146 results
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2. ASCE AWARDS BASED ON MERITORIOUS PAPERS.
- Subjects
CIVIL engineering ,STRUCTURAL engineering ,ENGINEERING ,AWARDS ,ENGINEERS - Abstract
Reports that the American Society of Civil Engineers (ASCE) and the Structural Engineering Institute (SEI) are looking for nominations for the 2006 ASCE and SEI Awards. Objective of the ASCE and SEI Honors and Awards Programs; ASCE awards based on meritorious papers; SEI awards.
- Published
- 2005
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- View/download PDF
3. Recent Development of 3D-Printing Technology in Construction Engineering.
- Author
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Akman, Arabella and Sadhu, Ayan
- Subjects
THREE-dimensional printing ,STRUCTURAL engineering ,STRUCTURAL engineers ,ENGINEERING ,CIVIL engineering ,CIVIL engineers - Abstract
The current construction industry for civil and structural engineering is considered to be one of the growing industries in the world. With the push toward a more digitized industry, emerging trends such as additive manufacturing and the use of three-dimensional (3D) printing technology, along with consumer demand, are resulting in automated development with multiple benefits. Successful applications for small-scale construction projects that have implemented 3D printing have shown improvements in cost, production time, and design freedom and complexity. However, for large-scale applications, there are various limitations and factors hindering the adoption of additive manufacturing technologies. In this paper, a systematic literature survey of recent 3D printing technologies was conducted specific to the area of construction engineering, and the various techniques, materials, software, and technical and nontechnical aspects were analyzed. The key applications and their benefits are outlined, and their potential for large-scale applications is articulated. Future research areas for these components are suggested to strengthen the technical readiness and feasibility of adopting 3D printing technology in construction engineering and industries. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Water Resource Engineering: A Discipline or a Specialty and Why It Matters.
- Author
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Grigg, Neil
- Subjects
WATER supply ,CIVIL engineers ,CIVIL engineering ,ENGINEERING ,EDITORIAL boards - Abstract
Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
5. Dilation Characteristics of FRP-Confined Square Engineered Cementitious Composite Columns.
- Author
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Li, Pengda, Huang, Deqing, Zhou, Yingwu, and Zheng, Songbin
- Subjects
COMPOSITE columns ,FIBER-reinforced plastics ,ULTIMATE strength ,CIVIL engineering ,ENGINEERING ,CIVIL engineers ,CEMENT composites - Abstract
As emerging high-performance concrete, the engineered cementitious composite (ECC) has demonstrated excellent application potential in civil engineering. With the wide application of ECC, it not only excels in the tension state and the structural elements but also in the more complex stress state of nonuniform confinement. For a reliable and economic ECC element design, understanding the dilation behavior of ECC is crucial under complicated stress conditions. This paper presents an experimental investigation and a detailed discussion of the ECC dilation characteristics under different confinement rigidities. The authors evaluate the effects of column parameters, such as different types of fiber-reinforced polymer (FRP) composites, confinement levels, and cross-sectional shapes. Test results indicate that the ECC dilation amplitude (secant dilation) under FRP confinement is less than that of concrete due to fiber bridge effects within ECC. However, the maximum dilation rate (tangent dilation ratio) shows an opposite trend. Based on the data analysis in this study, a new lateral strain-to-axial strain model was proposed, which can predict the dilation behavior of FRP-confined ECC with nonuniform confining pressure. The proposed model not only accurately captures the dilation process of FRP-confined ECC but also precisely predicts its ultimate strain. In addition, the existing peak strength and ultimate strength models were also evaluated by the ECC test results. The comparison indicates that the strength models for concrete also apply to FRP-confined ECC when the ultimate hoop-confining stress is accurately determined. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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6. Editor's Note.
- Author
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Longinow, Anatol
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CIVIL engineering ,STRUCTURAL design ,ARCHITECTURE ,CONSTRUCTION industry ,ENGINEERING - Abstract
Provides information on matters concerning civil engineering, structural design and construction.
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- 2004
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7. Potential Computational Benefits of Geometric, Kinematic, and Behavioral Downsampling of Microscopic Traffic Network Simulation.
- Author
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Ishak, Sherif, Alecsandru, Ciprian, and Chakravarthy, Srikanth
- Subjects
COMPUTER simulation ,ARTIFICIAL neural networks ,TRAFFIC patterns ,CIVIL engineering ,ENGINEERING - Abstract
This paper introduces the concept of microscopic simulation system scalability for the purpose of reducing the computational requirements of microsimulation modeling of large-scale traffic networks. This exploratory stage of research investigates scalability of both lane-changing and car-following behavior. The main objective of the proposed methodology is to create a reduced-scale network (microcosm) that retains most of the significant characteristics of the full-scale network (prototype). To achieve this objective a systematic downsampling procedure has been applied to a case study of a one-lane homogeneous freeway corridor in order to create a geometrically, kinematically, and behaviorally equivalent microcosm environment. This paper examines the scalability of lane-changing behavior, assuming a shifted negative exponential headway distribution, and investigates the scalability of car-following behavior under various operating conditions and downsampling ratios. The paper focuses on the tradeoff between performance and scalability of microscopic simulation systems. For each of the 48 cases considered, optimal behavioral parameters were determined based on two optimization methods: (1) Microscopic based on minimization of trajectory errors in both environments and (2) macroscopic derived from minimization of density errors in both environments throughout the simulation period. The results show that both optimization solutions were consistent in determining the optimal behavioral parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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8. Bioinspired Computational Framework for Enhancing Creativity, Optimality, and Robustness in Design.
- Author
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Kicinger, Rafal and Arciszewski, Tomasz
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COMPUTER simulation ,COMPUTER-aided design ,STRUCTURAL design ,ENGINEERING design ,CIVIL engineering ,ENGINEERING - Abstract
This paper presents results of transdisciplinary research on the development of a bioinspired computational framework for engineering design. This framework is intended to support design by addressing three critical design objectives, including novelty, optimality, and robustness. It provides several computational models and methods, which are inspired by fundamental processes occurring in nature, and discusses their potential for enhancing design. They include models and methods for evolutionary, developmental, and coevolutionary design. Their use is illustrated with examples from the area of steel structural design ranging from a simple cantilever beam design problem to a much more complex problem of designing wind bracings in tall buildings. The paper also shows how several methods and models can be integrated and form a coherent bioinspired computational framework for engineering design. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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9. Methodology for Usability Evaluation of Corporate Memory Design Reuse Systems.
