Reduction of Major Seismic Forces with Bearings and Isolation Techniques: Alexisismon


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Title: Reduction of Major Seismic Forces with Bearings and Isolation Techniques: Alexisismon

Author(s): A. S. lkonomou

Publication: Special Publication

Volume: 70


Appears on pages(s): 525-547

Keywords: bearing capacity; bearings; bridge bearings; costs; earthquake resistant structures; foundations; isolation joints; joints (junctions); loads (forces); structural analysis; structural design.

Date: 1/1/1981

This paper presents a study for the application to the Snake River Bridge, State of Washington, U.S., of the Alexisismon, a base isolation system developed over the last 13 years by the author, which allows the structure not to be affected by a strong earthquake beyond a low level, owing to a reduction of the horizontal seismic forces transferred to the structure by a factor of 10 to 20. This system is composed of the Alexisismon Supports, which transfer the vertical loads of the superstructure to the foundation and, in case of earthquake, all the horizontal forces, the Alexisismon Connections, which firmly connect the superstructure with the foundation as long as no earthquake occurs and the Alexisismon Disc, which provides the horizontal joint for the vertical elements of the superstructure. In the case of this bridge, the A.S. are elastic rubber and sliding pot bearings, the A.C. are twelve vertical bars of reduced breakable middle cross-section and the A.D. is the superstructure of the bridge. Even in this unfavorable case of a flexible structure, the results of the statical analysis show, for 1.5 9, friction, a great reduction by 10.5 of the maximum hori- zontal seismic forces transferred to the ground for the case of the Pacoima Dam SI6E earthquake (peak acceleration: 1.24 g) .