Earthbound Civil Engineering Experience for Space Applications

Since the dawn of civilization, the civil engineering profession has served mankind. Civil engineers have provided humanity with safe, reliable, and economical facilities and a livable environment. This paper seeks to outline the potential applications of various Earth‐based civil engineering fields for the engineering, construction, and operation of facilities in space stations in Earth orbit, bases on the Moon and Mars, and the exploration of other extraterrestrial bodies. On Earth, civil engineers have played a key role in design, construction, and operation of ground‐support facilities since the beginning of the space program. The vast and diverse Earth‐based knowledge and experience earned by civil engineers could be applied to create a suitable infrastructure in space to satisfy human needs. Therefore, civil engineers can play a significant role in the future expansion of human endeavors into space. The time has come for civil engineers throughout the world to come together; take the challenge posed by time, human needs, and ambition; and extend their joint expertise toward large‐scale projects in space for the benefit of all.     

Planning for Civil Engineering Applications of Information Technology

Providers of civil engineering infrastructure face increasing pressure to apply information technology. Unfortunately, technology's rapid evolution renders it easy to acquire expensive equipment that quickly becomes obsolete. In response, this paper outlines a systems analysis planning approach that focuses on the long-term goals of engineering managers. Using the case study method, the strengths and weaknesses of a relatively new technology, the World Wide Web, are mapped to the goals of a key civil infrastructure user, a transit provider. Six strategic areas are identified where the Web can have a high impact on the delivery of transit services: attracting greater advertising revenue, improving the image of the service, improving services for existing patrons, attracting other market segments, educating customers, and facilitating electronic commerce. The value of this goal-oriented planning application is that uncommon but practical transit initiatives are identified, several of which would have been undiscovered had a more traditional technology-oriented approach been employed. The significance of this approach is that one makes better investments rather than simply better justifications for existing projects.     

Applications and Issues of GIS as Tool for Civil Engineering Modeling

A tool that has proliferated within civil engineering in recent years is geographic information systems (GIS). The goal of a tool is to supplement ability and knowledge that already exists, not to serve as a replacement for that which is lacking. To secure the benefits and avoid misuse of a burgeoning tool, engineers must understand the limitations, alternatives, and context of the tool. The common benefits of using GIS as a supplement to engineering modeling are summarized. Several brief case studies of GIS modeling applications are taken from popular civil engineering literature to demonstrate the wide use and varied implementation of GIS across the discipline. Drawing from the case studies, limitations regarding traditional GIS data models and the implementation of civil engineering models within current GIS are identified and countered by discussing the direction of the next generation of GIS. The paper concludes by highlighting the potential for the misuse of GIS in the context of engineering modeling and suggests that this potential can be reduced through education and awareness. The goal of this paper is to promote awareness of the issues related to GIS-based modeling and to assist in the formulation of questions regarding the application of current GIS. The technology has experienced much publicity of late, with many engineers being perhaps too excited about the usefulness of current GIS. An undoubtedly beneficial side effect of this, however, is that engineers are becoming more aware of GIS and, hopefully, the associated subtleties. Civil engineers must stay informed of GIS issues and progress, but more importantly, civil engineers must inform the GIS community to direct the technology development optimally.     

Professional Design Component for Civil Engineering Curriculums

The Accreditation Board for Engineering and Technology has adopted a revised set of accreditation criteria that is designed to assure that graduates of accredited programs are prepared to enter the practice of engineering. The proposal also specifies that engineering programs must demonstrate that their graduates have an understanding of professional practice issues in addition to the ability to design civil engineering projects by taking various realistic constraints under consideration. The findings of this study indicate that engineering undergraduate and graduate students as well as practitioners perceive that three constraints that represent the traditional technical aspect of engineering are of great importance for design projects. They include engineering codes and standards, economic factors, and manufacturability (constructability). In contrast, two constraints received lower ratings. They include social ramifications and political factors. Overall, 60% of the Accreditation Board for Engineering and Technology recommended design constraints are rated by students and practitioners with a composite score ? 3.0. This may be interpreted as strong support for the Engineering Criteria 2000 design requirements.     

