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Verification Example 07

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Vassilis Papanikolaou edited this page Jan 13, 2020 · 1 revision

Eigenvalue analysis of a 3D frame with rigid floor diaphragm

Download Example 7 model (v2.7.0)

Description

A two-story, two- bay, three-dimensional frame structure is analyzed for its four natural periods. The structure is doubly symmetric in plan, except that the center of mass at each story level is eccentric, as shown in the figure below. The entire story mass is applied at these joints in the X and Y directions only.

The GiD+OpenSees results are compared with Seismostruct results. The FE model lies in the X-Y-Z space.

Geometry and Properties

Material Properties:

E = 16.757256 GPa (column)

E = 23.938937 GPa (beam)

Column Properties:

A = 0.3716 m2

I22 = I33 = 0.010789 m4

Beam Properties:

A = 0.4645 m2

I22 = 0.02253 m4

I33 = 0.01381 m4

Modeling and Loading

A lumped mass is applied to joints 28 and 29 with a value of 90.64111 ton in the X and Y directions. Two rigid diaphragm constraints are introduced (one at each floor level). All the base nodes are fully restrained.

The FE model is presented below:

Analysis Type

Eigenvalue analysis

Results and Comparison

The most significant results are compared in the table below:

Output Parameter GiD+OpenSees SeismoStruct 2016
Period T1 [sec] (1st mode) 0.2495 0.2271
Period T2 [sec] (2nd mode) 0.2337 0.2156
Period T3 [sec] (3rd mode) 0.0759 0.0733
Period T4 [sec] (4th mode) 0.0741 0.0720

Fani Derveni, Vassilis K. Papanikolaou

Developed in the Lab of R/C and Masonry Structures, School of Civil Engineering, Aristotle University of Thessaloniki, Greece, by T. Kartalis-Kaounis, V.K. Protopapadakis and T. Papadopoulos, Dipl. Civil Engineers, under the coordination of V.K. Papanikolaou, Assistant Professor.

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