Impact of Variation Orders on Time and Cost in Mega Hydropower Projects of Pakistan

Hanif, Hashim Muhammad; Khurshid, Muhammad Bilal; Lindhard, Søren Munch; Aslam, Zuhaib

doi:10.21315/jcdc2016.21.2.3

Cited by 23 publications

(17 citation statements)

References 13 publications

(15 reference statements)

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“…Many researchers have evaluated the causes of design changes based on the construction stages like pre-planning, planning, design and construction [34,36,37] whereas few researchers have categorized the sources of design change from the perspective of Clients, consultants and contractors [6,9,29]. The dynamics can be classified into internal and external factors which are adopted in this paper.…”

Section: Causes Of Design Changes Impacting the Cost Overrunmentioning

confidence: 99%

Design Changes in Construction Projects – Causes and Impact on the Cost

2019

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Isolation of design phase from construction has made the design changes inevitable in construction projects. Extensive literature appraisal has acknowledged the detrimental effect of design changes on project performances. However, the impact and causes of design changes have been divided up, either separately or project specific. As a result, the relationship between impact and causes of design changes could not be established for general construction. The primary objective of this paper is to examine the impact of design changes on project cost and identifying actions responsible for these changes. The objectives of the study were achieved through a systematic review of past literature published in well-established journals, and contents analyzed. From the extensive literature review, it was established that the design change is one of the predominant factors to cost overrun, and in some cases, may upshot into cost overrun between 5 and 40% of the project cost. Also, many causes of design changes resulting in cost overrun within the perspective of the owner, consultant, and contractors are explored. Some projects experienced closure as a result of owner induced design changes, although these changes may not be significant in number. Design changes as a result of consultants and contractors in some cases might have reduced impact but are frequent. For each consideration, most events leading to design changes can be eliminated by improving on communication and coordination between stakeholders. The main contribution of this research is to bring together the impact and causes of design changes on cost under one platform for effectively managing the design process.

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Section: Causes Of Design Changes Impacting the Cost Overrunmentioning

confidence: 99%

Design Changes in Construction Projects – Causes and Impact on the Cost

2019

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“…From the literature review, it is found that there are 18 main causes of the variation works identified by most researches ( [5], [6], [2], [7], [3], [8], [9], [10], [11], [12], [13], [14], [15], [16] and [17]). The causes of variation order are described as follows:…”

Section: The Causes Of Variation Workmentioning

confidence: 99%

A review of causes of variation order in the construction of terrace housing projects in Malaysia

Mohammad

Hamzah

2019

MATEC Web Conf.

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Variation order refers to any changes from the scope, plan, specification or contract document in the construction project. This changes of work is a common problem in construction projects in Malaysia. It is inevitable in any construction project and this problem can become more serious when variation order causes work progress to be impaired as a results it increased the construction time and cost that affects the construction industry in Malaysia. This paper critically review the causes of variation order in the construction industry on the double-storey terrace housing project in Malaysia. The discussions began with the construction industry in Malaysia and then related parties involved in the construction industry. The extensive local and abroad literature review on the definitions of variation order and analysis of past studies conducted on variation order and the previous study of the prediction model of variation. The extensive literature on variation order in the construction of building project may help to improve the performance in term of time, cost and quality of the construction of building projects in Malaysia.

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“…The prediction of the production progress is sometimes problematic in on-site construction (Russel et al 2004). The unpredictability of task duration is caused by varying labor productivity, uncertainty in quality of estimates, and the possibility of changes during construction (Hanif et al 2016;Russel et al 2014;González et al 2010). Howick (2003) and Flyvberg et al (2009) have underlined that uncertainty in estimates have a huge impact on time-, cost-, and quality performance.…”

Section: Introductionmentioning

confidence: 99%

Impact of Activity Sequencing on Reducing Variability

Lindhard

Hamzeh

González

et al. 2019

J. Constr. Eng. Manage.

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Variation in production is deemed a major reason behind producing waste in onsite construction operations, resulting in a workflow that's full of delays and interruptions. To reduce the negative impact of waste in construction, production managers need to address the causes of variation that's resulting in such waste. This paper explains the way to reduce the effects of variation in construction by changing the tasks' sequence arrangement. The study analyzes the effect of some different tasks' sequence arrangements on each of the production gap, crew waiting time, and production delay by simulating a group of work tasks and changing the task sequence arrangement from linear to parallel. Accordingly, one hundred work activities have been simulated in 98 different sequence designs, using a stochastic discrete-event simulation model, during which the number of parallel activities are systematically increased. The main finding from the studied configuration is that; arranging tasks in parallel increases waste, while it reduces project duration. Moreover, waste resulting from variation is found to be an additional cause for waste when accelerating the production. Finally, it was revealed that the impact of variation on the tasks' sequence highly depends on how often the schedule is updated. This study helps production managers to better understand of how the tasks' sequence arrangement affects production performance in onsite construction operations.

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Impact of Variation Orders on Time and Cost in Mega Hydropower Projects of Pakistan

Cited by 23 publications

References 13 publications

Design Changes in Construction Projects – Causes and Impact on the Cost

Design Changes in Construction Projects – Causes and Impact on the Cost

A review of causes of variation order in the construction of terrace housing projects in Malaysia

Impact of Activity Sequencing on Reducing Variability

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