Cyclic test on a precast reinforced concrete column-to-foundation grouted duct connection

Abstract

A full-scale specimen of a column-to-foundation grouted duct connection suited for buildings and industrial structures is tested in cyclic bending combined with axial compression. The positioning of the steel ducts along the sides of the column cross-section allows for using traditional reinforcement cages for the column, with longitudinal bars at both mid-side and corners of the cross-section. Splice length and amount of transverse reinforcement along the splice are defined based on Eurocode 2 provisions for laps of reinforcing bars.A total of 19 loading cycles are carried out, achieving a drift of 5.3% in correspondence of a degradation of 15% of the peak resistance. The shear slip measured at the column-foundation interface results to be smaller than 5% of the deflection. Conversely, to predict accurately the test results, the slip of the projecting bars within their ducts cannot be neglected. It is proposed to take account of this slip by introducing an apparent strain. For the tested specimen, the apparent strain turns out to be equal to the yield strain of the reinforcement. A comparison with a monotonic bending test, previously conducted on the same connection, shows a strongly smaller deformability when the loading protocol is cyclic.Hysteretic energy and drift ductility for the proposed connection are close to those concerning a cast-in-place specimen of comparable capacity, which was described in a recent paper.The test results show an over-strength of 1.4 and a gain in ductility of 1.8 compared with the design values of bending resistance and curvature ductility computed for the cross-section at the column-foundation interface.

Seismic behavior of precast reinforced concrete column-to-foundation grouted duct connections

“…Concerning column-to-foundation connections, solutions with longitudinal bars protruding from the foundations and anchored in the column and viceversa (i.e., from the columns to the foundations) were analyzed in literature. While the former connection was tested in several experimental campaigns (Belleri and Riva 2012;Popa et al 2015;Tullini and Minghini 2020;Seifi et al 2019;Fan et al 2020), the latter was little investigated. In 2012, Buratti et al tested one column with protruding rebars anchored in the foundations by grouted ducts, showing its overall satisfying behavior.…”

Experimental investigation on the post-fire cyclic behavior of grouted sleeve connections

“…The concrete cover is likely to crush under seismic action, leading to loss of protection and buckling of rebar. Many researchers studied seismic performance of precast structures with sleeves connections, including column-to-foundation connections [13][14][15][16][17][18] , beam-column connections [19,20] , column-to-column connections [21,22] and shear wall connections [23,24] . It was found that using sleeve connections in a precast structure could effectively prevent buckling of rebar and the sleeves connections had enhanced fire resistance when they were placed in the foundation [15,20] .…”

Failure Evolution Law of Reinforced Anchor System under Pullout Load Based on DIC

“…PCEs provide structures with higher material quality, better durability, reduced environmental impact, and increased work zone safety. e connection of these elements is typically done using fieldcast nonshrink cementitious grouts [1][2][3][4]. e grout material not only needs to exhibit enough strength, but it should also offer a good bond to the concrete element to ensure adequate stress transfer.…”