Geotechnical Investigation Strategies for Lunar Base

Geotechnical characterization of potential lunar sites will be a critical part of the planning and design process. The strategies used to conduct a geotechnical investigation will be dictated by the specific needs of the lunar base, the unique environment of the lunar surface, and general character of the lunar soils and rocks. This paper outlines some of the types of geotechnical information that will be important and identifies some of the more promising strategies which might be used to obtain such information in the lunar environment. Some of the most important geotechnical information for planning and site development will be related to construction in the lunar soil. In addition to construction concerns, geotechnical data for foundation design (or verification of predesigned foundations) will be needed. The geotechnical site‐characterization work should include geophysical techniques, supplemented by conventional mechanical boring and testing only to the degree necessary to correlate geophysical measurements with conventional soil properties and to investigate anomalies. Equipment used for geotechnical site characterization will also serve for mineralogical exploration. Several techniques for geotechnical investigation that may provide very useful information in an expedient manner are described. Geophysical methods include seismic and electromagnetic methods, including seismic surveys that utilize surface waves. Electromagnetic methods such as ground‐penetrating radar are fast, efficient methods for mapping the subsurface, although these techniques do not measure soil characteristics that can readily be correlated with engineering properties. Seismic methods provide information that may correlate with soil strength, compressibility, and excavatability. In‐situ physical testing will likely include penetration testing for direct physical measurement of lunar soil behavior.     

Utilization of Trenchless Construction Methods by Canadian Municipalities

Trenchless technology is an emerging area of construction involving innovative methods, materials, and equipment used for the installation of new and the rehabilitation or replacement of existing underground infrastructure with minimal or no need for open cut excavation. This technology provides an alternative to traditional methods of open trenching construction, which is often associated with major disruptions to surface activities. The results of a survey of trenchless construction methods in Canada are presented in this paper. The survey, which was sent to 87 municipalities across Canada, provides an indication of current and future trends in the application of trenchless construction technologies in the municipal arena including type and frequency of technologies employed, percentage of projects that employed trenchless technologies, and contractor selection methods. The survey results indicate that trenchless technology is gaining increasing popularity among municipal engineers across Canada. The percentage of all municipal projects utilizing trenchless construction methods has grown over the past 5 years by 180% (new construction) and 270% (rehabilitation). The survey also revealed that the typical Canadian municipality spends $29.68∕capita on new construction of municipal service lines and $18.21∕capita on rehabilitation of existing lines.     

Experience from Two Resistivity Inversion Techniques Applied in Three Cases of Geotechnical Site Investigation

The combination of in situ geotechnical testing and continuously measured geophysical data can be a powerful tool in geotechnical site investigation. In two cases from Sweden and one case from Denmark electric resistivity surveys are used successfully in geotechnical site investigations. The main contribution of resistivity results is the possibility to interpret continuous geological models. An improved methodology combines two-dimensional (2D) smooth inversion and 2D laterally constrained inversion (2D-LCI) to significantly increase interpretability. The 2D smooth inversion has high horizontal resolution and 2D-LCI high vertical resolution. The possibility to add a priori information from, for example, drill log data to constrain the 2D-LCI increases the confidence in the inverted model and limits ambiguity. In a site investigation for a railway trench in southern Sweden a geotechnical data set is used as a priori data to increase the reliability of the inversion of the resistivity data. From this combined survey a complex Quaternary geology is described in detail. A slope stability study from south of Stockholm, Sweden, employed resistivity data together with refraction seismic and geotechnical drill log data. The result gives necessary geometrical information for the important geological units, for example for stability calculations. Both these surveys were performed with a multielectrode system. In the third case a pulled array resistivity survey was used to map the uppermost 15–20?m to estimate the distribution of the geological formations for freeway construction in Denmark. The result enables a more accurate estimate of the total freeway construction costs.     

