551Payment will be made under: ————————————————————————————— ————————Pay Item Pay Unit————————————————————————————— ————————Coating of new metal on structures (B or Str. No.) Lump sum Prepare and spot coat existing structure (B or Str. No. and type) Square foot Zone coating of existing structure (B or Str. No. and type) Lump sum Prepare and overcoat existing structure (B or Str. No. and type) Lump sum Recoat existing structure (B or Str. No. and type) Lump sum Environmental protection and health and safety (B or Str. No.) Lump sum Disposal of material (B or Str. No. and type) Lump sum————————————————————————————— ———————— SECTION 412—WIDENING, REP AIRING, AND RECONSTRUCTING EXISTING STRUCTURES
412.01 Description
This work shall consist of widening, repairing, or reconstructing existing concrete structures in accor - dance with the lines, dimensions, plan details, and these specifications or as directed by the Engineer.
412.02 Materials
a.Epoxy and mineral fillers shall conform to Section 243. Epoxy for epoxy mortar shall be Type EP-5. Epoxy used for crack repair shall be Type EP-4 or EP-5, low viscosity. Epoxy for epoxy injec - tion shall be Type EP-4 L V Modified and shall have a viscosity of 5 poises or less at 75 degrees F .
b.Hydraulic cement concrete shall conform to Section 217, except that the coarse aggregate shall be size No. 7, No. 8, or No. 78 for depths and steel clearances less than 2 inches and shall be size No. 57, No. 7, No. 8, or No. 78 for depths more than 2 inches. A Department approved accelerator from the Materials Division’ s Approved Products List 2 may be permitted by the Engineer when justified by work restrictions, traffic limitations, or closure timeframes. Concrete specified as High Early Strength (HES) shall be either a high early strength Class A4 ready mixed concrete, or an approved hydraulic cement concrete patching material from the Materials Division’ s Approved Products List 31. The type of material to be used shall be approved by the Engineer prior to the beginning of the work at each location. When a HES patching material is approved for use at the specific location by the Engineer, the patching material volume may be extended with coarse aggregate in accordance with the manufac - turer’ s recommendations. Surface preparation, placement, and curing of the patching material shall be in accordance with the manufacturer’ s instructions and this specification. Patching materials must obtain a minimum compressive strength of 2500 psi when tested in accor - dance with ASTM C1074 prior to permitting vehicular traffic on patched areas. The Contractor shall make trial batches under the observation of the Engineer for each type of patching material used during this project to verify that concrete of the required workability and consistency 412.02 552is obtained within the specified water content. Concrete test cylinders shall be made from the trial batches to verify the compressive strength obtained within the time intervals designated by the Engineer is acceptable. Self-consolidating concrete shall conform to Section 217.
c.Reinforcing steel shall conform to Section 406. Deformed reinforcing bars shall conform to ASTM A615 Grade 60, ASTM A1035/A1035M, or ASTM A955/A955M, as specified on the plans or as directed by the Engineer.
d.Accelerators shall conform to Section 215, be noncorrosive, and must be approved by the Engineer prior to use.
e.Materials for shotcrete shall be either a prepackaged material from the Materials Divi- sion’ s Approved Products List 33 or delivered by a transit mixer and conform to the following:
1.Portland and blended cements shall conform to Section 214.
2.Fly ash, slag, and silica fume shall conform to Section 215.
3.Water shall conform to Section 216.
4.Air-entraining admixtures shall conform to Section 215.
5.High-range and regular water reducers shall conform to Section 215.
6.Accelerators shall conform to Section 215 but may be used only if approved by the Engineer. If approved, they shall be added at the nozzle.
7.Fine aggregates shall conform to Section 202 for Grading A. Coarse aggregates shall be No. 8 aggregate conforming to Section 203.
