Uplift force
An uplift force is any upward pressure applied to a structure that has the potential to raise it relative to its surroundings. Uplift forces can be a consequence of pressure from the ground below, wind, surface water, and so on.
Water pressure can exert an uplift force on a structure due to high rainfall, for example by causing clay soils to expand. This can be problematic if the upward forces are greater than the forces being exerted downwards by the structure. To overcome this risk, the structure must be appropriately designed to provide greater resistance against uplift forces, and also a drainage system to relieve the water pressure.
For more information, see Ground heave.
All roofs are subject to wind uplift, which will vary according to location, terrain, height, size, shape, exposure and so on. Wind uplift occurs when the air pressure under the roof is greater than the air pressure above it. This can be exacerbated during high wind, as air infiltration into the building can increase pressure below the roof, whilst the speed of wind over the roof surface can reduce air pressure above it, in much the same way it does over an aircraft wing. This can cause damage to the roof if the difference in pressure becomes too great.
'BS EN 1991-1-4:2005+A1:2010 Eurocode 1. Actions on structures. General actions. Wind actions' defines the methodology for calculating likely wind loads which then allow a roofing system to be appropriately designed.
[edit] Related articles on Designing Buildings Wiki
- Bearing capacity.
- Floor loading.
- Ground heave.
- Hurricane design considerations.
- Lateral loads.
- Limit state design.
- Moment.
- Racking.
- Roofing defects.
- Settlement of buildings.
- Subsidence.
- The design of temporary structures and wind adjacent to tall buildings.
- Types of structural load.
- Uniformly Distributed Load.
- Vibrations.
- Wind comfort simulations.
- Wind load.
Featured articles and news
Listed despite problems with its design.
Zen and the art of cycling exploration.
Design Council Homes Taskforce launched
To support government 1.5 million homes target within UK climate commitments.
The story of this knowledge quarter building.
In ecology, in hydrology, in biology and in architecture.
Creating environments that promote physical, mental, and social well-being.
UK cases of neutral current diversion
Research project looks for example contributions.
Overstocking and macro-economics cause a decline.
The 2024 update of the Common Assessment Standard
Demonstrating organisational capability’ to fulfil roles under the Building Safety Act.
56 recommendations for a better built environment
Published by the CIC ahead of the King’s Speech.
SkillELECTRIC Top 8 Competitors Named
in annual search for the UK’s best student electrician.
CIOB Diversity and Inclusion technical information sheet
Step-by-step guide on implementing D and I practices.
Conservation and the Indian City. Book review.
Reversibility in conservation ethics
Learning from painting conservation.
Where It's AT Podcast launched!
New CIAT Architectural Technology Podcast goes live.