CONTENT

Editorial

1. Istvan Hajnal:
THE DETERMINATION OF THE MARKET VALUE OF WORKS IN PROGRESS WITH PROBABILITY GRAPHS

2. A. Kazaz, S. Ulubeyll,B. Er, V. Arsian, M. Atici, A. Arsian:
fRESH READY-MIXED CONCRETE WASTE IN CONSTRUCTION PROJECTS: A PLANNING APPROACH

3. David Grau, Amin Abbaszadegan:
IMPACT OF REAL-TIME PROJECT CONTROL ON CAPITAL PROJECT COST AND SCHEDULE PERFORMANCE

4. Zoltan Sebestyen, Tamas Toth:
RANKING PROJECTS IN MULTI-CRITERIA ENVIRONMENT

5.Miklos Hajdu:
HISTORY AND SOME LATEST DEVELOPMENTS OF PROCEDENCE DIAGRAMMING METHOD

6. Yi Su, Gunnar Lucko:
COMPARISON AND RENALSSANCE OF CLASSIC LINE-OF-BALANCE AND LINEAR SCHEDULE CONCEPTS FOR CONSTRUCTION INDUSTRY

7. Farnaz Sadeghpour, Shabtal Isaac:
A COMPARATIVE STUDY OF OWNER, CONTRACTOR, AND CONSULTANT PERSPECTIVE ON THE SELECTION CRITERIA FOR SUBCONTRACORS

1. Istvan Hajnal:

THE DETERMINATION OF THE MARKET VALUE OF WORKS IN PROGRESS WITH PRBABILITY GRAPHS

Abstract:
One of the most apparent signs of the international real estate crisis is the many unfinished construction investments. The various states and professional organizations are attempting to mitigate investment risks with regulations and methodology instructions, and, thus inspiring new confidence, to kick-start financing, which is the engine driving the real estate market. New methods and approaches are necessary in the area of real estate valuation also, to ensure that the market value of works in progress could be accurately determined at all times, thereby facilitating the management of risks and reinforcing the confidence of the investors. The author of the article reviews and evaluates the methods with which the value of works in progress can be estimated well, and which can replace the static, simplistic approach currently used by appraisers. While comparative methodology is not suitable to tackle the problem, as the first practical step, in the net replacement cost based valuation approach the Market Value of the land, as value-forming factor, must continuously be examined. The income-based calculation approach can easily be made suitable for the determination of the Market Value of works in progress. If the works are suspended, the author suggests applying calculations with the probability trees as being the most efficient method for estimating the Market Value.

Keywords: Real Estate; Probability Graph; Risk Mitigation; Valuation; Work in Progress

2. A. Kazaz, S. Ulubeyll,B. Er, V. Arsian, M. Atici, A. Arsian

fRESH READY-MIXED CONCRETE WASTE IN CONSTRUCTION PROJECTS: A PLANNING APPROACH

Abstract:
In the current study, how planning and truck-mixer based
waste amounts per 1 m3 fresh ready-mixed concrete (RMC) can
be determined was presented. Toward this aim, the formation
process of the fresh RMC waste in construction projects was
first introduced in a detailed manner, together with an in-depth
literature review in this specific domain of the construction
engineering and management. Then, the measurement procedure
of the waste amount or coefficient of the fresh RMC was
revealed and discussed as a practical and creative planning
knowledge. Hence, a useful and realistic waste management
perspective about the cost and potential environmental savings
of the RMC waste was drawn.

Keywords: Concrete waste; Construction projects; Fresh concrete; Project planning; Ready-mixed concrete

3. David Grau, Amin Abbaszadegan:

IMPACT OF REAL-TIME PROJECT CONTROL ON CAPITAL PROJECT COST AND SCHEDULE PERFORMANCE

Abstract:
This article assesses the combined influence of information integration and automated data analytics on project performance. To this end, retrospective data on 78 completed projects, with a total installed value of $8 billion, was collected. The level of internal and external information integration and automated analytics were used as surrogates of real-time project controls for statistical analyses purposes. Indeed, non-parametric statistical techniques were used to assess the impact of such technologies on cost and schedule performance. Overall, teams with a sophisticated degree of information integration and automated data analytics can control their projects with more reliable information and in a proactive manner so that informed decisions can be timely made on behalf of the project and the organization.

Keywords: Real-time; Project controls; Cost; Schedule; Performance; Project management

4. Zoltan Sebestyen, Tamas Toth:

RANKING PROJECTS IN MULTI-CRITERIA ENVIRONMENT

Abstract:
In the construction industry, the way the company manages its projects is a fundamental issue. IT tools supporting project portfolio management have become widely available and widely used, however, some of their processes still significantly need to be refined and made more accurate. Choosing the right project is a vital element of their way to success or failure. This also means that when a building project becomes value-destroying, it has to be suspended, or even stopped. Making such decisions is vitally important for the company. The paper presents an integrated project prioritization model, which includes both financial and non-financial criteria. The conceptual idea is to integrate the financial element with the most widely used non-financial points of view that are already applied, tested and published in the relevant literature separately. The authors go over the steps of PPM one by one and in addition to the ranking of the outlined projects, also briefly summarize the basics of monitoring.