8.Steel fibers and Synthetic fibers shall be from the Materials Division’ s Approved Products List 35.
f.Welded wire fabric shall conform to Section 223 and shall be galvanized or stainless steel.
g.Expansion bolts shall be selected from the Materials Division’ s Approved Products List 29 and shall conform to these specifications.
h.Carbon Fiber Mesh Materials shall conform to Section 250.
i.Embedded Galvanic Anodes shall conform to Section 251.
j.Gravity fill polymer crack sealers shall conform to Section 252.
k.Concrete surface color coating shall be from the VDOT Materials Division’ s Approved Products List 30.
l.High Strength Grout shall conform to Section 218.412.02 553(m) Fiber Reinforced Polymer Wraps shall meet the requirements of the specific conditions of the project as determined by the Engineer. Material requirements for acceptable systems will be includ - ed in the Contract.
n.Anchor Bolts shall conform to Section 226.
412.03 Procedures
Repairing concrete structures shall consist of removing deteriorated material, thoroughly cleaning exposed concrete surfaces and reinforcing steel, and replacing reinforcing steel where required, and replacing removed unsound or unnecessary concrete with new material. Prior to placement of new material, cleaning shall be performed by abrasive blast cleaning, or other means approved by the Engineer to remove unsound concrete, rust, oil, and other foreign materials detrimental to achieving a bond. The areas and depths of repairs shall be as directed by the Engineer. Dimensions of existing structures shown on the plans are approximate, and those that are pertinent to the construction of the new portion shall be verified in the field by the Contractor. Where details of new portions of the structure shown on the plans are not adaptable to the shape of the existing structure, the Contractor may make practical modifications during construction with the Engineer’ s approval provided neither the existing nor the new portions are impaired in structural strength. Before proceeding with any work within or adjacent to the existing structures, the Contractor shall become familiar with existing conditions. During construction operations, it shall be the Contractor’ s responsibility to maintain the integrity of the existing structures where the existing structures are mod - ified to accommodate new construction, and to protect from damage those portions of the structures which are to remain.
a.Preparation of Concrete Patches When reinforcing bars are exposed, including epoxy coated or galvanized bars, the exposed length shall be cleaned by abrasive blast cleaning. Any epoxy coating that is well-bonded to the bars after abrasive blast cleaning (i.e., unable to be pried off when being cut and pried with stout knife blade at several locations) does not have to be removed and bare areas do not have to be repaired. Care shall be taken to prevent striking reinforcing bars with hammer points. Reinforcing steel that has lost 1/4 or more of its original cross-sectional area shall be lapped with new bars of the same material type, size, and shape, or as specified on the Plans. New bars shall lap existing bars a length of 30 diameters on each side of the damaged portion if a sufficient length of the existing bar is exposed. Otherwise, new bars shall be mechanically connected in accordance with Section 406 except when the new bars specified on the Plans are a different material type, then the splice sleeves shall be the same material as the new bars and not coated when spliced to existing epoxy coated reinforcing bars. New bars may be welded with a 6-inch arc-welded lap on each side of the damaged portion with a single-flare V-groove weld in accordance with Section 407 if specified on the Plans or authorized by the Engineer in writing. The Contractor shall support unsupported areas with forms or falsework. The Contractor shall remove and dispose of excess material and debris resulting from repairs in an approved disposal area in accordance with Section 106.04. Wherever new concrete is scheduled to be placed against existing concrete, the two concrete masses shall be connected as indicated in the Plans. Where no plan details are provided, dowels at least 412.03 5543/4 inch in diameter shall be placed at no more than 2 feet 6 inches center to center over the entire joining surface and 6 to 12 inches from the edge. Dowels shall be placed perpendicular to the surface of existing concrete by drilling and grouting and shall project into both new concrete a nd existing concrete to a depth as great as the thickness of the concrete will allow but need not project more than 9 inches into either surface. The Contractor will not be required to install dowels if other acceptable means for connecting new concrete to existing are available. Acceptable alternative methods include lapping of reinforcing steel protruding from the existing concrete surface or use of approved mechanical splices to provide continuity between new and existing reinforcing steel. For footings and neat work of substructures where joining planes are vertical, 3/4-inch headed expansion bolts shall be used instead of dowels. Bolts shall project at least 9 inches into new concrete and shall extend sufficiently far into existing concrete to develop their rated pullout strength but not less than 6 inches. The Contractor shall exercise care so that existing reinforcing steel is not damaged when drilling holes for expansion bolts. Where necessary to prevent featheredges, existing concrete shall be removed to ensure a thickness for new concrete of at least 6 inches. All of the concrete within a span lane that is to be removed shall be removed before recasting any concrete within that span lane, unless otherwise approved by the Engineer. No concrete repairs, including removal and recasting of superstructure and substructure concrete, shall be performed within a span lane that is under traffic unless approved by the Engineer. For full depth deck repair or expansion joint elimination or reconstruction that is not protected by concrete traffic barrier, the work shall be limited to that amount which can be performed within the duration of the scheduled lane closure unless alternate means of temporarily protecting the opening are provided. Any method for allowing traffic to ride over a temporary construction opening shall be designed to sustain traffic loading by the Contractor, and Working Drawings conforming to Section
105.10 shall be submitted to the Engineer for approval prior to use.
