Final phase of the project

CRITICAL ANALYSIS OF MUSCULOSKELETAL DISORDERS IN CONSTRUCTION WORKERS

Submitted to Dept. of Industrial Engineering & Management [May 2016]

Bachelor of Engineering

In

Industrial Engineering & Management

By

MANASA UPADHYA [1BM12IM028]

THAMAR MOIDEEN [1BM12IM059]

SAI SHARAN [1BM12IM047]

NITHIN SURESH [1BM12IM035]

Under the Guidance of

Smt. V.N. SHAILAJA

DEPARTMENT OF INDUSTRIAL ENGINEERING & MANAGEMENT

B.M.S COLLEGE OF ENGINEERING BENGALURU 560019

Page | 1

CERTIFICATE

Department of Industrial Engineering and Management B.M.S College of Engineering, Autonomous College under VTU

BANGALORE 560019

This is to certify that this Bachelor of Engineering Project Report titled “CRITICAL ANALYSIS OF MUSCULOSKELETAL DISORDERS IN

CONSTRUCTION WORKERS”By:

THAMAR MOIDEEN 1BM12IM059SAI SHARAN 1BM12IM047

NITHIN SURESH 1BM12IM035MANASA UPADHYA 1BM12IM028

as part of the 8th semester curriculum in Bachelor of Engineering in Industrial Engineering and Management , B.M.S College of Engineering during the year

2015-2016Guide:

Smt. V.N. SHAILAJAAssistant Professor

Department of Industrial Engineering and ManagementBMS College of Engineering, Bangalore- 19

Dr. K.J. RATHAN RAJProfessor and Head Dept. of Industrial Engineering and Management, BMSCE

Dr. K. MALLIKHARJUNA BABU Principal BMS College of Engineering

Name of the Examiner Signature with Date

1

2

Page | 2

ACKNOWLEDGEMNT

We express our sincere gratitude and respect to Dr. K.J Rathanraj, HOD of IEM,

BMSCE, for approving and letting us carry out this report.

We would also like to thank our internal guide, Mrs. V.N. Shailaja, faculty of IEM,

BMSCE, for providing us with constant support and guidance during the length of this

project.

Also we’d like to be grateful to Dr. B. Ravishankar, faculty of IEM,BMSCE, for

helping us and taking us step by step through this project.

Page | 3

ABSTRACT

The project is titled, “Critical Analysis of Musculoskeletal Disorders in Workers

of Construction Industry”.

The objective of this project is to use the tools of statistics with parameters in

relevance of musculoskeletal disorders. Thereafter, prove the existence of MSD’s.

The techniques used to gather information is through a survey to obtain a sample size

large enough to apply methods of hypothesis.

The survey will contain a questionnaire judging the socio-economic conditions, job

descriptions, physical and mental health conditions of construction workers. A point

scale of 0-5 is used to mark the distinction.

The strain index is found using the Moore-Garg model to find the mean standard

deviation of the worker with & without MSD’s, and the total sample.

The hypothesis tests involved uses the knowledge of Statistics such as the P test to

determine the population percentage of worker having the musculoskeletal disorders.

The identified results thus obtained are used to find the solutions at varying degree

with the backbone of Ergonomics.

Page | 4

CONTENTS

Sl No. PARTICULARS Page No.

ACKNOWLEDGEMENT 3

ABSTRACT 4

LIST OF FIGURES AND TABLES 6

1. INTRODUCTION 7

2. COMPANY PROFILE 8

3. PROBLEM DEFINITION 9

4. LITERATURE REVIEW 10

5. METHODOLOGY 26

5.1 SELECTION OF CONSTRUCTION SITE 27

5.2 SAMPLE SIZE CALCULATOR 28

5.3 DATA COLLECTION 30

5.31 NORDIC QUESTIONNAIRE 31

5.32 INPUT FOR NORDIC QUESTIONNAIRE 33

5.33 RULA 34

5.34 MOORE GARG STRAIN INDEX 35

5.35 INPUT ANALYSIS OF STRAIN INDEX SCORE 36

5.4 DATA ANALYSIS 39

5.41 QUALITATIVE ANALYSIS – RELIABILTY AND VALIDITY

TESTS

39

5.42 SPSS STATISTICS 39

5.43 RELIABILITY AND VALIDITY OF THE QUESTIONNAIRE 41

5.44 CRONBACH’S ALPHA 42

5.45 FACTOR ANALYSIS 44

5.46 HYPOTHESIS TEST 46

6. CONCLUSON 49

7. FUTURE SCOPE OF THE PROJECT 50

8. REFERENCES 54

LIST OF FIGURES AND TABLES

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1. Table 2 - Workers Profile2. Figure 4.1 - Decrease in productivity in construction workers in various

industries.3. Figure 4.2 - Depiction of MSDs affecting the human body.4. Table 4.2 - Risk factors involved in MSDs5. Figure 4.31 - Private sector industries affected by MSDs6. Figure 4.32 - MSDs the leading construction injury7. Figure 4.41 - Depiction of Carpel Tunnel Syndrome8. Figure 4.42a - Depiction of Ankle with Tendonitis9. Figure 4.42b - Depiction of Elbow with Tendonitis10. Figure 4.43 - Depiction of Raynaud’s Syndrome11. Figure 4.44 - Depiction of Thoracic Outlet Syndrome12. Figure 4.51 - Various body parts affected by MSDs in carpenters13. Figure 4.52 - Various body parts affected by MSDs in plasterers14. Figure 4.53 - Various body parts affected by MSDs in masons15. Figure 4.54 - Various body parts affected by MSDs bricklayers16. Figure 4.72 - Ergonomic Program Elements17. Figure 4.73 - Ergonomic Solutions18. Figure 4.74a - Lying of cement made easier19. Figure 4.74b - Rebar tying manually20. Figure 4.74c - Rebar tying with equipment21. Figure 4.74d - Manual handling of drilling machine22. Figure 4.74e - drilling with equipment23. Figure 4.74f - Personal protection equipment guidelines24. Model 5.1 - Flow chart of MSD MODEL25. Figure 5.1 - Construction site at Anandamachani Residential site26. Figure 5.2 - Sample size calculator27. Figure 5.21 - Population size at the site28. Figure 5.3a - Collection of answers to Nordic Questionnaire29. Figure 5.3b -Assessment of worker’s movement30. Figure 5.31 - Sample of the Nordic questionnaire31. Figure 5.33 - Sample of the Rula scale32. Figure 5.34 - Sample of the Moore-Garg index33. Table 5.35 - Input to SI34. Figure 5.36 - Demographics35. Figure 5.46 - Selection of statistical tests36. Figure 5.47 - Normal Distribution curve regarding Z-score37. Model 7. -Muscle fatigue analysis38. Figure 7.1 - Model of 3DSSP39. Figure 7.2 - Modeling the mannequin to the proposed display along with

the input values to the posture angles and the load carried40. Figure 7.3 - Report summary about various regions of the body

1. INTRODUCTION

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OSHA defines musculoskeletal disorders as “Injuries and disorders of the muscles,

nerves, tendons, ligaments, joints, cartilage, and spinal disk”. According to OSHA,

the MSDs listed as: Carpel tunnel, Rotator cuff syndrome, De Quervain, Trigger

finder, tarsal syndrome, Sciatica, Epicondylites, and Tendonitis.

