Installing Steel Bar Anchors in Brick Walls with Cementitious Grout

PART 1–GENERAL

1.01 SUMMARY

1. 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 thefollowing:

   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.

2. 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

1. American Society for Testing Materials (ASTM)

   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”.

2. 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

1. 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.

2. 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

1. 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.

2. 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).

3. 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

1. 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:

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

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

      3. 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

1. 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:

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

      2. Holes for deep anchors shall be core drilled to the depths required and locations. Before drilling, determine the location of

      3. obstructions and the necessary clearances to prevent damage to embedded pipes, windows, and architectural finishes.

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

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

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

3.02 ERECTION, INSTALLATION, APPLICATION

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

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

3. 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.

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

5. 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.

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

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