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Full-Text Articles in Engineering
Impact Of Extreme Summer Temperatures On Bridge Structures, Ryan Hagedorn
Impact Of Extreme Summer Temperatures On Bridge Structures, Ryan Hagedorn
Graduate Theses and Dissertations
Climate change and its effect on weather in the United States is a well-documented phenomenon. In particular, extreme heat waves have become more intense, more frequent, and longer lasting, especially in the southern United States. As with much of America’s transportation infrastructure, prestressed concrete bridge girders experience the effects of these heat waves. Uneven heating of optimized bridge girder sections results in large non-linear temperature gradients. In this study, temperature was monitored in three different AASHTO I-girders to determine the vertical and transverse temperature gradients in a pre-deck placement condition. It was determined that the current design standard, which uses …
Multiple Reference Impact Testing Of Bridges Using A Network Of Low-Cost Dynamic Exciters, James David Lindsey
Multiple Reference Impact Testing Of Bridges Using A Network Of Low-Cost Dynamic Exciters, James David Lindsey
Graduate Theses and Dissertations
Multiple Reference Impact Testing (MRIT) is a form of Experimental Modal Analysis (EMA) that can be used to identify the dynamic properties of full-scale bridges. These dynamic properties include natural frequencies, mode shapes, damping ratios, modal scaling and modal flexibility. Since these system properties that are directly related to the mass and stiffness characteristics of a structure, impact test measurements can be used to quantitatively characterize condition of a structure. Over time, changes in the properties can be monitored and evaluated as indicators of damage or deterioration. Instrumented hammers and drop masses are typically used to perform MRIT by providing …