Risk-Based Safety Impact Assessment Methodology for Underground Construction Projects in Korea

Safety of construction projects may be affected by various factors such as types and scale of projects, construction methods, safety management procedure, climate, site conditions, etc. Among them is the quality of design in relation to safety. Presently, however, designers typically are not involved in construction safety. They are often uncertain of their responsibilities in relation to construction safety and fail to be responsible for avoiding or reducing safety-related risks. In this study, the concept of safety impact assessment to achieve “design-for-safety” in the design phase is introduced. For this purpose, a safety impact assessment model was devised, and a methodology using the risk-based safety impact assessment approach for open-cut type underground construction projects in Korea is suggested. The suggested methodology includes a safety information survey, classification of safety impact factors caused by design and construction, and quantitative estimation of magnitude and frequency of safety impact factors. A checklist which can be easily used for assessing the safety performance of design products is also proposed. A real-world case study on the safety impact assessment of a subway construction project in Korea is also provided in the paper.     

Risk Assessment Methodology for Underground Construction Projects

This paper presents a risk assessment methodology for underground construction projects. A formalized procedure and associated tools were developed to assess and manage the risks involved in underground construction. The suggested risk assessment procedure is composed of four steps of identifying, analyzing, evaluating, and managing the risks inherent in construction projects. The main tool of the proposed risk assessment methodology is the risk analysis software. The risk analysis software is built upon an uncertainty model based on fuzzy concept. The fuzzy-based uncertainty model is designed to consider the uncertainty range that represents the degree of uncertainties involved in both (1) probabilistic parameter estimates and (2) subjective judgments. Other tools developed in this study include the survey sheets for collecting risk-related information and the detail check sheets for risk identification and analysis. The paper finally discusses a detailed case study of the developed risk assessment methodology performed for a subway construction project in Korea.     

Soil Penetration Modeling in Microtunneling Projects

As the need for utility service line replacement or repairs with minimum disruption to the surface have increased, so has the demand for trenchless excavation methods, in particular, microtunneling. Microtunneling is a trenchless technique that is used to install new pipelines. Microtunneling can be applied in gravity and pressure lines, permanent ducts for cables, and crossings under rails or roads. When bidding a microtunneling project, the main concern of microtunneling contractors is predicting the underground behavior of the machine. In other words, the productivity of microtunneling is the key to profit in microtunneling projects. Contractors generally predict approximate productivity based on experience, which risks cost estimation accuracy for microtunneling projects. Contractors lack a productivity model that helps them to predict driving time. This paper is a part of a series of papers covering the productivity of microtunneling projects. This paper focuses on predicting the penetration time of the microtunneling machine.     

Modeling the Effect of Subjective Factors on Productivity of Trenchless Technology Application to Buried Infrastructure Systems

Trenchless technology (TT) includes a large family of methods utilized for installing and rehabilitating underground utility systems with minimal surface disruption and destruction resulting from conventional excavation. Productivity of TT techniques is affected by a number of subjective factors that need to be evaluated. A productivity index (PI) model is developed in order to represent this subjective effect in refining productivity assessment. The analytic hierarchy process and fuzzy logic are used to develop the proposed PI model that relies on the actual performance of 12 subfactors under three main categories: management, environmental, and physical conditions. The developed PI model resulted in PI equal to 0.7323 and 0.7251 for microtunneling and horizontal directional drilling (HDD) projects, respectively. Multiattribute decision support system software is developed to determine the PI for a specific TT technique using Visual Basic. The PI model is tested, which shows reasonable results. This research is relevant to both industry practitioners and researchers. It provides practitioners with a model that justifies their productivity calculation by quantifying subjective factors effect, which will affect their schedule and cost estimation for trenchless projects. In addition, it provides researchers with the development methodology for the PI model.     

