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Stoyanoff, Stoyan; Taylor, Zachary; Dallaire, Pierre-Olivier; Larose, Guy
2023 Bridge Structures
doi: 10.3233/brs-230210
Wind stability and design loads of long-span bridges are assessed applying experimental and theoretical methods. The commonly used approach entails the extraction of fundamental aerodynamic data of key structural elements such as the deck, towers, and cables, either experimentally or numerically, and the application of theoretical models for evaluation of structural responses to turbulent winds. This phenomenon called buffeting is extremely complex and, to date, there is no closed-form theoretical model to reproduce how the wind converts to structural responses and loads which the bridge must resist. The objective of this paper is to explore the base of the problem, namely the transformation of wind gusts to actual loads, and the response estimations. The time domain response approach has been adopted for solution of the generalized equations of motion allowing the exploration of details in the performance of various theoretical interpretations. Starting from the classic quasi-static linear model, theoretical simplifications are removed toward a more complete model of buffeting loads. Non-linear and aerodynamic coupling effects on response predictions are examined specifically aiming at improved buffeting load representations within the framework of the currently available experimental data. A new concept called stack state-space analysis has been introduced for the response solution to wind buffeting. Aerodynamic and structural data of Pierre-Laporte Bridge in Québec City, and the IABSE Working Group 10, long-span bridge validation example, are utilized as representative cases in this study. Avenues for further experimental and numerical validations of the presented new solution approach are suggested toward more accurate predictions of wind response and design loads of long-span bridges.
Miyachi, Kazuhiro; Saimoto, Shoya; Oki, Yusuke
2023 Bridge Structures
doi: 10.3233/brs-230214
This study investigated the relationship between “rust color distribution ratio,” “corrosion surface shape,” and “fatigue strength” of high-strength galvanized steel wires used in cable supported bridges. The study utilized a digital image color analysis system to classify the rust color distribution rate and categorize corrosion levels based on the distribution ratio. The relationship between cross-sectional loss rate and corrosion depth tendency was visually and quantitatively comprehended from the categorized corrosion levels. The study found that fatigue and tensile strengths of the specimens from the corrosion levels set in this study were equivalent to or higher than those of new wires. However, the possibility of variations due to the small number of specimens or insufficient corrosion progress cannot be ruled out.
Fedorova, Maria; Sivaselvan, M.V.; Kurc, Ozgur; Karakaplan, Ali
2023 Bridge Structures
doi: 10.3233/brs-230213
Rail-structure interaction (RSI) analysis and vehicle-track-structure-interaction (VTSI) analysis are often required during bridge design. For example, the California High-Speed Train Project requires RSI analysis for final design of all structures, as well as VTSI analysis, with the level of interaction to be modeled determined by the complexity of a structure. The goal of RSI analysis is to ensure that superstructure deformations and rail stresses are within acceptable limits. VTSI analysis is a dynamic analysis that takes into account influence of actual trainsets. VTSI Level 1 analysis includes train loads as a series of moving loads. This analysis allows evaluation of dynamic impact effects from trainsets and vertical accelerations of the deck. For complex high-speed railway bridges, VTSI Level 2 might be required, accounting for full dynamic interaction between the trainset and the bridge. To represent this interaction, the trainset is modeled as a multibody system consisting of rigid bodies, springs, and dashpots. The interaction between wheels and rails is accounted for through kinematic constraints and Lagrange multipliers. This paper presents modeling, RSI, and VTSI analyses of a railway bridge in the LARSA 4D software package. The track and superstructure are modeled in an expedited way using a macro that generates the track, approach, and bridge geometries. Fasteners are modeled as hysteretic springs and automatically positioned along the curved geometry of the track using a LARSA 4D’s bridge path coordinate system definition. RSI analysis is performed accounting for temperature differentials between rails and the deck, vertical train loads, acceleration and braking forces. Break in the rail is introduced using stage construction analysis, followed by progressive collapse analysis (with adapting increments and arc-length control) or nonlinear dynamic analysis. Finally, VTSI Level 1 and 2 analyses are performed and the results are compared. Car body accelerations are compared to limit values to ensure passenger comfort.
Kozy, Brian; Beckstrom, Jonathan; Armbrecht, Tim; ,
2023 Bridge Structures
doi: 10.3233/brs-230212
Over time, owners may face challenges with management of bridges with outdated details. One such detail that is no longer used today is the steel girder shiplap connection. These were originally employed to simplify analysis of continuous girders while also moving joints away from the piers, improving longevity of bridge bearings and substructures. Unfortunately, fatigue issues have appeared in these connections resulting in cracking at critical load-carrying locations. In this project, analysis was performed to investigate connection fatigue and strength and retrofit design verification. Results utilizing non-linear analysis showed that while stresses from ultimate loading could adequately redistribute throughout the web, high stress concentrations were created, exacerbating fatigue. Stress calculations for shiplap web details are not well codified or easily assessed with simple hand calculations, so finite element analysis was utilized. Results showed web fatigue life had been exhausted with more cracking expected at other locations, convincing the owner retrofit was necessary even though the bridge was programmed for replacement.
Acosta, Kevin; Tjepkema, Daan; de Meijier, Felix
2023 Bridge Structures
doi: 10.3233/brs-230211
Part of the Netherlands’ busiest highway, the Van Brienenoord Bridge comprises 12 lanes of traffic split across the eastbound bridge built in the 1960 s and the western bridge built in the 1990 s. The Van Brienenoord Bridge complex consisting of two parallel 300 m span steel arch bridges, approach structures and three parallel bascule bridges over the New Meuse. The bridges carry about 230,000 vehicles daily. A strengthening and replacement strategy was developed to reduce road closures to one of the two bridges at a time and reducing this time to weeks instead of months. The strengthening consists of plate stiffeners to the main girders and arches and a new deck. Construction begins in 2025 and will extend the bridge’s useful life to another 100 years. The strengthening instead of replacing is in line with RWS’ commitment to adopting circular economy principles for their infrastructure network.