Most of the work related MSD’s are developed over time and are caused by the work

itself or the working environment of the employees. These are also possible to occur

from accidents, examples being fractures and dislocations.

Musculoskeletal disorders primarily affects the back, neck, shoulders and upper limbs

, less often they affect the lower limbs .Health problems caused by MSD’s range from

discomfort , minor aches and pains , to more serious medical conditions requiring

time off work and even medical treatment . In some chronic cases the result could be

permanent disability and loss of employment. Examples of specific MSD disorders

are carpel tunnel syndrome, epicondylitis and tendinitis.

Every year millions of workers are affected by MSDs. Some of the well-known MSDs

are low back pain and work-related upper limb disorders. The first is mainly

associated with manual handling while the main risk factors for the latter are

associated with job repetition and awkward work posturing.

Work related MSD’s with repetitive and strenuous working conditions carry on to

represent one of the biggest occupational problems in industries. Despite the variety

of efforts to control them, including engineering design changes, organizational

modifications and introducing working methods training programs, work-related

musculoskeletal disorders account for a huge amount of human suffering and to

companies and to healthcare firms.

Work-related musculoskeletal disorders have claimed to be one of the major problems

in many industrialized and developing countries. These disorders are widely known in

many countries, with substantial costs and impacts on the workers quality of life.

They also constitute a major proportion of all registered and/or compensation-eligible,

work-related diseases in many countries. Hence, there is a dire need to address this

issue with studies and surveys and present a model that will mitigate the problem in

the future.

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2. COMPANY PROFILE

Simplex Infrastructures Ltd. is a diversified company established in 1924 and executing projects in several sectors like Transport, Energy & Power, Mining, Buildings, Marine, and Real Estate.

Simplex is one of the construction leaders in India for nearly 90 years executing projects with consistent quality assurance, cost control and adherence to milestones in a safe environment as per the customer requirements at large.

The Company is engaged in the design and construction of high-rise infrastructure, comprising - multi-storeyed residential towers, institutional/IT Buildings, hotels, hospitals and mass housing projects. Simplex undertook cumulative construction projects across 20mn sq. ft. for some of the biggest developers in India. At the construction site in Chamrajpet, Bangalore-18, details of the construction area is depicted as follows: SL DESCRIPTION DETAILS ON

JAN AND FEBCUMULATIVE SINCE BEGINING

1 AVERAGE MAN POWER 379 4018.94

2 TOTAL MAN HOURS WORKED 117598 1263994

3 TOTAL SAFE MAN HOURS ACHIEVED

117548 1263499

4 MAN DAYS OST DUE TO REPORTABLE ACCIDENTS

NIL NIL

5 NO OF PERSONAL INDUCTED 71 1461

6 NO OF TOOLBOX TALK CONDUCTED

20 5235

7 NO OF SAFETY TRAINING 01 19

8 NO OF FIRST AID CASES 07 84

9 NO OF REPORTABLE ACCIDENTS NIL NIL

Table 2 – Worker’s profileThe site consists of two sections which are to be constructed up to 18 floors each with 4 levels of underground parking as well. One section has been built up to the 15th floor and the other section is still at the parking level.

The site has an average man power of 300 workers over a period of a month and we conducted a survey between the age group of 20-55 years which consists of fitters, carpenters, masons, and plasterers all together made up to 255 workers which is used as our total population size.

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3. PROBLEM DEFINITION

WMSD’s are an impairment and disability among construction workers. An improved

understanding of MSD’s in different construction workers is likely to give us

preventive measures. However, the construction industry is vast in its division of

labour and the assessment of which is difficult in a short period. Hence, we intend to

focus on workers with problems concerning the upper body movements i.e., using

hand tools.

The following workers are concentrated on; sheet metal workers, painters, carpenters

and masons. Most of their injuries are strains and sprains of the upper body muscles.

The population size of the construction site is too large to take in consideration and

hence there is a need to find the sample size. The survey will contain a questionnaire

of Nordic scheme that judges the socio-economic conditions, job descriptions,

physical and mental health conditions of construction workers with the help of Likert

scale is used to rate the pain associated with MSD.

The questionnaire requires a field of narrowed down workers whose job concerns

with the upper body movements. The analysis of the work is not a onetime process

and requires regular visits involving repeated surveys. The Repeatability in the

questionnaire is necessary to obtain consistent results to reduce the error and to

identify the prevalence of MSD’s.

We need to assign a standard value for all the workers equally and hence there is a

need to find the strain index. In order to prove the existence of MSD’s among the

construction workers, certain statistical tools are in need and also to categorize the

MSD workers from the non-MSD workers.

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4. LITERATURE REIVEW

4.1 Work relatedness of Musculoskeletal Disorders

Historical records and other documentations show the relevance of musculoskeletal

disorders, and their association with occupations was recorded long before the

introduction of sickness benefit schemes and compensation claims were evident. All

previous studies conducted show the pre-existing social conditions have tremendous

effect on the health of individuals and communities.

Musculoskeletal disorders are mostly characterised as “work related disorders” than

calling them “occupational disorders”. The latter is defined one which has a direct

cause and effect relationship on the hazard and the disease. Whereas a work related

disorder is multifactorial which has the work environment and the performance of

work contribute significantly.

Certain epidemiologic studies reveal that the “work related” musculoskeletal

disorders is seen in more than one occupation. The common trait of these happens to

be the intensive and repetitive use of hands.

