GM_17-16.pdf

There were two aesthetic preferences that the Park preferred for the slope scaling and rock reinforcement work, and one that included preservation of the pavement from scaled rocks.

These design modifications are discussed in this following section.

MODIFICATIONS TO INITIAL GEOTECHNICAL RECOMMENDATIONS

The design and construction modifications preferred by the Park are detailed under each bullet below. They are as follows:

• The Park requested that vine maples above the south portal, and when possible above the north portal, be preserved. Language has been added to Section 623 – Special Labor (Slope Scaling) special contract requirement (SCR) to allow the contracting officer (CO) to direct the vegetation removal work. One tree has also been identified as a hazard tree and will be removed at the direction of the CO. A suggested SCR for Section 623 – Special Labor (Slope Scaling) is attached to this memorandum for development of the final contract plans and specifications.

• The Park requested that we preserve the existing pavement as much as possible during the rock slope scaling and rock reinforcement work, so we recommend using a jersey barrier at centerline filled with up to 18 inches of loose soil or sand between centerline and the inside ditch. This loose pad of soil or sand will dissipate the energy of the falling rocks and reduce the likelihood for potential impacts to the existing pavement surface. Figure 1 provides a typical cross-section of the proposed temporary roadway protection we recommend for the north and south portal slopes.

Please note that 24 hours a day traffic control will be needed as long as this temporary rockfall protection measure is in-place. A suggested SCR for Section 651 – Rockfall Protection is attached to this memorandum for development of the final contract plans and specifications.

• The Park requested that we remove the rock bolt and dowel heads from the rock reinforcement and cover them with an integrally colored and/or textured grout that matches the natural rock outcrop. This technique has been utilized in other Parks and has worked well to blend in with the surrounding landscape and also reinforce unstable blocks of rock. Figure 2 shows a recent project in Crater Lake National Park that required rock bolt and dowel head removal with integral grout used to match the rock outcrop. A suggested set of SCR’s for Section 260 – Rock Bolts and Dowels and Section 722 – Anchor Material are attached to this memorandum for development of the final contract plans and specifications. The SCR includes language that allows for the Park to review the integral colors selected for the grout.

• There is an error in the March 5, 2014 geotechnical memorandum on Page 5 that should be corrected in the contract plans and specifications for this project. On page 5 we estimated approximately 60 lineal feet of rock dowels when it should have been 110 lineal feet of rock dowels.

CLOSING

If you should have any questions or concerns with the information presented in this geotechnical memorandum, please contact Doug Anderson at 360-619-7958 or Nathan Jenks at 360-619-7748.

Figures

TYPICAL SECTION

PROTECTION

TEMPORARY ROADWAY

Existing

C.1

STATE PROJECT

NUMBER

SHEET

WA NPS MORA 123(1)

A

M

A p r il

U

S S u r ft

D c m y fi le s p w p r o d u c ti o n d m o r a c a .d g n

R J o h n s o n

C O

U G

A R T

E A

M

C h e c k e d b y

D e s ig n e d b y

NO SCALE

Rock slope

LC

Unclassified borrow

Total paved width varies, 22' typicalVaries

Varies Varies 11'-0" Min.

barrier, temporary

Precast concrete

WITH UNCLASSIFIED BORROW

TEMPORARY ROADWAY PROTECTION

FIGURE 1

NPS Drwg. No. _______

NPS PMIS No. 216994

Figure 2. A photograph of a rock bolt and dowel installation with their head’s cut off utilizing integral grout to blend the installations with the surrounding landscape. The rock reinforcement locations are within the red circles.

Special Contract Revisions

Delete Section 260 and substitute the following:

Section 260. — ROCK BOLTS

Description

260.01 This work consists of furnishing and installing rock bolts and dowels.

Rock bolts are post tensioned, fully grouted deformed steel bars that actively reinforce a rock mass.

Rock dowels are untensioned, fully grouted deformed steel bars that passively reinforce the rock mass.

Before starting the work in this Section, scale the slope area identified in the plans in accordance with Section 623.

Materials

260.02 Materials. Provide rock bolts, anchor devices, bearing plates, couplers, and other equipment produced by a manufacturer regularly engaged in the manufacturing of materials for the construction of rock bolts and dowels conforming to the following Section and Subsections:

Nonshrink grout 725.13(b) Rock bolts and rock dowels 722.03 Water 725.01(a)

Construction Requirements

260.03 Qualifications. Provide an on-site Drill Foreman and Drill Operator(s) with experience installing and testing rock bolts and dowels. Submit the following for approval at least 21 days before starting work:

(a) Provide a resume for the drill foreman and operator(s) that demonstrate their drilling experience for the rock bolting and doweling requirements under this contract.

