Seismic,environmental vibration

Illustration of vibration propagation in soil

 NSC has an extensive track record in the seismic analysis of civil engineering structures. In addition to earthquake resistance diagnosis, our experience includes earthquake hazard analysis, determination of anticipated earthquake ground motion, proposal of seismic reinforcement measures, and execution design. We also have a great deal of experience in environmental vibration analysis.

1. Earthquake environment investigation and ground motion studies

Example of determining earthquake ground motion
based on the probabilistic approach

 There are two approaches for determining the input earthquake ground motion on a structure: the probabilistic approach to earthquake occurrence phenomena, and the approach of directly calculating the earthquake ground motion based on assumptions regarding active faults where earthquakes could occur. We have experience in the use of both approaches to determine earthquake ground motion.

2. Earthquake resistance diagnosis and analysis of above-ground and underground structures

Vibration testing of underground structures

 We have performed earthquake resistance diagnoses for both above-ground and underground structures. With regard to the latter, our capabilities include coupled analysis of structures and soil, determination of complex behavior by testing and other methods as needed, and the implementation of diagnostic and design services with a high level of safety in relation to underground structures that are continuous with superstructures or located next to other structures, in addition to the analysis of ordinary underground structures.

3. Earthquake resistance diagnosis and analysis of soil structures

 We provide analyses based on two-dimensional and three-dimensional finite element methods with regard to earthquake deformation in revetments, embankments, and the like. We have an extensive track record in liquefaction analysis using LIQCA and FLIP, which are typical effective stress analysis codes.

Example of revetment analysis: Deformation )

Example of revetment analysis: Distribution of excess pore pressure )

Please refer to the following for more detailed information.

  • ・Aseismic design of caisson revetments using liquefaction analysis programs
  • ・Basic design based on predictive analysis of lateral flow due to liquefaction (using LIQCA for dynamic deformation analysis)
  • ・Analytical study of seismic reinforcement methods for bridge abutments in liquefied soil
  • ・Analytical study of seismic reinforcement methods for embankments in liquefied soil

4. Environmental vibration analysis

Vibration testing using a vibration generator

We can analyze the propagation of mechanical vibrations and traffic vibrations to the surrounding area and the effects of vibration isolation works. We offer comprehensive study services, ranging from the measurement of existing vibrations to proposing countermeasures and performing measurements to confirm the effects of countermeasures.

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