Response Modification Factor of Piles Installed in Permafrost Soil

• Main Author: Mracek, Jack Jr.
• Other Authors: Salem, Yasser, Department of Civil Engineering, Cho, Jin
• Format: Other/Unknown Material
• Language: English
• Published: California State Polytechnic University, Pomona 2019
• Subjects: permafrost; FEA; finite element analysis; response modification factor; Winkler model; incremental dynamic analysis; trans Alaska pipeline; pipe support; SolidWorks simulation; non-linear link element; Alaska
• Online Access: http://hdl.handle.net/10211.3/213397

The Trans-Alaska Pipeline is about 800 miles long with 420 miles of it elevated by about 78,000 support assemblies. These piles were installed into bored holes and then cemented in place with a slurry of water and sand. Once the slurry is frozen, the pile is essentially fixed into place. This project attempts to create a Response Modification Factor that will provide seismic design data for a range of piles installed in this permafrost. Because field testing of real piles is impractical at this stage, Finite Element Analysis will be used to determine the piles response to earthquakes. Part A of the project used SolidWorks Simulation to create a 3D model of the pile and its surrounding soil layers. This pile was then loaded with a cyclic loading pattern up to its yield point. The time history displacements and forces where then collected for each layer of the soil and used to generate the non-linear spring coefficients for Part B of the project. Part B of the project will use SAP2000 to model an equivalent cantilever model of the pile and soil. The non-linear spring coefficients will be used from Part A of the project to setup the soil pile interface. An Incremental Dynamic Analysis will then be performed to obtain the structures response to 22 earthquakes. A response modification factor will then be calculated for each case study. The analysis procedures and a discussion of the results for Part A are presented here in this report. Another student will perform the Part B of the project at a later date. The two parts will then be combined at that time.