The objectives of this research were to 1) investigate bridge deck condition assessment methods used in the field and laboratory, methods of managing bridge decks, and methods for estimating remaining bridge deck service life using computer models through a comprehensive literature review on these subjects; 2) collect and analyze field data from representative concrete bridge decks in Utah; and 3) develop a decision tree for concrete bridge deck management in Utah. As a result of the literature review performed for objective 1, a synthesis of existing information about condition assessment, bridge deck preservation and rehabilitation, bridge deck reconstruction, and estimating remaining service life using computer models was compiled. For objective 2, 15 bridge decks were strategically selected for testing in this research. Five bridge decks had bare concrete surfaces, five bridge decks had asphalt overlays, and five bridge decks had polymer overlays. Bridge deck testing included site layout, cover depth measurement, chloride concentration testing, chain dragging, half-cell potential testing, Schmidt rebound hammer testing, impact-echo testing, and vertical electrical impedance testing. Two-sample t-tests were performed to investigate the effects of selected bridge deck features, including polymer overlay application, deck age at polymer overlay application, overlay age, asphalt overlay application with and without a membrane, stay-in-place metal forms (SIPMFs), SIPMF removal, internally cured concrete, and use of an automatic deck deicing system. For objective 3, condition assessment methods were described in terms of test type, factors evaluated, equipment cost, data collection speed, required expertise, and traffic control for each method. Unit costs, expected treatment service life estimates, and factors addressed for the preservation, rehabilitation, and reconstruction methods most commonly used by the Utah Department of Transportation (UDOT) were also summarized. Bridge deck testing results were supplemented with information about current bridge deck management practices and treatment costs obtained from UDOT, as well as information about condition assessment and expected treatment service life, to develop a decision tree for concrete bridge deck management. Based on the results of field work and statistical analyses, placing an overlay within a year after construction is recommended. Removing SIPMFs after a deck age greater than 18 years is not likely to be effective at reversing the adverse effects of the SIPMFs on bridge deck condition and is not recommended. Bridge deck construction using internally cured concrete is not recommended for protecting against rebar corrosion. To the extent that excluding an automatic deck deicing system does not compromise public safety, automatic deck deicing systems are not recommended. To supplement the typical corrosion initiation threshold of 2.0 lb Cl-/yd3 of concrete for black bar, a corrosion initiation threshold of 8.0 lb Cl-/yd3 of concrete is recommended in this research for bridge decks with intact epoxy-coated rebar. For chloride concentrations less than 20 lb Cl-/yd3 of concrete as measured between reinforcing bars, an increase of up to 70 percent should be applied to estimate the corresponding chloride concentration of the concrete in direct contact with the rebar. The decision tree developed in this research includes 10 junctions and seven recommended treatments. The junctions require the user to address questions about surface type, degree of protection against water and chloride ion ingress, degree of deterioration, and years of additional service life needed; the answers lead to selection of treatment options ranging from repairing an overlay to full-depth bridge deck reconstruction. Revisions to the decision tree should be incorporated as additional methods, data, treatments, or other relevant information become available.

As part of the Long-Term Bridge Performance (LTBP) program, a flagship research program funded by the Federal Highway Administration in response to the aging bridge network, the Lambert Road Bridge near Elk Grove California was selected as the California Pilot bridge set to undergo non-destructive testing and monitoring. The purpose of the program is to obtain a database of scientific quality data concerning the health and maintenance procedures currently in use across the nation. FHWA program managers along with members of the Utah State University LTBP research team selected the bridge with the assistance of the National Bridge index and site visits. Dynamic modal analysis and long-term health monitoring are two of the test procedures that the test bridge will undergo. Dynamic modal analysis is performed by introducing a known vibration into the system and recording the response. The dynamic properties are extracted in this manner, which allows any changes in the structure to be tracked over time as the dynamic properties change. The long-term health monitoring of the bridge will include an array of sensors designed to capture the real-time structural response of the bridge under normal operating conditions at key locations. An array of 1-Hz Velocity Transducers was used to record the bridge response to the introduced vibrations. The data collected over 4 days of testing was analyzed using the "peak picking method" to locate the resonant frequencies, mode shapes, and damping ratios of the structure. In this thesis the dynamic testing results and the finite element model were compared and correlated both visually and with a modal assurance criterion. The long-term health monitoring is also discussed in this thesis. The types and reason for each sensor are presented and the installation procedure is explained and documented.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18519号 / 工博第3911号 / 新制||工||1601(附属図書館) / 31405 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 白土 博通, 教授 宮川 豊章, 教授 八木 知己 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21081号 / 工博第4445号 / 新制||工||1691(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 杉浦 邦征, 教授 KIM Chul-Woo, 教授 清野 純史 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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Short span bridges are commonly used throughout the United States to span small waterways and highway overpasses. New technologies in the civil engineering industry have aided in the creation of many unique designs of these short span highway bridges in efforts to decrease construction cost, decrease maintenance costs, increase efficiency, increase constructability, and increase safety. Three innovative systems, the Integral Abutment Bridge, “Bridge-in-a-Backpack”, and the Folded Plate Girder bridge will be analyzed to study how the bridges behave under various types of loading. Detailed finite element models were created for integral abutment bridges of varying geometry. These models are used to study how the live load distribution transversely across the bridge is effected by varying geometric properties and varying modeling techniques. These models will also be used to determine live load distribution factors for the integral abutment bridges and compare them to current American Association of State Highway and Transportation Officials specifications. The “Bridge-in-a-Backpack” and the Folded Plate Girder bridges were each constructed with a variety of instruments to measure the bridge movements. Readings from these instruments are used to determine the bridge response under various loading conditions. Bridges were analyzed during their construction process, during static live load testing, and during long term seasonal changes. The results from these studies will aid in the refinement of these innovative designs.

The objective of the research presented in this thesis was to develop a concrete bridge deck topping mixture that resists the effects of differential shrinkage by decreasing shrinkage and increasing creep. . In addition, the amount of tensile creep that concrete experiences under long-term tensile stresses were quantified and compared to compressive creep values in order to gain a better understanding of how concrete behaves under tension. Test results show that the amount of tensile creep exceeded compressive creep by a factor of 2-5. Various shrinkage and creep models were compared against test data in order to quantify results and determine the best model to use for the mixes examined during this research project. Data analysis revealed that the AASHTO time dependent effects (shrinkage and creep) models outperformed the other models used in this research project. Other material property data including compressive strength, splitting tensile strength, Young's modulus of elasticity, and unrestrained shrinkage was also collected to compare against a common bridge deck topping mix to ensure that the mixes used in this research project are suitable for use in the field. A parametric study utilizing the Age Adjusted Effective Modulus (AAEM) method was performed which showed that the most important factor in reducing tensile stresses was to decrease the amount of shrinkage experienced by the concrete bridge deck topping mixture. Three concrete mixtures, one included saturated lightweight aggregates (SLWA), one including ground granulated blast furnace slag (GGBFS), and one incorporating both were tested. Preliminary results show that the inclusions of SLWA into a concrete mixture reduced shrinkage by 25% and overall tensile stress by 38%. / Master of Science

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