Construction Cost

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.

The leaf properties and construction costs (CC) are reported for eight indigenous heath (kerangas) forest species and three invasive (exotic) species of Acacia. Both groups of species co-occur and colonise disturbed lowland tropical heath rainforest habitats in Brunei, Borneo Island. Across species, CC mass-based increased with nitrogen (N) and heat of combustion (H C ), and decreased with ash content. CC area-based showed similar trends (although weaker in strength) in addition to significant positive correlation with leaf mass per unit area (LMA). Within the native species, the CCs of the shrub and small tree species were lower and significantly different from those of medium-sized tree species. Given the invasive success of the three acacias, it is hypothesised that these species may require less energy for biomass construction than do the native species. Within similar life growth form, no difference in CC mass-based was detected between the native trees and the invasive acacias. For CC area-based, the invasive Acacia species had a higher value. These findings failed to uphold our hypothesis. LMA and leaf N and phosphorus (P), but not potassium (K), were higher in the invasive acacias. The higher N and LMA could have been the cause of higher CC area-based in the invasive acacias. From the ordination of 11 species on the basis of leaf properties, the invasive and native species are more likely to be found in different groupings-although some native species seem more affiliated with the invasive than with their own guild, especially Alphitonia and Macaranga.

The construction of large pipeline infrastructures for CH 4 , CO 2 and H 2 transportation usually constitutes a major and time-consuming undertaking, because of safety and environmental issues, legal and (geo)political siting arguments, technically un-trivial installation processes, and/or high investment cost requirements. In this paper we focus on the latter and present an overview of both the total costs and cost components of the transmission of these three gases via pipelines. Possible intricacies and external factors that strongly influence these costs, like the choice of location and terrain, are also included in our analysis. Our cost breakdown estimates are based on transportation data for CH 4 , which we adjust for CO 2 and H 2 in order to account for the specific additional characteristics of these two gases. Our main finding is that the economics of CH 4 , CO 2 and H 2 transportation through pipelines are volatile. In particular for CH 4 and CO 2 the overall trend seems that pipeline construction costs have not decreased over recent decades or, at least, that possible reductions in overall costs have been outshadowed by the variability in the costs of key inputs. We speculate on the reasons why we observe limited learning-by-doing effects and expect that negligible construction cost reductions for future CH 4 and CO 2 pipeline projects will materialize. Cost data of individual pipeline projects may strongly deviate from the global average because of national or regional effects, such as related to varying costs of labor and fluctuating market prices of components like steel. We conclude that only in an optimistic scenario we may observe learning effects for H 2 pipeline construction activity in the future, but there are currently insufficient data to fully support the limited evidence for this claim, so that the uncertainty of this prediction for now remains large.

Development of performance-based design (PBD) methodologies for buildings and a better understanding of the performance and damage to nonstructural components during ground motion events give rise to design problems that involve structural and nonstructural component performance. The current research effort is geared toward development of an automated PBD environment to optimize structural system performance. FEMA-350 and HAZUS procedures are used

Civil engineering projects include several uncertainties and risks, due to the special characteristics of construction industry. Time and cost are two parameters that could potentially lead to successful and conforming to regulations production of projects. It is imperative to estimate correctly the development and the final outcome of these parameters. Various tools have been applied in order to create more accurate estimations. In this paper, a prototype system will be presented, which aims at predicting the final cost, based on information available at the bidding stage. The methodology will be based on a combination of regression analysis and case-based reasoning in order to produce models for the prediction of final cost. These models will incorporate a process view and will depend on activity based costing methodology to estimate the process cost.

Despite the extensive use of simulation in management, the continuous simulation model for cost estimation remains unexploited, especially for construction engineering and management. This study introduces streamlining Monte Carlo simulation procedures with evaluation of stochastic processes and input probability distribution selection via hypothesis testing, and specification of correlations between simulated variates. By using self-developed algorithms and a spreadsheet-add-on program, this investigation uses historical construction projects as case study data to create an early-stage cost distribution for budget allocation. While establishing the applicability of the proposed simulation procedures, this study demonstrates that the simulated cost results present superior simulation accuracy in addition to separating the principal work items and unit price component model. Generally, the precision and absolute error rates fall into acceptable ranges when the proposed systematic simulation procedures are adopted. The cost simulation approach offers a simplified decision tool for fairly assessing construction cost and uncertainties based on the experienced judgment of project managers.

