Deadman Guy Footing Guide
A deadman guy footing resists pull from a guy wire. The force tries to drag, lift, and rotate the buried block. A good estimate checks each action separately. It also compares the results with safe soil capacity. This calculator helps plan early sizes before final engineering review.
Why the Check Matters
Guyed supports often fail because the anchor moves before concrete breaks. Weak soil, shallow cover, or a small projected face can reduce resistance. Water can also lower friction and passive pressure. The footing should therefore have enough mass, enough face area, and enough embedment. The anchor rod must also carry the full guy tension.
What the Tool Estimates
The tool resolves guy tension into horizontal and vertical parts. Horizontal pull is compared with passive soil resistance. Vertical uplift is compared with concrete weight and soil cover weight. Sliding resistance includes passive soil resistance and base friction. Bearing pressure is checked against the allowable value. The tool also estimates a minimum steel rod diameter from allowable stress.
Good Input Practice
Use the maximum service guy tension expected at the anchor. Include wind, ice, construction loads, and any tensioning allowance. Measure the guy angle above the ground. Use conservative soil values when field data is unknown. Granular soil usually performs better than loose fill. Clay strength can change with moisture. Increase the safety factor for uncertain ground.
Reading the Results
A safety ratio above the selected factor is usually preferred. Values near one need attention. Increase width or depth to improve passive resistance. Increase length, width, height, or cover to improve uplift resistance. Better soil, drainage, and compaction can also help. The result table shows demand, capacity, and status for each check.
Important Limits
This calculator is a planning tool. It uses simplified rectangular block assumptions. It does not replace a local code review. It does not model frost heave, cyclic loading, corrosion, group effects, or rock anchors. Final anchor design should be checked by a qualified professional. Site testing is strongly recommended for critical structures.
Practical Notes
Keep the block aligned with the guy direction. Place steel hardware centrally. Protect rods from corrosion. Backfill in layers. Compact evenly. Keep drainage paths open around the anchor zone.