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Construction Costs (construction + cost)

Distribution by Scientific Domains

Life Sciences	31%
Engineering	26%
Business, Economics, Finance and Accounting	26%

Selected Abstracts

CONSTRUCTION COSTS AND THE SUPPLY OF HOUSING STRUCTURE,

JOURNAL OF REGIONAL SCIENCE, Issue 4 2006
Joseph Gyourko
ABSTRACT Construction costs account for the bulk of the price of new houses in most markets, but their study has been relatively neglected. We document that there are economically large differences in construction costs across U.S. housing markets. We also estimate a very elastic supply for physical structure; hence, differences in construction activity across markets do not explain the variation in costs. Supply shifters that collectively do account for differences in building costs include the extent of unionization within the construction sector, local wages, local topography in terms of the presence of high hills and mountains, and the local regulatory environment. [source]

Project Labor Agreements' Effect on School Construction Costs in Massachusetts

INDUSTRIAL RELATIONS, Issue 1 2010
DALE BELMAN
This paper investigates the impact of Project Labor Agreements (PLAs) on school construction cost in Massachusetts. Although simple models exhibit a large positive effect of PLAs on construction costs, such effects are absent from more completely specified models. Further investigation finds sufficient dissimilarity in schools built with and without PLAs that it is difficult to distinguish the cost effects of PLAs from the cost effects of factors that underlie the use of PLAs. [source]

Seismic design of RC structures: A critical assessment in the framework of multi-objective optimization

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 12 2007
Nikos D. Lagaros
Abstract The assessment of seismic design codes has been the subject of intensive research work in an effort to reveal weak points that originated from the limitations in predicting with acceptable precision the response of the structures under moderate or severe earthquakes. The objective of this work is to evaluate the European seismic design code, i.e. the Eurocode 8 (EC8), when used for the design of 3D reinforced concrete buildings, versus a performance-based design (PBD) procedure, in the framework of a multi-objective optimization concept. The initial construction cost and the maximum interstorey drift for the 10/50 hazard level are the two objectives considered for the formulation of the multi-objective optimization problem. The solution of such optimization problems is represented by the Pareto front curve which is the geometric locus of all Pareto optimum solutions. Limit-state fragility curves for selected designs, taken from the Pareto front curves of the EC8 and PBD formulations, are developed for assessing the two seismic design procedures. Through this comparison it was found that a linear analysis in conjunction with the behaviour factor q of EC8 cannot capture the nonlinear behaviour of an RC structure. Consequently the corrected EC8 Pareto front curve, using the nonlinear static procedure, differs significantly with regard to the corresponding Pareto front obtained according to EC8. Furthermore, similar designs, with respect to the initial construction cost, obtained through the EC8 and PBD formulations were found to exhibit different maximum interstorey drift and limit-state fragility curves. Copyright © 2007 John Wiley & Sons, Ltd. [source]

PERSPECTIVE: Rethinking the value of high wood density

FUNCTIONAL ECOLOGY, Issue 4 2010
Markku Larjavaara
Summary 1.,Current thinking holds that wood density mediates a tradeoff between strength and economy of construction, with higher wood density providing higher strength but at higher cost. 2.,Yet the further away wood fibres are from the central axis of the trunk, the more they increase the strength of the trunk; thus, a fat trunk of low-density wood can achieve greater strength at lower construction cost than a thin trunk of high-density wood. 3.,What then are the countervailing advantages of high wood density? 4.,We hypothesize that high wood density is associated with lower maintenance costs due to lower trunk surface area, as surface area correlates with maintenance respiration. 5.,This advantage would be particularly important to long-lived trees and could in part explain why they tend to have high wood density. 6.,High wood density has also been associated with lower risk of trunk breakage, xylem implosion and pathogen invasion, but we argue that these relationships are not causal and instead reflect correlated selection on other traits of value to long-lived trees. 7.,This revaluation of the costs and benefits of high wood density has important implications for understanding tree life-history evolution, functional diversity, forest carbon stocks and the impacts of global change. [source]

