Robert Bolton

Field Verification of the Damage Index Method in a Concrete Box‐Girder Bridge via Visual Inspection

The structural condition of a concrete box-girder bridge is monitored twice by detecting and localizing potential damage in the bridge superstructure. Experimental field data were collected on the bridge in December 1997 and 9 months later in September 1998. Modal parameters for the structure are extracted from the measured frequency-response functions, and the resulting resonant frequencies and modeshapes are fed into a proven systems identification procedure. Modal parameters from the identified baseline structure and the modal parameters determined in the field are used as input to a field-tested nondestructive damage-evaluation method (the damage index method) to localize damage in the bridge superstructure. To provide some evidence of the veracity of the predictions of the possible damage locations, a visual inspection was performed on the bridge in May 1999, and surface cracks on the deck were recorded. A comparison of the predicted damage locations on the superstructure with the surface cracks documented via visual inspection is provided. The results indicate that a strong correlation exists between the predicted damage locations and the observed surface crack pattern.

Documentation of Changes in Modal Properties of a Concrete Box-Girder Bridge Due to Environmental and Internal Conditions

This paper presents the results of 2 modal tests performed on a concrete box-girder bridge. The 2 modal tests were performed sequentially with a 9-month time interval between tests. This sequence of tests form the initial phase of a modal-based level IV nondestructive damage-evaluation process implemented to establish the rate of structural deterioration and remaining service life of the tested structure. A level IV process detects, locates, and sizes damage and determines the impact of the damage on the performance of the structure. A novel feature of the field testing is the execution of an incremental and minimally intrusive (to traffic flow) modal test procedure. The instrumentation, experimental test plan, and resulting modal analysis are discussed. The changes in the 2 modal data sets are also discussed.

An integrated first-year engineering curricula

The Foundation Coalition (FC) Program at Texas A&M University (USA) includes chemistry, English, engineering, math and physics taught in an integrated two semester sequence using technology and delivered in an active-collaborative environment to students working in teams of three and four. A unique feature of the courses taught at A&M is the close coordination of subject matter maintained by the first-year faculty teaching team. Topics covered in each discipline are discussed in weekly meetings and efforts are made to teach and reinforce concepts across subject lines. The paper addresses some of the challenges encountered in an integrated program (such as, students with previous college credit in one or more area, and students with differing levels of academic preparation). The authors believe that their thrusts of integration, teaming, active learning and technology will produce engineers who can solve increasingly complex problems more effectively.

Engineering graphics in an integrated environment

This paper focuses on the freshman year of the Foundation Coalition program at Texas A&M University. The curriculum includes chemistry, English, engineering, math and physics taught in an integrated just in time fashion using technology and delivered in an active-collaborative environment to students working in teams of four. Through our thrusts of integration, teaming, active learning and technology we hope to produce engineers who can solve increasingly complex problems more effectively. Graphical analysis, not generally taught or used by engineering students, has provided the best avenue for integration of graphics into the freshman Coalition environment. Graphical analysis techniques introduce CADD (Computer Aided Design and Drafting) to the student in a manner that reaches graphical fundamentals and at the same time is relevant to topics addressed in other course work. Examples include: graphical solutions to vectors are used to introduce the concept of coordinate systems and scale; and traditional topics in descriptive geometry have been replaced with an introduction to 3D model development. Another area where graphics provides a valuable interface is in developing communication skills. Integrated technical reports, produced by student engineering design teams, include technical content (graded by science, mathematics, and engineering faculty) and are submitted to English.

An innovative industry-sponsored "semiconductor initiative"

This paper discusses an innovative curriculum impact by the semiconductor industries on the curriculum, applied research and future direction of the Engineering Technology and Industrial Distribution Department at Texas A&M University. Semiconductor industries are growing at a rate higher than can be implemented by the current industrial workforce. There exists a growing need for individuals who can deliver new technologies to increase the competitiveness of the industries in the State. High quality application engineers properly trained in this area are one of the key assets required in maintaining this competitiveness. To address these requirements, multiple educational grants have been funded to implement a new program emphasis in Semiconductor Manufacturing Engineering Technology (SMET) within the Department of Engineering Technology in the College of Engineering at Texas A&M University. The evolution and widespread development of high technology semiconductor equipment and processes require an increased attention to the areas of engineering support. Among these, but not all-inclusive are: field service equipment engineering, test engineering, software engineering, and wafer-fab engineering. This proposed program in the College of Engineering at Texas A&M University would represent the only program at a major university for educating personnel for this distinctive career path. Because of the growing importance of semiconductor equipment manufacturers and high-tech electronics in Texas, such a development has the potential to make the College of Engineering an exemplary benefactor for the state of Texas and the nation.

Measuring bridge performance using a structural health monitoring system

Advanced composite materials are widely recognized to be an effective material for the strengthening of structures subjected to seismic events. These materials are also being investigated as a potential rehabilitation technique to increase the live-load capacity of a bridge. While there are benefits to this technique, there are limitations as well, such as a lack of long-term performance data. Performance is taken here to include serviceability, reliability and durability. This paper will demonstrate how a structural health monitoring system can be utilized to determine measures of performance for a bridge rehabilitated using advanced composite materials. First, the theoretical framework of the health monitoring system will be developed. Next, the philosophy and design of the composite rehabilitation will be described. As part of the monitoring process, the bridge will be tested prior to beginning the rehabilitation work to verify the base line condition. After the rehabilitation work is completed, data will be collected on a periodic basis and the results evaluated to determine the performance of the bridge was improved.

Embedded real-time controls through application

The laboratory portion of real-time controls offers the students the opportunity to apply the control systems theory developed in the classroom via hardware and software tools commonly used in industry such as a microcontroller, sensors, motors, Matlab, Simulink and C programming. Once exposed to the usage of the tools, the students then undertake the design and implementation of real time control of an autonomous vehicle. Using this approach the students not only learn the application of the theory presented in lectures, but the students also experience the system design process, thus refining their creativity, problem solving ability, and teaming skills. As a result, the students preparation for industry is greatly enhanced.

A nontraditional course in electromechanical systems for engineering technologists

Texas A&M University teaches a required course in electromechanical systems to sophomore and junior mechanical and electrical engineering technology majors. The course transitions students from calculus and physics perquisites to more advanced courses in design, applied vibrations, automation, and industrial/real-time controls. Students study analysis and modeling of dynamic mechanical, electrical and mixed systems using classical methods and simulation. This class must introduce students to advanced engineering topics at levels ideally matched to student abilities to assimilate the material. The intent of this paper is to discuss several innovative laboratory and instructional approaches used to introduce topical materials to such a mixed student audience. Topics are initially taught using a systems or component assembly approach emphasizing the need to identify and model the individual components of larger systems. Students then directly assemble component models into one or more differential equations based on governing physical laws. These equations are numerically simulated and system response characteristics investigated. After some experience in evaluation of various dynamic systems is accomplished classical time and frequency solutions of linear 1st and 2nd order linear differential equations are presented and tied back to the earlier course material. The common mathematical solution processes integrated in the course are intended to act as a unifying force in developing an understanding of cross-disciplinary engineering problems.