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Earthquake

Japan, the home country of Daifuku Co., Ltd., is the world famous earthquake country where earthquakes are daily occurrence. Daifuku has grown up its material handling business in such environment since 1937 and has accumulated expertise through several huge earthquakes marked in the history.


Why seismic tremor control is needed

Unlike the general image of earthquake, "collapse", we did not observe much damage to racks and rack-supported buildings that are designed in line with the safety and construction regulations. The major issues we observed are;

  1. 1. Damage of stored loads due to fall-off from pallets
  2. 2. Damage of material handling equipment due to fallen loads or pallets
  3. 3. Difficulty of recovery work on collapsed loads at high place
  4. 4. Loss from business interruption

To minimize such business risk, Daifuku sees it important to;

  1. 1. Minimize rack sway
  2. 2. Avoid load collapse from pallet
  3. 3. Avoid pallet fall off from rack

Where seismic tremor control is needed

According to USGS, other countries known as earthquake countries are China, Indonesia, Iran, Turkey, Peru, USA (Alaska, California), Italy, Chile and so on. When planning AS/RS in these countries, it is essential to think how to minimize the above mentioned risk.


Daifuku's seismic tremor control solutions

Daifuku offers varieties of seismic control solutions that can be applied alone or combined according to needs.

Applied to Solutions Power of tremor
25~80 gal 80~140 gal 140~250 gal 250~400 gal
Load Wrapping, binding
Rack Fixed stoppers
Quake-absorbing stoppers
Quake-absorbing rack +
Quake-absorbing stopper
Seismically isolated rack
Control Seismograph
Location control by stability

1. Stretch-wrapping / Binding / Box pallet application

One of the effective ways to reduce the load turnover risk is to stabilize loads by stretch-wrapping, binding or roll box pallet application. However, it is not always possible to do so due to operational reason such as case picking requirement.

stretch wrapped pallet
Stretch-wrapped pallet
bind, tie
Loads bound at the top
roll box pallet
Roll box pallet

2. Fixed Stoppers at rack locations

Fixed stoppers installed in rack locations prevent pallet movement into crane aisle during earthquakes. They work effectively when combined with stretch-wrapping and binding. However, they cannot prevent loads on pallets from protruding or falling when stretch-wrapping or biding is not applicable.

fixed stopper for earthquake
fixed stopper for earthqua

3. Quake-absorbing Stoppers at rack locations

Quake-absorbing stoppers installed in rack locations absorb the collision energy and reduce load fall-off risk.
They can be applied to both newly built and existing racks.

quake-absorbing stopper for earthquake

4. Quake-absorbing Rack

Dampers installed at the top of AS/RS racks reduce energy of seismic activity by up to 50%, reducing the potential for loads to fall of the racks during earthquakes. Dampers can be installed on both existing and newly built racks.

quake absorbing rack for earthquake
quake absorbing rack for earthquake
The damper at the top of rack converts the seismic energy to heat by repeating pulling and compressing.

5. Seismically Isolated Rack

A seismically isolated AS/RS base severs AS/RS from direct influence of earthquake tremors.

seismically isolated rack
Seismically isolated rack
bearing isolator of seismically isolated rack
1. Bearing isolator
hydraulic damper of seismically isolated rack
2. Hydraulic damper

6. Seismograph / Seismometer

When the seismograph detects a significant tremor, the equipment controller sends cycle stop signals to all equipment to reduce the potential for damage.

seismometer connected to equipment controller

7. Location control by stability

Ordinary random storage management places pallets in any available location. This means that tall, unstable loads may be stored on higher levels where the impact of earthquakes is greater. With load stability information registered, WMS can limit location assignment for unstable loads to only lower levels, reducing the risk of loads falling during earthquakes.

ordinary random storage
Ordinary random storage
location management by load stability
Management by stability

Case Study

Nissin Pharmaceutical

Seismically isolated AS/RS strengthens steady supply of generic drugs.

Contact Daifuku