# Shear Performance for Prestressed Concrete Hollow Core Slabs
## 1 Introduction  
To enhance user satisfaction and to meet the demands of the times, extensive efforts are being made to introduce multi-purpose flexible spaces in modern architectural structures. Structural members with long spans are essential for flexible structures, but larger cross-sections involve higher costs and increase the overall weight. As such, it is necessary to develop a rational structural system that remains lightweight.  
Compared to general reinforced concrete slabs, prestressed concrete hollow core slabs (HCS), members with hollow cores and more structurally efficient cross-sections, are widely used in Europe and North America as tendons in upper and lower layers to help achieve superior flexural rigidity and strength [1; 2; 3; 4; 5; 6; 7]. Figure 1 presents the manufacturing site of D, which manufactured the specimens used in this study. In the case of HCS, strands placed on a long-line bed of 90-180 m are jacked at once, and members are fabricated through extrusion with placing of high-strength, zero-slump concrete. This not only facilitates mass production, but also enhances overall quality of structures through the dense packing of concrete [8].  
HCS members, which are manufactured in factories and assembled on-site, have a short construction period and allow easy on-site management. They are widely used in structures requiring long-span floors such as distribution centers, discount stores and semiconductor factories. They are especially advantageous for long-span structures thanks to their reduced weight from the use of hollow cores [9; 10]. However, high strength concrete with low slump is placed without molds, and the mix is extruded while compacting. As such, the placement of transverse reinforcement is almost impossible [7], and structural evaluation is important at member ends where shear force is dominant because the introduction of prestress causes high stress concentration. In addition, the accuracy of the strength prediction for securing the structural safety of the prestressed concrete members are required.  
Due to these effects, a study [11; 12; 13; 14] has been conducted to reasonably predict the shear strength of prestressed concrete members. [PERSON] et al. [11] proposed a shear strength prediction formula that reflects the influence of shear span-to-depth ratio (\(a/d\)) on the shear strength evaluation of prestressed concrete I-beams by comparing the experimental results with previous studies. [PERSON] et al. [13] presented and validated a simplified mechanical model to make it easier for practitioners to use for shear design purposes. [PERSON] [14] proposed a practical method using finite element analysis to efficiently evaluate the section forces of HCS with openings.  
Using members manufactured by D, this study conducted shear experiments with cross-sectional height and presence of topping concrete as variables to evaluate the structural performance of HCS. Qualitative requirements of shear performance were experimentally verified by comparing the experimental results to analytical results derived based on design codes and the findings of previous studies.