental design. METHOD: Ten male participants performed a controlled, simulated drilling activity, while three male participants completed an uncontrolled concrete demolition activity. The impact of the exoskeleton was assessed in terms of muscle activity across three different muscles using electromyography (EMG), perceived exertion, and perceived effectiveness. RESULTS: Results indicate that peak muscle activation decreased across the target muscle group when the H-EXO was used, with the greatest reduction (27%) observed in the Extensor Carpi Radialis (ECR). Using the exoskeleton in controlled conditions did not significantly influence perceived exertion levels. Users indicated that the H-EXO was a valuable technology and expressed willingness to use it for future tasks. PRACTICAL APPLICATIONS: This study showcases how glove-based exoskeletons can potentially reduce wrist-related disorders, thereby improving safety and productivity among workers. Future work should assess the impact of the H-EXO in various tasks, different work environments and configurations, and among diverse user groups.

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Whole-body fatigue (WBF) presents a concerning risk to construction workers, which can impact function and ultimately lead to accidents and diminished productivity. This study proposes a new WBF monitoring technique by applying the Critical Power (CP) model, a bioenergetic model, with a wrist-worn heart rate sensor. The authors modified the CP model to calculate WBF from the percentage of heart rate reserve (%HRR) and generated a personalized model via WBF perception surveys. Data were collected for two days from 33 workers at four construction sites. The results showed that the proposed technique can monitor field workers' perceived WBF with a mean absolute error of 12.8% and Spearman correlation coefficient of 0.83. This study, therefore, demonstrates the viability of wearable WBF monitoring on construction sites to support programs aimed at improving workplace safety and productivity.

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Tunnel boring machines (TBMs) are used to excavate tunnels in a manner where the rock is constantly penetrated with rotating cutter heads. Fine particles of the rock minerals are thereby generated. Workers on and in the vicinity of the TBM are exposed to particulate matter (PM) consisting of bedrock minerals including α-quartz. Exposure to respirable α-quartz remains a concern because of the respiratory diseases associated with this exposure. The particle size distribution of PM and α-quartz is of special importance because of its influence on adverse health effects, monitoring and control strategies as well as accurate quantification of α-quartz concentrations. The major aim of our study was therefore to investigate the particle size distribution of airborne PM and α-quartz generated during tunnel excavation using TBMs in an area dominated by gneiss, a metamorphic type of rock. Sioutas cascade impactors were used to collect personal samples on 3 separate days. The impactor fractionates the dust in 5 size fractions, from 10 µm down to below 0.25 µm. The filters were weighted, and the α-quartz concentrations were quantified using X-ray diffraction (XRD) analysis and the NIOSH 7500 method on the 5 size fractions. Other minerals were determined using Rietveld refinement XRD analysis. The size and elemental composition of individual particles were investigated by scanning electron microscopy. The majority of PM mass was collected on the first 3 stages (aerodynamic diameter = 10 to 0.5 µm) of the Sioutas cascade impactor. No observable differences were found for the size distribution of the collected PM and α-quartz for the 3 sampling days nor the various work tasks. However, the α-quartz proportion varied for the 3 sampling days demonstrating a dependence on geology. The collected α-quartz consisted of more particles with sizes below 1 µm than the calibration material, which most likely affected the accuracy of the measured respirable α-quartz concentrations. This potential systematic error is important to keep in mind when analyzing α-quartz from occupational samples. Knowledge of the particle size distribution is also important for control measures, which should target particle sizes that efficiently capture the respirable α-quartz concentration.

