An approach for optimizing pavement design–redesign parameters in PPP projects

Modeling the elasticity modulus of unbound granular pavement materials has attracted significant research interest because of its importance in pavement design particularly in PPP/BOT projects. These efforts have been hampered by three factors: (i) inability to capture the correlations between the asphalt and granular layers and the subgrade, (ii) inadequate modeling of the effects of external factors on the elasticity modulus of unbound materials, and (iii) widespread use of linear statistical relationships to model a complex and non-linear phenomenon. In this paper genetically optimized neural networks and falling weight deflectometer (FWD) back-analysis results from a newly constructed BOT project in Athens, Greece, are employed in order to evaluate pavement section design parameters. It is shown that parameter values adopted during design do not co-inside with those observed from the back-analysis studies. Further, the results indicate that the relative estimation error for the modulus of elasticity of the unbound material does not exceed 25%, while the correlation between actual and predicted values is 86%, both suggesting that the proposed approach models the physical phenomenon adequately, a finding with important practical implications particularly in PPP projects.     

A review of studies on Public–Private Partnership projects in the construction industry

Public–Private Partnership (PPP) in construction is gaining in popularity. Although papers published in major journals have documented real cases of PPP projects, there appears to be a lack of systematically summarizing what they have already provided. Consequently, this paper reviewed PPP studies published in the six top journals in the construction field. The objectives are to compare and contrast the findings of the studies so as to provide insights for directing further PPP research and improving the existing practices of PPP projects. To achieve the review objectives, studies were first classified as either empirical or non-empirical. Empirical studies were further grouped under three themes: risks, relationships, and financing. Non-empirical studies were grouped under five themes: financing, project success factors, risks, and concession period. Suggestions for further research are risks, financing, contractual agreements, development of PPP models, concession periods, and strategies in choosing the right type of PPP.     

Where does the money go? Economic flow analysis of construction projects

A new approach is introduced for analysing the economic flows in a construction project that will complement the existing methods. The main focus of the new method is to trace the flow of costs in the project and identify their spatial characteristics as well as who are the final recipients. This type of analysis highlights the flow of costs of the specific project in the local economy. It can be used for decision-making purposes from the project-commissioning party. Costs were divided into six categories, namely: labour, materials, energy, office overheads, taxes and personnel, and into two levels: local and national. Three case studies of stone and reinforced concrete structures were selected and analysed to test the application of this method. The case studies showed that this method and the representation by a Sankey diagram can provide useful insights regarding both the spatialized distribution of the cost of a project and the economic flows going to direct labour versus overhead and taxes. For future projects, local authorities or developers can select the most economically suitable strategy maximizing the income of the local community.     

Interpersonal trust and inter‐firm trust in construction projects

Working relationships are important in effecting project performance and cooperation is believed to be a behavioural consequence of trust. Trust, being a quality of relationships, involves people interacting at interpersonal and inter‐firm levels. This is investigated through 10 partnering and non‐partnering projects, using a validated trust scale. A case study approach is used to collect qualitative data through a quantitative approach to help understand the concept of trust. Data were collected from clients, contractors, consultants and subcontractors. Clients and contractors have a tendency to trust individuals whereas contractors and subcontractors have a tendency to trust firms. Inter‐firm trust is better understood than interpersonal trust; but both are associated with keeping commitments and demonstrating cooperation, even though interpersonal trust is considered more important. Partnering does not necessarily exhibit more trust than non‐partnering projects whereas clients and contractors have different emphasis on interpersonal and inter‐firm trust. Therefore, to promote trusting relationships in multi‐parties is to fulfil not only the technological and economical goals, but also the moral and social goals as expressed in people relationships such that a socially safe working place can be created. For this reason, middle managers need to know about trust because they face more relationship problems than others.     

EnergyPlus model-based predictive control within design–build–operate energy information modelling infrastructure

This study proposes a design–build–operate energy information modelling (DBO-EIM) infrastructure to allow users to deploy the design-stage building energy model for model predictive control (MPC) system in the building operation. A newly constructed office building is studied as a test bed. An EnergyPlus model-based predictive control (EPMPC) system is designed and simulated in the Matlab/Simulink environment within the DBO-EIM infrastructure. EPMPC aims at minimizing heating, ventilation, and air conditioning energy consumption while maintaining occupant thermal comfort. Compared to the baseline rule-based control system, EPMPC demonstrates a 28.9% energy reduction in one-week simulation in the heating season and 2.7% energy reduction in one-week simulation in the cooling season. The comfort constraint is met during more than 90% of the simulated hours. The study demonstrates one significant contribution of the DBO-EIM infrastructure that a design-stage EnergyPlus model can be integrated in an MPC system and the preliminary simulation results are satisfactory.     