Project Labor Agreements' Effect on School Construction Costs in Massachusetts

Dynamic reduction of a CH4/air chemical mechanism appropriate for investigating vortex,flame interactions

INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 4 2007
Shaheen R. Tonse
This paper describes two methods, piecewise reusable implementation of solution mapping (PRISM) and dynamic steady-state approximation (DYSSA), in which chemistry is reduced dynamically to reduce the computational burden in combustion simulations. Each method utilizes the large range in species timescales to reduce the dimensionality to the number of species with slow timescales. The methods are applied within a framework that uses hypercubes to partition multidimensional chemical composition space, where each chemical species concentration, plus temperature, is represented by an axis in space. The dimensionality of the problem is reduced uniquely in each hypercube, but the dimensionality of chemical composition space is not reduced. The dimensionality reduction is dynamic and is different for different hypercubes, thereby escaping the restrictions of global methods in which reductions must be valid for all chemical mixtures. PRISM constructs polynomial equations in each hypercube, replacing the chemical kinetic ordinary differential equation (ODE) system with a set of quadratic polynomials with terms related to the number of species with slow timescales. Earlier versions of PRISM were applied to smaller chemical mechanisms and used all chemical species concentrations as terms. DYSSA is a dynamic treatment of the steady-state approximation and uses the fast,slow timescale separation to determine the set of steady-state species in each hypercube. A reduced number of chemical kinetic ODEs are integrated rather than the original full set. PRISM and DYSSA are evaluated for simulations of a pair of counterrotating vortices interacting with a premixed CH4/air laminar flame. DYSSA is sufficiently accurate for use in combustion simulations, and when relative errors are less than 1.0%, speedups on the order of 3 are observed. PRISM does not perform as well as DYSSA with respect to accuracy and efficiency. Although the polynomial evaluation that replaces the ODE solver is sufficiently fast, polynomials are not reused sufficiently to enable their construction cost to be recovered. © 2007 Wiley Periodicals, Inc. 39: 204,220, 2007 [source]

A multidegree-of-freedom manipulator for curtain-wall installation

JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 5 2006
Chang Soo Han
Recently, the trend in architectural forms has been towards larger and taller buildings. Building materials are, therefore, also becoming larger and heavier. Typical construction machineries are not adequate for handling such materials, and most construction works are still managed by a human operator. Construction processes are, therefore, fraught with a number of problems, including frequent accidents, high construction cost, and heterogeneous construction quality depending on the experience of the workers. Automation has been introduced at various sites to address these construction problems. In this paper, the process of a curtain-wall installation in a skyscraper is analyzed, and the prototype of a construction robot for curtain-wall installation (CRCWI) is proposed. Use of the proposed CRCWI can reduce the need for manpower and the construction period and cost, and can assure safety in the curtain-wall construction site. The performance of the proposed CRCWI was verified with a real application test in a skyscraper construction site. © 2006 Wiley Periodicals, Inc. [source]

Groundwater Banking in Aquifers that Interact With Surface Water: Aquifer Response Functions and Double-Entry Accounting,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2009
Bryce A. Contor
Contor, Bryce A., 2009. Groundwater Banking in Aquifers That Interact With Surface Water: Aquifer Response Functions and Double-Entry Accounting. Journal of the American Water Resources Association (JAWRA) 45(6):1465-1474. Abstract:, Increasing worldwide demands for water call for mechanisms to facilitate storage of seasonal supplies and mechanisms to facilitate reallocation of water. Markets are economically efficient reallocation and incentive mechanisms when market conditions prevail, but special hydrologic and administrative conditions of water use and allocation interfere with required market conditions. Water banking in general can bring market forces to bear on water storage and reallocation, improving economic efficiency and therefore the welfare of society as a whole. Groundwater banking can utilize advantages of aquifers as storage vessels with vast capacity, low construction cost, and protection of stored water. For groundwater banking in aquifers that interact with surface water, an accounting system is needed that addresses the depletion of stored volumes of water as water migrates to surface water. Constructing such a system requires integration of hydrologic, economic, and legal principles with principles of financial accounting. Simple mass-balance accounting, even with allowances for depletion, is not adequate in these aquifers. Aquifer response functions are mathematical descriptions of the impact that aquifer pumping or recharge events have upon hydraulically connected surface water bodies. Double-entry accounting is a financial accounting methodology for tracking asset inventories and ownership claims upon assets. The powerful innovation of linking aquifer response functions with double-entry accounting technologies allows application of groundwater banking to aquifers where deposits can be depleted by migration to hydraulically connected surface water. It honors the hydrologic realities of groundwater/surface water interaction, the legal requirements of prior appropriation water law, and the economic requirements for equitable and efficient allocation of resources. [source]

