×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

SAP2000 - RC Rectangular Water Tank

SAP2000 - RC Rectangular Water Tank

SAP2000 - RC Rectangular Water Tank

(OP)
Hi all, I am working on the design of a RC water tank, and I need your help...!!
Thanks in advance!!!!

Size and Structural Form

RC Rectangular Water Tank
- Designed as a Rigid Box Structure, as the Roof, Base & Walls are all monolithically connected
- Size of the Tank = 68m (Length) x 30m (Width) x 9m (Height)
- Thickness of Roof, Base, Walls = 0.4m



Baffle Walls
- 3 Baffle Walls inside the tank to guide the flow of water
- Designed to be Full-height Structural Wall transfering load from the Roof to the Base
- Not Full-length in order to allow water flow



Foundation
- Shallow Foundation sitting directly on Soil
- Base Slab acts as Foundation

Questions

1. How to model the Slab Foundation?
- In RC building, fixed-end supports are added to the column ends.
- For Slab Foundation, should I use Area Spring (z-axis)& Soil Spring (x & y-axis) at Base Slab?
- Do I need to restrain (i.e. to fix) the lateral (x & y) movement?


2. What is the structural behaviour of the tank under seismic loading?
- The analysis shows that the roof has large in-plane deformation, resulting in high tension at far side, and compression at near side.
- The behaviour is similar to a beam sagging under UDL (compression at top; tension at bottom).
- The Roof does not act as a rigid diaphragm, but a flexible one.
- I reckon it is the actual behaviour, as the roof and the walls have same thickness, yet the roof has a much longer span (68m) while the wall is just 9m tall. The in-plane stiffness of the Roof should be smaller than the Walls. Given the smaller relative stiffness, the roof is flexible.
- To be clear, I used Area Spring (z) and Soil Spring (x & y) at Base Slab, not sure if it affects the result???

3. Seismic Loading of the Tank
- Could anyone advise what is the best way to model the seismic loading?
- I tried equivalent lateral load method and response spectrum modal analysis method.
- The eq. lateral load method greatly amplify the effect in Q2 (Compression at Near Side of Roof, Tension at Far Side of Roof)

4. Interpretation of Shell Element Result
- Is F11 and F22 representing the Axial Load?
- Since I have large F11 & F22 in the Shell Element on Wall, does it mean that I have to design it as a column in both 11 & 22 axis?

RE: SAP2000 - RC Rectangular Water Tank

I think you should start from a simpler structure!

Jason McKee
proud R&D Manager of
Cross Section Analysis & Design
Software for the structural design of cross sections
Moment Curvature Analysis
Reifnorcement Design etc.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources