ECCOLUMN - Reinforced Concrete Column Design

This part of user manual describes how to use ECCOLUMN for the design of Reinforced Concrete Column. 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 a basic understanding of foundation design concepts.
The minimum input data required to use this application is as follows:

• ❶ Slenderness Conditions
• ❷ Loads and Moments at Top and Bottom
• ❸ Allowable safety factors
• ❹ Material Properties

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

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Dimensions

This page allows to select the dimensions of the concrete column.

Rectangular Column

Column Cross section

☉Rectangle: Select this option to design a rectangular column.
☉Circle: Select this option to design a circular column.
☉Octagon: Select this option to design a octagon column.

Section Width - b

Enter the width of the rectangular concrete column.
↔ Range: 120 to 2000 mm

Section Depth - h

Enter the depth of the rectangular concrete column.
↔ Range: 120 to 2000 mm

Circular Column

Section Diameter - h

Enter the diameter of the circular concrete column.
↔ Range: 120 to 2000 mm

Octagonal Column

Edge Length - a

Enter the edge length of the octagon.
↔ Range: 120 to 2000 mm

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Slenderness

This page allows to select the slenderness properties of the column section.

Short Column

☉Short Column: Select this option to design column as short column.
☉Long Column: Select this option to design column as long column.

☐  Check Minimum Eccentricity
Select this option to consider minimum eccentricity check in the design.

Long Column

In case of long column, user has to provide the following information.

Column Clear Height - I_o

Enter the overall height of the column.
↔ Range: 1000 to 20000 mm

Effective Length Factor about Z Axis - β_z

Enter effective length factor about Z axis or choose the effective factor from table.
↔ Range: 0.3 to 4

Effective Length Factor about Y Axis - β_y

Enter effective length factor about Y axis or choose the effective factor from table.
↔ Range: 0.3 to 4

Slenderness

Clicking on popup button of effective length factor about Z axis or y axis, will open the slenderness popup.

Effective Length Factor about Z Axis - British

Displays the effective length factor about Z axis value based on the selection.

Type of Slenderness

Select the type of slenderness from the drop down.
▽ Braced: Select this option to design the column as a braced member.
▽ Unbraced: Select this option to design the column as a unbraced member.

End1 / End2

▽ d ≥ h: The end of the column is connected monolithically to beams on either side which are at least as deep as the overall dimension of the column in the plane considered. Where the column is connected to a foundation structure, this should be of a form specifically designed to carry moment.
▽ d < h: The end of the column is connected monolithically to beams or slabs on either side which are shallower than the overall dimension of the column in the plane considered.
▽ Tie Beam: The end of the column is connected to members which, while not specifically designed to provide restraint to rotation of the column will, nevertheless, provide some nominal restraint.
▽ Free: The end of the column is unrestrained against both lateral movement and rotation.

Effective Length Factor about Z Axis - European

Displays the effective length factor about Z axis value based on the selection.

Type of Slenderness

Select the type of slenderness from the drop down.
▽ Braced: Select this option to design the column as a braced member.
▽ Unbraced: Select this option to design the column as a unbraced member.

End1 (Braced)

▽ Both ends no rotational restraint
▽ End 1 no rotational restraint, End 2 rotational restraint
▽ Both ends rotational restraint

End1 (Unbraced)

▽ Top free, bottom rotational restraint (Cantilever)
▽ Both ends rotational restraint

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Cover

This page allows to select cover details for reinforcement.

Clear Cover - C_c

Enter the clear cover for reinforcement, if Column Design Option is selected as Check Reinforcement Adequacy.
↔ Range: 15 to 85 mm

Effective Cover

Enter the effective cover for reinforcement, if Column Design Option is selected as Find Required Reinforcement.
↔ Range: 15 to 150 mm

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Main - Check Reinforcement Adequacy

This page allows to select main reinforcement details, if Column Design Option is selected as Check Reinforcement Adequacy. In this method, moment carrying capacity of the section will be calculated based on the loads and reinforcement details provided.

Main Reinforcement - Rectangular Column

Provided Reinforcement

Shows the area of reinforcement provided based on the rebar configuration.

Corner Bars

Corner bars are fixed to 4 numbers.

Dia

Enter or choose the diameter for corner bars.
↔ Range: 4 to 60 mm

Additional Rebars(each face)

Provide the number of bars and diameter for width and depth bars.

Diameter of Bar

↔ Range: 4 to 60 mm

Main Reinforcement - Circular Column

Provided Reinforcement

Shows the area of reinforcement provided based on the rebar configuration.