* 2. If the corresponding P-value is less than a pre-determinedα , the X variable is added. 3. Assume X7 is the variable added in step 1, the stepwise regression routine now fits next regression model with two X variables, where X7 is one of the pair.

There is an increasing interest by Departments of Transportation in the development and implementation of durable structural systems for accelerated bridge construction. The main objective is to minimize construction costs, and the impact of the economic and social costs associated with rehabilitation or replacement of a significant portion of the US bridge inventory. This paper reports on the development of an innovative glass fiber reinforced polymer (GFRP) reinforcement for the rapid construction of concrete bridge deck and parapet systems. The deck reinforcement comprises prefabricated modular stay-in-place (SIP) panels (gridforms), consisting of two-layer, three-dimensional grating made of off-the-shelf pultruded shapes, with an epoxy-bonded bottom formwork plate. Pre-assembled GFRP rebar cages are utilized as reinforcement for the open-post concrete parapet. Detailing and construction procedures have been addressed to improve safety and constructibility. Laboratory testing demonstrated the structural adequacy of gridform reinforced slabs under design service loads, and of a first post/deck connection configuration. The system will be implemented in the construction of the new Bridge 14802301 in Greene County, MO, scheduled for completion in November 2005.

The cost of building rail transit facilities in the United States has skyrocketed in recent decades. Sections of Los Angeles's Red Line subway cost more than $750 million per mile to build and even less pricey light-rail systems can cost more than $200 million per mile. Soaring capital investment costs are today's biggest deterrent, both political and financial, to constructing new transit infrastructure. It stands to reason that high-cost transit projects need high ridership levels. Without sufficient numbers of riders and the fares they generate, new rail investments will inevitably incur huge deficits. Nor will environmental benefits accrue. Transit only reduces traffic congestion and tailpipe emissions when it draws former motorists -and particularly single-occupant drivers -to trains and buses. A system with few riders and a high price tag is a poor investment compared to a system with many riders and a low price tag.

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.

Identification of cost-determinant variables and evaluation of their degree of influence play an essential role in building reliable cost models and enhance the competitive edge of quantity surveyors as well as contracting organisations. Sixty-seven variables affecting pre-tender construction cost estimates are identified through literature and interviews. These factors are grouped into six categories and a comparison analysis of their impact is conducted. Priority ranking of cost-influencing factors is carried out using a questionnaire survey commissioned amongst quantity surveyors based in the UK. Findings of this survey indicate that there is a strong agreement between quantity surveyors in ranking cost-influencing factors of construction projects. Comparisons between the outcomes of this research and other related studies are presented.

Energy storage systems are becoming more important for load leveling, especially because of the widespread use of intermittent renewable energy. Compressed air energy storage (CAES) is a very promising method for energy storage because CAES relies on existing technologies, is less expensive, and easier to site and permit, as compared to pumped hydro storage. But, in the case of CAES employing hard rock caverns or man-made air vessels, although the smallest possible cavern volume is desirable in order to minimize the construction cost and optimize utilization of the given space, the operating pressure range in the cavern must be limited in order to reduce the deterioration in efficiency of the CAES system at off-design conditions. In this paper, a new constant-pressure CAES system combined with pumped hydro storage was studied to address the current problem associated with the conventional CAES systems. An energy and exergy analysis of the novel CAES system was performed in order to understand the operation characteristics of the system according to several different compression and expansion processes; we then examined the effects of the height of the storage cavern and heat transfer between two media (air, water) and the cavern on the performance of the novel CAES system.

Rainwater tanks for larger roof areas need optimisation of tank size, which is often not carried out before installation of these tanks. This paper presents a case study of rainwater tank evaluation and design for large roof areas, located in Melbourne, Australia, based on observed daily rainfall data representing three different climatic regimes (i.e. dry average, and wet years). With the aim of developing a comprehensive Decision Support Tool for the performance analysis and design of rainwater tanks, a simple spreadsheet based daily water balance model is developed using daily rainfall data, contributing roof area, rainfall loss factor, available storage volume, tank overflow and irrigation water demand. In this case study, two (185 m 3 and 110 m 3 ) underground rainwater tanks are considered. Using the developed model, effectiveness of each tank under different climatic scenarios are assessed. The analysis shows that both the tanks are quite effective in wet and average years, however less effective in dry years. A payback period analysis of the tanks is preformed which reveals that the total construction cost of the tanks can be recovered within 15-21 years time depending on tank size, climatic conditions and future water price increase rates. For the tanks, a relationship between water price increase rates and payback periods is developed. The study highlights the need for detailed optimisation and financial analysis for large rainwater tanks to maximise the benefits.