- Author
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Demian, Peter and Fruchter, Renate
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ENGINEERING design ,AUTOMATION ,COMPUTER systems ,CIVIL engineering ,ENGINEERING - Abstract
Improving and supporting the process of design knowledge reuse in engineering design can increase productivity, improve the quality of designs, and lead to greater corporate competitive advantage. Whereas internal knowledge reuse from one’s personal experiences is very effective, external knowledge reuse from an external digital or paper archive often fails. Based on a formalization of the internal reuse process from ethnographic studies, a prototype system, CoMem (corporate memory) is presented, which supports the reuse process, particularly the steps of finding and understanding. This paper presents a usability testing framework and methodology for the evaluation of reuse systems such as CoMem. The two pertinent variables are (1) the type of finding task; and (2) the size of the repository. Preliminary results from the evaluation of CoMem are presented as an example of the application of this framework for studying and assessing corporate memory design reuse systems. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
10. Optimal H∞ Output Feedback Control Systems with Time Delay.
- Author
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Chi-Chang Lin, Chang-Ching Chang, and Huang-Lin Chen
- Subjects
ENTROPY ,EARTHQUAKE engineering ,FEEDBACK control systems ,TIME delay systems ,ENGINEERING geology ,CIVIL engineering ,ENGINEERING - Abstract
An H
∞ direct output feedback control algorithm through minimizing the entropy, a performance index measuring the tradeoff between H∞ optimality and H2 optimality, is developed in this paper to reduce the earthquake response of structures. To achieve optimal control performance and assure control system stability, the strategy to select both control parameters γ and α is extensively investigated considering the control force execution time delay. It is found that a lower bound of γ and an upper bound of α exist. The selection beyond these values will cause the control system instability. For a damped structure, analytical expressions of direct output feedback gains, controlled frequencies and damping ratios are derived. It can be proved that the conventional LQR control is a special case of the developed H∞ control. In real active control, control force execution time delay cannot be avoided. This paper gives explicit formulas of maximum allowable delay time and critical control parameters for the design of a stable control system. Some solutions are also proposed to lengthen maximum allowable delay times. [ABSTRACT FROM AUTHOR]- Published
- 2006
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- View/download PDF
11. Engineering Experience and Competitions Implement ABET Criteria.
- Author
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Koehn, Enno "Ed"
- Subjects
CIVIL engineering ,ENGINEERING ,INDUSTRIAL arts ,OPERATIONS research ,STRUCTURAL engineering ,ENGINEERING students - Abstract
The Accreditation Board for Engineering and Technology (ABET) has adopted a revised set of criteria for accrediting engineering programs. Nevertheless, as in the past, civil engineering departments will be required to demonstrate proficiency in specific subject areas which are included in the ABET program criteria. This paper investigates, according to civil engineering students, the level at which their understanding of various subjects required by ABET and listed in the Program Criteria for Civil and Similarly Named Engineering Programs and the General Criteria (Professional Component) has been enhanced by being involved with projects associated with the steel bridge and concrete canoe competitions. The results are also compared with students who have practical civil engineering experience. In particular, the findings suggest that students who are directly involved with project work believe that four areas have been greatly enhanced. They include: structural engineering, project management/scheduling and estimating, constructability, and teamwork. Understanding of engineering codes and standards, health and safety issues, materials engineering, and ethical considerations are also perceived to be enhanced. Furthermore, the results complement documentation from the American Institute of Steel Construction including comments from students participating in the steel bridge competition. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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- View/download PDF
12. Developing Knowledge Landscapes through Project-Based Learning.
- Author
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Chinowsky, Paul S., Brown, Hyman, Szajnman, Alberto, and Realph, Allison
- Subjects
CIVIL engineering ,ENGINEERING ,PRODUCTION scheduling ,MANAGEMENT ,CONSTRUCTION industry - Abstract
The traditional civil engineering-based approach to construction engineering and management education focuses significant attention on core subjects such as scheduling, estimating, and contracts. This paper introduces an alternative approach to this education based on the concepts of project-based learning. Through the introduction of courses developed by the writers, the paper provides a foundation for changing current education approaches from a lecture-based format to a project-based format. In this format, students are challenged with open-ended problems requiring greater application of multiple engineering concepts as well as requiring interaction with outside experts from within the construction industry and related professions. An outline for a project-based learning course is presented with experiences and lessons learned from four implementations of the course. Student responses are presented to indicate the potential benefits of such an approach. This finding is further supported by the introduction of the Knowledge Landscape concept for construction education that emphasizes greater use of context, scope, and multiple intelligences in construction engineering education. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
13. Soils Magic: Bringing Civil Engineering to the K–12 Classroom.
- Author
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Elton, David J., Hanson, James L., and Shannon, David M.
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CIVIL engineering ,ENGINEERING ,INDUSTRIAL arts ,TECHNOLOGY ,COLLEGE teachers - Abstract
An investigation was conducted to assess the effectiveness of a series of kindergarten through 12th grade (K–12) educational outreach activities related to civil engineering. In particular, a program called Soils Magic that contains a series of simple geotechnical engineering experiments was delivered in various formats to K–12 students. This paper provides an overview of the Soils Magic program and provides further details of selected experiments from the program. This paper highlights the experiences of various civil engineering professors bringing the program to school children to promote the excitement and accessibility of the engineering profession. Suggestions are provided for conducting successful educational outreach programs. The effectiveness of the program was evaluated using survey responses of the program participants. The need for outreach activities that promote science and engineering in an entertaining manner was established using survey responses of K–12 students. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
14. Computing Pit Excavation Volume.
- Author
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Yanalak, M.
- Subjects
EXCAVATION ,CIVIL engineering ,GEOGRIDS ,SURVEYS ,ENGINEERING - Abstract
The estimation of borrow pit volumes is common in many surveying and highway applications. The trapezoidal method (rectangular or triangular prisms), classical cross sectioning (trapezoidal, Simpson, and average formula), and improved methods (Simpson-based, cubic spline, and cubic Hermite formula) have been presented in the literature. The purpose of this paper is to compare volumes determined by the existing methods with volumes calculated by rectangular prisms using the gridding method of natural neighbor on example 2 in a paper by Chen and Lin, which was also used in a work by Easa. The multiquadric and minimum curvature gridding methods tested in Yanalak and Baykal are also applied to this example. For these volumes, excavation height values in a 1 m grid are interpolated using gridding methods of natural neighbor, multiquadric, and minimum curvature. Then, excavation volume is determined as rectangular prisms. The results are compared with the existing volumes in a paper by Easa. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
