SECTION NONPRESTRESSED ROCK ANCHORS. 1. Placing drawings. 2. Bar details. 3. Manufacturer s data, and recommendations for grout.

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1 SECTION NONPRESTRESSED ROCK ANCHORS PART 1 GENERAL 1.1 THE REQUIREMENT A. The Work in this Section consists of all construction operations relating to designing, furnishing, and installing, complete nonprestressed rock anchors. 1.2 SUBMITTALS A. Shop Drawings: 1. Placing drawings. 2. Bar details. 3. Manufacturer s data, and recommendations for grout. B. Information Submittals: 1. Grout test results. 2. Volumes of grout take for each grouting of each anchor hole. 3. Pullout test results. 4. Calibration data for pullout test load measurement system. 5. Record drawings showing final location, elevation, and depth of each anchor bar hole. 1.3 SCHEDULING AND SEQUENCING A. Install and complete pullout tests for rock anchors for spillway construction prior to installing relief wells below the spillway slab in accordance with Section 02502, UNDERDRAIN SYSTEM. PART 2 PRODUCTS 2.1 ROCK ANCHORS FOR PORTAL CONSTRUCTION A. Rock anchors for portal construction at the outlet conduit shall be continuous upset threaded bars, such as manufactured by Dywidag or equal with manufacturer supplied nuts and washers. The rock anchors shall be of single length without splicing. Rock anchors shall have a steel plate nominally 6 inches by 6 inches NONPRESTRESSED ROCK ANCHORS

2 2.2 ROCK ANCHORS FOR SPILLWAY CONSTRUCTION A. Rock anchors for installation below the spillway slab shall be continuous deformed steel bar conforming to the requirements for Grade 60 steel as specified by ASTM A615. Furnish full length bars with applicable bends. B. Welding or splicing of steel bar will not be allowed. 2.3 ANCHOR GROUT A. Nonshrink cementitious grout for rock anchors shall be a pumpable, nonmetallic, nonshrink grout containing no chlorides, such as Masterflow 928 grout manufactured by Master Builders, Inc. of Cleveland, OH, or equal. The 28 day strength for the grout shall not be less than 7,000 psi. 2.4 CONSOLIDATION GROUT A. Composition: 1. Portland Cement: ASTM C150, Type II. 2. Sand: ASTM C33, fine aggregate, except 100 percent shall pass No. 8 sieve. 3. Water: Clean and free of deleterious substances. B. Compressive Strength: Minimum 3,500 psi at 14 days. C. Water-Cement Ratio: Range from 0.40 to 0.45 by weight. D. Water Loss: Control bleeding by adding sand. PART 3 EXECUTION 3.1 GENERAL A. All rock anchors for portal construction shall be installed in accordance with the recommendations of the rock reinforcement manufacturer. 3.2 DRILLING A. Anchor Locations, Elevations, Depths, and Orientation: 1. As shown, unless adjusted by CONSTRUCTION MANAGER subject to conditions encountered in field. 2. Final locations, elevations, and depths shall be as follows: a. Rock Anchors for Portal Construction: Within plus or minus 1 foot NONPRESTRESSED ROCK ANCHORS

