1 Side Shear Strength of Preformed Socket Connections Suitable for Vertical 1 Precast Members 2 Zhao Cheng, S.M.ASCE 1 and Sri Sritharan, Ph.D., M.ASCE 2 3 1 Graduate Research Assistant, Dept. of Civil, Construction, and Environmental Engineering, 4 Iowa State Univ., Ames, IA 50011. E-mail: zcheng@iastate.edu 5 2 Wilkinson Chair of Interdisciplinary Engineering, Dept. of Civil, Construction, and 6 Environmental Engineering, Iowa State Univ., Ames, IA 50011 (corresponding author). E-mail: 7 sri@iastate.edu 8 ABSTRACT 9 Use of precast substructure in Accelerated Bridge Construction (ABC) has been gaining popularity 10 due to its advantages over traditional cast-in-place (CIP) construction. When using vertical precast 11 members (e.g., columns and piles) in bridge substructure construction, they must be connected to 12 the adjoining members (e.g., bent cap, pile cap, and abutment) reliably. To accomplish this goal 13 and promote ease of construction, the preformed socket connection has been suggested. This 14 connection is established by inserting the vertical precast member inside a preformed socket in the 15 precast adjoining member and filling the socket with non-shrink, high-strength grout. Using 16 specimens that modeled the full-scaled connection interfaces, this paper experimentally evaluates 17 the side shear strength of preformed socket connections with various connection parameters. Test 18 results show that side shear mechanism in the preformed socket connections can provide 19 significant resistance, facilitating transfer of large vertical loads. This paper also includes 20 recommendations for the socket connections and appropriate stress limits. 21