Documentation of safe and satisfactory drill work experience will be verified by the CO through prior project work history. The drill foreman and operator(s) need to provide project owner information that includes name, title, and current contact information for each job submitted.

(b) The drill foreman must have installed a minimum of 3000 linear feet of rock bolts and dowels on a minimum of 5 projects over the past 5 years, and the drill operator(s) must have installed a minimum of 1000 linear feet of rock bolts and dowels on a minimum of 3 projects over the past 5 years.

(c) The contractor must have at least 2 years of experience installing rock bolts and dowels.

The CO may request a list of projects to verify the contractor’s experience.

260.04 Submittals. At least 21 days before starting rock bolt and dowel installation, submit the following according to Subsection 104.03. Do not proceed with any related work until the CO has approved these documents in writing.

(a) Proposed construction sequence and schedule;

(b) Proposed drilling methods and equipment;

(c) Proposed method to access the rock bolt and dowel locations with the drill equipment;

(d) Proposed drill hole diameter and the minimum bond zone length. The minimum bond zone length must be designed in accordance with the guidance provided in the Post Tensioning Institute (PTI) publication entitled, Recommendations for Prestressed Rock and Soil Anchors;

(e) Proposed rock bolt and dowel type, couplers, bearing plate, washers (flat and beveled), nut, stressing anchorages, centralizers, and bond breakers (if applicable) with specifications including manufacture’s data sheets, catalog cuts and mill certificates. Include manufacturer’s verification for the bearing plate thickness for the specified rock bolt and dowel capacities;

(f) Manufacturer recommendations for bar and hardware handling, storing, and working temperature ranges;

(g) Grout type, mix design, placement procedures including manufacturer’s data sheets and catalog cuts;

(1) Cement grout. Mixing equipment and 3-day grout compressive strength test results.

(a) Two-stage nonshrink cement grouting. Means for determining the level of primary (first-stage) grout in the hole; and

(b) Single-stage nonshrink cement grouting. Fabrication details for proposed bond-breaker in the free stressing zone including corrosion inhibiting compounds, when applicable.

(h) Manufacturer certification and statement of manufacturer’s compliance for corrosion-resistant bar coating along with procedures and material for repairing corrosion protection on bars in the field;

(i) Methods, equipment, and materials used to control excessive grout injection volumes when open joints, seams, or loose material is encountered;

(j) Details for placing, stressing, and testing rock bolts and dowels. Schedule a test installation to demonstrate rock bolt or dowel installation, testing equipment, and procedures.

Include the proposed rock bolt stressing equipment, setup, and procedures that will be used for the performance and proof testing;

(k) Detailed procedure for placing the anchor head assembly (bearing plate and nut) below the exposed rock surface or for removing the anchor head assembly following final lock-off without impacting the bar design load. Include details for a countersink or flush-cut with a colored grout patch, when applicable;

(l) Special installation methods (such as upwardly inclined rock bolts and dowels, techniques for constructing bearing pads, grouting across open joints and debris-filled discontinuities that will be used to ensure a fully-grouted, well-protected installation) when applicable;

(m) Identification number and calibration test certification for each jack, pressure gauge, and electronic load cell to be used for testing. Clearly indicate the serial number of each component of the testing assembly on calibration graphs. Submit results from calibration tests conducted by an independent testing laboratory within the previous 60 days; and

(n) Report documentation examples including installation and testing report formats.

260.05 Safety. Work site safety is the responsibility of the Contractor. Perform all work in a manner to minimize exposure to the public, construction personnel, and equipment to hazardous and potentially hazardous conditions. Utilization of temporary rock blocks, special designs, or installation procedures that the Contractor deems necessary to safely install rock bolts and dowels are the responsibility of the Contractor and will be implemented at the discretion of the Contractor and incidental to the unit contract price for rock bolts and rock dowels.

260.06 Rock Bolt and Dowel Fabrication.

(a) General. Fabricate rock bolts and dowels according to PTI, Recommendations for Prestressed Rock and Soil Anchors. Rock bolt and dowel steel tendons must not be precut at the factory to lengths shown in the plans, but will be delivered to the job site in bulk lengths and field cut to the appropriate lengths following drilling for each rock bolt and dowel. Size tendons to ensure:

(1) The design load does not exceed 60 percent of minimum ultimate tensile strength of the bar; and

(2) The maximum test load does not exceed 80 percent of the minimum ultimate tensile strength of the bar.

