Dilation characteristics of confined concrete

✍ Scribed by Amir Mirmiran; Mohsen Shahawy

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 324 KB
• Volume: 2
• Category: Article
• ISSN: 1082-5010
• DOI: 10.1002/(sici)1099-1484(199707)2:3<237::aid-cfm32>3.0.co;2-2

✦ Synopsis

Con®nement of concrete enhances its strength and ductility by restraining lateral dilation. The accuracy of a con®nement model depends on how well it captures the dilation tendency of concrete. In recent years, external con®nement of concrete by ®bre composites has become increasingly popular for civil infrastructure applications. This includes ®bre-wrapping of existing columns or encasement of concrete in a ®bre reinforced plastics (FRP) shell. A total of 54-concrete-®lled FRP tubes were tested in uniaxial compression under displacement control mode. Full instrumentation of the specimens has allowed the variation of tangent Poisson's ratio for concrete to be captured. The dilation trend of con®ned concrete is shown to be a function of jacket stiffness. In steel-encased members, once steel yields, con®ning pressure becomes constant and the jacket renders itself ineffective in containing the dilation of concrete. On the other hand, for linear-elastic materials such as ®bre composites, a strain reversal occurs that results in containment of dilation. A method for predicting the dilation is developed that can be easily adopted in any active con®nement model. Moreover, a new con®nement model for FRP-encased concrete is discussed.