11-16 Historical performance of the TMA will help determine the future use of the material by the
Department, even if the TMA has been approved . Poor performance of TMA at any site, wheth er or not related to a specific contract, may be grounds for non -acceptance of a product on any project under contract. 1165 -3 CONSTRUCTION METHODS Before use, furnish the Engineer detailed brochures, manufacturer’s specifications and other data that completely describes the performance criteria, installation and instructions for the TMA. Do not park TMAs against rigid objects ( i.e., bridge piers or portable concrete barrier) except as a temporary safety measure and i n no case for longer than 72 hours. Install the TMA on a truck that is fully operational, in good running order and in accordance with the manufacturer’s specifications. Use the appropriate lighting as described in Article 1101 -5 and delineation on the tr uck and TMAs as shown in the Roadway Standard Drawings . TMA trailer lighting systems shall be activated in the flash mode while deployed. Repair or replace within 24 hours any attenuator that becomes crushed or otherwise damaged so that it will perform its intended purpose. Suspend all construction activities until the attenuator is repaired or replaced. Provide safe control of traffic until the attenuator has been repaired or replaced using approved methods. 1165 -4 MEASUREMENT AND PAYMENT TMA will be measured and paid as the maximum number of TMAs acceptably placed and in use at any one time during the life of the project for all operations other than Moving and Mobile Operations. TMAs will be incidental to all moving and mobile operations. In the case of emergency situations, TMAs will not be paid when payment has already be en made for a stationary unit. Relocation of TMAs will be incidental to the measuremen t of the quantities of TMAs and no separate payment will be made. Payment will be made under: Pay Item Pay Unit TMA Each 1170 -1 DESCRIPTION Furnish, install, secure, maintain, remove and reset portable concrete barrier or water filled barrier . 1170 -2 MATERIALS Refer to Division 10. Item Section Anchor Bolts 1072 -4 Anchor Bolt Adhesive 1081 Concrete Barrier 854 Grout, Type 3 1003 Guardrail and Barrier Delineators 1088 -2 Portable Concrete Barrier 1090 Provide barrier and delineators t hat are listed on the NCDOT APL .
11-17 Historical performance of the barrier will help determine use of the material by the
Department, even if the barrier has been approved. Poor performance of the barrier at any site, whether or not related to a specific contract, may be grounds for non- acceptance of a product on any proj ect under contract. 1170 -3 CONSTRUCTION METHODS
A.General Place all types of barrier as shown in the plans and per manufacturer specifications . Use one type of barrier on any c ontinuous run of barrier within the project. Barrier shall be placed on an asphalt or concrete surface. Barrier should not be placed on cross slopes steeper than 6:1. Use barrier that avoid s trapping water in sags, vertical curves, areas of wedging and paving where super -elevations have been changed and other low spots. Provide adequate drainage behind the portable concrete barrier. Do not use any barrier units that are cracked, damaged, chipped or otherwise nonfunctional. Once temporary barrier is installed at any location and no work is performed behind the temporary barrier for a period longer than 2 months, remove or reset temporary barrier at no cost to the Department unless otherwise stated in the TMP, temporary barrie r is protecting a hazard, or as directed by the Engineer. Follow the manufacturer’s specifications and recommendations.
1.Portable Concrete Barrier Lift, place and reset portable concrete barrier units using a two -point pick up, or other acceptable method, which does not over -stress, damage or mar the surface of the roadway. Do not use connection points for lifting purposes. Use approved anchoring methods shown in Roadway Standard Drawings .
a.Anchoring Method for Asphalt Pavements Drill anchor holes normal to the surface of installation using a pneumatic drill with a depth indicator, unless another drilling method is allowed. Make sure that the diameter of the hole is in strict conformance with the Roadway Standard Drawing s or the manufacturer's reco mmendations. When directed, use a jig or fixture to ensure correct positioning of the holes and proper alignment during the drilling process. Adjust hole locations, as necessary, to avoid encountering reinforcing steel. Immediately after drilling, brush the holes with a stiff -bristled brush of a sufficient size to effectively remove dust from the sides of the hole, and blow all holes free of all dust and debris using oil free compressed air. Repeat this procedure until the hole is completely clean. Inspect each hole immediately before placement of the anchor. Rework any hole found to deviate from these requirements to ensure that an acceptable hole is achieved. Check each hole with a depth gauge to ensure proper embedment depth , if required . Satisfacto rily repair all spalled or damaged pavement. Once the barrier and anchors are removed, fill the holes with grout. These requirements may be waived if the bridge or roadway will no longer be used by traffic.
