AN ASSESSMENT OF SAFETY RISK FACTORS DURING INSTALLATION AND DISMANTLING OF TOWER CRANES ON CONSTRUCTION SITES

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AN ASSESSMENT OF SAFETY RISK FACTORS DURING INSTALLATION AND DISMANTLING OF TOWER CRANES ON CONSTRUCTION SITES

Abstract

The process of erection, dismantling and alteration of heights in tower cranes are major safety determinants on construction sites and can result to fatal accidents if the risks involved are not properly managed. Risk factors associated with this process have been identified by some researchers but, no effort was made to scientifically analyse these factors. Hence, the research aimed at assessing safety risk factors during installation and dismantling of tower cranes with a view to establishing the most significant risk factors. A well-structured questionnaire was used to collect data from safety managers, equipment managers and team leaders of installation and dismantling operation with respect to probability/likelihood of occurrence and degree of impact for safety risk factors.Data obtained wereanalysed using descriptive statistics (mean and percentages). From the results, relative significance index score (RSIS) was obtained and evaluated on a 5×5 matrix risk rating scale to determine the criticality of safety risk factors. Results showed that ―abrasion‖had the highest probability of occurrence with a mean value of 3.63 and as such, the most probable factor that occur on site. The study also found that ―fracture of a wire rope during dismantling‖ had the highest degree of impact with a mean value of 4.63 and can result to fatality on site. The latter also had the highest RSIS of 15.6 indicating a high risk factor. This research concludes that fracture of a wire rope during dismantling is a high risk factor and could result from poor maintenance culture that is generally lacking on construction sites.