The launch and deployment of picosatellites from the Stanford University OPAL microsatellite in February 2000 demonstrate the feasibility and practicability of a new age of space experimentation. Two of the six picosatellites deployed from OPAL were built by ...

This paper investigates the overhead cost practices of construction companies in Saudi Arabia. Although overhead costs are extremely important in construction estimation, they can be easily overlooked. Neglecting overhead has forced some contractors out of business, because these costs constitute a signi®cant portion of the total construction cost. The practices of 61 large building construction contractors were investigated via questionnaire. The questionnaire has three parts covering the construction ®rms, overhead costs in general, and company overhead costs. Results show that average overhead cost is slightly higher than the ratio reported in the literature. The average percentage of company overhead costs to project direct cost is greater than 10%. Causes of increased company overhead costs include delayed payments, shortage of new projects, cost of in¯ation and governmental regulations. Factors aecting company overhead costs include the following: automobile and equipment costs, head oce expenses, labor related costs and ®nancing costs. The unstable construction market makes it dicult for contractors to decide on the optimum level of overhead costs that enables contractors to win and eciently administer large projects. #

Laboratory experiments have shown a large difference in specific leaf area (SLA, leaf area : leaf mass) between species from nutrient-poor and nutrient-rich habitats, but no systematic difference in the construction costs (the amount of glucose required to construct 1 g biomass). We examined how far these patterns are congruent with those from field-grown plants. An analysis was made of the vegetation in a range of grasslands and heathlands differing in productivity. The SLA of the dominant species in 15 different habitats was determined, as well as chemical composition and construction costs of bulk samples of leaves. SLA in the field was generally lower than in the laboratory, but showed consistency in that the ranking across species remained the same. Species from highly productive habitats had higher SLA than those from sites of low productivity, although individual species sometimes deviated substantially from the general trend. Construction costs were similar for plants from different habitats. This was mainly due to the positive correlation between an expensive class of compounds (proteins) and a cheap one (minerals).

Simultaneous consideration of initial construction cost and failure risk in practical design of critical hydraulic structures is a long-standing problem in water resources planning and management. Despite extensive efforts to effectively tackle this problem during recent decades, the traditional rather inefficient technique of return period approach still enjoys being the dominant technique in real-world projects. Accordingly, this article aims at developing an innovative evolutionarycomputation-based multi-objective model as a remedy to shortcomings of existing common methods. This simulation-optimization framework generates a series of uniformly distributed trade-off solutions which represent the compromise between competing objectives of construction cost and failure risk. Hydrologic and hydraulic uncertainties along with flood routing process are considered in the optimization process to provide a more complete picture of the problem. This approach is demonstrated and discussed for flood diversion system of Bakhtiari Dam in Iran and the Pareto optimal fronts are found for different combinations of uncertainties. The presented multi-objective approach can effectively enlarge the decision maker's scope to more efficiently determine the optimum design of the system.

To be affordable, a house must be designed and constructed to last; an approach to building that embraces sustainability principles. Energy efficient construction is proven to reduce the long-term costs of owning a house; it also improves building durability by decreasing the probability of moisture-related problems. When homeowners spend less on energy bills, they can better budget for maintenance and repair costs, which will again ensure that their house has longevity. While energy efficiency may modestly increase the up front construction costs, it will ensure that a house built today demonstrates value and will be affordable in the future.

This paper discusses the estimation cost in terms of effort spent on a software product (project). COCOMO II.2000 Model has been employed for estimating the effort of an embedded system project. This study has been made in a software services company, which is involved in software development for an embedded system, client-server and Internet environment. The embedded systems group is involved in developing software for major car manufacturers. This study is based on a sample of ten projects, of which eight are development projects and two are porting projects. The actual effort on the projects has been collected from the metrics database of the company. The Lines of code for the various projects have been enumerated using ''Code Count'' tool to achieve the logical source lines of code for each project. The standard questionnaire has been used to collect the required data to arrive at the various scale factors and effort multipliers. The calibration of the COCOMO (Constructive Cost Model) has been done through Natural Log approach and curve fitting approach. Statistical tools like MS-EXCEL 2000, SPSSv10, Curve Expert 1.3 and data fit have been used for this purpose. The study shows that the curve fitting approach yields better estimates of the model parameters. The calibration of COCOMO Model helps the company estimate the effort that is to be spent on the software development projects.

