Cracking is expected in the reinforced concrete flexural members and develops gradually under the interactions of several direct or indirect factors.
At this study, two parameters, compressive strength of concrete, sum of perimeters of steels were varied in a factorial experiment on rectangular reinforced concrete flexural members, and in addition to the practical condition, influence of axial force was considered.
Thirty beams were tested to failure to study the cracking behavior of flexural beams with axial force and analytical and experimental investigation of their flexural cracking. All test specimens were subjected to 4-points loading with axial force to produce a constant moment region between the loads.
Test results showed that the sum of perimeters of steels and the axial force had effects on cracking and crack propagation, and the compressive strength of concrete had no effects on. As axial force increased, crack spacing increased, while crack width decreased. And in condition of equal steel ratio, as the sum of perimeters of steels increased, number of cracks increased and consequently both crack spacing and crack width decreased.
Based on the test results, equation to predict crack spacings in reinforced concrete members with axial force was proposed
