Title: Innovative Retrofit of a Steam Turbine Generator Foundation to Mitigate Settlement
Author(s): Hongchun Liu, Jaspal S. Saini, Gang Zhao, Sushil Chauhan, Namgyu Park, Mahi Galagoda, Steven Wu
Publication: Symposium Paper
Appears on pages(s): 19-34
Keywords: steam turbine generator foundation, foundation retrofit, foundation settlement, piles, dynamic analysis, frequency-dependent dynamic impedances, soil impedances, pile impedances.
This paper discusses an innovative retrofit that stabilized a Steam Turbine Generator (STG) pedestal
foundation undergoing unexpected differential settlements during construction. The innovative solution involved
driving steel H-piles around the STG foundation perimeter. A new concrete bracket (a.k.a. corbel) was added around
the STG foundation perimeter to fully engage and integrate the H-piles with the existing pedestal foundation. The pile
layout was established and optimized based on dynamic and static performance analyses of the modified foundation
geometry using finite element (FE) software ANSYS, considering bounding pile and soil dynamic impedances. The
frequency-dependent dynamic pile impedances were calculated using DYNA6. The continuous settlement monitoring
of the STG foundation demonstrated that the retrofit effectively seized the ongoing settlements and stabilized the
foundation enabling the subsequent machine installation.