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Cost performance in the construction industry is important to enhance industry standard and grow a country's economy. This paper examines the key factors affecting cost performance in Thai construction projects, specifically at the pre-construction and construction phases. A questionnaire survey is used to gather data for the exploratory factor analysis (EFA) and structural equation modelling (SEM) analysis used in this study. The EFA technique extracted the key factors affecting construction cost, while the SEM revealed the interactions and causal relationships between those key factors. The EFA results confirm seven key factors: three at the pre-construction phase: lack of coordination, design management, and unclear client requirements; and four at the construction phase, including site management, resources, labour capability and contract-related. The SEM results confirm strong relationships, directly and indirectly, between the three key factors at the pre-construction phase. Good coordination between stakeholders result in less design errors and clear client requirements. The influences that the three factors at the pre-construction phase have on the four factors at the construction phase are also supported. The result highlights that unclear client requirements cause poor site management and cost overrun, which may lead to breach of contracts. Construction companies can use this study results to better plan for cost improvement by focusing on the identified pre-construction factors, as they could lead to good cost management during the construction phase.

Purpose Offsite construction approaches and methodologies have been proffered a potential solution for controlling “traditional” projects, especially where high levels of complexity and uncertainty exist. Given this, locations such as Western Australia (WA), where there are unique housing provision challenges, offsite construction method was considered a potential solution for not only addressing the complexity/uncertainty challenges but also alleviating the housing shortage. However, whilst acknowledging the benefits of offsite construction, recognition was also noted on perceived barriers to its implementation, primarily relating to cost uncertainty. This recognition is exacerbated by very limited offsite construction cost data and information available in the public domain. In response to this, this paper sims to provide detailed cost analysis of three offsite construction projects in WA. Design/methodology/approach To hold parameters constant and facilitate cross-case comparative analysis, data were collected from three embedded case studies from three residential housing projects in WA. These projects represent the most contemporary implementation of offsite in WA; where two were completed in 2016/2017 and the third project was still ongoing during the data collection of this research. The research methodological approach and accompanying data analysis component engaged a variety of techniques, which was supported by archival study of project data and evidence gathered from the offsite construction provider. Findings Core findings revealed three emerging themes from residential offsite construction projects pertinent to cost. Specifically, the overall cost of delivering residential housing project with offsite construction techniques, the cost variability of offsite construction residential housing projects as impacted by uncertainties and the cash flow of residential offsite construction projects based on the payment term. These three major cost drivers are elucidated in this paper. Originality/value This research presents new cost insights to complement the wider adoption of offsite construction techniques. It presents additional information to address the limited cost data and information of offsite construction projects available in the public domain particularly for residential housing projects (within the bounded context of WA). It also highlights the further stages needed to enhance data validity, cognisant of universal generalisability and repeatability, market maturity and stakeholder supply chains.

Compared with AC distribution networks, DC distribution networks reduce the utilisation of power converters, power loss, and construction cost. In DC distribution network, the high-frequency modular multilevel DC converter (MDCC), which connects the low-voltage DC link with medium- or high-voltage DC links, becomes a practical equipment to realise the bus connection, voltage conversion, and electrical isolation. Especially, high-frequency link (HFL) modulation plays an important role in converter performance. The square-wave (SW) modulation obtains better power transfer capability and higher DC voltage utilisation. However, the SW modulation leads to a large dv/dt stress upon HFL transformer. The sinusoidal, triangle and quasi-square-wave (QSW) modulations reduce dv/dt and harmonics significantly. However, the power transfer capability and DC voltage utilisation are also reduced. To address dv/dt stress problem, ensure high DC-voltage utilisation and maintain a strong power transfer capability simultaneously, a hybrid-wave modulation strategy, which composed of QSW and SW modulation, is proposed for MDCC. The experimental results verify the analysis and proposed scheme.

Managing risk in construction projects has proven to be a challenge for many project managers and stakeholders involved in projects. The lack of a systematic approach and standardized proce...