Where steel plates are provided to protect damaged or patched areas from traffic, the steel plate shall be of sufficient size, thickness, and strength to temporarily support traffic. Additionally, temporary anchorages between the steel plate and deck shall be adequate to prevent movement of the plate under traffic. The Contractor shall provide appropriate work platforms, scaffolds, under bridge access vehicles, and other equipment that is required to obtain access to areas of work. The Engineer shall be provided access to work areas to determine the extent of repairs and to inspect the work. The cost of access equipment and materials shall be included in the price bid for the appropriate items.
1.Remove Existing Concrete and Replace with New The Contractor shall sound the surface of the concrete element to be repaired in accordance with ASTM D4580 in the presence of the Engineer. The Contractor shall then outline areas to be repaired with paint or other marker in rectangular patterns. Prior to performing repairs, ob - tain verification from the Engineer that marked areas are the appropriate areas requiring repair. Sawcut edges of area to be repaired to a depth of at least 1 inch or to a depth that shall clear the top of the reinforcing steel.412.03 555Remove loose and unsound materials by the use of hand tools or pneumatic hammers weighing a nominal 35 pounds or less. Hammer weight applies to the weight of the pneumatic hammer alone. Pneumatic hammers shall be worked at an angle of 45 to 60 degrees to the plane of the concrete surface being removed. Whenever existing reinforcing bars are exposed, concrete shall be removed to a depth of no less than one inch beyond the reinforcing bars. Existing concrete shall be removed as shown on the plan details or as directed by the Engineer, to horizontal and vertical planes only, and to sound concrete, taking care not to damage any existing reinforcing steel. Within 24 hours prior to the placement of new concrete, exposed reinforcing steel and the faces of existing concrete shall be cleaned by abrasive blast cleaning. The Contractor shall repair and replace damaged or corroded reinforcement as required by this section. The Contractor shall place at least one zinc anode in the opening of each area to be patched or repaired, in accordance with Section 412.03(c) for Embedded Galvanic Anodes Immediately prior to placing new concrete, exposed reinforcing steel and faces of existing concrete shall be cleaned of all dust and debris by blowing with oil-free compressed air or hosing with water. A fine spray of moisture shall be applied to the exposed concrete surfaces. Faces of existing concrete shall be in a saturated surface dry condition prior to placing new concrete. Prior to placement of repair material the Contractor shall capture clear digital images or photographs of all repair areas. Images shall clearly demonstrate that the area to be repaired was prepared to the proper depth and with appropriate surface preparation. Images shall include measuring devices that clearly demonstrate the length, width, and depth of the repair area. Images shall be submitted to Engineer for inclusion in project records and will be a condition for payment.
