Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Mitigation of Seismic Hazards Vulnerability by Jet Grouting to Encase Existing Piles
The state of California has stringent seismic standards for schools. Many buildings built prior to the 1960s are seismically vulnerable because the hazard from liquefaction had not been recognized. The state has instituted a program to identify and evaluate buildings with excessive risk of catastrophic collapse from seismic hazards. School buildings listed under this program were evaluated in accordance with ASCE 31 standards. Those buildings found to have excessive risk of collapse require replacement or rehabilitation under the program. Liquefaction can induce a reduction in or loss of bearing capacity. It can also cause excessive volumetric settlements. These effects could compromise a foundation that is not designed to withstand them. Two cases with similar foundations are compared and contrasted to further enlighten how existing foundations can be salvaged and reused to prevent unnecessary demolition and replacement. This will increase sustainability and wise use of scarce public resources. Two buildings founded on shallow piles that do not penetrate through all the liquefiable layers were studied. The underlying geology is similar for both buildings, and the depth to a firm bearing layer is very deep. Mitigation of the loss of bearing capacity and excessive settlement was possible at one building while not at the other. Subtle differences in the location and depths of the liquefiable layers allowed the salvage of the foundation of one of the buildings studied. Mitigation of the loss of bearing was provided by design of a jet grouting program to encase the existing piles and extend them to an intervening clay layer. The base of the encasement was designed with a larger diameter, thus effectively creating a belled pile that could bear on the intervening layer and prevent a plunging failure of the piles. The jet grouting method was the only method that could reasonably salvage the building foundation.
Mitigation of Seismic Hazards Vulnerability by Jet Grouting to Encase Existing Piles
The state of California has stringent seismic standards for schools. Many buildings built prior to the 1960s are seismically vulnerable because the hazard from liquefaction had not been recognized. The state has instituted a program to identify and evaluate buildings with excessive risk of catastrophic collapse from seismic hazards. School buildings listed under this program were evaluated in accordance with ASCE 31 standards. Those buildings found to have excessive risk of collapse require replacement or rehabilitation under the program. Liquefaction can induce a reduction in or loss of bearing capacity. It can also cause excessive volumetric settlements. These effects could compromise a foundation that is not designed to withstand them. Two cases with similar foundations are compared and contrasted to further enlighten how existing foundations can be salvaged and reused to prevent unnecessary demolition and replacement. This will increase sustainability and wise use of scarce public resources. Two buildings founded on shallow piles that do not penetrate through all the liquefiable layers were studied. The underlying geology is similar for both buildings, and the depth to a firm bearing layer is very deep. Mitigation of the loss of bearing capacity and excessive settlement was possible at one building while not at the other. Subtle differences in the location and depths of the liquefiable layers allowed the salvage of the foundation of one of the buildings studied. Mitigation of the loss of bearing was provided by design of a jet grouting program to encase the existing piles and extend them to an intervening clay layer. The base of the encasement was designed with a larger diameter, thus effectively creating a belled pile that could bear on the intervening layer and prevent a plunging failure of the piles. The jet grouting method was the only method that could reasonably salvage the building foundation.
Mitigation of Seismic Hazards Vulnerability by Jet Grouting to Encase Existing Piles
Montgomery Schultz, John (Autor:in) / Jafroudi, Siamak (Autor:in)
Geo-Congress 2014 ; 2014 ; Atlanta, Georgia
Geo-Congress 2014 Technical Papers ; 3754-3768
24.02.2014
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
Mitigation of Seismic Hazards Vulnerability by Jet Grouting to Encase Existing Piles
| British Library Conference Proceedings | 2014
Jet Grouting Slabs and Jet Grouting Piles
| Springer Verlag | 2021
Seismic investigation methods for the testing of jet-grouting piles
| Tema Archiv | 2001
Seismic vulnerability of existing buildings
| TIBKAT | 2002