Probabilistic prediction of expected ground condition and construction time and costs in road tunnels

Ground condition and construction （excavation and support） time and costs are the key factors in decision-making during planning and design phases of a tunnel project. An innovative methodology for probabilistic estimation of ground condition and construction time and costs is proposed, which is an integration of the ground prediction approach based on Markov process, and the time and cost variance analysis based on Monte-Carlo （MC） simulation. The former provides the probabilistic description of ground classification along tunnel alignment according to the geological information revealed from geological profile and boreholes. The latter provides the probabilistic description of the expected construction time and costs for each operation according to the survey feedbacks from experts. Then an engineering application to Hamro tunnel is presented to demonstrate how the ground condition and the construction time and costs are estimated in a probabilistic way. In most items, in order to estimate the data needed for this methodology, a number of questionnaires are distributed among the tunneling experts and finally the mean values of the respondents are applied. These facilitate both the owners and the contractors to be aware of the risk that they should carry before construction, and are useful for both tendering and bidding.

Comparison of School Building Construction Costs Estimation Methods Using Regression Analysis, Neural Network, and Support Vector Machine

Accurate cost estimation at the early stage of a construction project is key factor in a project’s success. But it is difficult to quickly and accurately estimate construction costs at the planning stage, when drawings, documentation and the like are still incomplete. As such, various techniques have been applied to accurately estimate construction costs at an early stage, when project information is limited. While the various techniques have their pros and cons, there has been little effort made to determine the best technique in terms of cost estimating performance. The objective of this research is to compare the accuracy of three estimating techniques (regression analysis (RA), neural network (NN), and support vector machine techniques (SVM)) by performing estimations of construction costs. By comparing the accuracy of these techniques using historical cost data, it was found that NN model showed more accurate estimation results than the RA and SVM models. Consequently, it is determined that NN model is most suitable for estimating the cost of school building projects.

A Review of Deepwater Pipeline Construction in the U.S. Gulf of Mexico-Contracts, Cost, and Installation Methods

The offshore pipeline network in the U.S. Gulf of Mexico is the largest and most transparent system in the world. A review of deepwater projects in the region provides insight into construction cost and installation methods and the evolution of contract strategies. Pipeline projects are identified as export systems, infield flowline systems, and combined export and infield systems, and three dozen deepwater pipeline installations from 1980–2014 are described based on Offshore Technology Conference(OTC) and Society of Petroleum Engineers(SPE) industry publications and press release data. Export lines and infield flowlines are equally represented and many projects used a combination of J-lay, S-lay and reel methods with rigid steel, flexible line, and pipe-in-pipe systems. The average 2014 inflation-adjusted cost for pipeline projects based on OTC/SPE publications was $2.76 million/mi and ranged from $520 000/mi to $12.94 million/mi. High cost pipelines tend to be short segments or specialized pipeline. Excluding the two cost endpoints, the majority of projects ranged from $1 to $6 million/mi. The average inflation-adjusted cost to install deepwater pipelines in the U.S. Gulf of Mexico based on available public data is estimated at $3.1 million/mi.

Leaf Construction Cost and Related Ecophysiological Parameters of Rice Crop and Its Important Weeds

To understand the reason for the success of weeds,we investigated the energetic cost of leaf construction,and certain ecophysiological traits of rice and its dominant weeds.On physiological basis among all weeds,Caesulia axillaris Roxburgh was found to be the most serious,followed by Echinochloa cruss-galli L.Beauv and Echinochloa colonum L.Link,while Fimbristylis miliaceae L.Vahl and Cyperus iria L.were moderate weeds of the rice fields.C.axillaris had the lowest leaf construction cost （LCC） both on a mass basis （1.15 g/g） and on a unit area basis （22.93 g/m2）.Comparatively higher specific leaf area,photosynthetic rate,photosynthetic nitrogen use efficiency,leaf area ratio and leaf area index provided C.axillaris with further competitive advantage.Low LCC suggests that weeds utilize carbon resource more efficiently than the crop and potentially spend the saved energy on other competitive strategies viz.seed production,biomass production and high relative growth rate,which results in low crop yield and increase in weed seed bank.

