96E03/29/06

S638-96E.doc

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  When rock bolts are required, include 722.03 and the following:

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**Section 638. - ROCK BOLTS**

**Description**

**638.01** This work consists of furnishing and installing rock bolts.

**Material**

**638.02** Conform to the following Sections and Subsections:

> Grout 725.22 (a)
>
> Rock Bolts 722.03

**Construction Requirements**

**638.03 Submittal.** At least 14 days before the installation of rock
bolts, submit the following information:

**(a)** Evidence that the foreman has a minimum of 1500 hours and the
drill operator has a minimum of 1000 hours of satisfactory work in
similar installation of post-tensioned rock bolts.

**(b)** Construction sequence and schedule.

**(c)** Drilling methods and type of equipment.

**(d)** Proposed rock bolt, couplers, bearing plate, anchor unit, flat
washer, and beveled washer specifications including manufacture\'s data
sheets.

**(e)** If using resin adhesives, include manufacturer\'s data sheets
and placement procedures.

**(f)** Proposed grout mix design.

**(g)** Calibration data for each torque wrench to be used. Submit
results of calibration tests performed by an independent testing
laboratory within the last 60 days.

Allow 7 days for acceptance or rejection. Do not begin work until
submittals have been approved.

**638.04 Rock Bolt.** Size the bolt so the design load does not exceed
60 percent of the minimum guaranteed ultimate tensile strength of the
bolt. Select and fabricate bolts to carry the specified loads.

**638.05 Handling and Storage.** Protect bolts from dirt, mud, water,
and other harmful substances to avoid damage and corrosion. Do not use
rock bolts that are heavily corroded, pitted, damaged due to welding, or
show signs of abrasions, cuts, or nicks.

**638.06 Installation.** Drill holes at locations and depths shown in
the plans or directed by the CO. Drill rock bolt holes to the diameter
specified by the bolt manufacturer and to a depth that will allow 12
inches of open hole beyond the end of the specified rock bolt. Clean
holes of all drill cuttings, sludge, and debris before the rock bolt is
inserted or grout is injected into the hole. Drill holes for rock bolts
normal to the rock surface unless otherwise specified by the plans or
the CO.

Couple only grouted bolts. Couple sections together when standard,
commercially available lengths are exceeded. Provide a center stop for
connecting sections so that an equal length of thread connects each
section. Provide couplings that equal the manufacturers guaranteed
ultimate strength for the rock bolt. Do not fabricate couplings in a
manner that interferes with the flow of grout.

Insert bolt into the hole with the end of the bolt positioned
approximately 12 inches from the bottom of the hole. Attach the bearing
plate, washer, and nut to the bolt with the threaded outer end of the
bolt projecting beyond the nut at least 2 inches.

For grout-anchored bolts, inject sufficient grout into the drill hole to
fill the bond zone around the bolt. For mechanically anchored, hollow
stem rock bolts, inject grout through the hollow core of the bolt or
through a grout tube until the space between the bolt and drill hole
wall is filled and grout is forced out of the de-airing tube at the face
of the hole. Apply tension to bolt after the time specified in Table
638-1.

**Table 638-1**

**Grout Curing Time**

+------------------------------------+---------------------------------+
| **Cement Type**                    | **Curing Time**                 |
|                                    |                                 |
|                                    | **(Days)**                      |
+------------------------------------+---------------------------------+
| I                                  | 5                               |
+------------------------------------+---------------------------------+
| II                                 | 5                               |
+------------------------------------+---------------------------------+
| III                                | 3                               |
+------------------------------------+---------------------------------+

For bolts anchored with polyester resin, use fast setting polyester
resin cartridges in the bond zone and slow setting polyester resin
cartridges in the no load zone with gel times consistent with rapid
installation. Select cartridge diameters in accordance with the
manufacturer\'s recommendations to ensure complete encapsulation of the
rock bolt and satisfactory in-hole mixing. Break and mix resin
cartridges by spinning the bolt as it is inserted into the drill hole
according to the manufacturer\'s instructions.

**638.07 Tensioning.** Apply tension to the bolt with a calibrated
torque wrench to 100 percent of the design load.

Tension polyester resin anchored bolts immediately after the fast-set
resin in the distal bond zone has set up and before the slow-set resin
in the unbonded zone has set up.

Tension grouted bolts after the bonded length has been grouted and the
grout has set up but before the unbonded length is grouted.

Tension mechanically anchored rock bolts immediately after insertion
into the drill hole according to the manufacturer\'s recommendations and
the approved rock bolting plan. Upon tensioning, lock bolt off at the
specified lock-off load.

Allow the bolt to remain in place if:

-   The bolt can be tensioned to the design load.

-   The design load is maintained after final grouting has been
    accomplished.

Replace any bolt that does not meet (a) or (b) in a manner and in a
location approved by the CO.

**638.08 Acceptance.** Material for rock bolts will be evaluated under
Subsections 106.02 and 106.03.

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

**Measurement**

**638.09** Measure rock bolts by the foot or by the each.

**Payment**

**638.10** The accepted quantities, measured as provided above, will be
paid at the contract price per unit of measurement for the pay item
listed below that are shown in the bid schedule. Payment will be full
compensation for the work prescribed in this Section. See Subsection
109.05.

Payment will be made under:

**Pay Item Pay Unit**

63801 Rock bolt Foot

63802 Rock bolt Each