PSI - Issue 64

S. Kolemenoglu et al. / Procedia Structural Integrity 64 (2024) 857–868 Author name / Structural Integrity Procedia 00 (2019) 000–000

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stage tests. Five days after repair applications, the specimens were re-tested. The photos of the specimens after the first stage of the tests, removing process of damaged concrete and after repair applications are shown in Figure 4. No shrinkage crack was observed after the repair procedure of all specimens. 2.4. Material Properties This study mainly targeted the code-conforming RC columns. Therefore, material qualities were chosen in compliance with the current seismic design codes. The concrete mixture was determined to satisfy the mechanical properties of “C30” class concrete and the reinforcements were chosen as a “B420C” class deformed bars, which are included in Turkish Building Earthquake Code 2018 (TBEC 2018). Concrete compression strength was determined by uniaxial compression tests of 100mmx200mm cylindrical concrete specimens, which were kept under identical curing

Table 1. Test Matrix.

Axial load ratio n=N d /(A c f’ c )

Targeted damage condition before repair and corresponding damage level in Table 2 Failure (at least %20 decrement in base moment)

f’ c (MPa)

Repair method

Specimen name

R-27-1-0 R-27-1-1

-

Initiation of crushing (Damage Level I / Slight) Local crushing (Damage Level II / Moderate) Cover Spalling (Damage Level III/ Moderate)

Structural Mortar

27% (N d = 1050 kN)

38.8

R-27-1-2

Structural Mortar

R-27-1-3

Structural Mortar

Table 2. Damage Condition Classification. Damage Level JBPDA 2015

View from Reference Specimen

Damage Level for Experimental Program

TCIP 2024

ATC 145

Residual cracking < 0.2 mm

I (Initiation of crushing)

Hairline residual cracking (<0.2 mm)

Slight

0.2 mm < residual cracking < 1 mm

Residual cracking < 0.5 mm

Local crushing & spalling 0.5 mm < residual cracking < 3 mm

Local crushing & 1 mm < residual cracking < 2 mm

II (Local crushing)

Non-hairline residual cracking & spalling

Moderate

Significant crushing & exposure of rebar & residual cracking > 2 mm

Slight buckling < s/20 or 1.5 cm & residual cracking > 3 mm

III (Cover Spalling)

Buckling, crushing of core concrete, residual deformations, bar rupture

Buckling, crushing of core concrete, residual deformation

Buckling, crushing of core concrete, residual deformation

Heavy

s: the distance of buckling rebar to the center