Pedestrian bridges have evolved from merely functional to works of art that often integrate with a city’s design plan. With improved appearance come more complex structural design elements and construction challenges. Ensuring bridge integrity and pedestrian safety becomes more significant with more complicated fabrication. Surprisingly, pedestrian bridges have no standard in-service inspection criteria, often leaving inspectors to resort to implementing highway bridge standards. Monitored by the National Bridge Inspection Standards, highway bridges go through two inspection stages prior to opening, allowing for corrective action at a lower cost, followed by regular inspections once in service to ensure continued performance. Pedestrian bridges without a formal inspection process default to a calendar-based approach, typically every 24 months. This time-based solution does not account for design characteristics or environmental impacts that could benefit from more frequent reviews. And following highway bridge standards does not account for pedestrian-specific safety issues, like conditions of surfaces, railings, or vibration.
In “Proposed Criteria for the In-Service Inspection of Pedestrian Bridges,” a new study for the Journal of Bridge Engineering, authors Aedh Alharthi and Robert Connor used a risk-based inspection method to determine optimal inspection intervals for pedestrian bridges. This method associates the inspection interval with the risk associated with each bridge; the higher the risk the shorter the interval. Learn more about this study, their survey of current pedestrian bridge management practices, and the unique safety and serviceability criteria they incorporated at https://doi.org/10.1061/JBENF2.BEENG-7055. The abstract is below.
Abstract
In recent years, the design and construction of pedestrian bridges have gone beyond those that simply provide a safe passage for pedestrians to cross obstacles. These structures are often designed to be iconic works of art that are integrated into the overall design plan of the city. However, the pleasant appearance of these bridges often results in designs requiring very complex structural systems, unique fabrication requirements, and significant construction challenges. While in-service inspection is a crucial part of ensuring the safe and reliable functionality of all bridges during their service life, there are no specific uniform national criteria for in-service inspections applicable to pedestrian bridges in the United States nor specific training requirements for such inspectors. In contrast, federal law governs the intervals, scope, and inspector training requirements for highway bridges. Mapping the existing strategies for inspection used for highway bridges directly, however, may not be the best approach. Therefore, research was conducted to develop proposed in-service inspection criteria specifically developed for pedestrian bridges to improve their safety and long-term serviceability. A risk-based inspection approach was adopted to estimate suitable inspection intervals and scope for various types of pedestrian bridges. Additionally, the assessment of safety and serviceability criteria unique to pedestrian bridges is also discussed. Implementing the proposed inspection criteria should increase the safety and serviceability of pedestrian bridges and allow for better utilization of limited inspection resources.
See how these new criteria specific to pedestrian bridges can enhance inspections, improve maintenance and thereby public safety in the ASCE Library: https://doi.org/10.1061/JBENF2.BEENG-7055.
