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The purpose of this paper is to examine the degree of productivity change in the construction industry and relate these changes to variations in the business cycle. The activity of Spanish firms engaged in the construction of buildings, civil engineering, and specialized activities during the 2000s is used as a case study. Productivity change is estimated by creating a bilateral index using data envelopment analysis, complemented with bootstrapping. The results showed that Spanish firms in building construction experienced a fall in productivity because of a decline in technical and scale efficiencies, despite improvements in technology. The productivity change in civil engineering and specialized construction also was negative; however, the source of this decline was technical regress and negative scale efficiency change, although efficiency change and technology scale change contributed positively. The results further revealed that the firms reacted to the financial crisis of the late 2000s by introducing technological change, although the productive, technical, and scale efficiency changes all were negatively impacted during the economic downturn, suggesting an underuse of resources. This research contributes to the body of knowledge by being the first to analyze the impact of fluctuations in business cycles caused by the 2008 economic crisis on the productivity growth of construction firms representing three construction sectors, and by measuring productivity growth from a multidimensional perspective. [ABSTRACT FROM AUTHOR]

According to some studies, flat roofs are one of the construction elements that most frequently suffer from damage and anomalies. It is important to carry out a verification of the execution processes of waterproofing membranes to reduce the number of failures as much as possible and prevent future associated damages. This paper details the 47 evaluation parameters that were applied to 61 construction projects, rated in terms of their quality in five levels of importance of the deficiencies, based on the supervision performed by quality control entities during the execution of the works. The results numerically demonstrate the importance of prior supervision of project design to produce more satisfactory results and reduce the probability of problems in the future. The most common problems in flat roofs with bituminous membranes are identified and rated, of which issues concerning the tail-ends with peripheral elements stand out. [ABSTRACT FROM AUTHOR]

This paper assesses technical efficiency and its determinants in the Spanish construction sector from a comparative perspective for the period 2000 to 2010 by using different parametric approaches in the form of stochastic frontier models. The main results reveal similar (no) influential factors on efficiency. For all models, the determinants found were capital intensity, prefinancial and postfinancial crisis periods, and workers' skills. There was no difference in terms of sign and statistical significance. Firm age was positively related to efficiency in two of the three models. Firm size was not significant in any model. Finally, the average efficiency values obtained by the models are 55.3, 69.2, and 91.0%, suggesting the possibility of significant improvements in resource management. [ABSTRACT FROM AUTHOR]

This paper examines the extent to which engineers can influence the competitive behavior of bidders in best value or multiattribute construction auctions, in which both the (dollar) bid and technical nonprice criteria are scored according to a scoring rule. From a sample of Spanish construction auctions with a variety of bid scoring rules, it is found that bidders are influenced by the auction rules in significant and predictable ways. The bid score weighting, bid scoring formula, and abnormally low bids criterion are variables likely to influence the competitiveness of bidders in terms of both their aggressive/conservative bidding and concentration/dispersion of bids. Revealing the influence of the bid scoring rules and their magnitude on bidders' competitive behavior opens the door for the engineer to condition bidder competitive behavior in such a way as to provide the balance needed to achieve the owner's desired strategic outcomes. [ABSTRACT FROM AUTHOR]

This paper presents the results of an innovative teaching experience in the area of structural analysis in the mechanical engineering program of the Universidad de Sevilla, Spain. The teaching methodology used is aimed at motivating students to learn by promoting the design, calculation, building, and testing of structures. This method not only trains students to make calculations, but also develops skills that allow them to understand how structures function. The project includes subjects taught in the third and fifth year of the course. In their third year, students begin their structural training studying structural analysis, where they learn the basics by designing, building, and testing balsa wood structures. Students have access to computer software when optimizing the design of their models before building and testing them in the laboratory. After this first approach to structural analysis, students receive training on more advanced concepts. A few examples of such concepts are the dynamic behavior of structures and instabilities in specific types of structures such as plates and laminar structures, and in structural materials such as steel and concrete. Before completing their studies, students are exposed to a project-based teaching methodology in the area of experimental structural analysis, where students deal with similar projects to those they will face as professionals after graduating. This paper explains the advantages of this methodology for teaching in engineering. [ABSTRACT FROM AUTHOR]

