Masonry Bracing

Life Safety Considerations During Construction of

Masonry Walls

FACTORS TO CONSIDER

Who is responsible for wall bracing?

Engineer General Contractor Masonry Contractor Qualified Person

CODE REQUIREMENTS 1926.706(b) All masonry walls

greater than 8 feet in height must be braced to prevent overturning and collapse,

Unless adequately supported so it will not overturn or collapse

Bracing must remain in place until permanent supporting elements of the structure are in place

Code Requirements

THEN WHAT? Code does not give

direction for spacing of braces Vertical Horizontal Additional Height

Code Requirements

LIMITED ACCESS ZONE (L.A.Z.) 1926.706(a)

Some common misconceptions: Limited Access Zones do not take

the place of wall braces, Wall braces do not take the place

of L.A.Z, Both are required

Test Wall Construction

Test Wall Construction 8 in. Lightweight Block 2 - #4 Horizontal Rebar spaced

4 ft. on center #5 Vertical Rebar spaced 4 ft.

on center Coil Loop Inserts with ¾” coil

bolts 2000 psi grout at rebar

locations Grouting in pours of 8ft.

Test Wall Construction

Coil Loop Inserts installed around a vertical rebar and placed behind a horizontal rebar as shown

Picture of coil here

Wall Brace connection

Test Wall ConstructionWhy a coil loop insert? Past industry practice has been anchor

bolts set in grout and then attach brace Grout needed to set for 12 hour minimum Leaves window of exposure of 12 hours or

more This method allows braces to be installed

before the grout is placed in block Life safety issue 35 mile wind protection Won’t show where braces were installed

after removal

Base Connection

Must be evaluated by a Qualified Person

Concrete block deadweight Test wall deadweight 3400 lbs

Slab connection

Anchor bolt set in concrete

Base Connection

Slab Deadmen

Base Connection

Wedge Anchor

Tang Bolt

Super Bolt

Spacing of Braces:

Vertical Placement

Code requires Wall Braces above 8 ft.

No direction as to spacing

Spacing of Braces:Recommended Horizontal Spacing: No direction from the code 20 foot spacing 10 ft from end of wall or control joints Works with 20 foot lengths of rebar Allows for scaffolding, trucks,

forklifts, and other equipment to work between braces

Creates a safe and efficient environment for workers

Spacing of Braces:

What does all of this do?

Creates a crisscross rebar mat in the wall

Uses materials already in wall

Adds minimal additional cost

Types of Braces

Wood not recommended

Concrete tilt braces or approved equal

Note: Braces must stay in place until roof components are installed.

Intersection of Other Walls

Wall intersections may substitute for braces

Pilasters may help in spacing braces farther apart

Connection to existing walls

Adjoining BuildingsRequires scaffold & braces on

same side of wall Creates additional hardship on

contractors Alternative method – use taper

bolts or she bolts connecting new wall to adjacent structural wall Require adjacent building

Owner’s permission

Adjoining Buildings

Adjoining Buildings

Moving braces from one side to another

Sometimes necessary due to work by other trades

Remove braces sequentially from one side of wall to the other

MUST attach additional braces before removing existing

Adding additional coil loops may be necessary: Will help facilitate the moving of braces

while providing a good level of safety for personnel

Our Nemesis –

WIND:

Our wind standard: 35 mph

Call the Weather Service Obtain regional wind chart of

historical data Need to know daily wind

speeds Daily wind directions Procure a wind meter

Establish an Action Level

At winds speeds above 25 mph: Check that braces

are secure Consider evacuation

of scaffold and surrounding areas

Our unbraced, grouted wall deflected less than an inch at 35 mph and fell at a wind speed in excess of 60 mph

In Conclusion This is NOT intended to be used as a

complete approach to bracing walls ALL relevant factors MUST be

considered Site conditions Weather conditions Wall design Construction sequence Property lines Any other relevant conditions or factors

References Masonry Bracing Task Force

(Funded by OR-OSHA Grant) Task Force Documentation

Test Report Video