Uniaxial behavior and constitutive model of reinforcement confined coarse aggregate UHPC

Axial Behavior of Reinforced UHPC-NSC Composite Column under Compression

“…Additionally, the specimens lost their load-carrying capacity owing to the large-scale spalling of NSC. The reinforced UHPC column exhibited brittle failure soon after achieving its peak load, which is consistent with the test results by Zeng et al (2020) [5]. For the composite column, the initial crack occurred on the UHPC surface at the peak axial load.…”

“…Figure 6 b shows the CTS at the peak confined stresses for all the composite columns, which was close to the ultimate tensile strain. For a cylinder consisting of a material with tension strength, which was much less than the compression strength, the essence of compressive failure is that the circumferential tensile stress at the edge achieves tension strength [ 5 , 13 ]. This conclusion is also supported by the CTS development in the composite column at peak strength.…”

“…At the peak confined strength f cc , the stirrup and UHPC cover provided the confining stress at the same time. At the peak confined strength, the stirrup strain was considered to have been subjected to the ultimate tensile strain of the UHPC, the thickness of the cover layer was ignored, and all UHPC materials achieved the ultimate tensile strength f tu [ 5 ]. Thus, f l can be calculated as follows: …”

“…Therefore, the advantage of high compressive strength has not been fully exploited. To extend the application of the compressive strength of UHPC, Zeng et al (2020) investigated the compressive behavior of full-scale reinforced UHPC columns, and proposed a strain-stress model for the reinforced UHPC columns [5]. The test results revealed that the tensile strength of the UHPC material contributed the most to its confining effect, while the confining effect from the stirrup was relatively small.…”

Behaviour of retrofited precast UHPC and Ni-Ti SMA column-to-foundation connection with CFRP wrapping layers

“…UHPC concrete has a compressive strength of at least 120 MPa at 28 days [14,15] and a flexural tensile strength up to 45 MPa [16]. Its cementitious matrix contains small metal fibres at a very high dosage rate of at least 1% by volume [15,17] which confers high ductility and reduces the need for transverse reinforcement [16,18,27,[19][20][21][22][23][24][25][26]. Its use in structures dissipates energy [28] and reduces concrete damage [18,29,30] as it delays spalling of the concrete cover and compression reinforcement buckling [11,12,30].…”