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h1. Question

IFiber havehinges aseem technicalto questionintroduce regardingartificial the correct use of fiber hinge elements in the SAP2000 program. I believe that other hinges (for example moment hinges or shear hinges) have a rigid-plastic behavior.  Placing these hinges in a model composed of frame elementsflexibility to the model, though hinges should not alter theinfluence elastic stiffness of the modelbehavior. However,Is it ispossible myto understanding that the SAP implement fiber hingehinges has an elastic stiffness, based on without the materialintroduction properties.of Sincesoftening?
it
occurs at a point, but computes hinge demands based on a hinge length provided by the user, I find that it introduces "artificial" flexibility to my model. By this I mean that if I defined a single degree of freedom cantilever column and computed its stiffness without any hinges, the period would be shorter than an identical model with a fiber hinge with identical material properties.

Can you help me to understand how to implement the use
h1. Answer

This softening behavior may be attributed to calculation of the SAP2000 fiber hinge without introducing additional flexibility into my model?

h1. Answer

The reason you are noticing this softening is because the fiber hinges -hinge response curve, iswhich calculatedproceeds directly from the axial response of individual section fibers. and the elasticity in the During linear rangeresponse, offiber the hingeelasticity is added to theelement elasticity, ofcausing the elementsoftening. To avoid this softeningbehavior, youusers should discretize the memberdivide [frame|kb:Frame] members at hinge locations (dividesuch the frames to create that a smallsmaller elementsegment withis apositioned lengthalong equals to the hinge length). and assignA a large area property modifier to theshould then be assigned to small sections by, using the Assign>Frame>Property modifiers Assign > Frame > Property Modifiers menu.
command.

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Related Incident 27945.
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