Seismic performance and improvements of split-foundation buildings in across-slope direction

Abstract

The seismic performance and damage pattern of the split-foundation frame buildings in across-slope direction are studied. In view of the characteristics of split-foundation structure, the parameter analyses of split-foundation structure with different spans and floors of lower and upper parts are studied, and the main factors affecting the torsional effect of split-foundation structure are also studied theoretically. Finally, the improvements and design procedure of split-foundation structure are put forward to reduce the difference in ductility demands between the upper ground columns and the lower part. Results show that the torsional effect of split-foundation structure is very significant because of the rigidity eccentric. The upper ground columns are the weakest parts of split-foundation structure which are destroyed first under the earthquake action; then, the lower floors are destroyed in succession. Lower ductility demands of the upper ground columns and better seismic performance of the split-foundation structure can be achieved by the designed improvements.

Seismic fragility analysis of coupled building‐slope systems

“…They have identified six types of structural configurations: SC A—buildings with foundations at the same level, i.e., buildings located on a flat patch of ground, either existing naturally or made by cutting the hill slope; SC B—buildings with foundations at two different levels; SC C—‘step‐back’ buildings with foundations at multiple levels along the hill slope; SC D –‘step‐back set‐back' buildings, not only having the foundations at multiple levels following the natural slope, but the roof‐line also following the slope; SC E—buildings with foundations located at the same level, partly on the natural ground and partly on an artificially created platform by retaining soil using a retaining wall; and SC F—buildings similar to the SC C having foundation at multiple levels, but supported on stilts. Similar building typologies have also been reported in the hilly regions of China 25,26,65 . Surana et al 29 .…”

“…In case of buildings located on slopes, the foundations are placed at different levels, resulting in columns of varying heights causing irregular structural configurations. [25][26][27][28] It is reported in the past studies 29 that the irregular structural configuration alone can cause a significant increase in the collapse probability of hill-side buildings. The foundation typology and supporting ground conditions (including stratigraphy and topography) are additional important parameters, which govern the seismic vulnerability of buildings located on slope.…”

“…Only a few studies are available on seismic fragility for buildings located on slopes. Most of the past studies have considered only the effect of the irregular configurations of the hill-side buildings, ignoring slope-building interaction (SBI), 26,[29][30][31][32][33][34][35] whereas others [36][37][38][39] have considered the topographic effect and nonlinear slope movement but have ignored the effect of irregular structural configuration. Fotopoulou, Pitilakis 36 used a two-step uncoupled approach to assess the vulnerability of low-rise (single storey, single bay) reinforced concrete (RC) frame buildings supported on isolated and continuous slab foundation.…”

“…In case of buildings located on slopes, the foundations are placed at different levels, resulting in columns of varying heights causing irregular structural configurations 25–28 . It is reported in the past studies 29 that the irregular structural configuration alone can cause a significant increase in the collapse probability of hill‐side buildings.…”

“…Plan and elevations of buildings: (A) Plan; (B) Elevation on 20 • slope; (C) Elevation on 30 • slope.regions of China 25,26,65. Surana et al29 have reported that SC C is the most common building typology in this region, and the same has been chosen in the present study.…”