1. AISC N690: Appendix N9 Design of Steel-Plate Composite (SC) Walls By,
11/15/13
Design of Steel-Plate Composite (SC) Walls
By,
Amit H. Varma
University
Copyright, Amit H. Varma, Purdue Univ.

2. Outline Specification for Steel-Plate Composite Structures
11/15/13
Specification for Steel-Plate Composite Structures
Layout and Organization of N690 Appendix N9
Presentation Modules and Links
Ongoing Work
Copyright, Amit H. Varma, Purdue Univ.

3. Objective
11/15/13
Specification for steel-plate composite SC walls in safety-related nuclear facilities
Use with AISC N690 – LRFD code
Instead of ACI 349 code for concrete structures for nuclear facilities  but all topics covered
Specification for SC walls and associated connections
Copyright, Amit H. Varma, Purdue Univ.

4. Path Forward
Develop industry consensus standard for modular composite construction
NRC review standard and publish regulatory guide
AISC N690-12: Specification for design of steel structures for safety-related nuclear facilities
AISC TC12 – established ad-hoc sub-committee for modular composite construction
First Meeting Nov. 2006

5. Path Forward Sub-committee for modular composite construction
Has 20 active members
First Meeting Nov. 2006
Conducted a total of 164 meetings and numerous conference calls
Attendees include guests from a variety of institutions as well as international participation

6. Schedule Schedule for completion Ballot 1 – Nov. 2013
Ballot 2 – June 2014 with public review comments
Ballot 3 – Nov with public review comments
Ballot 4 – Jan with final public review comments
ANSI approved standard

7. Schedule
US NRC has started the review process using the public review ballot no. 2
Regulatory Guide based on N has been initiated, number allocated.
NRC position on the ANSI approved standard should come shortly after.

8. Layout and Organization of App N9
11/15/13
N Specification Additions
NA3 – Materials
NB2 – Loads and Load Combinations
Add F and H, and tread them like D and L (ACI 349)
NM2 – Fabrication, Erection, and Construction
Dimensional Tolerances
Minimum Requirements for Inspection of Composite Constructions
Copyright, Amit H. Varma, Purdue Univ.

9. Layout and Organization of App N9
11/15/13
N9.1 Design Requirements
N9.1.1 General Provisions
N9.1.2 Design Basis
N9.1.2a Required Strength
N9.1.2b Design for Stability
N9.1.3 Compactness Requirement
N9.1.4 Requirements for Composite Action
N9.1.4a Classification of Shear Connectors
N9.1.4b Spacing of Shear Connectors
N9.1.5 Tie Requirements
N9.1.5a Classification of Ties
N9.1.5b Required Tension Strength for Ties
Copyright, Amit H. Varma, Purdue Univ.

10. Layout and Organization of App N9
11/15/13
N9.1 Design Requirements (cont’)
N9.1.6 Design for Impulsive and Impactive Loads
N9.1.6a Definition of Loads
N9.1.6b Dynamic Increase Factors
N9.1.6c Ductility Ratios
N9.1.6d Response Determination
N9.1.7 Design and Detailing Around Opening
N9.1.7a Design and Detailing Requirements Around Small Openings
N9.1.7b Design and Detailing Requirements Around Large Openings
Copyright, Amit H. Varma, Purdue Univ.

11. Layout and Organization of App N9
11/15/13
N9.2 Analysis Requirements
N9.2.1 General Provisions
N9.2.2 Effective Stiffness for Analysis
N9.2.3 Geometric and Material Properties for Finite Element Analysis
N9.2.4 Analyses Involving Accidental Thermal Conditions
N9.2.5 Determination of Required Strengths
Copyright, Amit H. Varma, Purdue Univ.

