Steel Concrete Composite (SC) Modular Construction for Safety-Related Nuclear Facilities

1. Steel Concrete Composite (SC) Modular Construction for Safety-Related Nuclear Facilities Codes and Standards Future Work

2. Appendix N9 for AISC N690 • N9A – General requirements • Materials, welding, etc. • N9B –Minimum requirements for SC sections • Reinforcement ratio and plate thickness • Concrete thickness • Plate slenderness • Tie system requirements • Shear connector spacing and size

3. Appendix N9 for AISC N690 • SC specific failure modes • Prevented from governing design • N9B4 - Plate slenderness ratio to ensure yielding before local buckling (non-compactness) • N9B5 - Stud spacing and size to prevent interfacial shear failure from governing design strength • N9B6 - Tie system spacing and strength to prevent splitting failure of the composite section

4. Appendix N9 for N690 • N9C - Analysis Recommendations • Stiffness as a function of concrete cracking • In-Plane shear stiffness (pre and post-cracking) • Flexural stiffness (pre and post- cracking) • Cracked stiffness for accident thermal loading combinations • Recommendations for finite element modeling • Calculation of Design Demands

5. Appendix N9 for N690 • N9D – Design for axial tension demands • N9E – Design for axial compression demands • N9F – Design for flexural demands • N9G1 – Design for in-plane shear demands

6. Appendix N9 for N690 • N9G2 – Design for out-of-plane shear • Four cases: • (1) Tie system yielding or non-yielding • (2) Spacing less than thickness/2 or more • Account for size effects

7. Appendix N9 for N690 • N9H – Design for combined forces • Interaction equation for two out-of-plane shears • Interaction equation for tie systems acting in interfacial shear and axial tension • Interaction surface for SC walls subjected to combined in-plane forces and out-of-plane moments

8. Appendix N9 for N690 • N9J – Connection Design • Full strength connection design • Designed so that connection is stronger than weaker of connected walls • Ductile behavior ensured • Over strength connection design • Designed for 200% of seismic forces in combinations with other demands • Relies on overstrength to achieve HCLPF of 1.67 SSE

9. Appendix N9 for N690 • Connections can be designed using connector elements that are widely used • Rebars, dowel bars • Welding, base plates • Shear studs, shear lugs etc.

10. Future Work • Experimental evaluation of full-strength connections • SC wall-to-basemat connections • Experimental confirmation of joint shear strength • SC wall-to-wall joints • Experimental confirmation of SC wall to slab connections

11. SC Wall-to-Wall Joint • Experimental setups developed, specimens being designed SC Wall-to-Wall Joint

12. SC Wall-to-Wall Joint Analysis • Nonlinear analysis benchmarked to experimental results, and used to conduct parametric studies

13. SC Wall-to-Basemat Connections • Full strength connection will develop strength of SC wall, no failure in connection elements • Setup designed and built, specimen being designed

14. SC Wall-to-Basemat Connection • Specimens being designed, and different options being evaluated analytically Baseplate 5 - #6 @ 3.5” O.C. Rebar Lenton Rebar End Anchors

15. Future Research Needs • Effects of accident thermal loading on connection behavior and design • Effects of tornado and hurricane missile impact on SC walls (two-way shear strength) • Concepts, designs, and tests of SC floors. • Fire resistant design of SC floor slabs • Effects of penetrations and pipes on SC wall design strength

16. Future Research Needs • Benchmarked analytical approaches for evaluating behavior of complex SC designs • Evaluation of green options for concrete in SC walls • Effects of fabrication, erection, and construction related imperfections and tolerances on SC wall design • Inspection and monitoring plans • Damping ratios for SC systems