Two major earthquakes in Alaska, namely the 1964 Great Alaska Earthquake and the 2002 Denali Earthquake, occurred in winter seasons when the ground crust was frozen. None of the then-existing foundation types was able...Two major earthquakes in Alaska, namely the 1964 Great Alaska Earthquake and the 2002 Denali Earthquake, occurred in winter seasons when the ground crust was frozen. None of the then-existing foundation types was able to withstand the force from the lateral spreading of frozen crust. This paper presents results from the analysis of pile foundations in frozen ground overlying lique- fiable soil utilizing the Beam-on-Nonlinear-Winlder-Foundation （BNWF） （or p-y approach）. P-multipliers were applied on tradi- tional sandy soil p-y curves to simulate soil strength degradation during liquefaction. Frozen soil p-y curves were constructed based on a model proposed in a recent study and the frozen soil mechanical properties obtained from testing of naturally frozen soils. Pile response results from the p-y approach were presented along with those from fluid-solid coupled Finite Element （FE） modeling for comparison purpose. Finally, the sensitivity of pile response to frozen soil parameters was investigated and a brief discussion is presented.展开更多
Generally, the number of fatigue cycles, the range of the repeated stresses, and the type of the structural details are the key factors affecting fatigue in large-scale welded structures. Seven types of struc- ture ...Generally, the number of fatigue cycles, the range of the repeated stresses, and the type of the structural details are the key factors affecting fatigue in large-scale welded structures. Seven types of struc- ture details were tested using a 2000-kN hydraulic-pressure-servo fatigue machine to imitate fatigue behav- ior in modern steel-truss-structures fabricated using thicker welded steel plates and integral joint technology. The details included longitudinal edge welds, welded attachment affecting detail, integral joint, and weld re- pairs on plate edges. The fatigue damage locations show that the stress (normal or shear), the shape, and the location of the weld start and end points are three major factors reducing the fatigue strength. The test results can be used for similar large structures.展开更多
基金funding from Alaska University Transportation Center (AUTC)the State of Alaska Department of Transportation and Public Facilities (ADOT&PF) under projects AUTC Projects #309011 and #510021
文摘Two major earthquakes in Alaska, namely the 1964 Great Alaska Earthquake and the 2002 Denali Earthquake, occurred in winter seasons when the ground crust was frozen. None of the then-existing foundation types was able to withstand the force from the lateral spreading of frozen crust. This paper presents results from the analysis of pile foundations in frozen ground overlying lique- fiable soil utilizing the Beam-on-Nonlinear-Winlder-Foundation （BNWF） （or p-y approach）. P-multipliers were applied on tradi- tional sandy soil p-y curves to simulate soil strength degradation during liquefaction. Frozen soil p-y curves were constructed based on a model proposed in a recent study and the frozen soil mechanical properties obtained from testing of naturally frozen soils. Pile response results from the p-y approach were presented along with those from fluid-solid coupled Finite Element （FE） modeling for comparison purpose. Finally, the sensitivity of pile response to frozen soil parameters was investigated and a brief discussion is presented.
基金Supported by the Science and Technology Development Project of the Ministry of Railways China (No. 96G35)
文摘Generally, the number of fatigue cycles, the range of the repeated stresses, and the type of the structural details are the key factors affecting fatigue in large-scale welded structures. Seven types of struc- ture details were tested using a 2000-kN hydraulic-pressure-servo fatigue machine to imitate fatigue behav- ior in modern steel-truss-structures fabricated using thicker welded steel plates and integral joint technology. The details included longitudinal edge welds, welded attachment affecting detail, integral joint, and weld re- pairs on plate edges. The fatigue damage locations show that the stress (normal or shear), the shape, and the location of the weld start and end points are three major factors reducing the fatigue strength. The test results can be used for similar large structures.