2.Deteriorated Concrete Removal Plan The Contractor shall notify the Engineer a minimum of 3 working days before the beginning of any concrete repairs so that the areas to be repaired can be sounded in the presence of the Engineer. To preserve structural integrity and prevent unsafe structural conditions, the Contractor shall develop a plan for the removal of deteriorated concrete in superstructure and substructure elements. The plan shall be submitted to the Engineer for review after the elements are sounded and prior to beginning the work. The plan shall specify the order and size limits of areas of deteriorated concrete that may be removed at any one time. Concrete in the newly repaired areas shall attain a minimum design compressive strength of 3000 psi before adjacent concrete is removed. The cost of preparing the plan shall be included in the price bid for the appropriate items. Unless otherwise approved by the Engineer, the plan shall include the following limitations on concrete removal: • Reinforced Concrete Beams - the removal of concrete in the tension zone of a beam shall be less than 30% of the span length at any one time. • Prestressed Concrete Beams - the removal of concrete in the tension zone of a beam shall be less than 30% of the span length at any one time.412.03 556• Caps for Column Piers - the removal of concrete in the tension zone of a cap shall be less than 30% of the span between adjacent columns at any one time. • Cap Cantilevers for Column and Hammerhead Piers - the removal of concrete in the tension zone of a cap cantilever shall be less than 30% of the length of the cantilever at any one time. • Pier Columns - the removal of concrete in a pier column shall be less than 30% of the height of the column at any one time. • Columns in Multi-Column Piers - no more than 50% of the columns may be under repair at any given time.
3.Self-consolidating concrete (SCC), used in lieu of Class A4 concrete for superstructure repairs or Class A3 concrete for substructure repairs, shall adhere to these procedures. The Contractor shall demonstrate that he can produce satisfactory SCC that meets the Contract requirements by submitting documentation indicating the Contractor’ s successful experience in furnishing and placing SCC on similar size projects or structural elements, or by successfully trial batching at least 3 weeks prior to beginning placement operations. Such documentation shall list projects by date of completion, name or project reference number, client or owner, structural elements or type of unit placed, quantity of SCC furnished, names and experience of personnel, and current contact (owner or client) information for verification. The Contractor shall also demonstrate that SCC can be placed without segregation of the mix by a mock-up simulating the actual elements. The cost of the mock-up shall be included in the price bid for the appropriate items. Formwork shall be in accordance with Section 404 and designed for the full static head of concrete. A Concrete Technologist (such as the admixture supplier) experienced in the production of SCC or a representative of the SCC producer shall be present during placement. Concrete shall stay plastic and within the slump flow specified during placement operations. Concrete place - ment shall be conducted in such a manner that air is not encapsulated, segregation does not occur, and the SCC flows freely to thoroughly occupy the formwork throughout the duration of the placement. The Contractor shall field-test SCC in accordance with Section 217.11. Record all concrete test data and submit the test data to the Engineer. Consolidation is typically not necessary for SCC. However, the Contractor shall have internal vibrators on site in case internal vibration is needed due to delays in placement or if the con - crete has lower than expected slump flow and has to be placed to prevent the formation of a cold joint. The Contractor shall obtain prior approval by the Engineer if it is anticipated minimal vibration (external or internal) is required for proper consolidation due to congested reinforcement or space restrictions. Equipment for job site mixing of hydraulic cement concrete and HES concrete shall be approved by the Engineer prior to the start of the work. Concrete mixed at the job site shall be mixed in a High 412.03 557Performance V olumetric Mixer (HPVM) in accordance with Section 217.05(d) when the quantity of repair material is greater than 6 cubic feet. Concrete shall be constructed in accordance with Section 404 except that surfaces shall be finished and shaped to match existing adjacent surfaces. Concrete shall be Class A4 when used for super - structure work except prestressed concrete beams, and Class A3 when used for substructure work.
b.Bridge Superstructure and Deck Repairs:
1.Type A patching and Type A Patching (HES) shall consist of repairing the deck from the existing deck surface or milled surface to a depth that will not expose reinforcing steel. Materi - al placed in the patch shall be vibrated in place and shall be broom-finished. Prior to initial set, the material shall be scraped or cut with a trowel followed by a broom finish then immediately covered with moist burlap, which shall be kept moist until the deck is opened for traffic. Do not overfinish or place additional water on top of patch during finishing.
2.Type B patching and Type B Patching (HES) shall consist of repairing the deck from the existing deck surface or milled surface to a depth at least 1 inch below the top mat of reinforcing steel. Material placed in the patch shall be vibrated in place and shall be broom-finished. Prior to initial set, the material shall be scraped or cut with a trowel followed by a broom finish then immediately shall be covered with moist burlap, which shall kept moist until the deck is opened for traffic. Do not overfinish or place additional water on top of patch during finishing.
