8-8 Section 803. Concrete Sidewalk, Curb Ramps, and Step s
803.01 Description
The work consists of constructing concrete sidewalks, curb ramps, and steps.
803.02 Materials
Provide materials in accordance with the following sections : Sound Earth .......................................................................................... 205 Granular Material Class II ..................................................................... 902 Curing Compound ................................................................................. 903 Steel Reinforcement ............................................................................. 905 Pipe Railing ........................................................................................... 908 Joint Fillers ............................................................................................ 914 Concrete, Grade 3000, 3500 ............................................................... 1004 Grout ................................................................................................... 1005
A.Steps . Use Grade 3500 for concrete for steps . Precast steps will be allowed.
B.Detectable Warning Surfaces. Provide pre-fabricated detectable warning surf aces selected from the Qualified Products List that contrast visually with adjacent walking surfaces, either light -on-dark or dark-on-light . Base the selection on whether the detectable warning surface will be installed on existing concrete or on newly cas t concrete. Ensure that the surface -applied products include mechanical anchors.
803.03 Construction
A.Preparation of Base. Excavate to the required depth and to a width that will allow forming . Remove unsuitable material below the required depth and replace with sound earth. Shape base to conform to the section shown on the plans and compact to 95% .
B.Forms . Use either fixed forms or slip forms . Provide straight, full -depth, unwarped forms that will resist springing during concrete placement . Firmly stake fixed forms.
C.Placing and Finishing Concrete . Wet the base before placing concrete. Do not place concrete on a frozen base or on a base that is unstable from excessive moisture . Place the concrete and consolidate before finishing. Place and finish concrete in a continuous operation. If replacing gutters in addition to curb ramp s, transition the gutter cross section in advance of the curb ramp to meet the dimension and profile in MDOT Standard Specifications for Construction Section 803 8-9 the MDOT Standard Plan R -28 series . Use the same reinforcement pattern present in the existing gutter. Place the railing sockets for concrete steps in the plastic concrete or drill into the hardened concrete. Float the surface to produce a smooth surface, free from irregularities . Round the edges and joints with a finishing tool. Texture t he surface of sidewalks , curb ramp s, driveways , and steps with a coarse broom transverse to the direction of travel. Do not stamp, stencil, or in any way mark concrete with a company name, logo, or other such information.
D.Sidewalk Joints. Construct transverse and longitudinal expansion and plane-of -weakness joints at intervals and locations shown in the MDOT Standard Plan R -29 series . Align transverse joints with like joints in adjacent slabs . Construct joints with faces perpendicular to the surface of the sidewalk and no greater than ¼ inch from the position shown on the plans . Construct transverse joints at right angles to the centerline of the sidewalk and longitudinal joints parallel to the centerline. Spade or vibrate and compact the concrete to fill voids at the faces of the joints . Place expansion joint filler the full depth of the joint . Recess the top of the joint filler ¼ to ½ inch below the finished surface. Cut the plane- of-weakness joints into the concrete after floating. Cut plane-of -weakness joints to at least one-fourth the thickness of the sidewalk and from ⅛ to ¼ inch wide. Do not seal the joints.
E.Curing and Protection . Cure and protect the concrete in accordance with subsection 602.03.M and subsection 602.03.T .
F.Railing for Steps . Place the railing in the sockets and fill the space between the pipe and the socket with a non-shrink mortar or grout selected from the Qualified Products List . Provide bracing as needed for the railing to remain plumb while the grout achieves the proper strength.
G.Backfilling. After the concrete gains the needed strength, remove fixed forms and backfill with sound earth. Compact and level the backfill 1 inch below the concrete surface.
H.Detectable Warning Surfaces. Install detectable warning surfaces in accordance with the manufacturer’s instructions and the MDOT Standard Plan R -28 series. MDOT Standard Specifications for Construction Section 803 8-10 I. Curb Ramp Opening . Construct curb ramp openings in accordance with subsection 802.03, the MDOT Standard Plan R -28 series , and as required to conform with the curb ramp geometry including, but not limited to, slopes, counter slopes, running slopes, cross slopes, flares, and widths.
803.04 Measurement and Payment
Pay Item Pay Unit Sidewalk, Conc, __ inch ................................................................ Square Foot Curb Ramp, Conc, __ inch ............................................................ Square Foot Detectable Warning Surface ...................................................................... Foot Steps, Conc ..................................................................................... Cubic Yard Railing for Steps ........................................................................................ Foot Curb Ramp Opening, Conc ...................................................................... Foot
A.Concrete Acceptance. Conduct concrete QC as specified in section 1002. The Engineer will conduct QA as specified in section 1003. The Department will a pply adjustments to this work based on the QA results.
B.Sidewalk, Concrete. The Engineer will measure Sidewalk, Conc , __ inch of the required thickness, in place.
C.Curb Ramp . The Engineer will measure Curb Ramp, Conc, __ inch by the area of ramp and landing in place. Curb Ramp , Conc, __ inch includes sidewalk sloped greater than the normal continuous sidewalk grades to meet the elevation of the curb opening or intermediate landing. Landing areas constructed and meeting the requirements of the MDOT Standard Plan R -28 series will be included in the Curb Ramp , Conc, __ inch item. The unit price for Curb Ramp, Conc , __ inch includes the cost of landings, monolithic rolled curbs or side flares along the longitudinal edges of the ram p or landing, and transitions to existing sidewalk . The Department will pay separately for replacing sidewalks, curbs, or curb and gutter outside the area measured for Curb Ramp , Conc, __ inch . The Department will pay for rolled curb adjacent to the non -traffic edge of parallel or combination ramps separately only if the required height exceeds 18 inches along a continuous run.
D.Detectable Warning Surface. The Engineer will measure Detectable Warning Surface in place by length along the center of the 24-inch-wide detectable warning surface material at required locations . The unit price MDOT Standard Specifications for Construction Section 803 8-11 for Detectable Warning Surface includes the cost of surface preparation and application .
E.Steps, Concrete. The Engineer will measure and the Department will pay for Steps, Conc based on plan quantities in accordance with subsection
109.01 The unit price for Steps, Conc includes the cost of foundation
preparation; constructing forms ; providing and placing steel reinforcement ; providing, placing, finishing, and curing concrete; providing and placing backfill; and cleanup. The Engineer will measure Railing for Steps in place by length of top rail for each railing required. The unit price for Railing for Steps includes the cost of providing, fabricating, installing, and grouting the railing.
F.Excavation and Backfill . Unless the contract includes separate pay items for excavation and backfill, the unit price for other items of work will include the cost of excavation and backfilling .
G.Curb Ramp Opening, Conc . The Engineer will measure Curb Ramp Opening, Conc in place along the joint between the curbing with the pavement including transitions to and from adjacent standard full -height curb and gutter cross section.
Source: Michigan Standard Specifications for Construction, 2020 Edition. Pages 569–572 of 1,146.