Performance and Repair Design of Stay Cables with Rain/Wind-Induced Vibrations

The results of a multifaceted investigation into large-amplitude vibrations of bridge stay cables are presented. The vibration of the stay cables occurred under light rain and wind conditions, and resulted in low-frequency, large-amplitude oscillations having recorded displacements of over 24?in. (0.6?m). Due to concerns about the implications of the vibrations on the integrity and durability of the stay cables and observed damage to stay-cable anchorage components, an investigation and repair program was developed. The final repair program arose from an investigation that combined the talents of practicing engineers, the Texas Department of Transportation, and representatives from four universities. Ultimately, a combination of supplemental hydraulic dampers and cable restrainers were used to mitigate the vibrations. This paper describes the results of the investigation and presents the practice-based methodology used to develop the implemented repair program.     

Rapid Bridge Replacement: Processes, Techniques, and Needs for Improvements

The terrorist attack on September 11, 2001 and subsequent potential threats to the United States transportation systems have presented an urgent need to develop emergency response plans in order to quickly react to the possible consequences of an extreme event. Highway bridges, as critical components of the nation’s transportation network, have received increased attention. To respond to the potential threats on highway bridges, a research project was conducted to identify rapid bridge replacement processes, techniques, and needs for improvements. To achieve the research objectives, the research team studied three cases of previous bridge replacements following extreme events. By studying these cases, the research team first sought to identify and expand on lessons learned and then addressed which actions did and did not work effectively under the incident circumstances. Using the lessons learned government agencies and engineering and construction communities could enhance their emergency response plans for future incidents. Next, the research team identified needed improvements so that the research community could investigate new technologies to advance current practices.     

Evaluation of the Design, Planning, Construction Phases, and Structural Content of Permanent Residential Dwellings Built after the 1999 Eastern Marmara Earthquakes in Turkey

The aim of this study is to survey and evaluate permanent housing structures built after the Marmara earthquakes based on the principles of earthquake resistant design of reinforced concrete structures. The seismicity of Turkey requires immediate attention as there is a high probability of another major earthquake event in the next 30?years in Istanbul. The classification of structural systems, the damage patterns and behaviors of structural systems, and structural and nonstructural components under lateral earthquake loads, are analyzed. Based on this analysis, reliable structures can be built without overextending the Turkish economy, and loss of life and structural damage can be reduced by designing structures with greater earthquake energy dissipation capacity. The selection of project areas and the strength of the structural system are thoroughly analyzed taking postearthquake public psychology into account. Structural characteristics of permanent housing built subsequent to the Marmara earthquakes are critiqued and documented with a case study.