(b) Couplers. Couple only fully-grouted anchors. Couple sections together only when the design length exceeds the standard commercially available bar lengths. Use couplers with a center stop to ensure equal length of thread connects each section. Do not use couplings that interfere with the flow of grout.

(c) Anchorage. For the stressing anchorage, use a steel bearing plate, washers (flat hardened, beveled or spherical, as required), and a nut capable of developing 95 percent of the minimum ultimate tensile strength of the tendon.

(d) Centralizers. For cement grouted rock bolts and dowels, place centralizers along the tendon at 10-foot (2.5-meter) centers, with at least one centralizer per rock bolt or dowel.

Locate the lowermost centralizer within 12 inches (300 millimeters) of the end. Use centralizers of sufficient strength to support the tendon bar in the drilled hole and provide a minimum of 0.5 inches (13 millimeters) of grout cover around it. Do not place centralizers on the bond breaker if one is used.

260.07 Handling and Storing Material. Handle and store tendons according to ASTM D3963, the manufacturer’s recommendations, and Subsection 256.06. If significant damage has occurred to any corrosion protection coatings on the bars, the CO may reject them at no cost to the Government.

260.08 Installation. Furnish and install rock bolts and dowels with a minimum design capacity of 25,000 pounds (25 kips). Select and construct rock bolts to carry the specified loads and supply all access, materials, equipment, and labor necessary to install the rock bolts and dowels.

(a) Drilling. Provide equipment capable of drilling straight and uniform-diameter holes. Do not use water or drilling slurry. Drill rock bolt and dowel hole collars and hole depths within 6 inches (150 millimeters) of the required location and at least to the minimum depths shown in the Plans. Total bolt and dowel lengths will vary based on encountered subsurface conditions and may be adjusted by the CO. Drill the rock bolts and dowels perpendicular to the rock face or inclined slightly downward (0 to 5 degrees) from the axis of the bolt and the rock face, if not otherwise specified in the Plans, or as directed by the CO. Size the drill hole diameters to provide at least 0.5 inches (13 millimeters) of grout cover around the tendon.

Clean drill holes of cuttings, sludge, and debris. Re-drill holes in which bolt or dowel installation is not possible at no additional cost to the Government. Use of hand drills for advancing the hole will not be allowed without the written approval of the CO and demonstrated effectiveness by the Contractor.

(b) Grouting. Install the rock bolt or dowel within 24 hours of completing the drill hole.

Orient reinforcement within 5 degrees of the specified angle. Complete first stage grouting within one week of rock bolt and dowel installation. Tension each rock bolt and dowel within one week of completing the first stage grouting. Complete second stage grouting for rock bolts within three days of successful post tensioning.

(1) Cement grout installations. Use a positive displacement grout pump according to Subsection 256.07(b)(1).

Install the bar and batch and inject grout according to the manufacturer’s recommendations. Two stage grouting is required for all rock bolts. The first stage grouting is to fill the rock bolt bond length and the entire length of the rock dowels with grout. The second stage grouting is only used for the rock bolts to fill the free-stressing (unbonded) length of the installation after successful post tensioning. Control grout pressures to avoid ground heaving or fracturing. Fill the grout tube with grout if it will remain in the hole.

Flush all surplus water and diluted grout from all lines prior to injection. Replace any fitting that leaks before continuing with the grouting operation. Clean any excess grout off the rock surface from around the rock bolt and dowel and bearing plate following grout operations. All testing related to the minimum compressive strength of the grout is the responsibility of the contractor and will be incidental. The CO may also request samples for testing.

Record the quantity of injected grout and the grout pressure for each installation. Notify the CO of grout quantity overruns including the reason for the overrun and proposed actions to minimize future overruns. Obtain approval for alternative grouting methods.

(c) Bearing plate installation. Place the bearing plate so at least three quarters of the plate’s surface is in contact with a rock face. Chip out surrounding rock or construct a bearing pad approved by the CO if the rock face is irregular or unsound, or the axis of the rock bolt or dowel is within 20 degrees of being perpendicular to the bearing plate and the tendon passes through the center of the bearing plate without bending the bolt or dowel. Use beveled washers if the axis of the tendon is greater than 5 degrees from perpendicular to the bearing plate. Allow at least 4 inches (100 millimeters) of bolt length beyond the nut and washers.

The CO may also require the use of over-sized bearing plates, when the rock surface is weak or highly weathered.

After load-testing and acceptance, tension and lock-off the rock bolts, place the second stage of nonshrink cement grout in the entire free stressing length. Remove excess grout from the rock face and anchor assembly.