Dynamic Modeling of Large-Scale Magnetorheological Damper Systems for Civil Engineering Applications

Magnetorheological (MR) dampers are one of the most promising new devices for structural vibration mitigation. Because of their mechanical simplicity, high dynamic range, low power requirements, large force capacity, and robustness, these devices have been shown to mesh well with earthquake and wind engineering application demands and constraints. Quasistatic models of MR dampers have been investigated by researchers. Although useful for damper design, these models are not sufficient to describe the MR damper behavior under dynamic loading. This paper presents a new dynamic model of the overall MR damper system which is comprised of two parts: (1) a dynamic model of the power supply and (2) a dynamic model of the MR damper. Because previous studies have demonstrated that a current-driven power supply can substantially reduce the MR damper response time, this study employs a current driver to power the MR damper. The operating principles of the current driver, and an appropriate dynamic model are provided. Subsequently, MR damper force response analysis is performed, and a phenomenological model based on the Bouc–Wen model is proposed to estimate the MR damper behavior under dynamic loading. This model accommodates the MR fluid stiction phenomenon, as well as fluid inertial and shear thinning effects. Compared with other types of models based on the Bouc–Wen model, the proposed model has been shown to be more effective, especially in describing the force rolloff in the low velocity region, force overshoots when velocity changes in sign, and two clockwise hysteresis loops at the velocity extremes.     

Flexural Performance of Concrete Beams Reinforced with FRP Grids

This paper evaluates the flexural performance of simply supported concrete beams subjected to four-point monotonic loading and reinforced with a 2D fiber-reinforced plastic (FRP) grid. The main parameter of the study is the amount of longitudinal FRP reinforcement. With respect to a balanced strain condition, three underreinforced and two overreinforced FRP designs were tested with three identical beams per design. Laboratory recorded load-deflection, failure mode, cracking behavior, and reinforcement strain data are compared with theoretical predictions calculated according to traditional steel-reinforced concrete procedures. The study concludes that, with respect to ACI 318-95, flexural capacity is accurately predicted, but shear strength is not. Deflection compatibility between test results and ACI predictions employing the Branson effective moment of inertia was dependent on the percentage of longitudinal reinforcement. In general, observed flexural stiffness was less than that predicted by Branson's equation. A moment-curvature deflection procedure employing a bilinear concrete model compared very well with measured deflections. Finally, the grid configuration provides an effective force transfer mechanism. Cracking occurred at transverse bar locations only, and FRP tensile rupture was achieved with no observed deterioration in force transfer mechanics.     

Managing Computer-Aided Civil Engineering Design Services

Computer-aided engineering (CAE) technology is rapidly altering the design services delivery process. The implementation of this technology is affecting the management of design production as well as associated quality control activities. Many civil engineering managers do not recognize the organizational impact of this change. Among the numerous issues with which managers must deal in order to improve future company performance and maximize the benefit of CAE technology are: (1) the changing business environment; (2) the need to revise design production and quality control processes; (3) the identification of appropriate organizational structures; and (4) the effective management of human resources. Architect-engineering firms must develop a strategy to answer these questions if they are to remain competitive in the future. This paper suggests the basis for developing such a strategy.     

Standards in Civil Engineering Design Education

In the United States, requirements in the Accreditation Board for Engineering and Technology (ABET) engineering criteria provide a strong incentive to integrate engineering codes and standards into civil engineering undergraduate curricula. Under the current criteria, specifically Criterion 4, appropriate engineering standards must be incorporated into the major design experience. The purpose of this paper is to discuss the current ABET Engineering Criteria requirements with respect to engineering standards and suggest some ways standards can be included in both the technical and nontechnical portions of undergraduate curricula.     

