As construction projects become more complex and challenging to execute, project managers need to develop work schedules that consider as many objectives as are critical to project success. A work schedule designed to optimize all these objectives is likely to enhance project performance. However, achieving a balance among these objectives is difficult because they frequently conflict with each other. Many optimization models have been developed over the years that can factor in different objectives. Although previous optimization studies have contributed to the body of knowledge by individually adding one or two objectives to the classical time–cost trade-off (TCT) problem, none of these studies simultaneously optimized more than three or four objectives at a time. Clearly, there is a need for a multiobjective optimization model to generate work schedules that increase the likelihood of achieving as many project objectives as necessary. This study was motivated by the need to fill this research gap. The objective of this study was to develop a mathematical multiobjective optimization model for the time–cost–quality–schedule flexibility-resource fluctuation trade-off problem in small-scale construction projects. The proposed model is novel because it (1) considers five important objectives of construction project scheduling at the same time, (2) quantifies all objectives to provide an accurate reflection of construction site conditions, and (3) objectively determines the optimal compromise solution using a distance-based method rather than subjectively from a set of Pareto-optimal solutions. The applicability of the proposed model is demonstrated with an illustrative example. The key results of this study are as follows: (1) the optimal solution obtained depends on the project manager's priorities relative to the objectives; and (2) in optimization problems with more than two objectives, considering the objectives one at a time may result in misleading solutions, because the effects of the other objectives are ignored in this optimization. Consequently, multiple objectives must be considered simultaneously rather than one at a time. The proposed model is expected to provide project managers with a work schedule that balances five or more objectives, increasing the chances of successful project performance.
Incentive/disincentive (I/D) contracting has developed from basic cost- and profit-sharing arrangements between an owner and a contractor. To motivate the contractor to put in an extra effort to realize one or more project objectives of an accelerated, costly, and complex undertaking, the owner may offer an award to the contractor. The owner may also threaten the contractor with a penalty if the objectives are not met. This paper reviews the fundamental incentive/disincentive arrangements in contracting literature. Then, results are reported of a survey conducted on a sample of Illinois DOT highway contracts that included I/D provisions. The survey investigates whether there exists an agreement or disagreement between IDOT's and the contractors' perceptions of I/D contract provisions. The findings reveal how I/D contract milestones are established, how they are executed, what kind of work practices the contractor uses to fulfill I/D targets, and how the contracting parties perceive I/D contracts' effectiveness as opposed to non-I/D contracts. Certain issues pointed out by the respondents as problematic and in need of further refinement in I/D applications are also highlighted.
Public-Private Partnerships (PPPs) have gained significant importance in academia, government, and the construction industry over the last three decades. As a result, numerous studies have been published on the topic. These studies investigate various issues associated with PPP projects such as the length of the concession period, the selection of the private consortium, and the laws, rules and regulations that govern PPP implementation. However, there is a lack of systematic overview about issues with particular attention to financial aspects. This paper presents the outcome of a literature review that has been conducted to collect information about financial issues encountered in PPP implementation. This review included a total of 33 papers published in major journals and conference proceedings in the construction field in the last 25 years. At the end of the review, it was possible to identify a set of 19 financial issues that were grouped into five categories, namely (1) financing system, (2) financial market, (3) transaction costs and delays, (4) the public agency, and (5) the private consortium. The choice of focusing on this theme was prompted by the fact that the other issues (i.e., social, legal, and political) are all linked to financial issues. The identification of the salient issues related to financial aspects in PPPs is expected to contribute to the state-of-art in PPP research and implementation as it can pave the way to an empirical investigation that can in turn lead to a streamlining of the PPP processes throughout the world.
Change orders occur during construction, and usually increase both construction cost and project duration. This paper investigates how change orders are related to the bidding environment. The data used in this study were collected from 74 public building construction projects awarded by the Public Building Commission of Chicago in the seven-year period 2008-2015. The contract values range between $0.3-$70 million, and the total worth of the projects is a little over $1.1 billion. While delay may result in liquidated damages for contractors, increase in project cost can cause financial problems for owners. It is in the interest of owners and contractors to study similar past projects, and to observe how change orders are affected by the level of competition in bidding. Owners must budget for contingencies, and contractors must adjust their resources in anticipation of change orders. It would therefore be quite desirable for owners and contractors to be able to predict the dollar amount and duration implications of potential change orders by making use of past historical data. The prediction of the dollar amount and duration implications of potential change orders before the construction starts can alert construction owners and contractors to potential delays in total project completion time and potential overruns in total project cost. Knowledge about potential change orders creates a predictable environment and improves the relationship between owners and contractors. The results of this study indicate that contractor-driven change orders are positively related to the difference between the lowest and the second lowest bids.
Measuring the performance of joint ventures has been an important research topic for a few decades. No consensus on an appropriate definition and measurement of performance of international joint ventures (IJVs) has yet emerged, and the validity of the underlying measures is still questionable. In this study, the construct validity of measures that define IJV performance in construction is evaluated using data obtained through a questionnaire survey. A second-order performance construct is proposed, which is measured by means of project performance, partner performance, performance of IJV management, and perceived satisfaction with IJV. The validity of the performance measures is evaluated by means of tests that assess content validity, reliability, and convergent and discriminant validity. The findings reveal that all proposed indicators are valid measures of IJV performance and that they correspond to different dimensions of performance. This research is expected to trigger further work on developing a multidimensional performance measure for IJVs in construction. In addition, the findings can help practitioners reflect on how they operate and measure the success of their IJVs. DOI: 10.1061/(ASCE)CO.1943-7862.0000314. (c) 2011 American Society of Civil Engineers.