0

20

40

60

80

100

120

no sick leave Atleast one day ofsick leave but less than a monthAtleast one month sick leave

per

cent

age

of w

orke

rs

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Figure 4.1– Decrease in productivity among workers in various industries

4.2 MSD Risk Factors:

Force

Repetition

Awkward postures

Static Postures

Quick Motions

Compression or Contact Stress

Vibration

Figure 4.2 – Depiction of musculoskeletal disorders affecting the human body

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Factors Possible result or

consequence

Example Good practice example or

solution

Exertion of high-

intensity forces

Acute overloading of

tissues

Lifting,carrying,

pushing, pulling,

Avoid manual handling of

heavy objects

Handling heavy loads

over long periods of

time

Degenerative diseases

especially of the lumbar

spine

Manual materials

handling

Reduce mass of objects or

number of handlings per

day

Frequently repeated

manipulation of

objects

Fatigue and over load of

muscular structures

Assembly work,

long time typing,

check out work

Reduce repetition

frequency

Working in

unfavorable posture

Overload of skeletal and

muscular elements

Working with

heavily bent or

twisted trunk or

hands and arms

above shoulder

Working with upright trunk

and the arms close to the

body

Static muscular load Long lasting muscular

activity and possible

overload

Working overhead,

working in confined

space

Repeated change between

activation and relaxation of

muscles

Muscular inactivity Loss of functional

capacity of muscles,

tendons and bones

Long term sitting

with low muscular

demand

Repeated standing up,

stretching of muscles,

sports activities

Monotonous

repetitive

manipulations

Unspecific complaints in

the upper extremities(RSI)

Repeated activation

of the same muscles

without relaxation

Repeated interruption of

activity and pauses

alternating tasks

Application of

vibration

Dysfunction of nerves,

reduced blood flow,

degenerative disorders

Use of vibrating

hand tools, sitting on

vibrating vehicles

Use of vibration attenuating

tools and seats

Physical

environmental

factors

Interaction with

mechanical loads and

aggravation of risks

Use of hand held

tools at low

temperatures

Use of gloves and heated

tool at low temperatures

Psychosocial factors Augmentation of physical

strain, increase in absence

from work

High time pressure,

low job decision

latitude, low social

support

Job rotation, job

enrichment, reduction of

negative social factors

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Table 4.2– Risk factor involved in MSDs

4.3 MSDs: THE LEADING CONCERN IN PRIVATE SECTOR INDUSTRIES

This indicator is used to measure the number of individuals reported by the employers

to have the missed days of work due to a musculoskeletal disorder. Musculoskeletal

disorders include carpal tunnel syndrome, injury to the neck and shoulders, or any

injury to the back.

Among the various other industries we can see that musculoskeletal disorder rates for

construction industry are among the top three. Musculoskeletal disorders usually

develop due to overuse of muscles, some of the bad postures, or repeated movement;

Work-related musculoskeletal disorders are possible to be prevented. With the correct

controls and efficient ergonomic design in the respective work places.

The graph shown below gives us a detail information about the occurance of

musculoskeletal disorders among various industries and its evident that the

construction industry has prominent occurance of musculoskeletal disorders .

Goods production

Construction

Service providing

Healthcare and social assistance

0 10 20 30 40 50 60 70 80 90

Musculoskeletal disorder incidence rates for selected private sector industries, 2014-2015

2015 2014Source: U.S. Bureau of Labor Statistics

Incidence rate per 10,000 full-time workers

Figure4.31 – Private sector industries affected by MSDs

Page | 13

Neoplasms8%

M[][]

Ner-vous Dis-

order3%

Circu-latory Res-pira-tory Dis-

order18%

Res-pira-tory Dis-

order4%

Di-ges-tive Dis-

order2%

Mus-cu-

loskeletal Dis-

order44%

Injury and Poi-son-ing4%

Other10%

Occupational diseases in Construction inDustries

Figure 4.32 - MSD’s: The Leading Construction Injury

4.4 Main Types of Musculoskeletal Disorders

4.41 Carpel Tunnel Syndrome

One of the most commonly occurring disorder among the construction workers is the

Carpel Tunnel Syndrome. The definition of which goes as such, the pain, numbness

and the tingling sensation at the wrists and the arms that could also affect the

shoulders in time. The pinch of nerves at the wrists is the cause of this disorder.  The

carpal tunnel is a narrow passageway located on the palm side of your wrist, bound by

bones and ligaments. This tunnel protects the main nerve to your hand and the nine

tendons that bend your fingers.

Figure 4.41 Depiction of Carpel T1unnel Syndrome

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4.42 Tendonitis

Traditionally, tendonitis is the tendon injury caused by the repetitive use of

mechanical loads and the subsequent inflammatory response. This type of injury can

occur at the wrists, elbows, shoulders, knees and ankles. Tools with hard edges or

ridged handles, and the repeated bending of the fingers while trying to maintain a

forceful grip can cause this deformation in construction workers.

Figure 4.42(a) Ankle showing Tendonitis

Figure 4.42(b) - Elbow showing Tendonitis

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4.43 Raynaud’s Syndrome

Raynaud’s Syndrome is often caused by the use of vibrating hand tools such as power

hand tools, grinding wheels, chain saws, jackhammers, wrenches, and impact tools.

The disorder is the result of damage to the nerves and blood vessels in the hands and

causes numbness and weakness in the hands and fingers. Raynaud’s Syndrome can

also cause a whitening of the fingers, hand, and sometimes the forearm to the elbow.

Fig 4.43: Restricted blood flow due to Raynaud’s syndrome

4.44 Thoracic Outlet Syndrome

It is a disorder of the shoulder that occurs when work is done overhead or heavy items

are carried in the hands with the arms extended straight down causing reduced blood

flow. Construction workers who are at risk of this disorder include welders, painters,

and insulators.

Figure 4.44: Compression of arteries, veins and nerves

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4.5 Major WMSDs affecting the different construction workers

4.51 Carpenters

Workers in this group report musculoskeletal symptoms of the back, neck/shoulders, hands/

wrists and knees. Working overhead or at/above shoulder level is an essential component of

electrical work and it is a risk factor for shoulder injury. Additional risk factors for shoulder

injuries are inadequate rest, static loads, vibration and awkward postures.

Neck Shoulder Upper Back

Elbow Hands Lower Back

Legs Knees Ankle0

10203040506070

% of workers affected

Figure-4.51 Various Body Parts affected by MSDs in Carpenters

4.52 Plasterers

The body parts most commonly injured are the axial skeleton and shoulder, where

back sprains, simultaneous sprains to the back and neck, and shoulder strains occur

frequently must often stand for long periods and manually lift heavy raw materials

and finished goods.

Neck Shoulder Upper Back

Elbow Hands Lower Back

Legs Knees Ankle0

10

20

30

40

50

60

% of workers affected

Figure 4.52- Various Body Parts affected by MSDs in Plasteres

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4.53 Masons

Masons must manually lift heavy raw materials and finished pieces. This work

requires bending, lifting, standing, climbing or squatting, sometimes in close quarters

or awkward positions Common ergonomic-related risk factors may include awkward

body positions that strain the arms and back.Manually lifting heavy materials, such as

manipulating concrete, mortar or terrazzo mixtures, can also cause low-back

injuryCement masons and terrazzo workers may suffer chemical burns from uncured

concrete and may experience sore knees from frequent kneeling and crouching.

