- 上一篇：建筑热舒适性英文文献和中文翻译
- 下一篇：钢筋在混凝土中的受压英文文献和中文翻译
conventional design loads. Consequently, highway bridges designed using current design codes may suffer severe damages even from a relatively small size explosion. Although several guidelines for the design of blast resistant buildings exist, e.g., U.S. Department of the Army (USDOA) (Baker et al. 1992), U.S. Department of Defense (USDOD) (2002, 2008), Defense Threat Reduction Agency (DTRA) (1997), U.S. General Services Administration (GSA) [2003; Interagency Security Committee (ISC) 2001], National Institute of Standards and Technology (Ellingwood et al. 2007), andASCE (2010), there is very limited information available on analysis, design, and detailing of bridge components subject to blast loads. Themost detailed literature in this area is the National Cooperative Highway ResearchProgram (NCHRP) 645 report titled “Blast-ResistantHighway Bridges: Design and Detailing Guidelines” (Williamson et al. 2010), which presents some simplified design guidelines against blast loads.However, this guideline also does not provide much information on failure modes of different bridge components during blast loads.
Williamson et al. (2011a, b) have investigated the response of reinforced concrete bridge columns subjected to blast loads and have recommended three separate blast design categories using the scaled standoff distance as the primary variable to assess threat severity. Fujikura and Bruneau (2011) have tested a scaled model of a multicolumn pier bent with concrete-filled steel tube (CFST) columns to blast loads. Test results show that the seismically designed RC and steel jacketed RC columns did not exhibit ductile behavior under blast loading and failed in shear at their base rather than flexural yielding. Son and Astaneh-Asl (2009) have investigated blast load
effects on orthotropic deck trusses used commonly in cable-stayed and suspension bridges through finite-element simulation. This study shows that (1) decks with mild steel perform better under blast load than those with high-strength steel; (2) traditional suspension bridges, where the main cables are anchored to the anchor blocks in the ground, perform extremely well when subjected to blast loads on the deck; and (3) self-anchored suspension bridges, where the main cables are anchored to the bridge deck rather than the anchor blocks, performed poorly and underwent global P-D instability and progressive collapse. Ray et al. (2003) have compared the prediction of blast loads under a bridge overpass with low-, medium-, and highresolution finite-element models, and have discussed the effects of factors, such as charge shape and clearing distance on blast load prediction. Baylot et al. (2003) have presented a prediction method for the response of steel bridge beams and girders to blast and fragment loads by developing a load measure, a single number that can be easily computed for any combination of fragment and blast loads. If the load measure is exceeded for a given combination of blast and fragment loads, then beam failure is predicted. Ray (2006) has carried out analytical studies and large-scale experimental blast tests on steel bridge towers subjected to blast loads.
Marchand et al. (2004) has addressed the effect of blast loads on highway bridge superstructures in a preliminary study for a two-span bridge model subject to underdeck blasts. Their investigation shows that breaching failure of the concrete governs in cases of large truck bombs with limited standoff or counterforce charges. Williamson and Winget (2005) and Winget et al. (2005) have presented some analysis results and design recommendations for bridges under blast load based on the analysis of a single degree of freedom (SDOF) system. Based on best practices obtained from an international literature review, they have discussed the incorporation of physical security and site layout principles into the design process and have recommended structural design and retrofit solutions to counter potential effects of blast loads on bridges. Anwarul Islam and Yazdani (2008) showed that typical AASHTO girder bridges are unable to resist probable blast loads. Ghali and Tadros (1997) have investigated the progressive collapse of highway bridges, which can result because of the loss of a local bridge component during a blast event, for a 12,910-m-long bridge on Northumberland Strait in Canada. They proposed a modified design where a drop-in span will just separate from the rest of the bridge during local damage to the bridge deck, leaving the remaining bridge system vibrating freely due to dynamic loads created during the local damage.