Table of Contents

Title Page………………………………………………………………………………………………………………….. i

Declaration………………………………………………………………………………………………………………. ii

Certification……………………………………………………………………………………………………………. iii

Dedication……………………………………………………………………………………………………………….. iv

Acknowledgement…………………………………………………………………………………………………….. v

Abstract………………………………………………………………………………………………………………….. vi

Table of Contents…………………………………………………………………………………………………… vii

List of Tables…………………………………………………………………………………………………………… ix

List of Figures………………………………………………………………………………………………………….. x

List of Appendices…………………………………………………………………………………………………… xi

1.0     INTRODUCTION…………………………………………………………………………………………… 1

1.1 Background of the Study…………………………………………………………………………………….. 1

1.2 Statement of Problem………………………………………………………………………………………….. 4

1.3 Justification of the Study……………………………………………………………………………………… 6

1.4 Aim and Objectives……………………………………………………………………………………………… 7

1.4.1Aim………………………………………………………………………………………………………………… 7

1.4.2Objectives………………………………………………………………………………………………………….. 7

1.5 Scope and Limitations…………………………………………………………………………………………. 7

1.5.1Scope……………………………………………………………………………………………………………….. 7

1.5.2Limitations…………………………………………………………………………………………………………. 8

2.0 LITERATURE REVIEW…………………………………………………………………………………… 9

2.1 Overview of Safety Issues in Construction Industry……………………………………………… 9

2.1.1Safety risk assessment in construction……………………………………………………………………. 9

2.2 Accidents in the Nigerian Construction Industry………………………………………………… 10

2.3 Tower Cranes and their Safety Issues………………………………………………………………… 11

2.4 Installation and Dismantling Operation in Tower Cranes……………………………………. 12

2.5 Risk Assessment………………………………………………………………………………………………… 14

2.5.1Risk identification…………………………………………………………………………………………….. 16

2.5.2Risk analysis…………………………………………………………………………………………………….. 17

2.5.3Risk components……………………………………………………………………………………………….. 20

2.5.4Risk matrix and scales……………………………………………………………………………………….. 20

2.5.5Importance of risk assessment…………………………………………………………………………….. 21

2.6     Review of Tower Crane Studies……………………………………………………………………… 21

2.7   Review of Factors Affecting Safety during Installation/Dismantling of Tower

Cranes.………………………………………………………………………………………..23

2.8     Reviewed Safety Risk Factors…………………………………………………………………………. 27

3.0 RESEARCH METHODOLOGY………………………………………………………………………. 29

3.1 Research Design………………………………………………………………………………………………… 29

3.2 Population, Sample Size and Sampling Technique………………………………………………. 30

3.2.1 Population……………………………………………………………………………………………………….. 30

3.2.2Sample size………………………………………………………………………………………………………. 30

3.2.3Sampling techniques………………………………………………………………………………………….. 31

3.3 Data Collection Method……………………………………………………………………………………… 31

3.4Description of Instrument…………………………………………………………………………………… 31

3.5 Data Analysis…………………………………………………………………………………………………….. 32

4.0 DATA PRESENTATION, ANALYSIS AND DISCUSSION……………………………… 35

4.1 Questionnaire Administered………………………………………………………………………………. 35

4.2     Respondents Profile……………………………………………………………………………………….. 35

4.3 Probability of Occurrence for Safety Risk Factor……………………………………………….. 37

4.4 Degree of Impact for Safety Risk Factors…………………………………………………………… 39

4.5     Evaluation of Safety Risk Factors…………………………………………………………………… 41

5.0 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS…………………………. 43

5.1 Summary of Findings………………………………………………………………………………………… 43

5.2 Conclusion………………………………………………………………………………………………………… 44

5.3 Recommendations……………………………………………………………………………………………… 45

5.4 Contribution to Knowledge……………………………………………………………………………….. 45

REFERENCES……………………………………………………………………………………………………… 46

APPENDICES……………………………………………………………………………………………………….. 53

CHAPTER ONE

INTRODUCTION
Background of the Study

A crane safety analysis and recommendation report carried out in Singapore by Annex (2009) indicates that in 2008, there were 162 crane-related accidents, injuries and dangerousoccurrences, a 27% increment from 128 cases in 2007. However, most of the cases involve less serious non-fatal injuries crane accidents can undoubtedly result to big and severe damage to physical properties and human lives.Tower cranes are used on construction sites as lifting equipment for their combination of height and lifting capacity. Tower crane accidents, however, are likely to be fatal because of the weight of the objects and the heights to which they are lifted (Beavers, Moore, Rinehart and Schriver, 2006). U.S. Labour statistics recorded 632 crane-related construction worker deaths from 611 crane incidents and 17 multiple death incidents resulting in 38 deaths from 1992 to 2006 (Bureau of Labour Statistics, 2008).

Orji, Enebe and Onoh(2016) posit that construction processes in Nigeria are characterized by unsafe practices leading to accident that leaves severe consequences on both the project and the workers. Accidents in building construction sites, whether minor or fatal could result to injuries, loss of resources, partial or permanent disability and death in case of fatalities. In an analysis of types of accident that usually occur in construction sites, injury from the use of equipment ranked first among nine (9) other types of accident examined.

Idoro (2011) asserted that although there is no reliable construction accident/incident data in Nigerianevertheless, a study carried out on 40 contractors in 2006 showed that the rate of accidents and injuries in the Nigerian construction industry were high and the most suitablesafety ratios were 2 accidents per 100 workers and 5 injuries per 100 workers.

Kadiri, Nden, Avre, Oladipo, Edom, Samuel, and Ananso (2014) stated that as the growth rate of construction industry increases in Nigeria, this also causes an increase in competition of projects to be executed between construction firms which are however, achieved at the expense of the workers safety and their welfare.

In this way recognizing the different causes and impact of accidents on construction sites and proposing ways and methods for decreasing these accidents ought to be recognized. Erection/climbing/disassembling of tower cranes is a possibly unsafe process including working at heights, awkward postures, lifting and adjusting parts of huge size and mass and introducing temporary support systems. These are all often performed under significant time pressure, as a result of this, the need for road closures, suitable daylight hours or short weather windows as the case maybe are pertinent (Safework, 2016).

The most unsafe process that can prompt fatalities at construction sites is the installation/dismantling of tower cranes; for example, in 2012, the fall of a tower crane amid disassembling at the University of Texas, USA claimed the lives of two workers (Occupational Safety and Health Administration, [OSHA] 2012).