For rock bolt and dowel installations, ensure the tendon is fully encapsulated in grout to the collar of the hole. Check the grout level the next day through the key-hole and top off with additional grout using a tremie tube to fill the annulus space. Any time additional grouting is needed, recheck the level the following day and repeat as necessary until a fully grouted annulus space is achieved.

For all rock bolts and dowels, remove the bearing plates and protruding end of the rock bolts and dowels in accordance with Subsection 260.12 after the final stage of grout has reached a final set per the manufacturer’s recommendations, or a minimum compressive strength of 60% of the 7-day compressive strength.

260.09 Rock Bolt Testing, Stressing, and Finishing. Conduct testing of tensioned rock bolts and untensioned rock dowels according to PTI, Recommendations for Prestressed Rock and Soil Anchors.

If applicable, trim the corrosion protection surrounding the free stressing length of the tendon so it does not contact the bearing plate during testing and stressing. For single stage cement grouted rock bolts, tension the tendon after the bond zone grout is set and reaches sufficient pull-out strength. For two stage cement grouted rock bolts, tension the tendon after the bond zone grout is set and reaches sufficient pull-out strength and before the free stressing length is grouted. For mechanical anchored rock bolts, tension the tendon immediately following insertion in the hole and before fully grouting.

(a) Performance testing. Do not start production bolting until the Contractor has completed successful performance tests of their rock bolt design, and it is accepted by the CO. At the CO’s discretion, the Contractor must conduct up to two performance tests in each rock type to demonstrate the effectiveness of the construction method for each rock bolt design, and when a significant change is proposed in the construction method. The performance test can be done on a production bolt specified in the plans or in a sacrificial location if reasonable access is not provided by the Contractor per Subsection 106.01 and FAR Clause 52.246-12 for inspection.

Tension rock bolts to 120 percent of the design load with a calibrated hollow-ram hydraulic jack and gauge with graduations no larger than 200 psi for a holding time of not more than 60 minutes. During the hold period, do not allow the load to deviate from the test pressure by more than 200 psi. Re-pump as necessary to compensate for small movements and changes. Take load and extension measurements during tensioning with a measuring device such as a dial gauge or vernier scale capable of measuring to 0.001 inches (0.025 millimeters). Provide all testing equipment, monitor the test, and document the results in accordance with the requirements specified in this Section. The CO will analyze the rock bolt test results and determine whether the rock bolt is acceptable. A rock bolt is acceptable if both of the following conditions are satisfied:

(1) The total elastic movement obtained at the maximum test load exceeds 80 percent of the theoretical elastic elongation of the free stressing length and

(2) The rock bolt will carry the maximum test load with a creep rate that does not exceed

0.04 inches between 1 minute and 10 minutes, or 0.08 inches per log cycle of time between the 6 minute and 60 minute readings.

If the Contractor fails to successfully achieve these testing criteria, the CO may require additional performance tests to be completed at no additional cost to the Government.

(b) Proof testing. Proof test each production rock bolt to 120 percent of the design load and hold for 10 minutes. If no loss of load occurs in this time period, the rock bolt is accepted. If a rock bolt fails this proof test, document the expected reasons for failure and address and rectify any deficiencies in the rock bolt installation methods to the satisfaction of the CO before installing any additional rock bolts. The failed rock bolt must be replaced with an additional rock bolt installed in a separate hole, typically within the same rock block at no additional cost to the Government.

After tensioning and achieving a successful rock bolt proof test, lower the tension and lock off the load at 100 percent of the design load with a nut and either a flat or beveled washer as needed to ensure that the nut is flush against the bearing plate. Grout the remaining portion of the rock bolt within 72 hours after re-tensioning and lock off. Trim the end of the completed rock bolt to within 4 inches of the rock face.

260.10 Rock Dowel Lift-Off Testing and Finishing. Conduct testing of rock dowels according to PTI, Recommendations for Prestressed Rock and Soil Anchors.

Test only fully grouted dowels. Conduct at least five successful lift-off tests in succession for each different rock type, anchor type, and proposed drilling-installation-grouting method.

Gradually load lift-off test reinforcements to 60 percent of the minimum ultimate tensile strength of the dowel tendon and monitor the pressure gage to verify the anchor is holding the design load for at least 10 minutes. If the anchors do not pull out, test 5 percent of the remaining dowels. If pressure is lost on the pressure gage due to anchorage movement, replace the dowel and conduct lift-off tests on an additional five anchors in succession until all are satisfactory.

