- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 03 Mar 2020
Shell construction technologies
Shells are structures enclosing buildings with smooth continuous surfaces (such as vaults and domes). There are shallow and deep shells. Typically, upper parts develop compression and the lower parts develop tension.
Shells are usually built with increasing thickness from the crown towards the base. This is due to the thrust force that becomes larger towards the base. However, there are internal stresses that are created due to this increase in thickness.
The principal components of masonry are the masonry elements and mortar embedment. Masonry elements include naturally available stones, dressed stones from quarries, made-up bricks of sun dried clay and burnt bricks in kilns. Mortar in masonry has developed from primitive mud, natural bitumen to a mixture of lime and sand and cement mortar.
From a structural point of view masonry is a homogenous material. The strength of the masonry is limited by its weakest joints. Its load-carrying capacity largely depends on the mortar strength. The allowed stresses in masonry are categorised into compressive axial, compressive flexural, tensile flexural and shear.
Modern thin concrete shells derive from the ancestry Roman vaults. Concrete has some advantages compared to masonry shells. Concrete is a manufactured material that acts well in large scale works. It can bear compressive and shear forces many times greater than brick and stone masonry. Concrete finds applications in thinner and larger structures. The smoothness and homogeneity of concrete make it a monolithic material. Concrete can carry tension, compression, shear, bending, and torsion as compared to brick or stone masonry.
Barrel shells are one-way arched 'slabs' spanning between two parallel longitudinal supports. There are long barrels and short barrels. Long barrels behave like a beam, while for short barrel shells the top surfaces act like a series of adjacent arches.
These are shells that project outward from key points of support. Cantilevered thin shell structures create a sense of an illusion of floating. Just like a cantilevered beam, a cross-section of thin cantilevered shell displays zones with compression and tensile stresses which are transferred to supports by reinforcements and concrete masses.
 Related articles on Designing Buildings Wiki
Featured articles and news
Discover the Winchester Mystery House.
Priorities for rail in the Midlands and the North.
Examining renovate-operate-transfer arrangements.
Proactive measures to secure property during extreme times.
Safety guidance from BSI released; comments requested.
Scour can make river currents structurally damaging.
Indoor environmental quality looks at air quality and other wellbeing factors.
A procurement method associated with Public Private Partnerships.
Infrastructure can use digital technology to encourage human growth.
Robotics and the construction industry.
ECA comments on CLC's three-phase recovery plan.
Their diplomatic and architectural history.
The origins of the six volume series.
Built to defend British waters, only to serve as pirate radio stations later.
Wellbeing to influence mix of home and office based working.
An introduction to cobotics.