###### Abstract  
Welded headed studs are used to connect steel girders and concrete slabs in steel composite bridges. However, environmental problems related to welded shear connectors have been reported, including noise and dust generation during the replacement and demolition of damaged or worn concrete slabs. To overcome these issues, demountable shear connectors that enable easy replacement of damaged or worn concrete slabs must be developed. However, conventional bolted shear connectors mainly use embedded nuts, which cannot be used in structures such as bridges because initial slip occurs and the stiffness and shear resistance strength are relatively low. To address these issues, this paper proposes a bolted shear connector that integrates the embedded nut part into the stud bolt and has a tapered shape at the bottom of the expansion column. For performance verification in regard to static shear strength and slip displacement, push-out tests were performed according to Eurocode-4, and the performance of the proposed stud bolt was compared to those of conventional welded headed studs and embedded nut-style bolted shear connectors. In addition, an analytical review was performed using the ABAQUS program for the 1/4 axisymmetric model of the push-out test. As a result of applying the material nonlinear model and the surface contact analysis, the load-slip displacement of each analysis model showed a tendency extremely similar to the experimental results. The proposed demountable bolted shear connector exhibited excellent shear performance and can be used as a satisfactory replacement for conventional welded studs because it meets slip displacement and ductility standards. steel composite bridge; welded headed stud; bolted stud; demountable shear connector; push-out test +
Footnote †: journal:  
the use of deicing chemicals, and slabs require replacement much sooner than steel girders. Because of the various problems that occur when slabs are replaced, there are sometimes cases in which entire bridges are demolished and rebuilt, including the girders, which still have sufficient remaining lifespans. Therefore, in terms of life cycle cost (LCC), the overall bridge lifespan can be increased considerably, and its economic feasibility can be greatly improved by replacing the slabs several times over the life of the steel girders. Precast concrete slabs have many advantages over cast-in-place concrete slabs, including quality management and shortened building time during construction; however, during the process of demolition and removal to rebuild the slabs, the worn slabs must be cut and crushed for removal, which is not advantageous. Generally, when replacing a damaged or worn concrete slab, the slab between the girders is firstly cut with a wheel saw or diamond wire saw and demolished. Then, the slab that is connected to the top of the girder, i.e., the concrete part that is integrated by the shear connector, is crushed with a breaker or water jet equipment and removed. The demolition process of precast slabs is the same as that of cast-in-place slabs because the slabs are connected to the welded studs at the steel girders by non-shrink mortar via a slab shear pocket. During demolition, a breaker is used to crush the part of the concrete slab that is linked to the shear connector, causing a lot of noise and fine dust, which increases secondary damage in urban areas. In addition, as the work continues for a long time, an extended period of traffic control is necessary until the reconstruction is complete, which inconveniences citizens and causes significant economic losses. When this work is performed, the welded studs can be bent or damaged by the impact of the breaker, and ultimately the slab must be rebuilt after cutting all the conventional studs and welding new studs. Using a water jet to perform crushing minimizes the damage to the shear connectors, but takes a long time and increases the cost.