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Course Sponsor
California Expanded Metal Company
263 North Covina Lane City of Industry, CA 91744
Phone 425-591-4174
E-mail [email protected]
Web www.cemcosteel.com
www.sureboard.com
Course Number
cem05c
Credit for this course is 1 AIA HSW CE Hour & 1 PDH
© Ron Blank & Associates, Inc. 2014
Designing with Shear Walls for Low
to Midrise Construction
An American Institute of Architects (AIA)
Continuing Education Program
Approved Promotional Statement:
Ron Blank & Associates, Inc. is a registered provider with The American Institute of
Architects Continuing Education System. Credit earned upon completion of this program
will be reported to CES Records for AIA members. Certificates of Completion are available
for all course participants upon completion of the course conclusion quiz with +80%.
Please view the following slide for more information on Certificates of Completion through
RBA
This program is registered with the AIA/CES for continuing professional education. As
such, it does not include content that may be deemed or construed to be an approval or
endorsement by the AIA or Ron Blank & Associates, Inc. of any material of construction or
any method or manner of handling, using, distributing, or dealing in any material or
product.
Course Format: This is a structured, web-based, self study course with a final exam.
Course Credit: 1 AIA Health Safety & Welfare (HSW) CE Hour
Completion Certificate: A confirmation is sent to you by email and you can print one upon
successful completion of a course or from your RonBlank.com transcript. If you have any
difficulties printing or receiving your Certificate please send requests to
Design professionals, please remember to print or save your certificate of completion after
successfully completing a course conclusion quiz. Email confirmations will be sent to the
email address you have provided in your RonBlank.com account.
An American Institute of Architects (AIA)
Continuing Education Program
Approved Promotional Statement
Ron Blank & Associates, Inc. has met the standards and requirements of the Registered
Continuing Education Program. Credit earned on completion of this program will be reported
to RCEP. Certificates of completion will be issued to all participants. Complaints regarding
registered providers may be addressed to RCEP at 1015 15th Street, NW, 8th Fl.,
Washington, DC, 20005. Web site: RCEP.net.
Registered Continuing Education Program
Understand how to design with shear walls for low to midrise
construction. The components, location, test standards,
advantages and disadvantages, as well as what should be
considered when specifying shear elements are illustrated in this
course.
Course Description
Upon completion of this course the Design Professional will be able to:
• Explain what shear is
• Describe what a shear wall is
• Explain the main components of a shear wall
• Show where shear walls should be located
• List what types of forces shear walls resist
• Explain where shear walls direct lateral forces
• Describe what the test standards are for
• Explain the methods and systems providing shear values
• Express the advantages and disadvantages of each type of shear
method
• Explain what Architect, Engineer, and Specification professionals
consider when specifying shear elements
Course Objectives
What is Shear and Shear Walls
Shear is an action or stress resulting from applied forces that
causes or tends to cause two contiguous parts of a body to
slide relatively to each other in a direction parallel to their
plane of contact.
What are the Functions of a Shear Wall?
Shear Walls
• Provide lateral Strength to resist horizontal earthquake or
wind forces placed upon the structure
• Provide lateral Stiffness preventing excessive movement in
the roof or floors above
• Resist two types of forces:
– Shear forces
– Uplift forces
• Transfer horizontal forces to the next element in the load
path below them
– Other shear walls
– Floors
– Foundation walls
– Slabs
– Footings
View of Lateral Input/Activity
This Building Needed MORE Shear Strength!
Seismic event in California prior to the building code updates
that now exist.
