6-14 Reinforcing Steel 709.01 Stone Curbing and Edging 712.04 Precast Concrete Units 712.06 Tops and Traps 712.07 C o r r u g a t e d M e t a l U n i t s 712.08 Catch Basin and Manhole Steps 712.09 Except as otherwise provided on the plans, concrete for these s tructures shall meet the requirements of Section 502 - Structural Concrete. Catch basin grates shall be either the type of grate shown on t he Standard Details or an approved equal. The corners s hall be notched by the Contractor at the project site by grinding the corner to fit the cast iron frames.
604.03 Construction Requirements Concrete catch basins and man holes shall be
constructed of precast units, except that concrete blocks may b e used around inlet and outlet pipes. Joints for precast concrete units shall be of Portland cement mortar, rubber gaskets, flexible plastic rings, mastic joint filler or other approved t ypes to form a watertight joint. Joints for concrete blocks shall be of Portland cement mortar, not more than ½ inch wide, completely filled and neatly tooled on the inside of the struct ure. Metal catch basins shall be corrugated metal pipe units mounte d on a Portland cement concrete foundation. Catch basins and manholes shall be placed to the required grad e on a compacted foundation of uniform density. Inlet and outlet pipe elevation s may vary from the elevations shown on the plans depending upon field conditions. Pipe sections entering catch basins shall be firmly connected to the structure wall with no part of the pipe projecti ng more than 6 inches inside t he wall. When a section of culvert is cut, the end shall be finished in a skillful manner. Metal frames and traps, when called for, shall be set in a bed of clay bricks or shale bricks and mortar, or otherwise secured as shown on the plans. Castings shall be set to the correct elevation before the next final course of paving materi al has been placed. Upon completion, each catch basin and manhole shall be cleaned of all accumulation of silt, debris, or foreign matter and shall be kept clean unti l final acceptance of the work.
604.04 Altering, Adjusting, and Rebuilding Catch Basins and Man holes Existing catch
basins and manholes shall be dismantled sufficiently to allow a ltering, adjusting, or rebuilding in accordance with the applicable requirements as sh own on the Standard Detail plans for complete catch basins and manholes. When existing fr ames, covers, and grates are used, they shall be thoroughly clean ed of existing mortar befor e placing to the new grade. 6-15
a.Altering Catch Basin The existing top assembly shall be rem oved and replaced with a new Type A or Type B frame and special grate set to the require d grade using approved clay brick and mortar.
b.Adjusting Catch Basins and Manholes The existing top assemb ly shall be removed, thoroughly cleaned, and reset to t he new grade using approved c lay brick and mortar. The Department will allow the use of metal ring inserts set into th e manhole top frame or composite risers placed beneath the manhole frame to adjust man hole slope and grade for paving projects. The use of metal ring inserts shall be in acc ordance with 604.04 d. Ring Insert Requirements. The use of composite risers shall be in a ccordance with 604.04 e. Composite Riser Requirements.
c.Rebuilding Catch Basins and Manholes The existing top assem bly, cone section, and barrel section shall be removed down to the outlet flow line gr ade to the extent required, as determined by the Resident, and shall be rebuilt and a new fram e and grate furnished and installed at the required line and grade directed. Concrete bl ocks may be used to rebuild the barrel section, if necessary, due to existing conditions. The Department will allow the use of metal ring inserts set int o the manhole top frame or composite risers placed beneath the manhole frame to adjust man hole slope and grade for paving projects. The use of metal ring inserts shall be in acc ordance with 604.04 d. Ring Insert Requirements. The use of composite risers shall be in a ccordance with 604.04 e. Composite Riser Requirements.
d.Ring Insert Requirements Ring inserts to adjust manhole top frame slope and grade will are allowed in accordance with the following requirements:
1.Materials i All ring inserts must be made of iron. Multiple ring inserts will not be allowed. The single ring insert may be any height up to a maximum of 2 i nches tall. ii Ring inserts shall not be welde d to the manhole frame to pre vent brittle failure of the cast iron frame. iii Ring inserts shall be fastened to the manhole frame using l iquid steel-filled epoxy such as Loctite Fixmaster Steel Liquid or equivalent. The epoxy shall be installed in accordance with the manufacturer’s recommendations .
2.Where Ring Inserts May/May Not Be Used i The Department will allow the use of a single manhole ring in sert to raise manholes on state and state-aid highways. 6-16 ii Manhole ring inserts may not be used al ong state and state-aid highway sections where the speed limit is 40 miles per hour or more. The standard brick and mortar or flat composite risers beneath the manhole frame must be used at these locations.
