Corbel
- Becca Alford (Unlicensed)
This tab covers both the parameters and the results used in the analysis of corbels. All input parameters and results should fit on one printed page. Note that both the 2D sketch contained within the input (and therefore printed in the output), and the 3D model are updated in real time as you change the design parameters.
Program Operation
Select either Manual Design or Auto Design. Manual Design allows the user to input the reinforcement. Auto Design calculates the required area of the reinforcement for the user.
Project Information
Project: Project name.
Location: Location of the project.
Date: Date printed on the report (defaults to the current date).
Client: Name of the client.
Designer: Name of the design engineer.
Job Number: Job number for the project.
Description: Long form description for the project.
Material Properties
The material properties section contains input for both the concrete and the reinforcement, along with various material and friction factors.
f’c: Final compressive strength of the concrete (often referred to as the 28-day strength).
fy: Yield strength of the rebar.
φ factor: The φ factor is a resistance factor applied to the yield strength of the reinforcement. A value of 0.75 is recommended.
μ factor: The μ factor is a shear-friction coefficient based on the crack interface condition. Typical values are 1.4 for monolithic corbels and 1.0 for non-monolithic corbels.
λ factor: The λ factor is a material reduction factor based on the density of the concrete. Typical values are 1.0 for normal weight concrete and 0.75 to 0.85 for lightweight concrete. It is used in the calculation of the effective shear-friction coefficient.
Use μ value for μe: The shear-friction coefficient used in the calculations can be set to either μ or μe. If this box is checked the shear-friction coefficient will be set equal to the assigned μ, otherwise μe will be used as the coefficient.
Loading
Vu: Factored vertical applied point load.
Nu: Factored horizontal applied load (if any).
Dimensions
The dimensions of the corbel in this section are shown in the dynamic, scaled 2D sketch to the right, and will be highlighted when the cursor is in the accompanying text box for that dimension.
Corbel height: Height of the corbel measured from the top of the bearing surface to where the bottom of the corbel intersects the face of the supporting column.
Member thickness: Thickness is measured from the face of the supporting member where the corbel is attached to the back face.
Corbel length: Distance from the face of the supporting member where the corbel is attached to the outermost face of the corbel.
Corbel width: Width of the corbel perpendicular to the face of the supporting member. Note that this dimension is not shown in the 2D sketch.
Tapered height: Height of the taper (if any) of the corbel. Note that this value can be zero.
Load location: Location of the vertical load (Vu) measured from the face of the supporting member where the corbel is attached..
Front cover: This is distance from the outermost face of the corbel to the start of the main reinforcement.
Back cover: The back covert is measured from the back face of the supporting member to the edge of the vertical leg of the main reinforcement.
Top cover: This value is used to calculate the distance d between the center of the main reinforcement to the extreme compression fiber. Note that this dimension is not shown in the 2D sketch.
Reinforcement
This section is not available in Auto Design mode.
As size/Quantity: The As steel is the main reinforcement that is used to resist the flexure in the corbel. The user can set the bar size and quantity of bars here.
Ah size/Quantity: The Ah steel is used to resist the shear at the face of the supporting member. The user can set the bar size and quantity of bars here.
Framing bar size: This bar is used for informational purposes only, it is not used in the analysis.
Analysis Notes
Reinforcement Limits: Various code and handbook reinforcement limits are checked here for conformance. In Manual Design mode, a green check mark or red X is also displayed where appropriate.
Ultimate Capacity: In Manual Design mode, the ultimate capacity (φVn) is displayed along with the ratio of φVn/Vu (Utilization).
Dimensional Limits: Similar to Reinforcement Limits, various code dimensional limits are checked here for conformance. A green check mark or red X is also displayed where appropriate.
Hooked Bars: Various computed parameters of the main reinforcement that are used in the analysis are displayed here for the user’s information.
Design Limits: Additional code limits are also checked, and the results of these checks are displayed here, along with either a green check mark or a red X.