Dap
- Becca Alford (Unlicensed)
Analytics
This tab covers both the parameters and the results used in the analysis of daps. 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 dap 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.
Thin-stemmed member: Check this flag if the dapped member is considered to be a ‘thin stemmed member’.
Section height: Overall height of the section being dapped.
Recess height: Height of the dap measured from the bottom of the overall section to the bottom face of the bearing plate.
Recess length: Horizontal distance from the end of the member to the start of the recess at the bearing
Bot. leg width: Width of the dapped member at the bottommost point of the member. Note that this dimension is not shown on the 2D sketch.
Top leg width: Width of the dapped member at the topmost point of the member – are we including decks or composite topping in this calculation, then the top leg width means something different Note that this dimension is not shown on the 2D sketch.
Flange Thickness: Set this value to zero if the member has no flange, or you do not want to consider the flange for this calculation. Otherwise, set this value to the height of the flange.
Flange held back: Check this flag if you are designing a double tee dap and the deck is being held back (typically done when the double tee leg is bearing on a pocket).
Loading
Vu: Factored vertical applied point load.
Nu: Factored horizontal applied load (if any).
Ecc.: The eccentricity of the applied vertical load as measured from the reentrant corner to the assumed location of the applied load.
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.
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.
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.
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.
Reinforcement
Inputs in this section are dependent on the selected mode – Auto or Manual.
Reinforcement schematic: The reinforcement schematic is based on the different types listed in the PCI Design Handbook. These schematics refer to the shape of the vertical reinforcement (Ash) that resist the diagonal tension crack that begins at the reentrant corner of the dap. Note that mesh reinforced and vertical CZ schematics are not supported at this time.
Note: the following reinforcement parameters are only available in Manual Design mode.
As size/Quantity: This reinforcement is used to resist the flexure and axial tension in the extended, in a manner similar to that of the main reinforcement in corbels.
Ah size/Quantity: This reinforcement is used to resist the potential vertical crack extending upward from the reentrant corner, which is resisted by a combination of As and Ah. Note that this bar is not required for the inclined L reinforcement schematic.
Av size/Quantity: This additional reinforcement is required to resist the diagonal tension in the extended end.
Ash size/Quantity: This reinforcement is used to resist the diagonal tension crack which starts from the reentrant corner.
Analysis Notes
Utilization Summary: 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.
Diagonal Tension in Extended End: In Manual Design mode, the ultimate capacity (φVn) is displayed along with the ratio of φVn/Vu (Utilization).
Direct Shear: 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.
Diagonal Tension at Reentrant Corner: Various computed parameters of the main reinforcement that are used in the analysis are displayed here for the user’s information.
Flexure & Axial Tension: 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.