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Three-dimensional intelligent engineering management and control systems (EMCS) based on the browser/server (B/S) model are an important part of intelligent engineering development. These systems are used for solving the difficulties encountered in engineering management with frequent cross-specialties and are vital tools for data exchange and service sharing among multiple departments. Currently, most engineering management and control systems are based on service-oriented architectures (SOAs). The integration mechanism and high coupling of SOAs leads to the reduction in system expansibility, service quality and service safety of the engineering system, making it difficult for these architectures to serve the construction of long-span valve hall engineering. To address these concerns, the management and application technology of the multidisciplinary data of valve hall engineering based on a microservice architecture (MSA) is proposed to improve the management efficiency of engineering data. A 3D integration modeling method for valve hall engineering structures and geological environments is proposed to establish the topological association between engineering structures and geological environments, without increasing the amount of model data required. A 3D intelligent engineering management and control technology for the entire process of the construction of long-span valve hall engineering is proposed, which realizes the entire process simulation and control of engineering construction based on WebGL technology. Accordingly, a three-dimensional intelligent engineering management and control system for the entire construction process of a long-span valve hall project in Southeast China is established, which can effectively manage and apply the data, display and analyze the three-dimensional model, and control and make decisions regarding the construction schedule. This study provides support for the construction of "smart engineering", promotes information communication and transmission between different project units, and speeds up the transformation from traditional construction management relying on drawings to three-dimensional intelligent construction management based on cloud services.

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INTRODUCTION: Nail guns are commonly used in the construction industry. They represent an occupational hazard, and in the context of mental illness can pose a threat to life. AIM: To determine the number of patients admitted to Auckland City Hospital (ACH) with a nail gun injury, and to review the current New Zealand legislation surrounding nail guns. METHODS: A 25-year retrospective review of patients admitted to ACH with a nail gun injury was performed by searching the ACH Trauma Registry. New Zealand legislation was reviewed. RESULTS: Between 1994 and 2019, 45 patients were admitted to ACH with a nail gun injury. Two subgroups were identified: 31% with an intentional injury; 69% with an unintentional injury. All patients were male. The mean age was 36.3. Patients with an intentional injury had a higher mortality rate (21.4% vs 9.5%), Injury Severity Scores (24.2 vs 3.4) and ICU admission rate (50% vs 3%) and required more intensive post-injury care when compared to unintentional injuries. There is currently no legislation in New Zealand specifically governing the use of nail guns. Only powder-actuated nail guns require certification. CONCLUSION: The continued occurrence of unintentional nail gun injuries and the high lethality of intentional injuries represent two distinct areas of concern. The Government should publish guidance aimed at improving safety and reducing the rate of intentional injury.

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The efficacy of post-tensioned metal straps PTMS, wrapped around steel channels anchored to normal reinforced concrete (R.C) beams is tested in increasing the flexural capacity of the beams. For this purpose, nine normal R.C beams with dimensions of 160 mm x 240 mm x 2100 mm are constructed to fail in bending. The location and the number of the straps are considered as the main variable. It is found that using PTMS can enhance the load-carrying capacity of the beam by 29% to 63%. The decisive factors affecting the increase are the location of the straps (at the bottom or sides), shape of the flange and web edges (squared or rounded) and alignment of the flanges (vertical or inclined). A complete guide can be found in the paper as it is a novel method of strengthening beams which can be applied to the beams cast in place with integral slabs.

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Ante la emergencia COVID-19, la OPS y UNOPS presentan en este documento diversas medidas de prevención para evitar el contagio y la propagación en zonas de construcción.

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BACKGROUND: Falls are caused by difficulties in maintaining stable posture or center of pressure (COP). Studies on construction-related falls and their prevention are limitedOBJECTIVE:To propose a fall prevention index (FPI) based on the working environment at height (with or without a handrail) and experience of workers on movable scaffolds. METHODS: Thirty participants were enrolled, and their COP distances were measured at the time of falling in the anterior-posterior (AP), mediolateral (ML), and diagonal directions. RESULTS: The probability of falling in the diagonal direction is almost zero for workers with more than 20 years of experience and that in the AP direction is almost zero for workers with up to 30 years of experience. There was almost zero probability of falling in the ML direction for workers with >15 years of experience. This index can be used as a tool for predicting the risk of falls, screening workers, and implementing proactive measures to prevent falling accidents on work sites. CONCLUSIONS: Preventing falls from movable scaffolds (and height in general) is needed in the construction industry. We propose a fall prevention index based on the working environment (at height, with or without handrail) and experience of workers on movable scaffolds.

