Dynamic response of stand-alone and adjacent footing on saturated sand. Issue 143 (April 2021)

• Record Type: Journal Article
• Authors: Barrios, Gonzalo; Uemura, Kentaro; Kikkawa, Naotaka; Itoh, Kazuya; Larkin, Tam; Orense, Rolando; Chouw, Nawawi
• Is Part Of: Soil dynamics and earthquake engineering. Issue 143(2021)
• Publication Date: 2021-04
• Subjects: Centrifuge test -- Foundation-soil-foundation interaction -- Soil liquefaction -- Shallow footings; Soil dynamics -- Periodicals; Earthquake engineering -- Periodicals; Sols -- Dynamique -- Périodiques; Génie parasismique -- Périodiques; 624.176205
• DOI: 10.1016/j.soildyn.2021.106584
• Languages: English
• ISSNs: 0267-7261

Abstract

Abstract: This paper presents results from geotechnical centrifuge tests performed at the Japanese Institute of Occupational Safety and Health (JNIOSH) in Tokyo, Japan. A range of shallow footing configurations with different bearing pressures founded on saturated sand in a laminar box on a shake table was studied using harmonic excitations. The free-field condition was also studied as a reference. The study aimed to address the influence of stand-alone and closely adjacent shallow foundations on the dynamic response of the soil-foundation-structure system. A partially drained response of the soil and a minor dilative response for large values of shear strain were observed for the free-field case. In the case with footings, the settlement was found to be largely due to the footing penetrating the supporting sand. A dilative response of the soil beneath the footings was observed for the stand-alone configurations at the beginning of the base motions, this was not observed in the case of adjacent footings. Adjacent footings also tilt inwards consistently while stand-alone footings did not present a clear tilt pattern. In terms of the acceleration recorded in the near-surface soil beneath the footings, a reduction was observed after a few cycles in the free-field case. This reduction was considerably smaller in the case with footings with no significant differences between the response of the stand-alone and that of the closely adjacent footings. Highlights: Centrifuge tests of stand-alone and adjacent footings on a laminar box filled with saturated loose sand. The presence of footings modifies the portion of the soil with higher excess pore-pressure ratio. A partially drained response of the soil and a dilative response at large shear deformation are relevant for the settlement of the footings. The shallowest soil presented a similar response for all the base motions while the rest of the deposit tend to densify with subsequent shakes.