SERC—A Model for Estimating Construction Inputs

One of the main problems in the process of design and management of construction projects is obtaining accurate information for preliminary estimates. This information is crucial for the development of integrated systems for construction management because of the relationship between construction input data and subjects such as estimating, cost control, scheduling, resource management, etc. Existing methods for estimating input that originated in industrial engineering are inadequate for the unique conditions of the construction industry. The model described in this paper applies statistical analysis of data from past projects, and enables the user to estimate the data needed for the construction of a new project. The model is based on the following components: Project items and their quantities; inputs needed to produce those items; and factors that affect inputs of a specific project. The model equation was calculated using multiple regression techniques. The paper concludes with a case study of a construction input configuration for a concrete structure.     

Productivity and Cost Regression Models for Pile Construction

The estimating process of pile construction productivity and cost is intricated because of several factors: unseen subsurface obstacles; lack of contractor experience; site planning; and pile equipment maintainability. This study intends to assess cycle time, productivity, and cost for pile construction considering the effect of the above factors using regression technique. Data were collected through designated questionnaires, site interviews, and telephone calls to experts in different construction companies. Many variables have been considered in the pile construction process. Seven regression linear models have been designed and validated to assess productivity, cycle time, and cost. Consequently, three sets of charts have been developed based upon the validated models to provide the decision maker with a solid planning, scheduling, and control tool for pile construction projects. This research is relevant to both industry practitioners and researchers. It provides sets of charts and models for practitioners’ usage to schedule and price out pile construction projects. In addition, it provides the researchers with the methodology of designating regression models for the pile construction process, its limitations, and future suggestions.     

Generic Methodology for Analyzing Delay Claims

It is common for a construction project to encounter delays. There are several reasons that can contribute to delaying a project. Analyzing the various causes that contribute to a project's delay is an important task to resolving it. Determining, in a scientific manner, the impact, timing, and the contributing effect of each of those causes to the overall delay should assist in helping the parties settle the delay without litigation. Project participants are becoming more aware of the high costs and risks associated with delay claims and their litigation. Thus, the construction industry needs to develop methodologies and techniques to prevent and more efficiently resolve delay claims. While many practitioners have been following some kind of a methodology for analyzing delay claims, a written exposition of such a methodology is not widely available in the literature. Thus, this paper presents a written exposition of a generic methodology for analyzing delay claims. This methodology has been developed and successfully used, by the writer, in various projects to resolve delay claims. The developed methodology will be illustrated through its application in those projects. Moreover, this methodology shows that while there are several techniques for analyzing delay claims, very few of these can be considered adequate. The use of such an adequate technique is a key in obtaining a fair allocation of the delay responsibility. This paper's methodology utilizes one of these few adequate techniques for analyzing delay claims.     

Financial Viability Analysis and Capital Structure Optimization in Privatized Public Infrastructure Projects

Numerous public infrastructure projects have been privatized worldwide, where responsibilities, risks, and rewards are substantially reallocated between pubic and private sectors. The financial evaluation of a privatized infrastructure project is complex and challenging because of the risks and uncertainties due to the large size, long contract duration, nonrecourse financing, multiple project participants with different motives and interest, and the complexity of the contractual arrangements. Improved financial engineering techniques are required to overcome the limitations of traditional financial analysis techniques in addressing risks and uncertainties. This paper develops a methodology for capital structure optimization and financial viability analysis that reflects the characteristics of project financing, incorporates simulation and financial engineering techniques, and aims for win–win results for both public and private sectors. This quantitative methodology defines the capital structure of a privatized project in four dimensions, examines different project participants’ perspectives of the capital structure, optimizes the capital structure, and evaluates the project’s financial viability when it is under construction risk, bankruptcy risk and various economic risks (that are dealt with as stochastic variables), and is subject to other constraints imposed by different project participants. This methodology also evaluates the impact of governmental guarantees and supports, and addresses the issue of the equity holders’ commitment to project success by initiating the concepts of equity at project risks, value of governmental loan guarantee, and project bankrupt probability during construction. A framework and a solution algorithm are provided for this proposed methodology. These research outputs will significantly facilitate both public and private sector in evaluating a privatized project’s financial viability and collectively determining an optimal capital structure that safeguards their respective interests.     