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BACKGROUND: Control selection in heavy machinery may be a problem due to the poor compatibility of the commonly-used single line of vertical levers for controls. OBJECTIVE: This study examined the effects of control arrangements on directional compatibility and participant responses in terms of choice/function of controls. METHODS: We investigated experimentally, for a number of new designs of control arrangements, the selection of controls for requested functions of four different machines: fork lift trucks, excavators, tower cranes, and telescopic cranes. Control arrangements were designed with different levels of directional compatibility and participants were requested to nominate which control was related to each of the machine motions and to make ratings of certainty of response. A second part required participants to rank the various control arrangements in terms of their compatibility. RESULTS: The in-line control arrangement was worst for each machine and increased directional compatibility improved the stereotype strength, certainty of response and ranking of control arrangement. CONCLUSIONS: Directional compatibility is the main factor in the design of control/machine output arrangements due to its effect on stereotype strength and correct selection of control of a given function.

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OBJECTIVE: Asbestos was widely used in construction in both a friable and a compact form until the 1990s, before its use was banned. Today, many of these materials are still in situ and represent a source of risk for construction workers. The objective of the study was to analyse the cases of mesothelioma arising among construction workers registered in the Apulia regional register of mesothelioma. RESULTS: For the period 1993-2018, there were 178 male cases, and 10.2% of the cases were present in the regional register. The average age at diagnosis was 64.7 years. The site was pleural in 96.06% of cases, with a diagnosis of certainty in 86.5% of the total cases and 61.8% of cases with epithelial histology. The average latency is 43.9 years. In 75.2% of cases, the exposure began between 1941 and 1970, with an average duration of 24.3 years. The age at the start of exposure in 68.5% of cases is between 8 and 20 years. The ORs were 2.5 (C.I. 95% 1.01-6.17) for the epithelioid histotype and the high duration of exposure. The data underline the need for prevention and information on all activities involving construction workers in which asbestos-containing materials are still used.

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We compared three passive exoskeleton designs in a mock drilling task under three precision requirements levels, defined by required hole sizes, in terms of physical demands (perceived exertion and muscular activation) and quality. The investigated designs were: 1) an upper-body exoskeleton mainly supporting the shoulder; and both 2) full-body, and 3) upper-body exoskeletons, each with connected supernumerary arms. At a fixed pace, participants (n = 12) repeated "drilling" two same-sized holes for 2 min. A fairly consistent result across exoskeleton designs was that higher precision demands increased some muscle activation levels and deteriorated quality. Designs with supernumerary arms led to the largest reductions in quality and increased physical demands overall, mainly in the low back. The shoulder-focused exoskeleton reduced shoulder demands but appeared to reduce quality with the highest precision requirement. Although future work is needed under more diverse/realistic scenarios, these results might be useful to (re)design occupational exoskeletons.

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RATIONALE: Penetrating neck traumas are dangerous and have a high mortality rate, particularly in patients with common carotid artery injuries. Advances in diagnostic imaging technology have shifted management of penetrating neck injuries from mandatory exploration to selective management. The question is now regarding optimal selection of auxiliary examinations to assess "stability" rapidly and guide clinics in managing such patients. PATIENT CONCERNS: A 56-year-old man suffered neck trauma with the right common carotid artery caused by a percussive drill. The carotid artery could not be clearly displayed in computed tomography (CT) angiography imaging. DIAGNOSES: Penetrating neck trauma due to percussive drill bit with common carotid artery injury. INTERVENTIONS: X-ray and bedside duplex ultrasound with color Doppler flow imaging were used to assess the state of trauma and the foreign body was removed under general anesthesia. OUTCOMES: The patient was discharged at postoperative day 10 with no complication. The patient had no sequelae from this injury at 6-month follow up. LESSONS: X-ray provides a comprehensive assessment of damage, and can efficiently detect foreign bodies in the skull and cervical vertebrae. Duplex ultrasound to be a viable method to exclude macrovascular injury in unstable patients who are not eligible for computed tomography angiography (CTA) or catheter angiography imaging. Widely available duplex ultrasound and x-ray should be considered in emergency situations.

