Seasonally Frozen Soil Effects on the Nonlinear Behavior of a Parking Garage

This paper presents the results of experimental and analytical studies of the seasonally frozen soil effects on a three-story reinforced-concrete parking garage. With a 16-channel portable accelerograph, vibration test data were collected during the winter of 2006–2007. The structural dynamic properties were identified from the recorded data. Meanwhile, a three-dimensional Finite Element (FE) model including both superstructure and soil has been developed in order to verify the frozen soil effects. The FE modeling results indicate that the fundamental frequency of the soil-structure system increases 50% as the frost penetrates from 0 to 1.4 m. It is found by push-over analysis that the system stiffness increases 114% due to soil freezing. Most importantly, the shear distribution between columns and shear walls is significantly changed due to soil freezing. When soil thaws, the shear force taken by columns increases 10∼15%, and that taken by shear walls decreases by 10∼15%. It also shows that more columns experience yielding at thawing condition. This indicates that crucial zones in the frame-shear wall structures might move from shear walls to columns.