15. Assessment of the Computing Component of Civil Engineering Education.
- Author
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Abudayyeh, Osama, Cai, Hubo, Fenves, Steven J., Law, Kincho, O'Neill, Robert, and Rasdorf, William
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CIVIL engineering ,INFORMATION technology ,COMPUTER software ,COMPUTER systems ,ENGINEERING - Abstract
This paper presents the results of two surveys conducted by the American Society of Civil Engineers’ Task Committee on Computing Education of the Technical Council on Computing and Information Technology to assess the current computing component of the curriculum in civil engineering. Previous surveys completed in 1989 and 1995 have addressed the question of what should be taught to civil engineering students regarding computing. The surveys reported in this paper are a follow-up study to the two earlier surveys. Key findings of the study include: (1) the relative importance of the top four skills (spreadsheets, word processors, computer aided-design, electronic communication) has remained unchanged; (2) programming competence is ranked very low by practitioners; (3) the importance and use of geographic information system and specialized engineering software have increased over the past decade; (4) the importance and use of expert systems have significantly decreased over the past decade; and (5) the importance and use of equation solvers and databases have declined over the past decade. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
16. Enhancing Civil Engineering Education and ABET Criteria through Practical Experience.
- Author
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Koehn, Enno
- Subjects
ENGINEERING ,EDUCATIONAL accreditation ,CIVIL engineering ,STRUCTURAL engineering ,PROJECT management - Abstract
The Accreditation Board for Engineering and Technology (ABET) has adopted a revised set of criteria for accrediting engineering programs. Nevertheless, as in the past, civil engineering departments will be required to demonstrate proficiency in specific subject areas which are included in the ABET program criteria. This paper investigates how civil engineering students at Lamar University improved their understanding of various subject areas required by ABET and listed in the Program Criteria for Civil and Similarly Named Engineering Programs and the General Criteria (professional component) by being involved with cooperative, part-time, and summer work experiences. In particular, the findings suggest that both undergraduate and graduate students believe that three areas have been greatly enhanced with engineering work. They include structural engineering, project management/scheduling and estimating, and teamwork. In addition, undergraduates perceive that their understanding of health and safety issues and ethical considerations has also increased. In contrast, graduate students believe that their knowledge of hydraulics, hydrology, and water resources, constructability, and economic factors has been enhanced by civil engineering work experiences. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
17. Combining Service Learning with Graduate Education.
- Author
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Talbert, Matthew, Farnkhopf, Stephanie, Jones, Sharon A., and Houghtalen, Robert
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ENVIRONMENTAL engineering ,CIVIL engineering ,ENGINEERING ,LEARNING ,GRADUATE education ,CURRICULUM - Abstract
The Department of Civil Engineering at Rose-Hulman Institute of Technology recently modified its Master of Science program in environmental engineering. The thesis requirement has been replaced with a structured design course with real-world projects that are primarily for nonprofit organizations. The design course was modeled after the undergraduate senior design course within the department. In addition to a quality design experience, students now perform a service for the community. This paper emphasizes the service-learning aspects of the course using a case study of a completed project. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
18. Use of a Single L1 GPS Receiver for Monitoring Structures: First Results of the Detection of Millimetric Dynamic Oscillations.
- Author
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Schaal, Ricardo E., Larocca, Ana Paula C., and Guimarães, Gabriel N.
- Subjects
GLOBAL Positioning System ,FREQUENCIES of oscillating systems ,SURVEYING (Engineering) ,CIVIL engineering ,ENGINEERING - Abstract
This paper presents preliminary results to determine small displacements of a global positioning system (GPS) antenna fastened to a structure using only one L1 GPS receiver. Vibrations, periodic or not, are common in large structures, such as bridges, footbridges, tall buildings, and towers under dynamic loads. The behavior in time and frequency leads to structural analysis studies. The hypothesis of this article is that any large structure that presents vibrations in the centimeter-to-millimeter range can be monitored by phase measurements of a single L1 receiver with a high data rate, as long as the direction of the displacement is pointing to a particular satellite. Within this scenario, the carrier phase will be modulated by antenna displacement. During a period of a few dozen seconds, the relative displacement to the satellite, the satellite clock, and the atmospheric phase delays can be assumed as a polynomial time function. The residuals from a polynomial adjustment contain the phase modulation owing to small displacements, random noise, receiver clock short time instabilities, and multipath. The results showed that it is possible to detect displacements of centimeters in the phase data of a single satellite and millimeters in the difference between the phases of two satellites. After applying a periodic nonsinusoidal displacement of 10 m to the antenna, it is clearly recovered in the difference of the residuals. The time domain spectrum obtained by the fast Fourier transform (FFT) exhibited a defined peak of the third harmonic much more than the random noise using the proposed third-degree polynomial model. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
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19. Mitigating Epistemic Uncertainty in Structural Identification: Case Study for a Long-Span Steel Arch Bridge.
- Author
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Pan, Qin, Grimmelsman, Kirk, Moon, Franklin, and Aktan, Emin
- Subjects
BRIDGES ,CIVIL engineering ,INFRASTRUCTURE (Economics) ,ENGINEERING ,ARCH bridges ,FINITE element method - Abstract
Characterization of constructed civil-engineering systems through structural identification (St-Id) has gained increasing attention in recent years due to its potential to enable more effective infrastructure asset management and performance-based engineering. Although there have been recent advances that mitigate the challenges posed by aleatory (random) uncertainty, there are many remaining challenges associated with epistemic (bias) uncertainty that often have a more critical impact on the reliability of St-Id (especially with applications to constructed systems). The objective of this paper is to illustrate various sources of epistemic uncertainty and describe mitigation approaches by detailing the St-Id of a long-span steel arch bridge. This application includes a priori modeling, ambient vibration monitoring, data processing, feature extraction, and finite-element (FE) model correlation. Following a description of the St-Id, the impact of various modeling uncertainties on the calibrated FE model is evaluated by comparing different identification scenarios. Finally, a simple and rational approach to 'truth testing' the identified model is developed and employed to determine its admissibility. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
20. Methodology to Assess Building Designs for Protection against Internal Chemical and Biological Threats.
- Author
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Nakano, Victor M., Croisant, William J., and Abraham, Dulcy M.
- Subjects
METHODOLOGY ,ARCHITECTURE ,TERRORISM ,CIVIL engineering ,EXPERIMENTAL design ,ENGINEERING - Abstract
Recent world events involving chemical and biological (CB) attacks within critical infrastructure have highlighted a potential threat to buildings and their occupants. As a result, protecting buildings from CB attacks has become an important design consideration. A methodology has been developed to provide decision makers with the ability to assess multiple building designs for protection against an internal CB release. This methodology includes modeling and simulation of CB contaminant dispersion, a quantitative means to calculate a building’s protection level, and a weighted sum, multiple objective optimization for design selection. This paper outlines the phases in the methodology, and focuses on the application of multizone modeling and optimization techniques to compare design alternatives. The assessment of design options for CB protection in a hospital emergency room is used as an illustrative example. Optimal design options are determined based on the weighted combination functions for the building’s protection level, initial capital costs, and ongoing operations and maintenance costs. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
21. Methodology for Automating the Identification and Localization of Construction Components on Industrial Projects.
- Author
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Torrent, David Grau and Caldas, Carlos H.
