ECDYN - Dynamic Foundation Design

This part of user manual describes how to use ECDYN analysis of Dynamic Foundation. ECPlus applications are designed as wizard type which is a step by step guided input procedure. If you are new to ECPlus applications, click here for general guidance.

Prerequisites: The user is expected to have basic understanding on Analysis of Dynamic foundation.
The minimum input data required to use this application is as follows:

• ❶ Soil and Dynamic Criteria.
• ❷ Allowable stability factors.
• ❸ Base Block and Machine Component details.
• ❹ Dynamic and Non-dynamic Loading.

Technical reference for ECDYN can be found here.

Following sections are presented with various input pages of ECDYN application with descriptions:

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Analysis Options

This page allows to select Dynamic Analysis Method, Time History Chart Type for Report and Unit.

Dynamic Analysis Method

Select the method for the dynamic analysis.
☉Richard - Lysmer ( Elastic Half Space Theory ) : Select this option to use Richard method for the dynamic analysis.
☉Barkan ( Linear Elastic Spring Theory ) : Select this option to use Barkan method for the dynamic analysis.

Time History Chart Type for Report

☉High Quality : Select this option to generate time history chart in higher quality.
☉Medium Quality : Select this option to generate time history chart in medium quality.
☉Nil : Select this option, if time history chart is not needed.

Unit

☉SI Unit (m, kN) : Select this option to proceed with SI units.
☉Imperial (ft, kips) : Select this option to proceed with Imperial units.

While Switching Unit:

☐  Reset to Default : Select this option to reset all values with default values, on switching between units using above option.
☐  Convert Inputs : Select this option to convert the input values, on switching between units using above option.

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Foundation

This page allows to select the input of foundation data such as Depth of the Foundation and Embedment.

Depth of Foundation

Enter the overall depth of the foundation.
↔ Range: 0 to 10 m

Embedment Depth Percentage

Enter the percentage depth of embedment of the base block in to the soil.
↔ Range: 0 to 100 %

The buttons   Base Block Details   and   Pedestal Details   are provided in this section.

Base Block Details

Click this button to open the pop-up dialog to define the base block and its dimensions. This is a spreadsheet type input dialog - right click on the spreadsheet to add or delete rows. Alternatively, the user can copy and paste data from an external source such as Microsoft Excel.

Location of Base Block

Enter the location of base block corresponding to X and Y directions from origin.

Dimensions of Base Block

Enter the dimensions of the base block.

Base block in X direction (Lxb)

↔ Range: 0.1 to 100 m

Base block in Y direction (Lyb)

↔ Range: 0.1 to 100 m

Depth of the base block (Lzb)

↔ Range: 0.2 to 10 m

Pedestal Details

Click this button to open the pop-up dialog to define the dimension and location of pedestals. This is a spreadsheet type input dialog - right click on the spreadsheet to add or delete rows. Alternatively, the user can copy and paste data from an external source such as Microsoft Excel.

Dimensions of pedestal

Pedestal dimension in X direction (Lxp)

Enter the pedestal dimension in X direction.
↔ Range: 0 to 100 m

Pedestal dimension in Y direction (Lyp)

Enter the pedestal dimension in Y direction.
↔ Range: 0 to 100 m

Depth of Pedestal (Lzp)

Enter the depth of the pedestal.
↔ Range: 0 to 10 m

Location of Pedestal

Enter the location of pedestal corresponding to X, Y and Z directions from origin.

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Machine and Dynamics

This page allows to provide the machine and dynamics data.

Machine and Dynamics

The buttons   Machine Components   and   Machine Speed   are provided in this section.

Dynamics

The following buttons are provided as a pop-up dialog for the input data:

• Dynamic Loading Points
• Amplitude / Velocity Points
• Dynamic Loads

Machine Components

Click this button to open the pop-up dialog to define the machine components. This is a spreadsheet type input dialog - right click on the spreadsheet to add or delete rows. Alternatively, the user can copy and paste data from an external source such as Microsoft Excel.

Component Description

Enter the name of the machine component such as pump, motor, etc.,

Weight

Enter the weight of the machine component.
↔ Range: 0.1 to 10000 kN

Mass Moment of Inertia of Machine Component

Enter the mass moment of inertia of machine in X, Y and Z directions.
↔ Range: 0 to 10000 kg-m²

Centre of Gravity

Enter the centre of gravity of the machine component corresponding to X, Y and Z directions from origin.

Machine Speed

Click this button to open the pop-up dialog to define the machine speed. This is a spreadsheet type input dialog - right click on the spreadsheet to add or delete rows. Alternatively, the user can copy and paste data from an external source such as Microsoft Excel.

Constant Speed

If the machine is of constant speed type, the speed should be entered in Speed-1. Entering speed data in speed-1 column alone will consider the machine runs in a constant speed.

