ABSTRACT
Concrete structures are difficult to evaluate using theoretical models. These models require precise definitions of material properties, support conditions, and the stiffness of individual members. All of these are difficult to define for concrete structures. Other than compressive strength, test data on material properties are often not available, and when such data are available, they are likely to exhibit considerable scatter. Support conditions are not easily defined, and the stiffness of a cracked concrete member can be difficult to determine with any precision. For most structures, the fact that theoretical models cannot predict structural exact behavior is not a problem. The use of proper safety factors and years of experience
structures, theoretical evaluation is inadequate. Structures with suspected design or constructions flaws, damaged or deteriorated structures, or with unusual design features require a performance evaluation.
