Geotechnical Engineering Circular No. 9 Design, Analysis, and Testing of Laterally Loaded Deep Foundations that Support Transportation Facilities
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Soldier Rev B
| 8.4.2 Vehicular Collision Loads AASHTO (2014) requires that bridge abutments and piers located 30 feet from the edge of roadway be investigated for vehicle collision loads. Collision loads maybe addressed by either providing crash protection or by providing structural resistance to the load. Crash protection maybe provided by an embankment, or a structurally independent crash-worthy ground mounted barrier. Refer to AASHTO (2014) for additional requirements for crash protection barriers, including height and offset distance requirements, loading conditions, annual frequency of impact, etc. For cases where the vehicular crash loads are resisted through structural resistance, the crash load is modeled as an equivalent static force of 600 kips acting at a direction of zero to 15 degrees with the edge of pavement in a horizontal plane at a distance of 5 feet above the ground. This load is based on full scale crash tests using tractor trailers. For individual columns, the load should be considered as a point load. For wall piers or abutments, the load maybe distributed over a suitable area, but the area should be no larger than 5 feet wide by 2 feet high (AASHTO 2014). The requirements outlined above are for bridges impacted by trucks. Other vehicular impacts, such as trains, should be addressed on a case by case basis and in accordance with applicable codes or design standards, such as the AREMA Manual for Railway Engineering or local transit agency guidelines. As indicated above, the vehicle collision force (CT) is applied as a load to the structure. A structural analysis is required to resolve the force effects of the collision force to reactions at the head of the foundations elements. Once the applied loads at the top of the foundation elements are determined, a lateral load analysis is performed as previously described. Because the CT load is applied as an equivalent static load, there are no additional special considerations in the foundation analysis i.e., no dynamic or cyclical load considerations. Download 6.03 Mb. Share with your friends:
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