5-109 culverts; the horizontal end reinforcing ribs for aluminum allo y structural plate pipe and pipe arches; the headwalls, wingwalls, toewalls, full metal inv ert and/or footing pads for metal box culverts; anchor bolts embedded in concrete; the rece iving channels for metal box culverts on concrete substructures; and all incidental items re quired to complete the work, including, but not limited to, the calibrated torque wrench for use by the Resident. Reinforced concrete headwalls and wingwalls are not included fo r payment under this item. Whenever the minimum cover material extends above the subgrade line, the removal of the material which is necessary to complete the work in accorda nce with the Plans will be measured and paid for as Common Excavation as provided in Secti on 203 - Excavation and Embankment. Payment will be made under: Pay Item P a y U n i t
509.11 Steel Structural Plate Pipe Lump Sum
509.12 Steel Structural Plate Pipe Arch Lump Sum 509.13 Steel Structural Plate Arch Lump Sum
509.141 Steel Structural Plate Box Culvert Lump Sum 509.18 Aluminum Alloy Structural Plate Pipe Lump Su m
509.19 Aluminum Alloy Structural Plate Pipe Arch Lump Sum
509.20 Aluminum Alloy Structural Plate Arch Lump Sum
509.411 Aluminum Structural Plate Box Culvert Lump Sum SECTION 510 - SPECIAL DETOURS
510.01 Description This work shall consist of the design, cons truction, maintenance in
good condition and removal of temporary structures and approach es required for the satisfactory maintenance of vehicular and pedestrian traffic. Easements or right-of-way for t he Special Detour will be furnis hed by the Department and will be shown on the Contract P lans. If the Contractor pro poses an alternative location for the Special Detour, and the alternative location is approve d by Department, that easement may only be acquired by the Department. All additiona l costs associated with the acquisition, including, but not limited to, obtaining easements , environmental mitigation, restoration and Department time, shall be borne by the Contract or.
510.02 Materials Materials used for the Special Detour structu re and approaches shall
conform to the detailed plans and specifications submitted by t he Contractor.
510.03 Vehicular and Pedestrian Traffic Not Separated The Spec ial Detour shall be
located as close as practicable to the new Work, or as shown on the Plans. 5-110 The Special Detour, including the temporary structure and appro aches, shall be designed and sealed by a Professional Engineer, licensed in accordance w ith the laws of the State of Maine. The Contractor shall submit the design computations and detailed plans of the temporary structure and approaches that will serve as the tempo rary detour to the Resident prior to beginning construction of the Special Detour. If the Department requires changes to Temporary Detour plans or computations, based on Contract requirements, then the Contractor shall implement t he changes at no additional cost to the Department. The Department shall have no obligation to review or comment on any design, construction, maintenance or removal of Temporary Detours. No review or comment by the Department, or any lack of review or comment by the Department, shall relieve the Contractor of its responsibility to properly design, construct, maintain in good condition, and remove Temporary Detours in accordance with the Contract, o r shall shift any responsibility to the Department. The Contractor shall be resp onsible for all damages resulting from the failure of temporary structures or approache s. The Special Detour shall not be opened to traffic until the Con tractor’s Professional Engineer inspects the temporary structure and provides the Depa rtment with a signed and sealed document certifying that the structure was built in acco rdance with the previously submitted sealed plans and design details of the structure and approaches. 510.031 Structure Design Temporary structures shall be designe d in accordance with the AASHTO Standard Specifica tions for Highway Bridges, 17th Edition, 2002, or the current edition of AASHTO LRFD B ridge Design Specifications, ex cept as noted herein, to meet live load requirements of HS25 for ASD and LFD, or HL-93, Maine Modified, for LRFD designs.
a.Deflections Primary structural members shall be designed so that deflection due to live load plus impact shall not exceed 1/300 of the span.
b.Fatigue Stresses Fatigue stresses for steel need not be con sidered if the steel is judged by the Contractor’s Professional Engineer to be in sound struct ural condition.
c.Bridge Railing Loads Bridge railing shall be designed in a ccordance with AASHTO Standard Specifications, 17th Edition, 2002 or the current edition of AASHTO LRFD Bridge Specifications, except that the Standard Specification design l oad "P", specified as 10 kips, may be decreased to 5 kips. However, allowable design stresses for material used in bridge rails and posts shall not be increased above those allowed by A ASHTO Standard Specifications.
