1. Driven Pile Design George Goble

2. Basic LRFD Requirement η k Σ γ ij Q ij ≤ φ g R ng η k – factor for effect of redundancy, ductility and importance γ ij – Load factor for the i th load type in the j th load combination Q ij – The i th load type in the j th load combination φ g – The resistance factor for the a th failure mode R ng - The nominal strength for the a th failure mode

3. Definition of Loads N – Axial loadDC – Structural Dead Load FT – Load transverse to the LL – Vehicular Live Load bridge centerline FL – Load parallel to the IM – Vehicular Dynamic Load bridge centerline MT – Moment about the ML – Moment about the transverse axis longitudinal axis WL – Wind on Live LoadBR – Vehicular Braking WS – Wind Load on Structure Force Note: Two different wind loads are specified – winds greater than 55 miles per hour and winds less than 55 miles per hour. At greater than 55 miles per hour no traffic loads are included

4. Force Effects Load Set 1, Maximum axial effect with overturning effect All units are kips and feet LOAD N FT FL MT ML DC 5564 0 0 0 0 LL 894 0 0 0 3742 WS (>55)-254 182 145 4334 5454 WS (<55)-142 107 66 1961 3226 WL 0 20 -4.2 -125 600 BR 0 24.2 -54.5 -1636 727

5. Force Effects Load Set 2, Maximum overturning effect with axial effect All units are kips and feet LOA N FT FL MT ML DC 5564 0 0 0 0 LL 6620 0 0 12552 WS (>55) -254 182 145 4334 5454 WS (<55) -142 107 66 1961 3226 WL 0 20 -4.2 -125 600 BR 0 17.9 -40.0 -1208 537

6. AASHTO Load Combinations STR I MAX = 1.25 DC + 1.75 (LL + IM + BR) STR I MIN = 0.9 DC + 1.75 (LL + IM + BR) STR III = 0.9 DC + 1.4 WS STR IV = 1.5 DC STR V MAX = 1.25 DC + 1.35 (LL + IM + BR) + 0.4 WS + 1.0 WL STR V MIN = 0.9 DC + 1.35 (LL + IM + BR) + 0.4 WS + 1.0 WL

7. Table 2 Factored Loads LOADN FTFL MT ML z x y Mx My STR I MAX 8520 42 -95 -2863 7821 STR I MIN 6166 31 -71 -2114 22906 STR III 4652 255 2036068 7635 STR IV 83460 0 00 STR V MAX 8105 95 -51 -1549 7924 STR V MIN 5845 87 -32-971 19561

8. Soil Boring

9. TRY 18 inch Square Prestressed Concrete pile Use 7000 psi Concrete Structural Axial Strength –P n = 0.80 [ 0.85f’ c A g –(f pe - 85.5) A g ] –P n = 1360 kips

11. Wave Equation Results D-36-32 Hammer 3 inches plywood !! Capacity 1100 kips Blow Count 10 Blows per inch Maximum Compression Stress 3.6 ksi Allowable Driving Stress –φ(0.85f’ c - f pe ), - φ = 1.0 –For 7.0 ksi Concrete, Allowable Stress = 5.1 ksi

12. Wave Equation Bearing Graph

13. Concrete Stress-Strain Curve

14. Trial No. 1 1100 kips Pile Capacity 16, 18 inch Square Piles 4 x 4 Group FB-Pier Input –Structural Elements and Material Properties –Soil Properties –Structural Geometry –Loads Lateral – O’Neil Sand Model DRIVEN Axial Model –Increase Axial Capacity by a Factor of 2.0 Effective Prestress – 800 psi Linear Analysis – No P-Δ – But Non-Linear Soil

15. Results Several Tries - 4 x 4 Group Doesn’t Work – Pile Top Structural Failure Change to 20 Inch Square Pile – 4 x 4 Group Very Safe Try 3 x 4, 20 Inch Pile Group Successful After Several Trials

16. Final Design

17. Results

18. Bi-Axial Interaction Diagram Pile 4, Load Case 2

19. Critical Conditions Load CaseMax. Pile Load, Pile No. Kips Max. Uplift Load, Pile No. Kips Demand/Capacity Ratio, Pile No. Str I Max847, 90.700 Str I Min79168, 40.654 Str III5611.000, 4 Str IV6910.570 Str V Max7830.673 Str V Min7120.649

20. Required Axial Capacity R n = Un-Factored Capacity/φ R n = 847/0.80 R n = 1060 kips

21. Wave Equation Analysis

22. Final Requirements 12, 20 Inch Square Piles Estimated Length – 85 Feet – (Bottom of Cap, -10 Feet) Required Blow Count – 80 Blows per Foot Maximum Compression Stress – 3.3 ksi Maximum Tension – 1.5 ksi – Excessive, Throttle Back