Lane closures during paving operations on rural two-lane roads usually restrict the continuity of paving operations, causing delay in paving time and thus affecting the production rates. This paper presents a simulation model that was developed to assess the impact of the different variables on paving operations under lane closure conditions. The model developed is a high-fidelity computer simulation that

Artificial neural networks have been used for simulation, modeling, and control purposes in many engineering applications as an alternative to conventional expert systems. Although neural networks usually do not reach the level of performance exhibited by expert systems, they do enjoy a tremendous advantage of very low construction costs.

Four different pilot-scale treatment units were constructed to compare the feasibility of treating domestic wastewater in the City of Heraklio, Crete, Greece: (a) a free water surface (FWS) wetland system, (b) a horizontal subsurface flow (HSF) wetland system, (c) a rotating biological contactor (RBC), and (d) a packed bed filter (PBF). All units operated in parallel at various hydraulic loading rates (HLR) ranging from 50% to 175% of designed operating HLR. The study was conducted during an 8 month period and showed that COD removal efficiency of HSF was comparable (N 75%) to that of RBC and PBF, whereas that of the FWS system was only 57%. Average nutrient removal efficiencies for FWS, HSF, RBC and PBF were 6%, 21%, 40% and 43%, respectively for total nitrogen and 21%, 39%, 41% and 42%, respectively for total phosphorus. Removals of total coliforms were lowest in FWS and PBF (1.3 log units) and higher in HSF and RBC (2.3 to 2.6 log units). HSF showed slightly lower but comparable effluent quality to that of RBC and PBF systems, but the construction cost and energy requirements for this system are significantly lower. Overall the final decision for the best non-conventional wastewater treatment system depends on the construction and operation cost, the area demand and the required quality of effluent.

The launch and deployment of picosatellites from the Stanford University OPAL microsatellite in February 2000 demonstrate the feasibility and practicability of a new age of space experimentation. Two of the six picosatellites deployed from OPAL were built by The Aerospace Corporation in El Segundo, CA and demonstrated new space testing of MEMS RF switches and intersatellite and ground communication with low power wireless radios. These picosatellites weighting less than one kilogram with dimensions of 4x3x1 inch were built as test platforms for DARPA and were constructed and delivered for flight in less than nine months.

Network physical links configuration is one of the most important problems of mobile communication network planning because it will determine the long-term performance and service quality of networks. In the 4G Radio Access Network (RAN) a new ring topology of physical links may be applied in contrast to RANs of current wireless systems. In this paper, the problem of the ring configuration of physical links from the viewpoint of minimum 4G RAN construction cost is considered. We formulate this problem as a combinatorial-optimization one and use dynamic programming principle for its solution. Software calculation results demonstrate the capability of our approach to determine the minimum-cost configuration.

""Part of each feasibility study of a food production plant is to make an estimation of the “future” investment costs in such a plant. In this document, three rapid investment cost estimation methods are explained: 1) the indexed 0.6 exponent method, in case your plant is “similar” to one of the 40 food plants, listed by Bartholomai; 2) the adapted Marouli method for complete food plants, if you only know the total production capacity of your plant, and 3) the adapted Marouli method for separate plant production sections, to be used if you have a plant flowsheet and you know the capacity of each of the main production sections of the food plant. Each of these 3 estimation methods can be executed manually, but calculation is rapid and simpler by using the 3 Excel worksheets, included in this document. Several worked examples explain the mathematics behind each of the 3 cost estimation methods; these examples should help to understand the basics of the calculations.
Usually, investment cost estimations are made for plants to be build in the near future. but are based on investment cost figures from the past, often with different production capacities. To convert past plant investment costs to future estimated plant costs, the Chemical Engineering Plant Cost Indices, from 1980 onward, are available, both as a table and as a graph. To convert plant production capacity from past to future capacity, the well-known 0.6 exponent rule is used.
Annex 1 discusses similar investment cost estimation methods for non-food plants, based on Perry’s (1985 and 1999) tables with past plant investment costs of many non-food factories.
""

Abstract Timber–concrete composite beams and slabs require interlayer connectors, which provide composite action in the cross-section. A range of mechanical connectors is available on the market with an extensive variety of stiffness and strength properties, which are fundamental ...