260.11 Drilling Logs, Test Results, and Reporting. Submit drilling logs and test results to the CO for review. Maintain daily records of rock bolt and dowel work in a manner acceptable to the CO, including:

(a) As-built drawings depicting the location of each anchor, noting anchor designation, date drilled, general drilling logs that note the drilling conditions and materials encountered, the location of any significant drilling changes (e.g. geologic contacts, voids, or open fractures), dates of all grouting operations, total anchor length, bonded length, free stressing length, grout mix, grout volume, average grout pressure, hole diameter, size of tendon, tendon inclination, and installation comments. Submit as-built drawings according to Section 104 after work completion.

(b) Performance and proof test data forms, including the anchor designation, bonded length, free stressing length, stressing length, date of stressing operation, signature of stressing operator or inspector, required elongation and associated gage pressure, actual elongation and associated gage pressure, identification numbers of jacking equipment, comments, and a table including incremental jack pressure, jack load, and movement.

260.12 Special Rock Bolt and Dowel Requirements. For all rock bolt locations, two stage grouting is required and a bond breaker is not permitted. Once the 2nd stage of grout has set for the two-stage cement-grouted rock bolts and the 1st stage cement grouted rock dowels, remove the nut, all washers, the keyhole bearing plate; and cut the protruding end of the rock bolt and dowel flush with the rock surface. Cover the cut-off rock bolt and dowel and the grout-filled annular space with cement colored grout (integrally or topically) and textured to match the surrounding native rock as approved by the CO. Immediately remove/clean any excess grout off the rock surface.

Prior to starting grout work provide color methods meeting manufacturer’s recommendations.

Submit color charts representing available color selections for the grout material in a range of dark, earth-tone colors representative of rock features found in the local landscape for approval by the CO. Allow 7 days for approval.

260.13 Acceptance. See Table 260-1 for sampling, testing, and acceptance requirements.

Material for rock bolts and dowels will be evaluated under Subsections 106.02, 106.03, and

106.04. Construction of rock bolts and dowels will be evaluated under Subsections 106.02 and

106.04. Grouting will be evaluated under Subsections 106.02 and 106.04. Installed rock bolts and dowels will be evaluated under Subsections 106.02 and 106.04.

Measurement

260.14 Measure the Section 260 items listed in the bid schedule according to subsection 109.02 and the following as applicable. Measure rock bolts and dowels by the linear foot of rock bolt and dowel installed, fully tensioned, grouted, tested and accepted by the CO. The rock bolts and dowels will be measured to the face of the slope.

Payment

260.15 The accepted quantities will be paid at the contract price per unit of measurement for the Section 260 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05.

DIVISION 250

Table 260-1 Sampling, Testing, and Acceptance Requirements

Material or Product

(Subsection)

Type of Acceptance (Subsection)

Characteristic Test Methods Specifications

Sampling Frequency

Point of Sampling Split Sample Reporting Time

Source

Aggregate Quality (fine)

(703.01)

Measured and tested for conformance (106.04 & 105)

Quality AASHTO M 6 1 per material type

Source of material Yes Before producing

Mix Design

Non-shrink Grout

(725.13(b))

Measured and tested for conformance (106.04)

Flow ASTM C939 1 per mix design Source of material

Yes, when requested Before producing

Compressive Strength (3-day and 7-day)

ASTM C942

1 set from 2 separate batches of grout

Source of material

Yes, when requested Before producing

Production

Performance test for rock bolts

Measured and tested for conformance (106.04)

Deformation Subsection 260.09(a)

Subsection 260.09(a) Installation No

Within 24 hours after completion of test

Proof test for rock bolts

Measured and tested for conformance (106.04)

Deformation Subsection 260.09(b) Each bolt Installation No

Within 24 hours after completion of test

Lift-off test for rock dowel

Measured and tested for conformance (106.04)

Deformation Subsection 260.10

Subsection

260.10 Installation No

Within 24 hours after completion of test

Section 623. — GENERAL LABOR

Description

623.01 Delete this Subsection and substitute the following:

This work consists of scaling (removing) loose or detached blocks of rock from cut slopes and natural rock outcrops. This work also consists of cutting trees and removing vegetation from the face of rock slopes.

Construction Requirements

623.02A Rock Slope Scaling General. (Added Subsection).

Conduct general scaling within the rock slope scaling boundaries as shown on the plans, or as otherwise directed by the CO, from the inside roadway ditch line to within 10 vertical feet above the cut slope brow. Specific unstable blocks and/or areas requiring more intensive scaling effort are identified in the plans as intensive scaling areas. Cut trees and vegetation only at the locations shown in the plans, or as directed by the CO. Perform the rock slope scaling before any other slope stabilization work or permanent rockfall mitigation measures are implemented.

Provide temporary roadway protection to safeguard the public and existing facilities from rockfall and debris related to rock scaling operations in accordance with Section 651. The rock scaling work includes cleanup and hauling of scaled material and existing accumulated ditch debris in accordance with Section 105.

