Rocscience International Conference 2023 | April 24-26, 2023 Learn More about RIC2023
 

Search Results

13- Off-Shore Pile

1.0 Introduction

In the following tutorial, we will analyze an offshore pile installed in shallow sea water near the shore with uneven seabed and ground layers defined with 4 boreholes. (See the figure below.)

Want to watch the video version of the tutorial? Check it out here:

Problem description

The pile is a 20m long reinforced concrete bored pile with permanent casing for the first 9m. The pile diameter is 1m and the casing thickness is 25mm. The pile is reinforced with 12-25mm bars for the first 10m decreased to half for the rest of the pile.

The pile head is restrained from rotation for 1m because of the platform jacket. The loading case analyzed in this example is in one horizontal direction. The loads comprise of 50 kN from the jacket (divided for the purpose of analysis into two 25kN concentrated horizontal loads at pile head and 1m depth). In addition, the distributed wave load given as a traction +3.0 to -1.5 is approximated as linear loads.

The rotational restrains are modelled as very large stiffness values at +5 and +4.0 elevations. The concrete cylinder strength is taken as 40MPa, and the reinforcement bars have a yield strength of 420MPa and a modulus of elasticity of 200GPa while the casing has a yield strength of 350MPa.

Problem description

Topic Covered in this Tutorial:

  • Off-shore pile analysis
  • Lateral loads and tractions
  • Uneven Soil layers
  • Multiple boreholes
  • Surface water

Finished Product:

The finished product of this tutorial can be found in the Tutorial 13 - Off-Shore Pile data file. All tutorial files installed with RSPile can be accessed by selecting File > Recent Folders > Tutorials Folder from the RSPile main menu.

2.0 Project Settings

  1. Select Home > Project Settings project settings icon (CTRL + J).
  2. Select the General tab and enter the following:
    • Units = Metric
    • Program Mode Selection = Pile Analysis
  3. Go to the Pile Analysis Type tab and select Individual Pile Analysis > Laterally Loaded
  4. Go to the Groundwater tab and check the box for Groundwater Analysis.
  5. Set the Water Table Elevation to 3m
  6. Leave the Water Unit Weight (kN/m3) at its default value.
  7. Click OK to close the dialog.
Project Settings - Groundwater
Project Settings - Groundwater

3.0 Soils

3.1 Soil Properties

  1. Select Soils > Define Soil Properties Define Soil Properties icon icon in the toolbar.
  2. Enter the following soil properties:
  3. Soil Property 1:

    • Name = Loose Sand
    • Unit Weight = 14 kN/m3
    • Check box for Saturated Unit Weight = 16 kN/m3
    • Soil Type = Sand
    • Friction Angle = 27 degrees
    • Kpy = 4000 kN/m3
    • Kpy Saturated = 3000 kN/m
    Soil Properties - Loose Sand
    Soil Property 1 - Loose Sand


    Soil Property 2:

    • Name = Dense Sand
    • Unit Weight = 18 kN/m3
    • Check box for Saturated Unit Weight = 20 kN/m3
    • Soil Type = Sand
    • Friction Angle = 36 degrees
    • Kpy= 30000 kN/m3
    • Kpy Saturated = 25000 kN/m3
    Soil Property 2 - Dense Sand
    Soil Property 2 - Dense Sand


    Soil Property 3:

    • Name = Stiff Clay
    • Unit Weight = 18 kN/m3
    • Check box for Saturated Unit Weight = 20 kN/m3
    • Soil Type = Submerged Stiff Clay
    • Strain Factor = 0.005
    • Undrained Shear Strength (kPa) = 100 kPa
    • Ks = 135000 kN/m3
    Soil Property 3 - Stiff Clay
    Soil Property 3 - Stiff Clay
  4. Click OK to save your input and exit the dialog.

3.2 Edit Boreholes

  1. Select Soils > Edit All Borehole editor icon to open the Edit Borehole dialog.
  2. Add 3 boreholes by clicking the Add add button. There should be 4 boreholes total.
  3. Select Borehole 1. Click Insert Layer Below insert layer below twice to add the Dense Sand and Stiff Clay layers. Then enter the borehole information as per the table below:

Borehole

X, Y, Elevation

# Layer

Name

Thickness

Top Elevation

Bottom Elevation

Borehole 1

0,0,0

1

Loose Sand

3

0

-3

2

Dense Sand

6

-3

-9

3

Stiff Clay

20

-9

-29

Borehole 2

30,20,0

1

Loose Sand

5

0

-5

2

Dense Sand

5

-5

-10

3

Stiff Clay

20

-10

-30

Borehole 3

2,25,-1

1

Loose Sand

6

-1

-7

2

Dense Sand

6

-7

-13

3

Stiff Clay

20

-13

-33

Borehole 4

25,2,-2

1

Loose Sand

3

-2

-5

2

Dense Sand

4

-5

-9

3

Stiff Clay

20

-9

-29

Borehole Editor
Borehole Editor - Borehole 4


Your model should look as follows:

Model with Boreholes

4.0 Piles

4.1 Define Pile Section Properties

  1. Select Piles > Pile Sections define pile section properties to open the Define Pile Section Properties dialog.
  2. Create 3 Pile Sections Properties and name them as:
    • Pile Property 1.0
    • Pile Property 1.1
    • Pile Property 1.2
  3. For Pile Property 1.0 enter the following properties:
  4. Name