During the last few decades many developments in computer science, software programming and application production have been adopted by various engineering disciplines. These developments are mostly focusing on Artificial Intelligence Techniques. Therefore, a number of definitions are presented, which focus on the concept of Artificial Intelligence from different viewpoints. This paper reviews existing applications of Artificial Intelligence (A.I.) that facilitate cost management in civil engineering projects. An analysis of the Artificial Intelligence in its specific partial branches is presented. These branches or approaches contributed to the creation of a significant group of models that concern analysis, interpretation and prediction of various parameters. A list of selected, up to date models is provided, that concern cost management for civil engineering projects. The models are analyzed according to the activity, field of operation, input and output data and the methods and techniques they implent. It becomes clear that Artifial Intelligence will be the future essential tool for every engineer and it will lead to significant improvements in the construction sector.

Budgeting, bidding and planning of software project effort, time and cost are essential elements of any software development process. Massive size and complexity of now a day produced software systems cause a substantial risk for the development process. Inadequate and inefficient information about the size and complexity results in an ambiguous estimates that cause many losses. Project managers cannot adequately provide good estimate for both the effort and time needed. Thus, no clear release day to the market can be defined. This paper presents two new models for software effort estimation using fuzzy logic. One model is developed based on the famous COnstructive COst Model (COCOMO) and utilizes the Source Line Of Code (SLOC) as input variable to estimate the Effort (E); while the second model utilize the Inputs, Outputs, Files, and User Inquiries to estimate the Function Point (FP). The proposed fuzzy models show better estimation capabilities compared to other reported models in the literature and better assist the project manager in computing the software required development effort. The validation results are carried out using Albrecht data set.

Purpose -Labour usage represents one of the critical elements in the Malaysia construction industry due to severe shortage of local workers. This paper aims to present a construction performance comparison between conventional building systems and industrialised building systems (IBS). Design/methodology/approach -Data were obtained from 100 residential projects through a questionnaire survey in 2005. A total of 100 respondents participated in this study. Findings -Analysis of variance (ANOVA) results indicated that the actual labour productivity comparison between conventional building system and IBS was significantly different. Further, the comparison of crew size indicated that the conventional building system of 22 workers was significantly different from the IBS of 18 workers. Similarly, the cycle time of 17 days per house for conventional building system was found to be significantly different from the IBS of four days. However, the conventional building system was found to be insignificantly different from the IBS in term of structural construction cost. Originality/value -The results acquired from this study could be used by project planners for estimating labour input, control costs and project scheduling. Additionally, they could be used to determine the most appropriate structural building system for executing a construction project at the conceptual stage.

Current software cost estimation models, such as the 1981 Constructive Cost Model (COCOMO) for software cost estimation and its 1987 Ada COCOMO update, have been experiencing increasing difficulties in estimating the costs of software developed to new life cycle processes and capabilities. These include non-sequential and rapid-development process models; reuse-driven approaches involving commercial off-the-shelf (COTS) packages, re-engineering, applications composition, and applications generation capabilities; object-oriented approaches supported by distributed middleware; and software process maturity initiatives. This paper summarizes research in deriving a baseline COCOMO 2.0 model tailored to these new forms of software development, including rationale for the model decisions. The major new modeling capabilities of COCOMO 2.0 are a tailorable family of software sizing models, involving Object Points, Function Points, and Source Lines of Code; nonlinear models for software reuse and re-engineering; an exponentdriver approach for modeling relative software diseconomies of scale; and several additions, deletions and updates to previous COCOMO effort-multiplier cost drivers. This model is serving as a framework for an extensive current data collection and analysis effort to further refine and calibrate the model's estimation capabilities.

