GTSTRUDL User’s GroupGTSTRUDL User’s Group

BASE PLATE ANALYSIS

June 23, 2011Parimal Gandhi, PE

Sr. Engineer1

Annual Meeting - 2011Annual Meeting - 2011

PURPOSE

Non-Linear Finite Element Analysis For Base Plate.

AND

Stiffness Analysis For Base Plate.

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AGENDA

1. INTRODUCTION AND THEORY

2. BASE PLATE MODELING

3. EDIT THE BASE PLATE INPUT FILE

4. BASE PLATE STRESSES & BOLTS LOADS

5. FLEXIBLE & RIGID BASE PLATE RESULTS

6. CONCLUSION3

Introduction & Theory

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The finite element method is used to analyze the base plate considering the beam on elastic foundation.

The concrete and bolts are represented by non linear spring elements attached to the nodal points on the steel base plate and to the ground.

The steel base plate is modeled with SBHQ6 and SBHT6 plate bending element.

Attachments and Stiffeners are modeled as RIGID SOLIDS in the plane of the base plate.

Introduction & Theory

The Beam on Elastic Foundation5

Introduction & Theory

Non Linear Spring Element

Concrete

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Introduction & Theory

Non Linear Spring Element

Bolt

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Introduction & Theory

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Non-linear Spring Curves

Base Plate Modeling

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Base Plate Modeling

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Circular Base Plate Modeling

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Circular Base Plate Modeling

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Circular Base Plate Modeling

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Circular Base Plate Modeling

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Circular Base Plate Modeling

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Circular Base Plate Modeling

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Circular Base Plate Modeling

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Circular Base Plate Modeling

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Elements=24x12=288

Joints=289

Joint 289Element 288

Edit Base Plate Input FileThe GT Model Wizard creates a GTSTRUDL input file that remains after the Wizard is closed.

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Edit Base Plate Input FileSoil Spring Values

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Edit Base Plate Input FileFor Attachment

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Master Joint ‘C1’

Slave Joints 74 to 97

Edit Base Plate Input FileFor Concrete Stiffness

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Edit Base Plate Input FileFor Concrete Stiffness

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Edit Base Plate Input FileFor Bolt Stiffness

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Edit Base Plate Input FileFor Bolt Stiffness

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Edit Base Plate Input File

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LOADING

Output

Non Linear Analysis

Base Plate Stresses

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Bolt Support Reactions

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

Base Plate odeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

Base Plate Modeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

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Square /Rectangular Base Plate Modeling

Total Joints =169

Total Elements =144

zX

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Square /Rectangular Base Plate Modeling

Master Joint ‘C1’

Slave Joints 57, 61 … 113

Spring Element ‘S1’ Spring Element

‘S169’

Edit Base Plate Input File

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``

LOADING

Output

Non Linear Analysis

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Square /Rectangular Base Plate Stresses

B1 B2

B3 B4

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Support Reactions for Bolts

Edit Rigid Base Plate Input File

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Rigid Attachment

Output

Bolt : Pinned Support

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``

Stiffness Analysis

Loading

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Flexible & Rigid Base Plate Result

Non-Linear Base Plate AnalysisWith Concrete &

Bolt Stiffness

Linear/Stiffness Base Plate AnalysisWithout Concrete

& Bolt StiffnessMaximum Bolt

Pull outMaximum Shear

LoadBase Plate Stresses

Base Plate Displacement

339 lbs 423 lbs

949 lbs 949 lbs

9215 psi 9404 psi

Δy=0.00361” Δy=0.00432”

Flexible Rigid

Questions?Questions?

Thank you.Thank you.

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