The forecast of the most probable cost of an intervention in the construction or engineering field developed through a bill of quantities is one of the most critical operations of economic and technical planning [1, 2, 3, 4]. Regarding to public works, the recent legislation (Legislative Decree n. 50/2016) has introduced some changes relating the evaluation of costs; the paragraph 7 of article n. 23—which defines the three levels and contents of the design—establishes that the definitive project, in addition to the complete identification of the work and the elements necessary for the authorizations and approvals, must contain “the definitive quantification of the expenditure limit and the related time schedule, through the use, where existing, of the price lists prepared by the regions and autonomous provinces territorially competent”. The reference to regional prices for the estimate of the economic amount has the objective of establishing fair prices for the various operators (designers, construction companies etc.), at least within a territorial area representative of the economic and technological characteristics of the building sector. In many territorial areas, this entails the transition from provincial prices list to regional prices list, with evident difficulties especially for those areas characterized by specific productive and economic realities. In 2018 the Lombardy Region does not yet have a regional price list and only the provincial price lists (published by the local Chambers of Commerce) or that published by the Municipality of Milan were utilized. Precisely in relation to the new requests introduced by national legislation relating to the use of regional price lists for the estimation of public works, this contribution aims to analyze what are the differences in unitary prices for some of building works and verify the possibility of determining “concordance” indices to be considered in the elaboration of a regional price list able to take into account the different functions of formation of the costs (and therefore of the building works prices) of the workings between different provincial areas.

The aim of the present paper is to investigate the literature on the issues of construction costs in building production and urban development in order to identify the most relevant trends and describe the research context. In particular, a bibliometric analysis was carried out through one of the most acknowledged bibliometric databases, Scopus. Due to the great number of documents related to this topic, the literature review was conducted at three different levels: the first one investigates in a wider manner the cost value, the second one analyses the costs in building production and infrastructure, whereas the third one focuses on the evaluation approaches and new trends emerging from the literature. This study has allowed an advance in the comprehension of the main relevant issues related to this topic and an in-depth understanding of the role of evaluation methods as an instrument to synthesize the full range of aspects involved in the cost and in the project life-cycle. The increasing importance of topics like Building Information Modeling (BIM), Life Cycle Assessment (LCA) or Multicriteria analysis shows clearly a transition of the research to a sustainable view of the production operations and to a life cycle perspective of the projects.

Construction accidents can have major social, financial, reputational and legal implications. Hence, it is to be expected that safety is often presented as a key priority for construction organisations. However, existing evidence suggests that within the construction industry, safety often loses the battle when a trade-off is required with project cost. Improved understanding of the manifestations of the cost and safety interaction are needed. A three-year longitudinal study afforded the opportunity to investigate the safety implications of sub-economic bids on a large infrastructure project in the UK. While low-bidding to win tenders is not new, this paper presents empirical evidence of the consequential safety risk implications of such bidding at the project delivery stage. Faced with a perverse form of the tender ‘Winner’s Curse’ where the successful bid is frequently the lowest, cost-saving strategies are often implemented to recoup lost pricing margins. Our investigation revealed several instances of consequentially elevated safety risks, through cheaper and poor-quality equipment, machinery and temporary structures. In addition, lower-paid migrant workers – who already experience a statistically greater safety risk than local workers – were employed on the project without appropriate investment in a safety management approach suitable for a multinational workforce. The study both contributes to the call to critically rethink the construction industry’s competitive bidding practices, and highlights an industry structure that creates the conditions for high safety risks and accidents.

Management of the design phase of construction projects affects the success of the projects. Generally, architects are the main actors who dominate the whole process of the building constructions. In this study, the architects’ design experiences in terms of the effect of design phase meetings on change orders in building construction projects are investigated. As a result of the study, it is concluded that there is no relationship between the frequency of meetings and requested and realized project changes in the design phase. It is also observed that, except for the architects, if the formation of the stakeholders participating in the design meetings can be varied, this can minimize the project changes and possible problems due to conflicting interests, and the participation of different groups to the design phase meetings could be a way of keeping the requests of changes in design and construction stage to a minimum., İnşaat projelerinde tasarım aşamasının yönetimi projelerin başarısını etkilemektedir. Genellikle bina inşaatlarının tasarım aşamasında mimarlar tüm sürece hâkim baş rol oyuncularıdır. Bu çalışmada, mimarların tasarım aşamasında gerçekleştirdikleri toplantıların, bina inşaat projelerinin değişiklik talimatları üzerindeki etkisi incelenmiştir. Çalışma sonucunda, toplantıların sıklığı ile tasarım aşamasında talep edilen ve gerçekleştirilen proje değişiklikleri arasında bir ilişki olmadığı sonucuna varılmıştır.Ayrıca projede yer alan mimarlar haricinde diğer paydaşların da tasarım toplantılarına katılmaları, proje değişikliklerini ve çatışan çıkarlarından kaynaklanan olası sorunları en aza indirebileceği, tasarım ve inşaat aşamasındaki değişiklik taleplerinin asgari düzeyde tutulmasına yardımcı olacağı tespit edilmiştir.

