Structural steel used in buildings must satisfy strength, ductility, and durability requirements, and therefore several field tests are conducted to assess its quality and performance at site conditions. These tests help engineers ensure that the steel supplied and erected conforms to design specifications and relevant codes, and that it will perform safely throughout the service life of the structure. One of the most common field tests is the visual inspection test. This is a preliminary but very important test carried out before and during erection. The steel members are visually examined for surface defects such as cracks, lamination, corrosion, improper rolling, or damage during transportation and handling. Alignment, straightness of members, proper dimensions, bolt holes, and weld preparations are also