Educating Students via Distance Learning for Civil Engineering Design

Two structural engineering courses were taught using distance-learning technology. One course was a graduate level, steel design course and the other was an undergraduate, elective, timber design course. Two-way live video and audio connections linked classrooms at San Jose State University and San Francisco State University. The interaction between student and teacher is discussed. These courses were the first time the California State University system offered students academic credit at either of two universities for a course taught via distance education from a single location. The challenges of teaching engineering design concepts via distance learning are discussed. Assessment of the teaching method was performed using student surveys and review of student grades. The assessment survey revealed that the students’ overall impression was positive. Grades received by the students at the Remote Site were lower than those at the Home Site, but this discrepancy may not have been a result of the distance-learning environment.     

Basic Study of Performance-Based Design in Civil Engineering

Although performance-based design, procurement, and construction management are now spreading rapidly in the building construction field, full-fledged study of the method for public works has barely begun. At this time, therefore, the concept expressed by the term “performance-based design” (which in this article, for simplicity, will include procurement and construction management) varies from person to person. This article is a basic study of the concepts of performance-based standards, performance-based standardization, and performance-based ordering, which are all necessary to introduce the performance-based design approach into the civil engineering field. It is proposed that performance-based design be defined in terms of two conditions: attainment level of objective of use, and degree of freedom. The article introduces the bottom-up and top-down methods as basic performance standardization methodologies.     

Tradition and Innovation in Teaching Structural Design in Civil Engineering

This paper briefly reviews the history of structural engineering education: The dawn, development, and consolidation of traditional education systems, as well as their fall into decline in the contemporary technological world. Recent graduates in civil engineering do not have all of the skills and knowledge that the labor market is demanding and civil engineering is losing the social prestige and professional recognition that our profession deserves. It is necessary to improve traditional education systems to produce the best civil engineers. The writers present a detailed discussion of their experiences teaching structural design at the School of Civil Engineering of Ciudad Real, Spain, using project-based and cooperative learning methods, as well as implementing knowledge management and transference to the learning process. Results and costs of these methods, as well as the problems related to faculty selection, are set out. The paper concludes with a reflection on the major educational possibilities and historical opportunities presented through the introduction of these new methods and suggest that this is the best way to combine engineering education and practice.     

Optimization of Blended-Elemental Powder-Based Titanium Alloy Extrusions for Aerospace Applications

The process of canless extrusion in ambient environment, using cold isostatic pressed, and vacuum-sintered, direct-consolidated blended-elemental hydrided ADMA titanium powder, mixed with master alloy powder for the Ti-6Al-4V composition, has been successfully demonstrated. However, these initially processed unoptimized powder-based extrusions also exhibited oxygen content of about 3000 ppm, within the ASTM B817 Standard, but exceeding the AMS Specification 4935 maximum limit of 2000 ppm, and with pre-extrusion residual hydrogen within 300–500 ppm resulting in post-extrusion void nucleation aligned with the extrusion direction. Additional optimization of extrusion billets during the CIP-and-sintering steps has been successfully demonstrated reducing both oxygen and hydrogen contents to levels at or below the AMS Specification limits for Ti-6Al-4V composition (oxygen content of 2000 ppm maximum, and hydrogen content of 125 ppm maximum). Processing-microstructure-property correlations of the optimized, AMS-4935-Specification-conformant, Ti-6Al-4V blended-elemental powder-based product form exhibited an overall mechanical property balance matching that of double-arc-remelted ingot-based extrusions. Property matching was not only in terms of static mechanical properties (room-temperature tensile properties, and monotonic fracture toughness K _IC (K _Q) values), but also in terms of dynamic fatigue properties (combined S/N plus da/dN properties), as well as stress-corrosion resistance, as measured in terms of K _ISCC threshold values.     

新建本科院校土木工程专业毕业设计质量保障体系

针对新建本科院校土木工程专业毕业设计面临的问题,以建筑工程方向为例,围绕如何提高本科毕业设计质量这一核心,探讨土木工程专业毕业设计教学的若干想法和实践,研究毕业设计在科学选题、过程管理、考核评价及师生培养等方面的质量保障措施。