GEODesign was retained to perform seismic analyses of the bridge approach foundations for the purpose of providing foundation stiffness parameters for use by the structural engineer in their analysis of the existing and retrofitted structure. Various techniques were used to strengthen the arch blocks, including in-filling portions of the arch blocks with concrete, improving the soil by jet grouting, and installing micropiles in selected areas.
The Solutions Unearthed
- We developed soil profiles and parameters based on existing subsurface information and reviewed existing drawings to estimate foundation sizes.
- We developed a complex 2D model to develop longitudinal and transverse stiffness values for lateral, vertical, and rotational movements.
- We performed analyses for both “untreated” and “treated” soils, to show the effect of the strength increase on the stiffness values.
- We estimated bearing capacities for the improved arch block foundations.
- We developed updated site-specific design response spectrum for the Brooklyn approaches.
Client: Parsons Corporation