Neck Shoulder Upper Back Elbow Hands Lower Back Legs Knees Ankle0

10

20

30

40

50

60

% of workers affected

Figure4.53- Various Body Parts affected by MSDs in Masons

4.54 Bricklayers

Common MSD’s situated with roofers involve the backs holders, hands/fingers, knees

and feet/ankles. Roofers conduct strenuous physical, manual work that involves heavy

liftings, climbing, bending and kneeling.

Neck Shoulder Upper Back

Elbow Hands Lower Back

Legs Knees Ankle0

10

20

30

40

50

60

% of Workers affected

Figure 4.54-Various Body Parts affected by MSDs in Brick Layers

Page | 18

4.6 Development of Ergonomics

Ergonomics is a term that has been defined and used for the past 50 years. There also

happens to be a documentation of it being recorded pre-historically. Early man was

known for making fashioned tools, scoops from bones and utensils, generally

implying that there was a constant and a meticulous interaction between human and

the environment. Hippocrates, the father of medicine prescribes how a surgeon must

stand or sit while operating, how he must handle his gauges and tools, to avoid glare

of light and the shape, size, weight and composition of the tools used. Slaves in

ancient Greek were given guidelines of working in mines and construction sites.

In more modern times, the 20th century had Taylor defining the scientific study of

work. Now, more than ever, it has become a widespread discipline no longer

concerning just men and work. The IEA defines it as, “concerned with the

understanding of the interactions among humans and other elements of a system, and

the profession that applies theoretical principles, data and methods to design in order

to optimise human well-being and overall system performance”. The IEA being the

International Ergonomics Association is a federation of ergonomics and human factor

societies around the world. It was initially concerned with the welfare and the

productivity of the workers but the change of time has called for it to concern itself

with the non-work activites and mental health of workers. Countries all over the

world, majorly being Australia, Germany, Brazil, South Africa and the USA have had

colossal developments in the recent years.

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4.7 ERGONOMICS IN REDUCTION AND PREVENTION OF MSDs

Ergonomics is important because when you’re doing a job and your body is stressed

by an awkward posture, extreme temperature, or repeated movement which affects the

musculoskeletal system. The body may begin to have symptoms such as fatigue,

discomfort, and pain, which can be the first signs of a musculoskeletal disorder.

4.71 Advantages of ergonomics

1. Increased savings

2. Fewer injuries

3. More productive and sustainable employees

4. Fewer workers’ compensation

5. Increased productivity

6. Increased morale

7. Reduced absenteeism

8. Implementing ergonomic improvements can reduce the risk factors that lead to

discomfort.

4.72 Ergonomic Elements

Recognition and Identification of Work Related MSD Problems

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Ergonomics Program Elements

Recognition and Identification of

Work Related MSD Problems

Worksite Evaluations

Employee Involvement

and Participation Implementation

of Hazard Controls

Training and Education

This analysis is conducted with the help of methods to determine static postures and its corresponding ratings in order to identify the various problem areas that arise with in the construction workers. The presence of MSDs was obtained using statistical tools from the data obtained from these methods.

Worksite EvaluationsThe evaluation of the construction worker was done with the help of questionnaire methodologies and direct observation. The positive responses on these tests for the particular part of the body along with the recurring or prolonged discomfort in the same area was defined as WMSDS. The direct observation is used to gauge Intensity of exertion, duration of effort, hand/ wrist postures, speed of work and duration of tasks.

Employee Involvement and ParticipationThere are various categories of construction workers involved at the construction industry such as masons, carpenters, plumbers, electricians, plasterers etc.

Implementation of Hazard Controls• Breaking each specific job down into elements.• Identifying conditions within a job that contribute to risk.

Training and EducationThere are four aspects of ergonomic training that can be provided.

• General ergonomics awareness information – All employees• Formal awareness instruction and job-specific training – Employees involved

in job tasks• Training in job analysis and controlling risk factors – Risk assessment

employees and ergonomic team members• Training in Problem solving and the team approach – Ergonomic team

members.

4.73 Ergonomic Solutions

• Ergonomic hazards are prevented primarily by the effective design of a job or

job-site and the tools or equipment used in that job

• Based on information gathered in the work-site analysis, procedures can be

established to correct or control ergonomic hazards using either engineering

controls or work practice controls

Page | 21

• Thoughtful arrangements reduce stress and eliminate many potential injuries

and disorders associated with the overuse of muscles, with bad posture, and

with repetitive motion

Some jobs expose workers to excessive vibration and noise, eyestrain, repetitive

motion, and heavy lifting

Machines, tools, and the work environment may be poorly designed, placing stress on

workers' tendons, muscles, and nerves and in addition, workplace temperature

extremes may aggravate or increase stress

Equiment o

r Engineerin

g

Job Organiza

tion

Personal P

rotective

equipement

Body Mech

anics

Ergonomic Solution

Effectiveness Personal Control

wor

lers

ben

efite

d

`

Figure 4.73 Ergonomic Solutions

4.74 Hazard Prevention and Control

OSHA describes the various ways the elimination and the prevention of the hazards that could be affecting the construction industry. The approach to this is obtained through :

Engineering Controls Administrative Controls Personal Protective Equipment

1. Engineering ControlsThe first and best strategy is to control the hazard at its source. Engineering controls do this, unlike other controls that generally focus on the employee exposed to the hazard. Engineering controls can be simple in some cases. They are based on the following principles:

Page | 22

If feasible, design the facility, equipment, or process to remove the hazard or substitute something that is not hazardous.

If removal is not feasible, enclose the hazard to prevent exposure in normal operations.

Where complete enclosure is not feasible, establish barriers or local ventilation to reduce exposure to the hazard in normal operations.

Figure 4.74 a - Lying of cement made easier

Figure 4.74 b– Rebar tying manually Figure 4.74 c- Rebar tying with equipment

Page | 23

Figure 4.74d- Manual handling of drill Figure4.74 e-Drilling with equipment

2. Administrative Controls

This involves no such physical changes to be made to the environment around along with setting limits to the daily exposure to hazards by adjusting the tasks to the schedules. Administration should also provide with written operating procedures, work practises and rules for employees of safety and health.

