Failure Behavior and Tension Stiffening of RC Tension Members

The tension stiffening effect is defined as the increase in stiffness in reinforced concrete member due to the stiffness provided by concrete between cracks.. If this is disregarded in analysis of reinforced concrete members, especially at the level of service loads, member stiffness may be underestimated considerably. This paper presents on the failure behavior and tension stiffening of RC tension members, based on the experimental results which were obtained from direct tension test with main experimental variables such as concrete strength, diameter and strength of reinforcement steel. The tension stiffening was analyzed from the load-displacement relationship by ACI code and the equation proposed by Collins & Mitchell. In summary, the effect of tension stiffening rapidly decreased as the rebar diameter increased, rebar strength increased and concrete strength increased. The effect of tension stiffening on RC member was biggest near the behavior of concrete cracking and decreased as the load closed to the breaking point. Thus, the tension stiffening should be considered for the precise analysis near the cracking load of concrete.