Chemical composition and construction cost for roots of Mediterranean trees, shrub species and grassland communities

PLANT CELL & ENVIRONMENT, Issue 5 2002
F. Martínez
Abstract The construction cost of fine roots was studied in 23 woody species and two grassland communities, growing under natural conditions in southern Spain. Calculation of the energy (glucose) required for their synthesis was based on the quantification of chemical components present in tissues. Despite considerable differences in the chemical composition of the three life forms studied (trees, shrubs and herbaceous), detected differences in construction cost were non-significant (mean value: 1·64 ± 0·13 g glucose g,1). However, shrubs and herbaceous plants growing in more fertile habitats expended significantly less energy on root synthesis (1·58 ± 0·06 and 1·41 ± 0·05 g glucose g,1, respectively) than those growing in less fertile areas (1·80 ± 0·06 and 1·57 ± 0·1 g glucose g,1, respectively), because they contained smaller amounts of either waxes (shrubs) or lignins (herbaceous), both expensive to synthesize, and, proportionately, more cellulose; which is inexpensive to synthesize. Deciduous and evergreen tree species also differed mainly with regard to wax and cellulose contents, giving rise to a significantly higher construction cost in evergreens (1·57 ± 0·07 g glucose g,1 versus 1·78 ± 0·02 g glucose g,1). The differences observed in construction cost appeared to be due more to habitat-induced differences in chemical composition than to any intrinsic difference between the species studied. [source]

The growth respiration component in eddy CO2 flux from a Quercus ilex mediterranean forest

GLOBAL CHANGE BIOLOGY, Issue 9 2004
S. Rambal
Abstract Ecosystem respiration, arising from soil decomposition as well as from plant maintenance and growth, has been shown to be the most important component of carbon exchange in most terrestrial ecosystems. The goal of this study was to estimate the growth component of whole-ecosystem respiration in a Mediterranean evergreen oak (Quercus ilex) forest over the course of 3 years. Ecosystem respiration (Reco) was determined from night-time carbon dioxide flux (Fc) using eddy correlation when friction velocity (u*) was greater than 0.35 m s,1 We postulated that growth respiration could be evaluated as a residual after removing modeled base Reco from whole-ecosystem Reco during periods when growth was most likely occurring. We observed that the model deviated from the night-time Fc -based Reco during the period from early February to early July with the largest discrepancies occurring at the end of May, coinciding with budburst when active aboveground growth and radial growth increment are greatest. The highest growth respiration rates were observed in 2001 with daily fluxes reaching up to 4 g C m,2. The cumulative growth respiration for the entire growth period gave total carbon losses of 170, 208, and 142 g C m,2 for 1999, 2001, and 2002, respectively. Biochemical analysis of soluble carbohydrates, starch, cellulose, hemicellulose, proteins, lignin, and lipids for leaves and stems allowed calculation of the total construction costs of the different growth components, which yielded values of 154, 200, and 150 g C for 3 years, respectively, corresponding well to estimated growth respiration. Estimates of both leaf and stem growth showed very large interannual variation, although average growth respiration coefficients and average yield of growth processes were fairly constant over the 3 years and close to literature values. The time course of the growth respiration may be explained by the growth pattern of leaves and stems and by cambial activity. This approach has potential applications for interpreting the effects of climate variation, disturbances, and management practices on growth and ecosystem respiration. [source]

