Efficiency of Post-Tensioning Method for Seismic Retrofitting of Pre-Cast Cylindrical Concrete Reservoirs

Cylindrical concrete reservoirs are appropriate choice for storing liquids as water, oil and etc. By using of the pre-cast concrete reservoirs instead of the in-situ constructed reservoirs, the speed and precision of the construction would considerably increase. In this construction method, wall and roof panels would make in factory with high quality materials and precise controlling. Then, pre-cast wall and roof panels would carry out to the construction site for assembling. This method has a few faults such as: the existing weeks in connection of wall panels together and wall panels to foundation. Therefore, these have to be resisted under applied loads such as seismic load. One of the innovative methods which was successfully applied for seismic retrofitting of numerous pre-cast cylindrical water reservoirs in New Zealand, using of the high tensile cables around the reservoirs and post-tensioning them. In this paper, analytical modeling of wall and roof panels and post-tensioned cables are carried out with finite element method and the effect of height to diameter ratio, post-tensioning force value, liquid level in reservoir, installing position of tendons on seismic response of reservoirs are investigated.

Authors:

• M.E.Karbaschi
• R.Goudarzizadeh
• N.Hedayat

Keywords:

• Seismic Retrofit
• Pre-Cast
• Concrete Reservoir
• Post-Tensioning.

References:

[1] http://www. shaymurtagh.ie
[2] http://www.stresscrete.ie
[3] ACI Committee 350 2001, Seismic design of liquid-containing concrete
structures (ACI 350.3-01) and commentary (350.3R-01), American
Concrete Institute, Farmington Hills, Mich.
[4] Design and calculations of on ground reservoirs, building code 123,2th
edition (1995), management organization of country (IRAN).
[5] Salajegheh, J., Design of on ground water reservoirs, Kerman
University Publications, 2007.
[6] Nourali ahari, M., Eshghi, S.," Seismic vulnerability of steel oil
reservoirs", Proc 4th Int. Conference Earthquake Engineering, 2003,
Iran, Tehran.
[7] Nourali ahari, M., Eshghi, S.," Siesmic response of unbraced cylindrical
steel reservoir in horizontal earthquake motions", 2th Thin Wall
Structures Conference, 2005, Tehran.
[8] Khaloo, A. R., Design of pre-stressed concrete structures, Sineh Sorkh
publications, Tehran, 2003.
[9] Taylor, R.G., Wright, P.D., "Innovative seismic retrofit of concrete
water supply tanks", 2003 pacific conference on earthquake engineering.
[10] Dehdashti, G. (1994). "Shape formation and ultimate load behavior of
post-tensioned space trusses." PhD Thesis, Univ. of Wollongong,
Australia.
[11] Iranian code of practice for seismic resistant design of buildings,
Standard no. 2800-84, Building and Housing Research Center.
[12] SAP 2000, Ver.11, Manual.