3.Type C patching and Type C Patching (HES) shall consist of repairing the deck from the existing deck surface or milled surface to its full depth. Forms may be suspended from reinforcing steel by wire ties for areas of less than 3 square feet. In the case of larger area openings, forms shall be supported by blocking. Sound concrete shall be removed to obtain a somewhat vertically shaped surface at the edges of the patch. Material placed in the patch shall be vibrated in place and shall be broom-finished. Prior to initial set the material shall be scraped or cut with a trowel followed by a broom finish then immediately covered with moist burlap, which shall kept moist until the deck is opened for traffic. Do not overfinish or place additional water on top of patch during finishing.
4.Epoxy-mortar patching shall be performed in accordance with the requirements for Type A patching to a depth up to and including 3/4 inch. The Engineer will approve the proportions of sand and epoxy to be used in the patching material. Surface areas to be patched shall be dry and primed with neat epoxy just prior to mortar placement. Mortar may be troweled into place to featheredges. The patched surface shall be sprinkled with sand before the epoxy sets or sandblasted just prior to placement of the seal to ensure bonding. When epoxy mortar is to be the finished riding surface, patches exceeding 8 feet in any longitudinal direction shall be tested in that direction in accordance with Section 404.04.
5.Crack repairs shall be performed using one of the following methods as specified on the plans:
a.Crack Repair Type A (V grooving) - Structural cracks and dormant cracks shall be V -grooved to a depth of approximately 1/2 inch and blown clean. The groove shall be filled with neat epoxy. At the Contractor’ s option, hydraulic cement concrete overlay material may be brushed into the groove in lieu of epoxy when hydraulic cement concrete overlay material is monolithically placed for Type A, B, or C patching or joint repairs.412.03 558 b. Crack Repair Type B (Epoxy injection) - The Contractor shall subject cracks to several blows with a five-pound hammer. At locations where a hollow sound is detected with the hammer, the Contractor shall remove loose, spalled or otherwise deteriorated unsound concrete. The crack shall then be blown clean with oil free compressed air and injection ports installed along the crack at 18 inches on center. The crack shall be surface sealed with Epoxy, Type EP-6 and allowed to fully cure according to manufacturer’s instructions prior to pressure sealing. After surface curing the crack, the Contractor shall internally pressure seal the crack with Epoxy, Type EP-4 LV Modified using slow, steady pressure from an injection gun capable of producing a fluid pressure of at least 100 psi. Injection of EP-4 L V Modified epoxy shall begin at the lowest injection port and shall be pumped until the epoxy reaches the next higher port. This process shall be repeated until the full length of the crack is pressure sealed. After the entire crack has been pressure sealed, injection port fittings shall be removed and the resulting holes filled with Epoxy, Type EP-6.
c.Crack Repair Type C (Gravity Filled Polymer Sealing) - Gravity fill polymer sealers shall be a high molecular weight methacrylate, epoxy or urethane material from the Ma - terials Division’ s Approved Products List 28. Concrete cracks in new work to be filled shall have reached the 28-day design compressive strength requirement, shall be dry and free of dust, dirt and other debris prior to filling. Cracks shall be air blasted with oil free compressed air prior to application of the sealer. The concrete surface temperature shall not be less than 55 degrees F when the sealer is applied. The sealer shall be applied during the lowest temperature period of the day, usually between 1 a.m. and 9 a.m., when the cracks are open to their greatest extent. Cracks wider than 1/25 inch shall be filled with dry No. 50 sieve size silica sand prior to placement of the polymer. The polymer shall than be applied directly to the cracks allowing time for the polymer to seep down into the cracks, then making additional applications until cracks are filled. The polymer material may also be spread over designated crack areas and worked into the cracks with a broom or squeegee. Excess polymer shall be brushed off the surface prior to the polymer hardening. Regardless of the application method used, the polymer shall be applied in sufficient quantity and applica - tions to fill cracks level. An application rate of 1 gallon per 100 linear feet or 100 square feet is usually adequate. Application of the polymer crack sealer shall be completed prior to grooving of the deck surface and grooving shall not be performed until the polymer has cured a minimum of 48 hours. The Contractor shall plan and prosecute the work in such a manner to protect persons, vehicles and the bridge structure from injury or damage. Armored joints shall be covered, scuppers plugged and cracks sealed from underneath or other protective measures implemented as necessary to protect traffic, waterways and bridge components. If polymer materials or solvents harm the appearance of bridge components, removal of such materials will be required as directed by the Engineer. Traffic will not be permitted on treated surfaces until tracking will not occur as determined by the Engineer.
