How does SSI Schaefer racking withstand an earthquake?

Friday, June 1st, 2012

The answer is simple. SSI Schaefer racking is designed to consider the regional environment where the equipment will be installed and is a system of racking instead of components.

The following is an example taken for an earthquake that affected Christchurch in New Zealand.
New Zealand is classified under either Zone 2 or 4 based on the historical number of past earthquakes. SSI Schaefer strictly adhere to, and base all racking design for New Zealand around FEM 10.02.02 and NZS 1170.5 – 2004 (seismic code) and or Uniform Building Code 1997 edition – Vol.2 Division IV ‘Earthquake Design’.

Based on the New Zealand codes SSI Schaefer takes into consideration:

  • The pallet load and seismic action are applied on cross aisle and down aisle direction.
  • The action forces are based on the New Zealand standards.
  • The frame profile and bracing requirements are determined by forces acting on cross aisle direction.
  • The beam profile and spine/plan bracing is determined by forces acting on down aisle direction and rack configuration used.
  • Ductility.
  • The rigidity and strength of the racking system is determined by the profiles properties, material properties, the connection strength and stiffness.

The materials they are using to manufacture all components are controlled and higher than the international standards. For example the post is made from SS490 (as JIS) with minimum yield strength of 390N/mm^2.

The requirement of JIS is 285N/mm^2. All SSI Schaefer materials are purchased directly from Steel mills and will verify the requirement base on a Mill certificate and independent tensile test report.

The racking is checked in the static calculation as below:

  1. Base plate size and thickness as per requirement (vertical force and shear force).
  2. Floor fixing as per requirement (vertical force and shear force).
  3. Post profile selection based on compression force and bending.
  4. Frame bracing check based on tension capacity and bearing.
  5. Beam design.
  6. Spine and plan bracing component checking.
  7. Point load acting on floor by racking post and spine bracing.
  8. In addition, SSI Schaefer column tests are extremely rigid and follow stricter guidelines than other racking.

The column test sample is equipped with a load cell and linked to a measurement device to monitor the behavior of the column in the load test.

The accurate and precise measurement of the test ensures that the team has a greater understanding of the exact behaviour of the post and guarantees a quality system for the customer.

Is your warehouse or building in an earthquake zone?

If your warehouse has received damage from the earthquakes and you have not had your racking tested then do so immediately.

You may have structural damage to the racking foundations and not even realise it.

One more aftershock could potentially cause problems for your racking and may risk the safety of your workers.
Stop and assess your current racking; does it adhere to the local Building Codes? Can it withstand earthquakes?
Aftershocks can occur for up to twelve months after an earthquake, why risk the safety of your workers when a simple test can be carried out on your existing racking which can assess any structural damage that may have occurred.

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