Applications of Horizontal Characterization Techniques in Trenchless Construction

Horizontal site characterization technologies present a rapidly evolving alternative to traditional vertical site investigation methods for subsurface investigations of large diameter trenchless construction projects. A state-of-the-art review of horizontal site characterization tools, both currently available and under development, is presented. Additionally, a rational methodology for the selection and deployment of horizontal site investigation techniques in trenchless construction projects is also presented. The methodology enables the user to define and quantify the risks involved in a particular project, as well as to evaluate the degree to which these risks can be mitigated using various site characterization techniques. The proposed model is demonstrated using a working example. The paper concludes with a discussion of future trends in this exciting new field. The main conclusions drawn from this work are (1) adequate subsurface information is invaluable for underground construction; (2) site investigation programs of linear construction projects can be enhanced by horizontal characterization techniques; and (3) the availability of continuous and near-continuous subsurface information enables the utilization of new approaches for the analysis and representation of subsurface data.     

中国非开挖水平定向钻进装备与技术研究应用进展

从非开挖水平定向钻进（Horizontal directional drilling,HDD）装备技术、地下生命线工程的探测与信息化、双向对穿HDD技术、大口径HDD技术、HDD回拖力计算模型、地表变形与冒浆6个方面开展了文献调研工作,分析了HDD装备与技术研究应用进展:世界上最大回拖力（20000 kN）的电驱动钻机被设计并研发;电磁感应法被广泛用于既有生命线的空间探测,复杂干扰下的数据解析与精度提高仍是研究重点;基于三维数据,融合建筑信息模型、人工智能、大数据等技术,借鉴美国“811”体系,局部完成了地下生命线的信息化;采用对穿技术完成了长距离的地下生命线敷设;基于过程化的HDD工艺参数、设备参数和控制监测技术被大量应用,有效提升了应用中的风险识别能力;针对不同地层条件下的回拖力计算为设备选型提供了依据,并为HDD多学科融合研究提供了途径;复杂地质条件下的冒浆、卡钻等热点和难点也得到初步探索研究,构建了理论、实验和数值分析模式,为提高HDD的应用效率和质量提供了依据。综合国内外研究进展,进一步分析了HDD的发展趋势。      

Information Classification for Civil Engineering Projects by Uniclass

Since a well-established construction information classification system (CICS) can be an information center through the life cycle of a project, it is important to use a proper CICS for managing construction information. Construction Index∕Samarbetskommitten for Byggnadsfragor (CI∕SfB) has been used in various countries as one of the best among the earlier CICSs as well as Masterformat in North America. CI∕SfB, however, cannot represent many new construction technologies introduced during the 20 years that have passed since the last revision. Therefore, ISO developed a new CICS framework. Subsequently, the Construction Project Information Committee, including the Institution of Civil Engineers, developed the Uniclass system based on the ISO framework. Considering that Uniclass is intended to substitute for CI∕SfB and that each country needs international exchange of information by the ISO standard, it is necessary to analyze the organization of Uniclass. This study analyzed the practical adaptability of Uniclass compared to CI∕SfB and then suggested applicable illustrations with appropriate methodologies to improve the adaptability for civil engineering works. As a result, items classified in Uniclass gained a significant improvement for civil engineering projects compared to the existing CICSs, which have focused on architectural projects. The proposed methodologies will make the applicability of the CICS better by the improved scheme and by being consistent.     

Web-Centric Framework for Secure and Legally Binding Electronic Transactions in Large-Scale A∕E∕C Projects

Typical architecture∕engineering∕construction (A∕E∕C) projects are technically, socially, and economically complex in terms of planning, management, and execution. In order to conduct day-to-day operations within the project (allocating funds and resources), the organizations involved in large-scale A∕E∕C projects participate in contractual transactions. Currently, these transactions are primarily conducted in the form of paper-based contracts, but there is a need to automate them, leveraging the advancements in information technology. Due to the legal weight of these contracts, electronic transactions need to be as secure and binding as paper-based transactions; the absence of a framework to achieve this has prevented large-scale automation, in spite of the presence of a host of web-based project management services. In this paper, we address the security concerns in conducting legally binding electronic transactions in large-scale A∕E∕C projects by developing a framework for conducting secure and legally binding electronic transactions. We also discuss the issues related to the implementation of such a framework at the decade-long $13.6 billion Central Artery∕Third Harbor Tunnel Project in Boston, Massachusetts.     

