Development and evaluation of head load manager for construction workers

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Date
2020-08
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CCSHAU, Hisar
Abstract
Women construction workers at construction sites are primarily involved in various unskilled tasks like cleaning building sites, carrying bricks, gravel, mortar and water up to the skilled masons. The present study was conducted on women workers at construction sites to indicate work complexity in actual field conditions and ergonomic assessment of existing ergo solutions to address their issues related to musculoskeletal disorders. In Phase I, work profile of 30 women workers of 20-40 years of age engaged in head load carrying activity was evaluated and their ergonomic assessment done by providing them with existing ergo solutions, viz. HLM, HLC, HLH. In Phase II, the problems reported in Phase I were utilized for designing and development of Head Load Manager with the help of simulating software ANSYS. In Phase III, ergonomic assessment of 30 women workers was done by providing them the modified Developed Head Load Manager. In Phase IV, feasibility testing of the Developed Head Load Manager was done with the help of modified Rogers and Shoemaker Scale and User Assessment Sheet. The study revealed that majority of the respondents were in the age group of 30-40 years (66.67%), married (63.33%), illiterate (60%), belonged to nuclear family (70%), and hailed from West Bengal (30%). Majority of the respondents (60%) were employed on daily basis. More than half of the respondents (60%) received wages in between 250-350, and 50% were getting their wages on daily basis. The WHR (120.14b/min) of the respondents before activity was significantly lesser than that observed with Conventional Method (137.67 b/min), HLC (132.80b/min), HLM (134.86b/min) and HLH (133.77b/min). On the other hand, RHR (107.51b/min) was also significantly lesser in comparison to the other methods with respect to grip strength of right hand. In Phase II, Stainless steel, Gray cast iron, and Aluminium alloy were compared to obtain a low cost, durable and lightweight product. A 3D model was created with the help of ZWCAD software and their strengths were compared with the help of ANSYS by applying a force of 98N, 196N, 294N, and 392N. All of them had an acceptable level of deformation and von Mises stress. Gray cast iron material was preferred in making the final product, as it was cheaper than stainless steel and Aluminium alloy. The product was modified to decrease the discomfort while carrying bulky load on head and was designated as Developed Head Load Manager (DHLM). During Phase III, ergonomic assessment was done on 30 respondents and a highly significant decrease was observed in WHR (12.79b/min), RHR (10.84b/min) and EER (2.03kJ/min). Oxygen consumption rate also decreased up to 23.25 percent with DHLM. TCCW and PCW decreased by 821.55 beats, 13.69 b/min while using DHLM. Grip strength of right hand (14.61%) as well as left hand (17.68%) were reduced after performing the activity with DHLM. There was a significant reduction in the discomfort at head, neck, shoulders, upper back, upper arms, mid- back, chest, lower arms, wrists, lower back, buttocks, thighs, knee, legs, and feet. On the basis of various attributes i.e. relative advantage, compatibility, simplicity/complexity and practicability, practicability got the first rank (2.31) followed by relative advantage (2.15), while compatibility and simplicity/complexity got the third rank (2.07) each. The DHLM was acceptable to the women workers as it was found easy to handle, reduced their physiological and biomechanical stress and contributed to reduce their overall discomfort while carrying heavy load on the head. The findings of the study shall be helpful for the manufacturers and product designers to develop a prototype DHLM on mass scale for the benefit of workers engaged in construction industry, thereby mitigating the incidence of occupational hazards.
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