Numerical Study of the Seismic Response of an Instrumented Building with Underground Stories

Abstract

Engineering practitioners do not usually include soil–structure interactions in building design; rather, it is common to model and design foundations as embedded joints with joint–based reactions. In some cases, foundation structures are modeled as rigid bodies, embedding the first story into lower vertical elements. Given that the effects of underground floors on the seismic response are not generally included in current building design provisions, it has been little explored in the literature. This work compares and analyzes models to study the effects of different underground stories modeling approaches using earthquake vibration data recorded for the 16–story Alcazar building office in downtown Viña del Mar (Chile). The modeling expands beyond an embedded first story structure to soil with equivalent springs, representing soil–structure interaction (SSI), with varying rigid soil homogeneity. The building was modeled in a finite element software considering only dead load as a static load case because the structure remained in the framing stage when the monitoring system was operating. The instruments registered 72 aftershocks from the 2010 Maule Earthquake, and this study focused on 11 aftershocks of different hypocenters and magnitudes to collect representative information. The comparisons between empirical records and models in this study showed a better fit between the model and the real vibration data for the models that do consider the SSI using horizontal springs attached to the retaining walls of the underground stories. In addition, it was observed that applying a stiffness reduction factor of 0.7 to all elements in deformation verification models for average–height buildings was suitable to analyze the behavior under small earthquakes; better results are obtained embedding the structure in the foundation level than embedding in the street level; the use of horizontal springs with Kuesel’s model with traction for the analysis of the structure yields appropriate results; it is necessary to carefully select the spring constants to be used, paying special attention to the vertical springs. Even though the results presented herein indicate that the use of vertical springs to simulate the SSI of the base slab can result in major differences concerning the real response, it is necessary to obtain more data from instrumentation across a wider variety of structures to continue to evaluate better design and modeling practices. Similarly, further analyses, including nonlinear time–history and high–intensity events, are needed to best regulate building design.

Deformation Analysis and Research of Building Envelope by Deep Learning Technology under the Reinforcement of the Diaphragm Wall

“…When the cement-soil mixing pile is adopted to improve the base soil mass, the entire diaphragm wall or other envelope structure will have a certain distance from the reinforcement body formed by cement soil. Hence, it cannot be closely connected and can only be supplemented by grouting or high-pressure jet grouting [ 27 ]. The fourth method is grouting reinforcement.…”

Machine Learning-Based Rapid Post-Earthquake Damage Detection of RC Resisting-Moment Frame Buildings

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3-D Numerical Simulation of Seismic Response of the Induced Joint of a Subway Station

“…When considering the spatial effects of seismic damage in transfer subway stations with complex shapes, the seismic damage to the induced joints and structures can be more severe, resulting in significant economic, life, and property losses, which are difficult to repair after an earthquake. In recent years, a lot of research has been conducted on the seismic performance of underground structures and the response of different foundations and structures under earthquake action through theoretical analysis [1][2][3], experiment [4][5][6], and numerical simulation [7][8][9]. Some studies took the subway structure as the main research object and obtained results that provided a rich theoretical basis and practical experience for the improvement of earthquake resistance in subway construction.…”