000018742 001__ 18742
000018742 005__ 20170118182239.0
000018742 04107 $$aeng
000018742 046__ $$k2017-01-09
000018742 100__ $$aMylonakis, George
000018742 24500 $$a3d Dynamic Impedances of Surface Footings on Liquefiable Soil: Equivalent Linear Approach

000018742 24630 $$n16.$$pProceedings of the 16th World Conference on Earthquake Engineering
000018742 260__ $$b
000018742 506__ $$arestricted
000018742 520__ $$2eng$$aRecent experimental and theoretical studies suggest that deep foundations may be avoided in a liquefaction regime, in the presence of a non-liquefiable layer on top of the liquefiable of adequate thickness and shear strength, which can restrain the accumulation of excessive seismic settlements and prevent post-shaking bearing capacity failure. This evidence has given rise to attempts for a complete design approach for the performance-based design of shallow foundations on liquefiable soils [1 – 3]. The design is based on the idea of a permeable crust (natural or artificial) which needs not extend over the whole depth of the liquefiable sand in order to take advantage of the observed benefits of settlement reduction [4, 5] at a reduced thickness and width. Within the above context the need arises to investigate the dynamic response of shallow foundations on liquefiable soils. The focus of the present study is upon the influence of liquefaction on the dynamic stiffness and damping (“impedance” functions) of rigid square footings resting on a multilayer soil profile involving a liquefiable layer, under external harmonic loading. To this end, a three-layer soil profile consisting of a surface clayey crust over a loose liquefiable sandy layer followed by a stiff impervious base stratum, are considered. The dynamic impedance of a rigid square footing is investigated parametrically using computer software CONAN [6], which is based on wave propagation in cones. A limited number of rigorous 3D numerical analyses with boundary elements [7] was also performed to check the accuracy of the cone models. Vertical, horizontal and rocking oscillations are considered. The results show that for common soil, foundation and seismic excitation conditions, liquefaction in the foundation soil leads to significant degradation of the dynamic spring coefficients and increase of the associated damping coefficients.

000018742 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000018742 653__ $$adynamic impedance; surface footing; liquefiable soil; 3-layer soil profile

000018742 7112_ $$a16th World Conference on Earthquake Engineering$$cSantiago (CL)$$d2017-01-09 / 2017-01-13$$gWCEE16
000018742 720__ $$aMylonakis, George$$iBouckovalas, George$$iKaratzia, Xenia
000018742 8560_ $$ffischerc@itam.cas.cz
000018742 8564_ $$s875174$$uhttps://invenio.itam.cas.cz/record/18742/files/2126.pdf$$yOriginal version of the author's contribution as presented on USB, paper 2126.
000018742 962__ $$r16048
000018742 980__ $$aPAPER