Abstract
Ultrahigh‐performance fiber‐reinforced concrete (UHPFRC) is an innovative material in the field of bridge engineering. With superior mechanical characteristics, this new material reduced the structural self‐weight and extended the span of modern bridges. A series of tests should be conducted to establish reliable design rules for UHPFRC structures. This paper aimed at determining the compressive behavior of UHPFRC for thin‐walled arch section design and a comparison was made with a normal concrete (NC) arch. Eighteen axial compression columns for arch section design and arches under asymmetric load were tested in this paper. Behaviors of the arches were assessed using various mechanical properties, including the failure pattern, load‐deflection relationship, strain analysis, and analytical investigation. A finite element model (FEM) considering the material and geometric nonlinearity was developed to predict the behavior of the UHPFRC arch. Results indicated that a wall thickness of 50 mm with stirrups effectively restrained instability failure of the thin‐walled compression columns. The cracking load and the ultimate load of the UHPFRC arch increased by 60% and 34%, respectively, when comparing with the NC arch. It showed the UHPFRC arch had higher load capacity and outstanding durability. The failure mode of the UHPFRC arch was similar to that of the NC arch, which belonging to the destruction of multihinges. However, the appearance of the plastic hinges was delayed, and a better elastic‐plastic performance was obtained when using UHPFRC. The analytical formula for calculating the ultimate load of the UHPFRC arch was derived with high precision by using the limit equilibrium method. The results of the FEM showed good agreement with test results, and they were able to predict the behavior of the UHPFRC arches.
Highlights
After years of research and practice, ultrahigh-performance fiber-reinforced concrete (UHPFRC) has made its way into the construction field
Tests of the failure characteristics and cracks of the UHPFRC arch and normal concrete (NC) arch were performed. Both the UHPFRC and NC arches failed by multihinges collapse mode, as shown in Figure 5. e tests showed that many tightly spaced cracks formed near the main cracks, and the appearance of plastic hinges in the UHPFRC arch was much later than those in the NC arch
Tests of the propagation of main cracks were performed at each loading step as shown in Figure 6. e rst crack occurred at the bottom slab of L/4 section. e rst cracking loads of UHPFRC and NC arches were 40 kN and 25 kN, respectively. e cracking load of the UHPFRC arch is 60% more than that of the NC arch. e Pu of the UHPFRC arch was 390 kN, and it was higher than that of the NC arch by 34%
Summary
After years of research and practice, ultrahigh-performance fiber-reinforced concrete (UHPFRC) has made its way into the construction field. Shi et al considered the influences of section dimension of the columns, reinforcement ratio, and steel fiber, tested the behavior of twenty-two UHPFRC columns under eccentric compression, and found the section thickness has the most significant influence on the bearing capacity [17]. UHPFRC compared to normal concrete (NC) without steel fibers has significantly higher strength and toughness. It can be successfully used for thin-walled members, but there are few experimental studies about the compressive strength of thin-walled components. E stability is the primary problem that should be considered in the design of UHPFRC thin-walled arches and columns. E objective of this research is to further understand the structural mechanical performance of the UHPFRC arch and make full use of material strength in UHPFRC structural design
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