Analysis of occupational accident risk in breakwater construction and floating piers

In every implementation of the project, work accidents can occur which result in injury or other losses. One of the projects that has the potential for work accidents is the floating dock construction work. The purpose of writing this paper is to find out the dominant hazard variable in floating piers and breakwater construction work, to know the causes and effects of the dominant hazard variable, and to know the right dominant risk control risk control in floating wharf construction work. This research begins with hazard identification using several sources and also direct discussions with resource persons who understand this work. Then a questionnaire was distributed to obtain the likelihood and severity values of the existing hazard variables. From the results of distributing the questionnaires, tests were carried out using validity and reliability tests on each hazard variable that might occur. The results of the tests carried out obtained a valid hazard variable and were then analysed using HIRA which was assisted by a risk matrix. So that the results of the analysis are known to be the dominant hazard variable, namely workers falling and sinking into the sea. Furthermore, an analysis of the two variables is carried out to determine the causes and also the impact of risks that can occur using a bow-tie diagram to reduce the occurrence of dominant potential hazards.


Introduction
A port is an area of water that is protected against waves, which is equipped with sea terminal facilities including a pier where ships can moor for loading and unloading of goods, and warehouses where goods can be stored for a longer time, while waiting for delivery to the destination area [1].The port is a gateway to enter a region or country and as a connecting infrastructure between regions or islands in that region or country.In the (physical) port construction work, there are several related works including preparatory work, north and south side breakwater work, floating wharf work, dredging work, development area work, construction of land facilities (terminal building), implementation of a safety management system construction and others.In the (physical) port construction work, there are several related works including preparatory work, north and south side breakwater work, floating wharf work, dredging work, talud work, development area work, construction of land facilities (terminal building), implementation of a safety management system construction and others.In the construction work of a floating wharf contains several sources of danger both from the environment, the use of heavy equipment, materials and so on.Inappropriate implementation of work methods can result in the risk of work accidents which can disrupt the course of project activities.
One way to minimize this is by conducting a work accident risk analysis.Risk analysis can be interpreted as a procedure to recognize a threat and vulnerability, then analyse it to identify an accident, and find out how the impacts can be eliminated or reduced.This paper discussed the risk assessment in construction project work, especially in the construction of floating docks is required to deal with various risks that may occur.There are several methods to conduct risk assessment as described in Table 1.
The method used in this study combines Hazard Identification and Risk Assessment (HIRA) and Bowtie Analysis.Hazard Identification and Risk Assessment (HIRA) is used to identify potential job hazards by defining the characteristics of the hazards that may arise and assessing the risks that arise through risk assessment using a risk assessment matrix to obtain the most dominant risks.Meanwhile, Bowtie Analysis is used to analyze the impacts and causes that can be generated through initiating events or top events so that they can provide preventive recommendations and mitigating controls that will be used.

No References
Objectives Methods [2] to develop methodology for investigation of Risk Based Maintenance (MIRBA) FTA, AHP [3] to apply the HAZOP methodology in process and safety operations in the oil production industry HAZOP analysis; hazard identification [4] to change old-fashioned HAZOP industrial practice and improve safety performance in oil and gas industry HAZOP analysis [5] to understand the limit values and the safety range for every parameter with the aid of graphs and tables and so they achieved a quantitative HAZOP to resume the data they have found.

HAZOP, Risk
Assessment [6] is to evaluate the safety of crude oil tankers using the methodology of Formal Safety Assessment (FSA).
And provides a general approach to safety assessment and discusses the evolution of risk acceptance in recent decades.
Formal Safety Assessment, HAZOP, HAZID [7] to promote safety and knowledge transfer on the LNG fuel chain to interested stakeholders, such as port operators, maritime instructors, port authorities, and stakeholders in planning, licensing, and emergency management practices related to LNG handling.
HAZOP, HAZID [8] as a technique for examining the systematic and efficient application of HSE engineering by exploiting the HAZOP systematic risk analysis technique and a quantitative risk derivation method, which is an advantage of the Safety Integrity Level HAZOP [9] provide an overview of the Hazard and Operability (HAZOP) and Hazard Identification (HAZID) studies as risk management techniques.The paper discusses the application of HAZOP and HAZID studies in identifying and analyzing potential hazards in various industries, including the chemical process industry, oil and gas industry, and other process industries.
HAZOP, HAZID [10] to propose qualitative and quantitative approaches for identifying and prioritizing different hazards associated with decommissioning of offshore wind farms.In the maritime industry, there have been many studies discussing risk assessment such as fire analysis in the offloading process [11], anchor handling [12], natural gas pipelines [13], container terminal activities [14].In addition, in the field of construction, there are also many topics discussed related to risk assessment, such as research [15] which discusses the use of HIRA in construction projects, [16]which combines the use of HIRA and HAZOP in risk assessment, [17] which discusses the risk analysis model for offshore engineering project to determine the risks associated with a particular activity and the justification factors for proposed improvements.