    Section Type

    Compressive Strength f’c (kPa)

    Cross Section

    Diameter (m)

    Pile Property 1.0

    Reinforced Concrete

    40000

    Circular

    1.0

    Define Pile Section Properties
    Define Pile Section Properties
  5. Click on the Concrete Designer Design.. button. Enter the information below:

Reinforcement Tab

Pattern 1

  • Rebar Size = Europe > BS4449 25mm
  • Pattern type = Radial
  • Number of Bars = 6
  • Angle from X Axis = 0
  • Cover Depth (mm) = 100
  • Yield Stress (kPa) = 420 000
  • Elastic Modulus (kPa) = 200 000 000
Concrete Designer - Reinforcement Pattern 1
Concrete Designer - Reinforcement Pattern 1


Pattern 2

  • Rebar Size = Europe > BS4449 25mm
  • Pattern type = Radial
  • Number of Bars = 6
  • Angle from X Axis = 30
  • Cover Depth = 100 mm
  • Yield Stress = 420 000 kPa
  • Elastic Modulus = 200 000 000 kPa
Concrete Designer - Reinforcement Pattern 2
Concrete Designer - Reinforcement Pattern 2


Casing Tab

  • Casing Thickness = 25 mm
  • Yield Stress = 350 000 kPa
  • Elastic Modulus = 200 000 000 kPa
Concrete Designer - Casing tab
Concrete Designer - Casing tab
  1. In the Define Pile Section Properties dialog, select the Copy icon to copy the Pile Property 1.0 to Pile Property 1.1 and Pile Property 1.2. Select both pile properties and click OK.
    Copy Pile Properties
    Copy Pile Properties
  2. In the Pile Section Properties dialog select Pile Property 1.1:
    • Click on the Concrete Designer Design.. button.
    • Go to the Casing tab.
    • Uncheck Add Casing.
    • Click OK to close the Concrete Designer dialog.
  3. In the Pile Section Properties dialog select Pile Property 1.2:
    • Click on the Concrete Designer Design.. button.
    • Delete Pattern 2.
    • Go to the Casing tab.
    • Uncheck Add Casing.
    • Click OK to close the Concrete Designer dialog.
  4. Click OK to close the Pile Section Properties dialog.

4.2 Edit Pile Types

  1. Select Piles > Pile Types Define Pile Types icon to open the Edit Pile Types dialog.
  2. In the Sections tab, set Pile Head Elevation = 5m and Cross Section Type as Uniform.
  3. Click the Insert Layer Below insert layer below icon button twice to add sections 1.1 and 1.2.
  4. Edit the Length (m) of the Pile Section Properties as per the table below.

Section Property

Length (m)

Top Elevation (m)

Bottom Elevation (m)

Pile Property 1.0

9.00

5.00

-4.00

Pile Property 1.1

1.00

-4.00

-5.00

Pile Property 1.2

10.00

-5.00

-15.00

Define Pile Type
Define Pile Type - Pile Type 1

4.3 Add Pile

  1. Select Piles > Single Add single pile icon icon to open the Add Pile dialog.
  2. In the Geometry tab, toggle off the Mouse icon to specify the Pile 1 Location as X = 14 and Y = 14.
    Add Pile
    Add Pile - Geometry
  3. In the Loading tab, click the Add add icon icon to add a Load Property.
  4. For the Loading Direction select General.
  5. Click on the Add add icon icon in the bottom left and add the loads as per the table below:

Type

Value

Depth

Shear X (kN)

25

0

Shear X (kN)

25

1

Rotational Stiffness Y (kNm/rad)

1e+09

0

Rotational Stiffness Y (kNm/rad)

1e+09

1

Add Pile - Loading
Add Pile - Loading
  1. In the Tractions tab click the Add Add icon icon to add a Traction Property.
  2. Click on the Add Add icon icon in the bottom left to add the traction loads as per the table below:

Direction

Top Value (kN/m)

Top Depth (m)

Bottom Value (kN/m)

Bottom Depth (m)

Axis X

6

2

4

5

Axis X

4

5

3

6.5

Add Pile - Tractions
Add Pile - Tractions
  1. Click OK to close the dialog and place the pile.

5.0 Compute

  1. Select Home > Compute Compute icon to save and compute the model.

6.0 Results

Results

Account Icon - click here to log in or out of your account Shopping Cart icon Click here to search our site Click here to close Learning Tech Support Documentation Info Chevron Delete Back to Top View More" PDF File Calendar Location Language Fees Video Click here to visit Rocscience's LinkedIn page Click here to visit Rocscience's YouTube page Click here to visit Rocscience's Twitter page Click here to visit Rocscience's Facebook page Click here to visit Rocscience's Instagram page Bookmark Network Scroll down for more Checkmark Download Print Back to top Single User Multiple Users RSLog RocFall3 CPillar Dips EX3 RocFall RocPlane RocSupport RocTopple RS2 RS3 RSData RSPile Settle3 Slide2 Slide3 SWedge UnWedge Commercial License Education License Trial License Shop safe & secure Money-back guarantee