Construction-friendly ductile shear joints for precast concrete panels

Abstract

The scope of this paper is the shear capacity of in-situ cast joints between precast concrete panels. Current practice with vertical lowering of the wall panels experiences difficulties in the assembly phase, since the traditional U-bar connection requires an overlap in a horizontal plane to allow for the mounting of a vertical locking bar. Where limited space is available bending and subsequent straightening of the U-bars are required to assemble the adjacent panels, a procedure which imposes substantial ductility requirements on the reinforcement as well as some manual workload. This paper introduces a construction-friendly design with U-bars overlapping in the same plane as the panel itself. The design allows for a trouble-free vertical lowering of the panels without pre or post processing of the preinstalled reinforcement loops. Furthermore, an overall more ductile behavior of the joint is obtained. The solution is tested in a push-off experimental setup and the influence of important geometric parameters of the keyed shear joint is investigated. The first peak load carrying capacity is assessed using plasticity models, and the failure modes are identified by the use of digital image correlation. The upper bound models produce satisfactory results capturing the experimental tendencies and predicting the mode of shear failure in the shear keys.

Experimental Evaluation of Precast Concrete Walls with High-Tension Bolted Vertical Joints for Enhanced Ductile Behavior

“…To address these vulnerabilities, the S-PWR employs a widened joint slit (20 mm) and an increased transverse reinforcement ratio (0.31%). Compared to previous experimental studies involving similar PC wall joints [4,20,21], the transverse reinforcement ratio represents a significant increase, ranging from 14.81% to 121.43%, exceeding the typical range for such applications. The estimated shear stress corresponding to nominal shear strength for the S-PWR joint is 0.82 MPa, which is 14.81% to 121.43% higher than S-CIPW serves as the reference specimen for evaluating the performance of the PC wall with the proposed vertical joint.…”

Study of shear behavior of grouted vertical joints between precast concrete wall panels under direct shear loading

“…The grout contribution for shear resistance of keyed joints depends on the tensile strength of grout rather than the compressive strength . To eliminate the clashing of joint reinforcement, construction‐friendly reinforcement configuration was also studied . Also, the behavior of T‐connection (connection between exterior and interior wall panels) between precast panels were studied using U‐bars by Rossley et al and commercially available loop boxes by Jorgensen et al…”

Research of Forces in Vertical Key-Joints of a Large Panel Building in the Process of Its Construction

“…В связи с увеличением индустриального строительства в Индии поиск новых решений для устройства стыков сборных элементов затронул в том числе и шпоночные стыки с тросовым петлевым армированием [7][8][9]. Обширные экспериментально-теоретические исследования проведены исследователями из Дании [10][11][12][13][14].…”