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Pile Design 1
ROBERT SIQECA, PE
PAGE BY:
PROJECT: 920 Westchester Ave, BX, NY JOB # CHK'K: RS
ITEM: Pile design DATE:
Foundation Wall Data:
f 'c, grout strength = 5 ksi
f'c_f, footing concrete strength = 4 ksi
f 'y c steel strength casing = 60 ksi
f 'y b steel strength bar = 75 ksi
, strength reduction factor for shear = 0.75
Area grout= = 52 in2
Area bar= = 2.25 in2
(no 14. threaded bar)
Area casing= = 11.9 in2
(HSS 8.625x0.500)
Plunge length= = 5 ft
Dia casing= 8.625 in
Dia bond= = 10 in
RS
1531
1 OF6
8/2/2010
920 Westchester Ave
Pile Design 2
1. Pile Cased Length (Service Load Design)
For strain compatibility between casing and bar, use the following for steel
yield stress:
F y-steel = the minimum of Fy bar & Fy casing= 60 ksi
Tension - Allowable load
Pt -allowable = 0.55 Fy steel x ( Area bar + Area casing)= 424.5 kips
(Note: 0.55 is per AASHTO Table 10.32.1A)
Tension Allowable load :
Fa = Fy-steel/FS . . . . . FS = 2.12
P c -allowable = 0.40fc-grout Area gout + 0.47Fy-steel [Area bar + Area casing]
= 503.03 kips
(Note: 0.40 is per AASHTO 8.15.2.1.1; 0.47 is per AASHTO, i.e. 1/2.12 = 0.47)
2.Pile Uncased Length (Service Load Design)
Cased bond length (plunge length) allowable load = P transfer allowable
= 257,717 lbs
bond nominal strength = geotechnical unit grout-to-ground bond strength= 2000 kpa
= 290 psi
920 Westchester Ave
Pile Design 3
Tension - Allowable load
P t-allowable = 0.55 Fy bar x Area bar + P transfer allowable= 350.5 kips
(Note: 0.55 is per AASHTO Table 10.32.1A)
Compression - Allowable load
P c-allowable = 0.4fc-grout x Area grout + 0.47 Fy bar x Area bar + P transfer allowable=
= 441.0295 kips >> 300 kips ok
(Note: 0.40 is per AASHTO 8.15.2.1.1; 0.47 per AASHTO, i.e 1 /2.12 = 0.47)
920 Westchester Ave
Pile Design 4
3. Pile to Footing Connection
a. bond between the pile casing and the footing concrete:
bond btwn casing & footing= 1.75 Mpa= 253.8 psi
casing embedment= 6 in
P casing bond= (bond btwn casing & footing/FS)x3.14xD casing x Casing embedment
= 20,617 lbs
920 Westchester Ave
Pile Design 5
b. Check if compression load can be transferred through bearing on pile top(figure 5-8) without optional
bearing plate:
Pn, max = 323,159 lbs
Pn, max + Pcasing bond = 343,776 lbs < 300 kips
Detail in Figure 5-8 cannot work.
c.Design for bearing plate without stiffeners
Pu=300kips- P casing bond= 279.38 kips
920 Westchester Ave
Pile Design 6
109.56 in2
Use 11"x11" plate
2.05 in
fp=Pu/ 3.14*Dia casing = 10.316 ksi
tp= 0.803 in
Use 11x11x1" bearing plate
920 Westchester Ave