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Prestressed continuous rigid-frame bridges, a prevalent structural system in large-span bridge construction, present unique demolition challenges due to spatial constraints and adjacent infrastructure constraints during demolition. This study examined the controlled demolition of a river-crossing, prestressed, continuous, rigid-frame bridge using a blasting demolition practice. The demolition strategy incorporated mechanical crushing of mid-span deck and wing plates, complemented by strategically positioned blasting cuts at critical structural elements, including piers, mid-span box girder webs, top slabs, external prestressed steel cable anchor piers, and bridge-end box girder connections. The implementation of a sequential detonation order (mid-span box girders followed by external prestressed cable anchor piers, concluding with bridge-end connections and piers) resulted in controlled segmental collapse. Numerical simulation using LS-DYNA's dynamic finite element analysis validated the demolition scheme, revealing key process parameters: a total collapse duration of 4.5 seconds and a deck impact velocity of 13.6 m/s. The analysis identified impact stress as the primary mechanism for structural disintegration. A significant finding emerged regarding external prestressing technology. While originally implemented to enhance service performance and load-bearing capacity, the release of prestressing forces through controlled blasting was found to improve structural fragmentation efficiency significantly. Field implementation demonstrated the technical feasibility and safety of this approach, providing an effective solution for dismantling long-span, prestressed, continuous, rigid-frame bridges in complex environments. The study establishes a comprehensive framework for similar demolition projects, highlighting the importance of integrated mechanical and explosive techniques in modern bridge demolition engineering.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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