d.Crack Repair Type D (Epoxy and Carbon Fiber Mesh) - The Contractor shall seal linear cracks and construction joints in hydraulic cement concrete bridge decks and overlays with epoxy and open grid carbon fiber mesh as directed by the Engineer.412.03 559Cracks shall be located and sealed at the oldest age that is practical as determined by the Engi - neer and prior to the final acceptance of the project and prior to opening the surface to traffic. Crack width shall be measured using a transparent crack comparator placed on the sur - face of the concrete. The width shall be at the oldest age that is practical as determined by the Engineer prior to opening the surface to traffic and prior to the final acceptance of the project. The width shall be measured and recorded within 3 hours after sunrise. Cracks with a width equal to or greater than 0.2 millimeter shall be marked for sealing. The surface of the concrete on which the carbon fiber mesh will be placed shall be cleaned in accordance with Section 431. The epoxy and aggregate shall be placed in accordance with the requirements for the first layer for Epoxy Concrete Overlay. The Contractor shall then dump and spread the mixed epoxy resin on the designated area for the placement of the 4-inch carbon fiber strip. Apply the epoxy at a minimum rate of 2-1/2 gallons per 100 square feet. Immediately place the 4-inch carbon fiber strip, precut to the required length, into the placed epoxy allowing the epoxy to saturate the carbon strip so as to penetrate through the openings in the carbon strip and thoroughly encapsulate the strip. A roller or squeegee may be used to assist penetration and to ensure the strip is pressed to the substrate and the epoxy is evenly spread. Use a squeegee to move adjacent epoxy over the strip for complete encapsula - tion. Broadcast aggregate to excess over all surfaces covered with epoxy. The Contractor shall plan and prosecute the work in such a manner to protect persons, vehicles and the bridge structure from injury or damage. In the event epoxy materials or solvents harm the appearance of bridge components, removal of such materials will be required as directed by the Engineer. Traffic will not be permitted on the treated surface during the curing period which is specified in Section 431.
6.Concrete superstructure surface repair shall include repairing raised medians, median barriers, beams, diaphragms, parapets, posts, rails, curbs, sidewalks, and other areas as designated on the plans. Superstructure surface repair shall be performed in accordance with the requirements herein. For unreinforced concrete elements where 2 inches or more of existing concrete is removed, the Contractor shall place 2 x 2-W1.4 x W1.4 welded wire fabric over the entire patch area. Welded wire fabric shall be anchored to expansion bolts at least 3/8 inch in diameter, which the Contractor shall place along the edges of the patch. The expansion bolts shall be spaced not more than 18 inches apart and shall be embedded at least 2 inches into the concrete. The minimum thickness of repair material over reinforcing steel, including expansion bolts and welded wire fabrics, shall be 2 inches unless otherwise specified. Unless otherwise specified, the Contractor shall have the option of using conventional hydraulic cement concrete or self-consolidating concrete for concrete superstructure surface repairs. Shotcrete will only be allowed when specified on the plans or approved in writing by the Engineer.
