Title: Performance of short-grouted ductile reinforcing bar connections under varying design parameters
Date Published: November - December 2025
Volume: 70
Issue: 6
Page Numbers: 39 - 64
Authors: Baha’a Al-Khateeb, Jon Mohle, and Yahya C. Kurama
https://doi.org/10.15554/pcij70.6-01

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Abstract

This paper reports findings from a study that built on the results of previously tested precast concrete shear walls with nonproprietary, short-grouted corrugated steel duct connections for ductile energy-dissipa­tion reinforcing bars crossing horizontal joints. The investigation involved three new wall specimens constructed and tested under varying parameters, including the energy-dissipation bar size, wall base moment–to–shear ratio, wall thickness, axial (compres­sion) load ratio, and layout of the connection ducts and tie reinforcement in the wall cross section. A revised strut-and-tie model was developed to design the tie reinforcement and connection length. The specimens satisfied the American Concrete Institute’s Acceptance Criteria for Special Unbonded Post-Tensioned Precast Structural Walls Based on Validation Testing and Commentary (ACI 550.6-19) for lateral strength loss, probable lateral strength, and energy dissipation at the validation-level drift. Two specimens had concrete compression failure, and one specimen failed due to ductile fracture of an energy-dissipation bar inside a short-grouted connection. None of the specimens ex­perienced pullout of the energy-dissipation reinforcing bars, an outcome that demonstrates the high perfor­mance of the proposed grouted connections for use in high seismic regions. The walls were generally in good condition at the end of each test despite undergoing large nonlinear lateral displacements. An important detail in achieving this performance was the intentional unbonding of the energy-dissipation reinforcing bars over a length of three times the bar diameter inside the connection ducts, which limited the deterioration of concrete at the base of the wall.