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Dynamic Interaction of Ground and Structure
  • Integrated Analysis System for Two-dimensional Finite Element Method
    FRONT for Windows
  • Two-dimensional Dynamic Soil-Structure Interaction Analysis
    SuperFLUSH/2D for Windows
  • Three-dimensional Dynamic Soil-Structure Interaction Analysis by the Substructure Method
  • Two-dimensional Nonlinear Soil-Structure Interaction Analysis by Effective Stress Method

NANSSI soil liquefaction analysis program

NANSSI is a program for analysis of two-dimensional nonlinear dynamic interactions using the effective stress method. It is intended for nonlinear dynamic soil-structure interaction problems that take into account variations in excess pore water pressure.


  • Program for analysis of nonlinear soil-structure interactions
  • Effective stress analysis based on Biot's theory of propagation in a saturated porous medium
  • Constitutive equation for soil (liquefaction model) using the Nishi model
  • Uses the Yin-Yang mixed method as the time integration method
  • Takes into account the semi-infiniteness of the ground by boundary processing of the model side surface and bottom surface
  • Analysis can take into account nonlinearity of both soil and structure

Application areas

  • Investigation of liquefaction of sandy soil
  • Analysis of nonlinear dynamic ground-pile-building interaction
  • Simulation of vibration tests
  • Nonlinear seismic response analysis of underground structures
  • Nonlinear response analysis of ground
  • Nonlinear vibration problems in other civil engineering and construction domains

Overview of features

Element types

Plane strain elements, beam elements, spring elements, joint elements

Constitutive law of plane strain elements

Modified Ramberg-Osgood model
Modified Hardin-Drnevich model
Nishi model
STATIC Duncan-Chang model
Cam-Clay model
Nishi-Esashi model
Nishi model

Restoring force characteristics of beam elements

General trilinear type, degrading trilinear type, retrograde type, origin-oriented type, maximum point-oriented type, bilinear slip type

Boundary conditions

Lateral viscous boundary, lateral superposition boundary, bottom viscous boundary

Disturbance conditions

  • Seismic motion input (vertically ascending waves, simultaneous horizontal and vertical input)
  • Node excitation input (forced loading)

Organization of programs

Name of program Features Remarks
NANSSI/1D One-dimensional nonlinear seismic response analysis Determination of liquefaction of stratified soil
NANSSI/2D One- and two-dimensional nonlinear seismic response analysis (seismic response and point excitation analysis) Determines liquefaction in a two-dimensional model, taking into account the nonlinearity of the structure
STATIC One- and two-dimensional nonlinear static analysis (excavation, backfill, and dead load analysis) Nonlinear analysis by the load incremental method, analysis of initial stress field
NAPOST1 Output of spatial distribution maps of deformation, stress, strain, etc. Supports NANSSI/2D and STATIC
NAPOST2 Output of time histories of acceleration, velocity, displacement, etc. Supports NANSSI/1D, NANSSI/2D, and STATIC
PROPERTY Assistance with setting material constants in nonlinear models Supports Nishi, Duncan-Chang, Cam-Clay, Nishi-Esashi, and other models

* NANSSI was developed jointly by Kozo Keikaku Engineering Inc. and Jishin Kogaku Kenkyusho, Inc.

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