Girder
A girder is a large and deep type of beam that is used in construction. It is typically capable of longer spans and taking greater loads than a normal beam, and is often used as a main horizontal structural support for smaller beams, such as in bridge construction.
There are several different types of girder available depending on circumstances, and the load they are required to support:
- Smaller steel girders can be 'rolled' into the required shape. When girders become larger however, a standard rolled shape may not be available and a plate girder may have to be fabricated instead.
- A plate girder is typically an I-beam cross-section made up of separate structural steel plates which are welded, bolted or riveted together to form the deeper vertical web and narrower horizontal flanges of the beam. Plate girders are commonly-used for spans of up to 15m.
- A gantry girder is used for a gantry crane - typically consisting of two ‘A’ frames connected by a lattice cross member which straddles the work area. The lifting gear is suspended from the horizontal girder and can move along it on rails. For more information, see Types of crane.
- A box girder is fabricated from steel plates used to form a rectangular box. This resists torsion better than a plate girder and can be used when depth constraints mean a plate girder cannot be made deeper.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Designing sustainability and performance into buildings
Specifying and selecting sustainable resilient timber products.
Modifying wood to improve resistance to decay and movement.
A last minute, long look for built environment professionals.
The architecture of creative reuse. Book review.
Installing solar panels on listed structures.
Sustainable development global goals, history in progress?
"Unless we act now, the 2030 Agenda will become an epitaph for a world that might have been."
Mike Kagioglou FCIOB named CIOB President
'Sustainable Development Goals must be focus for construction'
BSRIA training; a look at what's on offer
From energy management to compliance training.
TESP video warns to beware of rogue trainers.
Highlighting the slippery tactics of non-approved providers.
New Building Safety Wiki launched
Boosting awareness and understanding of the new fire safety regime.
New playbook on AI in construction published by CIOB
How to get to grips with, and the best from AI.
Digital Construction Report NBS
BIM, cloud, off-site, immersive tech, AI, twins and sustainability.
ECA learning zone and industry focus video series
From updates and amendments to circular economy, emergency lighting and much more.
The Building People Communities Network
Celebrating and amplifying voices of the under-represented, this refugee week and pride month.
Pride of Place: queer heritage
Acknowledging and taking pride in LGBTQ histories.