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{live-template:Test Problem}

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Default modeling procedures locate object boundary conditions along the centroid of the cross section. When a simply supported (pin-pin) [frame|kb:Frame] object is modeled with a top-center or bottom-center *insertion point*, internal [constraints|kb:constraint] are generated which have the effect of a vertical offset. A kinematic result of this modeling technique is the generation of longitudinal forces which act on an arm about the neutral axis. If this behavior is not desired, one support may be changed from a pin to a roller condition such that horizontal reactions are released. This behavior may be exhibited when [bridge objects|kb:Bridge Modeler] are supported by [bearing links|kb:link] located at the bottom of the bridge girders.

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Presented in Figure 1 are visuals which depict how standard and offset objects:

* Are displayed in the software interface.

* Are kinematically related to the analytical model.

* Respond under flexural loading.

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!fig 1 - pined beam with top center and bottom center insertion points.png|align=center,border=1!

{center-text}Figure 1 - Simply-supported beam with center and bottom-center insertion points{center-text}

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The images from Figure 1, as they appear in [SAP2000|sap2000:home], are given in Figure 2:

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!fig 2 - general view, reactions and moments.png|align=center,border=1!

{center-text}Figure 2 - Images as they appear in SAP2000{center-text}


h1. See Also


* [Nonzero moment at abutment locations|kb:Nonzero moment at abutment locations] article

* [Verification Example 1-011|doc:Verification examples]


h1. Attachments

* [SAP2000 V14.2.3 model |Effect of insertion point on beam reactions^model A V14.2.3.zip] (zipped SDB file)