Seismic Calculations–What Are They and When Are They Needed–Quick Tanks Tech Topic 1, April 2016

Quick Tanks Inc. Tech Topic #1 – April 2016

Download this file in .pdf format, here.Download this 'Seismic Calculations: What are they? When are they needed?' in Adobe .pdf format through this link

Seismic calculations are used to calculate leg & saddle support strength for vessels during earthquakes.

 

Seismic Calculations are needed when:
  1. Specification requires seismic calculations
  2. Federal or State requirement
  3. Project is going into a hospital, federal facility or heavy industrial facility.

Quick Tanks can provide these calculations, including those required in California.

Pressure Vessel / Water Tank manufactured by Quick Tanks With Seismic Calculations Included In The Design Process

1989 World Series Game 3 Stopped for an Earthquake. Seismic calculations are used to calculate leg & saddle support strength for vessels during earthquakes.

1989 World Series Game 3 Stopped for an Earthquake
1989 Loma Prieta Earthquake First 30 Seconds. Seismic Calculations Matter When Designing and Manufacturing Your Projects.1989 Loma Prieta Earthquake First 30 Seconds

If seismic calcs are needed, fill out our Seismic Data Request Form‘ that you can download here.

The form asks for your site data, type of facility and strength/thickness of concrete.  It goes hand in hand with our Quick RFQ found here.

NOTE: SEISMIC CALCULATIONS SHOULD NOT BE REQUESTED AFTER THE FACT. Seismic calcs often increase the size of supports to accommodate earthquake forces. Rejection of a system already on site due to supports being inadequate will ruin your day.

The old “Zones 1, 2, 3 or 4” are no longer used. 

Your site’s physical address or zip code is entered into a USGS1 database to determine the site-specific seismic data.  The USGS site-specific seismic data, when mapped, looks like a topographic map of elevations with continuous lines separating the acceleration values.  The analytical method from ASCE-72 is used as directed by IBC3-yr. Data is available for the US & Canada, data from other nations is imprecise–You must require your customer to provide foreign country data that can be used in IBC.

Two fundamental areas are evaluated by seismic calcs:

  1. Strength of legs (vertical tank) or saddles (horizontal tank)
  2. Holding power: bolts embedded in concrete.

Additional evaluations include: stress on footpad (or baseplate), size of the footpad (do not want to over-stress concrete in compression) and shell stresses from supports. If vessel(s) will be mounted to a frame (aka “skid”), seismic calcs include the frame.

CALIFORNIA RULES FOR HOSPITALS & HEALTH CARE FACILITIES:

OSHPD4 rules require special calcs and must be done by a California PE (SE)5.

1USGS – US Geodetic Survey
2ASCE-7 – American Society of Civil Engineering, Minimum Design Loads for Buildings and Other Structures
3IBC – International Building Code
4OSHPD – Office of Statewide Health Planning and Development
5PE (SE) – California Professional Engineer, registered as a Structural Engineer

Download this file in .pdf format, here.Download this 'Seismic Calculations: What are they? When are they needed?' in Adobe .pdf format through this link

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