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West Side Highway, United States

Chen L.,Professional Service Industries Inc. | Graybeal B.A.,Turner Fairbank Highway Research Center
Journal of Bridge Engineering

The concrete-damaged plasticity (CDP) model with proposed material properties replicated the observed deflection and strain responses of three experimentally tested I-girders and was determined to be consistent for different spans under both flexural and shear tests. In this study, the CDP model was further tested in modeling the behaviors of a prestressed second-generation ultrahigh-performance concrete (UHPC) pi-girder. The computational aspects include discussion of the various parameters that influenced the accuracy of the model and investigation of the scenarios regarding the limits that are useful for further optimization of the girder. The CDP model was reconfirmed to be consistent and reliable in replicating the observed structural response of both the UHPC pi-girder and a modified structural configuration referred to as the "UHPC pi-girder-with-joint. " The finite-element analysis modeling techniques developed herein are expected to be valuable in the future development of additional UHPC structural components. © 2012 American Society of Civil Engineers. Source

Xue W.,Virginia Polytechnic Institute and State University | Weaver E.,Turner Fairbank Highway Research Center
Transportation Research Record

FHWA conducted controlled loading tests on the US-23 test road in hot weather conditions in Ohio. The tests used four tire types in both dual and wide-base configurations, which were fitted on a single unit two-axle truck, maintaining a constant gross vehicle weight. Two pavement sections, one 8 in. (200 mm) and one 4 in. (100 mm) thick, were instrumented with strain gauge rosettes oriented vertically to measure strain traces induced from the passing wheel loads at three speeds and tire inflation pressures. Pavement temperature was monitored with depth during testing as well as wheel track offset distance from the strain sensors. Because of time constraints, only the sensors in the plane parallel to the direction of loading were analyzed, and response data were compared only with linear elastic pavement response models. The as-measured data were processed and evaluated for all rosettes oriented in the direction of loading. Stress relaxation modulus data were used to adjust the pavement modulus to a common temperature and loading time so all measured data could be compared at the same loading conditions. The WinLEA linear elastic model was used to determine the relationship of structural modulus to strain. Lateral offset distributions were determined from measured data to adjust all strains to the offset where maximum strain response is observed in the as-measured data. The adjustments were then applied to the as-measured strain data to make consistent comparisons between tires. Three of the four tire configurations produce nearly equivalent pavement response, which was attributed to similarities between the tire footprint widths. Source

Li X.,Turner Fairbank Highway Research Center | Gibson N.,U.S. Federal Highway Administration
Asphalt Paving Technology: Association of Asphalt Paving Technologists-Proceedings of the Technical Sessions

This study investigated the feasibility of performing dynamic modulus and fatigue performance tests using reduced scale specimens in an Asphalt Mixture Performance Tester. Ten different mixtures were characterized which had different nominal maximum aggregate sizes and were laboratory prepared or field cored from accelerated pavement test sections. Indirect tension dynamic modulus was included in the characterization of the field cored materials. An aspect ratio for 38 mm diameter specimens was recommended based on an exploratory portion of the study. The experimental results show that the modulus of the small scale specimens can be quite similar to the full size specimens and tends to be slightly softer at high temperature and low reduced frequencies. Phase angle is more comparable and, when different, tends to be slightly higher for the small scale specimens. Data analysis comparing the full size and small scale specimens revealed two out of three data quality indicators from small size dynamic modulus are as good as that of full size dynamic modulus. The third quality indicator was worse for about one third of the data points, but the majority of tests satisfied recommended values. The fatigue test results showed the modulus reduction at failure and endurance limit are comparable between full size and small scale specimens. There was no consistent trend where small scale was larger or smaller than full scale specimens in fatigue resistance and the ranking was mostly preserved between the two sized specimens. Overall, the small scale approach is very promising which can allow the field-compacted fatigue and stiffness characteristics of pavements to be assessed. The applications of this research are field validation of cracking tests, performance based quality assurance and forensic investigations. © 2013 Taylor & Francis. Source

Li X.-J.,Turner Fairbank Highway Research Center | Marasteanu M.O.,University of Minnesota
Proceedings of the Society for Experimental Mechanics, Inc.

This work presents a repeatable semi circular bending (SCB) fracture test to evaluate the low temperature fracture resistance of asphalt mixture. The fracture resistance of six asphalt mixtures, which represent a combination of factors such as binder type, binder modifier, aggregate type, and air voids, and two testing conditions of loading rate and initial notch length, was evaluated by performing SCB fracture tests at three low temperatures. Fracture energy was calculated from the experimental data. Experimental results indicated strong dependence of the low temperature fracture resistance on the test temperature. Experimental plots and low coefficient of variation (COV) values from three replicates show a satisfactory repeatability from the test. The results of the analysis showed that fracture resistance of asphalt mixtures is significantly affected by type of aggregate and air void content. Experimental results, also confirmed the significance of binder grade and modifier type with relation to cracking resistance of asphalt mixtures. Analysis of result also indicated that both the loading rate and initial notch length had significant effect on the fracture energy at the highest test temperature, whereas the effect was strongly diluted at the two lower temperatures. No clear trend was found with the fracture peak load from either the effect of loading rate or notch length. © Society for Experimental Mechanics 2009. Source

Duwadi S.R.,Turner Fairbank Highway Research Center
Public Roads

A Federal Highway Administration (FHWA) program reports on its 12-year track record of developing technologies and methodologies to restore and preserve historic covered bridges. In June 1998, the Transportation Equity Act for the 21st Century (TEA-21), as amended by the July 1998 TEA 21 Restoration Act, established the National Historic Covered Bridge Preservation Program. Funding for the program became available in 2000. Administered by the FHWA, the covered bridge program had two key components. One was the award of grants to States through annual solicitations for preservation, restoration, and rehabilitation work. The other was for research, development, and education. The research and development research and development component focused on the development of methodologies that use an appropriate blend of new and traditional techniques to restore and protect these historic structures. FHWA conducted the research, development, and education portion of the program through a partnership and close collaboration with the US National Park Service Historic American Engineering Record (HAER) and with the US Department of Agriculture (USDA) Forest Service Forest Products Laboratory. Source

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