7-82 backside of the extruded plank panels that provide a groove acc ommodating a post clip bolt and assembly. Post clips shall be 356-T6 aluminum conforming t o the requirements of ASTM B 108. The post clip bolt material for overhead signing s hall be stainless steel conforming to the requirements of ASTM A 193/A 193M, AISI Type 304, Grade B8. The post clip bolt nut shall be stainless steel material con-formin g to the requirements of ASTM A 194/A 194M, AISI, Type 303, Grade 8F and of the locknut type with nylon inserts. Flat washers of these assemblies shall be stainless steel material c onforming to the requirements of ASTM A 276, Type 302. 719.074 Post Clip Hardware For Roadside Signing Signs mounted on other than overhead locations may be mounted using aluminum hardware. The aluminum post clips shall be 356T-6 aluminum conforming to the requirements of ASTM B 108. The post clip bolts, washers and nuts shall conform to the requirements of al uminum alloy 2024-T-4 (bolts and washers) and alloy 6061-T6 or 6262-T9 (lock nuts). 719.075 Roadside Signing Aluminum signs mounted on U-channel p osts shall be fastened with 5/16 by 1½ inch stainless steel bolts, washers, and self-locking ty pe nuts. The bolts shall conform to the requirements of ASTM F 593. A washe r, either a white nylon or neoprene or stainless steel ASTM F 593 shall be used between th e head of the bolt and the face of the sign. Plywood signs mounted on U-channel posts shall be fastened with 5/16 by 2½ inch stainless steel cap screws and hex nuts conforming to ASTM F 59 3, and a washer either white nylon or neoprene or stainless steel ASTM F 593 shall be used between the head of the bolt and the face of the sign. Delineator assembly hardware shall consist of ¼ by 2¼ inch stai nless steel bolts, washers, and self-locking type nuts. The bolt assembly shall c onform to the requirements of ASTM F 593. SECTION 720 - STRUCTURAL SUPPORTS FOR HIGHWAY SIGNS, LUMINAIRES AND TRAFFIC SIGNALS
720.01 Aluminum Supports Extrusions for aluminum supports sha ll conform to
ASTM B 221 or ASTM B 429, Alloy 6061-T6 or 6063-T6. Castings f or use with aluminum supports shall conform to ASTM B 26or B 108, Alloy 356.0-T6, ex cept that castings for parts having a non-structural application, such as pole caps or bolt covers, may be temper F. The T6 tempers specified for Alloys 6063 and 356.0 shall be obt ained by the proper heat treatment of the assemblies after all welding for the base and if required, for the handhole reinforcement has been completed. No welding will be allowed o n the shaft other than as required for the attachment of the shoe base, handhole reinforc ement and bracket arm. All welding for aluminum shall conform to the current edition of AW S Structural Welding Code - Aluminum D1.2 (AWS D1.2). 7-83 All welds shall be inspected and conform with AWS D1.2, Clause 5, Inspection. 100% of welds shall be visually examined (VT). In addition to V T, 10% of all partial joint penetration (PJP) and fillet welds shall be dye penetrant teste d (PT); locations to be PT examined will be designated by the QAI. 25% of complete joint p enetration (CJP) welds shall be ultrasonic tested (UT) or PT based on the thinner mate rial in the welded joint; joints with thinner material thicknesses less than 0.25 inch shall be PT examined and joints with thinner material thickness equal or greater than 0.25 inch shal l be UT examined. Locations to be UT examined will be designated by the QAI. Extent of test ing shall conform with AWS D1.2, Clause 5. The exterior of all parts shall have a satin brushed or satin etched finish. The assemblies shall be free of bulges, dents, and cracks and on ex ternal surfaces, discoloration and scratches. The presence of any of these defects or any oth er imperfection detrimental to strength or appearance may be cause for rejection by the Reside nt. All assemblies shall be tire wrapped for protection during shipment, storage, and handl ing. All ends of shafts open to the weather shall be fitted with a cast-aluminum or formed aluminum cap secured in place with set screws. All assemblies shall be permanently marked on the edge of the base plate or flange, indicating alloy and temper of ba se plate/flange and shaft, as well as the diameter and wall thickness of the shaft.
