ACI 318-19 Changes to the Concrete Design Standard-Shear Modifications

Video Transcription

Video Summary

The video discusses comprehensive updates in the ACI 318.19 code specifically focusing on shear provisions for one-way beams, slabs, and two-way slabs. Key changes involve addressing the "size effect" and "reinforcement ratio," noting that larger beams might not proportionally increase strength, a phenomenon now integrated into the code. Additionally, as the reinforcement ratio decreases, reductions in shear strength are observed. The updates unify wall shear provisions in seismic and non-seismic designs, incorporate spacing requirements for shear reinforcement, and address bidirectional shear in corners. Two-way slab equations are updated with considerations for size and reinforcement to ensure current standards align with recent research findings. For practical application, solutions like increasing structural thickness or reinforcement are suggested for meeting new requirements, ensuring practitioners maintain effective, safe designs. Other changes include a revised approach for calculating shear capacity and guidance for hanger reinforcement when framing beams into larger beams or girders. The presentation underscores the importance of these changes to accommodate evolving structural engineering needs, promoting safety and structural integrity in varied construction scenarios.

Keywords

ACI 318.19

shear provisions

one-way beams

two-way slabs

size effect

reinforcement ratio

seismic design

shear reinforcement

structural integrity