- Subjects
AUTOMATION ,CIVIL engineering ,CONSTRUCTION materials ,ALGORITHMS ,CONSTRUCTION projects ,ENGINEERING - Abstract
Even though engineered components, such as pipe spools and structural steel elements, generally account for a significant percentage of the total installed cost of an industrial project, current industry practices still rely on human ability to track thousands of these components individually after they are received at the job site. These site-tracking practices are inefficient and error prone. This paper presents an approach for automating the identification and localization of construction components on large industrial projects. The proposed approach combines advanced sensing devices and localization mechanisms. The appropriate combination of global positioning system and radio-frequency identification (RFID) facilitates an infrastructure-free data collection process capable of detecting a large number of RFID-tagged components in short amounts of time. Based on the collected data, localization mechanisms precisely estimate the coordinates of the tagged components. Field experiments on real construction scenarios demonstrated the feasibility of the proposed methodology. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
22. Probabilistic Approach to the Solution of Inverse Problems in Civil Engineering.
- Author
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Hadidi, Rambod and Gucunski, Nenad
- Subjects
CIVIL engineering ,HEISENBERG uncertainty principle ,NUMERICAL analysis ,MONTE Carlo method ,PROBABILITY theory ,INVERSE problems - Abstract
A wide range of important problems in civil engineering can be classified as inverse problems. In such problems, the observational data regarding the performance of a system is known, and the characteristics of the system and/or the input are sought. There are two general approaches to the solution of inverse problems: deterministic and probabilistic. Traditionally, inverse problems in civil engineering have been solved using a deterministic approach. In this approach, the objective is to find a specific model of a system that its theoretical response best fits the observed data. Obtaining the best fit solution, however, does not provide any information regarding the effect of data and/or theoretical uncertainties on the obtained solution. In this paper, a general probabilistic approach to the solution of the inverse problems is introduced, which provides uncertainty measures for the obtained solution. Techniques for direct analytical evaluation and numerical approximation of the probabilistic solution using Monte Carlo Markov Chains, with and without neighborhood algorithm approximation, are introduced and explained. The presented concepts and techniques and their application are then illustrated in practical terms using a simple example of a modulus determination experiment. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
23. Reliability Index for Serviceability Limit State of Building Foundations.
- Author
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Wang, Yu and Kulhawy, Fred H.
- Subjects
CIVIL engineering ,PILES & pile driving ,ENGINEERING ,IRON & steel plates ,MONTE Carlo method - Abstract
Extensive research has been conducted on reliability-based design (RBD) for the ultimate limit state (ULS). Several RBD codes have been developed and implemented around the world that calibrate the ULS design for a target ULS reliability index (β
uls ). However, the serviceability limit-state (SLS) design still is considered using conventional deterministic approaches with an unknown SLS reliability index (βsls ). This paper presents a relationship between βsls and the βuls that is specified already in the RBD codes. This relationship is linear, and a key variable in it is the ratio (R) of the SLS capacity (Qsls ) to the ULS capacity (Quls ). Both closed-form approximations and Monte Carlo simulations are used to characterize R probabilistically. For illustration, the relationship then is used to estimate βsls for augered cast-in-place piles designed in accordance with the RBD methodologies in the National Building Code of Canada. The results are highly dependent on the statistics of the limiting tolerable foundation settlement (ylt ). For larger ylt values, the calculated βsls >βuls , which means that ULS designs automatically satisfy SLS criteria. For smaller ylt values, SLS criteria begin to control the design. The importance of sound ylt criteria is stressed. [ABSTRACT FROM AUTHOR]- Published
- 2008
- Full Text
- View/download PDF
24. Field Evaluation of Roundabout Turning Movement Estimation Procedures.
- Author
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Dixon, Michael P., Abdel-Rahim, Ahmed, Kyte, Michael, Rust, Phil, Cooley, Howard, and Rodegerdts, Lee
- Subjects
STATISTICAL sampling ,STATISTICS ,TRANSPORTATION engineering ,CIVIL engineering ,ENGINEERING - Abstract
Tracking vehicles through roundabouts is laborious. Because of this, turning movement volumes are usually estimated using a variety of methods. This paper identifies and evaluates practical methods of estimating turning movement volumes at roundabouts. Thirty four experiments were used to test the effects of different estimation treatments: estimation procedure, time interval size, count location configuration, and turning movement sample procedure. A new economical sampling procedure was introduced and included in the experiment design. The experiments were evaluated using volume estimation and capacity estimation errors. Findings showed that the new sample procedure works well relative to a random sampling procedure. Other insights were gained regarding the four treatments included in the experiment design. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
25. Cellular Automata Model for Predicting the Failure Pattern of Laterally Loaded Masonry Wall Panels.
- Author
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Zhou, G. C., Rafiq, M. Y., Bugmann, G., and Easterbrook, D. J.
- Subjects
BUILDING failures ,WALLS ,MASONRY ,CIVIL engineering ,ENGINEERING - Abstract
This paper introduces a technique that directly predicts the failure patterns of laterally loaded masonry panels based on the results of existing typical panels tested in the laboratory. The technique is based on the use of the cellular automata (CA). In this technique, the CA modeling is established to propagate boundary effects to zones within a panel. The corresponding rules for the state values of zones are derived from the proposed CA model, using appropriate transition functions. These state values are then used by the CA to establish zone similarity between two panels. Finally, the zone similarity is applied to establish locations of cracks on the panel. The technique is used in a novel way that eliminates the use of any numerical tools such as finite-element analysis (FEA). This technique is purely based on comparing the failure pattern of the base panel (a panel whose failure pattern is known from the laboratory tests) and unseen panels (panels not tested in the laboratory by the writers or with unknown failure patterns) subjected to the same type of loading and with similar boundary conditions to predict the failure load of the unseen panels. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
26. Effects of Local Search Algorithms on Groundwater Remediation Optimization Using a Self-Adaptive Hybrid Genetic Algorithm.
- Author
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Espinoza, Felipe P. and Minsker, Barbara S.
