PSI - Issue 44

Michele Angiolilli et al. / Procedia Structural Integrity 44 (2023) 870–877 M. Angiolilli et al./ Structural Integrity Procedia 00 (2022) 000 – 000

872

3

Nomenclature E cm , E s Young’s module o f concrete and steel rebar, respectively f c, f ctm

compression strength of concrete and tensile strength of concrete yielding strength of steel rebar and ultimate strength of steel rebar

f y, f u

Tensile energy fracture

G I

f

h height of the RC specimen (from the bottom to the head column) V, V max shear force measured at the head column (applied force during the experiment) and the maximum one γ c, γ s Density of concrete and steel rebar, respectively Δ lateral displacement of the head column ε sy , ε su Deformation in correspondence of yielding strength and ultimate strength of the steel rebar, respectively ε LVDT Axial strain of the LVDTs installed to the joint θ Angular rotation under load of the column chord of the test module with respect to the beam chord (Δ/h) ν c, ν s Poisson’s coefficient of concrete and steel rebar, respectively 2. Experimental program A full reinforced concrete beam-column joint was constructed and tested for this study. The specimen represented the exterior beam-column joints subassembly isolated at the mid-points of members of a multi-storey concrete frame subjected to lateral loads. Fig. 1 shows the dimensions and reinforcement details of the specimen. In particular, beams had a cross-section of 300 x 500 mm2 and extended 2,000 mm from the column face. The cross-section of the columns was 300 x 500 mm2 and the total column height was 3,200 mm. A 300 x 500 mm2 transversal beam extending 300 mm from the column face was also realized to better replicate the real geometry of existing RC frames.

Fig. 1. Dimensions and reinforcement details of the RC specimen and details of the steel bars for the different concrete members.

Four steel rebars measuring 24 mm in diameter were disposed as longitudinal reinforcement on both the two short sides of the column, whereas two bars of 24 mm in diameter plus three bars of 20 mm in diameter were used as longitudinal reinforcement (both on top and bottom position) for the beams. The reinforcement of the short transversal beam consisted of four bars measuring 16 mm in diameter, one at each of the corners. Transversal reinforcement for both columns and beams consisted of 10 mm in diameter and steel stirrups spaced 100 mm. Stirrups were not inserted in the joint space, which was finally characterized by the absence of any shear reinforcement. The concrete used for casting specimens was normal weight concrete manufactured with Portland cement (type I), sand, and stone with a maximum size of 20 mm.