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[CIM/Rebar] Reinforcement Method using Void Object


How do you work with complex rebar like tendon rebar?



Various types of reinforcement are possible by using the Void object.



This document describes how to use the Void object for reinforcing reinforcement.
A Void object is a 3D structure whose Member Type is set to Void, and has characteristics that are excluded from drawing, analysis, and quantity functions.
(For more information on Member Type, refer to the manual : Member Type Properies)

CIM proceeds with rebar modeling by referring to points and lines of objects.
In order to model the reinforcing bars that do not follow the original object, you can create a separate void object for easier rebar modeling.
In this case, modeling using the void object allows the user to perform rebar modeling in the desired shape.
We will explain the rebar modeling method using the void object through three examples.

A. Tendon Rebar B. Main Reinforcing Bars and Band Reinforcing Bars in the Column Part
C. Rebar in the Opening  

A. Modeling of Tendon Rebar using Void Object

Figure 1. Tendon Rebar

For tendon rebar of SC girder or box girder, rebar is placed along the tendon path regardless of the structure.

The above image is an example of using a rectangular void object that follows the tendon path when reinforcing a rectangular burst rebar.

Even when the tendon profile is modified, the reinforcement can be easily adjusted only by adjusting the void object.

In the above situation, the user can proceed with rebar modeling by creating a void object that fits the desired shape.

Example In Figure 1., a void object with a rectangular cross section was created to model a rectangular reinforcing bar. Reinforcement was carried out inside the void object.

B. Modeling of Column Reinforcement Using Void Objects

In the case of reinforcing bars in the column part, the arrangement of the reinforcing bars must proceed to the coping and the foundation, which is outside of the column member to be reinforced.

CIM has the characteristic of setting the Draw Plane between rebar modeling and arranging rebars in only one direction.

Therefore, when modeling without a void object, additional work is required to arrange the reinforcing bars inside the column to the outside of the column.

To reduce the need for such additional work, and to make it easier to modify and edit by recognizing it as a single reinforcing bar, you can utilize the Void object.

That is, as in the example below, the difference in shape between the section where the reinforcing bars are to be arranged and the object is resolved through the void object.

In the case of pier column reinforcement modeling, void objects are created up to the foundation and coping where the actual band and longitudinal reinforcement are to be arranged.

The method of modeling column reinforcing bars using void objects is as follows.

Figure 2. Create a void object that connects to the coping and the foundation with
the same cross section as the column

In the case of the main reinforcing bar of a column, the reinforcement is carried out by referring to the cross section of the column. Rebar arrangement is difficult.

To complement general rebar modeling (left) where rebars are not arranged in the opposite direction to which Draw Plane is set, If you create a void object to the position where you want to arrange the reinforcement (right), you can proceed with modeling the column reinforcement until coping.

Figure 3. Proceed with reinforcement and arrangement of void objects

Figure 4. Parameter shape conversion response

As shown in Figure 5., if you use the Multi-Point/Parameter function along with the Void object, not only the height of the column, but also Rebar arrangement can be maintained in response to changes in the thickness of foundations and copings.
(If you need additional explanation about Multi-Point function, please refer to the following manual: Multi-Points Linked Entity)

If the reinforcing bar needs to change in response to the shape change of a specific object, set the parameter between the void object and the object.

You can set it to be able to respond automatically.

C. Rebar in the Opening

Figure 6. Movement and deformation of the opening

The modeling of the opening rebar can be created by applying the aforementioned cutting function and the void object.

The modeling method of opening rebar using the cutting function and void object is as follows.

① Create Void Object
Create a void object as much as the area corresponding to the opening above the general wall shape.

② Reinforcement with Reference to the Void Object Reinforce the void object.


③ Application of Target & Tool of Cutting Function



Using the Cutting function, apply the wall as the target and the opening as the tool.


After applying the cutting function, the same shape can be realized even if reinforcement is performed at the wall section instead of through the opening.
However, the opening rebar must correspond to the position or size of the opening, but when modeling directly on the wall, it does not respond to the movement or size change of the opening.
In case of reinforcing the void object (opening), when the void object is moved or the section of the opening is changed later, reinforcing bars are also available, so reinforcement is carried out on the void object.

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