Countries around the world are making efforts to develop and introduce green building certification systems to save energy and reduce greenhouse gas emissions. As a result of these efforts, green certification systems are rapidly spreading. Consistent with this, certification systems are also being developed and research related to various technologies and regulations is ongoing. However, most research focuses on residential and commercial buildings and there is still a lack of scientific research on educational facilities. To fill the gap and support the former studies, this research statistically studies the economic effects of green certification systems on educational facilities. For this purpose, the benefits, i.g., building price and maintenance & repair costs, were examined for universities in Canada that were admitted to the Canadian Educational Institution. As shown by the results of this study, Leadership in Energy and Environmental Design (LEED)-certified buildings cost 49.9% more to build and had 25.6% lower maintenance and repair costs than non-LEED certified buildings.

The energy consumption of affordable housing industry plays a vital role in the environmental sustainability, waste generation and energy consumption. The development of sustainable housing construction methodology helps its country’s economic development and sustainable development. Wall and roof are the most significant building component in a dwelling unit. The walling materials can determine the cost of the building as well as the total life cycle cost of a dwelling unit. In this study, the total life cycle cost of a basic dwelling unit in Sri Lanka, made of mostly available walling materials such as Brick, Hollow cement block, and Cabook, the Mud concrete blocks were calculated by using energy accounting hierarchical structure. The life cycle cost incurred due to change in above-mentioned walling materials were calculated and measured. Additionally, total LCC compared and analyzed. The results show that mud concrete block is the most suitable walling material. The brick has the highest account for the embedded energy. The hollow cement block is the worse building materials in tropics and its carbon footprint is comparatively higher. Even though the brick has higher embedded energy and construction cost, in a long run brick is less expensive than hollow cement block and Cabook walling material. Concluding, mud concrete block is comparatively most sustainable walling material for building affordable housing in tropics.

This paper reports data describing development projects for new buildings according to construction costs in North-East Italy. A survey was carried out on local companies undertaking new residential development projects in two Italian regions (Veneto and Lombardy). The aim of this survey was to record new real estate construction projects, collecting both technical and socio-economic cost features. It is extremely difficult to collect such data for the Italian real estate construction sector, due to its lack of transparency, so that the novelty for the Italian scenario is the dataset itself. Another interest perspective of this survey is that socio-economic characteristics were also recorded; they are often studied in urban economics, but are usually related to property purchase prices and values, not to construction costs. The data come from an analysis of Canesi and Marella regarding the relationship between the trend of construction costs and the socio-economic conditions of the reference setting, such as the mean years of schooling of the workforce, housing market trends, and average per capita income.

Erdal, Mursel/0000-0002-9338-6162; Namli, Ersin/0000-0001-5980-9152 WOS: 000463791300006 The analysis of a construction project, regarding cost, is one of the most vital problem in planning. Due to its nature, the construction sector is an area of strong competition and estimation works are of vital importance. In recent years the Turkish Republic has started a serious urban regeneration movement in parallel to its economic development. This study is based on the drawings and quantities of 63 detached multi-story reinforced concrete housing unit projects of the Housing Development Administration (TOKI) and the Turkey Residential Building Cooperative Union (TURKKONUT). TOKI is a public company and its projects are that have been applied to 282 separate projects and are being applied to a further 266. On the other side TURKKONUT is a union of 1347 private building cooperative and have been completed 200,000 residential building. The main objective of this study is to improve the estimation accuracy of individual machine learning techniques, namely multi-layer perceptron and classification and regression trees and compares the performance of two machine learning meta-algorithms (i.e., bagging and random subspace) on a real world construction cost estimation problem. The study shows that the estimation accuracy of ensemble models are better than the models that constructed by their base learners and ensemble models may improve individual machine learning models.