An Exploratory Study into Social Cost Considerations in Ghanaian Construction Industry

Construction causative nuisances, inconveniences, interferences and disruptions to the routine economic and social life patterns of adjacent or neighboring communities are referred to as social cost. This study explores the understanding and level of consideration of social cost by construction professionals in Ghana. Relevant literature sources are reviewed to define, rationalize and classify social cost. The study used the survey approach with a set of questionnaires addressed to construction contractors and professionals to gather the data. It was realized that not much consideration is given to social cost at the tender stage of the construction process. The five factors hindering social cost inclusion in tendering are “difficulty in allocating social costs”, “governmental interferences”, “lack of historical data”, “lack of appreciation of social costs” and “low stakeholder agitation”. The paper advocated for integration of social cost into the tendering process. The study will serve as a foundation to design a social cost assessment system at the pre-contract stage.

Control and Management of Construction Project Cost

Project cost can control the input in construction project and improve economic benefits of construction enterprises,so it is an important section of construction engineering.Reasonable control and management of project cost is the principle that building units must obey in the whole process of project,particularly in the construction stage,so it is extremely important to control and manage the project cost.This paper first analyzed possible causes for the unreasonable cost of construction projects,and put forward pertinent strategies for the control and management of construction project cost.

Construction Management and Cost Control of Landscaping Projects

Uniqueness of landscaping projects was analyzed,and cost was regarded as an important index evaluating performance of landscaping construction enterprises. Based on reviewing limitation of cost control on landscaping construction enterprises,enhancing construction management,controlling cost reasonably,and reducing project cost were proposed as the foundation and core content of enterprise cost management,and also the key to successful project management.By combining with design practices,suggestions for enhancing construction management of landscaping project,controlling cost and improving profits were given.

Method for Estimating of Construction Cost of a Building Based on Previous Experiences

In a real estate project, the estimated cost of construction and the revenues generally represent together the most important values of its feasibility study. When a decision of undertaking a project is made, often there are few definitions of what is about to be constructed, and frequently not enough to ensure the accuracy of the estimated costs. Considering a global tendency on reducing margins of return over the real estate markets, slight variations of the construction cost can jeopardize the success of the whole real estate enterprise and even the financial stability of the builder or of the developer. This article aims at presenting a method of estimating the building construction costs applicable at the stage of feasibility studies, being able to provide acceptable errors.

Representing the Knowledge of Public Construction Project Cost Estimator by Using Rule-Based Method

Despite the presence of various construction project cost estimate softwares, human experience and knowledge cannot be disregarded. This fact has been proven in practice, where the success of construction cost estimate process is mainly based on knowledge of human estimator. The main question concerns what human knowledge determines the success of the construction cost estimation process. To address this question we have applied Delphi technique and the output is eleven factors that are enough to precisely represent construction cost estimator knowledge. Then we have used First Order Logic (FOL) to represent these factors in terms of predicates and rules. These FOL rules could be used for evaluating construction cost estimator knowledge in five classes: fail, pass, acceptable, good, and very good. As a validation process we have done experiments using history data and the results have proved the accuracy of our proposed method.

Construction economic cost management under the market economy

Currently, how to further improve and perfect construction economic cost management,minimizing construction economic management cost and construction investment of the enterprise have become the important content for the daily management of construction enterprise managers. This article focuses on the construction economy under the conditions of market economy cost management, analyses related concepts and existing questions, and proposes targeted recommendations of the problem.

Research on Cost Overrun Risk of Construction Phase of Vietnam Highway International Contracting Project

Recently, the highway construction projects increase rapidly in Vietnam and most of them are international contracting projects. It results serious negative influence on the local government and enterprises that the common cost overrun of projects, and the risk factors of it is different in the different countries, different stages and projects types. So in this paper, we generate an evaluation index system of highway construction projects cost overrun risk in Vietnam in the perspective of different project participants, and also evaluate the effects of these factors in method of regression analysis. The empirical results confirmed 7 main factors that have aggravated cost overrun risk in construction stages, e.g. survey and design scheme risk. In final, the corresponding suggestions are proposed to reduce the project cost overrun risk.