3107F.2.6 Steel Piles
The capacity of steel piles is based on allowable strains corresponding to the desired performance criteria and design earthquake.
When the plastic hinge forms in-ground, the plastic hinge length may be determined using Equation (7-21) [7.5]:
D = pile diameter
|CONNECTION TYPE||Lp AT DECK (in.)|
The following limiting value applies:
Strain at extreme-fiber, εu ≤ 0.035
The maximum allowable strain may not exceed the ultimate value defined in Section 3107F.2.6.4. Table 31F-7-7 provides limiting strain values for each performance level, for both new and existing structures.
Steel components for noncompact hollow piles (DP/t < 0.07 × E/fy) and for all nonseismic loading combinations shall be designed in accordance with AISC 325 [7.10].
|COMPONENTS||LEVEL I||LEVEL 2|
|Concrete Filled Pipe||0.008||0.030|
Level 1 or 2 refer to the seismic performance criteria (Section 3104F.2.1)
The procedures of Section 3107F.2.5.7, which are used to establish Vdesign are applicable to steel piles.
The shear capacity shall be established from the AISC 325 [7.10]. For concrete filled pipe, Equation (7-15) may be used to determine shear capacity; however, Vpile must be substituted for Vs.
t = steel pile wall thickness
fy,pile = yield strength of steel pile
c0 = distance from outside of steel pipe to center of hoop or spiral
[All other terms are as listed for Equation (7-18)].