12. Layout and Organization of App N9
11/15/13
N9.3 Design of SC Walls
N9.3.1 Uniaxial Tensile Strength
N9.3.2 Compressive Strength
N9.3.3 Out-of-Plane Flexural Strength
N9.3.4 In-Plane Shear Strength
N9.3.5 Out-of-Plane Shear Strength
N9.3.6 Strength Under Combined Forces
N9.3.6a Out-of-Plane Shear Forces
N9.3.6b In-Plane Membrane Forces and Out-of-Plane Moments
Copyright, Amit H. Varma, Purdue Univ.

13. Layout and Organization of App N9
11/15/13
N9.4 Design of SC Wall Connections
N9.4.1 General Provisions
N9.4.2 Required Strength
N9.4.3 Available Strength
Copyright, Amit H. Varma, Purdue Univ.

14. Flowchart: Design and Specs
11/15/13
Begin design of structure with SC walls
Check that SC section thickness, reinforcement ratio, faceplate thickness, steel and concrete grades satisfy the limitations of Section N9.1.1.
Check that applicable requirements of Section N9.1.1 are satisfied.
Copyright, Amit H. Varma, Purdue Univ.
Are the requirements of N9.1.1 satisfied?
Appendix N9 is not applicable. (Refer to Commentary for alternate methods) No
Yes
Continue

15. Flowchart: Design and Specs
Continue
11/15/13
Check that faceplate is compact (Section N9.1.3)
Provide composite action using shear connectors
Classify connectors as yielding or nonyielding type using Section N9.1.4a.
Check spacing of shear connectors using Section N9.1.4b
Copyright, Amit H. Varma, Purdue Univ.
Provide structural integrity using ties
Check tie spacing using Section N9.1.5.
Check tie spacing in regions around openings using Section N9.1.7.
Classify ties as yielding or nonyielding using Section N9.1.5a.
Ties contribute to out-of-plane shear strength of SC walls according to Section N9.3.5
Calculate minimum required tension strength for ties using Section N9.1.5b.
Continue

16. Flowchart: Design and Specs
Continue
11/15/13
Develop linear elastic finite element (LEFE) model according to Sections N9.2.1 and N9.2.3
Analyze LEFE model for load and load combinations from Section NB2.
Model openings using Section N9.1.7.
Model flexural and shear stiffness of SC walls using Section N9.2.2.
Loading due to accidental thermal conditions will be as per Section N9.2.4.
Model second-order effects using Section N9.1.2b
Copyright, Amit H. Varma, Purdue Univ.
Perform LEFE analysis to calculate design demands and required strengths.
Identify interior and connection regions using Section N9.1.2
Calculate required strengths for each demand type using SectionN9.2.5
Continue

17. Flowchart: Design and Specs
Continue
11/15/13
Design Process for SC Walls: Required strengths ≤ Available strengths
Calculate available strengths for each demand type using Section N9.3.
The sub-sections are:
Available uniaxial tensile strength using Section N9.3.1
Available compressive strength using Section N9.3.2
Available out-of-plane flexural strength using Section N9.3.3
Available in-plane shear strength using Section N9.3.4
Available out-of-plane shear strength using Section N9.3.5
Check available strength for combined forces using Section N9.3.6
Combined out-of-plane shear demands using Section N9.3.6a
Combined in-plane membrane forces and out-of-plane moments using Section N9.3.6b 
Copyright, Amit H. Varma, Purdue Univ.
Continue

18. Flowchart: Design and Specs
Continue
11/15/13
Design Process for SC Wall Connections
Select full strength or overstrength connection design philosophy, and
design force transfer mechanisms for connections as per Section N9.4.1.
Calculate connection required strength for each demand type in accordance with Section N9.4.2
Calculate connection available strength using Section N9.4.3
Check connection required strength ≤ connection available strength
Copyright, Amit H. Varma, Purdue Univ.
Check SC wall design for impactive and impulsive loads in accordance with Section N9.1.6
Continue