623.02B Rock Slope Scaling Equipment. (Added Subsection).

Perform scaling using rope or cable supported laborers with scaling bars. Portable hydraulic wedges, air pillows, hand drills, splitters, or other mechanical means and/or hand tools may be used by the contractor if approved in writing by the CO. Continued use will be permitted if the techniques are demonstrated to be effective in performing the work and result in acceptable appearance, as determined by the CO. Mechanical scaling using excavators, cranes, and other heavy equipment is not permitted. Minor scaling and material removal using an excavator at locations low on the slope and adjacent to the roadway ditch line may be permitted at the discretion of the CO.

623.02C Rock Slope Scaling Submittals. (Added Subsection).

Experience Requirements. At least 21 calendar days before starting rock slope scaling work, submit the following information, in writing, to the CO for review:

Provide workers, including Scaling Foreman and Qualified Scalers that are experienced and qualified to perform the work. Apprentice Scalers will only be allowed to work on slopes less than 50 vertical feet in total height, and they will need to meet the minimum training certifications to be considered.

(a) Provide written evidence that the rock slope Scaling Foreman and Qualified Scalers have performed satisfactory work in similar capacities elsewhere for a sufficient length of time to be qualified to perform their duties.

(b) The Scaling Foreman is required to have a minimum of 1,500 hours and no less than 3 years of documented experience as a rock slope scaling foreman. Each Qualified Scaler is required to have a minimum of 1000 hours and at least 1 year of documented experience on similar projects.

(c) If Apprentice Scalers are proposed, provide written evidence that the Apprentice Scaler has completed Society of Professional Rope Access Technicians (SPRAT) Level I training and certification in addition to a minimum of 500 hours of dual rope access in the last year (http://www.sprat.org). SPRAT Level II certified candidates and veterans meeting Veterans Preference (minimum 50 percent) with a DD Form 2134 or equivalent DD Form documenting an Honorable Discharge of the Veteran will be given priority.

Rock Slope Scaling Work Plan Submittal.

At least 21 calendar days before starting rock slope scaling work, submit a detailed plan for the rock slope scaling detailing the following information, in writing, to the CO for review:

(a) The proposed construction sequence and schedule;

(b) The types of equipment and tools to be utilized in the work;

(c) The number of rock slope Scaling Foremen, Qualified Scalers, and Apprentice Scalers that will be on the project. Identify a minimum of two Qualified Scalers for each Apprentice Scaler;

(d) Removal and disposal plan for existing ditch debris and rock and debris generated from the rock slope scaling work; and

(e) Traffic control plan including provisions to protect the roadway, traffic, facilities, and existing utilities.

Work cannot proceed until the CO has approved these documents in writing.

623.02D Rock Slope Scaling Operations. (Added Subsection).

(a) Work site safety is the responsibility of the Contractor. Perform all work in a manner to minimize exposure to the public, construction personnel, and equipment to hazardous and potentially hazardous conditions. Public traffic is not allowed in the work zone during active rock slope scaling operations. Perform rock slope scaling only when the Scaling Foreman is present to direct work. No time will be tracked, or paid under Special Labor-Slope Scaling, for the rock slope scaling work if the Scaling Foreman is not present. Two-way radio contact must be maintained at all times between the Scaling Foreman, on-slope scalers, traffic control, and any equipment operators.

(b) The Scaling Foreman must have visual contact with all scalers on the slope at all times or additional Scaling Foremen will be required to observe all scalers at all times on the slope.

The Scaling Foreman may not be actively scaling on the slope with the on-slope Scalers.

(c) If any Apprentice Scalers are approved for the work, Apprentice Scalers must be assigned to a minimum of two Qualified Scalers while on the slope, and under the direct supervision of the Scaling Foreman. The two Qualified Scalers must be designated, in writing to the CO, and work closely with the Apprentice Scaler during all on-slope activities. If, at any time, a Qualified Scaler designated to an Apprentice Scaler is not available, a qualified replacement will need to be submitted to the CO and approved before on-slope work can begin. If there is no replacement Qualified Scaler submitted, or available, the Apprentice Scaler will not be allowed to perform any on-slope work. Apprentice Scalers are only permitted to work on slopes less than 50 feet in vertical height. If an apprentice scaler is performing in a dangerous or unsafe manner at any time, they will be removed from the project by the CO.

(d) Prior to starting the rock slope scaling or vegetation removal, the Temporary Roadway Protection Plan (TRPP) must be approved in writing by the CO and installed as outlined in the approved TRPP and Section 651.

