Comprehensive Seismic Response Analysis for Estimating the Seismic Behavior of Buried Pipelines Enhanced by Three-Dimensional Dynamic Finite Element Analysis of Ground Motion and Soil Amplification

Abstract

We demonstrate a comprehensive earthquake response analysis method for improving the seismic input force estimation of buried pipelines by combining ground motion and soil amplification analyses. Using this method, the seismic input force of an actual pipeline was estimated and its seismic performance was checked for a largest assumed seismic fault scenario. Three-dimensional inhomogeneity of ground and surface topography is known to greatly affect the results of ground motion and soil amplification analyses. To consider these effects, a linear wave propagation analysis using a 10 × 109 degree-of-freedom three-dimensional finite element model was conducted for the ground motion analysis, and a nonlinear wave propagation analysis using an 80 × 106 degree-of-freedom three-dimensional finite element model was conducted for the soil amplification analysis. The application example showed that three-dimensional inhomogeneity of ground and surface topology caused complex seismic input forces to buried pipelines, and demonstrated the effectiveness of the comprehensive seismic analysis method proposed in this study.

Development of Three-Dimensional Soil-Amplification Analysis Method for Screening for Seismic Damage to Buried Water-Distribution Pipeline Networks

“…Following previous studies [13,14], we used a solid 3D finite-element method that can model complex ground geometry appropriately while satisfying the traction free surface boundary condition analytically. Modeling ground shaking as a wave propagating in a nonlinear material and discretizing in the temporal domain using the Newmark-β method (β = 1/4, δ = 1/2) leads to the following:…”

“…In previous studies, 3D soil amplification analyses were applied to sites with single high-pressure gas pipelines [13,14]. Although such main gas pipelines are usually placed in sites that have relatively good seismic characteristics, some parts of an entire water-distribution pipeline network could be located where there are distinct changes in the ground properties.…”

“…With the improvement in sensor technology, computational methods, and computer technology, ground data information accuracy and resolution has improved, and physics-based simulation based on such data is becoming feasible. In addition to physics-based earthquake wave propagation simulations targeting wave propagation from source to sites (e.g., [10][11][12]), methods have been developed recently to estimate local soil amplification by analyzing dynamic nonlinear 3D ground motion [13,14]. In these methods, a ground model consisting of ground layers is generated from boring logs, and soil amplification is estimated by inputting acceleration waveforms into high-resolution 3D analyses.…”