This research tries to investigate, in the current condition of the Italian real estate market, the economic advantage of investing in energy retrofitting of existing buildings or in expenditure aimed at obtaining higher energy performances in the construction phase of new buildings. A cost-benefit analysis is developed referring to the construction industry entrepreneur. Firstly, the increase in value due to a different measurement of the energy performance of new buildings or newly redeveloped residential buildings is achieved through an innovative statistical approach. Energy performance is measured by taking as a reference the category of energy certification, as required by European legislation. In the estimate of the contribution, the measurement of energy performance, expressed on an ordinal scale, is treated as a categorical variable in the implementation of an iterative regression model, called the alternating least squares model. Afterwards, this contribution is compared to the cost of sustainable building, trying to define a percentage increase in cost compared to a minimum condition according to different and increasing levels of energy performance. In the developed case studies, the comparison between likely benefits and investment spending showed that the entrepreneur would have no convenience at an expense for energy retrofitting while obtaining a positive balance in the construction phase of new buildings. The financial advantage grows if the investment is aimed at achieving the best energy performance and in areas where the price level of the real estate market is lower. The finding can be used as a guide for construction industry investors to make decisions in energy-efficient residential buildings production or transformation.

This study deals with small investors’ demands on thermal insulation systems when choosing the most suitable solution for a family house. By 2050, seventy percent of current buildings, including residential buildings, are still expected to be in operation. To reach carbon neutrality, it is necessary to reduce operational energy consumption and thus reduce the related cost of building operations and the cost of the life cycle of buildings. One solution is to adapt envelopes of buildings by proper insulation solutions. To choose an optimal thermal insulation system that will reduce energy consumption of building, it is necessary to consider the environmental cost of insulation materials in addition to the construction cost of the materials. The environmental cost of a material depends on the carbon footprint from the initial origin of the material. This study presents the results of a multi-criteria decision-making analysis, where five different contractors set the evaluation criteria for selection of the optimal thermal insulation system. In their decision-making, they involved the requirements of small investors. The most common requirements were selected: the construction cost, the construction time (represented by the total man-hours), the thermal conductivity coefficient, the diffusion resistance factor, and the reaction to fire. The confidences of the criteria were then determined with the help of the pairwise comparison method. This was followed by multi-criteria decision-making using the method of index coefficients, also known as the method of basic variant. The multi-criteria decision-making included thermal insulation systems based on polystyrene, mineral wool, thermal insulation plaster, and aerogels’ nanotechnology. As a result, it was concluded that, currently, in Slovakia, small investors emphasize the cost of material and the coefficient of thermal conductivity and they do not care as much about the carbon footprint of the material manufacturing, the importance of which is mentioned in this study.

In the last decade, displacement-based seismic design procedures have been recognised to be effective alternatives to force-based design (FBD) methods. Indeed, displacement based design (DBD) may allow the structural engineer to get more realistic predictions of local and global deformations of the structure, and hence damage, under design earthquakes. This facilitates the achievement of performance objectives and loss mitigation in the lifetime of the structure. Nonetheless, DBD needs further investigation for some structural types such as masonry buildings. In this paper, a direct displacement based design (DDBD) procedure for unreinforced masonry (URM) buildings is presented and critically compared to FBD. The procedure is proposed for box-type URM buildings with reinforced concrete slabs, bond beams and lintels above openings, which have shown acceptable seismic performance in severe earthquakes preventing out-of-plane failure modes. Seismic design of a three storey brick masonry building in a high seismicity region is discussed as a case study. The effects of ordinary and near-field design earthquakes, as well as load combinations and accidental eccentricity prescribed by current codes, were investigated. Finally, design solutions provided by FBD and DDBD were optimised and their construction costs were estimated. It was found that, particularly at small epicentral distances, neglecting the combination of horizontal seismic actions and accidental eccentricity may induce significant underestimation and an ideally more uniform distribution of strength demands on URM walls. In addition, construction costs resulting from DDBD may be significantly lower than those related to code based FBD procedures.

Shaping the methodological basis of professional construction management it is possible tospeak about a new direction in the development of the construction pricing – the development of cost management system in construction (cost engineering in construction) integrating the assessment of investment costs, estimated pricing, contract pricing, evaluation of the actual construction costs, and enabling toconnect and manage the aforementioned processes. At the same time the concept of cost engineering in construction fixes the engineering, technical and technological basis of all processes directly or indirectly related to the definition of construction costs. The article presents the authors’considerations on the creation and implementation of cost engineering systems in construction at thenational, territorial and corporate levels.

