Rev. 1-6-97

PRECAST REINFORCED CONCRETE 3-SIDED CULVERT

714-R-282

 

DESCRIPTION. This work shall consist of constructing a precast reinforced concrete arch culvert, or a precast reinforced concrete flat topped culvert in accordance with sections 105.03 and 714.

BASIS OF ACCEPTANCE. Acceptability of the 3-sided culvert will be determined based on the results of the concrete compressive strength tests, the material requirements described herein, and the inspection of the finished product. The culvert manufacturer shall submit shop drawings and design computations signed by and bearing the seal of a registered professional engineer for review and approval. Culvert manufacture shall not begin until written approval of the shop drawings and design computations has been received from the Engineer.

PRECAST REINFORCED CONCRETE ARCH CULVERT

Where precast reinforced concrete arch culvert is shown on the plans, the culvert has been sized for the precast reinforced concrete arch culvert.

The Contractor shall have the option to use a precast reinforced concrete flat topped culvert. Such culvert shall be redesigned. The computations and drawings for the redesign shall be signed and sealed by a professional engineer. The redesigned structure shall provide the hydraulic opening shown on the plans.

(a) MATERIALS.

1. CONCRETE. Concrete shall be air-entrained when installed in areas subject to freeze-thaw conditions. The concrete shall be composed of portland cement, fine and coarse aggregates, admixtures and water. Concrete shall contain 6.5 " 1.5 percent air. The air entraining admixture shall be in accordance with ASTM C 260.

a. CEMENT. Portland cement shall be in accordance with the requirements of ASTM C 150 Type I, Type II, or Type III cement.

b. FINE AGGREGATE. Fine aggregate shall be natural sand in accordance with 904.01.

c. COARSE AGGREGATE. Coarse aggregate shall consist of stone having a maximum size of 25 mm (1 in.). Aggregate shall be in accordance with 904.02.

d. WATER-REDUCING ADMIXTURE. The manufacturer may submit a water-reducing admixture for approval. Such admixture may be used for the purpose of increasing workability and reducing the water requirement for the concrete.

e. CALCIUM CHLORIDE. The addition of calcium chloride or admixtures containing calcium chloride will not be permitted.

2. STEEL REINFORCEMENT AND HARDWARE. All reinforcing steel shall be fabricated and placed as shown on the shop drawings.

Reinforcement shall consist of welded wire fabric in accordance with ASTM A 185 or ASTM A 497, or deformed billet steel bars in accordance with ASTM A 615M Grade 420 (ASTM A 615 Grade 60). Longitudinal distribution reinforcement may consist of welded wire fabric or deformed billet-steel bars. Both mats of top slab reinforcing and exterior wall mat reinforcing shall be epoxy coated.

(b) DESIGN. The culvert dimension and reinforcement details shall be as shown on the plans and the shop drawings, subject to the permissible variations shown herein. The minimum concrete compressive strength shall be 27.6 MPa (4,000 psi). The minimum yield strength of the steel shall be 415 MPa (60,000 psi).

The culvert sections shall be designed for HS20-44 loading in accordance with the AASHTO Standard Specifications for Highway Bridges. A minimum of 0.3 m (1 ft) of cover above the crown of the culvert will be required in the installed condition.

1. PLACEMENT OF REINFORCEMENT. The concrete cover over the outside circumferential reinforcement shall be a minimum of 50 mm (2 in.). The concrete cover over the inside circumferential reinforcement shall be a minimum of 38 mm (12 in.). The clear distance of the end circumferential wires shall not be less than 25 mm (1 in.) nor more than 50 mm (2 in.) from the ends of the culvert. Reinforcement shall be assembled utilizing single or multiple layers of welded wire fabric, or utilizing a single layer of deformed billet-steel bars. The welded wire fabric shall be composed of circumferential and longitudinal wires in accordance with the spacing requirements shown herein. The fabric shall contain sufficient longitudinal wires extending through the culvert to maintain the shape and position of reinforcement. Longitudinal distribution reinforcement may be welded wire fabric or deformed billet-steel bars in accordance with the spacing requirements shown herein. The ends of the longitudinal distribution reinforcement shall be not more than 75 mm (3 in.) from the ends of the culvert.

