Mechanical interlock
Structural Fixings for Ductwork Systems BG 10/2010, By Glenn Hawkins, Published by BSRIA in 2010, states in relation to the working principles of structural fixings: ‘Keying (or mechanical interlock) is the working principle of screws and undercut anchors. As a self-tapping concrete screw is driven into a pre-drilled hole, it keys into the structural base material. An undercut anchor keys into the base material as it is tightened to a specified torque. Hole depth, hole diameter and anchor embedment depth are key criteria that affect performance of these fixings. Keying is also one of the key working principles of direct fastening systems, which drive hardened nails into the structural base material using specialist power tools. Direct fastening also uses bonding and clamping principles too.’
--BSRIA
[edit] Related articles on Designing Buildings
Featured articles and news
From medieval scribes to modern word art.
Electrical contractors welcome crackdown on late payment and push for clean energy.
Cyber Security in the Built Environment
Protecting projects, data, and digital assets: A CIOB Academy TIS.
Managing competence in the built environment
ITFG publishes new industry guide on how to meet the ICC principles.
The UK's campaign to reduce noise pollution: Mythbusting, articles and topic guides.
Setting Expectations on Competence Management
Industry Competence Committee.
New Scottish and Welsh governments
CIOB stresses importance of construction after new parliament elections.
The sad story of Derby Hippodrome
An historic building left to decay.
ECA, JIB and JTL back Fabian Society call to invest in skills for a stronger built environment workforce.
Women's Contributions to the Built Environment.
Calls for the delayed Circular Economy Strategy
Over 50 leading businesses, trade associations and professional bodies, including CIAT, and UKGBC sign open letter.
The future workforce: culture change and skill
Under the spotlight at UK Construction Week London.
A landmark moment for postmodern heritage.


















