SEISMIC SOIL–FOUNDATION–STRUCTURE INTERACTION ANALYSIS OF DEEPLY EMBEDDED VENTILATION STACK

2012 ◽  
Vol 06 (01) ◽  
pp. 1250003
Author(s):  
V. JAYA ◽  
G. R. DODAGOUDAR ◽  
A. BOOMINATHAN
Keyword(s):  
Seismic Response ◽  
Interaction Analysis ◽  
Strong Dependence ◽  
Velocity Ratio ◽  
Relative Displacement ◽  
Response Analysis ◽  
Structure Interaction ◽  
Soil Foundation ◽  
A Site ◽  
Foundation Structure

In this paper, the seismic response analysis of deeply embedded ventilation stack is addressed by considering the effects of soil–foundation–structure interaction (SFSI). Seismic SFSI analysis of the stack subjected to a site-specific design ground motion is carried out using finite element method. A parametric sensitivity analysis is made to investigate the effect of embedment and shear wave velocity ratio of the subsurface profile on the seismic response of the stack. The first series of the SFSI analysis is carried out for the stack with surface footing using computer program SASSI 2000. The second set of analysis incorporates the effect of embedment on the seismic response of the stack. The flexible volume substructure method is used to analyze the seismic SFSI effects. It has been found that the seismic response at the various levels of the stack shows a strong dependence on stiffness of the subsurface profile and the depth of embedment. The spectral acceleration and relative displacement at the top of the stack decrease with increase in embedment ratio and these are the important parameters to be given a due consideration during design process of the stack structures.

Comparison between standards for seismic design of liquid storage tanks with respect to soil-foundation-structure interaction and uplift

2012 ◽  
Vol 45 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Miguel Ormeño ◽  
Tam Larkin ◽  
Nawawi Chouw
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Earthquake Engineering ◽  
Storage Tanks ◽  
Base Shear ◽  
Structure Interaction ◽  
Liquid Storage ◽  
Field Evidence ◽  
Soil Foundation ◽  
Foundation Structure

Field evidence has established that strong earthquakes can cause severe damage or even collapse of liquid storage tanks. Many tanks worldwide are built near the coast on soft soils of marginal quality. Because of the difference in stiffness between the tank (rigid), foundation (rigid) and the soil (flexible), soil-foundation-structure interaction (SFSI) has an important effect on the seismic response, often causing an elongation of the period of the impulsive mode. This elongation is likely to produce a significant change in the seismic response of the tank and will affect the loading on the structure. An issue not well understood, in the case of unanchored tanks, is uplift of the tank base that usually occurs under anything more than moderate dynamic loading. This paper presents a comparison of the loads obtained using “Appendix E of API STANDARD 650” of the American Petroleum Institute and the “Seismic Design of Storage Tanks” produced by the New Zealand Society for Earthquake Engineering. The seismic response assessed using both codes is presented for a range of tanks incorporating a range of the most relevant parameters in design. The results obtained from the analyses showed that both standards provide similar base shear and overturning moment; however, the results given for the anchorage requirement and uplift are different.

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