Variable Speed

If the machine runs at variable speeds, then speed data should be entered in corresponding columns. A maximum of ten speeds for a single machine can be given as an input.
↔ Range: 50 to 25000 RPM

Dynamic Loading Points

Click this button to open the Dynamic Loading Points pop-up dialog. This is a spreadsheet type input dialog but rows cannot be deleted or added. The user can copy and paste the data from an external source such as Microsoft Excel.

Coordinates of Points

Enter the X, Y and Z coordinates from the origin at which the dynamic load is acting.

Used at

Displays the dynamic load which is acting at the corresponding location.

Amplitude / Velocity Points

Click this button to open the Amplitude / Velocity Points pop-up dialog. This is a spreadsheet type input dialog but rows cannot be deleted or added. The user can copy and paste the data from an external source such as Microsoft Excel.

▽ Auto Detect: Amplitude / Velocity points will be auto detected by considering farthest point from the CG of the foundation system.
▽ User Defined: Selecting this option and use popup button to enter Amplitude / Velocity points.

Coordinates of Points

Enter the X, Y and Z coordinates value from the origin at which the amplitude/velocity is to be calculated.

Dynamic Loads

Click this button to open the dynamic loads pop-up dialog. This is a spreadsheet type input dialog but rows cannot be deleted or added. The user can copy and paste the data from an external source such as Microsoft Excel.

Points

List of dynamic loading points defined will be displayed in a drop down box. Select the point at which the corresponding loads are acting.

Forces

Enter the forces acting in the selected loading point in corresponding X, Y and Z directions.
↔ Range: -100000 to 100000 kN

Moment

Enter the moments acting in the selected loading point in corresponding X, Y and Z directions.
↔ Range: -100000 to 100000 kNm

Phase Angle

Select Phase angle (0 or 90 degree) for the Forces and Moments which act in X, Y and Z directions in the corresponding drop down to simulate the cyclic loadings.

Machine Speed

The machine speed defined earlier will be listed as a drop down. Select the machine speed corresponding to the machine type (ie., Constant / Variable Speed) and its location points.

Resonance Modes

▽ All Modes: On Selecting "All Modes", program will consider all of the following as mode of vibration.

• Uncoupled Modes - Translational
• Uncoupled Modes - Rotational
• Coupled Modes

▽ Modes based on Forces: On Selecting "Modes based on Forces", program will consider the modes according to the presence of dynamic loads.

▽ Select Modes: On selecting "Select Modes",   Select Mode   button will be displayed.

Select Modes (Resonance Modes)

Clicking on select mode button will display the Resonance Modes pop-up. This pop-up will display list of all the possible modes of vibration to be considered. Select the modes of vibration which are to be considered for the analysis.

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Non Dynamics

This page allows to define the non-dynamic load cases, loading points and loads.

The following buttons are provided for pop-up dialog for the input data:

• Non-Dynamic Load Cases
• Non-Dynamic Loading Points
• Non-Dynamic Loads

Non-Dynamic Load Cases

Click this button to open the non-dynamic load cases pop-up dialog. This is a spreadsheet type input dialog - right click to add or delete rows. Alternatively, the user can copy and paste the data from external source such as Microsoft Excel.

In this pop-up, n - number of load cases and its Type can be defined.

Description

Enter the description of the load case. While the description can be duplicated across various cases, this is not advised since it is used as a reference to define load combinations. This field cannot be left blank and the special character '#'cannot be used.

Type

Select the load type Dead, Live, Wind, Seismic, Emergency, Maintenance, Abnormal, Operation or Other. First load case type should be always 'Dead'.

Non-Dynamic Loading Points

Click this button to open the Non-Dynamic Loading Points pop-up dialog. This is a spreadsheet type input dialog where rows can be deleted or added. The user can also copy and paste the data from an external source such as Microsoft Excel.

Coordinates of Points

Enter the X, Y and Z coordinates value from the origin at which the non-dynamic loads are acting.

Non-Dynamic Loads

Click this button to open the non-dynamic loads pop-up dialog. This is a spreadsheet type input dialog where rows can be deleted or added. The user can also copy and paste the data from an external source such as Microsoft Excel.

Forces

Enter the forces acting in the selected loading point in corresponding X, Y and Z directions.
↔ Range: -100000 to 100000 kN

Moment

Enter the moments acting in the selected loading point in corresponding X, Y and Z directions.
↔ Range: -100000 to 100000 kNm

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Loads Combinations

This page allows to define the service load combinations with dynamic and non-dynamic loadings and allowable factors for percentage change in safe bearing capacity, overturning and sliding are defined in this page.

The following buttons are provided for the pop-up dialog to input the data.

