Rethinking bridge design: Overdesign as a key to centuries scale lifespan
Moving Toward Smart, Resilient and Sustainable Bridges, CRC Press, ss.3317-3323, 2026
- Yayın Türü: Kitapta Bölüm / Araştırma Kitabı
- Basım Tarihi: 2026
- Doi Numarası: 10.1201/9781003778677-402
- Yayınevi: CRC Press
- Sayfa Sayıları: ss.3317-3323
- Orta Doğu Teknik Üniversitesi Adresli: Evet
Özet
Most highway bridges built in the second half of the 20th century are now beyond their intended service life, and national inventories consistently show a substantial portion performing below desired safety levels. FHWA reports indicate that approximately 7–10% of U.S. bridges are structurally deficient (SD), while GAO analyses based on broader criteria report about 10% SD and 14% functionally obsolete (FO). Even with frequent inspections, load restrictions, and targeted strengthening measures, several sudden collapses; such as the I-35W truss bridge failure in Minneapolis (2007), the Fern Hollow bridge collapse in Pittsburgh (2022), and the Nanfang’ao steel-arch collapse in Taiwan (2019) demonstrate that aging and deterioration continue to pose major threats to life and property safety. Historic stone and masonry bridges, in contrast, often remain serviceable for centuries. A common characteristic among these long-lasting structures is that they were built with significantly higher reserve capacity than strictly required. A focused literature review (e.g., studies on century-scale performance of stone arch bridges, design-life evaluations of old steel bridges, and data-driven bridge lifetime estimates) indicates that higher inherent safety margins correlate with longer service life, slower deterioration, and reduced maintenance demand. This study investigates whether overdesign can be formulated as a rational optimization strategy for modern highway bridges. The concept evaluates the balance between increased initial construction cost and the resulting gains in structural longevity, reduced maintenance cycles, resilience to uncertainty, and overall system reliability. Preliminary considerations suggest that moderate increases in reserve strength may yield disproportionately large extensions in effective service life, potentially approaching multi-century performance for certain bridge types. The proposed framework aims to initiate a broader discussion on cost-effective, long-lifespan bridge design and ultimately support long-term public safety and economy.