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INTERNATIONAL JOURNAL OF SOCIAL SERVICE AND
RESEARCH
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RISK OF BROWNFIELD DURING CONSTRUCTION STAGE: CASE STUDY
OF PLTGU PROJECT IN INDONESIA
Nasrudin Rozaq*,
Jati Utomo Dwi Hatmoko, Ferry Hermawan
Departement of Civil Engingeering,
Universitas Diponegoro,
Semarang, Indonesia
Email: [email protected]*
Abstract
Projects at the
brownfield location cannot be separated from potential hazards related to
geotechnical conditions and the existing project site. The construction phase
is carried out at a location in the middle of an already operating factory.
Lack of understanding of site characteristics and minimal use of the technology
used can result in the project not meeting what was expected. This study aims
to identify brownfield risk events during the construction phase of the PLTGU
project development in Indonesia. This research uses quantitative and
qualitative methods with a case study approach. Primary data were collected
using documentation, field observations, survey questionnaires and structured
interviews. The results of the study identified 23 (twenty three) and 6 (six)
main risks based on the rankings, namely: 1) Groundwater level risk, 2)
Location infrastructure damage, 3) Flood risk, 4) Structural damage and
structural settlement, 5) Land subsidence, 6) Leakage of existing underground
pipes. risks affecting project performance during the construction phase. The
results of the study reveal that these risk events are risks that must be
managed by project management during the construction phase.
Keywords: Brownfield risk;
construction phase; land
Received 29 November 2022, Revised 10 December 2022, Accepted 20 December 2022
INTRODUCTION
Brownfield
is a term used by experts to define land or buildings that have been previously
used or developed and are not fully used, even though they are partially
occupied or utilized, may also be vacant, abandoned or contaminated Alker et al., (2000). A brownfield project is
defined as a project carried out within existing operating facilities as
opposed to a greenfield project which was built from scratch Malik, (2021). The use of brownfield land
is used to avoid obstacles in the licensing process and land acquisition.
Project
development at the brownfield location has many uncertainties, such as the
geotechnical location and the existence of the existing De Sousa, (2000). These projects tend to
require large amounts of money to manage
the contamination in them before they are used for construction. Luo, Catney and Lerner, (2009)
found that there are many obstacles in the brownfield construction, including
those related to geotechnical hazards caused by the density and strength of the
residual soil material Štefaňák, (2019), heterogeneous
materials mixed with the original soil during various stages of expansion over
a long period of time, causing geotechnical site characterization to play an
important role, because contamination stored in it Štefaňák, (2019).
The
Brownfield project is implemented in an environment with existing facilities
and ongoing operations Farrance and Taylor, (2012), the project is
more complex due to the complex network of interdependencies and conflicting
relationships between operations at the location of Brahm and Tarziján, (2015). A number of
challenges and constraints on the project often result in cost overruns and
schedule delays if not addressed adequately. The implementation of brownfield
projects is often affected by a lack of definition resulting in scope growth,
low efficiency of brownfield work due to permits, limited layout or simply poor
access to facilities Hassan et al., (2016). The need for
careful planning and scheduling to determine the potential for criticality and
uncertainty of field conditions, using resources effectively to optimize space
constraints, and developing strategic responses to reduce risks by taking into
account safety, convenience, and implementation time De and Rout, (2022).
In
this study, brownfield risk is defined as an event or occurrence that involves
hazards related to soil conditions that affect the project objectives. The
construction stage is a critical stage during project implementation, risk events
during the construction stage can be positive and negative. Positive risks can
have a positive impact on the project, such as budget savings, time
acceleration and so on. Negative risk is something that is not wanted to happen
or can have a negative impact on the project, for example an increase in the
budget, potential delays. This study aims to investigate brownfield risk events
that occur during the construction phase of a PLTGU construction project in
Indonesia.