No of Bars

Choose the number of main reinforcement bars.
↔ Range: 6 to 15 Nos

Bar diameter

Enter or choose the diameter of main reinforcement.
↔ Range: 4 to 60 mm

Main Reinforcement - Octagon Column

Provided Reinforcement

Shows the area of reinforcement provided based on the rebar configuration.

Corner Bars

Corner bars are fixed to 8 numbers.

Diameter of Bar

Enter or choose the diameter of main reinforcement.
↔ Range: 4 to 60 mm

Additional Rebars(each face)

Enter or choose number of bars and diameter for width bar.

Main - Find Required Reinforcement

This page allows to select the arrangement of main reinforcement in the column section, if Column Design Option is selected as Find Required Reinforcement. In this method, area of reinforcement required will be calculated.

☉Equally distributed: Main reinforcement will be equally distributed over the section for the design.
☉Proportionately distributed: Main reinforcement will be proportionately distributed over the section for the design.

Circular Section

No of Bars

Select the number of bars from the drop down menu.

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Shear - Check Reinforcement Adequacy

This page allows to select shear reinforcement details.

Shear Reinforcement - Rectangular Column

Diameter of Shear Reinforcement - D_s

Enter or choose the diameter of the shear reinforcement.
↔ Range: 4 to 60 mm

Spacing between Stirrups - L_s

Enter the spacing between shear reinforcement.
↔ Range: 20 to 300 mm

Additional Legs in Z Direction - N_z

Select the number of additional legs to be added in z direction.

Additional Legs in Y Direction - N_y

Select the number of additional legs to be added in y direction.

Shear Reinforcement - Circular / Octagonal Column

Diameter of Shear Reinforcement - D_s

Enter or choose the diameter of shear reinforcement.
↔ Range: 4 to 60 mm

Spacing between Stirrups - L_s

Enter the spacing between the stirrups.
↔ Range: 20 to 300 mm

Shear - Find Required Reinforcement

This page allows to select shear reinforcement details, if Column Design Option is selected as Find Required Reinforcement.

Shear reinforcement details will be applicable in "Check Reinforcement Adequacy" option only.

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Design Loads

This page allows to enter design loads. Design loads are entered in an tabular format. This is the menu where we can enter maximum of two combinations for section design.

Design Axial Load - N

Enter the design axial load. Positive value indicates compression.
↔ Range: -10000 to 10000 kN

Bottom Moment about Z Direction - M_zt

Enter the moment at bottom in z direction.
↔ Range: -10000 to 10000 kNm

Top Moment about Z Direction - M_zt

Enter the moment at top in z direction.
↔ Range: -10000 to 10000 kNm

Bottom Moment about Y Direction - M_yt

Enter the moment at bottom in y direction.
↔ Range: -10000 to 10000 kNm

Top Moment about Y Direction - M_yt

Enter the moment at top in y direction.
↔ Range: -10000 to 10000 kNm

Design Shear Force - V_z

Enter design shear force in z direction.
↔ Range: -5000 to 5000 kN

Design Shear Force - V_y

Enter design shear force in y direction.
↔ Range: -5000 to 5000 kN

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Design Setting

Setting for various Design Data such as Concrete, Reinforcement and Partial Safety Factors are presented in this section. This setting pop-up can be accessed by clicking the bottom panel below the left navigation.

Materials - British

Concrete Grade - f_cu

↔ Range: 15 to 100 N/mm²

Main / Shear Reinforcement Grade - f_y / f_yv

↔ Range: 200 to 600 N/mm²

Steel Elastic Modulus - E_s

↔ Range: 100000 to 300000

Materials - European

Compressive Cylindrical Strength

↔ Range: 15 to 100 N/mm²

Main / Secondary Reinforcement Grade

↔ Range: 200 to 600 N/mm²

Modulus of Elasticity of Steel

↔ Range: 100000 to 300000

Material Partial Safety Factor - British

Concrete in Shear / Concrete in Compression / Reinforcement
γ_mcs, γ_mc, γ_ms

↔ Range: 1 to 3

Partial Safety Factor - European

Concrete / Reinforcement

↔ Range: 1 to 3

Column Design Option

☉Check Reinforcement Adequacy: Select this option for known rebar configuration of the section, hence the program will check the moment.

☉Find Required Reinforcement: Select this option for unknown rebar configuration, hence the program will find the area of reinforcement required for the section.

National Annex - European

This popup allows to select options for national annex in case of European Standard.

Nation

Select the nation based on which the coefficient value to be considered. The available standards are Recommended, UK, Finland, Ireland, Malaysia, Norway, Singapore, Sweden and User Defined.

User Defined

Select this option to enter the coefficient values.

α_cc

↔ Range: 0.7 to 1.2

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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.