2. BENDING OF REINFORCEMENT. The outside and inside circumferential reinforcing steel for the corners of the culvert shall be bent to an angle which is approximately equal to the configuration of the culvert's outside corner.

3. LAPS, WELDS, AND SPACING. Tension splices in the circumferential reinforcement shall be made by means of lapping. Laps may be tack welded together for assembly purposes. For smooth welded wire fabric, the overlap shall be in accordance with ACI 12.9 and ACI 12.20. For deformed welded wire fabric, the overlap shall be in accordance with ACI 12.8 and ACI 12.19. For deformed billet-steel bars, the overlap shall be in accordance with ACI 12.2. For splices other than tension splices, the overlap shall be a minimum of 300 mm (12 in.) for welded wire fabric or deformed billet-steel bars. The center to center spacing of the circumferential wires in a wire fabric sheet shall be not less than 50 mm (2 in.) nor more than 100 mm (4 in.). For the wire fabric, the center to center spacing of the longitudinal wires shall not be more than 200 mm (8 in.). The center to center spacing of the longitudinal distribution steel for either line of reinforcing in the top slab shall be not more than 400 mm (16 in.).

(c) MANUFACTURE.

1. MIXTURE. The aggregates, cement, and water shall be proportioned and mixed in a batch mixer to produce a homogeneous concrete with compressive strength in accordance with the requirements herein. The proportion of portland cement in the mixture shall not be less than 390 kg/m; (658 lb/cu yd) of concrete.

2. CURING. Culvert sections shall be cured for a length of time so that the concrete develops the specified compressive strength in 28 days or less. One of the following curing methods or a combination thereof shall be used.

a. STEAM CURING. The culvert sections may be low pressure, steam cured by means of a system that shall maintain a moist atmosphere.

b. WATER CURING. The culvert sections may be water cured by means of a method which shall keep the sections moist.

c. MEMBRANE CURING. A sealing membrane in accordance with ASTM C 309 may be applied. Such membrane shall be left intact until the required concrete compressive strength is attained. The concrete temperature at the time of application of the compounds shall be within 6 NC (10 NF) of the atmospheric temperature. The concrete shall be damp when the compound is applied.

3. FORMS. The forms shall be rigid and accurate so as to maintain the culvert dimensions within the permissible variations shown herein. All casting surfaces shall be of smooth material.

4. HANDLING. Handling devices or holes shall be stored so as to prevent cracking or damage. The units shall not be stored in an upright position until the compressive strength is a minimum of 27.6 MPa (4,000 psi).

(d) PERMISSIBLE VARIATIONS.

1. INTERNAL DIMENSIONS. The internal dimensions shall not vary more than one percent from the design dimensions nor more than 38 mm (12 in.), whichever is less. The haunch dimensions shall not vary more than 19 mm (3/4 in.) from the design dimensions.

2. SLAB AND WALL THICKNESS. The slab and wall thicknesses shall not be less than those shown in the design by more than 6 mm (3 in.). A thickness of more than that required in the design shall not be cause for rejection.

3. LENGTH OF OPPOSITE SURFACES. Variations in laying lengths of 2 opposite surfaces of the culvert shall not be more than 16 mm (5/8 in.) in each culvert section, except where beveled ends for laying of curves are specified.

4. LENGTH OF SECTION. The underrun in the length of a section shall not be more than 13 mm (2 in.).

5. POSITION OF REINFORCEMENT. The maximum variation in position of the reinforcement shall be " 13 mm (2 in.). The cover over the reinforcement shall not be less than 38 mm (12 in.) for the outside circumferential steel or shall not be less than 25 mm (1 in.) for the inside circumferential steel as measured to the external or internal surface of the culvert. These tolerances or cover requirements will not apply to the mating surfacing of the joints.

6. AREA OF REINFORCEMENT. The areas of steel reinforcement shall be the design steel areas as shown on the shop drawings. Steel areas of greater than those required shall not be cause for rejection. The permissible variation in diameter of reinforcement shall be in accordance with the tolerances shown in the ASTM specification for that type of reinforcement.

