# Approach Slab \[TB]

For modeled abutments, approach slabs can be modeled as a separate object using this object of the workflow.

## General

**Abutment:** This parameter specifies the abutment for which the approach slab will be modeled.

**Logitudinal Offset:** The offset value for the approach slab in the longitudinal direction can be specified using this parameter. Approach slabs are generated at the location where the chosen abutment's abutment wall starts. A negative value offsets the approach slab in the downstation direction; a positive value offsets it upstation.

**Transverse Offset:** Offset of the approach slab transverse to the PGL (perpendicular to the bridge alignment). Defaults to the abutment's transverse offset. Positive values shift the slab to the right when looking upstation.

**Material:** A material can be assigned to the approach slab from either previously defined options under Properties-Materials or imported as needed.

**Start Skew:** The skew angle at the start of the approach slab (the downstation section) can be defined using this parameter.

**End Skew:** The skew angle at the end of the approach slab (the upstation section) can be defined using this parameter.

**Length:** The length of the approach slab in the longitudinal direction can be specified using this parameter. For a visual representation, refer to the figure provided below.

**Width:** The width of the approach slab in the transverse direction can be specified using this parameter. For a visual representation, refer to the figure provided below.

**Second Width:** This parameter specifies the width in the transverse direction for the portion of the approach slab that extends beyond the wing wall length.

**Secondary Slab Width Extension:** Additional width added to the approach slab outside the primary slab width — used when the approach slab extends past the main deck edge in the transverse direction.

**Barrier Region Width Left:** Width of the left-hand barrier region on the approach slab (measured in the transverse direction). Used to exclude the barrier-covered portion from the driving surface area.

**Barrier Region Width Right:** Width of the right-hand barrier region on the approach slab (measured in the transverse direction).

**Thickness:** The thickness of the approach slab can be defined using this parameter. For a visual representation, refer to the figure provided below.

**Gap Between End of Left Wing Wall:** This parameter defines the gap between the approach slab and the left wing wall of the abutment.

**Gap Between End of Right Wing Wall:** This parameter defines the gap between the approach slab and the right wing wall of the abutment.

![image-20250115-132839.png](https://openbrim.atlassian.net/wiki/download/attachments/2847277213/image-20250115-132839.png?api=v2)

## IFC

**Type:** The IFC entity type for BIM export. Options include IfcSlab and other standard IFC element types.

**Predefined Type:** The IFC Predefined Type is specified using this parameter. Available options include:

* APPROACH\_SLAB (default)
* BASESLAB
* FLOOR
* LANDING
* PAVING
* ROOF
* SIDEWALK
* TRACKSLAB
* WEARING
* USERDEFINED
* NOTDEFINED

**Parent \[Bridge/Superstructure/Deck/Substructure/Foundation/Approach\_Structure/Retaining\_Structure]:** The IFC Parent is specified using this parameter to define the hierarchy relationship in the IFC model.

## Quantities

**Rebar Density(per cubic yard):** The density of reinforcing steel per cubic yard of concrete. Used to calculate the rebar weight based on the approach slab volume.

**Rebar Weight:** The calculated rebar weight based on the rebar density and approach slab volume. (Read-only)

**Volume:** Based on the definitions provided by the user, the volume of the object is calculated and presented in this column. (Read-only)

**Weight:** The total weight of the approach slab based on volume and material density. (Read-only)

## Referencing Objects

**Sleeper Slabs:** Sleeper Slab workflow items that reference this approach slab. (Read-only)


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