Non-linear seismic response of circular presetressed reservoirs

Student: Christos Baltos
Supervisor: Prof. M.J.N. Priestley, Dr R. Pinho

Abstract

The scope of this project is to investigate the non-linear seismic response of circular prestressed concrete reservoirs tanks of different configurations designed under current design codes [1,2,8,9] using a beam on elastic foundation model [10,14,15] and determine effective force reduction factors for seismic design cases and safe PGA for the non seismic design case.

Modeling assumptions are presented for the analysis of cylindrical concrete storage tanks as those are covered by standard texts on the design of circular reservoirs. A comprehensive review and application of the Force-Based Design approach of circular prestressed reservoirs structures when subjected to seismic action in the transverse direction is presented. The design procedure to use with this type of structure is presented first, followed by a series of applications to different possible tank configurations.

Assessment of the tanks designed is carried out using pushover and time-history analyses. Models including inelasticity for pushover and time-history analyses are presented. The pushover analysis indicates the multiple of code seismic load that each tank can sustain revealing the effectiveness of code reduction factors used for their design. Incremental dynamic analysis is carried out by using multiple of time-histories that codes impose indicating the conservatism of the seismic design of the circular prestressed concrete reservoir.

Finally some design and analysis aspects of sliding base tanks are presented.

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