(e) MARKING. Each culvert section shall be clearly marked with waterproof paint. The following information shall be shown on the inside of the vertical leg of each culvert section.

1. Culvert span and rise

2. Date of manufacture

3. Name or trademark of the manufacturer

(f) TESTING.

1. TYPE OF TEST SPECIMEN. Concrete compressive strength shall be determined from compression tests made on cylinders or cores. For cylinder testing, a minimum of 4 cylinders shall be taken during each production run. For core testing, one core shall be cut from a culvert section selected at random from each group of 15 culvert sections or less of a particular size and production run. For each continuous production run, each group of 15 culvert sections of a single size or fraction thereof shall be considered separately for the purpose of testing and acceptance. A production run shall be considered continuous if not interrupted for more than 3 consecutive days.

2. COMPRESSION TESTING. Cylinders shall be made and tested in accordance with ASTM C 39. Cores shall be obtained and tested for compressive strength in accordance with ASTM C 497.

3. ACCEPTABILITY OF CYLINDER TESTS. Failure of one of the 28 day test cylinders to be in accordance with the 90 percent of minimum compressive strength requirement may be cause for rejection.

4. ACCEPTABILITY OF CORE TESTS. The compressive strength of the concrete in each group of culvert sections as defined above will be acceptable when the core test strength is equal to or greater than the design concrete strength.

If the compressive strength of the core tested is less than the design concrete strength, the culvert from which that core was taken may be recored. If the compressive strength of the recore is equal to or greater than the design concrete strength, the compressive strength of the concrete in that group of culvert sections will acceptable.

If the compressive strength of a recore is less than the design concrete strength, the culvert from which that core was taken will be rejected. Two culverts from the remainder of the group shall be selected at random. One core shall be taken from each. If the compressive strength of both cores is equal to or greater than the design concrete strength, the compressive strength of the remainder of that group of culvert sections will be acceptable. If the compressive strength of either of the 2 cores tested is less than the design concrete strength, the remainder of the group of culvert sections will be rejected. However, at the option of the manufacturer, each culvert section of the remainder of the group shall be cored and accepted individually. The culvert sections which have cores with less than the design concrete strength will be rejected.

5. PLUGGING CORE HOLES. The core holes shall be plugged and sealed by the manufacturer so that the culvert section shall be in accordance with all test requirements shown herein. Culvert sections so sealed will be considered satisfactory for use.

6. TEST EQUIPMENT. The culvert maufacturer shall furnish all facilities and personnel necessary to carry out the tests required.

(g) INSPECTION. The quality of materials, the process of manufacture, and the finished culvert sections shall be subject to inspection by the Engineer.

(h) REJECTION. Culvert sections shall be subject to rejection if they are not in accordance with the specification requirements. A culvert section may be rejected due to the following conditions.

1. Fractures or cracks pass through the wall, except for a single end crack which does not exceed one half the thickness of the wall

2. Defects which indicate proportioning, mixing, or molding which are not in accordance with this specification

3. Honeycombed or open texture

4. Damaged section ends, where such damage prevents making a satisfactory joint

 

(i) REPAIRS. Culvert sections may be repaired, if necessary, due to imperfections in manufacture, handling damage, or construction. Repairs will be acceptable if it is determined that the repairs are sound, properly finished and cured, and if the repaired culvert section is in accordance with the requirements herein.

(j) CONSTRUCTION REQUIREMENTS.

1. FOOTINGS. The culvert sections shall be installed on cast-in-place concrete footings. The design, size, and elevation of the footings shall be as determined by the Engineer. A step up of 75 mm (3 in.) shall be formed in the top surface of the footing. Such step up shall be 50 mm (2 in.) clear of the inside face of the culvert. The footings shall be given a smooth float finish. The footing concrete shall reach a compressive strength of 14 kPa (2,000 psi) before placement of the culvert sections. The completed footing surface shall be constructed in accordance with the grades shown on the plans. When tested with 3 m (10 ft) straightedge, the surface shall not vary more than 6 mm in 3 m (3 in. in 10 ft).