Refurbishing buildings helps reduce waste, and limiting the amount of embodied carbon in buildings helps minimize the damaging impacts of climate change through lower CO2 emissions. The analysis of embodied carbon is based on the concept of life cycle assessment (LCA). LCA is a systematic tool to evaluate the environmental impacts of a product, technology, or service through all stages of its life cycle. This study investigates the embodied carbon footprint of both new-build and refurbished buildings to determine the embodied carbon profile and its relationship to both embodied energy and construction cost. It recognizes that changes in the fuel mix for electricity generation play an important role in embodied carbon impacts in different countries. The empirical findings for Hong Kong suggest that mean embodied carbon for refurbished buildings is 33&ndash, 39% lower than new-build projects, and the cost for refurbished buildings is 22&ndash, 50% lower than new-build projects (per square meter of floor area). Embodied carbon ranges from 645&ndash, 1059 kgCO2e/m2 for new-build and 294&ndash, 655 kgCO2e/m2 for refurbished projects, which is in keeping with other studies outside Hong Kong. However, values of embodied carbon and cost for refurbished projects in this study have a higher coefficient of variation than their new-build counterparts. It is argued that it is preferable to estimate embodied energy and then convert to embodied carbon (rather than estimate embodied carbon directly), as carbon is both time and location specific. A very strong linear relationship is also observed between embodied energy and construction cost that can be used to predict the former, given the latter. This study provides a framework whereby comparisons can be made between new-build and refurbished projects on the basis of embodied carbon and related construction cost differentials into the future, helping to make informed decisions about which strategy to pursue.

This study aims to implement the linear regression method to generate a linear regression equation that can be used in the study of EIA (Environmental Impact Assessment) to predict the cost of WWTP (Wastewater Treatment Plant) of the data wastewater flowrate with case study of ten malls in Surabaya city.Some previous researchers have produced data on a linear regression WWTP construction costs and wastewater flowrate.In the EIA study in Indonesia, management and monitoring costs include costs of construction, operation and maintenance costs, and monitoring costs.Therefore, these costs will be calculated for WWTP of malls with unit prices prevailing in Surabaya city. The methodology of the study consists of the calculation of the construction cost, the calculation of operation and maintenance cost, the calculation of monitoring cost, and the process of making a linear regression curve. The result showed that from the ten malls, the smallest flowrate was 0.88 l/sec and 6.72 l/sec the largest, while the calculation of the cost was gained at the least as 577x10 6 IDR and the biggest cost was 2163 x10 6 IDR. The linear regression curve between the flow rate WWTP (as independentvariables in the X axis) and the total cost WWTP (as dependent variables in the Y-axis) has produced a regression equation of Y = 358 + 271X. The result of the linear regression equation can be used directly by the EIA committee in Surabaya city and activityinitiator of mall to predict the cost of WWTP quickly and to decide the environmental feasibility of the mall.

The objective of this research was to develop a model to estimate future freeway pavement construction costs in Henan Province, China. A comprehensive set of factors contributing to the cost of freeway pavement construction were included in the model formulation. These factors comprehensively reflect the characteristics of region and topography and altitude variation, the cost of labour, material, and equipment, and time-related variables such as index numbers of labour prices, material prices and equipment prices. An Artificial Neural Network model using the Back-Propagation learning algorithm was developed to estimate the cost of freeway pavement construction. A total of 88 valid freeway cases were obtained from freeway construction projects let by the Henan Transportation Department during the period 1994−2007. Data from a random selection of 81 freeway cases were used to train the Neural Network model and the remaining data were used to test the performance of the Neural Network model. The tested model was used to predict freeway pavement construction costs in 2010 based on predictions of input values. In addition, this paper provides a suggested correction for the prediction of the value for the future freeway pavement construction costs. Since the change in future freeway pavement construction cost is affected by many factors, the predictions obtained by the proposed method, and therefore the model, will need to be tested once actual data are obtained.