There have been five lethal accidents identifying with tower crane use amid 2002– 2006 in Hong Kong, with three workers losing their lives in July 2007 alone. One of such mishap in July 2007 resulted to two fatalities and five genuine wounds. The accident occurred amid the disassembly procedure, with workers on the tower crane as it was moving down (Ting, 2007).

Also in a related development, out of the 571 incident cases of crane related accidents that happened from 2000 – 2009 in the U.S as examined by Zhao (2011), 41 cases which amounted to 7.18% occurred during assembly/disassembly. He further went ahead to say that 22 cases (23.40%) of the 94 cases that occurred from 2007-2009 resulted directly from the operations of assembly/disassembly.Recent study of tower crane accidents in Korea from 2001-2011, showed that out of the 38 fatal accident cases involving tower cranes, 68.4% of the accidents resulted from the installation/dismantling operation (Shin, 2015).

Effective safety management is to make the environment safe, to make the job safe and to make workers safety conscious. In recent years, many developed countries have considered safety as one of the important management issues of construction projects, especially, personal safety (Chen, Lu, and Huang, 2011).

Ali and Muhamad (2016) opines that without proper safety management of construction machines at construction sites, accidents could happen. Cranes are the machines that contribute to highest fatality rate in construction industry. It was concluded that cranes are machines with high risk and should be operated with safety management and strong communication between crane operator and signalman.

Hola (2010) stated that, the use of machines and equipment‘s are factors that generate hazards on construction sites and these hazards could cause accidents which result to injuries or even loss of lives. Safety measures at construction sites assist to prevent unforeseen incidents. Accidents at construction sites may result to loss of life and involve huge expenses in terms of cost. The occurrence of fatalities in construction sites normally leads to site closure for accident investigation, loss of man/machine hours, high labour turnover, loss of organisation reputation, loss of output, payment of burial expenses/compensation/insurance claims for the dead as the case may be (Emiedafe, 2017).

The consequences of building construction accidents are enormous and cannot be easily quantified, though inevitable but could be controlled to prevent minor or serious consequences to safety of workers (Orji et al., 2016).

Identifying hazards and assessing risks in the workplace ensures safe work environment and healthy working conditions. The staff will feel well and the production and services will run easily. Hazard and risk factors coming from the workplace and working conditions ought to be assessed efficiently/systematically in the work environment. In the event that the hazards can’t be wiped out totally, their noteworthiness to the health and safety of workers (magnitude of risk) ought to be evaluated and measures taken to minimize the risk to a reasonable level or to dispense it altogether (Vitharana, Subashi De Silva and Sudhira De Silva, 2015; Odeyinka and Dada, 2016; Finland Centre for Occupational Safety, (FCOS) 2017; Nordlof, Wiitavaara, Hogberg andWesterling, 2017).

Factors that influence construction site safety because of the use of tower cranes have attracted only little attention; they are normally addressed indirectly and mostly within the more extensive treatment of site safety or of crane work in general (Nunnally, 2000). Research focusing on crane safety that clearly suggests tower crane related risk factors or safety hazards is limited (Shapira and Lyachin, 2009). Hence the need to critically examine safety issues regarding the installation and dismantling operation of tower cranes.

1.2                                                         Statement of Problem

Tam and Fung (2011) carried out a study on safety of tower cranes in Hong Kong where they discovered that the process of erection, dismantle and alteration of heights in tower cranes are major safety determinants on construction sites. In the examination, they found out that even though erection/dismantle workers were provided with the manufacturers instruction, they and their co-workers seldom have a look on it prior to implementing the stated procedures. They stated that this is so because, they have no time to do that and they can only rely on their practical experience.

However, relying on practical experience without following stated procedures by manufacturers during erection/dismantling of tower cranes lead to over confidence that brings about human errors and can result to accidents during this operation (Shin, 2015).

Occupational Safety and Health Branch [OSHB] (2012) also agreed that accidents may occur during crane erection, dismantling and height alteration operations due to failure to follow the correct procedures specified by the crane manufacturers. In order to avoid dangerous and expensive consequences a proper risk assessment is required to identify the hazards inherent in the operation and also the hazard which could result from adjacent activities.