Project Labor Agreements' Effect on School Construction Costs in Massachusetts

Beehive fence deters crop-raiding elephants

AFRICAN JOURNAL OF ECOLOGY, Issue 2 2009
Lucy E. King
Abstract Previous work has shown that African elephants Loxodonta africana will avoid African honeybees Apis mellifera scutellata. Here we present results from a pilot study conducted to evaluate the concept of using beehives to mitigate elephant crop depredation. In Laikipia, Kenya, we deployed a 90-m fence-line of nine inter-connected hives, all empty, on two exposed sides of a square two-acre farm that was experiencing high levels of elephant crop depredation. Compared with a nearby control farm of similar status and size, our experimental farm experienced fewer raids and consequently had higher productivity. Socioeconomic indicators suggest that not only was the concept of a beehive fence popular and desired by the community but also that it can pay for its construction costs through the sale of honey and bee products. We are calling for experiments testing this concept of a ,guardian beehive-fence' to be conducted rigorously and scientifically in as wide a range of agricultural settings as possible to evaluate jointly its effectiveness and efficiency. Résumé Des travaux antérieurs ont montré que les éléphants africains Loxodonta africanaévitent les abeilles africaines Apis mellifera scutellata. Nous présentons ici les résultats d'une étude pilote réalisée pour évaluer le concept consistant à utiliser des ruches pour réduire la destruction des cultures par les éléphants. A Laikipia, au Kenya, nous avons installé une barrière de 90 m. de long composée de neuf ruches interconnectées, toutes vides, sur deux côtés exposés d'une ferme carrée de deux acres (arpents) dont les cultures subissaient une forte déprédation causée par les éléphants. Comparée à une ferme contrôle voisine, de statut et de taille comparables, notre ferme expérimentale a subi moins de raids et a donc eu une meilleure productivité. Des indicateurs socioéconomiques suggèrent que non seulement le concept de barrière en ruches était populaire et souhaité par la communauté, mais qu'il peut même couvrir les frais de sa propre construction grâce à la vente de miel et autres produits dérivés. Nous sollicitons que des expériences soient faites pour tester ce concept de « clôture en ruches » de façon rigoureuse et scientifique, dans une gamme aussi étendue que possible d'installations agricoles, afin d'évaluer son efficacité et sa faisabilité. [source]

CONSTRUCTION COSTS AND THE SUPPLY OF HOUSING STRUCTURE,

ARTICULATED CONCRETE BLOCK STABILITY TESTING,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2001
Steven R. Abt
ABSTRACT: An articulated concrete block revetment system was developed by the U.S. Army Corps of Engineers to test and evaluate the practicability of the protocols for overtopping and channelized flow conditions. Test facilities were constructed, prototype articulated concrete blocks were fabricated and installed into the facilities, and the blocks were tested using the established protocols. The test results indicated that both the overtopping and channel flow tests yielded similar results: the blocks reached a point of instability at approximately the same velocity and shear stresses. The similar test results indicate that only one protocol is required to evaluate an articulated concrete block system. It was demonstrated that both protocols can be effectively conducted. It is recommended that the overtopping test be adapted as a standard test procedure because of its reduced construction costs and its efficiency compared to the channelized test. [source]

The option to change the use of a property when future property values and construction costs are uncertain

MANAGERIAL AND DECISION ECONOMICS, Issue 7 2001
Åke Gunnelin
This paper models the decision to change the use of a property when its value in the current use and the new use, as well as construction costs, are uncertain. In the case of development of vacant land, when cash flows and construction costs are lognormally distributed, the development of the property optimally takes place when the ratio of benefit to cost of development reaches some fixed level. In the redevelopment case, the timing problem is found to be more complex, as the cost of exercising the conversion option consists of two parts, the construction costs and the surrendered value of the property in the current use, which may evolve differently over time. In this case, optimal redevelopment will take place for different benefit,cost ratios, depending on the relative sizes of the property values in the different uses and the construction costs. Also, for a given current benefit,cost ratio, the option value will vary significantly, depending on the relative size of the state variables. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Direct and indirect effects of elevated CO2 on leaf respiration in a forest ecosystem

