Amendment A001.pdf

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CO FTBR CRYSTAL DAM (1)

East Portal Access Road

Asphalt concrete 403, Type II

Construction Requirements

204.05 Conserved Topsoil. Delete the first sentence and substitute the following:

Conserve topsoil from the roadway excavation and from embankment foundation areas to the extent and depth determined by the CO.

204.07 Subexcavation. Delete the subsection and substitute the following:

204.07 Subexcavation.

Use separation-stabilization geotextile, class 2, type C, nonwoven.

Notify the CO of type and source of backfill material anticipated for subexcavation work at the preparatory phase meeting according to Subsection 153.04(a). Excavate unsuitable materials to the limits designated in the plans, or as directed by the CO. Notify the CO of any additional locations requiring subexcavation, or which require a change in surface dimension or depth.

Advise the CO of any adverse conditions such as active subsurface water or unstable soil conditions prior to backfilling. Dispose of unsuitable material according to Subsection 204.14.

Do not subexcavate during periods of inclement weather.

Submit a neat line drawing of the excavated volume for each subexcavation prior to backfilling.

Place geotextile according to Section 207 prior to placing soil or aggregate backfill materials in the subexcavation. Place and compact soil or aggregate backfill according to Section 204.11, or Section 403 for hot asphalt concrete backfill until the subgrade elevation is achieved. Prevent backfill materials from becoming contaminated with unsuitable materials. Replace the excavated structural section with the structural section shown in the typical section of the plans. Adjust the subgrade elevation to accommodate the replacement structural section.

204.14 Disposal of Unsuitable or Excess Material. Add the following:

Secure environmental clearances according to Subsection 107.10(d).

Bury excavated asphalt material between station 507+10 and 509+20 within the limits of environmental clearance with a minimum cover of 6 inches. Ensure the buried excavated asphalt material plus cover is flush with existing ground elevations.

Dispose excess excavated roadway and rock material down the existing talus slope located between stations 512+00 and 513+00 (Waste Site). Refer to Section 205.08 for processing requirements of excavated material. Reduce material to 24-inches in the maximum dimension prior to wasting. Do not waste asphalt material at Waste Site.

204.15. Add the following:

Geotextile will be evaluated under Section 207.

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East Portal Access Road vibration limitations when blasting in the vicinity of concrete, shotcrete or grout that has not developed full design strength (f’c).

(d) Blast Warning. The Contractor will establish a system of warning signals prior to blasting.

As a minimum, give warning signals at five minutes and one minute prior to each blast.

Additionally, give an all-clear signal after the shot has been examined for misfires or other problems. Warning signals must be audible throughout the work area and for a distance of at least 1,000 feet from the blast.

The Contractor will implement all necessary access restrictions to the area, including but not limited to pedestrians, vehicles, and bicyclists. The Contractor will coordinate with law enforcement officials and other agencies as necessary for closure of public roads and lands.

The Contractor will post signs warning the public that there is blasting being conducted in the area. Post warning signs in accordance with the Manual on Uniform Traffic Control Devices (MUTCD) and as necessary to assure public safety and to educate persons who may be in the area and at all roads, trails, paths, and clearly visible to anyone that may enter within 2,000 feet of the work area

(e) Drilling. Stake all laybacks, contour grading, and other design modifications from the nominal slopes.

Remove all overburden soil and loose or decomposed rock along the top of the excavation for a distance of at least 30 feet beyond the end of the production hole drilling limits, or to the end of the cut, before drilling blast holes. Do not remove such materials by blasting. Pioneer the tops of cuts as stipulated under Subsection 204.04. Do not perform clearing further than 15 feet beyond the staked cut limits unless approved by the CO. Conserve all topsoil as stipulated under Subsection 204.05.

Pioneering the tops of cuts and preparing a working platform to begin the controlled blasting drilling operations may require difficult access working methods and use of specialized equipment. For rock cut areas inaccessible to standard track drill equipment the contractor should anticipate the need to utilize unusual difficult access methods such as hand drilling, specialized drill equipment, or horizontal drill holes. At the Contractor’s discretion, difficult access drilling methods not listed in the SCR may be submitted to the CO for approval. Use hole diameters established for controlled blasting when pioneering. Do not space holes greater than 6 feet when pioneering. Use close hole spacing and light charges to prevent fly rock escaping beyond the construction limits.

After pioneering and rock slope scaling operations, remove all material deposited on the roadway. Crush the excavated material to no larger than 1-foot by 1-foot by 1-foot in volume prior to disposing at the Waste Site as defined in Section 04.14.

Following approval of the blasting plan, drilling for blast holes may commence. Log the holes and record drilling production. Maintain a logged record of holes drilled and keep the log available for inspection by the CO at any time, and provide a copy upon request. When variations in the rock formation are indicated by the drill holes that are significant enough to call into

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East Portal Access Road question the suitability of the blast pattern, stop the drilling and revise and resubmit the blasting plan to the CO for review. After approval of the revised plan, commence drilling according to the revised plan.

The Contractor will at a minimum, provide surveyed points on 20 foot stations through curves and 50 foot stations in tangent sections indicating grade and centerline offset on the backslope after each lift has been excavated and before drilling begins for the next lift. Perform this work under the supervision Surveyor. Surveying will not be paid for separately, but will be included in the cost of the work.

Affix mechanical devices permanently or temporarily to all drilling equipment used to drill controlled blast holes, to determine accurately the angle at which the drill steel enters the rock.

Do not drill controlled blast holes if these devices are either missing or inoperative. Drill controlled blastholes within 4 inches of the staked collar location. The CO may require redrilling of holes drilled outside the 4 inch tolerance. Stake and locate drill holes in accordance with the approved blasting plan.

Do not exceed 20 feet for the bench height and length of drill holes for individual lifts, unless approved by the CO. If the Contractor successfully demonstrates to the CO that drill hole alignment can be controlled within approved tolerances and produce the desired cut face, then the CO may allow 30 foot tall (maximum) bench heights and individual drill holes.

When the cut height will require more than one lift, a maximum 18 inch offset between lifts is permitted to allow for drill equipment clearance. Begin controlled blasthole drilling at a point which will allow for necessary offsets and adjust, at the start of lower lifts, to compensate for drift which may have occurred in the upper lifts. Construct the working benches so the final ditch alignment and grade conform to the typical section shown on the plans. Obliterate remaining shelves resulting from the drilling offset.

Limit subdrilling of controlled blast holes for cushion or smooth blasting to one half of the hole spacing or 24 inches (600 mm), whichever is deeper.

205.09 Scaling.

Inspect rock surfaces and scale loose rock and blast debris immediately after each blast.

Remove or stabilize all rock on the cut face that is loose, hanging, or that creates a potentially dangerous situation to the satisfaction of the CO. Accomplish the work by using experienced and suitably equipped individuals or heavy equipment. Perform scaling according to Section

623. Scaling on the final cut face is subsidiary to 204 excavation.

After each blast, the Contractor will scale rock on the final cut face that appears loose, overhanging, or that could create a potentially hazardous situation during construction.

Scalable rock on the final cut face will be removed or stabilized to the satisfaction of the CO during or upon completion of the excavation in each lift. Leave minor irregularities or surface variations in place if they do not create a hazard. Crush the excavated material to no larger than 1-foot by 1-foot by 1-foot in volume prior to disposing at the Waste Site as defined in Section 04.14. Drilling of the next lift cannot proceed until this work has been completed. Subject to

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