If risk levels could be anticipated reliably and easily, construction workers and managers (company safety manager, site engineer, project manager, superintendents, etc.) could better mitigate the risks in numerous ways to ensure safety (Rozenfeld, Sacksand Rosenfeld, 2009; Umeokaforet al.,2014).

Chi, Sangwon, Dae and Yoonjung (2015) opines that, risk identification and cautioning can improve the safety of workplaces. By organizing high recurrence risk factors to viably control accident occurence and deal with the probability of lethal injuries on construction sites when an accident is unavoidable, enables/helps safety managers to comprehend the nature of construction accidents and plan for key risk mitigation.

However, Jannadi and Almishari (2003) having concerted to the fact that assessment of risk is crucial for improving safety, they went ahead to say that precise evaluation is not really necessary and that an estimated predicted level of risks will suffice for the safety managers to take necessary actions.

In construction sector, the percentage of work accidents is more extended as compared with other areas. In this context, it might be considered as necessary and useful for an extended analysis of risk factors and even more identification of risk factors in construction as related to work safety on sites (Bogdan and Alina, 2017).

Yu, Ding, Zhou and Luo (2014) in his study, found that failure to carry out identification and analysis of safety risk is a major factor that causes accidents in China metro construction as it ranked 8th amongst the 40 factors identified as accident causal factors.

Practically, it is impossible for a project manager to focus attention on managing all identified risk factors hence, the reason to carry out a proper analysis to help prioritize those identified (Odeyinka and Dada, 2016).

Researchers have not done much in scientifically addressing safety issues pertaining to tower crane erection/dismantling operations which has been stated by Neitzel, Seixas and Ren (2001); Beavers et al.(2006); Zhao(2011); OSHB(2012); Shin(2015)as a dangerous operation that could hamper safety on construction sites.

Although, Shin (2015) was able to identify some factors affecting safety during installation and dismantling of tower cranes, but no attempt was done to systematically analyse these factors to measure qualitatively or quantitatively the level of risk these factors poses to safety or their degree of influence on safety so as to establish the most significant ones where the limited resources for safety can be utilized to minimize the inherent risk.

1.3                                                         Justification of the Study

The essence of this research cannot be overemphasized as our construction sites would continue to be a potential death trap if proper measures are not taken to manage the risk involved especially with tower crane usage whose accidents may not occur frequently but very disastrous when they do occur. Proper identification and analysis of all the risk factors involved during installation and dismantling operations would help us to determine the individual and combined effect as they affect safety which would aid in the accurate measurement of risk and development of adequate risk response with respect to tower crane safety on our construction sites. On the other hand this would also help in the better allocation and utilization of limited resources. It is anticipated that the result of this research if implemented would help minimize accident occurrence on our construction sites especially with respect to tower crane usage.

1.4                                                         Aim and Objectives

1.4.1    Aim

The aim of this research is to assesssafety risk factors during installation and dismantling of tower cranes with a view to enhancing safety on site.

1.4.2    Objectives

  1. To identifythe safetyrisk factors during installation and dismantlingof tower cranes in construction sites.
  2. To determine theprobability of occurrence for each safety risk factor.
  • To determine the degree of impact of the safety risk factors.
  1. To evaluate the safety risk factors based on established risk rating scales.

1.5                                                         Scope and Limitations

1.5.1    Scope

This research is limited to opinions of safety managers, team leaders and equipment managers practicing in Abuja, Lagos and Kaduna. This is so because their nature of work have exposed them to the use of tower cranes and they would have gained the requisite experience needed to give correct insight about the information required. Abuja, Lagos and Kaduna were chosen because they are known with high rate of construction activitiesinvolving the use of tower cranes. Safety risk factors during the operation of tower cranes were not considered for the research, only those associated with the process of installation and dismantling of tower cranes were considered.

1.5.2     Limitations

  1. The fewer number of research so far carried out on installation and dismantling of tower cranes made it difficult to draw up inferences for the study.
  2. The study could not cover all the states in Nigeria which could have made the findings more generalized.     AN ASSESSMENT OF SAFETY RISK FACTORS DURING INSTALLATION AND DISMANTLING OF TOWER CRANES ON CONSTRUCTION SITES

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