PLANT CELL & ENVIRONMENT, Issue 9 2001
J. G. Hamilton
Abstract We measured the short-term direct and long-term indirect effects of elevated CO2 on leaf dark respiration of loblolly pine (Pinus taeda) and sweetgum (Liquidambar styraciflua) in an intact forest ecosystem. Trees were exposed to ambient or ambient + 200 µmol mol,1 atmospheric CO2 using free-air carbon dioxide enrichment (FACE) technology. After correcting for measurement artefacts, a short-term 200 µmol mol,1 increase in CO2 reduced leaf respiration by 7,14% for sweetgum and had essentially no effect on loblolly pine. This direct suppression of respiration was independent of the CO2 concentration under which the trees were grown. Growth under elevated CO2 did not appear to have any long-term indirect effects on leaf maintenance respiration rates or the response of respiration to changes in temperature (Q10, R0). Also, we found no relationship between mass-based respiration rates and leaf total nitrogen concentrations. Leaf construction costs were unaffected by growth CO2 concentration, although leaf construction respiration decreased at elevated CO2 in both species for leaves at the top of the canopy. We conclude that elevated CO2 has little effect on leaf tissue respiration, and that the influence of elevated CO2 on plant respiratory carbon flux is primarily through increased biomass. [source]

Q- und R-Matten aus Kunststoff für Bewehrungsaufgaben in der Geotechnik

BAUTECHNIK, Issue 9 2004
Georg Heerten Dr.-Ing.
Wachsende Güterströme und Warenverkehre im Zentrum eines wachsenden Europas und zunehmender Warenaustausch als Folge der Globalisierung der Weltwirtschaft stellen erhebliche Anforderungen an den Erhalt und Ausbau leistungsfähiger Infrastruktursysteme (Straße, Schiene, Wasserstraße). Nachhaltigkeitskonzepte bei der Bautätigkeit und Finanzierungsprobleme der öffentlichen Auftraggeber sind aktuelle Randbedingungen, denen mit Geokunststoff-Bauweisen optimal Rechnung getragen werden kann. Es können neben den technischen auch die ökonomischen und ökologischen Vorteile , Baukosten sparen, Baustoffressourcen schonen , parallel genutzt werden. Eine Stützwand als "Bewehrte-Erde-Konstruktion" kann ganz erheblich kostengünstiger als eine Stahlbeton-Stützmauer hergestellt werden. Die Ertüchtigung von wenig tragfähigen Böden mit flächig angeordneten Bewehrungslagen und/oder pfahlartigen geokunststoffummantelten Bodensäulen vermeidet umfangreichen Bodenaustausch, spart Kosten, verhindert umfangreichen Transport von Bodenmassen mit LKWs. Hierdurch werden knappe Baustoffressourcen wie Sand und Kies geschont sowie eine z. T. erhebliche Entlastung örtlicher Verkehrswege bewirkt. Q and R mats made of synthetics for reinforcement functions in the field of geotechnics. An increasing flow of goods in a growing central Europe, resulting from the globalisation of the world economy, makes high demands on the maintenance and development of an efficient infrastructure (road, railway, waterway). Sustainability concepts for the construction activities and funding problems of the contracting authorities are current boundary conditions which can be accommodated optimally with geosynthetic construction methods. At the same time, besides the technical advantages, the economical and ecological advantages can be used too , saving of construction costs and taking care of building materials resources. A retaining wall as "Reinforced-Earth-Structure" can be constructed at much lower cost than a retaining wall made of reinforced concrete. The improvement of subsoils with low bearing capacity, by using reinforcing layers in the area and/or soil columns similar to piles wrapped with geosynthetics, avoids a considerable exchange of soil, saves costs and avoids substantial soil transports by trucks. Thus, care is taken on rare building materials resources like sand and gravel and the traffic routes are partly released to a high extent. [source]