421.2R-10 Guide to Seismic Design of Punching Shear Reinforcement in Flat Plates

During an earthquake, the unbalanced moments transferred at flat plate-column connections can produce significant shear stresses that increase the vulnerability of these connections to brittle punching shear failure. ACI 421.2R-10 Guide to Seismic Design of Punching Shear Reinforcement in Flat Plates provides recommendations for designing flat plate-column connections with sufficient ductility to withstand lateral drift without punching shear failure or loss of moment transfer capacity. This guide treats reinforced concrete flat plates with or without post-tensioning.

TABLE OF CONTENTS: 

• Chapter 1 Introduction: 1.1 General. 1.2 Scope. 1.3 Objective. 1.4 Remarks.
• Chapter 2 Notation and definitions.
• Chapter 3 Lateral story drift: 3.1 Lateral-force-resisting systems. 3.2 Limits on story drift ratio. 3.3 Effects of gravity loads on story drift capacity. 3.4 Design recommendations for flat plates with and without shear reinforcement.
• Chapter 4 Minimum shear and integrity reinforcements in flat plates.
• Chapter 5 Assessment of ductility. 
• Chapter 6 Unbalanced design moment: 6.1 Frame analysis. 6.2 Simplified elastic analysis. 6.3 Upper limit for Mu.
• Chapter 7 Design of shear reinforcement: 7.1 Strength design. 7.2 Summary of design steps 7.3—ACI 318 provisions 
• Chapter 8 Post-tensioned flat plates: 8.1 General. 8.2 Sign convention. 8.3 Post-tensioning effects. 8.4 Effective compressive stress fpc. 8.5 Extension of punching shear design procedure to post-tensioned flat plates. 8.6 Research on post-tensioned flat plates.
• Chapter 9 References: 9.1 Referenced standards and reports. 9.2 Cited references.
• Appendix A Verification of proposed minimum amount of shear reinforcement for earthquake resistant flat plate-column connections.
• Appendix B Verification of upper limit to unbalanced moment to be used in punching shear design.
• Appendix C Notes on properties of shear-critical section: C.1 Second moments of area. C.2 Equations for γv.
• Appendix D Design examples: D.1 General. D.2 Example 1 Interior flat plate-column connection. D.3 Example 2 Edge flat plate-column connection. D.4 Example 3 Corner flat plate-column connection. D.5 Example 4 Use of stirrups - Interior flat plate-column connection. D.6 Example 5 Interior flat plate-column connection of Example 1, repeated using SI units. D.7 Post-tensioned flat plate structure. D.8 Example 6 Post-tensioned flat plate connection with interior column. D.9 Example 7 Post-tensioned flat plate connection with edge column.
• Appendix E Conversion factors.