(e) Cut the identified trees and other vegetation as shown in the plans, or as otherwise directed by the CO. Cut trees and large woody shrubs as close as possible to the ground surface while leaving the root wad intact. Vegetation removal must occur before the rock scaling operations begin.

(f) Establish anchors for cable or ropes within 100 feet of the top of existing cut slopes unless otherwise approved by the CO.

(g) In general, start slope scaling at the top of the designated slope scaling limits and proceed downward toward the road, removing loose, detached, or identified blocks/areas of rock as the work progresses.

(h) All safety scaling beyond the rock slope scaling boundaries and outside the vegetation removal identified in the plans without explicit direction from the CO, will not be tracked, or paid under Special Labor-Slope Scaling, and is incidental to the work outlined in this Section.

(i) Conduct general and intensive rock slope scaling operations in accordance with the details shown in the plans, the traffic control restrictions and requirements shown in the plans and specified in Special Contract Requirements, and in the rock slope scaling work plan as approved by the CO.

(j) Remove any scaled rock blocks that hang up on the slope during the scaling operations.

The scaled area will be reviewed by the CO to determine if the rock slope scaling has been completed. If additional rock blocks are identified for removal, continue to scale the slope until the scaling has been completed to the satisfaction of the CO.

(k) Replace the Scaling Foreman if they must leave for any reason with a qualified replacement.

(l) Break up any rocks that are too large to transport into manageable sized pieces for haul using mechanical methods or as approved by the CO.

(m) Do not leave accumulated scaling debris on the roadway, in the roadside ditch, or in any pull-off adjacent to the roadway outside the barriered rockfall containment section overnight.

(n) Re-grade all ditches and benches to a smooth surface with the original (functional) drainage condition, and remove existing ditch debris and accumulated rockfall debris from the scaling operations to the designated disposal area in Section 105.

Measurement

623.04 Delete this Subsection and substitute the following:

Measure the Section 623 items listed in the bid schedule according to Subsection 109.02 and the following as applicable.

Special Labor, Slope Scaling will be measured by the scaler hour. Measurement will begin from the time a Qualified Scaler is equipped and begins to climb the slope until the Qualified Scaler has descended the slope.

Special Labor, Slope Scaling Apprentice will be measured by the scaler hour. Measurement will begin from the time an Apprentice Scaler (with a minimum of two Qualified Scalers) is equipped and begins to climb the slope until the Apprentice Scaler (with a minimum of two Qualified Scalers) has descended the slope.

The Scaling Foreman is incidental to the work, and no additional measurement will be made for the Scaling Foreman.

Cleanup and removal of existing roadway ditch material and scaled material to the designated disposal area(s) is also incidental to the work.

Round portions of an hour to the nearest half hour at the end of each shift. Measure time in excess of 40 hours per week at the same rate as the first 40 hours.

Section 651. — ROCKFALL PROTECTION

(ADDED SECTION)

Description

651.01 This work consists of installing temporary roadway protection. Temporary roadway protection consists of temporary roadway protection with borrow, a precast concrete barrier at centerline, and a contractor selected method to protect the rock masonry façade of the tunnel portals.

Material

651.02 Conform to the following:

Precast concrete barriers 725.09(b) Unclassified borrow 704.06

Submittals

651.03 Submittals. Submit a Temporary Roadway Protection Plan (TRPP) to the CO for approval at least 21 calendar days before the start of rockfall mitigation work as described below.

Do not initiate temporary roadway protection measures until the submitted plan has been approved by the CO in writing. Include the following:

(a) Describe how the temporary roadway and tunnel portal masonry protection will be constructed, monitored, and maintained during the slope scaling portion of the project, and removed following the on-slope work;

(b) Describe the protection method that will be used to protect the tunnel portal rock masonry, and the equipment that will be used to remove accumulated scaling debris.

(c) List the equipment that will be used to place the blanket of unclassified borrow on the roadway and remove accumulated rockfall debris. Describe how the blanket of unclassified borrow will be placed and how the accumulated rockfall debris will be removed from behind the precast concrete barriers near centerline; and

(d) List the procedures that will be followed to allow emergency vehicles through the site at all times.

Construction Requirements

651.04 General. Safety of the work is the responsibility of the Contractor. Perform the work in a manner to minimize hazards and exposure to the public, construction personnel, and equipment. For temporary traffic control see Subsection 156.04.

Install and maintain the temporary roadway protection measures to extend a minimum of 25 feet beyond the active scaling area on the roadway. Include a precast concrete barrier terminal section taper at the end of each precast concrete barrier section. Do not perform slope scaling without the appropriate type of temporary roadway measures and tunnel portal measures in place. Dispose of all temporary roadway protection unclassified borrow outside the Park, unless otherwise approved by the CO.

