03-05-2014, 03:56 PM
A Framework of Project Risk Management for the Underground Corridor Construction of Metro Rail
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Abstract
In this paper, we discuss a method of measurement of project risk, based on the expected
value method (EVM). Project risk management primarily comprises cost and schedule
uncertainties and risks associated with each activity of the project network. We have
identified the major risk sources and quantified the risks in terms of likelihood, impact
and severity in a complex infrastructure project for the construction of an underground
corridor for metro railways. A case study of the underground metro corridor in the
capital city of an emerging economic nation of South Asia has been considered for this
research work. The methodology for this work was the response from the experts
associated and involved in this and other similar projects in metro rail. The risk analysis
for the determination of risk cost, risk time, expected cost and expected time of the
project has been carried out by the expected value method. Based on this study we find
that the project cost overrun and time overrun can be about 22.5 % and 23.4 %
respectively, if we use the expected value method.
Introduction
Risk management is an essential and integral part of project management in major
construction projects. For an infrastructure project, risk management can be carried out
effectively by investigating and identifying the sources of risks associated with each activity
of the project. These risks can be assessed or measured in terms of likelihood and impact.
The major activities in underground corridor construction consist of feasibility studies, design,
traffic diversion, utility diversion, survey works, shoulder piling and king piling works, timber
lagging works, soil and rock excavation, construction decks, steel struts, rock anchors, sub-
floor drainage, waterproofing, permanent structure works, mechanical and electrical
installations, backfilling and restoration works. We have developed a questionnaire survey
and personally interviewed experts from the underground corridor project. In this process, we
have identified the risks at various phases of the project starting from the feasibility phase to
the completion of the project. Then we have used the expected value method (EVM) to
compute the effect of risky sources in terms of their impact and severity and also the overall
effect on the project time and cost.
CASE ANALYSIS
The sample stretch under analysis consists of a 530 metre(m) cut and cover tunnel connecting
station S5 and S6, a 290m S6 station box and a 180m cut and cover over run tunnel adjoining
the S6 station box. S6 station being the terminal station, the down trains towards this station
after leaving station S5 will travel through the 530m cut and cover tunnel and enter the
platforms of the terminal station S6. After the commuters vacate the train at this terminal
station, this down train will travel through the 180m over run tunnel and will be converted
into an up line train which will travel from station S6 to S1.
Risk Severity Analysis using the Concept of CLF and CIF
Risk severity can be computed from equation (6). The product of the likelihood and impact of
a risk can be considered as the severity of that risk. This concept can be extended for multiple
risk sources in a work package, the likelihood and impact of which can be expressed in terms
of CLFj and CIFj respectively. Thus for the underground corridor construction project, the risk
severity of each major activity of the project is computed as presented in Table 6.
Application of Monte Carlo Simulation
We apply the Monte Carlo simulation to predict the outcome of the expected time (ET) and
expected cost (EC) of all the possible paths of activities as represented in the network diagram
of the project (figure 1). The Monte Carlo simulation also takes into account the effects of the
near critical paths becoming critical. By carrying out a detailed path analysis of the project
network diagram, we observed that the path A-C-E-D-G-I-P-T has the longest duration of
3786 days. Hence this path is considered as the critical path of the project network (refer
figure 1). The corresponding cost for the completion of activities along this path is INR 1220
Million. It is also observed that the probability of the successful completion of the project
within the stipulated time and cost frame is only 4% (0.625 x 0.730 x 0.738 x 0.681 x 0.720 x
0.623 x 0.616 x 0.602 = 0.040). Path A-B-D-G-I-P-T is a near critical path with a probability
of about 4.8% for successful completion within the stipulated time and cost frame. There are
chances of this path becoming critical.
CONCLUSION
Project risk management which primarily comprises schedule and cost uncertainties and risks
should be essentially carried out for complex urban infrastructure projects such as the
construction of an underground corridor for metro rail operations. In the current research
work we found that the number of major and minor risks involved during the construction of
the project, from the feasibility to the completion of the execution, are large, and if not treated
or mitigated properly, the probability of successful completion of the project within the
stipulated time and cost frame will reduce. This will have a direct impact on the efficiency
and profitability of the organization.