Web-Based Decision Support Systems: Case Study inProject Delivery

The decentralized nature of the construction industry contributes to difficulties in the implementation and dissemination of project management-based decision tools. The majority of decision support systems (DSS) are contained in-house with private developers and users, or on researchers stand-alone computers and academic journals. Current World Wide Web technologies provide the appropriate means for large-scale implementation and continued development of DSS for the architectural, engineering, and construction community. This paper documents a DSS developed specifically for design∕build project selection among United States public sector agencies. The system, the Design∕Build Selector (DBS), is Web enabled, allowing for easy access and large-scale dissemination. Design∕build project procurement is rapidly expanding throughout public sector agencies in the United States construction industry. As public agencies turn to design∕build, appropriate project selection is a primary consideration affecting successful delivery. Prior to the implementation of DBS, there was no systematic or formalized method for selecting projects appropriate for design∕build. Since 1997, the Web site that houses the DBS has been visited by over 4,000 people, and the DBS tool has been used on 102 projects representing over $4.8 billion in construction. This paper reports on the application and potential for Web-based DSS in civil engineering. The architecture of the program, data collection, model weighting, and output interface are explained.     

Toward a New Paradigm: Simultaneous Use of Multiple Project Delivery Methods

Since World War II, the American Strategy for infrastructure procurement has evolved to rely primarily upon a single delivery method, design∕bid∕build. While this strategy was used to implement massive federal investment in highways, transit systems, and wastewater treatment, it has restricted state and local flexibility in aligning the procurement process to achieve best value for locally funded projects. The engineering, procurement, and construction community in the United States has now recognized the limitations of a procurement process designed to support a single delivery method. Change is coming, and the transition to a new process will challenge public owners in novel, but meaningful ways. This paper focuses upon shifting from the current paradigm toward a new model that supports simultaneous use of multiple project delivery methods. The discussion and frameworks provided are the result of a variety of research efforts by the Infrastructure Systems Development Research team at the Massachusetts Institute of Technology. Studies of the history of American Infrastructure, analyses of case studies across the country, development of decision support models for capital programming, and real applications to municipal infrastructure planning provide the underpinnings for the results and conclusions presented.     

Regional Alfalfa Yield, ETc, and Water Value in Western States

Alfalfa hay yield, yield-consumptive use ratio (Y∕ETc), and hay price across a range of rainfall and evapotranspiration conditions of the western states is evaluated to determine alfalfa hay water value or benefit. Included is a determination of long-term mean values and variability of yield, Y∕ETc ratios, and associated irrigation water values. These are compared with published hay water-use efficiencies, production, and water costs. Available rainfall, reference evapotranspiration ET0, hay yields, and prices for counties in Arizona (1987–1999), California (1998–1999), and Idaho (1993–1999) were used. Alfalfa hay Y∕ETc ratios decrease with increasing ETc, although their variability increases with increasing ETc. The greatest Y∕ETc ratios (16–17 kg∕ha-mm) and irrigation water values IW$ (IW$ = $2,800–$3,000∕ha-m), with relatively moderate variability, are associated with an irrigation water IW requirement of ～800 mm, reflecting a combination of relatively high hay values, ETc, and beneficial rain. Although this IW$ is twice that of water delivery prices below the California delta and is comparable with average municipal water costs of $4,000∕ha-m for large western cities, the average is nearly 1∕3.     

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.     

Alternative Delivery Approaches for Military Medical Construction Projects

Military medical construction projects take more than 10 years to complete, from the time the need for a new facility is identified until the building actually opens for occupancy. This time is often extended even further due to complications during the design and construction process. Furthermore, these projects often are completed well over their original budget. Although there are many reasons for this exorbitant amount of time and many causes for the budgetary problems, one of the major factors is the reliance on the traditional methods of a lump-sum contract and the design∕bid∕build project delivery approach. The writers illustrate how the use of alternative project delivery methods (specifically construction management and design∕build) can reduce the amount of time it takes to design and build a new military medical facility, as well as reduce the overall cost of the project. The advantages offered by these alternative delivery methods are set forth, and their applicability within the federal procurement process is discussed. Several recommendations are then given for using these methods for the design and construction of military medical facilities.     

