Precast Concrete Fiber Optic and Utility Vault SECTION 13 431 PRECAST CONCRETE FIBER OPTIC AND UTILITY VAULT
Part 1 — General
1.1 Section Includes
A.Precast concrete fiber optic and utility vaults , and maintenance markers.
B.Type I V-CV, and Type V-CV Precast Concrete Fiber Optic and Utility Vaults.
1.2 Related Sections
A.Section 02056: Embankment, Borrow, and Backfill
B.Section 02221: Remove Structure and Obstruction
C.Section 03575: Flowable Fill
D.Section 13553: ITS Conduit
E.Section 16530: Electrical Power
1.3 References
A.AASHTO LRFD Bridge Design Specifications
B.USDA Rural Utilities Service (RUS)
1.4 DEFINITIONS Not Used
1.5 Submittals
A.Manufacturer’s shop drawings .
1.Shop drawings must bear the seal of a Licensed Professional Engineer and will not deviate from the functional dimensions shown.
B.Manufacturer’s product specifications for information
C.Manufacturer’s w arranty provisions Precast Concrete Fiber Optic and Utility Vault
Part 2 — Products
2.1 Fill
A.Free Draining Granular Backfill – Refer to Section 02056 .
B.Granular Backfill Borrow – Refer to Section 02056.
C.Flowable Fill – Refer to Section 03575.
D.Hand- mix grout
1.Minimum strength – 50 psi
2.Maximum strength – 150 psi
3.Slump – 5 inches to 10 inches
2.2 Fiber Optic Vaults and Covers
A.Fiber vaults – pre-cast concrete. Refer to AT Series Standard Drawings for dimensions of vault types.
B.Provide fiber vaults that are adjustable upwards to meet a new finished grade by the addition of manufacturer -provided risers, collars, or grade rings.
C.Provide fiber vaults that have the cover frames cast separately from the vault structure and are removable and replaceable.
D.Furnish an internal heavy -duty non- metallic cable storage rack system on two opposite fiber vault walls.
1.Furnish and install two stanchions on each rack wall.
a.Fasten to the fiber vault wall according to the manufacturer’s instructions.
b.Stanchions are a minimum of 36 inches for Type IV -CV fiber vault racks.
c.Stanchions are a minimum of 45 inches For Type V -CV fiber vault racks.
2.Use cable rack arms that are appropriate for the amount of slack cable being installed but not be less than 4 rack arms in a Type IV vault and 5 rack arms in a Type V vault, capable of supporting a minimum of 250 lb.
E.Suppl y Type IV -CV Fiber Optic and Utility Vault s with a hinged metal lid for unpaved areas or a heavy duty round manhole -style lid in paved areas.
1.Supply Type V -CV vault s with a manhole- style lid only. Precast Concrete Fiber Optic and Utility Vault
2.Fiber vault s with hinged metal lids will be rated for AASHTO LRFD HL – 93 loading according to AASHTO LRFD Bridge Design Specifications .
3.Fiber vaults with round manhole style lids will be rated for AASHTO LRFD HL- 93 loading according to AASHTO LRFD Bridge Design Specifications .
F.Provide hinged metal lids that have double- doors (split) and double hinges .
1.Provide a lid that operates freely over 180 degrees.
2.Provide a lid with drop handles for easy opening.
3.Provide a neoprene gasket between the hinged lid and the vault frame.
G.Provide lids with a grounding lug with ½ - 13 NC female threads on the underside of the manhole and hinged metal lid s.
H.Provide hinged and manhole lids with Penta -Head vandal resistant stainless steel bolts with washer .
1.All bolt holes must be self-draining.
I.Furnish hinged metal lids that have a non- skid diamond pattern or similar surface that has a raised pattern of at least 3/32 inch high.
J.Provide l ids for all vaults that are marked, “UDOT FIBER OPTIC” using a minimum 3 inch high letters with 1/8 inch line thickness.
1.Form the letters by engraving, casting, stamping, or with a precise weld bead.
K.Manhole Lid Ac cess Points – recessed steel pull slots or holes to allow removal or opening of the manhole with a hook or lever.
2.3 Maintenance Markers
A.Furnish and install Utility Marker P osts for each vault location. Refer to AT Series Standard Drawings.
2.4 Ground Rod
A.Ground Rod - Refer to Section 16530.
2.5 Wiring
A.Grounding Conductor – Refer to Section 16530 . Precast Concrete Fiber Optic and Utility Vault
2.6 Locate Ball Or Disk
A.Place a locate ball or disk in each vault .
1.Color – orange
2.Requires no particular orientation when buried
3.Place in bottom of each box
4.Designed to last as long as the supplied vault
5.Produces a uniform, spherical RF field in all directions
6.Signal peak when directly over the ball
7.Meets RUS Specifications
Part 3 — Execution
3.1 Backfill
A.Place 12 inches of F ree Draining Granular Backfill under vaults .
B.Hand tamp G ranular Backfill Borrow or approved native soil around the vault lid on unpaved surfaces .
1.Match the top 6 inches to the composition, density, and elevation of the surrounding surface.
3.2 Fiber Optic and Utility Vault
A.Install according to manufacturer’s recommendations and AT Series Standard Drawings
B.Core drill holes to match conduit entry where required without damaging the vault . Core drill holes at thin wall sections only. Do not “knock out” thin wall sections. Use grout to create a complete seal between conduit and the structure wall. Finish grout smooth and flush with the interior wall.
1.Make core drilled holes in vault not more than ¼ inches larger than conduit diameter.
2.Seal conduit and micro -duct ends inside all vaults with at least 2 inch thick duct seal after cables are installed.
3.Seal vacant conduit and micro- ducts with a manufactured conduit plug and attach detectable pull tape. Refer to Section 13553.
C.Install vault plum and level and grade backfill flush with vault.
D.Do not locate fiber vaults on slopes or low lying locations with poor drainage.
E.Do not install vaults within the traveled way or shoulders unless shown . Precast Concrete Fiber Optic and Utility Vault
F.Conduit in fiber vaults
1.Install conduit s into thin wall section only .
2.Extend PVC conduit 2 inches, HDPE conduit 6 inches, micro- duct oversheath 6 inches and individual micro- ducts 2 ft beyond the inside wall of the vault.
3.Align ITS conduit ends by color at each side of the box.
4.Install bushings on all conduits before cable installation according to Section 13553 .
5.Refer to AT Series Standard Drawings.
G.Remove concrete sidewalk or other surfaces .
1.Refer to Section 02221.
2.Replace with in -kind materials to match the existing grade, texture, and color of concrete or other surface.
H.Encase conduit in flowable fill or hand- mix grout where the conduit enters the fiber optic vault.
3.3 Restoration
A.Restore areas disturbed or damaged during the installation of all vaults .
Source: Utah Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 1211–1215 of 1,331.