METHOD
The research method used in this study is a
mixed approach, combining quantitative and qualitative approaches. The purpose
of integrating quantitative and qualitative data is to ensure completeness, as
qualitative evidence can support survey data to explain unidentified relationships.
Meanwhile, to answer this research, descriptive qualitative and explanatory
methods are used, which aim to analyze, describe, and
summarize various conditions, situations from various data collected in the
form of interviews or observations of the researched problems that occur in the
field with a case study approach on the project. This study chose a case study
of the PLTGU project development in Indonesia. Primary data were collected
using documentation, field surveys and structured interviews with related
information. Other related data in this study are supporting documents for the
literature on brownfield hazards and
risks.
Purposive sampling method was used in this
study to avoid bias from the results of the study, respondents were selected
based on criteria that were in accordance with the objectives of this study,
namely: experienced in working on PLTGU development projects by sharing
brownfield and greenfield characteristics.
In this study, the Likert scale was used to
quantify brownfield risk. Likert scale is a scale that can be used to measure
the opinion of a population of events that occur. The questionnaire survey was
chosen to collect data from service users and service providers. The author has
distributed questionnaires to 30 personnel who are experienced in working on
PLTGU projects. This study uncovers risk events that occur during the
construction phase.
A.
Case Study
Gas and
Steam Power Plant (PLTGU) is a combination of PLTG and PLTU, where the heat
from the exhaust gas from the PLTG is used to produce steam which is used as
the working fluid in the PLTU. PLTGU consists of two parts of the building, the
main building is the turbine generator building and Heat Recovery Steam
Generator (HRSG), and the Balance of plant (BOP) building consists of the
Condensate Pump, Forced, draft fan, Induced draft fan, Circulating Water Pump
building. Stations. The construction of PLTGU unit 3 (three) is an expansion of
the block 2 generator unit. Several buildings such as the Balance of Plant (BOP) which is a supporting building in
a series of Power plant work processes, one of which is the Circulation Water
Pump Station building which has the main function of pumping seawater which
flows through concrete pipes to the condenser tubes. Then the water in the
condenser tube is used to condense the low pressure (LP) output stream in the
HRSG to drive a steam turbine. After the evaporation process is complete, the
evaporating wastewater is processed at the Wastewater Treatment Plant and then
discharged back into the sea through the Outfall network.
Figure 1. Case study location
One of the
buildings that became the object was the Circulation Water Pump Station
construction, which was built on contaminated land and was built at a depth of
-9.2 m from the original ground level and -12.7 m from the face of the
landfill. The original soil condition is peat soil and the ground water level
is -0.5 m from the original ground water level.
B. Descriptive Analysis of Research Respondents
Characteristics
of respondents include work experience in the construction industry and the
respondent's position in construction companies. The description of working
experience in the construction industry in this study is divided into 4
categories, namely having worked in the construction industry for between 5-10
years, 10-15 years, 15-20 years and more than 20 years. Figure 2. shows the
results of the identification of respondents' experiences in the construction
sector.
Figure 2. Description of the respondents' work experience.
Identification
results show that 30% of respondents have 5-10 years of experience, 30% have
10-15 years of experience, 33% have 15-20 years of experience and 20% have more
than 20 years of experience. This shows that most of the respondents already
have sufficient experience in handling construction projects. The work
experience of research respondents is very influential on the results of this
study and is important to review. This is used because it can see the extent to
which respondents can understand and assess risk events that occur in projects
that they have or are currently working on and see their effect on project
completion time performance.
Job
descriptions of respondents in this study were divided into 5 categories,
namely as senior site engineering, construction manager, engineering manager,
project manager, implementer and other positions. Figure 3. shows the results
of the identification of research respondents' positions.
Figure 3. Job description of research respondents
From the identification results
obtained, 20% of respondents have a position as a senior site engineer, 16%
have a position as a construction manager, 10% have a position as an
engineering manager, 7% have a position as a project manager, and 47% others
such as quality control inspector, project control. The position of the
respondent is very important to review, because the respondents needed in this
study are devoted only to those who work in the field during project
implementation. From these results, it can be seen that some of the research
respondents understand the risk events on the project being worked on and their
effect on the performance of the project completion time.