7.Joint opening repairs shall be performed as follows:
a.Expansion joint removal shall consist of removing and disposing of concrete, repairing and replacing reinforcing steel, and cleaning exposed surfaces by abrasive blasting.412.03 560 b. Expansion joint reconstruction and Expansion joint reconstruction (HES) shall consist of removing and disposing of existing concrete and any existing joint armor, repairing and replacing reinforcing steel as may be required by this section, preparing the contact surfaces, and furnishing and placing new concrete and reinforcing steel, in accordance with the plan details and the requirements herein.
c.Expansion joint preparation shall consist of removing and disposing of existing joint material, cleaning the joint by abrasive blasting, and saw cutting the joint when necessary. A saw guide shall be provided for all saw cutting. Sawing to a line or mark by visual unassisted means only will not be permitted. The saw guide shall be a template or track capable of controlling the saw in the desired direction to produce a clean, straight and true line.
d.Backwall reconstruction and Backwall reconstruction (HES) shall consist of removing and disposing of existing concrete and any existing joint armor, repairing and replacing existing reinforcing steel as may be required by this Section, preparing the contact surfaces, and furnishing and placing new concrete and reinforcing steel, and restoring backfill and disturbed pavement in accordance with the details and requirements herein or shown on the plans. The new concrete backwall shall have the same dimensions as the existing backwall being replaced. Exposed undamaged existing backwall reinforcing steel shall be abrasive blast cleaned and reused. When not included in other joint repairs, saw cutting of the joint shall consist of saw cutting concrete to the limits detailed in the plans.
8.Existing joint resealing shall be performed in accordance with Section 316 unless otherwise specified in the plans.
c.Embedded Galvanic Anodes shall consist of furnishing and installing galvanic anodes in deck patching, superstructure repairs, or substructure repairs as shown on the plans or as directed by the Engineer, confirming the electrical connection between anode tie wire and reinforcing steel, confirming/establishing the electrical continuity of all of the exposed reinforcing steel, wiring, and testing for the successful installation and performance of galvanic anodes. Unless otherwise shown on the plans or directed by the Engineer, galvanic anodes shall be placed in all deck patches, deep hydro-demolition applications, superstructure repairs, and substructure repairs. The removal of deteriorated concrete and placement of repair material shall be measured and paid for under the appropriate items for deck patching, superstructure repairs, and substructure repairs. At least 2 weeks prior to installation the Contractor shall submit to the Engineer for review a detailed plan for installation and placement of the anodes subsequent to the removal of the deteri - orated concrete during each construction stage. Anodes shall be spaced no greater than 18 inches on center along the periphery of the repair/patch area or as specified by the manufacturer. Final anode placement and incorporation into the work shall not proceed until the Engineer has accepted the Contractor’ s anode installation plan. The Engineer’ s acceptance of the Contractor’ s installation plan shall in no way relieve the Contractor of his responsibility for furnishing and installing a fully functional anode corrosion protection system that meets the criteria established in this specification and the other contract requirements.412.03 561A technical representative from the anode manufacturer shall be on site for a minimum of two (2) days during the initial startup of the anode installation for instruction and advice. The technical representative shall be available for subsequent visits as deemed necessary by the Engineer to insure continued compliance with the installation process. A technical representative from the anode manufacture shall be on site for final testing of the system.
1.Concrete Removal: The Contractor shall undercut all exposed reinforcing steel by removing concrete from the full circumference of the steel. The minimum clearance between the concrete substrate and galvanic anode shall be 3/4 inch to allow sufficient room for embedding mortar between the anode and concrete substrate. Concrete removal shall continue along the existing reinforcing steel until there are no visible signs of corrosion. Edge and surface conditioning of concrete:
a.Concrete patches shall be square or rectangular in shape with squared corners.
b.Saw cut the patch boundary 1/2 inch deep or less if required to avoid cutting reinforcing steel.
c.Create a clean, sound substrate by removing bond-inhibiting materials from the concrete substrate by high pressure water blasting or abrasive blasting.
2.Cleaning and Repair of Reinforcing Steel:
a.Clean exposed reinforcing steel of rust, mortar, etc. by abrasive blasting or other methods acceptable to the Engineer to provide sufficient electrical connection and mechanical bond.
b.If significant reduction in the cross section of the reinforcing steel has occurred, replace or install supplemental reinforcement as directed by the Engineer.
c.Secure loose reinforcing steel by tying tightly to other bars with steel tie wire.
