DelDOT Section 602: Drainage Structures

602.1Description.

This work consists of constructing, providing, replacing, adjusting, and repairing drainage inlets, drainage inlet frames and grates, manholes, manhole frames and covers, and junction boxes.

602.2Materials.

A.GABC Section 1005

B.PCC, Class A or B Section 1022

C.Expansion Joint Material Section 1042.2.A

D.Bar Reinforcement Section 611 and Section 1037

E.Liquid Membrane-Forming Compounds for Curing Section 1022

F.Welding AASHTO / AWS D1.1 Welding Code

G.Castings Section 1039.7

H.Steps AASHTO M199 and ASTM C478

I.Borrow, Type C Section 1001

J.Joint Sealant Section 1042.2.B

K.Non-Shrink Grout Section 1047.2

L.Mortar Section 1047.6

M.Silane-Based Concrete Sealer Section 1045.3

N.Precast Flexible Joint Sealant Section 1042.5

O.Drainage Structure Grates and Covers Section 1039.11

602.3Construction.

For precast elements, adhere to the General Manufacturing Requirements of Section 612.3.2.

A.Shop Drawings

1.Submit shop drawings that include quantities and locations for installations not meeting

Standard Construction Details before fabrication for:

a.Drainage inlets, manholes, and junction boxes. Include design calculations ensuring the

proposed structure can handle all loads including the HS-20 live load.

b.Drainage inlet frames and grates, and manhole frames and covers.

c.Drainage inlet frames, manhole frames, and junction boxes that require adjustments or repair.

2.For locations that require repair, adjustments, or replacement, include field measurements to

determine the exact sizes of the drainage inlet frames and grates, and manhole frames and covers before placing the order.

3.For locations that require the repair of existing junction boxes, include field measurements to

determine the exact sizes of the top cover slab and hinge. Also include all parts and fittings for installation.

B.Constructing Drainage Inlets, Manholes, and Junction Boxes

1.Refer to shop drawings, contract documents, or Standard Construction Details for dimension

and structure requirements.

2.Use PCC, Class A for all drainage structures.

3.Excavate and backfill in accordance with Section 207.3. Compact the structure foundation to a

firm, even surface, to the acceptance of the engineer.

4.Use cast-in-place construction for drainage structures that tie into existing pipes and structures

unless otherwise specified in the contract. The contractor may request use of precast structures subject to the engineer’s approval. Use precast structures for new construction unless otherwise specified in the contract.

5.Construct cast-in-place reinforced concrete structures in accordance with Section 610.

6.Provide precast reinforced concrete round manhole riser sections and appurtenances in

accordance with AASHTO M199.

7.Set the frames of castings in concrete.

8.For drainage inlets, manholes, and junction boxes that use a removable top slab or are 4-feet or

deeper when measured from the top of grate or cover to the invert of the lowest pipe, install steps at an accessible location. Ensure that the steps have a minimum embedment of 3-inches into the wall and protrude out 6-inches from the wall. Begin steps within 24-inches of the top of grate or lid and place the last step no more than 12-inches above the lowest invert except where a pipe is in the backwall. Place steps vertically 12-inches apart.

9.Ensure inlet and outlet pipes are the same size and type as the connecting pipes shown in the

contract and that pipes extend through, and are flush with, the inside of the wall. When cutting off the end of a reinforced concrete pipe, finish with mortar so that no reinforcement steel remains exposed. Fill any space between the pipe and the walls of the drainage inlet with non- shrink grout conforming to the requirements of Section 1047, with a minimum strength of 5,000-PSI. Ensure that the pipe opening in the drainage inlet is no more than 4-inches larger than the pipe diameter measured from the outside wall of the pipe.

10.Construct, finish, and cure cast-in-place structures other than top units in accordance with

Section 610.3.6.

11.Construct, finish, and cure the structure top units in accordance with Sections 501.3 or 503.3.

12.Pour the flow channel to provide positive flow. Cure the flow channel with materials in

accordance with Section 1022.6 except water curing will not be permitted.

13.Backfill the area around drainage inlets and manholes with Borrow Type C material in

accordance with Section 207.

