Seismic Load Design for Liquid Containing Tank using ASCE 7-16 in accordance to seismic hazard assessment for Design of Earthquake of the Philippines

Technical Overview

This comprehensive Excel workbook provides a complete seismic load design for liquid-containing rectangular concrete tanks. The technical approach strictly follows the dynamic analysis procedures outlined in ASCE 7-16 Chapter 11 and ACI 350.3-2020, and is specifically adapted for seismic hazard assessments in the Philippines (DOST SHADE).

Key Features

• Dynamic Liquid Modeling: Accurately partitions the contained liquid into Impulsive (rigid) and Convective (sloshing) masses to calculate realistic hydrodynamic forces.
• Automated ASCE 7-16 Parameters: Readily calculates Site Coefficients ($F_a$, $Fv$) and Design Spectral Response Accelerations ($S{DS}$, $S_{D1}$).
• Overturning & Pressure Diagrams: Computes the distribution of lateral inertial pressures from both impulsive and convective modes over the height of the tank walls.
• Code Referencing: Extensive, line-by-line citations to ACI 350.3 and ASCE 7-16 tables and figures for easy independent verification.
• Supplementary RC Design: Includes integrated modules for LRFD load combinations and reinforced concrete capacity checks (shear and flexure).

How to Use

1. Input Geometry: Enter tank dimensions, wall thicknesses, and liquid height on the Summary tab.
2. Define Materials: Specify concrete compressive strength and soil/liquid unit weights.
3. Set Seismic Hazard: Enter the mapped spectral accelerations and site class based on your specific location (e.g., via DOST SHADE).
4. Review Hydrodynamic Loads: The workbook automatically yields the total base shear and the lateral pressure profile required for structural analysis of the walls.

Overall verdict: ✅ Approved for Publication. A highly technical and perfectly executed engineering tool.

Mathematical Model & Technical Approach

The workbook adopts a rigorous, multi-step technical approach to evaluate the hydrodynamic forces on the tank structure:

1. Seismic Parameters (ASCE 7-16 Chapter 11):
   • Calculates design spectral response accelerations ($S{DS}$, $S{D1}$) based on user-defined site classifications (e.g., Site Class D) and mapped MCE parameters ($S_s$, $S_1$).
2. Dynamic Mass Partitioning (ACI 350.3-2020):
   • Correctly partitions the total liquid mass into Impulsive ($W_i$) and Convective ($W_c$) components. The impulsive mass moves rigidly with the tank wall, while the convective mass represents the sloshing liquid near the surface.
3. Period of Oscillation:
   • Determines the fundamental period of the tank/impulsive mass system ($T_i$) and the fundamental period of the sloshing liquid ($T_c$).
4. Seismic Response Coefficients:
   • Calculates independent seismic base shear coefficients for both the impulsive ($C_i$) and convective ($C_c$) modes.
5. Hydrodynamic Pressure Distribution:
   • Determines the lateral inertial pressures on walls and roof.
   • Computes the vertical distribution of the total lateral impulsive pressure ($P{iy}$) and total lateral convective pressure ($P{cy}$) to accurately determine overturning moments and wall bending stresses.
6. Reinforced Concrete Design:
   • Includes supplementary modules (like "Stair Case Beam Design") that perform LRFD load combinations, shear capacity checks, and flexural reinforcement design based on the derived loads.

Application

While generalized for ASCE 7-16, the tool is thoughtfully pre-configured to assist engineers working with the Philippine DOST SHADE (Seismic Hazard Assessment for Design of Earthquake) data, making it highly valuable for civil/structural engineers in that region.

Quality Checklist Review

• [Y] Verify submitter ownership (Aaron Casey Lorecto)
• [Y] Check for duplication in repository (Unique and specialized submission)
• [Y] Confirm file is unprotected (Full formula access allowed)
• [Y] Review submission category appropriateness (Strength / Seismic)
• [Y] Clear sketches/diagrams included (Visual aids provided on the download/preview page)
• [Y] Logical presentation flow (Excellent breakdown from Geometry → Seismic Parameters → Pressures)
• [Y] References to standards (Explicit line-by-line references to ACI 350.3-2020 Figures/Sections and ASCE 7-16)

Note: This calculation does not utilize the XLC Add-in for equation rendering, relying instead on standard Excel formulas. However, the step-by-step tabulation and clear code referencing mitigate this and maintain an acceptable level of auditability.