The objective of this report is to provide a methodology for examining bids and evaluating the performance of engineer’s estimates in capturing the true cost of projects. This study reviews the cost development for transportation projects in addition to two sources of uncertainties in a cost estimate, including modeling errors and inherent variability. Sample projects are highway maintenance projects with a similar scope of the work, size, and schedule. Statistical analysis of engineering estimates and bids examines the adaptability of statistical models for sample projects. Further, the variation of engineering cost estimates from inception to implementation has been presented and discussed for selected projects. Moreover, the applicability of extreme values theory is assessed for available data. The results indicate that the performance of engineer’s estimate is best evaluated based on trimmed average of bids, excluding discordant bids.

When the external measurements of a building are fixed, an increase in external wall thickness caused by additional insulation, for example, will lead to loss of saleable floor area. This issue has to be taken into account in the evaluation of investment profitability. This paper examines how technologies used in energy-efficient residential building construction affect the available saleable floor area and how this impacts profitability of investment. Using a modeled building and an analysis of the average construction cost, we assessed losses and gains of saleable floor area in energy-efficient buildings. The analysis shows that the impact of potential losses or gains of saleable floor area should be taken into account when comparing investment alternatives: building energy-efficient green dwellings or building conventional ones. The results indicate that constructing energy-efficient buildings and introducing very energy-efficient technologies may be energy- and cost-effective even compared with conventional buildings. Employing new products in energy-efficient construction allows benefit to be drawn from lower energy consumption during the life cycle of the building, but also from the increase in saleable floor area.

As a part of the project “Total System of Zero-emission Coal-fired Power Generation Project” led by New Energy and Industrial Technology Development Organization (NEDO), we have conducted a feasibility study on the CO2 geological storage in three candidate sites (sites A, B and C) offshore Japan. We present the results of the cost estimates for commercial-scale projects at the above sites with an injection rate of 1.54 million tons per year for 20 years. The overall storage costs range from approximately JPY 23 to 31 billion for the representative cases for each site.

Extreme weather significantly impacts construction schedules and costs and can be a source of schedule de­lays and budget overruns. A multi-objective optimization model, presented herein for the scheduling of construction projects under extreme weather conditions, can generate optimal/near optimal schedules that minimize the time and cost of construction projects in extreme weather regions. The model computations are organized as follows: (1) a scheduling module for developing practical schedules for construction projects, (2) a cost module for computing total project cost, and (3) a multi-objective module for determining optimal/near optimal trade-offs between project time and cost. Two practical examples of the effects of extreme weather on construction time and direct cost are provided, the first of which shows the impact of extreme weather on construction time and cost, and the second of which demonstrates the ability of the model to generate and visually present the optimal trade-offs between the duration and costs of construction projects under extreme weather conditions.

When reducing the cost of residential buildings, decreasing operational costs along with the construction costs will prove beneficial not only for the owner and/or user of the residence but also for national economy. In the design phase, decisions regarding building shape have a considerable effect on both construction costs and building heating energy costs. Therefore, this study will analyse the extent to which changes in building shape affect construction costs and building heating energy costs, and thereby provide pre-design information for future reference for residential buildings with less energy consumption and less environmental pollution. To this end, residential buildings with the same characteristics have been used by differentiating only building shapes, orientations and envelope alternatives to assess the changes they cause in construction, energy and life cycle costs.

This paper presents evidence of the disruption of a transition from fossil fuels to nuclear power, and finds the benefits forgone as a consequence are substantial. Learning rates are presented for nuclear power in seven countries, comprising 58% of all power reactors ever built globally. Learning rates and deployment rates changed in the late-1960s and 1970s from rapidly falling costs and accelerating deployment to rapidly rising costs and stalled deployment. Historical nuclear global capacity, electricity generation and overnight construction costs are compared with the counterfactual that pre-disruption learning and deployment rates had continued to 2015. Had the early rates continued, nuclear power could now be around 10% of its current cost. The additional nuclear power could have substituted for 69,000–186,000 TWh of coal and gas generation, thereby avoiding up to 9.5 million deaths and 174 Gt CO2 emissions. In 2015 alone, nuclear power could have replaced up to 100% of coal-generated and 76% of gas-generated electricity, thereby avoiding up to 540,000 deaths and 11 Gt CO2. Rapid progress was achieved in the past and could be again, with appropriate policies. Research is needed to identify impediments to progress, and policy is needed to remove them.

