Numerical Investigation of Bracing Configuration Efficiency on the Seismic Performance of High-Rise Buildings Considering Soil–Structure Interaction

Soil–structure interaction (SSI) alters stiffness, damping, and load paths in braced high-rise frames, but the comparative efficiency of bracing layouts under SSI remains insufficiently quantified. This study numerically evaluates a ۱۵-story reinforced-concrete frame on clay soil using Hardening soil with small-strain stiffness soil model (HSsmall)using PLAXIS ۲D, testing five steel bracing configurations—X, K, V, inverted-V, and single diagonal—subjected to three recorded earthquakes (Northridge, Imperial Valley, Kocaeli). Response metrics include interstory drift ratio (IDR), roof displacement relative to the moving base, raft rotation, and settlement. The bracing schemes and the small-strain soil formulation are detailed to ensure like-for-like comparison under SSI. Across free-vibration checks, SSI lengthened the fundamental period relative to a rigid base, confirming the role of foundation compliance. Under Northridge and Imperial Valley, bracing reduced peak IDR by ~۴۴–۴۸% and ~۴۶% (from ~۱.۰۱% and ۰.۸۰% to ۰.۴۳–۰.۵۶%), with K and X consistently top performers and the diagonal layout least effective. For Kocaeli, drift gains were smaller (۳۱–۳۷%), reflecting longer-period content and narrowing performance gaps. Roof-drift reductions were modest overall, whereas bracing frequently increased foundation rotation (with record dependence), revealing a drift–foundation-demand trade-off under SSI. These results indicate that configuration choice under SSI is motion-dependent; K/X provide robust drift control, but designers should verify raft serviceability where stiffening could elevate rocking and settlement demands.

کلیدواژه ها:

Soil-structure interaction ، Steel Bracing ، seismic analysis ، Interstory drift ratio ، Foundation rotation