• Service Load Combinations
• Allowable Bearing and Safety Factors

Service Load Combinations

Click this button to open the Service load Combinations pop-up dialog. This is a spreadsheet type input dialog - right click to add or delete rows. Alternatively, user can copy and paste the data from an external source such as Microsoft Excel.

In this pop-up, n - number of load combinations can be generated by defining different load factors.

Load Cases Factors

Load case descriptions are displayed in each spreadsheet column. This pop-up consists of factors for both dynamic and non-dynamic load cases.
↔ Range: -5 to 5

Allowable Bearing and Safety Factors

Click this button to open the allowable factors pop-up dialog. This is a spreadsheet type input dialog but rows cannot be deleted or added. The user can also copy and paste the data from an external source such as Microsoft Excel.

The first column header displays the service load combination according to the load factors defined in the service load combinations.

SBC Inc/Dec (%):

Enter the percentage of increase / decrease of safe bearing capacity for each service load combination. Negative value indicates decrease in allowable value.
↔ Range: -100 to 200 %

Overturning / Sliding

Enter the allowable factor of safety for the stability checks.
↔ Range: 1 to 10

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Graphical Mode

The base block and the pedestal geometry can also be modelled visually in Graphical Mode. Graphical Edit mode is invoked by clicking the Graphical Mode menu.

Click the base block or pedestal geometry on the picture to select and make the modification using the buttons given on the left side.

Buttons are provided for group selection, copying, rotating the base block and pedestals.

The buttons   L   Left,   R   Right,   B   Bottom and   A   All can be used to pan through the model.

The buttons   Undo  ,   Redo   and   Reset   are used to undo, redo or reset the recent changes.

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Graphical Mode - 3D View

Click on the "3D view" button to display the 3D view of the foundation developed.

Options to edit is not available in 3D view. In order to make a change, use 'Back to 2D View' button.

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Settings

Setting for various Analysis data such as Dynamic criteria, Damping ratios, Soil and Concrete properties, and safety factors are presented in this section. This setting pop-up can be accessed by clicking the bottom panel below the left navigation.

Dynamic Criteria

Enter the permissible limits for no resonance, amplitude, velocity, mass ratio, eccentricity and degree step for time history analysis.

Lower Frequency Limit

↔ Range: 0.1 to 1

Higher Frequency Limit

↔ Range: 1 to 2

Permissible Amplitude

↔ Range: 0.1 to 500 μm

Permissible Velocity

↔ Range: 0.1 to 100 mm/s

Minimum Foundation / Machine Mass Ratio

↔ Range: 1 to 10

Base Eccentricity Limit

↔ Range: 1 to 10 %

Degree Step

Degree step is converted in to time step for Time history analysis.
↔ Range: 1 to 360 deg

Maximum Damping Ratio

Enter the maximum damping ratio in vertical, horizontal and rotational motion in the corresponding directions.

☉ACI 351.3R: Select this option to use Damping ratio as per ACI 351.3R.
☉User Defined: Select this option to enter the maximum damping ratio.

Motion in Vertical (Z Direction)

↔ Range: 0.01 to 0.5

Motion in Horizontal (X & Y Direction)

↔ Range: 0.01 to 0.5

Rotational Motion (Mx)

↔ Range: 0.01 to 0.5

Rotational Motion (My)

↔ Range: 0.01 to 0.5

Rotational Motion (Mz)

↔ Range: 0.01 to 0.5

Properties

Enter the properties of materials such as soil and concrete in this properties pop-up dialog.

☉Dynamic Shear Modulus: Dynamic shear modulus is applicable for Richard - Lysmer method. If user enters this value in Barkan's method, the program will convert dynamic shear modulus into uniform compression.
↔ Range: 10000 to 500000 kN/m²

☉Uniform Compression: Dynamic shear modulus is applicable for Barkan's method. If user enters this value in Richard - Lysmer's method, the program will convert uniform compression into dynamic shear modulus.
↔ Range: 500 to 75000 kN/m³

Allowable Net Bearing Pressure

↔ Range: 25 to 1000 kN/m²

Coefficient of Uniform Compression

↔ Range: 500 to 75000 kN/m³

Density of Concrete / Soil

↔ Range: 10 to 40 kN/m³

Ground Water Table depth Below ground

↔ Range: 0 to 10 m

Coefficient of Friction

↔ Range: 0.05 to 1.5

Poisson's Ratio

↔ Range: 0.2 to 1

Factor of Safety

Enter the factor of safety against sliding and overturning in this pop-up.

F.O.S against Sliding / Overturning

↔ Range: 1 to 5

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Error Handling

Errors and Warnings are generated to prevent any inadvertent error in the input data. This section describes how to handle the errors and warnings. These errors are displayed at the bottom of the input page when the data in one or more input fields invalidate each other.