Liquefaction Foundation Mats

Soil liquefaction has caused major damage to superstructures resting on shallow foundations during past earthquakes.

Liquefaction foundation mats.

A stiff foundation mat below is a good type of shallow foundation which can transfer loads from locally liquefied zones to adjacent stronger ground. Soil stiffness is greatly decreased as a result of excess pore water pressure epwp generation and the consequent effective stress reduction. Site liquefaction and liquefaction induced lateral spreading in the feb. I a benchmark test without a liquefaction countermeasure ii foundation densiflcation below the embankment toe and iii use of a sheet pile containment.

Deep foundation aspect liquefaction can cause large lateral loads on pile foundations. A stiff foundation mat can transfer loads from areas of weakness to areas of strength in the soil thus. Complete analysis design of a mat or raft foundation analyses uniform thickness finite mat or raft foundation with free ends and supported by a beam on elastic foundation. Shallow foundation detailing mat foundation detailing reinforcing each way top and bottom detail according to aci 318 14 section 18 6 3 1 minimum longitudinal reinforcing only or design to accommodate expected differential settlements elastic design consistent with small permitted differential settlements.

Spreadsheets are hard. Buried utilities such as sewage and water pipes should have ductile connections to the structure to accommodate the large movements and settlements that can occur due to liquefaction. The experimental series included. 22 2011 christchurch mw6 3 earthquake especially caused severe damage to about 15000 residential buildings 1000.

Use of robust mats or a stiff grid of intersecting ground beams instead of stand alone footings. Piles driven through a weak potentially soil layer to a stronger layer not only have to carry vertical loads form the superstructure but must also be able to resist horizontal loads and bending moments induced by lateral movements if the weak layer liquefies.