Other methods that can be implemented through administration controls are:

– Alarms, signs and warnings– Buddy system– Training– Stretching exercises and break policies

Page | 24

3. Personal Protection Equipment

• Used when hazards cannot be eliminated through engineering or administrative controls,

• Must consider personal protective equipment (PPE) necessary for employee protection.

Figure 4.74 f – The Personal Protection Equipment guidelines

Page | 25

5. METHODOLOGY

Page | 26

START

Data CollectedFinding Confidence

Interval

Nordic Questionnaire

Calculating the Sample size(n)

Conducting the Survey

Moore Garg SI

Reliability and validity tests

If valid

*T - TEST

If null hypothesis

Suggest physical model

Y

N

YN

Model 5.1- Flowchart of MSD MODEL

5.1 Selection of the construction site

A four round visit was conducted at the construction site at Simplex Infrastructure

Limited, Ananda Machani Residential Project situated at Chamrajpet to obtain data

pertaining to the number of workers with MSDs. The site consists of two sections which

are to be constructed up to 18 floors each with 4 levels of underground parking as well.

One section has been built up to the 15 th floor and the other section is still at the parking

level.

Figure 5.1 – Construction site at Ananda Machani Residential Project

The site has an average man power of 300 workers over a period of a month and we

conducted a survey between the age group of 20-55 years which consists of fitters, carpenters,

masons, and plasterers all together made up to 255 workers which is used as our total

population size.

Page | 27

STOP

5.2 Sample Size Calculations

We use a sample size calculator to determine how many people are needed to

interview in order to get results that reflect the target population as precisely as

needed.

This calculator uses the following formula

Figure 5.2- Sample size calculator

Page | 28

By taking the total population as 255 and confidence interval as 15 gives us the

needed sample size of 37. In this study we undertake a sample size of 40.

Masons Fitters Plasteres Carpenters0

20

40

60

80

100

120

140

160

148

33 35 3926

5 4 5

Total Population Sample size used

Figure 5.21 - Population Size at the site

Masons (58%), Fitters (13%), Plasterers (13.7%) and Carpenters (15.3%) where taken

into account in this study. We use a scheme of Nordic questionnaire to survey the

participants as questionnaires have proved to be the best means of collecting the

necessary data.

Page | 29

5.3 DATA COLLECTION

Figure 5.3(a) - Collection of answers to the Nordic Questionnaire

Page | 30

Figure 5.3(b) Asessment of the workers movements

5.31 Nordic questionnaire

The Nordic Musculoskeletal Questionnaire (NMQ) was developed from a project

funded by the Nordic Council of Ministers. The NMQ is a standardized questionnaire

methodology allowing comparison of low back, neck, shoulder and general

complaints. The tool was not developed for clinical diagnosis but to obtain a statistical

review of MSDs.

The questionnaires consist of structured and multiple choice variants. Screening of the

musculoskeletal disorders serves as a diagnostic tool for analysing whether the

workers suffer from WRMSD’s. .

The general questionnaire was designed to answer the following question: "Do

musculoskeletal troubles occur in the given population, and if so, in what parts of the

body are they localized?".

With this consideration in mind, a questionnaire was constructed in which the human

body (viewed from the back) is divided into nine anatomical regions. These regions

were selected on the basis of two criteria: regions where symptoms tend to

Page | 31

accumulate, and regions which are distinguishable from each other both by the

respondent and a health surveyor.

Figure 5.31- Sample of the Nordic Questionnaire

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5.32 Input Values from Nordic Questionnaire

Questions/respondentsjob title sex duration of workpain during workpain after shifttime off interference with workhealth problems with workmonthly incomeOccupation location of painR1 1 1 1 1 2 1 2 2 12 4 2R2 3 1 2 1 2 2 1 2 3 4R3 3 1 1 2 2 2 1 2 12 4 0R4 4 1 1 1 2 2 1 2 12 4 0R5 4 1 1 2 1 2 1 2 12 4 0R6 4 1 1 1 1 3 1 12 4 5R7 4 1 3 2 2 2 1 2 10 3 0R8 1 1 1 2 2 2 1 2 10 4 0R9 3 1 1 2 2 2 1 2 10 3 0R10 1 1 2 2 2 2 1 2 10 4 0R11 1 1 1 2 2 2 1 2 10 4 0R12 3 1 2 2 2 2 1 2 12 4 0R13 1 1 2 2 2 2 1 2 12 4 0R14 1 2 2 1 1 2 1 2 12 3 0R15 3 1 2 2 2 2 1 2 12 3 0R16 1 1 1 2 2 2 1 2 12 4 0R17 3 1 1 1 1 2 1 2 12 4 2R18 3 1 1 2 2 2 1 2 12 4 0R19 3 1 1 1 1 2 2 2 10 4 7R20 3 1 1 2 2 2 1 2 12 4 0R21 3 1 1 2 2 2 1 2 0R22 3 1 1 2 2 2 1 2 2 2 0R23 2 1 1 1 2 22 2 1 12 4 5R24 3 1 2 1 2 2 1 2 10 3 0R25 3 1 1 1 1 1 1 1 2 3 8R26 3 1 2 2 2 2 1 2 12 4 8R27 1 1 3 2 1 2 2 1 12 4R228 3 1 1 2 2 2 1 2 12 4 0R29 2 1 3 2 2 2 1 2 12 4 0R30 2 1 2 2 2 2 1 2 0R31 2 1 1 2 2 2 1 2 0R32 2 1 1 1 1 2 2 2 2 3 2R33 2 1 1 2 2 2 1 2 2 3 0R34 3 1 2 1 1 1 2 2 4 3 5R35 4 1 1 2 1 1 2 2 12 3 0R36 3 1 1 2 2 2 1 2 12 3 0R37 2 1 1 2 2 2 1 2 12 3 0R38 2 1 2 2 2 2 1 2 12 3 0R39 2 1 1 2 2 2 1 2 12 3 0R40 3 1 1 2 2 2 1 2 12 3 0

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5.33 RULA

Apart from the above we also mean to assess the degree of movement the workers are

involved in using RULA [Rapid upper limb assessment]. This will provide us with the

various angles at which the work is carried out and hence assigning scores relevant to

them. The scores are added up to get a final value which will indicate the total

intensity of the exertion by the worker.

Figure 5.33 – Sample of the RULA scale

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5.34 Moore-Garg Strain Index

Strain index is a semi quantitative job analysis methodology that results in a

numerical score which correlates with the risk of developing distal upper extremity

disorders.

The ability to predict which tasks and combination of activities can lead to upper-

extremity, work-related musculoskeletal disorders (MSDs) will help to determine

which existing jobs require modification and which of those jobs have led to the

development of MSDs in the construction workers.