Nationally Published Zones
Components Providing Horizontal and Vertical
Transfer of Shear Forces
• Uplift devices (hold-downs/straps/bolts)
• Framed shear walls
• Steel reinforced concrete columns, walls
• Prefabricated shear assemblies
• Brace Frames
• Moment Frames
Three Main Components Providing
the Strength in a Framed Shear Wall
• Framing Members – Studs – Beams – Posts
• Sheathing/Bracing Materials – Sheet materials
• Plywood/OSB • Steel sheet • Composite shear panels • Drywall/cement boards
– Bracing • Interior brace frame (tube, stud, or plate) • Cross bracing/strapping
• Fastener (size, pattern, frequency, and method) – Nails – Screws – Welds
Composite Sheet Steel Shear Panels on Cold
Formed Steel Framing
Composite Sheet Steel Shear Panels on Cold
Formed Steel Framing
Composite Sheet Steel Shear Panels on Cold
Formed Steel Framing
Composite Sheet Steel Shear Panels in
Cold Formed Steel Studs
OSB Shear Panels
on Wood Framing
Composite Sheet Steel Shear Panels
on Wood Framing
Main Components of Poured Concrete
• Steel Reinforced Concrete – (simple or “caged” metal
rebar)
• Post Tension
• Concrete
– Thickness
– Compressive Strength
– Tensile strength
– Cure time
Steel Reinforced
Concrete Shear Walls
Where Are Shear Walls
Typically Located
• At Floor level of all structures
• Symmetrically on exterior and/or interior walls
• Placed in relation to strength and stiffness required to
accommodate load paths based on span-width ratios and
vertical load
Code Approved Test Standards
• Shear Walls and Lateral Control Devices
• Reverse Cyclic Testing Method
• SPD-Sequential Phased Displacement
• CUREE-Consortium of Universities for Research in Earthquake Engineering
• Requirements for Testing/Reporting/Performance
• ICC Evaluation Service
• IAPMO Evaluation Service
• Additional Local City Requirements
• Los Angeles-LARR/LA Research Report
• New York-MEA/Mechanical Engineering Approval
• Dade County Florida/Miami Dade Approval
Test Equipment For Cyclic Test
Materials and Methods - Testing Equipment
Cyclic Test Rack
Another Rack View/Two Story
Cyclic Positive/Negative Loop
Typical Methods For Accommodating Shear
• Plywood / OSB sheathing
• Flat strap “X brace or cross bracing”
• Prefabricated Shear wall Assemblies
• Steel Sheet Independently
• Corrugated Sheet Metal
• Concrete Shear Wall
• Steel Braced Frame/Moment Frame
• Composite Steel Sheet with Wallboard or Substrate
sheathing attached
Plywood/OSB Sheathing
• Standard thickness approved 7/16” to 15/32” thick Plywood/OSB
• Full height/or multiple pieces with required blocking, attached with approved fasteners at required spacing per engineer of record and approved plans and specifications
• Advantages
– Material readily available
– Fasteners readily available
– Easy to handle, cut, install
– Minimal STC increase – (entire wall covered)
Plywood/OSB Sheathing
Disadvantages
• Combustible (additional fuel and path for fire)
• Susceptible to mold, rot, termites, etc…
• Nails “overdriven” reducing the effective shear values
• Unnecessary excess material and labor required to “furr out” wall to match sheared portions for installation of finish drywall or plaster
• Categories of building not approved using these materials:
– Type II non-combustible
– Type III modified non-combustible
– Assisted living require more employees in case of fire/Added costs of employees to qualify for exemption to use wood based products
Cold Formed Steel Framing
OSB for Shear Panel (Rare)
OSB Shear Panels
on Wood Framing
OSB Shear Panels
on Wood Framing
Flat Strap “X or Cross Bracing”
• 6” typical steel flat stock
• Gusset plates (locate at corners)
• Advantages
– Material readily available
– Relatively low cost materials
– Small amount of materials used
Flat Strap “X or Cross Bracing”
Disadvantages
– Labor to first install gusset plates on all corners
– Labor to install straps (corner to corner)
– Build up of gusset plate, fasteners heads, and flat strap on top of one another
– Low shear value
– Ability to retain tension
• Difficult to install straps and retain tension
• Once wall “loaded” straps tend to buckle in unsupported spans
– Additional furring required to “hide” build up
– No penetrations, cutouts (doors or windows), or obstructions can go through straps
Picture of X-Bracing
• Prefabricated frames or formed steel
• Built to height, width, and strength requirements per E.O.R.
