# Effects of Grout Compactness on the Tensile Behavior of Ground Splice Sleeve Connectors
## 1 Introduction
[13] presented a simplified modeling strategy for seismic assessment of precast bridge columns that were connected to precast footings using GSS connectors. A computational model was developed and validated using three half-scale bridge subassemblies. The results from the proposed computational model were found to be in good agreement with the experimental results. The grout compactness has a great effect on the mechanical properties of the grouted splice sleeve, and thereby, the precast concrete buildings. Scholars have paid attention to developing the monitoring and detection methods for grout compactness and GSS [16; 17; 18; 19; 20; 21]. [PERSON] et al. [16] presented a stress wave-based active sensing approach using piezoceramic transducers to monitor the grouting compactness in real-time. [PERSON] et al. [17] employed the impact-echo method to study the grouting compactness of the grout sleeve. While other scholars paid attention to the mechanical properties of the GSS, [PERSON] et al. [18] studied the tensile behavior of 15 half-grouted sleeve connections, and thus, an analytical model was proposed to predict the ultimate tensile capacity of the connections. To improve the performance of GSS, [PERSON] et al. [19] developed a new type of grout-filled coupling sleeve, and 11 coupler specimens of four categories with embedment lengths from 7 to 7.5 times bar diameter were prepared and tested under tensile load to study the mechanical performance. [PERSON] et al. used the acoustic emission method to investigate the monotonic tensile behavior and quasi-static cyclic behavior of GSS connectors and the performance of reinforced precast concrete bridge assemblies connected by GSS [20; 21]. Twenty-four specimens were conducted by [PERSON] [22] to study the effects of spliced rebars with different diameters on the mechanics of GSS. The mechanical properties of different structural components, such as column, beam, and shear walls connected by GSS, were also studied in recent years, and the results showed that GSS could be an effective solution for the promotion of precast structures [23; 24; 25]. Overall, although both the detection methods of grout compactness and the study on mechanical properties of new GSS can greatly improve the performance of GSS and are beneficial to the application of grouted splice sleeves in practical engineering, there is no direct linking between them. Furthermore, the effect of the grout compactness on the tensile bearing capacity of GSS connectors has not been reported. The grout compactness has a great effect on the mechanical properties of the grouted splice sleeve. The authors also propose a method to calculate the tensile bearing capacity of the grouted splice sleeve with the grout compactness into consideration. The method can be used to determine whether reinforcing remedies or re-grout is required in the case of incompact sleeve grouting during construction. Experiments were conducted on four types of GSS that were subjected to monotonic tensile loads. They have compactness of 100%, 90%, 70%, and 50%, respectively. The bond-slip model describing the relation of rebar-grout was, thus, deduced by fitting the monotonic tensile test data, and the tensile capacity calculation method of GSS is further studied. The objective of this paper is two-fold: (1) to study the effect of grout compactness on the performance of GSS and (2) to propose an assessment method for the tensile bearing capacity of GSS in case of incompact grouting. The rest of the paper is organized as follows: Section 2 introduces the monotonic tensile tests of GSS with different compactness. An analytical method for the tensile bearing capacity of GSS is presented in Section 3. Section 4 draws the conclusions.