Investigating the effect of compressive reinforcement on the flexural strength of sections based on ACI 318-05

According to pre-2002 editions of the ACI 318 Regulations, in normal bending sections, it is not necessary to use a compression reinforcement before reaching the maximum tensile reinforcement and it is not necessary to use it to help the bending strength of the non-economical section. By changing the way the flexural strength reduction coefficient is determined since the 2002 editions, this coefficient is reduced for sections that are stretched out of the controlled area and entered into the transition zone. In such cases, the use of compression reinforcement can return the section to the controlled area by tension, and indirectly by increasing the value of the reduction coefficient of resistance, it has a significant effect on the flexural strength of the section, which justifies its use economically. . In this research, the above issue is examined and evaluated and suggestions for how to use the armature optimally are presented.