Data collection
The data used in this study is the result of observations and discussions with workers who are directly involved in projects related to the work of the Sanu Port Facility Development project, Bali.The data obtained is in the form of detailed data on activities, work methods and several HSE documents related to this research.Hazard identification carried out in research is carried out by conducting discussions with project work implementers or supervisors.After the data is in accordance with what is in the field and also approved by the project executor, then the author compiles a questionnaire to be distributed to several workers related to the project work.Table 2 shows the hazards identification in floating pier construction work based on the respondents.

Risk analysis using HIRA (Hazard Identification and Risk Assessment) method
Risk analysis begins with processing data from questionnaires that have previously been distributed to predetermined respondents.The results of the questionnaire are used to measure the likelihood and severity of each activity variable that has been determined.Furthermore, the likelihood and severity of each hazard variable will be tested using validity and reliability tests to determine the accuracy of the instrument in measuring what we want to measure in research and also to determine the consistency of research instruments from time to time.Invalid and reliable variables will be eliminated later.The results of the multiplication between the likelihood and severity of the valid variables will later be plotted into the risk matrix to obtain the most dominant hazard variable risk results.

Likelihood and severity
After distributing the questionnaires to several respondents, the likelihood and severity of each hazard variable will be known.The following is the likelihood and severity of each hazard variable in floating wharf construction work as seen in Table 4.

Validity and reliability check
From the results of the likelihood and severity that have been obtained, then a test is carried out to find out the accuracy and consistency of each of the existing variables.To test the validity using Bivariate Pearson correlation (Pearson Moment Product) and Corrected Item-Total Correlation.
Whereas for reliability testing using the Cronbach Alpha test to state whether the variable is consistent when tested repeatedly. ( In testing the validity of the question is considered valid if the calculated R value is greater than R table (N = 6, R table = 0.707 with a significance of 5%).The following is the result of testing the validity of the likelihood and severity of each variable as seen in Table 5.
The variables of likelihood and severity which invalid are eliminated and not included in the next stages.The next data processing is risk assessment with a risk matrix.From table 6 above it is found that the Cronbach's Alpha coefficient on the floating pier work item is 0.967 (ri > 0.7) which means that the test items used are reliable/can be used repeatedly.

Hazard identification and risk assessment (HIRA)
From the results of the validity and reliability tests that have been carried out, valid and reliable hazard variables are then used for further analysis by multiplying the likelihood index and severity index to later be plotted in the risk matrix to determine the dominant hazard variable.
To calculate the likelihood and severity index the author uses the equation below: With,  =   (1 / 5)  =    = The results of calculating the likelihood index and severity index can be seen in Table 7. (3) Risk assessment using a risk matrix is carried out by multiplying the value of the likelihood and severity index which have previously been calculated.The hazard variables contained in the hazard identification are plotted as a whole into the risk matrix to find out which hazards are acceptable or unacceptable.Based on the risk matrix shown in Table 8, there are 5 risks that must be eliminated immediately because they are in the red area namely IF, 4A, 4B, 5E, and 5H codes.Based on the risk matrix, the five risks are unacceptable, so risk control must be carried out because they can affect the floating dock construction work.These dominant risks will be further analyzed using a bowtie diagram to determine the causes, impacts and mitigation of these risks.Bowtie diagram of the dominant variable can be seen in Figure 1.

Risk assessment in breakwater construction work
In carrying out a risk assessment on breakwater construction work, the analytical steps carried out are the same as when carrying out a risk assessment of floating pier construction work.Starting with hazard identification, calculating likelihood and severity, conducting validity and reliability tests, calculating likelihood index and severity index, and later obtaining the most dominant risk in breakwater construction work as seen in Table 9.Based on the risk matrix that has been made, there is one dominant hazard variable that occurs in breakwater construction work, which is variable 2B (worker being hit by heavy equipment).The dominant risk variables will be analyzed further using a bowtie diagram to find out the causes, impacts, and mitigation to prevent the risk variables from arising again.The bowtie diagram for this risk variable can be seen in Figure 2.

Conclusion
Based on the results that has been carried out in this study it can be concluded that there are 5 activities in the floating pier construction work and the extreme hazards is workers falling into the sea, that can be seen in Figure 1.Whereas in the breakwater construction work there is one dominant variable, namely workers who are hit by heavy equipment which can be seen in Figure 2.

Figure 1 .
Figure 1.Bowtie diagram on the risk of falling and sinking into the sea

Figure 2 .
Figure 2. Bowtie diagram on the risk of workers being hit by heavy equipment

Table 2 .
Hazards Identification in Floating Pier Construction Work

Table 3
shows the hazards identification in breakwater construction work based on the respondents.

Table 3 .
Hazards Identification in Breakwater Construction Work

Table 4 .
Likelihood and Severity Rating in Floating Wire Construction Work

Table 5 .
Validity Test of Hazard Variables in Floating Pier Construction Work

Table 6 .
Reliability Tests on Hazard Variables in Floating Pier Construction Work

Table 7 .
Likelihood Index and Severity Index

Table 8 .
Assessment with The Risk Matrix on Floating Works