A doubly-bolstered construction with appropriate rebar spacing will withstand both tensile and compressive stresses, supplying it a high tolerance for strain for its life span. Inappropriate spacing, even though slight, will bring about a reduction of your structure’s integrity. In case you are on a personal relationship, like at http://archerpizsg.blogkoo.com/little-known-facts-about-upper-continuous-rebar-support-chart-16631035