- Subjects
GENETIC algorithms ,MATHEMATICAL optimization ,GROUNDWATER remediation ,CIVIL engineering ,ENGINEERING - Abstract
Genetic algorithms allow solution of more complex, nonlinear civil, and environmental engineering problems than traditional gradient-based approaches, but they are more computationally intensive. One way to improve algorithm performance is through inclusion of local search, creating a hybrid genetic algorithm (HGA). The inclusion of local search helps to speed up the solution process and to make the solution technique more robust. This paper focuses on the effects of different local search algorithms on the performance of two different HGAs developed in previous phases of this research, the self-adaptive hybrid genetic algorithm (SAHGA) and the enhanced SAHGA. The algorithms are tested on eight test functions from the genetic and evolutionary computation literature and a groundwater remediation design case study. The results show that the selection of the local search algorithm to be combined with the simple genetic algorithm is critical to algorithm performance. The best local search algorithm varies for different problems, but can be selected prior to solving the problem by examining the reduction in fitness standard deviation associated with each local search algorithm, and the time distribution associated to the local search algorithm. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
27. Neural Networks and Principal Component Analysis for Identification of Building Natural Periods.
- Author
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Kuźnia, Krystyna and Waszczyszyn, Zenon
- Subjects
ARTIFICIAL neural networks ,DATA compression ,ELECTRONIC data processing ,CIVIL engineering ,ENGINEERING ,BUILDINGS - Abstract
This paper deals with an application of neural networks for computation of fundamental natural periods of buildings with load-bearing walls. The analysis is based on long-term tests performed on actual structures. The identification problem is formulated as the relation between structural and soil basement parameters, and the fundamental period of building. The principal component analysis for compression of input data is also used. Backpropagation neural networks are applied in the analysis. Results of neural network identification of natural periods are compared with data from experiments. The application of the proposed neural networks enables us to identify the natural periods of the buildings with quite satisfactory accuracy for engineering practice. The compression of the input data to principal components by principal component analysis makes it possible to design much smaller neural networks than those without data compression with no greater increase of the neural approximation errors. It appears that this technique would also be very useful in damage detection and health monitoring of structures. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
28. Promising New Tool for Stakeholder Interaction.
- Author
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Orndoff, Cynthia J. Wilson
- Subjects
ENGINEERING ,RESEARCH ,METHODOLOGY ,INVESTORS ,INDUSTRIAL surveys ,CIVIL engineering - Abstract
This paper presents a research methodology combining the contingent value method (CVM) and the Delphi model, creating an interactive stakeholder interaction to enhance decision making and influence project performance and funding of civil engineering (CE) projects. While CE has historically focused only on physical infrastructure needs, the CVM–Delphi model allows for maximum stakeholder participation in determining asset value. Specifically, the research model discussed in this paper gathered information from three groups (decision makers, businesses, and the general public) through three rounds of survey instruments gaging asset valuation of a recent highway renovation in rural Illinois. The methodology provides a viable tool for decision makers in other engineering arenas to increase customer focus prior to enacting policies or projects. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
29. System Identification through Model Composition and Stochastic Search.
- Author
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Robert-Nicoud, Y., Raphael, B., and Smith, I. F. C.
- Subjects
SYSTEM identification ,DETECTORS ,STOCHASTIC processes ,CIVIL engineering ,ENGINEERING - Abstract
System identification methodologies are useful for identifying characteristics of structural systems using measurement data. However, incorrect systems might be identified when many combinations of system characteristics result in the same predicted responses at measured locations. The reliability of identification is affected by a number of factors that most previous work has overlooked. This paper presents a system identification methodology that explicitly treats factors that affect the success of identification. Rather than simply determining parametric values, this methodology also involves identification of model characteristics including boundary conditions. Due to inevitable modeling errors, models that provide absolute minimum differences between predictions and measurements are rarely correct models. In such situations, the challenge is to define a population of candidate models that result in such differences being below threshold values that are determined by the magnitude of modeling errors. The methodology is illustrated using a case study in civil engineering. This work contributes to providing engineers with general strategies to meet interpretation challenges associated with sensor data. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
30. Commodities and Value-Based Pricing of Engineering Services.
- Author
-
Farr, John V.
- Subjects
CIVIL engineering ,CIVIL engineers ,ENGINEERING - Abstract
This paper proposes that many civil engineering companies can be classified as either commodities or value-based providers of services. We examine the way civil engineers price and market services for these two types of products, explore when and how much should companies increase or decrease prices, and determine what are or may be the long-term ramifications on market share. Lastly, we propose a model for value-based pricing of civil engineering services. An understanding of the products they deliver, how to competitively price these products, and ideas for improving profitability should help civil engineering firms price and market their services to improve profitability and not lose market share. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
31. Performance Evaluation of a Stone Masonry-Arch Railway Bridge under Increased Axle Loads.
- Subjects
MASONRY ,CIVIL engineering ,ENGINEERING ,RAILROAD bridge design & construction ,ARCH bridge design & construction - Abstract
Many of the masonry arch bridges in the network of railway bridge stock belong to the civil engineering heritage of the railways. Therefore, their maintenance and management require careful consideration. An effective procedure for performance evaluation should promote solutions that are directed toward preservation and restoration of arch bridges by evaluating their existing structural capacity. In this paper, experimental methodologies adopted for the performance evaluation of a stone masonry-arch railway bridge are presented. One of the primary objectives of the current study was to evaluate the longitudinal force exerted on the bridge due to increased axle loads of freight wagons. An innovative technique using a flat jack was implemented for the evaluation of longitudinal stress due to increased axle load. Three-dimensional numerical modeling and analysis was carried out to identify the critical locations for fixing the flat jacks for evaluation of live-load stresses. A special instrumentation scheme with which very low strain can be measured was adopted for the evaluation of pier strains. From the field study, the maximum deflection under dynamic test conditions was found to be 0.465 mm and this is within the permissible limit. From the dynamic response measured using the flat jack, the maximum longitudinal stress in the arch due to tractive effort was approximately 0.3 MPa. It has been evaluated that the maximum longitudinal force (per rail) at rail level is 12.31T in the instrumented span. The responses measured from the bridge are within permissible limits. The methodology developed and implemented for the performance evaluation of arch bridges would pave the way for undertaking better and timely maintenance strategies. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
32. Numerical Investigation of the Scouring Effect on the Lateral Response of Piles in Sand.
- Author
-
Ni, Sheng-Huoo, Huang, Yan-Hong, and Lo, Kuo-Feng
- Subjects
CIVIL engineering ,ENGINEERING ,PUBLIC works ,STRAINS & stresses (Mechanics) ,STRUCTURAL analysis (Engineering) - Abstract
Scouring around a bridge foundation is a problem of much concern to civil engineers. The main purpose of this paper is to gain more understanding of the effect of scouring around the pile on the lateral capacity of the piles embedded in sandy soil. Factors such as soil stiffness, pile head fixity, and pile slenderness ratio (L/B) were studied to show their effects on the variation of the percentage decrease of lateral load capacity (PDC) due to scouring near an isolated pile. The results indicate that the PDC value reaches almost 50% when the scour depth reaches 1.3 to 2.4 times the pile diameter, and that piles with a fixed head are more capable of resisting lateral load loss. Furthermore, the PDC values remain almost constant after the pile slenderness ratio is greater than 10. Hence, the decrease in lateral load due to scouring of the soil will be more serious for short piles. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
33. Longitudinal Evaluation of a GIS Laboratory in a Transportation Engineering Course.
- Author
-
Bham, Ghulam H., Cernusca, Dan, Luna, Ronaldo, and Manepalli, Uday R. R.