In high head dams, the kinetic energy at the spillway toe is very high and the tail-water depth available for energy dissipation is relatively small. Cascade stilling basins are energy dissipation systems for high head dams, the design of which is based on a trial-and-error procedure. Although such an approach yields feasible designs in which hydraulic and topographic considerations are met, there may exist many cost-effective designs. Therefore, optimization tools can help find the least construction cost while keeping hydraulic and topographic considerations satisfied. Particle Swarm Optimization (PSO) and Genetic Algorithms (GA) were used to determine the optimal design of cascade stilling basins in terms of the height of falls and length of stilling basins. The approach was evaluated by application to the design of an energy dissipation system for the Tehri Dam on the Bhagirathi River. Comparison of the proposed methods with dynamic programming and an alternative approach not utilizing an optimization tool revealed that GA and PSO lead to significant savings in the construction cost with less computational effort.

Since the first wave of nuclear reactors in 1970 to the construction of Generation III+ reactors in Finland and France in 2005 and 2007 respectively, nuclear power seems to be doomed to a cost escalation curse. In this paper we reexamine this issue for the French nuclear power fleet. Using the construction costs from the Cour des Comptes report, that was publicly available in 2012, we found that previous studies overestimated the cost escalation. Although, it is undeniable that the scale-up ended up in more costly reactors, we found evidence of a learning curve within the same size and type of reactors. This result confirms that standardization is a good direction to look, in order to overcome the cost escalation curse.

Construction is a major industry in fast growing countries and plays a leading role in the process of economic development. Using input-output tables, the performance of the construction sector in six emerging countries (Brazil, Russia, India, Indonesia, China and South Africa) is compared from 1995 to 2005. First, the construction performance in these developing economies, by using standard indicators based on value added, gross output, final demand and intermediate inputs, is investigated. Then, the similarity cosine index is introduced to assess structural change and differences in input expenditures between countries. This index is a useful tool for identifying input bundles that require a probing international comparison of construction performance.

Although, according to the ISO 14044 standard, economic allocation should be the solution of last resort, it is frequently used in LCA studies of agri-food systems because of the inadequacy of solutions preferred by ISO. We propose a new way of allocating impacts to plant co-products according to the underlying physical relationships between the co-products. We compare this method to two current allocation methods. (i) We surveyed 24 LCA studies from peer-reviewed scientific journals and scientific reports for the 2000-2013 period that attributed impacts to plant co-products used as animal feed to establish the prevalence of allocation methods in recent LCA studies. (ii) We calculated allocation factors for 21 plant co-products used as ingredients for animal feeds according to three methods: energy allocation based on lower heating values (En), economic allocation based on average prices for a 5-year period (Ec), and allocation based on plant physiological construction cost of plant compounds (Cc). (i) In the studies surveyed, Ec was used in 19 out of 24 cases. En was used in three studies, system expansion and mass allocation were used in two studies, while nitrogen content was used in one study. (ii) Compared to En and Ec, Cc yielded higher allocation factors for protein-rich co-products and lower factors for lipids. Whereas the difference between En and Cc was modest (up to 5 percentage points), the difference between Ec and Cc was more variable and sometimes large (up to 18 percentage points). Although, according to the ISO 14044 standard, Ec should be the solution of last resort, it is frequently used in LCA studies of agri-food systems because of the inadequacy of solutions preferred by ISO. For plant co-products, Cc is an attractive option, as it is based on the physiological mechanisms involved in plant growth rather than on a common property of the co-products.

The literature states that project duration is affected by various scope factors. Using 168 building projects carried out in Spain, this paper uses the multiple regression analysis to develop a forecast model that allows estimating project duration of new builds. The proposed model uses project type, gross floor area (GFA), the cost/GFA relationship and number of floors as predictor variables. The research identified the logarithmic form of construction speed as the most appropriate response variable. GFA has greater influence than cost on project duration but both factors are necessary to achieve a forecast model with the highest accuracy. We developed an analysis to verify the stability of forecasted values and showed how a model with high values of fit and accuracy may display an anomalous behavior in the forecasted values. The sensitivity of the proposed forecast model was also analyzed versus the variability of construction costs. The study presented in this paper was mainly funded by a research grant awarded by the Office of the Vice President for Research, Development and Innovation of the University of Alicante (resolution 22 December 2011). It has also been partially funded by the Spanish Government through the project TEXTMESS 2.0 (TIN2009-13391-C04) and by the Valencian Government through the project PROMETEO (PROMETEO/2009/199).