This paper disentangles the complexities of the commercial real estate market and provides a clear structure to understand the key determinants driving property market performance. There is a preference for using GDP, unemployment rate, and office (FIRE) employment as the main determinants of the space market (demand side); office floor stock, construction orders and vacancy rate (especially in the United States) as the property market (supply side) determinants in the office market. A regression model for Singapore's office property market for the period from June 1992 to December 2005 was constructed. The office rent equation was able to account for 72 per cent of variation in gross rent for the period June 1992 to December 2005. Changes in previous year vacancy rates, contemporaneous construction costs, prime lending rate (lagged 6 months) and contemporaneous office sector employment were identified as the key determinants in explaining the variation in office rents in the Central Region of Singapore.

Shape is an important consideration in green building design due to its significant impact on energy performance and construction costs. This paper presents a methodology to optimize building shapes in plan using the genetic algorithm. The building footprint is represented by a multi-sided polygon. Different geometrical representations for a polygon are considered and evaluated in terms of their potential problems such as epistasis, which occurs when one gene pair masks or modifies the expression of other gene pairs, and encoding isomorphism, which occurs when chromosomes with different binary strings map to the same solution in the design space. Two alternative representations are compared in terms of their impact on computational effectiveness and efficiency. An optimization model is established considering the shape-related variables and several other envelope-related design variables such as window ratios and overhangs. Life-cycle cost and life-cycle environmental impact are the two objective functions used to evaluate the performance of a green building design. A case study is presented where the shape of a typical floor of an office building defined by a pentagon is optimized with a multiobjective genetic algorithm.

This paper is a contribution to the study of tunnelling in difficult conditions, with attention paid to large time-dependent deformations, which may develop either during construction, causing instabilities of the tunnel heading and of the face, or during the service life of the tunnel. Under these circumstances the construction costs may rise due to the delays in excavation time, the stabilisation and heavy support measures that need be adopted. Following a review of characterisation and modelling of time-dependent behaviour in rock, the mechanical behaviour of Clay Shales (CS), a structurally complex formation of the Apennines (Italy), is described. Then, the key factors involved in the selection of the constitutive model for CS are identified. Two constitutive models are selected and discussed and their specific material parameters determined. A case study of a large size tunnel is presented where numerical modelling by the finite difference method is carried out. The results of modelling are compared with the monitoring data in terms of radial convergence of the tunnel and extrusion of the tunnel face.

لعل أول مطلب عند التفكير في إقامة مشروع معين هو التكاليف الخاصة بالمشروع  ، وذلك لمعرفة إمكانية القيام بالمشروع من عدمه و عمل دراسات الجدوى الاقتصادية له ، ولذلك فإن تكاليف إقامة أي مشروع تكون متعددة العناصر ويمثل الجزء الخاص بتكاليف البناء أحد العناصر الهامة الأساسية في إقامة كثير من المشروعات الاقتصادية ، ويعتبر العنصر الحرج للتكاليف في إقامة بعض المشروعات الخاصة بالإسكان وماشابه لذلك .




وعليه يكون من الضروري قبل البدء في إقامة مشروع جديد أو عمل تعديل في مشروع قائم بغرض الاستفادة منه في نشاط آخر أت يتم معرفة القيمة التقديرية لتكاليف البناء ولو بصورة تقريبية تساعد على اتخاذ القرار للبدء في إعداد الرسومات الهندسية من عدمه كما تستخدم هذه القيمة التقديرية في دراسات الجدوى التي تتم لاتخاذ القرار بشأن تنفيذ المشروع من عدمه .
أما التقدير التفصيلي لتكاليف انشاء المشروع فيكون ذلك بعد اتخاذ القرار والموافقة على تنفيذ المشروع وتكليف المهندسين المتخصصين في إعداد الرسومات الابتدائية التي يتم الموافقة عليها من المالك ثم يتم إعداد الرسومات التنفيذية التفصيلية ، والمواصفات الفنية التي تشمل الوصف الفني الدقيق للأعمال المطلوبة كجزء مكمل للتصميمات .
يتم عمل التقدير التفصيلي وذلك من حساب كميات بنود الأعمال الداخلة في تنفيذ المشروع عن طريق الاستعانة بالرسومات بأخذ المقاسات منها و المواصفات الموضوعة للبنود المختلفة ( وهو ما يسمى بالمقايسة ) وتستخدم هذه الكميات لعرضها على المقاولين لوضع أسعارهم عليها أو للتعاقد على أساسها لتنفيذ المشروع ، أم التكلفة الإجمالية النهائية للمشروع ، فيتم ذلك تباعاً أثناء تنفيذ المشروع بأخذ المقاسات من الطبيعة حتى نهاية المشروع وعمل الحساب الختامي ويسمى ذلك ( حصر الكميات من الطبيعة ) وعامة لتنفيذ مشروعات التشييد والبناء يتطلب الأمر المرور بعدة مراحل والتي سوف نتناولها بالتفصيل في هذا الكتاب ، والذي يعنى حقيقة بكيفية إعداد المواصفات الفنية للمشروع لكل تفاصيليها ، وكيفية القيام بالحصر لمعظم العناصر الانشائية و الكميات من خلال أمثلة وتطبيق على مشروع قائم ، وأتمنى من الله عزوجل أن أكون وفقت في طرح وتبسيط هذا المجال للقارئ وأن يسهل على القارئ فهمه وإدراكه جيدا .

