Tallahassee, FL, United States
Tallahassee, FL, United States

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Herrera R.,05 Suwannee Street | Jones L.E.,05 Suwannee Street
Transportation Research Record | Year: 2016

This case study summarizes the design, construction, load testing, and integrity testing of nonredundant drilled shafts for a bridge project in northwest Florida. The subsurface profile consisted mainly of calcareous sandy and silty clay (marl and marlstone) interfingered with limestone and cemented sand layers. The results of unconfined compression tests revealed significant variability in strength, with strata within the depth of interest holding strength properties that fall within the generally accepted range of cohesive intermediate geomaterial. This paper discusses local geology, geotechnical investigation, design, construction, load testing, and site-specific correlations. Important aspects of the project, including the use of the shaft inspection device to examine the cleanliness of the bottom of the shafts, Osterberg cell load testing, and the site-specific correlations developed from the results, as well as integrity testing with cross-hole sonic logging and a thermal integrity profiler, are presented. The inability of the standard penetration test (SPT) to delineate boundaries adequately between strong and (relatively) weaker layers is presented, as well as nonlinear site-specific relationships between anticipated skin friction resistance and SPT blow count. The nonlinear SPT-based relationships attempt to address the strain incompatibility between strong and weak seams that may exist within a given stratum. Proposed correlations for skin friction and end bearing that are based on laboratory strength testing are presented in terms of revised unconfined compressive strength to address variability in strength characteristics across the site. © 2016, National Research Council. All rights reserved.

Inkoom S.,Florida State University | Sobanjo J.O.,Florida State University | Thompson P.D.,Florida State University | Kerr R.,05 Suwannee Street | Twumasi-Boakye R.,Florida State University
Transportation Research Record | Year: 2017

The AASHTO Pontis bridge management system has been used to support network-level and project-level decision making on the condition and functional obsolescence of bridges. State departments of transportation often develop bridge inspection data collection methods, deterioration models, cost models, and other preservation analysis capabilities to comply with the requirements of the federal Government Accounting Standards Board. The bridge health index (BHI) in the Pontis bridge management system has been used in the evaluation of the condition of bridges and elements at the project and network levels. This paper investigates three issues in the computation of the BHI: The effects of using linear and nonlinear scales for the condition state weights when computing the element health index (EHI); the application of amplification weights to EHI values to emphasize bridge elements in bad condition; and the development of element weights based on element replacement costs, element long-Term costs, element vulnerability to hazard risks, and a combination of these measures. Historical condition data from element-based inspection were used to evaluate these effects at the network level.

Sobanjo J.,Florida State University | Thompson P.,17035 Northeast 28th Place | Kerr R.,05 Suwannee Street
Transportation Research Record | Year: 2013

The state of Florida is developing a risk-based decision support model, specifically for its state-maintained bridges, to handle the occurrence of natural hazards, such as hurricanes, tornadoes, floods, landslides, and wildfires. Many bridges in Florida are vulnerable to damage caused by these hazards. With a focus on hurricanes, this paper develops prediction models (estimates of likelihoods) based on historical data of hazard events in Florida, as well as on existing national models. The Poisson process was assumed for the occurrence of natural events; predictions were estimated for the annual probability of occurrence. It was observed that, on average, the probability of hurricane occurrence at bridge locations decreased with the hurricane intensity (category number). In comparison, wildfires, another common hazard, had the highest likelihood estimates of the natural hazards. With a focus on physical damage to bridges, the consequences of hurricanes were also estimated on the basis of historical data within Florida. The damaged bridge components and elements were identified, and the levels of damage and the associated repair costs were assessed.

Thompson P.,17035 Northeast 28th Place | Sobanjo J.,Florida State University | Kerr R.,05 Suwannee Street
Transportation Research Record | Year: 2013

The Florida Department of Transportation (DOT) has developed a set of risk models for its bridge management system; the models are built into its existing Excel-based project-level and network-level decision support tools and are intended for eventual use in AASHTO's Pontis 5.2. One of these new models is an analysis of the risk associated with advanced deterioration. This model extends the reach of Florida's existing deterioration models to estimate the likelihood of service disruption if a badly deteriorated element should be unrepaired. The Florida DOT maintains data about demolished and replaced bridges as inactive records in its Pontis database. The condition and characteristics of the removed bridges were statistically analyzed to explore the reasons for the end of each bridge's life. On the basis of the available data, including information on load posting and reconstruction, the likelihood of service disruption was reasonably quantified. The best models developed in the research used a combination of linear and lognormal forms and reflected the buildup of risk caused by repeated Markovian deterioration as well as the typical delay that occurred between the observation of the deteriorated conditions and the resulting action to replace or reconstruct the bridge. As a by-product of the research, a linear failure probability model was developed; the model is suitable for Pontis releases up to 4.5. This model will be helpful to bridge owners who do not have their own source of estimates for the probability of bridge element failure.