2. PLACEMENT OF CULVERT SECTIONS. The culvert sections shall be placed as shown on the plans. The culvert sections shall be set to the true line and grade. The culvert sections shall be set on 130 mm x 130 mm (5 in. x 5 in.) masonite or steel shims. A minimum gap of 13 mm (2 in.) shall be provided between the footing and the bottom of each culvert section's vertical legs. The gap shall be filled with cement grout. Such grout shall consist of cement and water or cement mortar composed of one part portland cement and 3 parts sand, by volume, and water.

3. JOINTS. The culvert sections shall be produced with flat butt ends. The ends of the culvert section shall be such that when the sections are laid together they shall make a continuous line of culvert with a smooth interior free of irregularities, all compatible with the permissible variations shown herein. The joint width shall not exceed 19 mm (3/4 in.).

4. EXTERNAL PROTECTION OF JOINTS. The butt joint made by 2 adjoining culvert sections and between the culvert and precast wingwalls shall be covered with a joint wrap of minimum width of 300 mm (9 in.). The surface shall be free of dirt before the joint material may be applied. The external wrap shall be in accordance with ASTM C 877. The joint shall be covered continuously from the bottom of one culvert section leg, across the top of the arch, and to the opposite culvert section leg.

The joint wrap shall be kept in its proper location over the joint during the backfilling operation.

5. WORKMANSHIP AND FINISH. The culvert sections shall be free of fractures. The ends of the culvert sections shall be normal to the walls and centerline, within the limits of the permissible variations shown herein, except where beveled ends are specified. The surface of the culvert section shall be a smooth steel form or troweled surface. Trapped air pockets causing surface defects shall be considered as part of a smooth steel form finish.

6. BACKFILLING. Backfill shall be considered as all replaced excavation and new embankment adjacent to the culvert and wingwalls. Excavation for structures and roadway excavation, and embankment construction shall be in accordance with 206 except as modified herein.

Backfill material within 1.2 m (4 ft) of each side of the culvert shall be B borrow for structure backfill in accordance with 211. Maximum dry density shall be determined by AASHTO T 99 or another approved method. Backfill shall be placed and compacted in layers until the granular material is compacted to not less than 95 percent of the maximum dry density. No backfill shall be placed against structural elements until they have been approved.

Backfill against a waterproofed surface shall be placed so as to avoid damage to the waterproofing material.

Mechanical tampers or approved compacting equipment shall be used to compact all backfill and embankment immediately adjacent to each side of the culvert, and over the top of the culvert until it is covered to a minimum depth of one foot (0.3 m). The backfill within 1.2 m (4 ft) of each side of the culvert shall be placed in loose depth lifts of 150 mm (6 ft) or less. Heavy compaction equipment shall not be operated in the backfilled area or over the culvert until it is covered to a depth of 0.3 m (1 ft).

Lightweight bulldozers or graders may be operated over a culvert having 0.3 m (1 ft) of compacted cover. If earth moving equipment is used which weighs in excess of 11 Mg (12 t) and has a track pressure of 55 kPa (8 psi) or greater, the culvert will require 0.6 m (2 ft) of cover.

The backfill shall be placed and compacted to the same elevation on both sides of the culvert and wingwalls before proceeding to the next layer.

Backfill in front of wingwalls shall be carried to the ground lines shown on the plans.

PRECAST REINFORCED CONCRETE FLAT TOPPED CULVERT

Where precast reinforced concrete flat topped culvert is shown on the plans, the culvert has been sized for the precast reinforced concrete flat topped culvert.

The Contractor shall have the option to use a precast reinforced concrete arch culvert. Such culvert shall be redesigned. The redesigned structure shall provide the hydraulic opening shown on the plans. The computations and shop drawings shall be signed and sealed by a professional engineer.

(a) MATERIALS.

1. CEMENT. Portland cement shall be in accordance with 901.

2. AGGREGATES. Fine aggregate shall be natural sand in accordance with 904.01. Coarse aggregate shall have a standard size designation from No. 5 through No. 8, as specified in 904.02. The quality requirements of 904.02 will apply.

3. ADMIXTURES. Air entraining admixtures and chemical admixtures in accordance with 912.03 may be used.

4. STEEL REINFORCEMENT. Reinforcement shall consist of welded wire fabric in accordance with 910.01(b)4 or 910.01(b)5, or deformed billet steel bars in accordance with ASTM A 615M Grade 420 (ASTM A 615 Grade 60). Both mats of top slab reinforcing and exterior wall mat reinforcing shall be epoxy coated.