3 b. Rock Anchors for Spillway Construction: Within plus or minus 0.3 feet. 3. Final orientations shall be within plus or minus 5 degrees. B. Method: 1. Coring, rotary drilling, or percussion-air-hammer type drilling. 2. Use water or air with sufficient moisture for dust control to remove cuttings. 3. Do not use rod dope, grease, or other lubricants in drilling operations. C. Minimum Hole Diameter: Largest of following. 1. Hole diameter as shown /2 times bar diameter. 3. As required to accommodate grout and vent tubes with bar centered in hole. 3.3 HOLE PREPARATION FORANCHOR INSTALLATION AND GROUTING A. If water or caving conditions are encountered, fill hole with consolidation grout and drill out grout after it sets. Repeat grouting and redrilling until dry and stable hole is achieved. B. After completion of dry and stable hole, wash sides of hole with nozzle that impinges water on sides of hole with sufficient velocity to remove loose or caked material from the hole. C. Immediately prior to anchor installation, reflush hole with water if necessary to saturate surfaces, sound hole for compliance with required depth, and remove standing water from hole. D. Prevent entry of unwanted grout, concrete, or debris into drilled holes until anchor installation and grouting is completed. 3.4 HOLE ABANDONMENT A. If hole is rejected by CONSTRUCTION MANAGER, fill hole with grout as specified for anchor grouting. B. Drill new hole in location determined by CONSTRUCTION MANAGER. 3.5 BAR PREPARATION A. Immediately prior to installation, remove dirt, grease, loose rust, or other deleterious substances from bar and check passages through hollow bars, if used, with air or water to ensure that they are clear NONPRESTRESSED ROCK ANCHORS

4 3.6 VENT AND GROUT TUBE PREPARATION A. Immediately prior to insertion, check vent and grout tubes with air or water to ensure that they are clear. 3.7 BAR INSTALLATION A. Install each bar prior to grouting. B. Rigidly support each bar centered in its hole during placement of grout and until grout sets. C. Alternatively, install bar after completely filling hole with grout, provided bar can be pushed into position without damage, and grout cannot flow out of hole by gravity. 3.8 VENT AND GROUT TUBE INSTALLATION A. For anchors installed in holes drilled horizontally or downward, insert grout tube with its discharge end at back or bottom of hole, respectively. B. Grout Tube Diameter: 1 inch, minimum. C. Vent Tube Diameter: 1/4 inch, minimum. 3.9 PLACING GROUT A. Equipment used and installation, proportioning and mixing of grout and grouting the rock reinforcement shall be in accordance with the equipment and procedures recommended by the manufacturer of the rock anchor, unless otherwise modified or permitted by the CONSTRUCTION MANAGER. B. Grouting equipment shall be capable of continuous mechanical mixing that will produce uniform and thoroughly mixed grout. Grouting equipment shall be capable of a high enough pressure to clear any obstructions in the tube, and shall prevent introduction of oil, air, or other foreign substance into the grout. C. Nonshrink grout shall be injected at a consistency with a 20 to 30 second flow period with the Corps of Engineers Flow Cone Method CRD-C611. The grout shall be pumped into the hole continuously until the flow from the hole is the same consistency as the grout being injected. D. Grout shall be injected such that all air or water can be vented from the hole during the injection process NONPRESTRESSED ROCK ANCHORS

5 3.10 TESTING GROUT A. Compressive Strength: 3.11 PULLOUT TESTS 1. Determine compressive strength of grout cubes sampled and tested in accordance with CRD-C Minimum of one test per day and whenever proportion of mix is changed. A. Frequency: 1. Rock Anchors for Portal Construction: Test a minimum of five anchors to verify adequate pullout resistance. 2. Rock Anchors for Spillway Construction: Test a minimum of 5 percent of anchors to verity adequate pullout resistance. B. CONSTRUCTION MANAGER will determine which anchors shall be tested. C. Test anchors after grout has achieved 4,000 psi compressive strength. D. Apply test load in tension equal to 80 percent of yield strength of bar. Maintain load for minimum of 10 minutes. If total bar movement between 1 minute and 10 minutes exceeds 0.08 inches (2 mm), or if application of full test load is not possible, anchor will be rejected. E. Test Apparatus: Conform to ASTM D4435 for each of following items. 1. Loading system. 2. Load transducer. 3. Displacement transducer. 4. Displacement transducer support. F. Load measurement systems shall be calibrated by independent testing laboratory and accurate to within plus or minus 5 percent of actual load. G. Method of load application shall not damage bar. H. Install replacement anchors for each failed anchor at location determined by CONSTRUCTION MANAGER. I. Retest one additional anchor bar for each failed bar in addition to number initially required. END OF SECTION NONPRESTRESSED ROCK ANCHORS