Existing masonry is present at both tunnel portal locations. Protect the masonry from damage during slope scaling and other construction activities. Any additional damage to the existing masonry due to scaling and other construction activities will be repaired at the Contractor’s expense.

Place an 18 inch thick blanket of unclassified borrow between the base of the rock slope and the precast concrete barrier near the roadway centerline, as shown in the plans. The required unclassified borrow specifications are listed in Subsection 704.06.

Remove accumulated rockfall debris from behind the precast concrete barrier near centerline and behind the tunnel portal masonry protection when the debris has filled the catchment area, or when scaled rock begins to pass over the barrier protection. For the roadway protection, at the discretion of the CO, accumulated debris from scaling may be bermed against the inside (slope side) of the precast barrier near centerline to help retain scaled material to the catchment area if scaled rock is completely arrested and captured.

At the discretion of the CO, patch any damaged roadway surface areas resulting from slope scaling or other construction activities completed under this contract according to Section 403 at no additional cost to the Government.

At the discretion of the CO; repair any damaged permanent pavement markings resulting from placement of the roadway protection outlined in this section or any other construction activities completed under this contract according to Section 634 at no additional cost to the Government.

At the discretion of the CO, re-establish existing contours.

651.05 Acceptance. Material and construction of the temporary roadway protection will be evaluated under Subsection 106.02.

Measurement

651.06 Measure the Section 651 items listed in the bid schedule according to Subsection 109.02.

Temporary roadway protection will be by the lump sum.

Payment

651.07 The accepted quantities will be paid at the contract price per unit of measurement for the Section 651 pay items listed in the bid schedule. Payment will be full compensation for the work described in this Section. See Subsection 109.05.

Section 722. — ANCHOR MATERIAL

722.03 Rock Bolts. Delete the title and text of this Subsection and substitute the following:

722.03 Rock Bolts and Rock Dowels.

Bars. For rock bolts provide continuously threaded steel reinforcement bars conforming to either; AASHTO M 31 Grade 60 or 75 deformed bar, ASTM A 615 Grade 60 or 75 deformed bar, ASTM A 706 Grade 60 or 80 deformed bar, ASTM A 722 Grade 150 Type II, or AASHTO M 275 Grade 150 Type II capable of being post-tensioned to the design loads, performance test loads, and proof loads specified. The bending requirements of AASHTO M 31, ASTM 615, and ASTM 706 will be waived. Provide rock bolts with a threaded end length of at least 6 inches at each end of the bolt to accommodate appropriate accessories. The rock bolt rod may be coupled as long as the coupling does not interfere in any way with the placement of grout and the coupling is interconnected by a threaded tubular connection of sufficient strength, and thread engagement with the bolt rod sections, to transfer the full design load of the rock bolt.

For rock dowels provide continuously threaded steel reinforcement bars with a minimum bar size of No. 7 and conforming to either; AASHTO M 31 Grade 60 or 75 deformed bar, ASTM A 615 Grade 60 or 75 deformed bar, or ASTM A 706 Grade 60 or 80 deformed bar. The bending requirements of AASHTO M 31, ASTM 615, and ASTM 706 will be waived.

Corrosion Protection. Provide anchor bar steel for rock bolts and dowels with epoxy coating in accordance with either AASHTO M 284, ASTM A 775, or ASTM A 934. The patching material, compatible with the coating material and inert to the grout selected for use, must be supplied with each shipment.

Appurtenances. Bearing plate size will be reviewed and approved by the CO in accordance with Section 6.10 of Post Tensioning Institute “Recommendations for Prestressed Rock and Soil Anchors” Fourth Edition – 2004. Bearing plate thickness shall not be less than ¾ inch and its dimensions not less than 8 inches by 8 inches, or as shown on the plans.

Nuts and couplers must exceed 100 percent of the MUTS (Minimum Ultimate Tensile Strength) of the bar. For Grade 60, 75, and 80 bar, the nuts and coupler must conform to either AASHTO M 169 or ASTM A 108. For Grade 150 bar the nuts must conform to either ASTM A 29 or ASTM A 536, couplers must conform to ASTM A 29.

Washers must conform to ASTM F 436. Spherical and beveled washers must conform to ASTM A 536 or ASTM A 47.

Provide centralizers fabricated from plastic or material which is non-detrimental to the pre-stressing steel. Wood centralizers are not permitted.

Grout. Conform to Subsection 725.13(b) for grout used with rock bolts and dowels. No epoxy or polyester resin bonding agents will be allowed.