7-115 Section 711. Bridge Railings
711.01 Description
This work consists of providing and constructing bridge railings as shown in the contract.
711.02 Materials
Provide materials in accordance with the following sections : Concrete Curing Material ...................................................................... 903 Dowels and Bar Reinforcement ............................................................ 905 Structural Steel ..................................................................................... 906 Miscellaneous Metals ............................................................................ 908 Tubing, Steel Railing ............................................................................. 908 Hardware for Timber Construction ........................................................ 908 Structural Timber and Lumber ............................................................... 912 Preservative Treatments ....................................................................... 912 Expansion Bolts .................................................................................... 914 Barrier Reflector Markers ...................................................................... 922 Concrete, Grade 4500, 4500HP .......................................................... 1004 Provide Grade 4500HP concrete for high- performance railings . Provide Grade 4500 concrete for all other railing concrete. Provide natural aggregate with a maximum absorption of 2.50% in accordance with ASTM C127. Do not use slag aggregate.
711.03 Construction
Do not slip form concrete railings.
A.Structural Steel and Pi pe Railings . Shop drawings for structural steel and pipe railings are not required. Construct railing in accordance with section 707. Adjust metal railing before bolting connections to ensure that abutting joints match and align throughout the railing length. Fabricate and weld in accordance with section 707. Perform NDT of welds in accordance with subsection 707.03.D.12. Blast clean welded post assemblies before galvanizing. Shop clean and coat hot -dip galvanized structural steel railing in acc ordance with section 716 if shown in the contract . After galvanizing, do not punch, drill, cut, or weld steel railing components . Only weld end caps and longitudinal seams made by the manufacturer . If the plans do not show or imply dimensional tolerances, MDOT Standard Specifications for Construction Section 711 7-116 apply tolerances consistent with manufacturing practices and part function, including appearance. Roll and bend tube rail sections with a hydraulic ram . Use a mandrel inside the tube rail with the hydraulic ram if the radius is less than 3 feet. Do not mit er and cut, weld, or heat curve. Do not kink t ubes in the radius section. Drop weight tear testing in accordance with ASTM E436 on curved tube sections is not required. Bend rail sections before galvanizing. Provide at least 24 inches between compound curves . Provide tubes for curved sections with a wall thickness of at least ⅜ inch. Mill splice pieces to fit . Saw or mill the ends of tube sections . Cut ends true, smooth, and free of burrs or ragged edges . Cap open ends of the rail . Erect tube r ailing sections with the longitudinal seam weld facing downward. Provide a continuous railing system, splicing each joint as shown on the plans . Splice rail tube sections in the same panel. Before casting concrete, set anchor studs for railing posts using a template in accordance with subsection 706.03.L and as shown on the plans for spacing railing posts . Tighten nuts for the anchor studs and fasteners to a snug, tight condition in accordance with subsection
707.03 E.6.c .
B.Concrete Railings
1.Parapet Railings. Cast parapet railings in accordance with section 706. Provide smooth and tight -fitting forms . Rigidly hold forms to the line and grade shown on the plans and remove without damaging the concrete. Construct moldings, panel work, and bevel strips with mitered joints . Provide true, sharp, clean-cut, finished corners, free of cracks, spalls, and other defects . Provide a rubbed surface finish to exposed vertical and top surfaces in accordance with subsection 706.03.R.2.
2.Bridge Barrier Railings . Construct bridge barrier railings in accordance with section 706 and section 804.
3.Bridge Barrier Railing Replacement . Construct replacement barrier railings to the limits shown on the plans in accordance with subsection
711.03 B.2 . Adhesive anchor barrier railing reinforcement into existing
concrete in accordance with section 712.
C.Timber and Lumber Railings . Construct timber and lumber railing portions in accordance with section 709.
D.Removal of Aluminum Railing . Remove alumi num tube and posts on parapet railings . Leave anchor bolts in place. MDOT Standard Specifications for Construction Section 711 7-117 E. Bridge Railing, Thrie Beam Retrofit . Drill holes or slots in thrie beam elements . Do not flame cut beam elements. Core drill holes in existing concrete. Determine the location of existing reinforcement with a pachometer, or other nondestructive method, to avoid cutting existing reinforcement while coring. Avoid spalling concrete during drilling. If spalling occurs, remove loose concrete before installing bolts . Remove concrete fragments from the work area. Do not patch spalled areas. Install nuts on bolts and studs at 5-inch slots in thrie beam expansion sections and finger -tighten. Fully engage nuts and bolts with at least one bolt thread extending beyond nuts . Upset the first thread outside the nut with a center punch or a cold chisel to prevent loosening. Tighten lag screws in 5 -inch slots so washers fully contact beam elements, but do not impede movement due to expansion. If thrie beam elements cover existing structure name plates, install new name plates near the end of railings on the fascia side. Attach name plates as shown on the plans, except make attachments with ⅜-inch- diameter expansion anchored bolts.
