Geotechnical Engineering Circular No. 9 Design, Analysis, and Testing of Laterally Loaded Deep Foundations that Support Transportation Facilities
Download 6.03 Mb. View original pdf
|
Soldier Rev B
| 6.4 COM624P MANUAL (1993) The COMP manual, authored by Wang and Reese, focuses on the usage of the referenced software which is based on the p-y methodology. It offers no specific design guidance but, similar to Reese (1984, 1985), discusses the concept of critical penetration. The reference notes that there is no discernable difference between analyses where more than two points of zero deflection are present. It states that to save computation time the pile can be shortened so that there are two or three points of zero deflection. 6.5 AMERICAN PETROLEUM INSTITUTE (API) (2000) API (2000) presents methods for determining the ultimate lateral bearing capacity for soft clay, stiff clay, and sand and for generating p-y curves for the same soil types. It additionally recommends that due to API-sponsored studies that multiple methods should be employed to assess group effects of lateral loads and that upperbound and lowerbound soil parameters be used. 6.6 FHWA NHI-10-016: DRILLED SHAFTS CONSTRUCTION PROCEDURES AND LRFD DESIGN METHODS (2010) Presents a detailed design process which includes Geotechnical Strength Limit State (pushover analysis uses p-y method to analyze linear elastic shaft with factored loads and a factored resistance to define the Limit State based on ahead deflection that is less than 10 percent of the shaft diameter. Structural Strength Limit State uses p-y method to confirm that nominal axial, shear, and flexural resistance exceed the factored axial, shear, and bending moments using the nonlinear flexural stiffness cracked section) of the shaft. Service Limit State uses the p-y method and service loads to confirm that deflection is acceptable using the nonlinear flexural stiffness of the shaft (cracked section. For the first stage listed above, resistance factors (Φ) are presented for various design conditions ranging from 0.40 to 0.80. The resistance factors are not applied directly to soil strengths, but instead as an inverse (1/Φ) applied to the factored overturning forces. The use of resistance factors for lateral analysis is more conservative than the AASHTO design specifications. |