• Can be multiple pieces welded or fastened together
• May be single formed piece of material
• Advantages
– Strength
– Relatively quick install
– Less field labor to install
– Reduced number of fasteners required
Prefabricated Shear Wall Assembly
Prefabricated Shear Wall Assembly
Disadvantages
• Rigid causing issues with uneven foundation/floors
• Obstruction for MEP’s inside wall
• Obstruction for penetrations (doors, windows, etc…)
• Expense of prefabricated materials
• Shipping costs
• Field modifications are labor intense and costly
Pre-Fabricated Shear Walls
Prefabricated Shear Walls
Steel Sheet Shear Panel
• 22 Gauge steel sheet applied to wall framing
• Advantages
– Material readily available
– Non-combustible
– Thin requiring no additional furring of wall
– Provides backing
• Disadvantages
– Difficulty installing and keeping tension; Without proper
tension steel will buckle when loaded
– Build up of fasteners required for installing just the sheet of
steel
– Additional labor to install first steel then drywall sheets
– Strength reliant upon tension during install.
– Handling of materials
Sheet Steel Used as Shear Panel
with Difficulty Keeping Tight
Sheet Steel Used as Shear Panel with
Difficulty Keeping Tight
Corrugated Metal for Shear Panel
Corrugated metal panel installed with ribs perpendicular to studs
Advantages
• Stronger than Plywood/OSB
• Non-Combustible
• Material readily available
Disadvantages
• Build up on wall requiring additional furring for the entire length
of wall for wallboard
• Bends of corrugation make it less stable than flat sheet
• Labor to first install sheet of steel then additional labor to install
wallboard
• Penetration cut outs difficult due to depth of corrugations
Corrugated Test Panel at UC Berkeley
2007 Before Test
Results of Corrugated
Steel Shear Cyclic Test
Concrete Shear Walls/Shafts
Poured reinforced concrete shear walls
• Advantages
– Continuous rebar/cables throughout floors
– Weight eliminates significant “hold-down” requirements
– Building shear can be carried throughout, without framed shear walls
– Non-combustible
– High STC value
• Disadvantages
– Very expensive labor and materials to construct
– Job schedule slow down
– Penetrations very difficult/expensive
– Obstructions in design layout (less flexibility in design and changes)
– Increased weight of the overall building.
– Shear system must stand independent from any framing attached. (Entirely different performance characteristics)
Concrete Steel Reinforced
Bearing/ Shear Wall
Steel Braced Frame/Moment Frame
• Prefabricated steel I-beam and tube steel braced frames
• Built to height, width and strength requirements per engineer of record and approved drawings
• Can be multiple pieces welded or bolted together
• Advantages
─ Strong
─ Relatively quick to install
─ Less field labor to install
─ Reduced number of fasteners required
Disadvantages
• Very rigid with inability to conform with irregular concrete base
• Obstruction for MEP’s
• Obstruction in cavity if braced frame design
• Obstruction for windows, doors, etc.
• Very expensive system, with very little adjustment possible
• Significant point load in concrete deck/more concrete and steel required
• Cost to deliver is higher due to huge amounts of air-per-truck
• Costs to erect very high and very dangerous for workforce (Cranes/trucks/etc.)