11-18 (b) Adhesive Anchoring Method for Concrete Surfaces
Comply with Subarticle 1170- 3(A)(1)(a). Mix adhesives in strict conformance with the manufacturer's instructions. Pour the mixed adhesive into the hole. Agitate or rotate anchors to ensure complete wetting and encapsulation. Insert the anchors to the spe cified depth. Completely fill the anchor hole with adhesive and remove any excess adhesive flush with the pavement. Do not disturb any anchors while the adhesive is hardening. Coat all anchors to be adhesively bonded with a debonding agent to ease remov al. Formulate the debonding agent such that it does not reduce the strength of the anchor system.
c.Through the Deck Anchoring Method Comply with Subarticle 1170- 3(A)(1)(a). Anchor barrier to bridge decks as shown in Road way Standard Drawings . Do not use this method on prestressed concrete bridge deck panels.
2.Water Filled Barrier Provide water filled barrier that acts as its own free standing, non -redirective end treatment or has an attached end treatment that completely captures the impacting vehicle without full penetration of the device. Water filled barriers shall not be placed such that fixed objects (including curbs) are within the lateral displacement area of the barrier according to the manufacturer’s specifications. Use environmentally safe anti -freezing agent in the water per manufacturer specifications and recover agent when the barrier is drained. Dispose of water and agent properly. Do not drain water filled barrier into or across an existing travel lane. Provide barrier units that are capable of being lifted and moved when filled if draining is not possible. For work zones on facilities with a posted speed limit greater than 45 mph, water filled barrier that meets Test Level III may be used only if there is adequate space for the lateral displacement of the barrier according to the manufacturer’s specifications. Alternatively, for work zones on facilities with a posted speed limit of 45 mph or less, provide water filled barrier that meets Test Lev el II or Test Level III. Water filled barrier at a 36 -inch height is preferred to limit sight distance impairment. If devices taller than 36 inches are used in this situation, transition down to 36 inches or shorter on the intersection approaches to provide proper sight distance.
B.Resetting Barrier Reset portable concrete barrier or water filled barrier as defined by the TMP .
C.Stockpiling Stockpile the portable concrete barrier when the barrier is not used on the project or it becomes necessary to stockpile units between 2 separate installations. Stockpile the barrier at a location off the project of your choosing, unless otherwise noted in the TMP , or to a location within the project limits , if provided.
11-19 (D) Barrier Delineators
Furnish barrier delineator for portable concrete and water filled barrier. T op mount delineator s for barrier throughout the project. Side mounted delineators may be used to supplement the top mounted delineators. Attach the delineator to the barrier using methods and spacing as shown in the Roadway Standard Drawings . The delineators consist of a reflector and base or casing. Position delineators perpendicular to the centerline of the road. Use yellow delineators in the median and on the left side of one -way ramps, l oops or other one -way facilities. Use white delineators on the right side of divided highways, ramps, loops and all other one - way or two -way facilities. In all cases, the color of the delineator shall supplement the color of the adjacent edgelines. 1170 -4 MEASUREMENT AND PAYMENT Portable Concrete Barrier ( ____) will be measured and paid as the maximum number of linear feet furnished, satisfactorily installed, accepted by the Engineer, maintained and removed , at any one time during the life of the project . Measurement will be made by counting the number of barrier units used and multiplying by the length of a unit. Water Filled Barrier will be measured and paid as the maxi mum number of linear feet furnished, satisfactorily installed, accepted by the Engineer, maintained and removed , at any one time during the life of the project . Measurement will be made by counting the number of barrier units used and multiplying by the l ength of a unit. Remove and Reset Portable Concrete Barrier ( ____) will be measured and paid as the number of linear feet of barrier moved from one location on the project to another location on the project. Measurement will be made by counting the number of barrier units moved during any one move and multiplying by the length of a unit. Where barrier units are moved more than once, each move will be measured separately. Whenever the Engineer directs the Contractor to move barrier units from an installed location to a stockpile either on or off the project and then back to another installed location, the complete move from the first installed location to the next installed location will be measured as 2 moves. Remove and Reset Water Filled Barrier will be measured and paid as the actual number of linear feet of barrier moved from one location on the project to another location on the project. Measurement will be made by counting the number of barrier units moved during any one move and multiplying by the length of a unit. Where barrier units are moved more than once, each move will be measured separately. Whenever the Engineer directs the Contractor to move barrier units from an installed location to a stockpile either on or off the project and then back to another installed location, the complete move from the first installed location to the next installed location will be measured as 2 moves . Provide barrier stockpile area s at no cost to the Department. B arrier delineators will be incidental to these pay items. Payment will be made under: Pay Item Pay Unit Portable Concrete Barrier Linear Foot Portable Concrete Barrier (Anchored ) Linear Foot Water Filled Barrier Linear Foot Remove and Reset Portable Concrete Barrier Linear Foot Remove and Reset Portable Concrete Barrier (Anchored ) Linear Foot Remove and Reset Water Filled Barrier Linear Foot
Source: North Carolina Standard Specifications for Roads and Structures, 2024 Edition. Pages 674–677 of 857.