Center for Industries and Technology, Paris (Courtesy of Structurae.de)

CONCRETE SHELLS

Many thin concrete shells have been built around the world as large span roofs, but their use has gradually declined over the past few decades. This decline has been due mainly to the high cost of construction and removal of temporary formwork and associated falsework for concrete casting in the construction of a thin concrete shell. This labour intensive and costly process of construction, coupled with the increasing ease in analysing complex skeletal spatial structures offered by advances in computer technology, has made concrete shells much less competitive than they were a few decades ago.

 

Over the years, there have been several attempts aimed at eliminating the need for temporary formwork in constructing thin concrete shell roofs, but these have met with only limited success.

  • Precast concrete panels with in-situ cast joints

Requires the extra work of transportation to and assembly on site. Overall cost savings are limited.

  • Inflated membrane forms

Difficult to control the shape and thickness of the shell and the position of reinforcement.

Kresge Auditorium, MIT, Cambridge, Massachusetts (Courtesy of Structurae.de)
 
Kongresshalle, Berlin. (Courtesy of Structurae.de)

An excellent review of these attempts and other developments of thin concrete shell roofs has been given by Medwadowski (1998) who concluded that forming “remains the great, unsolved problem of construction of concrete thin shell roofs. Any and all ideas should be explored, without prejudice.”

The latest development in the forming of thin concrete shell roofs is the steel-concrete composite shell system (the COMSHELL roof) proposed by Teng (2001) which is believed to be a very promising solution to the difficult problem of forming.

 
  © Copy 1999-2005, Teng, J.G. all rights reserved.