Input–output analysis of the Chinese construction sector

The construction sector has played a key role in the Chinese economy, which has been experiencing a rapid growth for the past two decades. This development and growth are reviewed in a framework of input–output analysis. The national input–output table (IO table) was used to study the current input–output profile of the Chinese construction sector and the relationship between the construction sector and other sectors. The pull and push effect of the Chinese construction industry to the whole national economy has been estimated. It shows that the pull effect is much larger than the push effect. Furthermore, through the analysis of a series of four IO tables spanning over the last 10 years, it reveals that the pull and push effect of the Chinese construction industry are both getting larger and larger. This means the Chinese construction industry is becoming mature and is in great transition.     

An input–output analysis of Thailand's construction sector

Three input–output (IO) tables compiled between 1995 and 2000 were used to examine the significance of the construction sector and its relationships with other sectors of the Thai economy. The pull and push effect of the Thai construction sector to the national economy indicated that the former is much larger than the latter. Additionally, the relatively high output multipliers and backward linkage indicators showed that the construction sector had the potential to trigger off production in many economic sectors linked to it. An aggregated sectoral analysis revealed the high dependence of construction on manufacturing followed by services. The findings also suggest that the trends of the profile of inputs and outputs are correlated to the economic conditions in Thailand at the time the IO tables were compiled. Finally, the results of employment analysis showed that although the share of construction sector in direct employment generation may not be very large, its economic importance lies in its direct and indirect contribution to employment through strong backward linkage effects. Consequently, when its backward linkages and output multiplier are considered together with the employment opportunities latent within it, then the construction sector could be a major contributor to the economic growth of Thailand.     

Emotional intelligence and British expatriates’ cross-cultural adjustment in international construction projects

Today’s internationalized business demands global mindset, intercultural sensitivity and the ability to skilfully negotiate through cross-cultural interactions. Therefore, the overall aim was to investigate the influence of emotional intelligence (EI) on cross-cultural adjustment (CCA) of British expatriates working on International Architectural, Engineering and Construction assignments in Sub-Saharan Africa, China, Middle East and Indian Sub-Continent. Specifically, the causal relationship between EI and three facets of CCA i.e. work, general and interaction adjustment was explored. A sequential exploratory mixed methods design was adopted. These include extensive review of existing literature, eighteen unstructured interviews, and questionnaire survey of 191 British expatriates operating in 29 different countries from the four regions under investigation. Structural equation modelling was used to assess the causal relationship between EI and CCA. Results show that EI accounted for 91, 64 and 24% of the variance in work, interaction and general adjustment respectively. Overall, the model was able to explain 60% variance in CCA, suggesting that EI competencies play a huge role in facilitating an expatriate understand and adapt to host country culture. The findings would help decision-makers (HR managers) during expatriate selection process, in understanding that along with technical skills, it is the emotional competencies that are crucial in assisting expatriates adjust to foreign way of life.     

Can community design build trust? A comparative study of design factors in Boise,Idaho neighborhoods

Finding ways to increase trust may be one mechanism to overcome the alleged negative consequences of urban sprawl for neighborhoods. This study explores two relationships with community design and trust. First, is one benefit of some of the underlying concepts of New Urbanism design that they build trust? Second, can these design concepts overcome one undesirable feature of cities: the deleterious effect of income inequality on trust? This study uses survey data collected from 34 city of Boise neighborhoods and 2000 US census data aggregated to the neighborhood level to examine the effects of street design, sidewalks and open space on building trust and moderating the effect of income inequality on trust. The study finds that cul-de-sac designed streets, sidewalks and parks or open space increase trust. There is no evidence that design features actually moderate the effects of income inequality on trust. The findings suggest that local governments can influence the quality of life for residents in their communities through neighborhood design even if municipalities cannot use design to moderate the effects of income equality on trust.     

Why do individuals engage in collective actions against major construction projects? —An empirical analysis based on Chinese data

Collective actions against major construction projects are becoming common because of the public’s increasing civil rights awareness and environmental consciousness. Thus, it is important to explore the critical factors responsible for collective actions against major construction projects. This study initially developed 25 indicators inducing collective actions based on a comprehensive literature review. An empirical study with 127 samples was conducted using questionnaire surveys and semi-structured interviews from projects located in Central China. Furthermore, ranking analysis and factor analyses were implemented to conclude that collective actions in major construction projects can be explained by a six-dimension critical factor system: benefits to the public, characteristics of project performers, layout of projects, living quality of the public, perceptions of the public, and influence from the authority. This study contributes to government administration for collective actions against major construction projects and serves as a useful reference for further studies of this type.     

