Concrete is a structure that very weak in tension and need additional material to enhance their structural capacity. In 18<jats:sup>th</jats:sup>century, concrete have been recognized as structure that very weak in tension [. Thus, concrete need additional supporting material that can improve the tension capacity. Because of the steel is very good in tension, the steel bar was embedded in concrete at the tensile stress area to obtain the full capacity of the steel bar as reinforcement.
