Journal of Performance of Constructed Facilities

The purpose of this investigation was to conduct a laboratory test program on how much induced vibrations on concrete during the period between initial set and final set affect the attainable strength of concrete. To achieve this purpose, a laboratory test program was conducted. The laboratory program consisted of casting 144 $76\mathrm{mm}$ by $152\mathrm{mm}$ $(3\times 6\mathrm{in.})$ concrete cylinders and subjecting them to one of two levels of vibration for either 1 or $2\min$ at five different ages ranging in time from before, during, and after the setting period for the concrete. The levels of vibration correspond to typical frequencies of vibratory soil compactors and the peak particle velocity produced by the compactors. Both compression and splitting tensile tests were performed. The results of the laboratory study indicate that vibratory soil compaction should not be considered a significant hazard to foundation strength as long as the vibrations are within the limits in this study.

A curved, three-span continuous, steel I-girder bridge in Salt Lake City was tested in order to determine its dynamic and static load carrying properties for three boundary condition states. For each of the three boundary condition states, two dynamic forced vibration methods were applied to the bridge as well as a static live-load test. The first forced vibration method used an eccentric mass shaker. The second method involved striking the side of the bridge with an impact hammer. The live-load test was performed by slowly driving a truck at a crawl speed across the bridge. Velocity transducers, accelerometers, and strain gauges were utilized to record the response of the bridge. The analysis and compilation of recorded dynamic response of the bridge enabled the preparation of mode shapes and natural frequencies for each boundary condition. This paper discusses the resulting changes in relevant dynamic properties and compares them with the changes in the static properties that were determined from the bridge response recorded from the live-load tests.

High mast lighting structures are being used to provide illumination for large intersections, particularly for highways located in rural areas. These structures, ranging from approximately $15–40\mathrm{m}$ $(50–130\mathrm{ft})$ in height, are exposed to high wind forces that in turn produce a tremendous number of loading cycles each year. A recent high mast lighting structural support failure in the high plains of Colorado near Denver International Airport provided the impetus for this study. These high-mast structures are less than one meter $\left(3.28\mathrm{ft}\right)$ in diameter and are quite flexible relative to many civil engineering structures. This flexibility results in large deformations when compared to their diameter, i.e., when combined with the height of these structures. Furthermore, large forces and moments at the base are produced that result in large stresses and stress reversals during multimode excitation. This paper presents the process and results for the development of a reliability-based design procedure for high-mast lighting structural supports based on fatigue life. The resulting procedure is prescriptive in that a series of design charts result from full nonlinear finite element analysis. The loading on the slender body is characterized by Morison’s equation, essentially providing the nonlinear loading relationship for the wind on the moving structure. Then, a well-known random vibrations approach was coupled with Miner’s rule to estimate the fatigue life of the structural support. Several illustrative design examples are presented and shown to compare very well with full simulations.

Tire chips (or shredded tires) have been successfully used as a filler material in a number of embankments, but this use has also led to problems such as spontaneous combustion, settlement, and so on. To ensure proper construction and to avoid such problems, the Texas Department of Transportation sponsored a study to monitor the performance of embankments constructed of tire shred fill material in El Paso, Texas. Three embankments, consisting of (1) a mixture of soil and shredded tires; (2) shredded tires wrapped in a geotextile; and (3) a reference embankment built with conventional soil, were instrumented and monitored. The performance of the embankments in terms of vertical settlement, temperature change, and air and water constituency changes were monitored. The performance of these three embankments has shown that there is little potential for environmental impacts in a climate like that of El Paso, and that the construction techniques employed limited the settlements in comparison with some previous experiences.