RESULTS
AND DISCUSSION
Based on the results of observations and analysis, this study
identified brownfield risks during the construction phase. The results of
identification and analysis using RII (relative Importance index) consist of 23
risks that affect during the construction phase of the PLTGU Project, which are
shown in Table 1.
Table 1
Brownfield risk during the construction phase
|
Code
|
Risk
|
RII
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Rank
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R1
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Placement of materials and equipment at the project site
|
0.780
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15
|
|
R2
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Mobilization of project resources
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0.760
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19
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R3
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Limited work locations
|
0.787
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14
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R4
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Existence of underground service networks such as existing
pipelines
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0.840
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7
|
|
R5
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Flooding due to
high tides and puddles for days at the project site
|
0.873
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3
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R6
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Risk of claims due to non-compliance with the work
agreement is in the contract
|
0.807
|
12
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R7
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Risk of subcontractor price bidding
|
0.780
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16
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R8
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Risk of swelling of project budget
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0.833
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9
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|
R9
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Payment of project owner
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0.780
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17
|
|
R10
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Resource planning and scheduling
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0.833
|
10
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|
R11
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Availability of materials according to contract
specifications
|
0.707
|
23
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R12
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Delay in completion of work by subcontractors
|
0.793
|
13
|
|
R13
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Risk of
clarity of working drawings
|
0.720
|
22
|
|
R14
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Risk of design changes during the construction phase
|
0.740
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21
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R15
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Construction methods are not in accordance with field
conditions
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0.837
|
8
|
|
R16
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Risk of bill of quantity of work
|
0.747
|
20
|
|
R17
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Difficulty in installing heavy machinery and equipment
|
0.767
|
18
|
|
R18
|
Work error (rework)
|
0.833
|
11
|
|
R19
|
Structural damage
|
0.867
|
4
|
|
R20
|
Structural drop
|
0.867
|
5
|
|
R21
|
Damage to infrastructure around the project site
|
0.880
|
2
|
|
R22
|
Presence and high ground water level
|
0.887
|
1
|
|
R23
|
Land consolidation
|
0.867
|
6
|
Of the 23 (twenty three) identified risks,
there are 6 risks that are very serious. influence during the construction
phase, based on the analysis results as follows:
A. Risk of Existence of ground water level
Groundwater
generation and its effects are often a major consideration in the design of
construction project work. Changes in groundwater levels outside of normal
seasonal variations are not considered while major changes can occur, such as a
lack of groundwater pumping capacity which will cause the water level to rise,
pooling in the lower construction area and tunnels, and can change the soil
load Brassington, (1986).
Figure 4.
Existence of groundwater level
The accumulation of groundwater can increase the movement of
groundwater contaminants to adjacent work sites, have an impact on work
activities and can damage building materials as shown in Figure 4. Some work
activities are still carried out in the presence of groundwater.
B.
Damage to Location
Infrastructure
The
availability of infrastructure utilities is an advantage of the brownfield
project and infrastructure damage is the responsibility of the contractor, as
shown in Figure 5. Damage to drainage channels can cause water logging around
the project site. Meanwhile, road damage causes discomfort for road users in
industrial complex environments.
Figure 5. Damage
to Infrastructure around the Site
During the
construction phase the unstable soil condition of the site due to contamination
caused some soil damage to the infrastructure which was difficult to repair.
This event resulted in additional work during the construction phase such as
sewer damage which could pose a risk of flooding.
C. Flood Risk
Surface
water flooding can be caused due to the interaction of complex factors, such as
inappropriate hydrology of the location, intensity and duration of rainfall,
soil surface characteristics and the design of surface drainage and sewer
systems.