Tran K.T.,University of Florida | Mcvay M.,University of Florida | Herrera R.,05 Suwannee Street | Lai P.,05 Suwannee Street
Canadian Geotechnical Journal | Year: 2012

A technique is presented to estimate static tip resistance of a pile during driving from embedded strain and accelerometer data located one diameter (D) from the bottom of the pile. The approach uses a nonlinear single degree of freedom system to satisfy force and energy equilibrium with a global genetic inversion approach. By balancing force and energy from inertia, damping, and stiffness against the measured tip data, the unknown parameters (mass, damping, and nonlinear stiffness) are estimated. Requiring a few seconds for analysis for each blow, the algorithm ensures a real-time assessment of static tip resistance as a function of displacement, which is important when setting pile lengths. The proposed approach was applied to four test piles at two bridge sites (Florida and Louisiana). Mobilized static tip resistances ranging from 400 to 1500 kN as a function of displacement were predicted. The predicted static resistance versus displacements compared favorably with measured values from static load tests. Interestingly, the maximum recorded increase in tip resistance in silty to clayey sands was less than 20% when piles were re-struck at times ranging from 2 to 30 days after initial drive.

Theiss L.,Texas A&M University | Miles J.D.,Texas A&M University | Ullman G.L.,Texas A&M University | Maxwell S.D.,05 Suwannee Street
Transportation Research Record | Year: 2014

This report documents the efforts and results of several photometric evaluations performed by researchers at the Texas A&M Transportation Institute to assess the performance of steady-hum warning lights in temporary traffic control devices used to delineate the correct travel path in work zones. The research included an assessment of the potential incremental Increase in luminance (and benefit of that increase to drivers) during vulnerable driving conditions. These conditions included periods of heavy fog, periods when dirt and grime had accumulated on the channelizing device, and misalignment of warning lights. The researchers found that fog adversely affected the apparent luminance (and thus the visibility distance) of both retroreflective sheeting and warning lights. However, retroreflective sheeting was still likely to be visible at distances needed for purposes of path guidance and delineation, and the use of warning lights was unlikely to provide much additional value to motorists. The researchers also found that the accumulation of dirt and grime on the retroreflective sheeting of drums in Florida work zones did have an impact on device luminance. Although the use of warning lights did increase the overall luminance of channelizing drums, a greater increase in luminance was noted when the drums were clean. Finally, misalignment of lights significantly reduced their photometric value.

Theiss L.,Texas A&M University | Pratt M.R.,Texas A&M University | Ullman G.L.,Texas A&M University | Maxwell S.D.,05 Suwannee Street
Transportation Research Record | Year: 2014

The 2009 Manual on Uniform Traffic Control Devices recognizes the potential safety benefit of providing enhanced delineation on temporary traffic control devices and allows for warning light enhancements on channelizing devices and temporary barrier walls. The argument for using warning lights in work zones is that they provide an incremental benefit to safety. Ideally, the additional costs of using warning lights should be offset by that safety benefit; in other words, the reduction in crash costs should equal or exceed the costs of the devices. In this study, the researchers collected and analyzed data on the cost of steady-burn warning lights, computed the increases in crash costs that could be expected to occur in two types of work zones, and computed the reductions in crash costs (i.e., safety benefits) that would have to occur from the use of the steady-burn warning lights to justify their use on a benefit- cost basis. On the basis of the results of this cost-effectiveness evaluation, the researchers recommend that the use of steady-bum warning lights in work zones be discontinued.

Sokolow G.,05 Suwannee Street | Williams K.,University of South Florida | Levinson H.,Ashlar Village
Access Management Theories and Practices - Proceedings of the 2nd International Conference on Access Management, AM 2014 | Year: 2014

This paper seeks to demonstrate the importance of expanding the orientation of access management of the major roadway system beyond the goals of maintaining high-speed through movement. Speeds can be managed without increasing congestion. The paper also addresses how access management and design can better relate to pedestrians, bicyclists, and public transportation. The profession must be more aware of the land use and community context, where access management techniques are being applied. Context changes over time and it also changes by location. Therefore, the same approach will not be appropriate on all segments of a roadway or in all countries or regions. A change in the focus of access management with regard to context is consistent with recent trends in transportation and urban planning. © ASCE.

Packard C.,05 Suwannee Street | Vollmer D.,05 Suwannee Street | Summary P.,05 Suwannee Street
21st World Congress on Intelligent Transport Systems, ITSWC 2014: Reinventing Transportation in Our Connected World | Year: 2014

Video on desktop (VOD) provides the Florida Department of Transportation (FDOT) with a means to control closed-circuit television (CCTV) cameras operations and their videos directly from an operator's workstation desktop. This provides great benefit by clearing much needed space on the video wall to display roadway and ITS information.

Clark P.,05 Suwannee Street | Packard C.,05 Suwannee Street
21st World Congress on Intelligent Transport Systems, ITSWC 2014: Reinventing Transportation in Our Connected World | Year: 2014

The container number database (CNDB) stores commercial vehicle identification numbers (CVIDN), including container numbers, license plate numbers, and United States Department of Transportation (USDOT) numbers read at weigh stations and agricultural interdiction stations. It also provides retrieval and display of this data to users authorized by the Florida Department of Transportation's (FDOT) Commercial Vehicle Operations (CVO) Program. The CNDB also stores out-of-compliance lists from multiple agencies and individual users to identify sightings of CVIDNs of interest. It uses a target file containing out-of-service vehicles provided by USDOT's Performance and Registration Information Systems Management (PRISM) and an overdue citations hotlist provided by the Department of Highway Safety and Motor Vehicles, Florida Highway Patrol (FHP) computer-aided dispatch. CNDB users can also add custom out-of-compliance lists for CVIDNs.

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