08-01-2011, 07:42 PM
Near-Fault Seismic Ground Motions
Author: Dreger, Douglas S., Hurtado, Gabriel, Chopra, Anil K., Larsen, Shawn C. | Size: 3.9 MB | Format: PDF
Bridges that cross faults are subject to static deformation that occurs at almost the same time as the arrival of dynamic pulse-like ground motions. Static offsets can be as large as several centimeters to many meters and strong ground motion velocity pulses exceeding 100 cm/s have been observed. Near-fault records, in the distance range of 10 to 100s of meters from faults are essentially nonexistent except for a few cases and therefore numerical simulation of ground motions for such near-fault situations is necessary. The paper presents simulated ground motions to 17.5 Hz, 15-100m from the fault for a Mw6.5 earthquake using an elastic finite-difference code. Simulations for homogeneous earth structure are compared for uniform and heterogeneous fault rupture scenarios. To investigate asymmetry of ground motions on opposite sides of a dipping reverse fault the dislocation method of Okada (1992) is used to compute static offset. From those results a simplified procedure for the simulation of near-fault time histories is developed. All of the simulations assume linear elasticity, and it is noted that the computed strain is as high as 10-4 - 10-3, and it is likely that there would be significant non-linear behavior in this near-fault region.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
http://forum.civilea.com/thread-27464.html
***************************************