Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Helical Pile Capacity to Torque Ratios, Current Practice, and Reliability
Historic helical pile ultimate capacities and capacity to torque ratios (Kt) were based upon full-scale tension load tests where ultimate load was taken at deflections near plunge. In 2005, nine helical pile manufacturers joined together in an effort to standardize evaluation requirements for manufacturers seeking approval under International Code Council Evaluation Service (ICC-ES). The result of their efforts was the creation of "Acceptance Criteria for Helical Foundations Systems and Devices" (AC358). AC358 now provides standardized guidelines for evaluation of helical piles that includes a net deflection limit at ultimate load equal to 10% of the average helix diameter. CTL Thompson, Inc. has performed 93 full-scale compression and 109 full-scale tension load tests conducted on behalf of five different helical pile manufacturers seeking ICC-ES evaluation reports under the criteria set forth by AC358. Measured ultimate capacities (Qm) were compared to calculated ultimate capacities (Qu) using AC358 capacity to torque ratios, bearing of the individual blades, and cylindrical shear methods. Statistical analysis of these results shows that helical piles in compression designed with the least Qu determined from torque ratios (Kt), bearing of individual blades, and cylindrical shear methods have a high reliability for all blade configurations. Whereas helical piles in tension based upon the least Qu determined from torque ratios, bearing of individual blades, and cylindrical shear methods have varying reliability depending on blade configuration. Therefore, more study is necessary to determine reliability in tension.
Helical Pile Capacity to Torque Ratios, Current Practice, and Reliability
Historic helical pile ultimate capacities and capacity to torque ratios (Kt) were based upon full-scale tension load tests where ultimate load was taken at deflections near plunge. In 2005, nine helical pile manufacturers joined together in an effort to standardize evaluation requirements for manufacturers seeking approval under International Code Council Evaluation Service (ICC-ES). The result of their efforts was the creation of "Acceptance Criteria for Helical Foundations Systems and Devices" (AC358). AC358 now provides standardized guidelines for evaluation of helical piles that includes a net deflection limit at ultimate load equal to 10% of the average helix diameter. CTL Thompson, Inc. has performed 93 full-scale compression and 109 full-scale tension load tests conducted on behalf of five different helical pile manufacturers seeking ICC-ES evaluation reports under the criteria set forth by AC358. Measured ultimate capacities (Qm) were compared to calculated ultimate capacities (Qu) using AC358 capacity to torque ratios, bearing of the individual blades, and cylindrical shear methods. Statistical analysis of these results shows that helical piles in compression designed with the least Qu determined from torque ratios (Kt), bearing of individual blades, and cylindrical shear methods have a high reliability for all blade configurations. Whereas helical piles in tension based upon the least Qu determined from torque ratios, bearing of individual blades, and cylindrical shear methods have varying reliability depending on blade configuration. Therefore, more study is necessary to determine reliability in tension.
Helical Pile Capacity to Torque Ratios, Current Practice, and Reliability
Cherry, James A. (Autor:in) / Souissi, Moncef (Autor:in)
Biennial Geotechnical Seminar 2010 ; 2010 ; Denver, Colorado, United States
GeoTrends ; 43-52
27.10.2010
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
Large-diameter helical pile capacity – torque correlations
| Online Contents | 2017
Large Diameter Helical Pile Capacity - Torque Correlations
| Online Contents | 2017
Large-diameter helical pile capacity — torque correlations
| British Library Online Contents | 2017