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Figure 5.34 – Sample of Moore Garg Strain Index

5.35 Input analysis of the Strain Index Score

Explaining the Moore-Garg Index variables

1. Intensity of Exertion (IEM) is a qualitative measure of the percent maximum

voluntary contraction that a task requires to perform one time. This is a function of the

force required and upper extremity posture. This analysis is done with the of RULA.

2. Duration of Effort (DEM) is- determined by timing the duration of the exertion

and is a measure of the physiological and biomechanical stress related to how long an

exertion is maintained.

Duration of Exertion = Duration of Effort / Cycle time

3. Hand/wrist posture (HPM) relates the anatomical posture of the hand which also

is assessed with the help of RULA.

4. Speed of Work (SWM) estimates the perceived pace of the task and accounts for

the additional stresses associated with dynamic work.

5. Duration of Task (DDM) per day is a measure of how much of the workday is

allocated to performing that task. In this construction industry all the workers were

allocated with more than 8 hours of work per day.

The SI score is the product of these 5 multipliers. Jobs with an SI score of 3 or less are

presumed safe or have a lower risk associated with them. Jobs with an SI score

between 3 and 7 are a tough call, and jobs with scores greater than 7 are hazardous.

SI Score = (IEM*DEM*HPM*SWM*DDM)/5

These scores are then used to calculate the mean and standard deviation in order to

calculate the probability of the number of workers without MSDs which is the P-

value.

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Respondants Workers with MSDs Workers without MSDs Total Sample size1 7.68 1.30 7.682 7.05 0.85 7.053 5.20 0.52 5.204 7.15 0.11 7.155 7.35 0.69 7.356 7.92 0.47 7.927 5.17 0.72 5.178 7.66 0.62 7.669 7.25 0.18 7.25

10 5.32 1.74 5.3211 0.43 1.3012 1.16 0.8513 0.21 0.5214 1.51 0.1115 1.47 0.6916 1.20 0.4717 0.43 0.7218 0.28 0.6219 1.82 0.1820 0.33 1.7421 0.90 0.4322 1.86 1.1623 1.92 0.2124 0.40 1.5125 1.97 1.4726 0.70 1.2027 1.46 0.4328 1.47 0.2829 1.59 1.8230 1.30 0.3331 0.9032 1.8633 1.9234 0.4035 1.9736 0.7037 1.4638 1.4739 1.5940 1.30

Total 10.00 30.00 40Mean 6.77 0.99 2.43Standard Deviation 1.10 0.59 2.96Z alpha/2 = Z 0.475 1.96 1.96 1.96sd/sqrtn 0.35 0.11 0.47CI 0.68 0.21 0.917621418

Table 5.34- Input to SI index

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Total population Non-MSD respodants MSD respodants0

5

10

15

20

25

30

35

40

45

Demographics of MSD affected workers

Masons Fitters Carpenters Plasteres

Resp

onde

nts

Figure 5.36- Demographics

Page | 38

5.4 DATA ANALYSIS

5.41 Qualitative Analysis

Qualitative research uses a naturalistic approach that seeks to understand some of the

phenomena in some context-specific settings, such as the real world setting where the

researcher does not attempt to manipulate the phenomenon. Qualitative research,

broadly defined, means "any kind of research that produces findings not arrived at by

all the means of statistical procedures or other means of quantification instead, the

kind of research that produces findings arrived from all the real-world settings”.

Qualitative analysis results in a different type of knowledge than does not change the

quantitative inquiry because one party argues from the underlying philosophical

nature of each paradigm, enjoying detailed interviewing and some of the other

focuses on the apparent compatibility of some the research methods, “enjoying the

rewards of both numbers and words”. This means that such methods like interviews

and observations are dominant in the naturalist process or supplementary in the

positive paradigm, where the use of survey serves shows in opposite order. Although

it has been claimed that quantitative researchers attempt to have disassociate

themselves as much as it possible from the research of process, qualitative

researchers have come to embrace their involvement and the role within the research.

When quantitative researchers speak of the research validity and reliability or they

are usually referring to a research that is it that credible while the credibility of a

qualitative research depends on the ability and very efficient of the researcher.

Although reliability and validity are treated separately in some quantitative studies,

these terms are not viewed separately in the qualitative research

5.42 SPSS Statistics

SPS software is a widespread used program for the statistical science in social

science. It is also used by the aid of market researchers, health researchers, survey

companies, government facility, education researchers, marketing organizations, data

miners, and others. The original SPS software manual has been described as one of

"sociology's most influential books of the universe" for allowing the ordinary

researchers to do their own kind of statistical analysis. In addition to statistical

analysis, the data management (case selection, file reshaping, creating derived data)

Page | 39

and data documentation (a metadata dictionary was stored in the data file) are features

of the base of software.

The base software consists a various statistics. In order to conduct the quantitative

analysis we conduct the following tests through SPS Software:

Reliability Tests - CRONBACH’S ALPHA

Prediction for identifying groups: Factor analysis

SPS software Statistics takes in data type, data processing, and matching files, which

together considerably simplifies programming. SPSS datasets have some two-

dimensional table structure, where the rows typically represent some critical cases

and the columns represent measurements (such as age, sex, or pain intensity). All data

processing occurs sequentially case-by-case through the file. The files can be matched

one-to-one and one-to-many, but not many-to-many.

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5.43 Reliability and validity of the questionnaire The questionnaire involves multi part health related topics but the items regarding

MSD complaints are taken into consideration to obtain repeatability in the results. The

participants will be asked about the complaints if it is regular or long lasting, if the

complaints were caused by the work and the degree to which they experience the

pain.

The difficulties within the questionnaire can be overcome with the reliability and

validity tests.

The term reliability refers to the consistency of a measure. Suppose the reliability of

a household scale is measured at weighing and re-weighing the objects at multiple

points of time. A re-test approach can be applied.

And hence the coefficient of variation is found which is determined by: Cv =

Standard deviation/mean. [ If Cv<0.2-stable , Cv>1.0-unstable ]

Validity involves the content validity, which measures the various aspects keeping in

mind of what item was under consideration, i.e. the consistency of questions relating

to the frequency of MSD’s.

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5.44 Reliability test- Cronbach’s Alpha

The Cronbach’s alpha is a measure of the internal consistency, i.e. the relatedness of

the items in the questionnaire. It is a coefficient of reliability. It can be written as a

function of the number if test items of the average test items and the inter-correlation

between the test items. The following reliability tests were conducted on the SPSS

Software 19.0 to obtain the coefficient of reliability.