Six storm-water best management practices ͑BMPs͒ for treating urban rainwater runoff were evaluated for cost and effectiveness in removing suspended sediments and total phosphorus. Construction and annual operating and maintenance ͑O and M͒ cost data were collected and analyzed for dry extended detention basins, wet basins, sand filters, constructed wetlands, bioretention filters, and infiltration trenches using literature that reported on existing storm-water BMP sites across the United States. After statistical analysis on historical values of inflation and bond yields, the annual O and M costs were converted to a present worth based on a 20-year life and added to the construction cost. The total present cost of each storm-water BMP with the 67% confidence interval was reported as a function of the water quality design volume, again with a 67% confidence interval. Finally, the mass of total suspended solids and total phosphorus removed over the 20-year life was estimated as a function of the water quality volume. For the six storm-water BMPs investigated, results show that, ignoring land costs, constructed wetlands have been the least expensive to construct and maintain if appropriate land is available. However, since wetlands typically require more land area to be effective, land acquisition costs may result in wetlands being significantly more expensive than other storm-water BMPs that require less area. The results can be used by planners and designers to estimate both the total cost of installing a storm-water BMP and the corresponding total suspended solids and total phosphorus removal.

บทคัดย่อ : งานออกแบบฐานรากและโครงสร้างทางด้านวิศวกรรมปฐพี ยังไม่มีความชัดเจนในเรื่องการกําหนดค่าอัตราส่วนความปลอดภัย โดยปกติทั่วไปมักจะใช้ค่าอัตราส่วนความปลอดภัยระหว่าง 1.2 - 4.0 ในการศึกษาวิจัยนี้มุ่งเน้นหาความสัมพันธ์ของข้อมูลชั้นดินอ่อน บริเวณ พื้นที่กรุงเทพมหานคร ซึ่งเป็นองค์ประกอบหลักที่ใช้ในการออกแบบสําหรับงานวิศวกรรมปฐพี โดยหลักการได้นําเอาทฤษฎีความน่าจะเป็น และการวิเคราะห์ข้อมูลพื้นฐาน โดยอาศัยการทดสอบทางด้านสถิติ รวมทั้งศึกษาความแปรปรวนจากปัจจัยต่างๆ,ระดับความเชื่อมั่น ,ตังบ่งชี้ความ เชื่อมั่น,การยอมรับความเสี่ยง และโอกาสการเกิดพังทลาย( Probability of Failure)ของโครงสร้างฐานรากในชั้นดินอ่อนในแต่ละระดับ ความสําคัญ(Individual limit state of performance function) การวิเคราะห์ความแปรปรวน (uncertainties) และ การวิเคราะห์ความเชื่อมั่น (reliabilities approach) โดยวิธี Monte Carlo simulation, FOSM., หรือ FORM., เป็นต้น ให้ผลลัพท์การกระจายตัวของค่าอัตราส่วนความ ปลอดภัย (a set of the partial safety factor) ในแต่ละ performance functions ผลของการศึกษาสามารถนําข้อมูลที่ได้ทําการวิเคราะห...

Synopsis Scattered case studies and anecdotal information form the "conventional wisdom" that building commissioning is highly cost-effective. Given that this belief has not been systematically or comprehensively documented, it is perhaps of no surprise that the most frequently cited barrier to widespread use of commissioning is decision-makers' lack of information pertaining to costs and associated savings. Designed as a "meta-analysis," this paper compiles and synthesizes published and unpublished data from real-world commissioning and retro-commissioning projects, establishing the largest available collection of standardized information on new and existing building commissioning experience in actual buildings. We analyze results from 224 buildings, representing 30.4 million square feet of commissioned space, across 21 states. We developed a detailed and uniform methodology for characterizing the results of projects and normalizing the data to maximize inte...

