Strain evolution of mechanical joints for L-shaped precast columns Part II: Application to a tall building

Abstract

This study succeeded in an experimental investigation of the authors’ previous studies in which L-shaped dry mechanical joints were developed and tested to demonstrate applicability to precast concrete frames. In their early study, the use of L-shaped dry mechanical joints assembling precast concrete frames was verified both experimentally, demonstrating all structural components at joint experimentally functioned well, supporting both cyclic and monolithic loads. In the present study, design recommendations and collateral benefits were provided to design tall building frames based on an extensive strain analysis, while improving joints using interior stiffeners to greatly enhance the structural performance of mechanical joints. How fast strains of joints are developed as deflections progressed was also explored based on rates of strain increase relative to deflection, while identifying degradation mechanism of mechanical joints (including rebars and steel sections attached to mechanical plates) that led to brittle failure modes. This study aims to provide design protocol for a 20-story apartment building with L-shaped precast columns spliced by mechanical plates. Beam-column joints were assembled by extended beam endplates, which were bolted to plates embedded in columns. A sufficient beam depth was determined by avoiding stress concentration exerted by extended beam endplates.

Keywords

• dry mechanical joint
• strain evolution
• irregular l-shaped precast column
• contact surface
• precast column splice