Nondestructive testing techniques have been historically and commonly used to evaluate the quality of existing concrete structures. Several traditional nondestructive testing techniques were applied to the pier caps of the Quebec Street Bridge over Air Lawn Road, constructed in 1971, which is located in Denver, Colorado. The techniques utilized included visual inspection, hammer sounding, Schmidt hammer rebounding, and ultrasonic pulse velocity testing, including tomographic imaging. Results of the nondestructive tests were used to determine areas to be tested with local destructive tests. These tests included concrete compressive strengths, chloride testing, and petrographic testing. This paper presents the application and interpretation of common nondestructive testing techniques and the consequent repair, rehabilitation, and maintenance decisions. The overall results indicate that inside cores of all the pier caps are healthy, sound concrete. On all of the pier caps, extensive exterior concrete layer rehabilitation needed to be completed.

In 2003 the Ohio Department of Transportation (ODOT) implemented a new culvert management program. Simultaneously, a team of researchers from the Ohio Research Institute for Transportation and the Environment (ORITE) and engineers from a private consulting firm conducted a joint study to evaluate the effectiveness of field culvert inspection and rating procedures proposed by the ODOT’s new program and describe the best remedial measures currently available for highway culverts. This paper focuses on the first component and addresses it relative to concrete culverts. The new inspection procedure for concrete culverts was applied at 25 sites. Inspection data were examined to detect common problems existing at concrete culvert sites in Ohio. The field data were also analyzed using statistical software to identify factors that contribute to the degradation of concrete culverts. Despite the limited amount of data, the results indicated that the ODOT approach was basically sound. The final segment of the paper presents a risk assessment method developed by the ORITE researchers. The proposed risk assessment method computes the overall structural health rating for any inspected culvert and recommends a course of action.

Reports of failure of existing concrete structures due to a lack of durability, rather than a deficiency in structural strength, has made concrete technologists, engineers, and researchers focus research on the parameters influencing durability performance with respect to time. Systematic performance monitoring, with respect to chosen durability parameters of existing concrete structures, will decide the direction of future research in this area. Inferences based on laboratory simulations and testing need to be confirmed by in situ field measurements and studies. In situ condition rating and performance monitoring surveys have been conducted by many researchers, scientists, and professional associations, and reported in literature. Inferences of few such studies are summarized and discussed. Deterioration of concrete structures constructed in recent times is observed at relatively faster rates, and has been mainly attributed to cracking. Cracking is associated with the use of faster-hydrating portland cements with increased fineness and the tricalcium silicate $\left({\mathrm{C}}_3\mathrm{S}\right)$ content to support the high speed of modern construction. In the present research, a case study of deteriorated water tank structures situated in the semitropical region of India is presented. Some selected parameters—such as concrete cover, carbonation depth, chloride concentration, compressive strength, etc. which influence long term durability of structures—have been measured.

This paper describes an automated and integrated detection, structural assessment, and rehabilitation method selection system for sewers based on the processing of video footage obtained by closed circuit television surveys. The system is based on a neural network classifier (NNC) trained to identify longitudinal cracks in sewers. Results obtained from experimentation with the NNC indicate that crack detection based on single-frame processing is not sufficient, and frame sequence processing substantially improves crack recognition rates. Based on the location of the cracks, local and global structural damage is assessed and a rehabilitation method is selected. Based on the significance of damaged sewers, the rehabilitation projects are being prioritized. An expert system coordinates the various modules in the system and connects them to a geographic information system.

The City and County of Denver (CCD) and the University of Colorado Denver have been involved in cooperative research since 1997. Although a variety of projects have been completed, the main deliverable has been a comprehensive geographic information system database containing both major and minor infrastructure. Major infrastructure includes assets such as bridges and streets, while minor infrastructure includes alleys and street subsystems, such as curbs, gutters, inlets, sidewalks, driveways, cross-pans, and handicap ramps. This paper presents the equipment, methodology, results, and applications based on the inventory and analysis of the CCD’s concrete curb and gutter infrastructure. In summary, approximately 3,300 lineal mi $\left(\mathrm{5,280}\mathrm{km}\right)$ of curb and gutter were inventoried and inspected over a period of three years at a cost to the CCD of approximately $100 per mile.