Figure 6. Surface
water and tidal flooding
Surface
water flooding can be severe during high-intensity rains. Exclusively
convective rainfall events can infiltrate into the soil, but in areas with
contaminated soil it causes impermeable soil surface Jenkins et al., (2018). During the construction phase the events in Figure 6.
Several times these events occurred which hampered the implementation and
damaged the material and accelerated corrosion.
D. Structural damage and structural settlement
Events of
structural damage and structural settlement are shown in Figure 7. It is the
impact of the condition of soil movement during the construction phase.
According to Castaldo et al., (2013)
in their research damage to reinforced concrete
structures can be affected by land subsidence due to excavations around the
work site.
Figure 7.
Structural damage and structural settlement
Based on the results of interviews
with project workers during the structural work in Figure 7. At the
construction, there are several works such as the installation of a bona pipe
weighing 10 tons per segment below ground level and excavation. The events in
Figure 3 such as observations and research conducted by Castaldo et al.,(2013).
E.
Land subsidence
The
movement of land subsidence in Figure 8. is an event that occurred during the
construction phase, the results of observations found several cases of land
subsidence in cavities with varied depths. According to Hills, (1994)
stated that the mechanism of creeping soil
settlement, otherwise known as secondary consolidation, is one of gradual
rearrangement of material particles, which results in a decrease in the void
ratio and an increase in the density of the material. This behavior
occurs over a long period of time under constant stress of environmental conditions, Charles, (2008); Brink and Tinto, (2021)
Figure 8.
Creeping decrease in soil
According
to Day, (2013)
in Brink and Tinto, (2021) revealed that standing water is the main trigger for the
decrease in collapse of the embankment. This is due to an increase in water
content in the embankment due to infiltration of surface water downwards,
through walls, utility lines, leakage of infiltration channels, and rising
groundwater levels after the dewatering operation stops.
F.
Leakage of existing
underground pipeline
Leakage of
existing pipelines containing fuel close to construction works can
endanger the health of workers at the work site and can cause explosions and
fires. Basically the brownfield project is carried out with the condition of
the factory location still operating. It does not rule out the possibility of
finding some underground services such as gas pipelines, fuel pipes and power
lines. Field observations found risk events as shown in Figure 9.
Figure 9. Existing pipe leakage
Observations
in Figure 9. found damage to the fuel pipe network which is still active and
has leaks. The results of the interview revealed that before the leak occurred,
the outer physical condition of the pipe experienced a severe level of
corrosion. Construction activities with limited locations cause pipes to crack
and leak.
Construction
work is a critical stage, the occurrence of risk events during the construction
stage causes losses and schedule swelling. The results of interviews with the
project team revealed that the contractor's lack of understanding and
experience working on projects with brownfield characteristics, neglecting the
dangers that should have been mitigated at the beginning of the project,
because the lack of familiarity with technology, and the large repair budget,
were the main factors. The condition of environmental uncertainty during the
construction phase exacerbates the hazard. Construction at the brownfield site
requires geotechnical test planning, data collection, analysis and
interpretation of field and laboratory results in a timely and cost-effective
manner.
CONCLUSION
The construction phase of the brownfield
project has complex challenges, because it has to run side by side with a
factory site that is still operating. Uncertainty about the dangers caused such
as geotechnical conditions and the existence of an existing site, can cause
delays in work time. Lack of technological familiarity and experience in
running the project will have an impact on cost loss. The results of
observation and analysis of case studies during the implementation of the PLTGU
construction project have identified 23 (twenty three) risks and 6 (six) main
risks based on ratings, namely: 1) Risk of Existence of Groundwater, 2) Damage
to Location Infrastructure, 3) Flood Risk, 4) Structural damage and structural
deterioration, 5) Land subsidence, 6) Leakage of existing underground pipe. The
results of the interview reveal that the event is a risk that the project
management must face during construction. This event is the risk that will
affect the most in terms of performance, cost and time during the PLTGU
construction phase.
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