steel concrete composite (sc) modular construction for safety- related nuclear facilities codes and...

Steel Concrete Composite (SC) Modular Construction for Safety-

Related Nuclear Facilities

Codes and Standards

Future Work

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

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

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

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

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

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

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

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.

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

SC Wall-to-Wall Joint

• Experimental setups developed, specimens being designed

SC Wall-to-Wall Joint

SC Wall-to-Wall Joint Analysis

• Nonlinear analysis benchmarked to experimental results, and used to conduct parametric studies

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

SC Wall-to-Basemat Connection

• Specimens being designed, and different options being evaluated analytically

5 - #6 @ 3.5” O.C. Rebar

Baseplate

Lenton Rebar End Anchors

Future Research Needs

1. Effects of accident thermal loading on connection behavior and design

2. Effects of tornado and hurricane missile impact on SC walls (two-way shear strength)

3. Concepts, designs, and tests of SC floors.

4. Fire resistant design of SC floor slabs

5. Effects of penetrations and pipes on SC wall design strength

Future Research Needs

6. Benchmarked analytical approaches for evaluating behavior of complex SC designs

7. Evaluation of green options for concrete in SC walls

8. Effects of fabrication, erection, and construction related imperfections and tolerances on SC wall design

9. Inspection and monitoring plans10. Damping ratios for SC systems