Automated trade‐off between time and cost in planning repetitive construction projects

An automated model is developed to support the optimization of the planning and scheduling of repetitive construction projects. The model provides the capability of optimizing two important objectives commonly sought in scheduling repetitive construction projects: minimizing project duration; and minimizing project cost. The model performs this multi‐objective optimization using a genetic algorithm approach. The output of the model is a set of optimal solutions that represent the trade‐off between time and cost in planning repetitive construction projects. Furthermore, the model can be utilized to find a single scheduling solution that provides the minimum overall project cost by simply adding project indirect cost to the obtained project direct cost for each of the obtained scheduling solutions on the Pareto optimal curve. Other important time‐related costs are also considered in the model including: early completion incentives, late completion penalties and lane rental costs. Providing the planners of repetitive construction projects with an automated set of optimal time–cost trade‐off solutions should contribute to cost‐effective and speedy delivery of this type of construction project. An application example is analysed to illustrate the use of the model and demonstrate its capabilities in generating optimal trade‐off solutions between minimizing the project time and cost for repetitive construction projects.     

Input–output analysis of Irish construction sector greenhouse gas emissions

Ireland is committed to limiting its greenhouse gas (GHG) emissions to 113% of 1990 levels over the period 2008–12 and to 84% of 2005 levels by 2020 under the Kyoto Agreement and the EU's 2020 target by 2020 respectively. National policies have targeted many industry sectors but have failed to directly tackle GHG emissions associated with construction activity. This paper estimates energy and GHG emissions intensities of the Irish construction sector and subsectors and estimates its contribution to Irish national emissions. This information is used to identify and assess the impacts of policy measures which would result in a reduction in emissions from the sector in a cost-effective manner. Energy and emissions intensities are estimated using input–output analysis techniques applied to Irish construction sector.     

Desirability rating analysis for debt financing of public–private partnership road projects

Public–private partnership (PPP) road projects are highly leveraged capital‐intensive projects. Lenders, which provide the major portion of financing in the form of debt instruments, undertake loan approval processes to examine the various aspects of the projects that could influence the debt servicing capability while making credit decisions. In view of this, project sponsors could also assess beforehand how desirable is the project from the debt financing perspective in order to facilitate timely arrangement of debt financing and avoid funding problems. The Desirability Rating Analytical Tool (DRAT) has been developed in order to enable the project sponsor to assess how desirable the project is from a debt financing perspective. DRAT uses the aggregation operator Choquet fuzzy integral to aggregate the information relating to the various aspects of PPP road projects that lenders take into account while making credit decisions. The application of DRAT is illustrated with an example of a PPP road project from a National Highways Development Programme undertaken by the National Highway Authority of India, Government of India. DRAT expressed the result of the information aggregation in the form of a desirability rating profile indicating the degrees of membership to different levels of desirability. The desirability rating profiles of the project provide valuable information for decision making and can help in formulating strategies on improving the performance of the project where it is not performing satisfactorily.     

Using the MD CAD model to develop the time–cost integrated schedule for construction projects

Time and cost are two critical factors determining the success of a construction project. However, it is still a daunting task for project planners to develop a time–cost integrated schedule due to the tremendous amount of information that need to be processed. Various research efforts have been made to develop model-based systems to facilitate information processing and integrate time and cost throughout the project life cycle. However, the results of the previous studies are not comprehensive enough to fulfill the requirements of project management. This paper presents a scheduling system that applies Multi-Dimensional (MD) CAD model, Object Sequencing Matrix (OSM), and genetic algorithms (GAs) to generate the time–cost integrated schedule for the construction project. A computer implementation called MD CAD model-based Project Scheduling System (MD_PSS) is also developed to verify the feasibility of the proposed approach.     

Exploring the dynamics of the Turkish construction industry using input–output analysis

Construction is commonly regarded as an important industry in economic policy making owing to its strong interactions with other sectors in the economy. Using six national input–output (IO) tables compiled to date and economic data for the period between 1969 and 2006, the behaviour of the Turkish construction sector and its relationships to investment, income and to other sectors in the economy are examined. Analysis reveals that the construction industry is losing its propulsive role and that it tends to exaggerate the fluctuations of the economy. The examination of lead and lag times between changes in GNP, construction activity and investments show that public sector spending cuts, in particular, have significant effects on the amplitude and the timing of slumps of the industry. The analysis of linkage indicators indicates that for the whole period under consideration the construction industry has high linkages with only one other industry. Thus the ‘leading’ role it plays in the economy is questioned.     