14.Prepare surface exposed concrete ahead of sealing in accordance with Section 613.3.B. Seal

surface exposed concrete with silane sealer meeting the requirements of Section 1045.3 in accordance with Section 613.3.D.

C.Remove existing and provide new grates and frames for repair and adjustments of drainage Inlets,

manholes and junction boxes.

D.Adjusting and Repairing Drainage Inlets, Manholes, and Junction Boxes.

1.Adjusting.

a.Supply and install solid adjustment ring in accordance with the utility owner’s

recommendation.

b.Adjust with top unit in accordance with the Standard Construction Details as follows:

i.Saw cut existing bituminous concrete or PCC pavement for top unit installation in

accordance with the Standard Construction Details. ii. Excavate materials from the perimeter in accordance with Section 207.3. Dispose of waste materials in accordance with Section 106.8. iii. Remove existing castings. Clean and set castings aside for reuse or replacement in accordance with the contract. If the engineer determines that the casting is damaged and not suitable for reuse, provide a new casting in accordance with Section 602.3.B iv. Place forms for the top unit to accommodate the replacement frame.

v.Do not place the frame on bricks, blocks, or other materials.

vi. Place required steel reinforcement and encase in PCC, Class B. Cure in accordance with Sections 501.3 or 503.3. vii. Prepare surface exposed concrete ahead of sealing in accordance with Section 613.3.B. Seal surface exposed concrete with a silane sealer meeting the requirements of Section 1045.3 in accordance with Section 613.3.D viii. Take removed drainage inlet frames, grates, manhole frames, and covers, to the Department's District Maintenance Yard or to a location specified in the contract. ix. Seal joints in accordance with Section 504.

2.Repairing.

a.Remove covers of drainage inlets or manholes for inspection by the engineer.

b.If the engineer determines the structure is in good condition, adjust the castings according to

Section 602.3.D.

c.If the engineer determines the existing structure is in poor condition, repair as directed by the

engineer.

d.Backfill the area around drainage inlets and manholes with Borrow Type C material in

accordance with Section 207.

e.Backfill the area around drainage inlets and manholes with GABC in accordance with Section

301.

f.Install steps in an accessible location in drainage inlets or manholes as needed in accordance

with Section 602.3.B.8.

g.If a new flow channel is needed, ensure positive flow when constructing the channel.

3.Connect pipes to drainage inlets, manholes, and junction boxes in accordance with Section

602.3.B.9 and as directed by the engineer.

602.4Method of Measurement.

A.The Department will measure the quantity of drainage inlets, manholes, and junction boxes as the

number of each installed and accepted. The Department will measure inlet and outlet pipes with the adjoining pipe. The Department will not measure frames and grates and will consider these items as included in the drainage inlet, manhole, or junction box items.

B.The Department will measure the quantity of provided drainage inlets and manholes grates and

frames as the number of each placed and accepted.

C.The Department will measure the quantity of adjusted and repaired existing drainage inlets,

manholes, and junction boxes as the number of each adjusted or repaired and accepted.

D.The Department will measure the quantity of special drainage inlets, special junction boxes, and

special manholes placed as the number of each.

E.The Department will not measure the quantity of special drainage inlets, special junction boxes,

and special manholes placed and accepted measured as lump sum.

F.The Department defines the template as 24-inches outside the neat-line perimeter of drainage

inlets, manholes, and junction boxes.

602.5Basis of Payment.

A.The Department will pay the quantity of the drainage inlet, special drainage inlets, manholes, and

junction boxes at the contract unit price. Price and payment will constitute full compensation for:

1.Excavating within the template of the item;

2.removal and disposal of existing materials;

3.foundation preparation and compaction;

4.providing and placing materials;

5.forms and forming;

6.supplying, placing, finishing, curing, and sealing PCC;

7.constructing inlet hoods;

8.joints;

9.backfilling;

10.removing surplus materials; and

11.removing and replacing cracked or damaged drainage inlets, special drainage inlets, manholes,

and junction boxes.

B.The Department will pay the quantity of grates and frames at the contract unit price of each. Price

and payment will constitute full compensation for supply, replacement, and disposal of the existing materials.

