ABSTRACT
The design of a structure is based on the assumption of certain properties of the materials to be used. The main property is strength which should lead to a sufficient capacity to carry dead, imposed, and wind loads. The actual strength of a mate rial is a variable quantity which depends on variations in mix constituents, placing and compaction, hardening temperature, curing, and on the testing procedure; the bearing capacity of a structural component varies as function of material strength, placing of bars in a reinforced section, and geometry of the cross-section.
