The behaviour of sleeve connection with spiral reinforcement and additional longitudinal bar under direct tensile load

Abstract

One of the important precast concepts is all the precast elements must be connected for the stability. Therefore, the connection systems of the precast concrete structure must be designed in such a way that its structural performance is equivalent to that of a monolithic concrete structure. In most cases, conventional bar lapping system shows detailing problems due to its long development length, particularly for large diameter steel bars to be embedded in precast concrete structures. As an alternative, splice sleeve connector can be utilized as connection system, splicing reinforcement bars extruded from structural element to ensure continuity among them. However, the existing splice sleeve connectors in the market are proprietary and patented by foreign companies resulting in the high cost of adoption, particularly in Malaysia Therefore, this research aims to remedy this by developing a new splice connector that is tailored to the needs of the Malaysian construction industry. This new splice connector utilizes a simple transverse reinforcement which consists of R6 spiral bar and welded with four additional longitudinal Y10 bars. This project report summarizes the experimental programmed and also the performance of the proposed splice connector under axial tension. The influence of several parameters of the proposed connector is identified. These parameters include the infill material, reinforcement bar embedment length, spiral diameter and configuration of the additional bar. The experiments examined the tensile strength as well as the failure mode of the connectors. The result shows that the proposed sleeve connector of 33 mm and 58 mm diameter, with at least 200 mm of embedment length could provide a satisfactory structural performance that can develop the fracture capacity of the reinforcement bar. Thus, show that the connector could achieved the required strength with less required embedment length as compared to the conventional lapping system.