In many structural concrete applications, loaded areas are surrounded by steel reinforcement or additional concrete in order to triaxially confine the region. This confinement effectively increases the local bearing strength and ductility. However, this is typically accomplished at the expense of increasing steel congestion and/or providing an inefficient amount of additional concrete. One way of alleviating these complications may be by confining loaded areas with steel fiber reinforced concrete (SFRC). Provisions within ACI 318-11 allow for an increase in the effective bearing strength of concrete based on the ratio of the loaded area to the overall area. However, there has not been a study of the confining capability of SFRC when the loaded area is smaller than the surrounding area. The study presented in this thesis addresses this need.

The current research project examines the influence of SFRC on the bearing strength of triaxially confined nodal regions. As part of this evaluation, twenty-four 12..24-inch cylindrical specimens were loaded to failure through 6- and 3-inch diameter bearing plates. Experimental variables include transverse reinforcement ratios ranging between 0 and 0.80 percent, and steel fiber dosages between 0 and 1.5 percent by volume. Specimens were uniaxially loaded to failure while displacement and load data was recorded.