a.Light Standards, Mast Arm Poles, Strain Poles and Dual Purpo se Poles Shafts shall be round, tapered and seamless and shall be fabricated as a sin gle continuous unit without splices, except that shafts with a length of over 40 feet may b e fabricated with one splice at approximately mid-height and dual purpose poles may be fabricat ed with a splice immediately above the mast arm attachment. The minimum wall th ickness of the shaft shall be 0.188 inches. A hand hole of approximately 25 in² in area, reinforced to maintain the full design strength of the shaft, s hall be provided with the handho le center approximately 18 inches above the base. Provisions for internal grounding shall be incorporated in the handhole reinforcement. A hole, fitted with a rubber grommet, shall be provided in the shaft to match the wire-way of the bracket arm or mast arm, except th at strain poles shall be provided with a wire inlet as shown on the standard details. B ases shall be shoe type and shall be supplied with suitable covers for the anchor bolts. A nchor bolt covers shall be securely fastened to the base by means of one or more stainless steel Phillips or hex head screws with a minimum size of ¼ inch. Bases shall be welded to the shaft with both an internal and external continuous fillet weld. The use of sleev e type bases or other bases not requiring welding of the shaft t o the base and the use of reinf orcing sleeves will not be allowed. Dual-purpose poles shall be provi ded with a pull wire for the l uminaire.
b.Colonial Light Standards Sha fts shall be round, tapered and seamless and shall be fabricated as a single continuous unit without splices. The mi nimum wall thickness shall be 7-84 0.125 inches and the minimum diameter at the base shall be 5 in ches. The length of the shaft plus the base shall be 14¼ feet, with a 4 inch long by 3 inch OD straight section at the top to accept the pole top luminaire. The entire assembly of p ole and base shall be black anodized. Bases shall be handhole type with a handhole of appr oximately 25 in² in area and equipped with an approved locking device on the handhole cover. The bases shall have internal flanges capable of accepting four ¾ inch anchor bolts, equally spaced on a 10 inch diameter bolt circle. The bases shall be welded to the shaft w ith both an internal and an external continuous fillet weld.
c.Pedestal Poles Shafts shall be round, tapered and seamless and shall be fabricated as a single continuous unit without splices. The minimum outside di ameter at the base shall be 6 inches and the minimum wall thickness shall be ⅛ inch. The len gth of the pole plus the base shall be 10 feet, except that the length of poles supporting on ly pedestrian heads shall be 8 feet. Bases shall be transformer type with suitable covers for the anchor bolts. The bases shall be welded to the shaft wit h an external and an internal f illet weld.
d.Bridge, Cantilever and Butterfly Type Sign Support Structure s The configuration of the foundations, bases, shafts, and trusses shall be of the Con tractor's design, as approved by the Engineer, and shall use only material as specified above. Sleeve type bases or other bases not requiring welding to the shaft and the use of reinfor cing sleeves will not be allowed.
720.02 Aluminum Mast Arm and Bracket Arm Mast arms and bracke t arms shall be
of the same materials as the matching pole and have a similar f inish. Member cross sections shall be either round or elliptical and have a minimum wall thi ckness of ⅛ inch. Internal diameters, bends, joints, and attachments shall permit internal wiring in the upper member of the arms. Fixtures for attaching the arms to the poles shal l be either castings or extrusions, sized to meet the design requirements, and shall be designed to prevent rotation of the arms about the poles. Any mechanical means used to prev ent rotation shall completely penetrate both the fixture and the shaft and the use of set screws will not be allowed. All welding for aluminum shall conform to the current edition of AWS Structural Welding Code - Aluminum D1.2 (AWS D1.2). All welds shall be inspected and conform with AWS D1.2, Clause 5, Inspection. 100% of welds shall be visually examined (VT). In addition to V T, 10% of all partial joint penetration (PJP) and fillet welds shall be dye penetrant teste d (PT); locations to be PT examined will be designated by the QAI. 25% of complete joint p enetration (CJP) welds shall be ultrasonic tested (UT) or PT based on the thinner mate rial in the welded joint; joints with thinner material thicknesses less than 0.25 inch shall be PT examined and joints with thinner material thickness equal or greater than 0.25 inch shal l be UT examined. Locations to be UT examined will be designated by the QAI. Extent of test ing shall conform with AWS D1.2, Clause 5.
a.Mast Arms for Signals Mast arms shall be of the tapered tub e truss type design, consisting of an upper and a lower member with vertical struts, welded to form an integral unit or single member tapered arm. Mast arms shall be equipped with sturdy signal hangers 7-85 and/or appropriate tenons for m ounting the signal heads and sha ll have weatherproof wire inlets located close to the suspended signal heads.
b.Bracket Arms for Luminaires Bracket arms shall be of the si ngle member or truss type. Single member type bracket arms shall be of the tapered upsweep design. Truss type bracket arms shall be of a tapered tube design, consisting of a n upper and a lower member and a single vertical strut, wel ded to form an integral unit. Arms shall be equipped with an appropriate tenon for the attachment of the luminaire.
