Analysis of Bond Characteristics between Concrete and Deformed Bar by Meso-Scale Analysis

Abstract

This research was carried out in order to evaluate the bond characteristic between concrete and deformed bar in Macro level by meso-scale analysis using Rigid Body-Spring Model (RBSM). In the analysis, lugs of deformed bar were modeled considering the geometry. By the meso-scale analysis using the stress-strain relationship obtained from the tests in macro-scale, it was possible to understand the development of the internal cracks around the lugs as well as the development of the cracks and the bond behavior in macro-scale. Moreover, it was investigated the effect on the bond behavior of the lug spacing and the stiffness of the bar. As the results, the lug spacing was influence factor and the stiffness of the bar did not influence to the bond behavior.

Mesoscale simulation of bond behaviors between concrete and reinforcement under the effect of frost damage with axisymmetric Rigid Body Spring Model

“…Bolander and Saito introduced truss reinforcement elements as well as polyhedron concrete elements and they applied the RBSM approach to analyze concrete and reinforced concrete beams [24]. Muto et al adopted 2D reinforcement elements by configuring the outline of ribs and simulated uniaxial pulling-out test with specimens of long embedment length [25]. Tension stiffening was successfully observed in their simulation and the effect of several parameters were discussed.…”

“…1. For normal and shear springs of mortar-reinforcement (bond) interface, the values of stiffness are assumed same as those for mortar according to Muto et al [25]. It should be noted that for circumferential springs, the values of stiffness for mortar-reinforcement (bond), mortar-mortar, mortar-aggregate (ITZ) and aggregate-aggregate interfaces are calculated using Eelem and velem of mortar.…”

“…where θ and ci are constant values. For shear springs of mortar, ITZ and bond interface, the ideal plastic performance is assumed when local shear strain is small [25,26]. Whereas the shear stress transfer will decrease when shear sliding becomes big and the attached length of two elements is significantly reduced.…”

Investigating the anchorage performance of RC by using three‐dimensional discrete analysis

“…After reaching its strength in tension at f t , the stress in the springs is assumed to decrease linearly to zero at the maximum crack width w max (assumed to be 0.003 mm, see Figure 2(a)). The shear spring is assumed to behave in an elastic-plastic manner (Figure 2(c)), with a yield strength computed from equation (1) (adopted from Muto et al (2004), Figure 2…”

“…After reaching its strength in tension at f t , the stress in the springs is assumed to decrease linearly to zero at the maximum crack width w max (assumed to be 0.003 mm, see Figure 2(a)). The shear spring is assumed to behave in an elastic‐plastic manner (Figure 2(c)), with a yield strength computed from equation (1) (adopted from Muto et al (2004), Figure 2(b)). Here, ∅=37° and c = f t (1+tan ∅): Equation 1 For regions within 1D from the reinforcement surface, the concrete constitutive model for the normal spring is modified to account for interfacial transition zone between the reinforcement and the concrete (Salem and Maekawa, 2004).…”