Design of Laterally Loaded Monopiles

in Normally to Moderately

Overconsolidated Clays

Asitha Senanayake, Hande Gerkus & Bob GilbertThe University of Texas at Austin

Erica Rendon & Shin-Tower WangEnsoft Inc.

Bob StevensFugro-McClelland Marine Geosciences

Dan O’Connell & Sid FalkBureau of Ocean Energy Management

Objectives

1. Assess Effect of Large Pile Diameters

2. Evaluate Suitability of p-y Curves

3. Investigate Effects of Cyclic Loading

4. Develop Design Recommendations

Pile Diameter

3D FEM Mesh

Pile Diameter

p-y Curves

p-y Curves

D=4-inches

p-y Curves

D=2-inchesD=4-inches

p-y Curves

Marine Clay

p-y Curves

p-y Curves

p-y Curves

54-inch Diameter Pile

New Orleans (2010)

p-y Curves

12.75-inch Diameter Pile

Sabine River (1961)

Cyclic Loading

Cyclic Loading

Cyclic Loading

Conclusions: Laterally Loaded

Monopiles in Normally to Moderately

Overconsolidated Clays

1. Normalizing p-y Curves by Diameter and

Ultimate Lateral Resistance Captures Effect of

Pile Diameter

2. Jeanjean (2009) p-y Curves Fit Laboratory and

Field Data Better than Matlock (1970) Curves

3. Secant Stiffness of Lateral Pile-Soil Response

Degrades by 20% to 30% within about 100

Cycles and then Stabilizes

4. Ultimate Lateral Capacity of a Pile Is Not

Affected by Previous Cyclic Loading

Future Work

1. Laterally Loaded Monopiles in Sand

2. Measuring Small-Strain Stiffness In Situ