Construction of Concrete Shells Using Inflated Forms ACI 334.3R-05

Description

For centuries, arched and dome-shaped structures have efficiently enclosed large clear-span volumes. The strength of compound-curved surfaces allowed early builders to construct self-supporting thin-shell buildings from a variety of materials. Due to the tremendous amount of time and effort needed to create the desired shapes, construction of these thin-shelled structures sometimes spanned several decades.

Knowledge of the design and construction of thin-shellconcrete structures has greatly increased over the past 100years, both from research and practical experience. In thepast 40 to 50 years, the use of inflated forms has allowed shellsto be constructed more economically (South 1990). This newtype of construction process presents new challenges andconcerns. Safety measures and construction tolerances areaddressed in this report for many types of systems usinginflatable forms.

This report contains the lessons learned in the constructionof thin-shell concrete dome structures using inflated forms.As this method of construction continues to gain popularity,additional research is needed to increase understanding ofthe behavior of this type of shell so that inflated-form structurescontinue to meet adequate levels of safety and serviceability.

Included are construction procedures, tolerances, and designchecks to ensure that the finished structure meets adequatesafety and serviceability levels. This document focusesprimarily on inflated form thin shells using polyurethanefoam as part of the construction process. Many structures arebuilt using fabric forms where the concrete is applieddirectly to the form either from the outside or the inside.These general guidelines apply to all methods.