- Subjects
INTERNET in education ,ENGINEERING ,ACTIVITY programs in education ,CIVIL engineering ,MOTOR vehicles - Abstract
This paper focuses on the potential impact of student-centered feedback for enhancing the learning experience of civil engineering students that used a geographic information system (GIS) based tutorial in a transportation engineering course. The tutorial was implemented in a laboratory environment developed as a self-guided activity supported by a web-based learning system. The formative research proposed in this study includes a series of four successive implementations of this laboratory. Students' performance, beliefs, and perceptions were monitored by using a mixed-methods design approach and weaknesses identified from early implementations were addressed before the next implementation of the laboratory activity. The students' performance was found to improve when the GIS web-based tutorial was complemented with an instructor-driven short introduction that anchored the laboratory activity in traffic safety. In addition, students' feedback in both quantitative and qualitative format indicated weaknesses related to the difficulty of the laboratory and usability factors such as speed and size of data uploading. As these weaknesses were addressed, students' positive input regarding the overall GIS laboratory experience significantly increased. This positive input was fully backed up by students' feedback indicating major strengths of the GIS laboratory for professional growth and future career development in civil and transportation engineering. Finally, students' inputs in the latest implementations provided valuable suggestions for future potential improvements regarding how to better integrate the GIS laboratory in course-related activities such as term projects. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
34. Digital Publishing, Indexing, and Ethics: Implications in Civil and Hydraulic Engineering and Research.
- Author
-
Chanson, Hubert
- Subjects
ELECTRONIC publishing ,ELECTRONIC information resources ,CIVIL engineering ,HYDRAULIC engineering ,ENGINEERING ,TECHNOLOGICAL innovations ,QUALITY - Abstract
The article focuses on the implications of digital publishing and related electronic information resources in civil and hydraulic engineering and research. It notes that the technological innovations have yielded abundant resource materials necessary for researches in civil and hydraulic engineering. However, it relates that the resource materials become useless unless critically evaluated by experts that could affect research quality and impact.
- Published
- 2009
- Full Text
- View/download PDF
35. Integrated Design of Controlled Linear Structural Systems.
- Author
-
Cimellaro, G. P., Soong, T. T., and Reinhorn, A. M.
- Subjects
STRUCTURAL analysis (Engineering) ,CIVIL engineering ,STRUCTURAL engineering ,STRUCTURAL frames ,CONSTRUCTION ,ENGINEERING - Abstract
This paper addresses the integrated design of civil engineering structures with control systems. Simultaneous optimization of such controlled structures is considered, showing that new alternative solutions can be achieved through integrated design. A procedure for design of controlled structural systems is developed using a two-stage approach: (1) a design of an optimal control system using a linear quadratic regulator algorithm; and (2) a redesign using an optimization procedure to match the performance of the controlled system obtained in (1). A linear single degree of freedom steel portal frame and a linear nine degree of freedom shear-type structure are used as examples to illustrate the feasibility of the proposed approach that reduces the structural weight of buildings by incorporating active or passive control elements while preserving the performance objectives. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
36. Implementing Metric Operators of a Spatial Query Language for 3D Building Models: Octree and B-Rep Approaches.
- Author
-
Borrmann, André, Schraufstetter, Stefanie, and Rank, Ernst
- Subjects
QUERY languages (Computer science) ,SPATIAL systems ,CONSTRUCTION ,ALGORITHMS ,CIVIL engineering ,ENGINEERING - Abstract
A spatial query language for building information models enables the spatial analysis of buildings and the extraction of partial models that fulfill certain spatial constraints. Among other features, the developed spatial query language includes metric operators, i.e., operators that reflect distance relationships between spatial objects, such as mindist, maxdist, isCloser and isFarther. The paper presents formal definitions of the semantics of these operators by using point set theory notation. It further describes two possible implementation methods: the first one is based on a discrete representation of the operands’ geometry by means of the hierarchical, space-partitioning data structure octree. The octree allows for the application of recursive algorithms that successively increase the discrete resolution of the spatial objects employed and thereby enables the user to trade off between computational effort and the required accuracy. By contrast, the second approach uses the exact boundary representation (B-Rep) of both spatial objects resulting in precise distance measurements. Here, the bounding facets of each operand are indexed by a so-called axis-aligned bounding boxes tree (AABB tree). The algorithm uses the AABB-tree structure to identify candidate pairs of facets, for which an exact but expensive distance algorithm is employed. The article compares both approaches by means of detailed investigations on the runtime performance of the developed algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
37. Experimental Investigation of Grouted Helical Piers for Use in Foundation Rehabilitation.
- Author
-
Yueying Bian, Hutchinson, Tara C., Wilson, Dan, Laefer, Debra, and Brandenberg, Scott
- Subjects
PIERS ,HYDRAULIC structures ,ENGINEERING geology ,SHAFTS (Excavations) ,EARTHWORK ,EXCAVATION ,GEOLOGY ,CIVIL engineering ,ENGINEERING - Abstract
Building rehabilitation is critical for numerous older urban areas, many of which have inadequate foundations to support new demands. Consequently, development of practical methods to strengthen existing foundations is crucial. In engineering practice, both subsurface grouting and helical piers have been widely used to address these issues by strengthening the foundation. If the solid shaft of a typical helical pier is replaced by a hollow shaft, then helical piers provide the ability to deliver grout. It is hypothesized that these grouted helical pier systems could address foundation strengthening needs. This paper presents findings from an exploratory research program where grouting and pier placement tools were developed and tested on the large geotechnical centrifuge at the University of California, Davis. Experimental methods and procedures developed are presented, and observations regarding the formation of grout bulbs under different conditions are analyzed. Physical observation of the test specimens indicates that average grout bulb diameters of 0.6–1.9 times the helix diameter (D
h ) are attainable. For similar grout mixes, 20–50% larger grout bulbs can be attained by adding just a modest amount of injection pressure. Future research may use these results to develop load performance data. [ABSTRACT FROM AUTHOR]- Published
- 2008
- Full Text
- View/download PDF
38. Correlation of Resilient and Seismic Modulus Test Results.
- Author
-
Williams, R. R. and Nazarian, S.
