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Historic Preservation - Technical Procedures

Spectitle:

Installing Steel Bar Anchors In Brick Walls With Cementitious Grout

Procedure code:

0415001R

Source:

Jacob Weinberger Us Courthouse, San Diego, Ca

Division:

Masonry

Section:

Masonry Accessories

Last Modified:

02/24/2012

Details:

Installing Steel Bar Anchors In Brick Walls With Cementitious Grout



INSTALLING STEEL BAR ANCHORS TO REINFORCE UNREINFORCED BRICK WALLS


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on reinforcing brick
         masonry walls by installing anchor bars into core drilled
         holes.  Such action may be required due to seismic
         considerations of a project.  This procedure involves the
         following:

         1.   Core drill holes into walls for installation of bar
              anchors.

         2.   Remove existing brick to form cavities for access
              to connect the anchors to the structure of the
              building.

         3.   Provide and install threaded reinforcing bar
              anchors in the core drilled holes.

         4.   Embed the anchors in cementitious grout pumped into
              the core drilled holes.

    B.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   General Protection (Surface and Surrounding)

         These guidelines should be reviewed prior to performing
         this procedure and should be followed, when applicable,
         along with recommendations from the Regional Historic
         Preservation Officer (RHPO).

1.02 REFERENCES

    A.   American Society for Testing Materials (ASTM), 100 Barr
         Drive, West Conshohocken, PA 19428, (610) 832-9585 or FAX
         (610) 832-9555.

         1.   ASTM C 62-85A, "Standard Specification for Building
              Brick (Solid Masonry Units made from Clay or
              Shale)".

         2.   ASTM C 67-85, "Standard Methods of Sampling and
              Testing Brick and Structural Clay Tile".

    B.   Occupational Safety and Health Administration (OSHA).

         1.   "OSHA General Industry Safety and Health Standards
              (29 CFR 1910), Publication V2206.

         2.   "OSHA Construction Industry Standards (29 CFR
              1926).

         3.   Both regulations can be found in OSHA Publication
              2207, which includes a combination of both Parts
              1910 and 1926 as they relate to construction safety
              and health.  It is for sale by the Superintendent
              of Documents, U.S. Government Printing Office,
              Washington DC  20402.

1.03 SUBMITTALS

    A.   Product data:

         1.   Certified copies of mill reports indicating
              chemical and physical properties of threaded rebar.

         2.   Certificates of compliance for Portland cement, fly
              ash, lime and sand from an approved independent
              testing lab.

    B.   Quality Control Submittals:

         1.   Procedures: Submit descriptive data and written
              procedures for core drilling of holes and cutting
              out of access cavities in existing brick.

         2.   Submit schedule and description of procedure for
              drilling, inserting anchors and injection of grout.

         3.   Material Quality:  Submit reports of tests of the
              strengths of the threaded parts of reinforcing bar
              assemblies showing compliance with these
              procedures.  Certified material certificates may be
              provided in lieu of test reports when permitted by
              the Contracting Officer on the basis of adequate
              justification.


PART 2---PRODUCTS

2.01 MATERIALS

    A.   Steel Items:

         1.   Threaded reinforcing bars shall be deformed bar
              conforming to ASTM A615, Grade 60.

         2.   Threaded reinforcing bars shall have rolled or
              forged threads at one end capable of developing the
              following yield and tensile strengths:

              DIAMETER  SIZE YIELD          TENSILE
                             STRENGTH       STRENGTH

                3/4          #6   19,800 Pounds  33,000 Pounds
                7/8          #7   27,000 Pounds  46,000 Pounds
              1-1/8          #9   45,000 Pounds  76,000 Pounds

         3.   Nuts shall be hex head, heavy type conforming to
              ASTM A307 or as required by specifications of the
              manufacturer of the threaded reinforcing bars.
              Nuts shall be capable of developing in the bar the
              ultimate strength noted on the drawings.

    B.   Cementitious Materials:

         1.   Portland Cement:  ASTM C150, Type I or Type II low
              alkali.

         2.   Lime:  ASTM C207, Type S.

         3.   Fly Ash:  ASTM C618, Type F.

         4.   Silica Sand:  #30 and #90 Grit

         5.   Water:  Clean and potable (drinkable).

    C.   Grout Injection Equipment:

         1.   Mortar pump with agitation hopper that is capable
              of producing thirty p.s.i., with a pressure switch
              that will stop grout flow at thirty p.s.i.