(b) DESIGN. The culvert design shall be in accordance with the AASHTO Standard Specifications for Highway Bridges. Design loading shall be HS20-44 loading. The culvert dimensions shall be as shown on the plans, subject to the permissible variations shown herein. The minimum concrete compressive strength shall be 34.5 kPa (5,000 psi).

1. MODIFIED DESIGNS. The manufacturer may request approval of modified designs which differ from the approved design.

2. PLACEMENT OF REINFORCEMENT. The concrete cover dimension over reinforcement shall be a minimum of 25 mm (1 in.). If the earth cover over the culvert deck is less than 0.9 m (3 ft) measured at the edge of the roadway pavement, the minimum concrete cover dimension over the top line of reinforcement in the deck shall be 50 mm (2 in.). The clear distance of the end circumferential wires shall not be less than 15 mm (5/8 in.) nor more than 50 mm (2 in.) from the ends of the culvert section. Reinforcement shall be assembled using a combination of a maximum of 3 single or multiple layers of welded wire fabric or steel bars. The welded wire fabric shall be composed of circumferential and longitudinal wires which are in accordance with the spacing requirements shown herein. The ends of the longitudinal reinforcement shall not be more than 50 mm (2 in.) from the ends of the culvert section. The exposure of the ends of longitudinal reinforcement and spacers used to position the reinforcement shall not be cause for rejection.

3. REINFORCEMENT DEVELOPMENT, SPLICES, AND SPACINGS. Exterior corner reinforcement shall be fully developed or extended 300 mm (12 in.) past the point of peak stress. For deformed steel bars, equal-leg 90 degree bends shall have leg lengths as shown on the plans. The development length for welded wire fabric shall be in accordance with the AASHTO Standard Specifications for Highway Bridges.

Splices in circumferential reinforcement shall be made by means of lapping and not by means of welding. Lap lengths shall be in accordance with the AASHTO Standard Specifications for Highway Bridges.

The center to center spacing of the circumferential wires in a fabric sheet shall not be less than 50 mm (2 in.) nor more than 100 mm (4 in.). The center to center spacing of the longitudinal wires or bars shall not be more than 200 mm (8 in.). If circumferential reinforcement is composed of bars, crack control criteria shall be checked. Calculations performed by a registered professional engineer which verify that the proposed bar spacings are in accordance with the crack control criteria shall be submitted to the Engineer.

(c) MANUFACTURE.

1. MIXTURE. Aggregates, cement, and water shall be proportioned and mixed in a batch mixer to produce a homogeneous concrete, with compressive strength in accordance with the requirements shown herein. The proportion of portland cement shall not be less than 334 kg/m3; (564 lb/cu yd) of concrete. The concrete shall contain 6.5 " 1.5 percent entrained air.

2. FORMS. The forms shall be rigid and accurate to maintain the culvert dimensions within the permissible variations shown herein. All casting surfaces shall be of a smooth material.

3. CURING. The culvert shall be cured for a length of time so that the concrete develops the specified compressive strength in 28 days or less. One of the following methods of curing or a combination thereof shall be used.

a. STEAM CURING. The culvert sections may be low pressure, steam-cured by means of a system that shall maintain a moist atmosphere.

b. WATER CURING. The culvert sections may be water cured by means of a method which shall keep the sections moist.

4. FORMS LEFT IN PLACE. An accelerated overnight cure accomplished through the use of an external heat source may be used provided moisture loss from exposed surfaces is minimized. The maximum temperature increase or decrease shall be 22NC (40NF) per hour. The initial application of the heat shall occur 2 hours after the final placement of concrete to permit the initial set to take place.

5. HANDLING. Handling devices or holes shall be placed in each culvert section. However, not more than 4 holes shall be cast or drilled in each section. The holes shall be tapered unless drilled. Before backfilling, the tapered holes shall be filled with portland cement mortar, or with precast concrete plugs which shall be secured with portland cement mortar or other approved adhesive. Drilled holes shall be filled with portland cement mortar. Holes shall be covered on the exterior with joint wrap material. Such wrap material shall have a minimum length and width of 230 mm (9 in.).

