Small wind / Buyer questions
Structure and civil works
Should earthquake and extreme wind effects simply be added for foundation design?
The short answer
Do not simply add independently maximized earthquake and extreme wind effects. The governing design framework determines which hazards and accompanying actions belong together, with what factors and probabilities. The foundation still needs assessment for every applicable case, but combining unrelated maxima is not a substitute for a consistent load-combination basis.
Distinguish demand from ground response
Wind and earthquake cases can impose different force directions, durations and dynamic effects. Earthquake assessment can additionally involve soil strength change, settlement or lateral spreading. Those ground consequences are not captured merely by adding a seismic horizontal force to a wind moment.
The support model must therefore match the hazard being assessed. A soil spring appropriate to one condition may not describe another after significant ground response.
Avoid incompatible factor and sign conventions
Check whether the tower loads already include factors and which permanent or variable actions accompany them. Downward dead load may improve uplift resistance while increasing another structural demand, so selecting a convenient maximum cannot replace case-specific assessment.
Likewise, positive and negative seismic directions should be treated according to the applicable method. A scalar sum can conceal changes in contact, anchor tension or sliding direction that matter to the foundation.
Agree a complete design-case schedule
The structural and geotechnical reviewers should identify the applicable local framework, hazard inputs and required combinations. Ask which cases govern bearing, sliding, overturning, structural strength and movement, and whether seismic ground effects require separate measures.
Retain this basis with the exact tower and turbine configuration. A general international FAQ cannot set globally applicable combination factors or certify compliance. If seismic uncertainty changes the foundation concept, resolve it before treating an ordinary wind-only foundation proposal as a completed design.
Sources
Examples are illustrative. Confirm product-specific performance, compatibility and supply scope in the applicable documents.