d.Waterway Opening The minimum waterway opening of the tempo rary structure shall be designed to pass the Design Dis charge indicated in the Contr act Specifications, without any overtopping of the roadway. 5-111
e.Foundations Temporary foundations, embankment foundations and earth retaining structures shall be designed in accordance with the AASHTO Stan dard Specifications, 17th Edition, or the current edition of the AASHTO LRFD Bridge Desig n Specifications and AASHTO LFRD Bridge Construction Specifications, except as noted herein. The Contractor is responsible for determining the ultimate load car rying capacity of the foundation materials and foundation elements for the Special De tour. The determination of the ultimate load carrying capacity may require characterizatio n of the subsurface conditions by the Contractor by means of subsurface investigation. The applied loads on foundations shall consider both dead and l ive loads and all other applicable loads and forces. The Contractor is responsible for choosing an applicable factor of safety for foundations on soil and rock and an appropriate d esign load group. The factor of safety and maximum applied load, or LRFD factored applied lo ads and factored geotechnical resistances, used for each foundation design shall be clearly stated on the submitted calculations. 510.032 Geometric and Approach Design The geometric design of t he Special Detour, except as otherwise shown on the Plans or as noted herein, shal l be designed in accordance with the current AASHTO Specification "A Policy on Geometric De sign of Highways and Streets".
a.Horizontal Alignment Horizont al curve radius shall not be less than 200 feet at the centerline of roadway, except as otherwise shown on the Plans. Roadway width as indicated in the Contract shall be the minimum clear travel width between faces of bridge curbs, bridge rails or approach rails, whichever is less. The approach roadway shall have 2 feet wide shoulders, minimum, to the roadway berms, where guardrail is not required, in addition to the roadway width ind icated in the Contract. The roadway width shall be increased on curved portions of the Special Detour to account for the off tracking char acteristics of a WB-62 vehicle in accordance with the AASHTO publication ‘A Policy On Geo metric Design of Highways an d Streets’ (the Green Book), chapter 3 table entitled Design Widths of Pavements for Turning Roadways.”
b.Vertical Alignment Grades shall not exceed 10 percent and any change in grade shall accommodate all legal highway vehicle components or attached lo ads.
c.Approach Road Guardrail The Special Detour approaches shal l have guardrail where side slopes are steeper than t hree horizontal to one vertical. Approach guardrail shall be attached to the bridge rail in a manner that develops the appro ach guardrail in tension. Approach guardrail shall consist of Type 3 guardrail or an appr oved equal, unless other rail or barriers are specified. The termination of approach guardrail and the end treatment of the rail shall be in accordance with the current AASHTO Roadside Design Guide. 5-112
d.Approach embankments The earth material used for approach embankments shall have sufficient strength under the placement method specified i n the Contractor’s plans to maintain stability throughout the duration of the Special Detou r.
e.Approach Road Base Drainage The approach road base structu re shall consist of a 1 foot thick layer, minimum, of aggregate subbase course gravel, Type D or E. This layer shall be designed to support legal loads during the use of the detour. Drainage shall be designed to drain the approach area.
f.Approach Road Surface The a pproach road surface, including the shoulders, shall be paved with a 3 inch, minimum, thickness hot bituminous pavement layer, except when specified to be a gravel surface. When a gravel surface is spe cified, it shall consist of an approved gravel.
g.Design Speed The design speed of the Special Detour shall be not less than the construction area posted speed limit, or the advisory speed lim it, as applicable, unless otherwise indicated in the Contract.
510.04 Pedestrian Traffic Only The provisions of Section 510. 03 - Vehicular and
Pedestrian Traffic Not Separated, shall apply to this Section w ith the following modifications:
a.Structures shall be designed for a live load of 85 lb/ft². b. The Special Detour shall have a minimum clear width of 5 fe et or as specified in the Contract.
c.Vertical alignment and ramps shall be ADA compliant. d. Deflections due to live load shall not exceed 1/300 of the span.
510.05 Vehicular and Pedestrian Traffic Separated The provisio ns of both Section
510.03 Vehicular and Pedestrian Traffic Not Separated, and Se ction 510.04- Pedestrian
Traffic Only, shall apply to thi s Section. If vehicles and ped estrians are carried on the same structure, each shall have its own lane as specified. The pede strian lane shall be protected from vehicular traffic by being a t least 9 inches above the roa dway surface or suitably protected by means of an adequate curb at least 9 inches in hei ght above the roadway surface. No bridge rail will be required between vehicle traff ic and pedestrian traffic, unless otherwise specified, but shall be located at the exterior side of the sidewalk.
510.06 Special Detour Construction T he Special Detour, includin g temporary structures
and approaches, shall be constructed in accordance with the pla ns submitted by the Contractor. Barricades, warning s igns, lights and other traffi c control devices shall be provided in accordance with the Contract and the approved Traff ic Control Plan. The temporary structure’s deck and floor members shall be faste ned or anchored so that all contact surfaces with adjacent supporting members bear cont inuously. If timber plank decking is used, it shall be secured into timber nailer strips with screw-type nails, or securely fastened by an alternate method that will prevent the decking from loosening.
Source: Maine Standard Specifications for Road and Bridge Construction, 2020 Edition. Pages 401–404 of 817.