A computer program called HYDRA, that calculates the optimal design parameters of hydropower plants, is described here. This is done by utilizing the well known principle of optimising power losses and construction costs. Up to now it has only been possible to obtain local optima, due to the great complexity of the objective function. The best known example is optimisation of tunnel diameters. The weakness of local optimisation is the substantial risk of missing the true optimum. A new computer model is presented that uses an evolutionary method called Genetic Algorithm to find the global optimal project design by maximising the net profit of power sales. The model is calibrated against a theoretical example with an optimum that can be obtained by conventional mathematical methods. A case study is performed by comparing the design of an actual project to the optimal results of the model. The most interesting result is that while the model solution produces the same size of power pla...

This research spotlights the issue that decisions made at the early stages of building design have the greatest and impact on cost implications for construction and the building lifecycle. While the design of services (heating, ventilation and air-conditioning) constitutes a large part of the construction cost, they are traditionally not considered at the early stages of design. Methods such as

This paper is a contribution to the study of tunnelling in difficult conditions, with attention paid to large time-dependent deformations, which may develop either during construction, causing instabilities of the tunnel heading and of the face, or during the service life of the tunnel. Under these circumstances the construction costs may rise due to the delays in excavation time, the stabilisation and heavy support measures that need be adopted. Following a review of characterisation and modelling of time-dependent behaviour in rock, the mechanical behaviour of Clay Shales (CS), a structurally complex formation of the Apennines (Italy), is described. Then, the key factors involved in the selection of the constitutive model for CS are identified. Two constitutive models are selected and discussed and their specific material parameters determined. A case study of a large size tunnel is presented where numerical modelling by the finite difference method is carried out. The results of modelling are compared with the monitoring data in terms of radial convergence of the tunnel and extrusion of the tunnel face.

Providing adequate proper housing is one of Malaysian government agenda towards becoming a develop nation in Wawasan Kemakmuran Bersama 2030. Under previous Construction Industry Transformation Plan (CITP) 2015, the government aims to provide enough and comfortable residential to all citizen, and achieve a better standard of construction where prefabrication concept in housing replaces the conventional concept. The advantages of prefabrication concept are numerous including reducing the dependency on foreign labours, better quality, cost saving and speed. So long our local residentials have already familiar with conventional method, thus shifting into prefabricated concept is no easy task. Numerous efforts have been taken by Construction Industry Development Board of Malaysia (CIDB) and the government to ensure the prefabricated residential will become the preferred choice by developers. However, the uptake has been very slow and the target seem likely unachievable due to many reasons. Therefore, there is an urgency to know what are the difficulties that the industry facing in adopting prefabricated housing and what steps can be taken to overcome those problems. This paper discusses the barriers in implementing prefabricated concept in residential and the drivers that can speed up the application. The discussion based on published journals and articles that prioritize the views from all major players in prefabricated residential projects including contractors, developers, clients, consultants and prefabrication manufacturers and installers. This research contributes to the body of knowledge by revealing the true reason of why prefabricated housing is hard to be implemented, where the arguments combine the views from all major players. This study also provides steps to solve the problems taken from experience from other successful countries.

A study was conducted to stabilize low stiffness road surface material with high carbon fly ash. The non-cementitious Maryland fly ash was activated with another recycled material, lime kiln dust (LKD). California bearing ratio (CBR) and resilient modulus tests were conducted to determine the strength and stiffness, respectively, of the stabilized materials. Addition of LKD and curing of specimens generally increased CBR and summary resilient modulus (SM R ) and lowered plastic strains, whereas fly ash addition alone decreased the strength and stiffness due to the non-cementitious nature of the ash.

Using a panel of Major League Baseball team attendance data for the period 1950-2003, we determine that after controlling for team quality and other factors, a new modern era ballpark adds 27-36% to total attendance over a ten-year period and on average generates present-value stadium revenues of $133 million for the franchise. We further find that due to noncomplementarity between new stadiums and team success, team profits are maximized when an owner "pockets" increases in revenue rather than reinvesting in the on-field quality of the team.