Safety Risk Identification and Assessment for Beijing Olympic Venues Construction

New technologies, new materials, and innovative designs have been extensively adopted in Beijing Olympic venues construction. The extreme requirements for time deadline and competition function expose the venues construction to high risks. These risks would potentially bring negative impacts on the site safety performance. Meanwhile, there is a lack of systematic management for safety risks in China’s construction industry, especially for large projects such as the Beijing Olympic venues construction. This paper identifies and assesses safety risk factors inherent in Beijing Olympic venues construction with the involvement of 27 experienced and highly respected experts from government agencies, the construction industry, and academe through brainstorming, workshop discussions, and questionnaire surveys. The finding reveals that more than half of the critical safety risk factors are from contractors and subcontractors such as: lack of emergency response plan and measures; workers’ unsafe operation, and contractors ignoring safety under schedule pressure. Based on these critical safety risks, a risk register is composed and a model is developed in application of the analytic hierarchy process to assess the status of risks on site safety. The model has been attempted in two Olympic venue projects under construction and the validity has been approved. The risk checklist, register, and assessment model developed in the paper were integrated into the risk management system that has been used for Beijing Olympic venues construction.     

Managing Construction Projects Using the Advanced Programmatic Risk Analysis and Management Model

Risk management is an important part of construction management, yet the risk-based decision support tools available to construction managers fail to adequately address risks relating to cost, schedule, and quality together in a coherent framework. This paper demonstrates the usefulness of the Advanced Programmatic Risk Analysis and Management Model (APRAM) originally developed for the aerospace industry, for managing schedule, cost, and quality risks in the construction industry. The usefulness of APRAM for construction projects is demonstrated by implementing APRAM for an example based on an actual building construction project and comparing the results with other risk analysis techniques. The results show that APRAM simultaneously addresses cost, schedule, and quality risk together in a coherent, probabilistic framework that provides the information needed to support decision making in allocating scarce project resources.     

Construction Risks: Single versus Portfolio Insurance

Risks and uncertainties are naturally inherent in the construction industry and negatively affect contracting parties and executed projects. This paper explores the possibility of insuring against construction risks, which are beyond the control of contractors and not covered by surety policies, through single and portfolio insurance strategies. Accordingly, the writers programmed Iman and Conover’s bootstrapping method for inducing correlations using Microsoft Excel and consequently, developed a technique for pricing insurance premiums as an exotic option using Monte Carlo simulation. The aforementioned methodology was applied on a data set of five defined risks that were collected from small, medium, and large scale projects in California. Pursuant to this study, the calculated premiums for insuring against the defined risks are in line with the premiums available in market for other insurance policies. Moreover, the estimated premium for the proposed portfolio insurance product is more advantageous to contractors in both risk coverage and cost because it is well below the estimated premiums for single insurance products covering individual risks. It is foreseen that this research could open horizons for new construction related insurance products, which would significantly contribute to the efficiency of the risk management process in the construction industry.     

Political, Economic, and Legal Risks Faced in International Projects: Case Study of Vietnam

The aim of this research is to investigate the political, economic, and legal (PEL) risks faced by foreign firms when undertaking construction projects in Vietnam. The specific objectives are to investigate the types of PEL risks faced and the risk response techniques adopted. The data collection instrument was a questionnaire with open ended questions. The data collection method was in-depth face to face interviews with 18 experts from France, Hong Kong, Malaysia, Singapore, and the United States who have managed construction projects in Vietnam. The major risks faced include corruption, termination of public projects, bureaucratic administrative system to obtain permits and approvals, changing and inconsistent regulations, inadequate legal framework, fluctuation of exchange, and interest and inflation rates. Ways to respond to these risks are recommended by the experts. Foreign firms undertaking construction projects in Vietnam may make use of these findings to identify their PEL risks and determine the appropriate risk response measures to give their projects a higher chance of success.     