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Page | 43

-

5.45 Validity test- Factor Analysis

Factor analysis is conducted to verify the construct validity of the questionnaire. The

exploratory factor analysis detects the factors that underlie the correlation between the

variables (questionnaire items)

Correlation Matrix

Sex

Durati

on of

work

Pain

durin

g

work

Pain

after

shift

Tim

e off

Interfe

rence

with

work

Health

proble

ms with

work

Job

title

Monthly

income

Occupatio

n

Location

of pain

C

O

R

R

Sex 1.00 -.269 -.113 -.092 -.272 -.113 .160 .020 -.143 -.022 .187

Duration of work -.269 1.000 .168 -.243 -.296 -.020 -.072 .104 .047 -.035 -.084

Pain during work -.113 .168 1.000 .117 .219 -.070 -.346 -.005 .323 -.047 -.091

Pain after shift -.092 -.243 .117 1.00 .558 -.198 -.545 .128 .433 -.167 -.589

Time off -.272 -.296 .219 .558 1.00 .142 -.546 .064 .299 -.109 -.458

Page | 44

E

L

A

T

I

O

N

Interference with

work

-.113 -.020 -.070 -.198 .142 1.000 .206 .110 -.507 .109 .207

Health problems .160 -.072 -.346 -.545 -.546 .206 1.000 .032 -.496 .163 .492

Job title .020 .104 -.005 .128 .064 .110 .032 1.000 .034 .734 -.163

Monthly income -.143 .047 .323 .433 .299 -.507 -.496 .034 1.000 -.117 -.578

Occupation -.022 -.035 -.047 -.167 -.109 .109 .163 .734 -.117 1.000 .180

Location of pain .187 -.084 -.091 -.589 -.458 .207 .492 -.163 -.578 .180 1.000

Si

g.

(1

-

ta

ile

d)

Sex .049 .247 .289 .047 .247 .165 .451 .192 .448 .127

Duration of work .049 .154 .068 .034 .453 .332 .265 .389 .417 .306

Pain during work .247 .154 .239 .090 .337 .015 .488 .023 .387 .291

Pain after shift .289 .068 .239 .000 .114 .000 .219 .003 .154 .000

Time off .047 .034 .090 .000 .194 .000 .350 .032 .254 .002

Interference .247 .453 .337 .114 .194 .104 .253 .000 .255 .103

Health problems .165 .332 .015 .000 .000 .104 .423 .001 .161 .001

Job title .451 .265 .488 .219 .350 .253 .423 .420 .000 .161

Monthly income .192 .389 .023 .003 .032 .000 .001 .420 .239 .000

Occupation .448 .417 .387 .154 .254 .255 .161 .000 .239 .137

Location of pain .127 .306 .291 .000 .002 .103 .001 .161 .000 .137

a. Determinant = .011

Page | 45

Component Matrix

Component

1 2 3 4

Sex -.273 -.155 -.293 -.639

Duration of work -.035 .052 .846 .248

Pain during work .387 .013 .372 .196

Pain after shift .778 .096 -.337 -.106

Time off .693 .170 -.445 .358

Interference with work -.340 .271 -.335 .705

Health problems with

work

-.798 .005 -.049 -.092

Job title .013 .928 .062 -.204

Monthly income .758 -.027 .283 -.315

Occupation -.260 .865 .059 -.194

Location of pain -.781 -.118 -.030 .064

Extraction Method: Principal Component Analysis.

a. 4 components extracted

5.46 Hypothesis Test for the Presence of MSD

Selection of statistical tests

The statistical test  to be selected depends on what we are comparing, number of data collection time points, number of observations and the type of data.

Statistical test is a test on the Null Hypothesis.  More specifically, it tests the Probability that the Null Hypothesis is valid.

Page | 46

Figure 5.46- Selection of statistical test1. What are you comparing? We have one set of data and comparing two

groups i.e. Workers affected by MSDs and not affected by MSDs.

2. How many data Collection time points? We have collected one set of data.

3. How many observations? We have 40 observations

4. What kind of data? Variables will be nominal, ordinal, interval, or ratio-level. A nominal level variable is a variable where the categories just have names. Ordinal data is data that is ordered, like first, second, third, etc. Interval-level data have equally spaced units, such as a Likert type scale. Ratio-level data are similar to interval level data, except that the data have a zero point in it, like amount or score.For our analysis, we use S.I index scores which are categorized as ratio-level data.

Since we are comparing two groups, collected as a set of ratio-level data, having 40 observations and the population standard deviation being known, we have chosen One-sample Z-test as our statistical test.

The one-sample z test is used when we want to calculate whether our sample comes from a particular population. In the one-sample Z test, we are comparing the mean calculated on some single set of scores to a known population mean.

Page | 47

We calculate the mean, the standard deviation of both categories from table 3 (MSD

and Non-MSD workers) to conduct a two-tailed t-test. We determined the mean of the

Strain Index of given total sample population (40) , workers affected by MSDs (10)

and workers not affected by it (30) as follow :

Mean SI Score of total Sample Size X= 2.43

Mean SI Score of workers not affected by MSDs µo= 0.99

Mean SI Score of workers affected by MSDs µ1= 6.77

The solution to this problem takes four steps:

(1) State the hypotheses

The first step is to state the null hypothesis and an alternative hypothesis.

Null hypothesis is workers are not affected by MSDs: µo = 0.99

Alternative hypothesis is workers are affected by MSDs: µo ≠ 0.99

Note that these hypotheses constitute a two-tailed test.

(2) Formulate an analysis plan

For this analysis, the significance level is 0.05. The test method is a one-

sample t-test.

(3) Analyze sample data

Using sample data, we compute the standard error (SE) and the degrees of

freedom (DF), and the t-score test statistic (t).

SE = s/sqrt(n)

2.96/sqrt(40)=2.96/7.07=0.468 

DF=n-1=40=39

t = (x - μ) / SE = (0.99 – 2.43)/0.468 = -3.0769

Where s is the standard deviation of the sample, x is the sample mean, μ is the

known hypothesized population mean and n is the sample size.

Page | 48

Since we have a two-tailed test, the P-value is the probability that the t-score

having 39 degrees of freedom is less than -3.0769 or greater than 3.0769.

We use the t Distribution Calculator to find P (t < -3.0769) = 0.04, and P (t

>3.0769) = 0.0008. Thus, the P-value = 0.0008+ 0.0008= 0.0016

(4) Interpret results.

Figure 5.47 Normal distribution curve regarding P-value

Since the P-value (0.0016) is lesser than the significance level (0.05), we can

reject the null hypothesis of the workers without MSDs and thus accepting the

alternate hypothesis which is the presence of MSDs among workers of the

construction site.