Temporary work at height is one of the primary causes of construction accidents that result in serious injuries and fatalities. Many of these accidents occur because of falls from scaffolding and work platforms. In Europe, scaffolding equipment for temporary work at height is regulated by several directives. A directive is a legislative act of the European Union, which requires member states to achieve a particular result without dictating the means of achieving that result. In this sense, the European standard is of great interest because it facilitates compliance with the requirements of a directive regarding temporary work at height. This paper presents the results of a research study that was conducted in Spain between March 2003 and 2004, in which 146 construction sites were inspected with a view to examining the scaffolding surface at each site. The building sites with scaffolding that complied with a European standard were compared with those with older (nonstandard) scaffolding. Both types were qualitatively evaluated to ascertain their safety levels. The findings reported in this paper demonstrate that the standardization of scaffolding equipment had a direct and positive impact on work safety conditions at construction sites. Consequently, fomenting standardization of scaffolding equipment in the construction industry can contribute to improving work safety conditions as has occurred in Spain. The methodology in the authors' paper can also be applied in other countries to evaluate their regulations or codes regarding personal protective equipment. [ABSTRACT FROM AUTHOR]

Time should be considered in carrying out the design and management of demand irrigation distribution systems. In this paper, a method to characterize the pumping flow in demand pressurized systems throughout the day and irrigation season is presented. This method considers the temporal evolution of water requirements during the irrigation season and water demand concentration in certain periods of the irrigation day due to different electrical energy charges. The model was established based on data from an actual water distribution network of an irrigation district in southern Spain. The results differed significantly from those obtained using approaches based on establishing a uniform working probability for the outlets of the water distribution network at all hours of the irrigation day, which underestimated the circulating flows or system capacity. The most probable pumping flow with uniform probability was 3.1 m3/s, a smaller value than those obtained in the off-peak and average energy tariff times (4 and 3.4 m3/s, respectively). The total energy head required at the booster pumping in each period of the irrigation season was simulated. 10,000 randomly chosen scenarios were simulated for each irrigation day and each energy tariff time. The heterogeneous vertical stratification between 50 and 103 m of the required piezometric head was obtained as a function of the demanded flow for the water distribution system. This paper includes a pump selection algorithm for recommending least cost or optimum pump combinations in the distribution network and to evaluate the system’s energy cost. The pump recommendations show that the optimal solution could have saved 41% of the pumping cost of the Fuente Palmera irrigation district. [ABSTRACT FROM AUTHOR]

The canal delivery system in the Left Hemidelta area of the Ebro River in Spain consists of a tree-shaped net of open canals. The overall system can be quickly isolated in the case of an emergency by closing the upstream pool. Transients, in which the initial state is hydraulically far from the final state, are difficult to handle and cannot be made in only one gate movement in order to protect the canal lining. Therefore, they have to be as smooth as possible. GoRoSo is a feedforward control algorithm for irrigation canals based on sequential quadratic programming. With this tool, it is possible to calculate the gate trajectories that smoothly carry the canal from the initial state to the final state by keeping the water depth constant at checkpoints. The paper shows the efficient implementation of GoRoSo in both the closure and opening operations of the canal delivery system. [ABSTRACT FROM AUTHOR]

In Spain, the high levels of inexperienced workers and the long chains of subcontracting contribute to the poor quality of dwellings. Although the Ley reguladora de la subcontratación en el Sector de la Construcción (subcontracting law) has established quality measures, the number of customer complaints is still increasing. In this paper, a total of 2,351 posthandover defects derived from four Spanish builders and seven residential developments are classified according to their source and origin. The research reveals that the most common defects identified by customers at posthandover were derived from bad workmanship and were related to construction errors and omissions. Typical defects were found to include incorrect installation, appearance defects, and missing an item or task mainly related to finishing and considered to be minor. No defects were caused by poor design because they are mainly detected and resolved during construction or become apparent after some years of use. This study demonstrates the negative impact of redoing defective work during the final stages of construction and provides knowledge to define measures to improve the quality of the finished buildings, such as understanding customer expectations and preferences, training programs for workers, specialization of subcontractors, and tightening external controls prior to handover. [ABSTRACT FROM AUTHOR]

University programs in Western countries must be accredited, and although several detailed conceptual methods have aimed to design new programs, no specific quantitative tools are currently available. The purpose of this paper is to describe a method to plan, design, or improve graduate degree programs based on selected requirements and market demands. This method involves two metrics, which are later combined into a final index. The first metric is the completeness index that evaluates the extent to which certain programs cover a discipline, in this case, construction management, according to a model using two variables: infrastructure life cycle and organizational breakdown. The second metric is the adequacy index, which measures how a program addresses the previously identified market demands. The final indicator (summary index) relates both indexes in a plot chart. In this study, the applicability of the method is illustrated by a sample of 21 construction management programs from prestigious universities and a survey of the Spanish construction industry. It can be applied in practice, not only in the construction management field, but also in other fields with an appropriate theoretical model that maps each field of knowledge and exploratory data that highlight the demands of each specific market. [ABSTRACT FROM AUTHOR]