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Drilling large holes (e.g., 10-20 mm diameter) into concrete for structural upgrades to buildings, highways, bridges, and airport runways can produce concentrations of respirable silica dust well above the ACGIH® Threshold Limit Value (TLV® = 0.025 mg/m3). The aim of this study was to evaluate a new method of local exhaust ventilation, hollow bit dust extraction, and compare it to a standard shroud local exhaust ventilation and to no local exhaust ventilation. A test bench system was used to drill 19 mm diameter x 100 mm depth holes every minute for one hour under three test conditions: no local exhaust ventilation, shroud local exhaust ventilation, and hollow bit local exhaust ventilation. There were two trials for each condition. Respirable dust sampling equipment was placed on a "sampling" mannequin fixed behind the drill and analysis followed ISO and NIOSH methods. Without local exhaust ventilation, mean respirable dust concentration was 3.32 (± 0.65) mg/m3 with a quartz concentration of 16.8% by weight and respirable quartz dust concentration was 0.55 (± 0.05) mg/m3; 22 times the ACGIH TLV. For both LEV conditions, respirable dust concentrations were below the limits of detection. Applying the 16.8% quartz value, respirable quartz concentrations for both local exhaust ventilation conditions were below 0.007 mg/m3. There was no difference in respirable quartz dust concentrations between the hollow bit and the shroud local exhaust ventilation systems; both were below the limits of detection and well below the ACGIH TLV. Contractors should consider using either local exhaust ventilation method for controlling respirable silica dust while drilling into concrete.

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OBJECTIVE: The aim of this study was to evaluate the ergonomic benefits of an angle grinder with a rotatable main handle in a cutting task. BACKGROUND: Angle grinder manufacturers rarely address ergonomic features in their advertisements, and if they do, the benefits are expressed in a qualitative manner. Meanwhile, quantitative information about the effects of the device on the worker is required to make informed decisions during tool selection and cumulative trauma prevention. METHOD: Eleven maintenance workers and metalworkers used an angle grinder to cut a horizontal steel rod using three wrist postures. Only one of the postures was exclusively available in the case of a rotatable main handle. The postural effect was evaluated objectively with electromyography and a force-sensing-resistor-based force glove. Subjective ratings about discomfort and control were obtained with a visual analog scale. RESULTS: The subjective ratings favor the near-neutral wrist posture. The forearm muscles' electromyographic activities were similar across the postures. Forces on the hand-handle interface were concentrated on the intermediate phalanges. If the device is operated without gloves, the forces on the intermediate phalanges may exceed the discomfort pressure threshold regardless of wrist posture. CONCLUSION: In the cutting task, the subjective measures favor the posture with a near-neutral wrist, which is a feature of the rotatable main handle. The objective measures did not allow one to prefer one posture to another. APPLICATION: The findings give insight into the impact of wrist posture on muscle activity, forces on the hand-handle interface, and discomfort. This is useful information for the person responsible for tool selection.

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OBJECTIVES: Both pneumatic rock drills and electric rotary hammer drills are used for drilling large holes (e.g., 10-20 mm diameter) into concrete for structural upgrades to buildings, highways, bridges, and airport tarmacs. However, little is known about the differences in productivity, and exposures to noise, handle vibration, and dust between the two types of drills. The aim of this study was to compare these outcomes with similar mass electric rotary and pneumatic rock drills drilling into concrete block on a test bench system. METHOD: Three experiments were conducted on a test bench system to compare an electric (8.3 kg) and pneumatic drill (8.6 kg) on (1) noise and handle vibration, (2) respirable silica dust, and (3) drilling productivity. The test bench system repeatedly drilled 19 mm diameter x 100 mm depth holes into cured concrete block while the respective exposure levels were measured following ISO standards. RESULTS: Productivity levels were similar between the electric and the pneumatic drill (9.09 mm/s vs. 8.69 mm/s ROP; p = 0.15). However, peak noise (LPeak: 117.7 vs. 139.4 dBC; p = 0.001), weighted total handle vibration (ahw: 7.15 vs. 39.14 m/s2; p = 0.002), and respirable silica dust levels (0.55 vs. 22.23 mg/m3; p = 0.003) were significantly lower for the electric than the pneumatic drill. DISCUSSION: While there were no differences in drilling productivity between an electric and pneumatic drill of similar mass, there were substantial differences in exposure levels of noise, handle vibration, and respirable silica dust. Structural contractors should switch from pneumatic rock drills to electric rotary hammer drills for structural drilling into concrete in order to reduce worker exposures to the hazards of noise, hand vibration, and silica dust.