- Subjects
SEISMIC testing ,QUALITY control ,STRAINS & stresses (Mechanics) ,MATERIALS testing ,CIVIL engineering ,ENGINEERING - Abstract
The most common test to evaluate the representative modulus and nonlinear behavior of base and subgrade materials is the resilient modulus test. Due to the comprehensive nature of the method, the preparation and testing of one specimen may take up to 6 h. For field quality control, a more rapid method of determining the in-place modulus is desirable. One way to achieve this goal is through in situ seismic methods. However, since the seismic tests provide small-strain moduli whereas the resilient modulus tests measure moduli at higher strains, some additional considerations must be taken into account to relate these two moduli. This paper presents some possibilities for relating these tests in a rational manner. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
39. Restructuring the Undergraduate Laboratory Instructional Process.
- Author
-
Truax, Dennis D.
- Subjects
CIVIL engineering ,ENGINEERING ,CIVIL engineering education ,TRAINING - Abstract
There is little doubt that a laboratory experience can be a beneficial component of the undergraduate engineering learning process. Observing physical demonstrations of textbook and lecture information can enhance a student’s perception of a concept and produce clarity of key issues. Unfortunately, limitations often exist that constrain the developing laboratories and sometimes reducing the student’s experience to little more than performing “cookbook” experiments and copying previous lab reports; an exercise that benefits neither the instructor nor the student. This paper summarizes an alternative approach for undergraduate laboratory instruction that relies on the undergraduate students working in teams to design and conduct experiments. The instructor acts as mentor to a process that ensures a quality laboratory exercise without being the sole responsible party. The students’ learning is increased and the laboratory experience is enhanced due, in part, to the experiments being designed by students and for students; matching students’ needs, education, and interests with experiments. An additional benefit comes from participants being immersed into the concepts of experimental design and analysis using a team of peers. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
40. Linear Predictor-Based Lossless Compression of Vibration Sensor Data: Systems Approach.
- Author
-
Zhang, Yunfeng and Li, Jian
- Subjects
ENGINEERING ,ELECTRONIC data processing ,INFORMATION resources management ,SIGNAL processing ,VIBRATION (Mechanics) ,DATA compression ,DETECTORS ,CIVIL engineering - Abstract
This paper presents a novel systems approach to compressing sensor network data. Unlike previous data compression methods, the proposed lossless linear predictor-based sensor data compression method utilizes structural system information to minimize the signal correlation in sensor network data. In the proposed method, linear predictor is derived in a system identification framework in which auto-regressive (AR) model is used as its model structure and the instrumental variables (IV) method is used to calculate the predictor parameters. A parametric study was carried out to study the effects of changes in system property, number of sensors, and sensor noise level on the compression performance of the proposed method. Both numerical simulation and experimental results show that the proposed sensor data compression method has a better compression performance than conventional linear predictor-based data compression method for single sensor. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
41. Passing Opportunities at Slow-Vehicle Bays.
- Author
-
Koorey, Glen
- Subjects
ROADS ,TRANSPORTATION engineering ,CIVIL engineering ,ENGINEERING - Abstract
Recently ways of assessing the need for and providing for improved passing opportunities on rural two-lane (single-carriageway) highways has been investigated in New Zealand. This paper focuses on studies of the performance of slow-vehicle bays (SVBs), also known as “turnouts.” Field surveys at eight sites identified the effect of different features on SVB usage and on reduction in following. Higher levels of SVB use than reported overseas were observed; however, this use appears to be very dependent on the location and design of each site. The SVBs’ effects on vehicle following was generally not substantial, although the short-term benefits probably reduce driver frustration. Minimum desirable lengths for SVBs were also reviewed, and it was found that the current New Zealand guidelines for SVB lengths may be inappropriate, given the number of merged area conflicts and multivehicle queues SVBs create on the roads. From these findings, project evaluation methods were developed using simplified analytical procedures and a simulation modeling package. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
42. Wavelet-Based Vibration Sensor Data Compression Technique for Civil Infrastructure Condition Monitoring.
- Author
-
Yunfeng Zhang and Jian Li
- Subjects
DATA compression ,INFRASTRUCTURE (Economics) ,BUILDINGS ,CIVIL engineering ,ENGINEERING - Abstract
Civil infrastructure condition monitoring generates large volumes of sensor data. Huge data size impedes fast and reliable distribution of sensor data, especially for wireless sensor networks. Vibration sensor data plays an important role in many useful structural health monitoring methods. This paper presents a vibration sensor data compression technique based on the lifting scheme wavelet transform (LSWT). Real sensor data from a nine-story building as well as a steel truss bridge was used to examine the compression performance of the LSWT-based vibration sensor data compression technique. It is found that the LSWT-based vibration sensor data compression technique can achieve a very high compression ratio while retaining the basic waveform properties of original sensor data. Additionally, LSWT has a feature that supports progressive compression and thus allows for multiresolution data transmission and retrieval. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
43. Research Publication Trends and Topics in Computing in Civil Engineering.
- Author
-
Abudayyeh, Osama, Dibert-DeYoung, Amber, Rasdorf, William, and Melhem, Hani
- Subjects
- *
CIVIL engineering , *AUTOMATION , *RESEARCH , *PUBLICATIONS , *ENGINEERING - Abstract
This paper provides a historical perspective on computing research in civil engineering, as reflected in the Journal of Computing in Civil Engineering (JCCE). The paper reports the results of a 17 year analysis of the Journal from 1987 through 2003. The main computing topical content as well as the origin and distribution of research sources and dissemination venues are summarized. The JCCE is intended to be of interest to researchers, professionals, and students in all civil engineering disciplines. This paper is intended to shed light on its content. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
44. Reviewers.
- Subjects
PERIODICALS ,TRANSPORTATION engineering ,TRANSPORTATION ,CIVIL engineering ,ENGINEERING - Abstract
Presents a list of people who have reviewed papers submitted to the "Journal of Transportation Engineering," during the period of July 1, 2004 to June 2005.