(d) PERMISSIBLE VARIATIONS.

1. INTERNAL DIMENSIONS. The internal dimensions shall not vary more than 50 mm (2 in.) from the design dimensions. The haunch dimensions shall not vary more than 19 mm (3/4 in.) from the design dimensions.

2. DECK AND WALL THICKNESSES. The deck and wall thicknesses shall not be less than those shown in the design by more than 19 mm (3/4 in.). A thickness of more than that required by the design shall not be cause for rejection.

3. LENGTHS OF OPPOSITE SURFACES. Variations in laying lengths of 2 opposite surfaces of the culvert section shall not be more than 25 mm (1 in.), except where beveled ends for laying of curves are specified.

4. LENGTH OF SECTION. The underrun in the length shall not be more than 13 mm (2 in.).

5. POSITION OF REINFORCEMENT. The maximum variation in position of the reinforcement shall be " 15 mm (3/8 in.). The cover over the reinforcement for the external surface of the top slab shall not be less than 50 mm (2 in.) for earth covers of less than 0.9 m (3 ft). These tolerances or cover requirements will not apply to mating surfaces of the joint.

6. AREA OF REINFORCEMENT. The areas of steel reinforcement shall be the design steel areas per meter (linear foot) of culvert section. Steel areas of greater than those required shall not be cause for rejection. The permissible variation in diameter of reinforcement shall be in accordance with the tolerances shown in the ASTM specification for that type of reinforcement.

(e) MARKING. The following information shall be clearly marked on the interior of each culvert section by means of indentation, waterproof paint, or other approved means.

1. Culvert span and rise

2. Design earth cover

3. Date of manufacture

4. Name or trademark of the manufacturer

 

(f) TESTING.

1. TEST SPECIMEN. Concrete compressive strength shall be determined from compression tests made on cores. For each continuous production run, each group of 15 culvert sections of a single size or a fraction thereof shall be considered separately for the purpose of testing and acceptance. A production run shall be considered continuous if it is not interrupted for more than 3 consecutive days.

2. COMPRESSION TESTING. Cores shall be obtained and tested for compressive strength in accordance with ASTM C 497. One core shall be cut from a section selected at random from each group of 15 culvert sections or fraction thereof for a single size from each continuous production run.

3. ACCEPTABILITY OF CORE TESTS. The compressive strength of the concrete in each group of culvert sections defined above will be acceptable when the core test strengths are equal to or greater than the design concrete strength.

If the compressive strength of the core tested is less than the design concrete strength, the culvert section from which that core was taken may be cored again. If the compressive strength of the new core is equal to or greater than the design concrete strength, the compressive strength of the concrete in that group of culvert sections will be acceptable.

If the compressive strength of a new core is less than the design concrete strength, the culvert section from which that core was taken will be rejected. Two culvert sections from the remainder of the group shall be selected at random. One core shall be taken from each. If the compressive strength of both cores is equal to or greater than the design concrete strength, the compressive strength of the remainder of that group of culvert section will be acceptable. If the compressive strength of either of the 2 cores tested is less than the design concrete strength, each culvert section of the remainder of the group shall be cored and accepted individually. The culvert sections which have cores with less than the design concrete strength will be rejected.

4. PLUGGING CORE HOLES. The core holes shall be plugged and sealed by the manufacturer so that the culvert section shall be in accordance with all test requirements shown herein. Culvert sections so sealed will be considered satisfactory for use.

5. CORING EQUIPMENT. The culvert manufacturer shall furnish the equipment and personnel necessary to obtain the cores.

(g) INSPECTION. The quality of materials, the process of manufacture, and the finished culvert shall be subject to inspection by the Engineer.

(h) REJECTION. Culvert sections shall be subject to rejection if they are not in accordance with the specification requirements. A culvert section may be rejected due to the following conditions.