19. Flowchart: Design and Specs
Continue
11/15/13
Fabrication, Erection and Construction Requirements
Specify detailing for regions around openings using Section N9.1.7
Specify dimensional tolerances for fabrication of SC wall panels, sub-modules, and modules using Section N9.5
Copyright, Amit H. Varma, Purdue Univ.
Specify quality assurance/quality control requirements for SC walls in accordance with Section N9.6
End design of structure with SC walls

20. Presentation Modules Module 1: General Provisions, Requirements,
11/15/13
Module 1:
General Provisions, Requirements,
Limitations
Copyright, Amit H. Varma, Purdue Univ.
Module 2:
Analysis Requirements and
Recommendations
Module 3:
Shear Connectors,
Local buckling
Composite Action

21. Presentation Modules (Contd.)
11/15/13
Module 4:
Tie Bars
Design requirements
Out-of-Plane Shear
Module 6:
Design Interaction equations for combined forces and moments
Module 5:
Available Strength
Tension, Compression
Flexure, In-Plane Shear
Copyright, Amit H. Varma, Purdue Univ.
Module 7:
Connection Design

22. Public Access to Presentation Modules
11/15/13
Varma, A.H.* (2014). “Draft Provisions on Modular Composite Construction Under Consideration by AISC N690, Appendix N9.” Presentation to the Nuclear Regulatory Commission (NRC), Public Meeting.
Meeting announcement:
Meeting summary:
All slides and discussion notes from meeting below:
Copyright, Amit H. Varma, Purdue Univ.

23. Development of an AISC DG
11/15/13
Design Guide on SC Composite Walls
Work initiated: May 2014
First major submission for review: Oct. 2014
Second major submission for review: Jan. 2015
Third major submission for review: July 2015
Finalization of DG: Nov. 2015
Copyright, Amit H. Varma, Purdue Univ.

24. Past and Current Work
Testing of modular composite wall design for current nuclear plant designs
Full-scale tests to confirm design equations and performance
Scaled tests to confirm strength and ductility for earthquake loading
Full-scale tests for combined accident thermal and seismic loading
Confirmatory tests of connection behavior

25. Past and Current work
Numerical simulation of modular composite structure response to seismic events, accident thermal + seismic event (Fukushima type scenario),
Numerical simulation of modular structure response to aircraft impact
Experimental confirmation and numerical simulation of connection behavior, performance and failure modes

26. Current work
Development of connection strategies and technologies for modular composite construction
Sponsored by the DOE – NEET, Advanced Methods of Manufacturing program
Experimental testing
Numerical simulation
Development of design guidelines for:
SC wall-to-concrete basemat anchorage
SC wall-to-wall T and L connection
SC wall-to-slab connection

27. Current Work
Modular composite structures subjected to accident thermal conditions and seismic loading
Sponsored by DOE – NEUP Program, Advanced Methods of Manufacturing
Experimental testing
Numerical simulation
Development of design and analysis guidelines
Effects of accident thermal loading on in-plane shear behavior of SC and RC walls

28. Current Work
Design of modular composite structures for impulsive and impactive loading
Sponsored by the US NRC and DOE
Experimental testing in US ACoE facility
Numerical simulations
Development of design guidelines
Impulsive loading tests – conducted Oct. 2014
Missile Impact tests – 2015, 2016

29. Future Work
Use of stainless steel and other corrosion resistant systems in modular composite construction for SMRs
Use of curved walls in modular composite construction, particularly use of combined containment vessel and shield building
Effects of structure-soil-structure interaction in the design of modular composite structures

30. Putting the ‘M’ in SMRs Construction schedule & success
Various innovative and efficient designs
Project specific testing and analysis minimized
Development of ANSI approved AISC Specification and NRC regulatory guide
Outline of AISC N Supp. No. 1

31. Putting the ‘M’ in SMRs
Numerous testing, simulation, and design projects conducted at Purdue for current power plant designs using modular composite structures.
Current Research Projects, funded by US DOE and US NRC, at Purdue to facilitate modular composite structures for SMRs
Challenges overcome
Making modularity in construction a reality …