Abstract: (12055 Views)
Abstract:
Appealing to the principle of vertical residence and stemming the horizontal expansion of the
city, the Tehran Milad Tower is being built on 35000 sm3 site with the total area of 220000
sm3. With a height of over 170m, this 56-story concrete building is in the final stages of
construction and would be the highest residential building of Iran. Since Tehran is located in a
high-risk earthquake zone, all of its structures must be designed for seismic loads. In this
building, the lateral loads are carried with three main shear walls, which are located in an
angle of 120 degrees and the gravity loads are transferred from the concrete slabs to the
secondary shear walls.
Since the introduction of Tuned Mass Dampers (TMD) by Frahm in 1909, as a passive control
system, numerous investigations have been carried out to examine the effect of these devices
in reducing seismic response of the structures. The objective of incorporating a TMD into a
structures is to reduce the energy dissipation demand on the primary structural members
subjected to external forces. This reduction is accomplished by transferring some of the
structural vibration energy to the TMD and dissipating the energy at the damper of TMD.
The purpose of this paper is to design and evaluate the effectiveness of TMD for response
reduction of the Tehran tower under seismic excitations. A lumped mass model of the
building was provided with 112 translational and 56 rotational degrees of freedom using solid
and shell elements. Time history analyses were performed to calculate the response of the
structure subjected to some earthquake records. The same procedure was followed for the
models with attached TMD. The control effectiveness of TMD was evaluated by comparing
the tower's responses with those of the towers without control device. Furthermore, multiple
tuned mass dampers are suggested as a solution for insufficiency of TMD.
Received: 2008/12/27 | Accepted: 2010/09/29 | Published: 2011/03/2