Keywords: Portfolio management; Project prioritization; Project selection; Project ranking criteria; Monitoring

5.Miklos Hajdu:

HISTORY AND SOME LATEST DEVELOPMENTS OF PROCEDENCE DIAGRAMMING METHOD

Abstract:
Although the birth of Precedence Diagramming Method (PDM) is not as radiant as of CPM or PERT, but it is definitely the prevailing scheduling technique of our times. This popularity is due to its modeling flexibility over other techniques and the easy-to-understand mathematical model behind the technique. However, even this technique has its own limitations; modeling overlapping activities in a proper way seems to be a never-ending debate. The reason of this can be found in
the fundamentals of PDM technique; the four precedence relationships that form connections between the end-points of the activities, with constant production speed. These fundamentals of PDM have their own consequences to scheduling practice; it is more and more apparent among professionals that activity overlapping in PDM cannot be modeled adequately. Different solutions were proposed for solving this problem from the application of negative lag, through the combination of SS and FF relations to the fragmentation of activities. All these solutions have their shortcomings. Probably the fragmentation technique has led to the development of point-to-point type of relation that can connect any arbitrary points of the dependent activities. The objective of this paper is to analyze the pros and cons of different solutions that are used for modeling overlapped activities, then to show how newly defined point-to-point relations can be used for this purpose. Algorithms that handles point-to-point relations with minimal and maximal lags are also presented. The main finding of the paper is that newly developed point-topoint relations are better from theoretical and practical point of view than the solutions based on traditional precedence relationships, but they still cannot provide theoretically perfect solution for overlapping. This paper is the fully extended version of a paper building on the results already presented on the Creative Construction Conference [1].

Keywords: Precedence Diagramming Method, Activity overlapping, Point-to-point relations

6. Yi Su, Gunnar Lucko:

COMPARISON AND RENALSSANCE OF CLASSIC LINE-OF-BALANCE AND LINEAR SCHEDULE CONCEPTS FOR CONSTRUCTION INDUSTRY

Abstract:
Line-of-Balance (LOB) is a useful analytical tool for repetitive activities in construction projects, which allows showing which crew is assigned to what repetitive work unit of an activity. LOB is closely related to the linear scheduling method, but possesses some challenges: It must be clarified how it counts, as previous studies displayed an apparent measurement gap at the origin, implicitly representing that LOB starts at the first unit finish. Slopes in linear scheduling and LOB are different, even though both portray a measure of progress of an activity. This paper therefore tracks evolution and current use of LOB versus linear schedules. Its contribution to the body of knowledge is threefold: First, based on a literature review, LOB is found to be rooted in Activity-on-Arrow (AOA) diagrams, which makes it event-centered, not progress-centered. Differences in representing the start and productivity between LOB and linear scheduling are reviewed and explained both mathematically and graphically. Second, different LOB concepts are extracted and assessed to facilitate comparing LOB from its original use in manufacturing against the limited application of its objective chart in the construction industry. Third, a mathematical formulation based on singularity functions is developed, which can model staggering, continuity, and interruptability scenarios. Fourth, the repetitive nature of LOB and LSM enables resource-specific equations that model the level of detail of individual crews performing individual tasks.

Keywords: Line-of-Balance; Linear Scheduling; Modeling; Singularity Functions

7. Farnaz Sadeghpour, Shabtal Isaac:

A COMPARATIVE STUDY OF OWNER, CONTRACTOR, AND CONSULTANT PERSPECTIVE ON THE SELECTION CRITERIA FOR SUBCONTRACORS

Abstract:
Up till now, most research on the selection of subcontractors in construction projects has focused on the factors considered by the main (general) contractors. The goal of this study is to identify the factors that other main stakeholders, namely clients and consultants, believe should be taken into account when selecting subcontractors. The paper presents the results of a survey of experts from various backgrounds in the construction industry and conducts a comparative study of their perspectives in factors that should be considered in selecting subcontractors. The results of the survey show that there are similarities and dissimilarities between perceptions of respondents with different background. For example, nearly all the respondents identified subcontractor’s past experience in similar projects and subcontractor’s available resources, as the most important factors that should be considered in selecting subcontractors. However, while respondents from contractor organizations identified the lowest bid as one of the most important factors, those from consultant and client organizations identified subcontractor’s safety record, compliance with project schedule, and safety programs and past safety record as their top considerations in selecting subcontractors. The paper provides an extensive statistical analysis to identify the impact of stakeholder’s background on their perspective in the importance of factors that should be considered in selecting subcontractors and discusses the similarities and dissimilarities in their perspectives.

Keywords: Subcontractor; Construction bids; Selection; Comparative; Statistical analysis