A∕E∕C Teamwork: A Collaborative Design and Learning Space

This paper describes an ongoing effort focused on combined research and curriculum development for multidisciplinary, geographically distributed architecture∕engineering∕construction (A∕E∕C) teamwork. It presents a model for a distributed A∕E∕C learning environment and an Internet-based Web-mediated collaboration tool kit. The distributed learning environment includes six universities from Europe, Japan, and the United States. The tool kit is aimed to assist team members and owners (1) capture and share knowledge and information related to a specific project; (2) navigate through the archived knowledge and information; and (3) evaluate and explain the product's performance. The A∕E∕C course offered at Stanford University acts as a testbed for cutting-edge information technologies and a forum to teach new generations of professionals how to team up with practitioners from other disciplines and take advantage of information technology to produce a better, faster, more economical product. The paper presents new assessment metrics to monitor students' cross-disciplinary learning experience and track programmatic changes. The paper concludes with challenges and quandaries regarding the impact of information technologies on team performance and behavior.     

Nature and Extent of Domestic Construction Program Outsourcing

The sourcing of a construction program has always been a fluid process for many construction owners. A construction owner must balance the performance of all construction functions between internal staff and external service providers. Described herein are recent sourcing trends of construction programs identified through a survey of nonresidential construction owners. The survey data is representative of 170 respondents with varying demographic characteristics that account for about $72 billion in annual construction spending. Included are outsourcing trends of specific functions across the construction lifecycle and the sourcing strategy employed for each. A comparison of the outsourcing volume reported and the sourcing strategy employed is presented. A clear relationship between the amount of outsourcing and the sourcing strategy employed for the performance of construction is shown. The paper provides the academic community with new outsourcing data for construction lifecycle functions. It also provides contractors with new information about the current behavior of construction owners while providing owners with a better understanding of the relationship between sourcing and outsourcing.     

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.     

One Company's Experience with Design∕Build: Labor Cost Risk and Profit Potential

This paper offers the data from one construction company's experiences with design∕build. Specifically, the paper presents an analysis of the company's labor cost risk based on a case study of two similar projects. One project was a typical design∕bid∕build job and the other was a design∕build job. The design∕build project experienced consistently greater fluctuations in the labor cost. These fluctuations seem to indicate that it is very difficult to accurately estimate labor costs for design∕build projects, thus adding to the risk of such projects. The second half of the paper presents an account of this same company's overall profit experience with design∕build work. Profit margins were analyzed using three categories—design∕build versus non-design∕build, client-specific design∕build, and design∕build construction types. The design∕build projects' average profit margin was 3.5 percentage points greater than that for the non-design∕build work.     

Information Technology Planning Framework for Large-Scale Projects

New information technology developments continue to have a significant impact on large-scale architectural∕engineering∕construction (A∕E∕C) projects. However, the issue of whether A∕E∕C organizations are receiving adequate returns from their information technology (IT) investments remains an important managerial concern. Earlier work on financial models has concentrated on firm-wide strategies for maximizing the return of investments. Traditional financial models for measuring the value of information technology investments typically work well for static business strategies and single business scenarios. These models are inappropriate for large-scale A∕E∕C projects, which typically have multiple firms participating over a fixed project life cycle and proportionately splitting the cumulative benefits accrued over the project life cycle after their involvement on the project. To resolve these issues, the paper proposes a strategic planning framework based on IT diffusion for maximizing the value of investments in strategic capabilities. The essential steps in the strategic planning framework include environmental scan, internal scrutiny, IT diffusion analysis, and IT investment modeling. To demonstrate the framework and an integrated approach to IT investment planning, the paper presents a case study based on a large-scale A∕E∕C project.     

