Seismic Design of Storage Racks — DPT 1311, ASCE 7-22, FEM 10.2.08 for Warehouses in Thailand

A 6-metre pallet rack loaded to capacity is a large mass raised high above the floor. When seismic shaking occurs, a rack not designed for lateral forces can collapse an entire row in a domino failure — destroying stock, injuring workers, and halting the warehouse.

Many assume "Thailand rarely has earthquakes, so don't worry" — a dangerous misconception, especially in Bangkok and its surroundings. This article explains why, and which standards to design to.

1. Why Bangkok Must Consider Seismic — Soil Amplification

Bangkok has no active fault beneath the city, but it sits on tens of metres of soft clay that acts like jelly, amplifying seismic waves from distant sources:

• The Sagaing Fault in Myanmar — 400+ km away, but long-period waves travel that far and are amplified by Bangkok's soil
• Faults in Kanchanaburi / northern / western Thailand — closer

The result: ground-surface acceleration in Bangkok can be several times higher than on bedrock for long-period waves — and tall racks, whose natural period is long, can resonate with exactly these waves.

DPT Standard 1311-50 (Department of Public Works and Town & Country Planning) designates Bangkok as a region requiring seismic forces in structural design — covering heavy storage racks.

2. Standards Used for Seismic Racking

The Thailand approach: use regional forces from DPT 1311 as input to FEM 10.2.08 / EN 16681 or ANSI MH16.1 + ASCE 7-22, then have a licensed Thai civil engineer certify it — government TORs usually require this.

3. How Seismic Racking Differs from Ordinary Racking

flowchart TD
  A[Stored mass on rack] --> B[Compute base shear
V = Cs x W]
  B --> C{Lateral force
down-aisle + cross-aisle}
  C --> D[Columns/beams + bracing
resist cyclic moment]
  C --> E[Base plate + anchor
resist pull-out]
  C --> F[Row spacer / overhead tie
tie rows together]
  D --> G[Check drift + P-delta]
  E --> G
  F --> G
  G --> H[Engineer certifies + load sign]

Elements added versus ordinary racking:

1. Base shear (V = Cs × W) — base shear from stored mass × seismic coefficient (Cs from regional values + soil type + system R)
2. Base plate + anchor designed for pull-out — anchor bolts must resist pull-out from overturning moment (the most common failure point)
3. Bracing / beam-to-column connections for reversing (cyclic) loads
4. Row spacers / cross-aisle ties to distribute force and reduce single-frame collapse
5. Drift and P-delta checks — lateral sway must stay within limits

4. What Government TORs Usually Require

• Cited standards (DPT 1311 + FEM/EN or ANSI MH16.1/ASCE 7)
• Drawings and calculations certified by a civil engineer (license + signature)
• Base shear, anchor, and base-plate calculation sheets
• Load capacity signs on every row (kg/bay, kg/level)
• Steel material certificates (TIS/mill cert) + anti-corrosion coating

5. Checklist Before Ordering Racks for Seismic Work

1. State the install location (Bangkok metro vs upcountry) at quote stage — regional forces differ
2. Provide real pallet weights + heights — they set the base shear
3. Ask for certified drawings + calculations, not just a catalog
4. Verify the concrete slab (strength + thickness) can take the anchors
5. Keep full documentation for audit/acceptance: drawings, calcs, mill cert, engineer certification

We design and supply seismic-rated pallet racking to FEM 10.2.08 / EN 16681 and ANSI MH16.1, using DPT 1311 regional forces — with drawings and calculations certified by a civil engineer for government work and warehouses requiring inspection acceptance, including base plate, anchor design, load signs, and mill certificates.

Talk to our engineering team to develop your warehouse's seismic rack design — call 02-096-2118 or LINE OA @406rrgvm.

Summary

• Bangkok must consider seismic because its soft soil amplifies distant earthquake waves
• Use DPT 1311 for regional forces + FEM 10.2.08/EN 16681 or ANSI MH16.1/ASCE 7-22 for the design method
• Key differences: base shear, anchor/base plate for pull-out, cyclic bracing, row spacers
• Government work needs drawings + calculations + engineer certification + load signs
• Before buying: state location + weights + heights, and ask for certified drawings — not just a catalog

Seismic racking is not an unnecessary expense — it prevents the domino collapse that can destroy an entire warehouse in seconds.