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This page is devoted to frequently asked questions (FAQ) related to links.

On this page:

Table of Contents

Modeling

Does changing

...

link length affect results?

Answer: The only difference which results from changing link length is an additional moment which results from shear acting over the increased length. Likewise, changing the specification of length location of the for shear deformation (defined by specifying a distance from J end) may change the link response as because this parameter has impact on the correlates with internal link deformationsdeformation. Please note that the link deformations occur deformation occurs at a single location specified by shear deformation location. Please refer to on the Link Definition menu by the value Shear Distance from End J. The equations used to calculate link deformation are available in the CSI Analysis Reference Manual, Chapter (The Link/Support Element , > Section Internal Deformations for the equations used to calculate link deformations, page 238). Changing link length does not affect link stiffness since this value is based on the total force or moment.

Which link property is

...

most suitable

...

for modeling reinforced-concrete shear behavior

...

?

MultiAnswer: The multi-linear plastic-link property, with pivot hysteresis type, would be most suited to model suitable for modeling the shear behavior of reinforced-concrete members.

Should I use a hinge or

...

''See "Comparision of hinges and links" page.

Link Directional Properties

There are the following three main options when you define link directional properties:

  • You leave the Direction unchecked (as is the case for U1 in the screenshot below) - then the link will not contribute any stiffness for the given direction.

...

a link?

Answer: For response, please see the Hinge and link comparison article.

How is friction modeled between two surfaces?

Answer: We recommend using nonlinear link/support elements to model friction behavior between two surfaces. The friction isolator is best for SAP2000 models, and the Isolator 2 is best for ETABS models.

Use engineering judgement when deciding upon linear and nonlinear stiffness properties.


Show if
groupeditors

Related Incidents:

  • Incident 48467: ETABS/ SAP - partial fixity- (Coefficient of friction)

Formulation

What are the Link Directional Properties?

Answer: Three options are available when defining Link Directional Properties. Their descriptions are given as follows:

  1. Leave the Direction option unchecked, as shown in Figure 1 with U1. This will keep the link from contributing stiffness to the direction specified.

  2. Select the Direction and Fixed option, as shown with U2. In this case, the link will not experience any deformation in the

...

  1. direction specified because relatively large stiffness will be applied to that component.

  2. Select the Direction and Nonlinear option, as shown with U3. Here, the link will contribute the stiffness specified when Modify/Show is selected from below the Properties heading.


Image Modified

Figure 1 - Link directional properties

How

...

is link stiffness

...

calculated?

There are various types of links available in the program and you can define their force deformation relationship (for axialAnswer: For the various link objects available, force-deformation relationships may be defined along each degree-of-freedom (DOF), including axial, torsional, major and minor shear, torsion, and major and minor pure bending DOFs) to represent bending. These properties may be specified to simulate the behavior of the structural component (such as bearing, isolator, soil spring, etc.) that is being modeled by the link.Please review desired of bearings, isolators, soil springs, and other structural components modeled using link objects.

The CSI Analysis Reference Manual, chapter " (The Link/Support Element - Basic ", sections "> Internal Deformations " and " Link/Support Properties" for , pages 238 and 240) provides additional details on link internal deformations, force-deformation relationship relationships and internal link internal deformation and forces. You may also find it useful to review the The Derivation of link equations page article may also be useful.

Reporting

How can I plot force-displacement hysteresis

...

for

...

isolators?

Extended Question: How do I get output force-displacement hysteresis curve for isolator? I was trying to see under Display/Show plot function but I couldn’t figure it out force vs. displacement only I found time vs. displacement.

Answer:

See plotting link hysteresis curve pageAnswer: For response, please see the Plotting link hysteresis article.

What are the units for link effective damping?

Answer: For all link properties, the damping input is the actual damping, given in units of Force-SecSecond/Length (i.e. , or Force/Velocity).