Short answer: for ground-mounted PV, wind usually governs the frame, because the structure is light and the panels catch wind. Earthquakes matter most below and between the frames: foundations in soft or liquefiable soils, slopes, connections, and anything heavy such as inverter skids, carports and ballasted roofs. In Myanmar, design to the National Building Code’s seismic values, check both load cases, and avoid building across active fault traces.
On 28 March 2025 a magnitude 7.7 earthquake ruptured the Sagaing Fault for about 420 km through central Myanmar. Several of the country’s solar plants lie in the same dry zone, from Mandalay and Meiktila to Minbu in Magway.
Key numbers
- A station near the fault recorded peak ground accelerations of about 1.07 g vertical and 0.63 g horizontal; the surface rupture averaged 2.7 m of offset, up to 5.6 m.
- At a solar plant near Thazi, about 15 m from the fault trace, researchers measured up to 2.2 m of displacement in a deformation zone about 20 m wide.
- For Mandalay, the Myanmar National Building Code 2020 gives maximum considered earthquake values of about SDS 1.20 g and S1 0.70 g, as cited in published studies of the earthquake.
1. Why wind usually governs the frame
Seismic force scales with weight; wind force scales with area and tilt. A ground-mounted array is light for its area, as this rough comparison shows:
| Item | Value per m² of panel |
|---|---|
| Module weight (about 30 kg on 2.6 m²) | about 12 kg |
| Steel at 40 t/MW, about 4,600 m² of modules per MW | about 9 kg |
| Horizontal seismic force at 1.2 g, no reduction | about 0.25 kN |
| Wind pressure at 35 m/s, net coefficient 1.0–1.5 | about 0.75–1.1 kN |
Our own order-of-magnitude illustration. Even with the full Mandalay design acceleration and no response reduction, wind on the panels is three to four times larger. The structure must still be checked for both load cases, but the frame members are rarely sized by earthquake. See our steel per MW guide for weight figures.
2. Where earthquakes do decide the design
| Element | Seismic risk | Design response |
|---|---|---|
| Foundations in river plains | Liquefaction of loose saturated sand; settlement and tilting | Geotechnical investigation; longer piles through liquefiable layers; avoid shallow pads on loose sand |
| Hillside sites | Slope failure and rockfall | Slope stability check; drainage; keep rows back from cut edges (see our hillside checklist) |
| Fault crossings | Metres of ground offset that no structure can resist | Map active traces; set back from the fault; segment rows and cables so damage stays local |
| Connections and bracing | Bolt loosening, brittle welds, vertical shaking | Ductile connections, locking fasteners, continuous load paths |
| Inverters, transformers, battery containers | Heavy, high centre of gravity, can slide or overturn | Anchor to foundations designed for seismic forces; flexible cable entries |
| Carports and rooftop arrays | Larger mass at height; ballasted arrays can slide | Full seismic design; anchoring or restraint for ballasted systems |
3. Codes and loads for Myanmar
- Myanmar National Building Code 2020 (MNBC): Part 3 (structural design) is based on ASCE 7 and ACI 318 and has applied to engineered structures since November 2020. A 2025 edition adds practice from the Mandalay earthquake; confirm which edition the owner requires.
- Site class: soil category changes the design spectrum. Soft alluvial sites along the Irrawaddy and Sittaung valleys amplify shaking.
- Wind: use the MNBC basic wind speed for the site; coastal Rakhine and the Ayeyarwady delta are cyclone-exposed.
- Corrosion: inland dry-zone sites are usually mild; coastal and delta sites need heavier coating (see our galvanizing guide).
4. A checklist for a Myanmar PV structure
- Geotechnical report with liquefaction assessment and pile load tests.
- Active fault map of the site, with set-backs agreed.
- Structural calculation covering wind and seismic combinations to MNBC, with the governing case stated.
- Pile or foundation design for uplift, lateral load and liquefaction where relevant.
- Connection details: bolt grades, locking method, slotted holes for thermal movement.
- Seismic anchorage for inverter stations and transformers.
- Inspection plan after any significant earthquake: pile heads, bracing, bolts and cable trays.
FAQ
Do solar mounting structures need seismic design?
Yes, both wind and seismic cases must be checked. For light ground-mounted arrays, wind usually governs the frame, while seismic design matters most for foundations, heavy equipment, carports and rooftop systems.
Is Myanmar’s dry zone a high seismic area?
Yes. The Sagaing Fault runs through it, and published hazard studies put Mandalay, Sagaing and Bago among the highest-hazard areas in the country.
Can a solar plant be built across a fault?
It should not be, if the trace is known. Surface rupture in 2025 offset the ground by metres. Where a site is close to a fault, set rows back and segment the layout so damage stays local.
Are trackers riskier than fixed structures in earthquakes?
Trackers have long torque tubes and mechanical drives, so differential ground movement affects them more. On sites with soft soils or nearby faults, fixed structures are simpler to design and repair.
How we help
Our structures plant near Kunming designs ground-mount and hillside structures to project loads, including wind and seismic cases, and supplies the calculation report with each design. Send us the site location, soil report and the code edition your owner requires.
Sources: UNOSAT and published field studies of the 28 March 2025 Mw 7.7 earthquake; studies of the surface rupture recorded at a solar plant near Thazi (2025, including arXiv 2505.20494); Myanmar National Building Code 2020, Part 3, and MNBC values for Mandalay as cited in Nature-family publications on the earthquake; national probabilistic seismic hazard studies for Myanmar (2023); industry guidance that wind governs most ground-mounted PV racking; SEAOC PV1 on rooftop arrays. The load comparison and checklist are our own engineering guidance. Related: fixed vs tracker, all mounting systems.