Climate change will lead to changed demands on existing irrigation systems. This paper presents a methodology for investigating the performance of irrigation networks under climate change, and applies this to an irrigation network in Cordoba, southern Spain. The methodology uses emission scenarios (A2 and B2) developed by the Intergovernmental Panel on Climate Change. A global climate model (HadCM3) is used with downscaling to predict climate variables for 2050 and 2080 under the emission scenarios. European agricultural policy scenarios are used to predict future cropping patterns. Irrigation water requirements are then estimated for various combinations of these climate and cropping pattern scenarios, and the performance of the irrigation network is evaluated in terms of the equity and adequacy of pressure at the outlets, using EPANET. The methodology was applied to the Fuente Palmera irrigation district, which supplies water on-demand for drip irrigation. The results show that climate change would have a major impact on network performance with the existing cropping pattern, but that expected changes in cropping pattern would reduce this impact. [ABSTRACT FROM AUTHOR]

This paper presents an application of a coupled hydromechanical formulation for compacted and rockfill materials to simulate the construction and impoundment of a zoned earth dam. The constitutive relation used to model the mechanical behavior of the shoulder, filter and core materials is the Barcelona Basic Model for unsaturated materials. The hydraulic behavior of dam materials requires the specification of their water retention characteristics and their permeabilities, which will be expressed as a function of porosity and degree of saturation. The model was used in the design stage of Lechago’s dam (Teruel, Spain), currently under construction. Soil parameters were obtained by laboratory tests performed on materials to be used in the dam. The step-by-step construction (following the sequence construction of nine horizontal layers, besides the downstream preloading layers) and subsequent impounding of the reservoir was simulated in a prediction exercise, which will be hopefully confronted with actual construction measurements in the near future. A parametric study was also performed to evaluate the effects of the compaction water content of the core material on the behavior of the dam. [ABSTRACT FROM AUTHOR]

The modernization of irrigation districts in Spain is based on the construction of collective pressurized networks equipped with remote control systems. In this paper, a simulation approach is used to explore the benefits of introducing a collective solid-set irrigation control software. The controller works in combination with a district management database, real-time evapotranspiration and meteorology information, and a remote control system. Controller decisions are based on the simulation of sprinkler irrigation performance and on crop–water balance. The decision to irrigate a plot can be guided by the use of two simulation parameters: the estimated application efficiency of the irrigation event (heavily affected by wind speed) and a crop–water stress index. Simulation experiments were performed in a district located at the Ebro basin of Spain. The collective controller resulted in water conservation (with respect to the current situation) of 2,234 and 4,664 m3 ha-1 for corn and alfalfa, respectively, and in an increase in water productivity of up to 91%. Although additional research is needed to produce a reliable collective controller, these preliminary results are encouraging. [ABSTRACT FROM AUTHOR]

The purpose of the work summarized here was to improve the efficiency of the construction project management processes performed by the Spanish civil service, identifying and analyzing the main risks in these kinds of projects, and also establishing potential risk responses. The scope of this effort included a list of 96 risk events, categorized and prioritized first by impact, then by frequency. The most relevant ones are related to issues such as an inadequate prequalification system, insufficient training of public servants, or political considerations prevailing over real needs, among others. A total of 117 potential risk responses were identified, categorized, and prioritized by potential efficiency and difficulty of implementation. Each risk event was associated to a set of potential responses. The paper includes the top 15 risk events with its main potential responses, including qualitative assessments. A survey was carried out among Spanish public servants working in construction projects, to validate risk identification and to obtain a qualitative assessment. Moreover, a Delphi analysis was developed to validate the risk response identification and obtain a qualitative assessment. One of the conclusions is that small and medium-sized Spanish civil service agencies should work toward increasing their maturity in managing projects and, mainly, project risks. [ABSTRACT FROM AUTHOR]

This paper summarizes the state of knowledge in relation to advances in education for sustainable development focused on higher education and in generic competencies, reviewing some of the existing proposals in the literature and analyzing other university approaches. It has focused on the curricula, applying a participatory methodology based on surveys and expert consultation for the identification and selection of generic competencies related to sustainability in a civil engineering degree at Universidad Europea (Spain). From the literature review, 17 generic competencies were preselected. A set of five weighted transversal competencies and their acquisition level have been obtained through surveys to stakeholders and interviews with experts. Critical thinking, adaptation to change, decision making, problem solving, and multidisciplinary team-working were chosen in order of importance. Competence acquisition level was addressed as not easy to rate or it seems to be exigent for graduate students. Problem-based learning is also selected as the best choice for the development of these sustainability generic skills in the entire civil engineering degree. [ABSTRACT FROM AUTHOR]