720.03 Steel Supports Tapered shafts for steel supports shall conform to ASTM A 595,
Grade A or approved equal. Strai ght shafts for steel supports shall conform to ASTM A 53, Grade B, ASTM A 500, Grade A and B, or an approved equal. Base plates and flanges shall be fabricated of steel plate conforming to ASTM A 709, Grade 36 or 50 and sized to transmit the full design load of the shaft. Steel shapes shall conform to the requirements of ASTM A 992. Flange chord splice plates and base plates are con sidered main load carrying members and shall comply with the requirements of Section 713.0 1 - Structural Steel. All work shall conform to the applicable provisions of Section 504 - Structural Steel. The interior and exterior of all support structure components s hall be hot-dip galvanized in conformance with AASHTO M 111. Chord flange splice fastener assemblies shall conform to ASTM A 325, Type 1, and galvanized in accordance with AASHTO M 232 (ASTM A 153 or B 695 , Class 50, Type 1). Other fastener assemblies shall be as specified in Section 719. 07, or as approved by the Engineer. All ends of shafts open to the weather shall be fitted with an appropriate cast aluminum or galvanized cast iron cap secured in place with stai nless steel set screws conforming to the requirements of ASTM F 593. All assemblies of each structure shall be permanently marked o n the edge of the base plate or flange indicating st eel specification, type and grade of base plate/flange and shaft, as well as the diameter and wall thickness of the shaft.
a.Light Standards, Mast Arm Poles, Strain Poles and Dual Purpo se Poles Shafts shall be round, unless otherwise specified in the contract plans, and either tapered or of uniform cross section and shall be fabricated as a single continuous un it without splices, except that shafts with length over 40 feet may be fabricated with one spli ce at approximately mid- height and dual purpose poles may be fabricated with a splice i mmediately above the mast arm attachment. The minimum wall thickness of the shafts shall be number 7 gauge. A hand hole of approximately 25 in² i n area, reinforced to mainta in the full design strength of the shaft, shall be provided with the hand hole center approxim ately 18 inches above the base plate. Provisions for i nternal grounding shall be provide d in a location accessible through the hand hole. A hole, fitted with a rubber grommet, s hall be provided in the shaft to match the wire-way of the bracket arm or mast arm, except th at strain poles shall be 7-86 provided with a wire inlet as shown on the standard details. On dual-purpose poles, a pull wire shall be provided for the luminaire.
b.Pedestal Poles Shafts shall be 4 inch nominal ID, schedule 40 pipe without splices. The length of the pole plus the base shall be 10 feet, except t hat the length of poles supporting only pedestrian heads shall be 8 feet.
c.Bridges, Cantilever, and Butterfly Type Sign Support Structu res The configuration of the foundations, bases, shafts, and trusses shall be of the Con tractor's design as approved by the Resident and shall use only material specified above.
720.04 Steel Mast Arm and Bracket Arm Material for mast arms a nd bracket arms shall
be as specified in Section 720.03. Int ernal diameters, bents, joints, and attachments shall permit internal wiring in the upper member of the arms. Arms s hall be hot dipped galvanized, both inside and outside, in conformance with AASHTO M 111. All work shall conform to the applicable provisions of Section 504 - Structura l Steel.
a.Mast Arms for Signals Mast arms may be of the single member or the truss type. Single member type mast arms shall be a single, straight or tap ered, round member and may incorporate a maximum of 2 telescopic splices. Truss type mast arms shall be of a tapered design consisting of an upper and a lower member connected by v ertical struts welded to form an integral unit. Mast arms shall be equipped with sturdy signal hangers and/or appropriate tenons for mounting the signal heads and shall have weatherproof wire inlets located close to the suspended signal heads.
b.Bracket Arms for Luminaires Bracket arms may be of the sing le member or the truss type. Single member type bracket arms shall be of the tapered u psweep design. Truss type bracket arms shall be of a tapered design consisting of an uppe r and lower member connected by a single vertical s trut, welded to form an integra l unit. Bracket arms shall be equipped with an appropriate tenon f or the attachment of the lu minaire.
720.05 High Mast Light Standard High mast light standards shal l have a cross section
that is either round or polygonal with not less than 12 sides, and shall have a uniform taper from the base to the top, except that an expanded base section may be used, if required, to accommodate the electrical and mechanical equipment. All work shall conform to the applicable provisions of Section 504 - Structural Steel. For unpainted high mast structures, material for the shaft, ba se and attachments shall conform to the requirements ASTM A 709 Grade 50W or ASTM A 595, Grade C. The base plate and reinforci ng components of high mast poles s hall be considered main load carrying members and shall comply with the requiremen ts of Table A, Section
713.01 Structural Steel. If applicable, the Contractor shall submit a proposed coating
specification for approval by the Fabrication Engineer.
Source: Maine Standard Specifications for Road and Bridge Construction, 2020 Edition. Pages 787–791 of 817.