Experimental Program

The experimental program features six precast concrete wall specimens based on a prototype structure. Five specimens will have hybrid reinforcement details and one “emulative” control wall will utilize only mild steel reinforcement (no PT steel) across the horizontal joints. The primary hybrid wall test parameters will be wall length, mild steel moment ratio, concrete confinement, and panel openings.

The experiments will be conducted at 0.4-scale, which satisfies the minimum scaling limit of ACI ITG-5.2. Another requirement of ACI ITG-5.2 is that the specimens are constructed using a minimum of two wall panels unless the prototype structure uses a single panel for the full height of the wall. In accordance with this requirement, the longer wall specimens (lw=20 ft at full scale) will feature two panels: the lower panel representing the base panel and the upper panel representing the 2nd through 4th stories. The upper story wall panels can be modeled as a single panel since no gap opening is expected at the joints between these panels. The shorter specimens (lw=12 ft at full scale) will be modeled using a single panel over the entire wall height. The lateral load will be applied at the resultant location of the 1st mode inertial forces for each specimen.

The test specimens are designed to satisfy the validation-level drift, θwm, specified by ACI ITG-5.1. Each specimen will be tested to failure (within equipment limits), which is expected to occur beyond θwm due to the low-cycle fatigue fracture of the energy dissipating mild steel reinforcement. This is a desirable failure mode for the walls since the presence of multiple reinforcing components crossing the critical base joint provides redundancy in the ultimate behavior of the structure. Crushing of the confined concrete may occur after the fracture of the energy dissipating reinforcement. Other potential failure modes for the test specimens, which have been suppressed through design, include the fracture of the PT strands, shear slip along the horizontal joints, and shear failure of the wall panels.

More details on the experimental program as well as pre-test analytical predictions for Specimen 1 can be found here. Additional papers discussing the measured behavior and analytical modeling of Specimen 1 can be found here.

The design calculations, production drawings, and casting photographs for Specimens 1, 2 and 3 can be found below.

Specimen 1:

Design Calculations
Production Drawings (1) (2)
Casting Photographs

Specimens 2 and 3:

Specimen 2 Design Calculations
Specimen 3 Design Calculations
Production Drawings

Specimen 4:

Design Calculations
Production Drawings (1) (2)

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