         2.   Cement Mixer.

         3.   Volume measuring containers.

         4.   3/4 inch masonry drill bits and rotary drill motor.

         5.   Power Cord.

         6.   Water hose.

         7.   Water hose nozzle that is adjustable to 1/4 inch
              stream.

         8.   OSHA approved scaffold and/or ladders.

         9.   A 5/8 inch injection nozzle capable of penetrating
              to the core drilled hole containing the anchor.
              The nozzle shall have a device capable of retaining
              grout at a pressure of 27-30 p.s.i.  At 30 p.s.i.
              flow of grout to the tube must automatically be
              stopped.

         10.  Pressure monitoring system at ground level for use
              by the testing laboratory inspector.

         11.  Plastic foam joint filler for plugging injection
              ports to prevent grout flow:  preformed
              compressible, resilient, foam of diameter
              appropriate to prevent flow from injection ports.

2.02 MIXES

    A.   Grout Proportions and Mixing:

         1.   Parts shall be measured by volume.

         2.   Proportions:  

              3 parts #30 silica sand
              1 part #90 silica sand
              1 part Portland Cement
              1/2 part lime
              1/2 part fly ash

              Enough water to sufficiently achieve a consistency
              as determined by Section 2.02 A.3. below.

         3.   Consistency Test:

              a.   A grout sample shall be taken from the nozzle.
                   Fill a 2 inch diameter by 4 inch high
                   cylinder.

              b.   Pour the sample slowly from 12 inches high
                   onto an impervious smooth level surface.

              c.   Proper consistency is indicated by a six inch
                   to seven inch diameter puddle on the
                   impervious surface.  The diameter shall be
                   calculated as the average of 2 widths of the
                   puddle measured at right angles to each other,
                   one being the maximum width.

         4.   Grout mixing.  Thoroughly mix dry ingredients
              before adding water.  Mix in quantity that can be
              used in 1-1/2 hours after initially adding water to
              the dry ingredients.  Water may be added to
              maintain proper consistency during the allowed 1-
              1/2 hours.


PART 3---EXECUTION

3.01 PREPARATION

    A.   Surface Preparation:

         1.   Equipment:  Drilling equipment shall not be
              anchored into architectural finishes.  Finishes
              removed for access or clearance and damaged
              finishes shall be replaced to match the adjacent
              existing finishes.

         2.   Holes:

              a.   Cavities shall be formed by using non-impact
                   tools.

              b.   Holes for deep anchors shall be core drilled
                   to the depths required and locations.  Before
                   drilling, determine the location of
                   obstructions and the necessary clearances to
                   prevent damage to embedded pipes, windows, and
                   architectural finishes.

              c.   Roughen anchor holes by rotary wire brush
                   scouring full length.

              d.   Clean holes with high pressure air and a nylon
                   brush.

              e.   Drill injection ports with non-impact rotary
                   drill.

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   Drill holes for deep anchors.  The size of the holes
         shall be 3/8" minimum, 5/8" maximum larger than the
         nominal bar diameter.

    B.   Drill injection ports to intersect the deep anchor holes.
         Holes that miss the deep anchor holes shall be filled
         with injection grout.

    C.   Flush the hole and ports with water at full city pressure
         through a 1/4" nozzle.  Start flushing at the high point
         of sloping holes, working toward the low; at horizontal
         holes, start at the end, working toward the aperture;
         flushing each port in sequence until all ports have been
         flushed and water flows clean from the hole.  Use water
         adequate to saturate the brickwork.  Use vacuum to
         collect water as it emerges; to protect damage to
         finishes.

    D.   Insert bar anchors.  Secure bar anchors in proper
         position for connection to the hardware.

    E.   Inject grout starting at the low point.  Continue
         injection until grout flows from the next port.  Plug the
         port and continue injection and plugging of ports until
         flow stops at 30 p.s.i. pump pressure or the hole is
         filled.  If flow stops, immediately begin injecting at
         the next open injection port to be plugged and continue
         as above.  If the port will not take injection,
         immediately begin injection at the nearest open port and
         continue as above.

    F.   After hole is filled, remove plugs and fill injection
         ports with grout.

    G.   Wash grout spillage from wall immediately.  Remove and
         dispose of all spilled grout.

                         END OF SECTION