3.Construction Requirements For The Use of Iron Manhole Ring Inse rts i Wherever iron ring inserts are used to raise manhole top elev ations, the rings shall be fastened to the existing manhole frame using liquid st eel-filled epoxy. The liquid steel-filled epoxy shall be placed evenly around the entire manhole frame before placing the ring insert. Unbonded ring inserts will not be allowed . If the manufacturer’s recommended construction practices result in loose or unacceptable manhole cover restraint, standard brick and mortar or flat composite risers beneath the manhole frame must be used at these location s.
e.Composite Riser Requirements Flat or beveled, doughnut-shap ed, composite risers placed beneath the manhole frame to adjust slope and grade are allowed. The composite riser shall be fastened to both the top of the concrete cone an d bottom of the manhole frame with the manufacturer’s recommended epoxy. Composite risers ma y be used at all locations on state and state-aid highways under any legal speed limit wit hout restriction. All salvaged material not reused, including grates, and frames , and curb inlets will remain the property of the present owner unless otherwise speci fied. Each catch basin and manhole altered, adjusted, or reconstruct ed, shall be cleaned of all accumulated silt, debris, and other foreign matter before f inal acceptance of the work. Resetting the curb inlet will be included in the adjusting or r ebuilding catch basin items
604.05 Method of Measurement Catch basins, manholes, and acces sories of the
respective types will be measured by the number of units, measu red as follows, complete, and accepted in place.
a.Complete Structures Each catch basin and manhole having a d epth up to 8 feet from the top of the grate or cover t o the top of the floor, measured to the nearest foot, will be one unit. ⅛ of a unit will be added for each additional foot over 8 feet measured to the nearest foot. Depth measurements in excess of the dimensions authorize d will not be included.
b.Existing Structures Existing catch basins and manholes to b e altered, adjusted or rebuilt will be one unit each. Existing catch basins and manho les that are cleaned will be one unit each.
c.Trap Each trap included in the completed structure will be one unit each.
d.Step Each step included in the completed structure will be one unit each. 6-17
e.Grate Each grate changed under item 604.167 will be measure d by each unit, complete in place and accepted.
604.06 Basis of Payment The accepted quantities of catch basin s, manholes, altered
grates, traps, and steps, will be paid for at the contract unit price each of the respective types complete in place. Payment for rebuilding, adjusting or alteri ng catch basins and manholes shall include furnishing all materials including new blocks, br icks, mortar, metal tops, covers, and curb inlets when required. Frames, grates, and cov ers for new or rebuilt catch basins or manholes shall be considered part of the structure an d no separate payment will be made. Payment for cleaning existing catch basins and manholes will be paid for at the contract unit price each. There will be no payment for cleanin g new, altered, adjusted, or rebuilt catch basins and manholes. Payment will be full compen sation for supplying all equipment and labor to clean the basins and manholes and to dis pose of the waste. Excavation and backfill will be considered incidental, except as provided in Section 206 - Structural Excavation. Payment will be made under: P a y I t e m P a y U n i t 604.072 Catch Basin Type A1-C Each 604.082 Catch Basin Type A2-C Each
604.09 Catch Basin Type B1 Each
604.092 Catch Basin Type B1-C Each 604.096 60”Catch Basin Type B1-C Each 604.097 72”Catch Basin Type B1-C Each
604.10 Catch Basin Type B2 Each
604.102 Catch Basin Type B2-C Each
604.11 Catch Basin Type C1 Each
604.12 Catch Basin Type C2 Each
604.13 24 inch Catch Basin Type E Each
604.14 30 inch Catch Basin Type E Each
604.15 Manhole Each
604.16 Altering Catch Basin to Manhole Each
604.161 Altering Catch Basin Each 604.164 Rebuilding Catch Basin Each 604.166 Rebuilding Manhole Each 604.167 ChangeCatch Basin Grate to Cascade Grate Each 604.17 Altering Manhole to Catch Basin Each
604.18 Adjusting Manhole or Catch Basin to Grade Each
604.182 Cleaning Existing Catch Basin and Manhole Each
604.19 8 inch Trap Each
604.20 12 inch Trap Each
604.21 15 inch Trap Each
604.22 18 inch Trap Each
Source: Maine Standard Specifications for Road and Bridge Construction, 2020 Edition. Pages 484–487 of 817.