Ledge

This tab covers both the parameters and the results used in the analysis of ledges.  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.

Dimensions

The dimensions of the ledge and supporting member (spandrel or IT beam) 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.

 Section Type: The user can select between using either a spandrel or an inverted tee beam as the supporting member.  Note that if you have an L-beam you should use the spandrel option.

 Web Width: Width of the web of the supporting member

 Member Height: Overall height of the supporting member.

 Ledge Height (L/R): Height of the ledge.  Note that for inverted tees, you have the option of different height ledges between the left and right sides of the beam (left and right are defined on the 2D sketch).

 Ledge Projection (L/R): Distance between the outer face of the ledge and the face of the web of the supporting member.  Note that for inverted tees, you have the option of different ledge projections between the left and right sides of the beam (left and right are defined on the 2D sketch).

Ledge Loads

 Loads are closely spaced or uniform loads: Select this option of the loads are relatively uniform (as with flat slabs bearing on the ledge).

 s: If the loads are not closely spaced or uniform, then you will need to input the spacing.

 b_t: If the loads are not closely spaced or uniform, then you will need to input the width of the load on the ledge.

 d_e: Distance from the end of the member to the first load.

 V_u (L/R): Factored vertical applied point load.

 e (L/R): Eccentricity of the load as measured from the face of the web of the supporting member.

 N_u (L/R): Factored horizontal applied load (if any).

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).

f_y: Yield strength of the rebar.

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.

Use μ value for μe: If this box is checked the μ value input in this section will be used for μe.

Member Performance

R Calculation method: If you select user defined, you will need to input an R value.  If calculated, you will need to input several parameters used by the program to calculate R.

R: You will need to assign an R value if the calculation method for R is User Defined.

Reinforcement

This section is not available in Auto Design mode.

 A_s size/Spacing: The As steel is the main reinforcement that is used to resist the flexure in the ledge.  The user can set the bar size and quantity of bars here.

Utilization Summary

Multiple utilizations (the ratio between applied vs. capacity) are calculated by the program and listed here.  In Manual Design mode, a green check mark or red X is also displayed where appropriate.

Attachment of Ledge to Web

Hanger steel which is used in tension to hold the ledge to the beam is checked here.