Hydrogen embrittlement
Hydrogen embrittlement occurs as a result of exposure to hydrogen, for example, in the manufacture or processing of high-strength steels and titanium and aluminium alloys. It reduces the ductility and load-bearing capacity of affected materials, which can cause cracking or failure at below normal yield stresses.
Hydrogen embrittlement takes place when recently-produced, nascent hydrogen atoms diffuse into the metal. When load is applied, the hydrogen atoms migrate towards areas of high stress, and the resulting pressure causes sub-microscopic cracking. These cracks themselves become areas of high stress, and so the process continues and the cracks spread through the material, which can ultimately result in failure.
In November 2014, two large bolts fractured at the 47-storey, 737ft Leadenhall Building, popularly known as ‘The Cheesegrater’ because of its distinctive slanting profile, created to respect a protected sight line of St Paul’s Cathedral. A small part of one of the bolts fell from the fifth floor to the ground, but the area was not publicly accessible due to ongoing construction works and nobody was injured.
A third bolt then fractured but was captured by tethering which had been installed following the first two failures.
Investigations undertaken by contractor Laing O’Rourke and structural engineers Arup confirmed that the problem was limited to certain bolts. Tests concluded that the bolts had failed due to hydrogen embrittlement. Arup also confirmed that there was no adverse effect on the structural integrity of the building. However, a programme was undertaken to replace a number of bolts a precautionary measure.
In April 2019, Structural steelwork contractor Severfield released a trading update announcing that it had reached a final settlement with developer Leadenhall following “extensive negotiations”. Ref http://www.constructionmanagermagazine.com/news/severfield-settles-over-cheesegrater-bolts/
[edit] Related articles on Designing Buildings Wiki
- Brittle fracture.
- Corrosion.
- Degradation of construction materials.
- Failure of cast iron beams.
- Failure of metals.
- Graphitisation.
- Leadenhall building.
- Rust.
- Spalling.
[edit] External references
- Global Construction Review. Fear of failure: Why bolts on London’s Cheesegrater tower began to break. 16 January 2015.
Featured articles and news
Licensing construction in the UK
As the latest report and proposal to licence builders reaches Parliament.
Building Safety Alliance golden thread guidance
Extensive excel checklist of information with guidance document freely accessible.
Fair Payment Code and other payment initiatives
For fair and late payments, need to work together to add value.
Pre-planning delivery programmes and delay penalties
Proposed for housebuilders in government reform: Speeding Up Build Out.
High street health: converting a building for healthcare uses
The benefits of health centres acting as new anchor sites in the high street.
The Remarkable Pinwill Sisters: from ‘lady woodcarvers’ to professionals. Book review.
Skills gap and investment returns on apprenticeships
ECA welcomes new reports from JTL Training and The Electrotechnical Skills Partnership.
Committee report criticises UK retrofit schemes
CIOB responds to UK’s Energy Security and Net Zero Committee report.
Design and construction industry podcasts
Professional development, practice, the pandemic, platforms and podcasts. Have we missed anything?
C20 Society; Buildings at Risk List 2025
10 more buildings published with updates on the past decade of buildings featured.
Boiler Upgrade Scheme and certifications consultation
Summary of government consultation, closing 11 June 2025.
Deputy editor of AT, Tim Fraser, discusses the newly formed society with its current chair, Chris Halligan MCIAT.
Barratt Lo-E passivhaus standard homes planned enmasse
With an initial 728 Lo-E homes across two sites and many more planned for the future.
Government urged to uphold Warm Homes commitment
ECA and industry bodies write to Government concerning its 13.2 billion Warm Homes manifesto commitment.
From project managers to rising stars, sustainability pioneers and more.
Places of Worship in Britain and Ireland, 1929-1990. Book review.