Management-Driven Integration

The fragmentation of the architecture∕engineering∕construction (A∕E∕C) industry creates increased demand for coordination and integration of project participants. This paper provides practitioners with an increased understanding of the importance of integration for project and company performance, and the integration mechanisms and barriers. The paper first provides a review of the literature on organizational theory, construction, and manufacturing, and identifies integration mechanisms and potential benefits. Then, the paper presents empirical evidence regarding the integration benefits that managers in construction firms identify, the mechanisms they use, and the reasons that prevent them from utilizing integration mechanisms. Finally, the paper identifies four managerial barriers to integration: need for front-end investments, difficulty to measure and distribute the benefits, reduced ability to utilize integration mechanisms across projects, and lack of skills and organizational culture that promote integration.     

Emerging Hybrid Practices in Construction Design Work: Role of Mixed Media

Information technologies are used across all stages of the construction process, and are crucial in the delivery of large projects. Drawing on detailed research on a construction megaproject, we take a practice-based approach to examining the practical and theoretical tensions between existing ways of working and the introduction of new coordination tools in this paper. We analyze the new hybrid practices that emerge, using insights from actor-network theory to articulate the delegation of actions to material and digital objects within ecologies of practice. The three vignettes that we discuss highlight this delegation of actions, the “plugging” and “patching” of ecologies occurring across media and the continual iterations of working practices between different types of media. By shifting the focus from tools to these wider ecologies of practice, the approach has important managerial implications for the stabilization of new technologies and practices and for managing technological change on large construction projects. We conclude with a discussion of new directions for research, oriented to further elaborating on the importance of the material in understanding change.     

Comparison of Technology Utilization and Benefits in Taiwanese and U.S. Industries

Lack of information regarding technology benefits along with uncertain competitive advantage from new technology have resulted in industry reluctance to implement new technologies. Three hundred and seven completed projects from across Taiwan and the United States have each been assessed for the levels of technology employed on 68 different common project work functions (WFs). In addition, the projects have been assessed for the levels of overall project cost- and schedule-performance attained. This paper reports on the details and findings of this study. Specifically, differences in technology usage between the Taiwanese and U.S. industries are analyzed. Project technology findings are presented by project phase and work function—both task automation-type work functions and integration-link WFs. Project success findings for the Taiwanese and U.S. industries are presented and comparisons across national boundaries are discussed. Findings from this study can provide information on the difference in technology usage and benefits between the Taiwanese and U.S. industries.     

Contractor Selection for Design∕Build Projects

As traditional construction procurement approaches are found to be inadequate in meeting the demands and challenges of recent times, alternative procurement routes such as through management contracting or build-operate-transfer are increasingly being adopted. Although design∕build is one of the more popular alternative procurement methods that also has a long history, it does not appear to have well-established contractor selection procedures. This paper focuses on developing a model for contractor prequalification and bid evaluation in design∕build projects. For this purpose, it presents a comparative overview of some international practices in the design∕build contractor selection process. The overall objective is to identify the core aspects of selecting a suitable bidder in order to achieve the best “value for money.” The strengths and weaknesses of current practices of contractor selection are highlighted while identifying some of the best practices followed in design∕build projects by various clients.     

Bed-Form Geometry in Sand-Bed Flows

A new method is proposed for predicting relative bed-form height h∕d in sand-bed flows. The proposed method is based on the concept of relating energy loss due to form drag to the head loss across a sudden expansion in open channel flows. A unique feature of the proposed method is that it can be applied to various bed forms, i.e., ripples, dunes, antidunes∕standing waves, and transitional bed regimes that occur in alluvial flows. The relation thus developed was applied to a large number (251 flows, 14 different data sets) of laboratory and river data, and was found to give good agreement with the observed h∕d values. In a comparison of prediction accuracies with seven existing relationships, the proposed method was found to give significantly better agreements with the observed data. Future improvements in the prediction of h∕d will depend on improved formulations of the two parameters incorporated in the present relation, i.e., energy loss coefficient K, and the relative bed-form length L∕d for various bed configurations. More research is needed to develop better formulations for these parameters.     

包钢白云西矿矿浆管道工程新技术应用

文章主要阐述了白云鄂博矿山铁精矿浆管道和供水管道工程施工过程中应用的新技术,特别是冷弯管制作技术,冬季焊接施工技术,矿浆输送管道施工和吊装技术,矿浆输送管道清管、测径、试压技术及浆体输送管道线路测量施工技术的推广应用,为今后类似工程施工积累了宝贵的经验。