- Published
- 2005
- Full Text
- View/download PDF
45. Integrated Device Placement and Control Design in Civil Structures Using Genetic Algorithms.
- Author
-
Ping Tan, Dyke, Shirley J., Richardson, Andy, and Abdullah, Makola
- Subjects
BUILDINGS ,CONTACTOR control systems ,GENETIC algorithms ,ALGORITHMS ,COMBINATORIAL optimization ,CIVIL engineering ,ENGINEERING - Abstract
One challenge in the application of control systems to civil engineering structures is appropriate integration of a control system into a structure to achieve effective performance. Placement of control devices is strongly linked to the performance of a control system, and the most appropriate device placement scheme is strongly dependent on the performance objectives of the control system. Additionally, for the most effective control system, the placement scheme should be integrated with the design of the controller rather than sequential. This paper proposes an integrated technique to place devices and design controllers based on the use of genetic algorithms. The approach is flexible, allowing the designer to base the placement scheme on performance goals and/or system requirements. Active control devices are used and an H
2 /LQG controller based on acceleration feedback is selected for this study based on previous successes with this approach in civil engineering systems. To illustrate the proposed methodology, two numerical examples are considered. The first example considers a 40-story shear building, and the second is a full-scale, irregular, nine-story building. Control is achieved through the placement of one or more active control devices placed on various floors in an active bracing configuration. The improvements in the effectiveness of the proposed methodology as compared to previously developed techniques are demonstrated through comparative studies. [ABSTRACT FROM AUTHOR]- Published
- 2005
- Full Text
- View/download PDF
46. Theoretical Modeling of Signal Loss versus Crack Opening for a Novel Crack Sensor.
- Author
-
Leung, Christopher K. Y., Olson, Noah, Kai Tai Wan, and Meng, Aidong
- Subjects
DETECTORS ,ENGINEERING instruments ,CIVIL engineering ,ENGINEERING - Abstract
The degradation of concrete structures is always accompanied by the formation of cracks. Crack monitoring is hence useful in assessing the “health condition” of the structure. In our previous investigation on an optical-fiber crack sensor, we have successfully demonstrated the possibility of crack detection and monitoring without requiring prior knowledge of crack locations. Also, a single fiber can be employed to monitor a number of cracks. In practical applications, the signal loss versus crack opening relationship of the sensor needs to be properly “designed” to satisfy performance requirements on sensitivity to small cracks and/or the total number of detectable cracks (which is limited by the maximum loss at each crack). In this paper, a theoretical model for the signal loss versus crack opening relationship is developed through a combination of mechanical and optical analyses. Using concrete beams with embedded sensors, crack monitoring experiments are conducted. Test results are found to be in reasonably good agreement with predictions from the model. With the verified model, simulations are carried out to study the effect of various parameters on sensor performance. The potential application of the theoretical model to generate sensor design guidelines is hence demonstrated. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
47. Nonlinear Interaction of Soil–Pile in Horizontal Vibration.
- Author
-
Chau, K. T. and Yang, X.
- Subjects
VIBRATION (Mechanics) ,ENGINEERING design ,CIVIL engineering ,ENGINEERING - Abstract
This paper presents a new model for analyzing a nonlinear soil–pile interaction subject to horizontal shaking of a vertical circular pile embedded in a soil layer of finite thickness. The pile rests on bedrock with either a pinned or a clamped support. The soil mass is assumed composing of a “semi-nonlinear” inner soil zone around the pile and a linear viscoelastic soil zone outside the inner zone. When the inner soil behaves linearly, the present solutions are identical to those obtained by Nogami and Novak in 1977. Numerical results show that soil resistance of less slender piles developed against the vibration is larger than that of more slender piles. Soil resistance depends more strongly on the size of the nonlinear inner zone when the pile is vibrating at a frequency higher than the natural frequency of the soil. Soil nonlinearity, in general, results in a smaller damping and stiffness of the soil–pile system, except at high frequency. At higher vibration frequency, the situation can be very complicated. The exact value of the dynamic stiffness of the soil–pile system depends on elastic shear wave speed, soil nonlinearity, vibration frequency, slenderness ratio of the pile, magnitude of vibration, and tip conditions of the pile. Generally speaking, the dynamic stiffness is smaller than the static stiffness. The normalized dynamic stiffness for pile with a pinned tip is, in general, larger than that with a clamped tip, while the reverse is true for the damping. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
48. Multiple-Criteria Evaluation for Value Management in Civil Engineering.
- Author
-
Sánchez, Mónica, Prats, Francesc, Agell, Núria, and Ormazabal, Gaizka
- Subjects
EVALUATION ,MANAGEMENT ,CIVIL engineering ,ENGINEERING ,INDUSTRIAL arts - Abstract
This paper presents a fuzzy set-based approach for representing and synthesizing information about the different kinds of variables involved in the evaluation of a project’s value. The variables considered can be quantitative crisp or fuzzy as well as qualitative ordinal. The information is given either by a single expert or by a team of experts. The proposed methodology for summarizing and normalizing values aims at contributing to decision-making analysis in the context of multiple-criteria evaluation and group decision making. The conditions that the aggregation function to be used must satisfy are also discussed. The weighted sum is characterized under quite restrictive assumptions, presenting a theorem based on Cauchy’s functional equation. The aggregation function proposed is the weighted sum, with weights computed by a well-known analytic hierarchy process. A design is given of a fuzzy system for evaluating a project’s value in the context of construction in civil engineering. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
49. Geology: Engineer Ignore It at Your Peril.
- Author
-
Rollings, Marian P. and Rollings, Raymond S.
- Subjects
CIVIL engineering ,GEOLOGY ,ENGINEERING ,CONSTRUCTION contracts ,ENGINEERING design ,TECHNOLOGY - Abstract
Geology and related earth processes are an inherent part of civil engineering design and construction. This paper examines eight specific examples to illustrate how geologic factors can dominate project behavior. The examples are from a spectrum of environments associated with design and construction of roads and airfields and vary from the apparently obvious to the more subtle. Failure to understand the geologic conditions at a site almost invariably results in unsatisfactory performance. This complex interplay between geology and engineering is at the heart of the geotechnical profession and should be appreciated by all. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
50. Evaluation of an Emerging Market in Subsurface Utility Engineering.
- Author
-
Jeong, Hyung Seok, Abraham, Dulcy M., and Lew, Jeffrey J.
- Subjects
UNDERGROUND construction ,CIVIL engineering ,CONSTRUCTION industry ,ENGINEERING - Abstract
Subsurface utility engineering (SUE) is a fast growing industry segment in the civil engineering arena. Subsurface utility engineering is gaining credibility as a significant tool to reduce the risk from informational uncertainty associated with underground facilities in a construction project. Subsurface utility engineering can minimize the risk primarily through mapping existing underground utility facilities, utilizing surface geophysical technologies, surveying and data management systems. This paper presents a comprehensive evaluation of SUE to facilitate a better understanding of this emerging industry by the many in the construction domain that are relatively unfamiliar with it. Topics investigated include quality levels in SUE, incorporation of SUE strategy at different stages in the construction project, and cost–benefit analysis of SUE based on 71 actual construction projects where SUE was employed. In addition, the results obtained from questionnaire surveys of State Departments of Transportation (DOTs) and the SUE industry are analyzed, which reveal the trend of state DOTs in the use of SUE and various aspects of SUE business in private sectors. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
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