چکیده:
There are some important buildings which their performance level (PL) should not
be lower than immediate occupancy (IO) based on the recent seismic design codes.
The most common way for achieving this PL is using seismic isolation technique.
However this technique has not been acknowledged worldwide so much,
particularly in developing countries, mainly due to the high cost and the relatively
large required free space around the building which is not usually acceptable for
the buildings’ owners. Another approach for achieving IO PL, proposed in recent
years, is using a structural system which can have seesaw motion during an
earthquake, and at the same time dissipate a major part of the input energy in its
specific dampers or structural fuses, which can be easily replaced after the
earthquake. The building with such a system which can be called ‘seesaw building’
needs to have, in addition to the structural fuses, a specific central support and a
grid of strong girders at its lowest floor. These additional components add some
cost to the costs of the building’s structural system. The aim of this study is
comparing the efficiency of common seismic isolation technique with that of the
seesaw building, from both seismic performance and construction costs aspects.
Special attention has been paid to the near-field earthquake to which the common
isolation systems are weak. For comparing the seismic behaviors of the two
systems, responses of the considered counterpart buildings have been obtained by
a series of nonlinear time history analysis by using a set of selected far- and nearfield
earthquakes. Numerical results show that the seesaw building generally
behaves better than isolated buildings, with less lateral displacements, and its cost
is relatively lower as well. The only shortcoming of the seesaw building is its very
little residual displacement at the end of the earthquake, which necessitates some
attempts for bringing it back to the original position.
خلاصه ماشینی:
Comparing the Efficiency of Seismic Isolation and Seesaw Motion in Multi-story Regular Steel Buildings for Achieving the Immediate Occupancy Performance Level Soroush Kherad*1, Mahmood Hosseini2 1- Doctorate Student, Islamic Azad Univ.
Recently, the first author of this paper has used the idea of rocking motion of building in combination with a central fuse, which works as a huge plastic hinge under the vertical load and the moment, induced by the lateral seismic load (Hosseini and Kherad 2013).
In this study the DDD idea has been employed for design of regular steel multi-storey buildings, which have rocking motion, by using inclined columns around the central main vertical column of the building at its base level.
The inclined columns, which their bases have been shifted toward the centre of the building plan and cause the building to move basically in rocking motion during an earthquake, are equipped with Double-ADAS (DADAS) devices (Hosseini and Bozorgzadeh 2013), which play the main role of energy dissipating devices or fuses.
Considering the advantages of the proposed rocking and energy-dissipating structural system in seismic reduction of mid-rise multi-story buildings, and particularly the easiness of manufacturing and installation of the CED devices, the use of this system can be strongly recommended for buildings in the vicinity of active faults, particularly in large populated cities.
[8] M Hosseini and S Kherad, “A Multi-Stud Energy Dissipating Device as the Central Fuse to Be Used in Short- to Mid-Rise Regular Steel Buildings with Rocking Motion,” Proceedings of the International Van Earthquake Symposium, Van, Turkey, October 2013