C.The Department will pay the quantity of adjusted and repaired existing drainage inlets, manholes,

and junction boxes at the contract unit price of each. Price and payment will constitute full compensation for:

1.Sawcutting;

2.excavating within the template of the item;

3.removal and disposal of existing materials;

4.foundation preparation and compaction;

5.providing and placing materials;

6.forms and forming;

7.supplying, placing, finishing, curing, and sealing PCC;

8.joints;

9.expansion joint material;

10.sealing;

11.backfilling;

12.removing surplus materials; and

13.removing and replacing cracked or damaged drainage inlets, manholes, and junction boxes.

D.The Department will pay for adjust and repair to the depth of the adjustment as follows:

1.The contract unit price for units repaired from the top of the unit frame to a depth 3-feet below

the frame.

2.One and a half times the contract unit price for units repaired to a depth ranging from 3-feet

below the frame to 4 1/2-feet below the frame.

3.Double the contract unit price for units repaired more than 4 1/2-feet below the frame.

4.Work to adjust or repair flow channels and install steps is excluded from depth of repair

payment adjustments.

E.The Department will pay for bituminous pavement patching in accordance with Section 401.

F.Submit the breakout sheet included in the proposal for lump sum items in accordance with

Section 109. ITEM DESCRIPTION UNIT 602000 DRAINAGE INLET, 17.625” X 11.625” EA 602001 DRAINAGE INLET, 24” X 24” EA 602002 DRAINAGE INLET, 34” X 18” EA 602003 DRAINAGE INLET, 34” X 24” EA 602004 DRAINAGE INLET, 48” X 30” EA 602005 DRAINAGE INLET, 48” X 48” EA 602006 DRAINAGE INLET, 66” X 30” EA

602007 DRAINAGE INLET, 66” X 48” EA 602008 DRAINAGE INLET, 66” X 66” EA 602009 DRAINAGE INLET, 72” X 24” EA 602014 DRAINAGE INLET, 72” X 36” EA 602010 DRAINAGE INLET, 72” X 48” EA 602011 DRAINAGE INLET, 72” X 72” EA 602012 DRAINAGE INLET, SPECIAL EA 602013 DRAINAGE INLET, SPECIAL LS 602030 MANHOLE, 48” X 30” EA 602031 MANHOLE, 48” X 48” EA 602032 MANHOLE, 66” X 30” EA 602033 MANHOLE, 66” X 48” EA 602034 MANHOLE, 66” X 66” EA 602035 MANHOLE, ROUND EA 602036 MANHOLE, SPECIAL EA 602037 MANHOLE, SPECIAL LS 602060 JUNCTION BOX, 48” X 30” EA 602061 JUNCTION BOX, 48” X 48” EA 602062 JUNCTION BOX, 66” X 30” EA 602063 JUNCTION BOX, 66” X 48” EA 602064 JUNCTION BOX, 66” X 66” EA 602065 JUNCTION BOX, SPECIAL EA 602066 JUNCTION BOX, SPECIAL LS 602100 DRAINAGE INLET GRATE(S) EA 602101 DRAINAGE INLET FRAME(S) EA 602102 MANHOLE GRATE(S) EA 602103 MANHOLE FRAME(S) EA 602130 ADJUSTING AND REPAIRING EXISTING DRAINAGE INLET EA 602131 ADJUSTING AND REPAIRING EXISTING DOUBLE DRAINAGE EA 602132 ADJUSTING AND REPAIRING EXISTING MANHOLE EA 602133 ADJUSTING AND REPAIRING EXISTING JUNCTION BOX EA

Referenced in this section

Sections that cite this one

910STORMWATER MANAGEMENT FACILITIES

DRAINAGE STRUCTURES in other states

Get an email when 602 changes

Delaware revises spec sections through supplementals and new editions. We check this one every week and email you the day it changes. Free, no account.

Source: Delaware Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 184–0 of 786. View official source ↗

← Previous

601 PIPE CULVERTS

604 TEMPORARY WORKS

602DRAINAGE STRUCTURES

Ask about Section 602