AK4S
Structural
- Jan 2, 2015
- 98
I am working on the seismic analysis and design of partially buried / ground-supported liquid storage tanks and I am looking for some guidance regarding the analysis and design approach.
• ASCE 7-05,Section 15.7.6 covers ground-supported storage tanks and provides equations for calculation of base shear (also considering hydrodynamic forces)
• ACI 350.3-06 provides details of calculation of inertia forces from the tank structure and hydrodynamic forces due to the fluid content.
From what I could gather:
• Use ASCE 7-05,Section 15.7.6 to calculate seismic base shear forces. This would be the total horizontal force acting on the tank foundation structure (piles in my case).
• Use ACI 350.3-06 for calculation of seismic loads on each wall (based on its location and orientation, I would need to consider a sum of squares combination of the applicable inertia forces, hydrodynamic and dynamic earth pressure forces). Use this seismic load along with other loads (Dead and Live loads, Hydrostatic pressure) and design the wall for critical conditions using the applicable load combinations (ACI 350-sppendix C in my case).
I would appreciate if someone with prior experience in this field can guide me with my approach or point me in the right direction.
• ASCE 7-05,Section 15.7.6 covers ground-supported storage tanks and provides equations for calculation of base shear (also considering hydrodynamic forces)
• ACI 350.3-06 provides details of calculation of inertia forces from the tank structure and hydrodynamic forces due to the fluid content.
From what I could gather:
• Use ASCE 7-05,Section 15.7.6 to calculate seismic base shear forces. This would be the total horizontal force acting on the tank foundation structure (piles in my case).
Query:
o Can I use this provision to calculate the seismic base shear of the tank. i.e. the seismic shear force transferred to the foundation system
o How do I calculate the fundamental period of the tank structure and impulsive component of the content, Ti? What is the stiffness and mass to be considered? Can anybody provide me a reference on how to calculate them? How can I account for the internal walls in the tank for the stiffness calculation?
o How do I calculate the impulsive and convective weight components of the fluid? Can I use the mass factor charts in chapter 9 of ACI 350.3-06 to determine these values?• Use ACI 350.3-06 for calculation of seismic loads on each wall (based on its location and orientation, I would need to consider a sum of squares combination of the applicable inertia forces, hydrodynamic and dynamic earth pressure forces). Use this seismic load along with other loads (Dead and Live loads, Hydrostatic pressure) and design the wall for critical conditions using the applicable load combinations (ACI 350-sppendix C in my case).
Query:Can I use the above approach (using ACI 350.3-06) to obtain the seismic load on the walls.I would appreciate if someone with prior experience in this field can guide me with my approach or point me in the right direction.