F.Permanent Barrier Reflective Marker . Use barrier markers the same color as reflector marking colors required for the location. Install markers using the manufacturer ’s recommended adhesive and in accordance with the manufacturer ’s recommendations. Remove dirt or curing compound from bridge barrier railings or concrete barriers before installing barrier markers . Install barrier markers every 50 feet, placing the first marker within 50 feet of the end of the bridge barrier railing or concrete barrier . For bridge barrier railings or concrete barriers less than 50 feet long, place a second marker within 3 feet of the opposite end. Install the markers with the top of the marker 28 inches above the roadway surface.
G.Bridge Railing, Aesthetic . Construct aesthetic parapet or barrier railings in accordance with 711.03.B . Adjust the width of the parapet or barrier according to the details shown on the plans to accommodate form liners to accomplish texturing on the back of the bridge barrier railings and parapet railings. Attach the guardrail to the bridge barrier railing with longer anchor bolts if required to accommodate the additional barrier thickness . Eliminate aesthetic texturing in guardrail anchorage area or provide a galvanized 14- by 26- by ⅜ -inch plate if aesthetic textured concrete falls within guardrail anchorage limits. MDOT Standard Specifications for Construction Section 711 7-118 711.04. Measurement and Payment Pay Item Pay Unit Bridge Railing, Aesthetic Parapet Tube ..................................................... Foot Bridg e Railing, Aesthetic Parapet Tube, High Performance ....................... Foot Bridge Railing, Aesthetic Parapet Tube, Det __ ......................................... Foot Bridge Railing, Aesthetic Parapet Tube, Det __, High Performance ................................................................................... Foot Bridge Railing, Thrie Beam Retrofit ........................................................... Foot Bridge Railing, __ Tube ............................................................................. Foot Bridge Barrier Railing, Type __ .................................................................. Foot Bridge Barrier Railing, Type __, High Performance ................................... Foot Bridge Barrier Railing, Type __, Replacement ........................................... Foot Bridge Barrier Railing, Type __, Replacement, High Performance .................................................................................. Foot Bridge Barrier Railing, Aesthetic, Type __, Det __ ..................................... Foot Bridge Barrier Railing, Aesthetic, Type __, Det __, High Performance ................................................................................... Foot Bridge Barrier Railing, Aesthetic, Type __, Det __, Replacement ........................................................................................... Foot Bridge Barrier Railing, Aesthetic, Type __, Det __, Replacement, High Performance ............................................................ Foot Pipe Railing, (material) .............................................................................. Foot Reflective Marker, Permanent Barrier ....................................................... Each
A.General . The Engineer will measure, and the Department will pay for , reinforcing steel and aesthetic texturing as specified in subsection 706.04. The Engineer will measure, and the Department will pay for , adhesive anchoring of steel reinforcement as specified in subsection 712.04. The Engineer will measure, and the Department will pay for , furnishing light standard anchor bolt assemblies as specified in subsection 819 .04. The High Performance pay items denote railings that are high performance.
B.Bridge Railing, Aesthetic Parapet Tube. The Engineer will measure the Bridge Railing, Aesthetic Parapet Tube pay items based on plan quantities . The unit price for the Bridge Railing, Aesthetic Parapet Tube pay items includes the cost of the following:
1.Providing and placing concrete parapets and end walls;
2.Providing and placing tube railing;
3.Constructing joints ;
4.Providing and placing anchor bolts or insert sleeves;
5.Forming, finishing, curing , and protecting the concrete; and MDOT Standard Specifications for Construction Section 711 7-119 6. Placing light standard anchor bolt assemblies. Bridge Railing , Aesthetic Parapet Tube of the detail specified includes the cost of the concrete that fills form liners and the concrete necessary to construct the railing to the shape shown on the plans .
C.Bridge Railing, Thrie Beam Retrofit . The Engineer will measure Bridge Railing, Thrie Beam Retrofit based on plan quantities . The unit price for Bridge Railing, Thrie Beam Retrofit include s the cost of attaching guardrail anchorages to bridge railing end posts and providing and installing new structure name plates . The Department will pay for reflectorized washers separately.
D.Bridge Railing Tubes . The Engineer will measure Bridge Railing, _ _ Tube based on plan quantities . The unit price for Bridge Railing, __ Tube includes the cost of the following:
1.Providing and placing tube railing;
2.Providing and placing anchor bolts or insert sleeves; and
3.Placing light standard anchor bolt assemblies . The Department will pay for concrete end walls and concrete brush blocks separately as specified in subsection 706.04.
E.Bridge Barrier Railing . The Engineer will measure the Bridge Barrier Railing pay items of the specified type based on plan quantities . The unit price for the Bridge Barrier Railing pay items of the specified type includes the cost of the following:
1.Providing and placing concrete;
2.Constructing joints;
3.Forming, finishing, curing and protecting the concrete; and
4.Placing light standard anchor bolt assemblies. The Aesthetic pay items include the cost of the concrete that fills form liners and concrete necessary to construct the railing to the shape shown on the plans . The Replacement pay items include adjustments in construction operations necessary to construct railings on existing concrete.
F.Pipe Railing. The Engineer will measure the length of Bridge Railing, Pipe based on plan quantities.
G.Reflective Marker, Permanent Barrier . The unit price for Reflective Marker, Permanent Barrier includes the cost of providing and installing the marker.
Source: Michigan Standard Specifications for Construction, 2020 Edition. Pages 479–483 of 1,146.