Keywords: acceleration, deformation, earthquake, motion, frustum, hinge.

The inertial force, which reveals itself in a building due to the undulatory shock of an earthquake, is generally shown in diagram form by systems of concentrated horizontal forces applied to the floors. The method proposed in this study is based on the hypothesis that the distribution of the inertial force is linear along the height of the building, in accordance with the fact that the weight of a building with constant transverse section varies linearly from the top to bottom.

It is also presumed that the building consists of a succession of hinged partial frustums with constant height, which are connected to one another by means of fixed hinges located at both the top and bottom each frustum in order to allow a frustum to rotate with respect to its adjacent frustums in the vertical plain only. Each intermediate frustum - from the lowest to the second highest - is transversely stiffened, at both the base and the summit, by appropriately dimensioned slabs, therefore behaving with respect to the bending and shear stresses like a beam perfectly fixed to the ends with elastic angular deformations.

The considerable rigidity of the slabs with respect to the rigidity of the pillars present in the frustum allows this fixing state to be adopted as the most suitable. On the other hand, the top frustum behaves like a cantilever truss perfectly fixed to one end and with elastic angular deformation at the opposite end. In order to confer the building with the same rigidity with respect to the any direction of the earthquake and to decrease the torsional effects, its ideal geometrical plan is obviously circular - and then regular polygonal and square - with circular section pillars and reinforced steel symmetrically placed with respect to any axis of the section.

However, there is nothing to prevent the construction of buildings that - due to elaborate architectonic requirements - must have different geometrical plans, provided, with the use of appropriate joints, they can be disassembled into bodies of a very simple plan, at least square. With regard to the first frustum at the top, the bending and shear stresses concerning the dynamic configuration with vertical hinges (2nd Configuration) are equal to the corresponding stresses of the configuration without vertical hinges (1st Configuration).

However, with reference to the other frustums, proceeding from top to bottom, the bending and shear stresses concerning the 2nd configuration are maximum in correspondence of the second frustum and they decrease rapidly from the following frustum until becoming negligible. Their percentage values are much lower than the corresponding values of the 1st configuration. This is the reason behind the considerable economic advantage of the configuration with hinges with respect to the configuration without hinges.

1

Bartolozzi, F., "System of Base Seismic Isolation with the Project of the Stiff Connection with Alternative Function of Elastic Anti-seismic Linkage", in "Proceedings of the Second International Conference on Seismology and Earthquake Engineering", Tehran, Iran, 15-17 May, 2013-2021, 1995.

2

Bartolozzi, F., "System of Base Seismic Isolation with the Project of the Fixed Bearing with Alternative Function of Multidirectional Movable Bearing", in "Proceedings of the International Conference on Earthquakes, Volcanoes and Tsunamis, Pan Pacific Hazards'96", Vancouver, Canada, 29 July-2 August, Paper in CD-rom and Abstract in Book, 23, 1996.

3

Bartolozzi, F., "Self-centring Aseismic System with Four Rigid Movable Bearings", in "Proceedings of the Fourth National Conference on Earthquake Engineering", Ankara, Turkey, 17-19 September, 536-541, 1997.

4

Bartolozzi, F., "Self-centring Aseismic Aystem with Four Elastic Bearings and Frequency Converters", in "Proceedings of the Eleventh European Conference on Earthquake Engineering", Paris, France, 6-11 September, Paper in CD-rom and Abstract in Book, 365, 1998.

5

Bartolozzi, F., "Centring and Locking Aseismic Bearing", in "Proceedings of the 2nd International Conference on Control of Oscillations and Chaos", St. Petersburg, Russia, 6-9 June, Volume 1, 124-125, 2000. doi:10.1109/COC.2000.873529

6

Bartolozzi, F., "Self-centring Aseismic System with Double Natural Frequency", in "Proceedings of the Fifth International Conference on Motion and Vibration Control 2000", Sydney, Australia, 4-8 December, 163-166, 2000.

7

Bartolozzi, F., "Aseismic Bearing with Partially or Totally Curved Sliding Surface and with Angular Corrector", in "Proceedings of TIEMS2001, International Conference on Emergency Management", Oslo, Norway, 19-22 June, Paper in CD-rom, 2001.

8

Bartolozzi, F., "Natural Frequency Automatic Variation in Seismic Isolation System", in "Proceedings of ACOMEN 2002, 2nd International Conference on Advanced Computational Methods in Engineering", Liège, Belgium, 28-31 May, Paper in CD-rom, 2002.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £135 +P&P)