Hence by using statistical tools, we provide with the data taken from the

construction site, proving with the P-test, that there is a presence of MSDs

within the construction site.

6. CONCLUSION

Results of the questionnaires and semi-structured interviews are revealed that the

workers have at various periods of experienced pain/discomfort arising from their

work. The large amount of number of the semi-skilled and unskilled workers who

dosent have some access to or have a very little or some knowledge of the ergonomics

risk factors inherent in their respective profession, resort for steps to taking of drugs

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µ = 0.99

0.0008 0.0008

like pain relievers very often to reduce the amount of pains. The parts of the body

mostly are affected by the pains which are associated with the upper level body

movements; shoulders, neck, wrists and the upper back. Most of the previous skilled

workers identified as the process of manual lifting of heavy loads and poor work

environment as the major cause of the pain or discomfort. The results of this study

revealed that we’re able to assess statistically, the various areas are the upper body

affected, the degree of pain, and the presence of musculoskeletal orders among the

construction workers. There are several measures that can be taken to mitigate the

injuries and practise better ergonomic principles are followed. These factors include:

Process of redesigning of workplace to reduce the frequent scene of bending and

twisting of the trunk torso by the workers, massive ergonomics risk factors are

involved and awareness campaigns for all the things to do some of the sensitize the

semiskilled and unskilled workers on the dangers of WMSDs.

7. FUTURE SCOPE OF THE PROJECT

7.1 Framework for the Muscle Fatigue Analysis

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In most fatigue evaluation methods, muscle fatigue evaluation might not only

available for static postures, but not suitable for dynamic working process. . These

techniques might not accurate though enough to localize MSD risks to certain

muscles. Hence there is a need to find a model that expresses the dynamic

movements of the workers. These are justified with the use of PLIBEL (Plan

för Identifiering av Belastningsfaktorer: “method for the identification of

musculoskeletal stressfactors which may have injurious effects”) and the use of Muscle Fatigue

Analysis. For this purpose, a model is suggested based on the factors taken as input data which is then

utilised in a form of virtual environment with the human stimulation data and processed in software

to obtain certain criteria to judge the various means of not improving the work environments along

with the proper assessment of the workers of some movements. The given frameworks consists

of three main modules: some of the virtual environment module, data collection

module , with evaluation module. The module of virtual environment is obtained by

creating the necessary situations. Data collection module is obtained by evaluating

dynamic manual handling jobs consists of motion, forces and personal factors. To

achieve the motion data, some of the motion capture technique can be applied to

achieve the motion information which can be achieved from some existing human

simulation tools such as PLIBEL. The virtual human is modelled with the motion data

obtained from PLIBEL doing the manual handling job in the virtual environment. The

evaluation module takes all the input data to evaluate the manual operation. In this

given module, evaluation criteria some of the aspects of the manual operation are

predefined in the framework, some of the postures analysis criteria and fatigue criteria

and discomfort from the criteria. With these criteria,we know the different aspect can

be evaluated by processing the input data. And since an ideal condition can be

provided for workers.

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Virtual Human

Virtual Interaction

Virtual Environment Comfort Criteria

Fatigue Test

Efficiency Criteria

Posture Criteria

Model 7- Muscle Fatigue Analysis

Page | 52

Human Motion

Interaction

Environment

Simulated Human Motion

Fatigue Analysis

Comf

ort Analysis

Posture Analysis

OWESObjective

WorkEvaluation

System

Existing Simulation Software

Motion Capture

Haptic Interface

Virtual Reality

7.2 Input to human simulation through 3DSSP Software

3D Static Strength Prediction Program 3D SSP is based on over thirty years of research at the centre of ergonomics regarding the biomechanical causes and static strength capabilities of with respect to the outside environment on the physical ability of the workers.The posture entry is done with the aid of an inverse set of kinematics algorithm by conducting the effect of load and its manipulations on the human body. However some of the environmental factors such as nature of the object being handled, workplace obstructions, traction and some of the feet-floor interface, and worker apparel cannot be found.

The summary from the analysis can be provided as follows: Task Input SummaryBody segment angles and hand locations and hand force magnitude and direction.Analysis SummaryHand forces and l5 or s1 disc compression and percent capable and balance, and coefficient of the friction.AnthropometryAnthropometric data including body segment lengths, centre of gravity, and body segment weights.Strength CapabilitiesFor each joint articulation: resultant moment produced with some of the strength capability to generate a moment larger than the resultant moment.

Figure 7.1- Model of the program

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Figure 7.2 – Modelling the mannequin to the proposed display model along with the input values to the posture angles and the load carried (weight carried with it)

Figure 7.3- Report summary about the various regions of the body affected by the load inputs

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8. REFERENCES1. Creative Research Systems Survey software -

http://www.surveysystem.com/index.htm

2. Nordic questionnaire -

http://www.uresp.ulaval.ca/backpaindefs/en/PDF/KuorinkaPaper.pdf

3. OSHA - http://elcosh.org/document/1648/d000560/preventing-

muskuloskeletal-disorders-in-construction-workers.html

4. Rapid Upper Limb Assessment - ergo-plus.com/wp-content/uploads/ RULA -

A-Step-by-Step-Guide1.pdf

5. Moore-Garg Strain Index - J. Steven Moore and

ArunGargpersonal.health.usf.edu/tbernard/HollowHills/StrainIndexM12.pdf.

6. Hypothesis test for mean - http://stattrek.com/hypothesis-test/mean.aspx?

Tutorial=AP

7. OSHA : Ergonomics Program Management Guidelines-

https://www.osha.gov/Publications/OSHA3123/3123.html

8. Risk assessment on Filipino construction workers James Renier T. Domingo,

Ma. Theresa S. De Pano

9. Status survey of occupational risk factors of manual material handling tasks at

a construction site/Pradip Kumar Ray, RatriParida, IshaSaha

10. Moore-Garg Strain Index -

personal.health.usf.edu/tbernard/HollowHills/StrainIndexM12.pdf.

11. A Conceptual Model for Work-related Neck and Upper Limb Musculoskeletal

Disorders, Thomson J Amstrong PhD, Peter Buckle PhD, Lawrence J Fine.

12. Handbook of OSHA construction Safety and Health, Secon Edition.

13. New Jersey Institute of Technology, Paper on Ergonomics Assessment of

Airport Baggage Handler.

14. Occupational Medicine 2004;54:297–303

15. www.sjsu.com/faculty/gertsman/StatPremer/hyp-test.pdf

16. Framework for Dynamic Evaluation of Muscle Fatigue in Manual Handling

Work - https://arxiv.org/ftp/arxiv/papers/0809/0809.3181.pdf

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