Engineering Commons^™

Dynamic Vulnerability Assessment Of Highway And Railway Bridges, Mehdi Mohseni

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Dynamic loads can cause severe damage to bridges, and lead to malfunction of transportation networks. A comprehensive understanding of the nature of the dynamic loads and the structural response of bridges can prevent undesired failures while keeping the cost-safety balance. Dissimilar to the static behavior, the dynamic response of bridges depends on several structural parameters such as material properties, damping and mode shapes. Furthermore, dynamic load characteristics can significantly change the structural response. In most cases, complexity and involvement of numerous parameters require the designer to investigate the bridge response via a massive numerical study.

This dissertation targets three main …

Development Of System Reliability Models For Railway Bridges, Anna Maria Rakoczy

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Performance of the railway transportation network depends on the reliability of railway bridges, which can be affected by various forms of deterioration and extreme environmental conditions. More than half of the railway bridges in US were built before 1950 and many show signs of distress. There is a need for efficient methods to evaluate the safety reserve in the railway bridges by identification of the most sensitive parts of the bridge.

An accurate estimation of remaining fatigue life of a structural component is very important in prioritizing bridge rehabilitation and replacement. However, existing procedures to evaluate the fatigue behavior of …

Efficient Precast/Prestressed Floor System For Building Construction, Eliya Henin

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Precast floor systems provide a rapidly constructed solution to multi-story buildings that is economical, high quality, fire-resistant, and with excellent deflection and vibration characteristics. Conventional precast concrete floor system cannot compete with cast-in-place post tensioning flat slab floor systems when high span-to-depth ratio and flat soffit are required. This is due to the significant depth of standard precast beams, and use of column corbels and beam ledges. This research presents the development of a new precast concrete floor system that eliminates the limitations of conventional precast floor system and provides a competitive precast alternative to cast-in-place flat slab floor systems. …

Transversely Post-Tensioned Box-Beam System For Precast Parking Structures, Jenna Hansen

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Parking structures are essential to any growing commercial district, yet little thought is given to their longevity and appearance. This is particularly the case with precast parking structures. Typical issues include poor joint performance and the impact of stemmed members on interior building aesthetics. Research provided in this report proposes an alternate design that improves long term joint performance and optimizes the perspective spacing between deck members. These benefits (along with the others) are incorporated to reflect the benefits of parking structures designed using cast-in-place concrete and structural steel with concrete decking. Other benefits include: flexible column spacing, reduced / …

Safety Investigation And Guidance For Retrofitting Existing Approach Guardrail Transitions, Eric R. Jowza

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Throughout the United States, various approach guardrail transition systems are routinely implemented by State Highway Departments to connect standard strong-post, W-beam guardrail systems to the blunt end of concrete bridge rails and roadside median barriers. When installed correctly, approach guardrail transitions shield the hazardous exposed ends of rigid parapets as well as significantly reduce the propensity for wheel snag and vehicle pocketing throughout the transition region. Unfortunately, approach guardrail transitions that are installed in the field may not always resemble that of the as-tested configuration, thus reducing the desired lateral stiffness and strength of the transition system. A recent survey …