The construction industry is vertically fragmented because of the inherent nature of construction projects, which require planning, design, letting, construction, and operation in distinct phases (Fellows and Liu, 2012; Fong and Lung, 2007). The construction industry is also horizontally fragmented \nbecause of the general tendency of participants to work independently in all phases of the project (Fellows and Liu, 2012; Saram and Ahmed, 2001). Given the increasing number of construction projects in the current global environment, geographical fragmentation is caused by project participants \nthat are frequently geographically separated. The construction industry is also temporally fragmented, as the phases of construction projects diverge over an estimated time period (Luck, 1996). According to Evbuomwan and Anumba (1998), the fragmentation in the industry results in costly engineering changes and design iterations, time and cost increases, poor communication between project participants, neglect of the application of sustainability principles throughout the life cycle of the building, and inadequate coordination and integration of the various participants. The root cause of much of these problems encountered in the management of building projects can be traced back to the design phase.
Paul Watson and Tim Howarth, Spon Press, London, 2011 321pp., ISBN 978 0 415 56911 8, £29.99 (pb) The first chapter of this book starts out with a comprehensive discussion of the various definition...
The construction industry is one of the most male dominated industries around the world, not only when it comes to workers, but also as regards managers. Only 5% of the managers in the Swedish construction industry are women. The managerial competencies of individuals working as managers in the Swedish construction industry are researched to get a clearer understanding of the situation, and to investigate if this lack of balance between male and female managers has to do with differences in managerial competence. The management development questionnaire provided by Human Resource Development Press was sent to 143 managers in the Swedish construction industry and 112 respondents (44 women and 68 men) assessed themselves in 20 competencies, resulting in a response rate of 78%. The Mann-Whitney U test showed that female and male managers possess equal managerial competencies in 17 of the 20 competencies. Male managers rated themselves as having better managerial competency than females in two of the 20 competencies, namely ‘resilience’ and ‘decision making’. Female managers rated themselves as having better managerial competency than males in ‘sensitivity’, which follows the social norm of what is expected of a woman. It was also found that both groups scored high in decision making, reflecting traditional virtues of construction managers as decisive and active. The most important result is not the differences but the many similarities between women and men working as managers in the construction industry. Thus, it is concluded that female managers are as competent as male managers in the Swedish construction industry.
Degisen sosyal, ekonomik ve kulturel etmenler, gayrimenkul olarak konut alim karar tercihlerini etkilemektedir. Konut alicilarinin ulke, bolge ve yorelerin dinamiklerine gore degiskenlik gosteren tercihleri, konut projelerinin ozelliklerini ve akimlarini dogrudan etkilemektedir. Ekonomik durum ve yikici depremler, son on yilda Istanbul’daki konut proje gelistirme yaklasimlarini ve alici kararlarini yeniden sekillendirmistir. Degisik mimari ozelliklere, sosyal tesislere sahip, cesitli tasarim ve uygulama niteliklerini karsilayan projeler ilgi gormekte ve tercih edilmektedir. Bu calismada, yerlesmek uzere alim gerceklestiren potansiyel konut alicilarinin tercih olcutlerinin tespit edilmesi ve siralanmasi amaclanmistir. Cozumleme calismasi, Istanbul’daki konut projelerinin cogunluguna imza atan buyuk konut uretim firmalarinin bakis acisindan gerceklestirilmistir. Bu amacla, gerek yazin taramasi, gerekse de bolgede uygulama yapan profesyonellerle yapilan gorusmelerde elde edilen bilgilere Analitik Hiyerarsi Yontemi (AHY) uygulanmis, konut uretim firmalarinin bakis acisindan konut alicilarinin tercihleri dokuz kategoride ele alinmistir. Calismalar sonucu, bu etkenlerin, firmalarin satis ve pazarlama politikalari, fiyat seviyesi ve odeme kosullari, sosyal etkenler, mimari ozellikler, konum ve ulasim gibi ozellikler sebebiyle firmadan firmaya cesitlilik gosterdigi saptanmistir. Bolge ozellikleri ve gerceklerinin yapilan analitik calismayla degerlendirmesi ve hem konut alicilarina, hem de konut ureticilerine yansitilmasi bu calismanin temel amacidir.
The construction industry possesses characteristics of the production and service industries. This uniqueness requires marketing practices tailored specifically to match the construction market. A questionnaire survey of 65 U.S. contractors was conducted to determine the extent to which they are implementing a modified marketing mix theory that is compatible with the construction industry. The modified marketing mix theory recommends that contractors confront marketing from five perspectives, known as the five P's of marketing: product, price, promotion, place, and people. This study showed that the five P's of marketing are used by U.S. contractors in this decreasing order: product, price, place, promotion, and people. According to the survey results, U.S. contractors allocate about 1.5% of their annual revenue to marketing, but they may be spending more than they report. There seem to be only few differences between contractors that negotiate their contracts versus contractors who competitively bid their contracts, larger versus smaller companies, and contractors with a higher success rate in getting new contract awards versus contractors with a lower success rate.
<p>The line-of-balance ~LOB! method of scheduling is well suited to projects that are composed of activities of a linear and repetitive nature. The objective of this study is to set down the basic principles that can be used in the development of a computerized LOB scheduling system that overcomes the problems associated with existing systems and creates solutions to problems encountered in the implementation of repetitive-unit construction. The challenges associated with LOB scheduling include developing an algorithm that handles project acceleration efficiently and accurately, recognizing time and space dependencies, calculating LOB quantities, dealing with resource and milestone constraints, incorporating the occasional nonlinear and discrete activities, defining a radically new concept of criticalness, including the effect of the learning curve, developing an optimal strategy to reduce project duration by increasing the rate of production of selected activities, performing cost optimization, and improving the visual presentation of LOB diagrams.</p>