1. Fractures or cracks pass through the slab or wall

2. Defects which indicate imperfect proportioning, mixing, or forming

3. Honeycombed or open texture

4. Damaged section ends, where such damage prevents making a satisfactory joint

 

(i) REPAIRS. Culverts may be repaired, if necessary, due to imperfections in manufacture, handling damage, or construction. Repairs will be acceptable if it is determined that the repairs are sound, properly finished and cured, and if the repaired culvert section is in accordance with the requirements shown herein.

(j) CONSTRUCTION REQUIREMENTS.

1. WATERPROOFING. The back of the joint between the culvert and the wingwall shall be waterproofed in accordance with 702.23.

2. SEALING. Sealer shall be epoxy penetrating sealer in accordance with 909.09 or an approved proprietary concrete sealer in accordance with 909.10. Sealer shall be applied on the top surface of the culvert. Such sealer shall extend 1.5 m (5 ft) vertically down the sides, except in the keyway. The sealer shall be provided for the full length of the structure. Surface preparation and application procedures shall be as recommended by the sealer manufacturer.

3. JOINTS. The culvert sections shall be produced with a grout filled keyway. The keyway shall provide a void which shall be a minimum of 100 mm (4 in.) wide. The keyway surfaces shall be given a medium sandblast, a water blast at 14 kPa (2,000 psi), or a thorough wire brushing at the plant within 4 days before the culvert sections are taken from the plant. The ends shall be of such design and shall be so formed that when the culvert sections are laid together, they shall make a continuous line of culvert with a smooth interior free of irregularities, all compatible with the permissible variations shown herein.

Mortar for the keyway shall be a non-shrinking non-metallic mortar with a minimum compressive strength at 28 days of 34.5 kPa (5,000 psi) in accordance with the Corps of Engineers Specification CRD-C621 when prepared to a moderate fluidity of 124 to 145 percent at 5 drops. The mortar shall also be in accordance with all other requirements of Specification CRD-C621. The mortar shall be prepared, placed, and cured in accordance with the manufacturer's recommendations. Before mortaring, the keyway shall be thoroughly cleaned of all dirt, dust, or other foreign matter. The keyway surfaces shall be wetted. However, no free water shall be permitted to remain in the keyway.

The joint exterior shall be covered with a wrap of minimum width of 230 mm (9 in.) centered on the joint. The external wrap shall be in accordance with ASTM C 877. The joint wrap shall be kept in its proper location during backfilling.

4. WORKMANSHIP AND FINISH. The culvert shall be free of fractures. All surfaces shall have a smooth finish. The ends of the culvert sections shall be normal to the walls and centerline within the limits of the permissible variations shown herein, except where beveled ends are specified.

5. BACKFILLING. Backfill material within the limits shown on the plans shall be B borrow for structure backfill in accordance with 211. A layer of compacted granular material of 100 mm (4 in.) thickness shall be prepared for the full width of the wingwall footing prior to placing the wingwall footing.

METHOD OF MEASUREMENT. Culverts will be measured by the meter (linear foot), complete in place. Footings and wingwalls will be measured as concrete in accordance with 702.27 and reinforcing steel in accordance with 703.07.

BASIS OF PAYMENT. The accepted quantities of culvert will be paid for at the contract unit price per meter (linear foot) for culvert, precast 3-sided, reinforced concrete, of the span and rise specified, complete in place. The quantities for payment shall remain as shown on the plans even if the Contractor chooses the other culvert option.

The accepted quantities of footings and wingwalls will be paid for as concrete in accordance with 702.28 and reinforcing steel in accordance with 703.08. If footings or wingwalls are constructed of precast concrete, payment will be made based on the plan quantites of concrete and reinforcing steel.

 

Payment will be made under:

Metric Pay Item ---------------------------------------------------------------------Metric Pay Unit Symbol

(English Pay Unit -----------------------------------------------------------------English Pay Unit Symbol)

Culvert, Precast 3-Sided, Reinforced Concrete,

_____ mm x _____ mm. m
-span ----------rise

(Culvert, Precast 3-Sided, Reinforced Concrete,
_____ in. x _____ in. (LFT)
span ---------rise

 

The costs of testing, plugging cores, reinforcing steel, additional fill, subsequent excavation required to provide the minimum cover, repairs, and necessary incidentals shall be included in the costs of the pay items.