Studies which reduce cement usage, develop an alternative by partial replacement of cement with blast-furnace slag, fly ash, or such industrial byproducts, and evaluate the environmental load and economic value of concrete mixed with such are in high demand. In this study, A-BFS (Activator Blast Furnace Slag), which is mixed with an activator in order to induce early-age strength manifestation of BFS mixed concrete was used to execute a physical property evaluation of concrete. This study first conducted physical property tests for compression strength of concrete that partially replaced OPC (ordinary Portland cement) with A-BFS and executed a comparison/analysis with 100% OPC. It was thought that if concrete early strength is manifested through this process when applied to RC (Reinforced Concrete) building, at most a three to four day construction cycle would be possible, according to which the economic value of the construction period reduction was evaluated. For this evaluation, general apartment houses (Case 1) were taken as the evaluation subject, and for comparison, Cases 2, 3, and 4 were set up by the mix ratio of A-BFS, and the economic value evaluation range was established. As a result, it was found that Case 2 had no change from Case 1, while Case 3 saved about 106,654,762 KRW (Korea Won) and Case 4 saved about 159,982,143 KRW.

The duration of a highway construction project depends primarily on the quantity or magnitude of the construction work and the productivity of the construction crew. In addition, many other factors may also affect the construction duration, such as the type of construction, traffic features, location (urban or rural site), and weather conditions. When a state highway construction project contract is bid, a reasonable time must set and specified in the contract documents for completion of the contracted project. The time for contract completion (often called “contract time”) is estimated based on the average completion times of individual construction items within a specific project. Through this study, the Indiana Department of Transportation (INDOT) highway construction production rates were calculated and two methods for contract time estimations were developed based on the recorded eight-year INDOT construction data. Various statistics of production rates were provided to capture the main features of the highway construction production. The statistics include means, standard deviations, confidence intervals, mean baseline production rates, and production rates for different probabilities. The major factors that affect highway construction production rates were examined and their effects were analyzed. It was found that the production rates were affected by weather conditions in terms of temperatures and seasons, contractors, locations of construction projects (urban and rural), types of highways, and traffic conditions. Therefore, production rates under different conditions, such as seasons, roadway types and locations, were obtained to reflect the differences in production rates. The models for estimating highway construction contract times were developed. One of the methods uses regression equations to estimate contract times of highway construction projects. The other method estimates contract times with mean production rates of critical construction activities.

This paper presents a case study that relates the energy efficiency of a building, its construction costs and its energy consumption. The variation of the energy performance of the dwellings –and its energy rating- is made through changes in the envelope and the energy production systems. This theoretical study was conducted during the years 2009-2010 on the project of a residential block of apartments located in Madrid. The paper develops a methodology to evaluate the energy efficiency variations in a project and its economic implications. This will enable developers and architects to assess how the adoption of active and passive solutions affects the energy rating of a building, its energy consumption and its construction costs. The relationship between the orientation of housing and its energy rating, and the characteristics of the calculation programs used is also analyzed.Este artículo presenta un caso de estudio en el que, mediante la calificación energética, se relacionan la eficiencia energética de un edificio, sus costes de construcción y sus consumos energéticos. La variación del comportamiento energético del edificio se realiza a través de cambios en la envolvente y los sistemas de producción de energía. El estudio es teórico y fue realizado en 2009-2010 sobre el proyecto de un edificio residencial de protección oficial situado en Madrid. El trabajo desarrolla una metodología que permite evaluar las variaciones de eficiencia energética en un proyecto y sus implicaciones económicas. Ello permitirá a promotores y arquitectos valorar cómo la adopción de medidas activas y pasivas afecta a la calificación energética de un edificio, a su consumo de energía y a los costes constructivos. Además se analiza la relación entre la orientación de las viviendas y la calificación energética, y las características de los programas utilizados.

This paper presents the results of a survey of factors influencing the construction costs of Industrialised Building System (IBS) projects in Malaysia. The aim of the study was to evaluate and rank a range of factors that Malaysian IBS stakeholders regard as important, with the key identified factors being those associated with the main project characteristics, contract procedures and procurement methods, contractors’ and consultants’ attributes and design parameters besides external market conditions. Remarkably, factors grouped under the consultants and design parameters, external factors and government/authority requirements indicate low RII index while project/IBS characteristics, contractor attributes, external market conditions denote high RII index.