Multiple Simulation Analysis for Probabilistic Cost and Schedule Integration

One of the major goals of the construction industry today is the quantification and minimization of the risk associated with construction engineering performance. When specifically considering the planning of construction projects, one way to control risk is through the development of reliable project cost estimates and schedules. Two techniques available for achieving this goal are range estimating and probabilistic scheduling. This paper looks at the integration of these techniques as a means of further controlling the risk inherent in the undertaking of construction projects. Least-squares linear regression is first considered as a means of relating the data obtained from the application of these techniques. However, because of various limitations, the application of linear regression was not considered the most appropriate means of relating the results of range estimating and probabilistic scheduling. Integration of these techniques was, therefore, achieved through the development of a new procedure called the multiple simulation analysis technique. This new procedure combines the results of range estimating and probabilistic scheduling in order to quantify the relationship existing between them. Having the ability to accurately quantify this relationship enables the selection of high percentile level values for the project cost estimate and schedule simultaneously.     

Bootstrap Technique for Risk Analysis with Interval Numbers in Bridge Construction Projects

Bridges are principal and vital transportation structures. If risk management is not considered in bridge construction projects, objectives cannot be delivered on time, on budget, or with suitable quality results. Risk data set sizes and experts’ judgments are not usually sufficient for analyzing significant risks in bridge construction projects; moreover, the statistical distributions for risk parameter estimates are usually unknown. Standard parametric statistical techniques cannot provide appropriate solutions for cases with small data sets or unknown distributions. This paper proposes a new hybrid approach by using a nonparametric resampling technique and interval computations for risk analysis, in particular, for bridge construction projects. Bootstrap techniques produce more accurate inferences for comparing parametric techniques and are an alternative when the underlying parametric assumptions are not considered. Increasingly, because of the complexity and uncertainty in decision making at bridge projects, it is easier or more natural to provide interval values for parts or all of decision-making judgments. Furthermore, the goal of reducing standard deviations for both risk probability and risk impact compared with the conventional approach is another conclusion of this paper. The proposed approach is applied to a case in Iran to show the validity of the approach.     

Fuzzy Analytical Hierarchy Process Risk Assessment Approach for Joint Venture Construction Projects in China

Research and practice show that construction joint venture (JV) activities in China are opportunities that can bring potential benefits but at the same time may generate many risks. While research has studied these risks and presented useful advice for managing individual risks, the methodologies used to analyze the risks were mainly qualitatively based, and there is a gap in using the quantitative method that can integrate a risk expert’s knowledge to assess the risks associated with JV projects. This paper sets up a hierarchy structure of the risks and then develops a fuzzy analytical hierarchy process (AHP) model for the appraisal of the risk environment pertaining to the JVs to support the rational decision making of project stakeholders. An empirical case study is used to demonstrate the application of the proposed fuzzy AHP model. It is concluded that the fuzzy AHP model is effective in tackling the risks involved in JV projects. The information presented in this paper should be shown to all parties considering JV business opportunities in China, and the proposed approach should be applicable to the research and analysis of risks associated with any type of construction projects.     

Horizontal Directional Drilling: Profile of an Emerging Industry

Perhaps the fastest growing segment in the underground trenchless construction industry is horizontal directional drilling (HDD). Currently, in North America alone, there are 17 manufacturers of HDD rigs and accessories and thousands of horizontal drilling rigs that are owned and operated by several hundred dedicated HDD contractors as well as utility companies and large pipeline outfits. Applications of HDD span across the civil engineering spectrum from mineral and oil exploration to the installation of telecommunication cables. An industry survey was conducted to gain a better understanding of this multibillion dollar industry, which is relatively unfamiliar to many in the construction sector. This paper presents the results obtained from analyzing 49 survey responses from HDD contractors in the United States and Canada. Topics investigated include company profile (e.g., annual volume, areas of activities); type of projects performed (e.g., applications, value, duration, type of product installed), and bidding and estimating practices (e.g., productivity values in various formations, cost of installation), Current and future trends in the industry are identified and discussed.