When a single-track railway steel bridge has a span loaded length of 6 m in meters, what is the impact factor considered_________________?
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Answer: C. between 0.5 and 1.0
Explanation
Short span railway bridges experience high dynamic amplification from fast-moving locomotive loads. The dynamic impact factor for a six-meter span falls between zero point five and one point zero. Shorter loaded lengths require higher impact allowances due to rapid load application and vibration. Dynamic impact factors account for vibrations, track unevenness, and sudden wheel load surges. Design codes express impact factors as empirical formulas depending primarily on the effective bridge span. Railway engineering standards differentiate impact allowances based on single or multiple track configurations.
Bridge designers apply these impact multipliers to static live loads to ensure safe structural sizing. Accurate impact factor estimation prevents excessive fatigue cracking in steel railway bridge girders. Railroad authorities enforce strict load ratings to maintain safety across aging bridge inventories. An impact factor of zero ignores all dynamic train vibrations and moving load effects. A fixed value of zero point five underestimates the high dynamic amplification of very short spans. A maximum value of one point zero applies only to specific exceptional loading or detailing cases.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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