Steel Braced Frame/Moment Frame
Steel Braced Frame/Moment Frame (1st level)
Steel Braced Frame/Moment Frame – Moving
Upward (Significantly Higher Labor Costs)
Composite Steel Sheet With Bonded
Gypsum/Substrate Wall Sheathing
• 22 Gauge Steel sheet laminated to any variety of gypsum or
non-structural substrate board product for Shear
• Requirements of Use
– Material made to each job requirements on height / 3
week lead time if special length requested
– Additional labor required to cut and install penetration
holes (New metal cutting saws and drill bits available)
– Additional labor to install and additional fasteners when
higher loads are required. (New collated screw-guns
available)
Composite Steel Sheet With Bonded
Gypsum/Substrate Wall Sheathing
Advantages
• Increased strength over plywood, sheet steel, and x-bracing
• Use any type, thickness, and variety of gypsum/cement based
wallboard
– Accommodate different wall designs and types of exposure
– May be used interior application
– May be used exterior application
– May be used as Structural substrate
• One step application installing shear element, fire rated protection,
and finish drywall
• Reduction of labor to install first shear element and then finished
product
Composite Steel Sheet With Bonded
Gypsum/Substrate Wall Sheathing
Advantages (cont’d)
• Improved fire resistance
• Improved STC ratings (when entire wall covered)
• Flexibility in design
• Provides backing (wall fixtures or second layer of drywall), abuse,
impact, and blast resistance
• Engineered system/ICC and all national approvals
• Non-combustible
• Insect proof
• Mold resistant
• .027 steel thickness/requires no additional furring required on rest of
wall
• No surface irregularities
• Hurricane impact resistant
Composite Steel/Gypsum Being Prefabricated
in Panel Shop for Delivery
Composite Steel/Gypsum After Installation
No Slack in Steel Sheet 30% Higher Strength
Composite Steel/Gypsum Stacked To Maximum
Limits of Code 65’ High Performance
• 22 Gauge Steel sheet laminated to 1/8” thick substrate
• Requirements of Use
– Material is made to each job’s requirements on height – 3 week delivery if special length requested
– Additional labor required to cut and install penetration holes (New metal cutting saws and drill bits available)
– Additional labor to install and additional fasteners when higher loads are required. (New collated screw-guns available)
Composite Steel Sheet and
Non-Structural Substrate
Composite Steel Sheet and
Non-Structural Substrate
Advantages • Increased strength over
plywood/OSB
• Can be used interior application
• Can be used exterior application
• Can be nailed on without concern of “over-driving” nails; providing
consistent values
• Improved fire resistance
• Improved STC ratings (when entire wall is covered)
• Flexibility in design
• Engineered system
• Insect proof
• Steel sheet is mold resistant
• Limited buildup with no additional furring required on rest of wall
• Eliminate excess plywood
• Reduction in material costs
• Requires only single 2 x bottom plate on all wood framed shear walls
• No surface irregularities
Composite Steel/Medium Density Fiber Board
Installed on Wood Framing With Nails
Composite Steel/Medium Density Fiber Board
Installed on Wood Framing Tight and Strong
Composite Steel/Medium Density Fiber Board
Installed on Cold Formed Steel Water Resistant
Design Considerations
Provide the basic information needed to assure that wood and
cold-formed steel Structures include the following information:
• Products are properly identified
• Buildings are specified and designed in accordance with
current building codes and industry recommendations
• Buildings are constructed per plans and industry standards
Composite Steel/Gypsum or
Medium Density Fiber Boards
Some additional applications are:
• Backing for wall mounted fixtures
• Superior Fire resistance for 1 and 2 Hour
• Shaft wall for mechanical ducts
• Projectile resistance (Hurricane Zones)
• Blast and Ballistic resistant walls
• Future floor and roof diaphragms
These Are The Results When
We Are Surprised By Nature
Without The Necessary Lateral Control,
Shear Will End Like This!!
Composite Steel/Gypsum Helped
This Design Hold Together
The Design Professional will now be able to:
• Explain what shear is
• Describe what a shear wall is
• Explain the main components of a shear wall
• Show where shear walls should be located
• List what types of forces shear walls resist
• Explain where shear walls direct lateral forces
• Describe what the test standards are for
• Explain the methods and systems providing shear values
• Express the advantages and disadvantages of each type of
shear method
• Explain what Architect, Engineer, and Specification
professionals consider when specifying shear elements
Course Summary
Course Sponsor
California Expanded Metal Company
263 North Covina Lane City of Industry, CA 91744
Phone 425-591-4174
E-mail [email protected]
Web www.cemcosteel.com
www.sureboard.com
Course Number
cem05c
Credit for this course is 1 AIA HSW CE Hour & 1 PDH
© Ron Blank & Associates, Inc. 2014
Designing with Shear Walls for Low
to Midrise Construction