Civil Engineering/Linked Elements


Hello, this is a follow-up of my previous question. A case I'm having is to model a bridge connecting 2 towers with end connectivities "hinged-roller", and this can't be done by application of release option (in case of using beams to represent bridge slab).

So I've been told to use linked elements, in which you define a link property in which you input a certain value of stiffness in the direction you wish to apply restriction.

Then you can assign that link property to a frame section, for example columns. By using link property, a hinge or roller ( depending on the directions you've restricted) is created at the top end of the column.

I asked if I could apply release to the column instead of using linked elements, but the answer was NO since this will create extra moment. So I'm somehow obliged to use this method.

Hope this info helps :) Thanks !!

Hi Mohammad,

I don't think you need to use Linked elements, as you can easily so the end-releases for the frame section (beams of bridges) as noted below in the ETABS Help menu.

Any of the three translational and three rotational degrees of freedom can be released at either end of a line object. However, the releases are meaningful only if a frame section property has been assigned to the line object. It is possible to specify partial fixity at the ends of the line object. This is accomplished by specifying a spring stiffness when you assign the member end release as described herein.

The releases are always specified in the line object (frame section) local coordinate system. End releases are always assumed to occur at the support faces, that is, at the inside end of the end offset.

Select the line object(s) to which end releases or partial fixity are to be assigned.

Click the Assign menu > Frame/Line > Frame Releases/Partial Fixity command to open the Assign Frame Releases form

On the Assign Frame Releases form

Specify the desired end releases by checking the appropriate check boxes.

Alternatively, specify partial fixity by entering a spring stiffness value for the frame partial fixity springs.

Click the OK button.

If you want to remove all of the currently specified end releases, including partial fixity, from a member, check the No Releases check box at the bottom of the form and click the OK button.


Make sure you do not do releases at both ends or in combinations that lead to instability- see the rest of the item in the Help menu.

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Arshad Khan


I can answer any questions to do with civil and structural engineering consultancy and construction industry in East Africa and the Middle East, and specifically with the analysis and design of reinforced concrete structures. My particular expertise is in the aseismic design and optimisation of tall buildings.


Employment history: 40 years in Construction and consultancy in the UK, Kenya, Tanzania, Uganda, Ethiopia, Eritrea, South Africa, Somalia, Zambia, Austria, Bahrain, Kuwait, Doha and the U.A.E.

.Fellow of Institution of Structural Engineers (UK) .Fellow of Institution of Civil Engineers(UK) .Member of the Institution of Engineers, Kenya .Registered Engineer, ERB, Kenya .Member of the Architectural Association of Kenya (Engineers Chapter) .Chartered Engineer (UK)

•1984: International Conference on the Art and Practice of Structural Design, London •1994: 3rd Int. Kerensky Conference in Structural Engineering, Singapore •2008: International Conference on High-Rise Towers, Abu Dhabi •2013: IEK International Conference, Kisumu, Kenya

BSc, 1st Class Hons, in Building Engineering, University of Bath, UK MSc in Concrete Structures and Technology, University of London. Diploma of Imperial College, UK.

Awards and Honors
•Science Congress Special Award (for 2-seater Hovercraft - 1968) •Institution of Civil Engineers Award for outstanding performance at Bath University (1975) •Concrete Society Postgraduate study Bursary Award (1976) •Consular Representative for British High Commission, Nairobi. (1995 to 1998) •Examiner for Institution of Civil Engineers Professional Interviews, Nairobi. (1997 to 1998) •Branch Representative in Vienna for PI assessment for Inst. of Struct. Engrs. (1999 to 2010)

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