Cost–safety trade-off in unequal-area construction site layout planning

Cost and safety are two key elements when designing a good construction site layout planning (CSLP). Previous research works always considered CSLP from the aspect of reducing cost and treated SCLP as a single objective optimization problem. In the paper, CSLP was designed by a multi-objective optimization (MOO) model using modified Pareto-based ant colony optimization (ACO) algorithm, which could find a Pareto solution (trade-off layout) to fulfill the requirement of reducing cost and improve the site safety level simultaneously. Furthermore, in order to apply MOO model to solve unequal-area problem, the random grids-recognition strategy was employed in the proposed MOO model to solve the unequal-area site layout problems without increasing the computational complexities. A case study of a residential building project is used to validate the proposed MOO model and the results are very positive.     

Recent advances in fire–structure analysis

One of the recommendations of the National Construction Safety Team (NCST) for the Federal Building and Fire Safety Investigation of the World Trade Center Disaster [NIST NCSTAR 1 Final report on the collapse of the World Trade Center Towers. NCST for the Federal Building and Fire Safety Investigation of the World Trade Center Disaster, National Institute of Standards and Technology, Gaithersburg, MD, September 2005] is to enhance the capability of available computational software to predict the effects of fires in buildings, for use in the design of fire protection systems and the analysis of building response to fires. Following this recommendation, this paper presents two new interfaces in fire–thermal–structural analysis. The first interface uses adiabatic surface temperatures to provide an efficient way of transferring thermal results from a fire simulation to a thermal analysis. It assigns these temperatures to surface elements of structural members based on proximity and directionality. The second interface allows the transfer of temperature results from a thermal analysis modeled with solid elements to a structural analysis modeled with beams and shells. The interface also allows the reverse, namely the geometric updating of the thermal model with deflections and strains obtained from the structural analysis. This last step is particularly useful in intense fires of long duration, where significant deflections and strains could cause damage to insulation and displace the structure to a different thermal regime. The procedures can be used for a variety of fire simulation, thermal, and structural analysis software.     

The rhythms of project life: a longitudinal analysis of work hours and work–life experiences in construction

A diary data collection method was used to collect data from project‐based construction workers in a large civil engineering construction project in Melbourne, Australia. Data capturing the number of hours worked, satisfaction with work–life balance and capacity to complete required tasks at work and at home were collected for 21 consecutive weeks. A strong correlation was found between hours worked each week and participants’ work–life experiences. Data were subjected to time series modelling procedures and weekly work hours were found to significantly predict participants’ capacity to complete tasks at work and at home, but not their satisfaction with work–life balance. The impact of work leading up to a major project milestone was found to increase the predictive capacity of the time series models, indicating that project events have a significant impact upon the work–life experiences of project‐based workers. The period of intense work prior to the milestone (the opening of a new ramp on to an operating freeway) contributed significantly to an immediate reduction in capacity to complete tasks at home. Further time series modelling revealed that recovery opportunities associated with workers taking a short, temporary break from work can also contribute to improved work–life balance. It is proposed that construction organizations use the naturally fluctuating workloads implicit in project work to ‘build’ recovery opportunities into project schedules.     

Fuzzy-multi-objective particle swarm optimization for time–cost–quality tradeoff in construction

The time–cost–quality tradeoff (TCQT) problem is to decide an optimal combination of construction methods with the objective of minimizing cost and time while maximizing quality. Searching for such an optimal combination of construction methods needs to evaluate the total cost, time and quality of the project. These performances, especially the quality, may be collected and recorded in terms of imprecise or vague data rather than precise numbers. This paper presents a fuzzy-multi-objective particle swarm optimization to solve the fuzzy TCQT problem. The time, cost and quality are described by fuzzy numbers and a fuzzy multi-attribute utility methodology incorporated with constrained fuzzy arithmetic operations is adopted to evaluate the selected construction methods. The particle swarm optimization is applied to search for the TCQT solutions by incorporating the fuzzy multi-attribute utility methodology. The proposed methodology is implemented and justified through computational analyses. The study is expected to provide an alternative methodology for solving the time–cost–quality tradeoff problem.