A model for predicting the splitting bearing capacity of Fiber Reinforced Concrete elements under partially loaded areas

Concrete elements are frequently subjected to partially loaded areas; a typical example is represented by precast tunnel segments. In fact, during the excavation process, the hydraulic jacks of the boring machine exert, on the last assembled ring, high forces concentrated on small areas with respect to the size of ring joint. Similarly, when lining is embedded in ground, high hooping forces are transmitted through longitudinal joints, which present a contact zone smaller than the segment cross section. In both cases, spreading these loads into tunnel segments result in tensile transverse stresses which may cause splitting cracks. In the last decades, the growing desire to find more economic and sustainable solutions has driven enormous efforts in the tunnel industry to find new design solution such those based on Fiber Reinforced Concrete (FRC) or a combination of FRC and traditionally steel rebars. Research studies have already demonstrated the ability of fibers in controlling splitting crack phenomena. However, there is a lack of knowledge on reliable analytical approaches to quantify these benefits. The main aim of this paper is to develop a new model for determining the bearing capacity of FRC elements under partially loaded areas when splitting failure occurs. The analytical model herein reported allows a good prediction of the maximum loads exhibited by FRC prisms tested under high concentrated loads, whose data were selected from the literature.