LATWAK: IMPACT TEST TO OBTAIN PILE LATERAL STATIC STIFFNESS

To conduct a LATWAK test, a horizontal velocity transducer is attached to pile and then the pile is struck on the side in the horizontal direction. The blow is delivered with a sledge hammer instrumented with a dynamic force transducer. Data recorded at the time of impact are the force time signal from the hammer (input) and the velocity time signal from the pile (output). The experimental mobility curve is obtained as a function of frequency by computing the modulus of the complex valued ratio of velocity over force using Discrete Fourier Transforms. Theoretically, the pile is an elastic member with mass and the soil is modeled by linear springs and viscous damping. The problem of the steady state forced vibration of the pile in such a soil is determined mathematically. It leads to the theoretical mobility curve for the pile-soil system. The experimental mobility curve obtained in the LATRWAK test on the pile is matched with the theoretical mobility curve. A system identification method is used to match the two curves and to extract the best-fit model parameters, which include the static lateral stiffness K for the pile-soil assembly. To assess the usefulness of the technique, the lateral stiffness Kp predicted by the LATWAK test on a pile was compared to the lateral stiffness Km measured in a static lateral load test on the same pile. A total of 20 pile load tests and 20 LATWAK tests were conducted and used to compare Kp and Km.

Language

  • English

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: p. 437-444
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00726083
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 21 1996 12:00AM