Experimental Study on Seismic Retrofitting Technology that Complements Existing Pile Foundations with Soil-Cement Columns made with Cementitious Solidification Material
By K. Tomisawa, T. Maki, T. Watanabe and T. Sasaya
Concrete Journal, Vol.51, No.6, Jun. 2013
- Synopsis
- Inadequate seismic performance of foundations during an earthquake causes excessive response displacement of the superstructure, which may degrade the functions of the entire structure. Thus, like the seismic reinforcement of superstructures and substructures, reinforcement measures are considered necessary for the existing foundations of structures that could not be provided with the required seismic performance, including liquefaction countermeasures. Consequently, as a reasonable seismic retrofitting technology for foundations in soft ground or liquefied ground, composite piles that provide soil-cement columns made with cementitious solidification material around pile foundations were researched and developed. Composite piles differ from conventional foundation seismic reinforcement methods that integrate reinforcement piles, reinforcement material or soil-cement columns with the substructure in that they represent a technology that aims to secure seismic performance of existing pile foundations solely through the reaction force of soil densification columns, and they are considered advantageous in terms of executability and cost. A series of large-scale experiments on the practical application of composite piles was conducted and findings on their seismic performance centering on the energy absorption effect are reported.
- Keywords:
- pile foundations, soil-improvement, seismic retrofitting, loading test, shear box