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We compared different passive exoskeletal designs in terms of physical demands (maximum acceptable frequency = MAF, perceived discomfort, and muscular loading) and quality in a simulated overhead drilling task, and the moderating influence of tool mass (∼2 and ∼5 kg). Three distinct designs were used: full-body and upper-body exoskeletons with attached mechanical arms; and an upper-body exoskeleton providing primarily shoulder support. Participants (n = 16, gender-balanced) simulated drilling for 15 min to determine their MAF, then maintained this pace for three additional minutes while the remaining outcome measures were obtained. The full-body/upper-body devices led to the lowest/highest MAF for females and the lowest quality. The shoulder support design reduced peak shoulder muscle loading but did not significantly affect either quality or MAF. Differences between exoskeleton designs were largely consistent across the two tool masses. These results may be helpful to (re)design exoskeletons to help reduce injury risk and improve performance.

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A prediction model is used to predict subjective responses of crane operators with respect to different designs of In-Vehicle Visual Support (IVVS). Selected gaze metrics are used as objective metrics to minimize prejudice, which is commonly caused by subjective measures. Experiments are carried out using crane simulator to measure glance behavior of novice operators and the 3D perspective projection method is used for autonomous mapping of gaze fixations to dynamic Area-of-Interests (AOIs). Subjective responses, such as operators' emotion and usability of IVVS, are evaluated using the Likert scale of the Semantic Differential method. Correlation between gaze metrics and subjective responses is established using multiple linear regression. Glance behavior exhibits a statistically significant difference when information on IVVS is perceived as useful to ease operation and reduce tension. Despite this, there are no significant signs of distraction. Glance behavior is found to be a reliable sub-conscious indicator of subjective response and distraction. More importantly, the proposed gaze metrics are found to be a good representation of glance behavior, such as randomness and distribution of attention. The methods and findings are useful to evaluate impact of IVVS, which is becoming more common in many other applications.

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In February 2012, a serious accident which resulted in five fatalities happened during a TBM-tunnel construction under the seabed in Japan. The cause of the accident appeared to be due to the Key-segment slipping out of the segment ring by the thrusting tailskin (wire brushes) of the TBM into the segment ring. This resulted in the collapse of the rings, causing the seabed ground and seawater to flow into the tunnel. We investigated how thin and thick segments without any circumferential joints behave under isotropic and anisotropic pressures using small-scale physical model. In the model tests, pressures were applied to the surroundings of the segment rings and the strains at each segment were measured in order to evaluate the damage. In addition, cases where lubrication on the contact area between the K- and B-segments was present or not were investigated and their discrete element simulations were also conducted.

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The portable high-efficiency air filtration (PHEAF) device is used to control particulate matter (PM) generated from construction-type activities occurring within the built environment. Examples of activities where PHEAF devices are mobilized include building renovation, asbestos abatement, remediation of microbial contamination, and lead-based paint projects. Designed for use on short-term, temporary projects the PHEAF device captures airborne PM using a high-efficiency particulate air (HEPA) filter. This study sought to evaluate the capture efficiency of the PHEAF device in a field setting. An aerosol generator and photometer were used to measure particle penetration through 85 PHEAF devices. Average overall capture efficiency ranged from 41.78% to ≥99.97% with more than 88% of the tests failing to achieve 99.97% capture efficiency. Approximately 73% of the PHEAF device sample population failed to demonstrate HEPA performance criteria during any test round. A higher occurrence of PM concentrations measured around the perimeter of the filter suggested the presence of bypass leakage. While PHEAF devices were effective in capturing a significant quantity of aerosol test agent, these findings suggest that routine testing of the PHEAF device should be conducted to validate performance.

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