3.Galvanic Anode Installation: Galvanic anodes shall be installed along the perimeter of the repair or interface at spacing as specified in the manufacturer’ s specifications or instructions, however, in no case shall the distance between anodes exceed 18 inches. The minimum concrete cover between the anode and the surface shall be 1 1/2 inches. The minimum distance between the anode and the concrete substrate shall be 3/4 inch.
a.Secure the galvanic anodes as close as possible to the patch edge using the anode tie wires. The tie wires should be tightened to allow little or no free movement.
b.If the anode is to be tied onto a single bar, or if less than 1 inch of concrete cover is expected, place anode behind the bar and secure to clean reinforcing steel.412.03 562 c. If sufficient concrete cover exists, the anode may be placed at the intersection between two bars and secured to each clean bar.
4.Electrical Continuity:
a.Confirm electrical connection between anode tie wire and reinforcing steel by measuring DC resistance (ohm, Ω) with a multi-meter.
b.Confirm electrical continuity of the exposed reinforcing steel within the repair area. If necessary, electrical continuity shall be established with steel tie wire.
c.Electrical continuity is acceptable if the DC resistance measured with multi-meter is less than 1 Ω.
5.Concrete Placement:
a.Embed the anodes in individual pockets of embedding mortar to form a conductive bridge to the concrete substrate. Embedding mortar shall completely surround the anode, filling all voids between the anode and the concrete substrate and reinforcing steel over a minimum area of 4 inches in diameter.
b.Insulating materials such as epoxy bonding agents shall not be used.
c.Following normal concrete repair procedures complete the repair with concrete, taking care not to create any air voids around the anode. Concrete material and installation shall conform to all anode manufacturer’ s specifications and instructions.
d.Deck Slab Closure shall consist of repairing bridge decks for link slabs at piers and deck extensions at abutments in accordance with the plan details and the requirements herein. This work shall consist of removing and disposing of existing concrete and any existing joint armor, removing and disposing of stud shear connectors within the limits of the slab closure for steel beams/girders, removing and disposing of stirrup bars within the limits of the slab closure for concrete beams/ girders, repairing or replacing existing reinforcing steel as may be required by the work described in this Section, preparing the contact surfaces, furnishing and placing expanded polystyrene, and furnishing and placing new reinforcing steel and concrete in accordance with the details and requirements herein. Exposed undamaged existing reinforcing steel shall be abrasive blast cleaned and reused. The Contractor shall develop a sequence of construction for deck slab closures to be used in con - junction with other related work items (bearing modification, etc.) which shall be submitted to the Engineer for review prior to performing the work. The cost of preparing the sequence of construc - tion shall be included in the price bid for deck slab closure.
e.Concrete Substructure Surface Repairs shall include repairing piers, wing blocks, abutments and other areas as designated on the Plans, removing and disposing of existing concrete, repairing or replacing existing reinforcing steel where required by the work described in this Section, preparing the contact surfaces, furnishing and placing a bond breaker when required, and furnishing and placing new reinforcing steel and concrete in accordance with the requirements herein. Exposed undamaged existing reinforcing steel shall be abrasive blast-cleaned and reused. Limits of repair and removal of damaged concrete shall be determined in accordance with Section 412.03(a) herein. Removal of concrete shall be to a depth as required by Section 412.03(a) herein 412.03 563or as specified on the plans or as directed by the Engineer. Welded wire fabric shall be installed in accordance with Section 412.03(b)6 herein. Concrete for substructure surface repair shall be Class A3 concrete or self-consolidating concrete cast within forms placed to match the original geometry of the substructure element. Finished and repaired concrete shall be flush with pre-existing concrete and no blisters or protrusions will be accepted. Shotcrete shall not be permitted unless approved by Engineer in writing. Repair materials shall conform to Section 217 and this specification.
f.Jacking and Blocking Beams shall consist of supporting beams during construction and may include jacking, blocking, and other approved methods of support in accordance with the require - ments herein. The Contractor shall develop a plan for jacking, blocking, and supporting beams which shall be submitted to the Engineer for review and approval. The plan shall be designed, prepared and sealed by a Professional Engineer holding a valid license to practice engineering in the Commonwealth of Virginia. The cost of preparing the plan shall be included in the price bid for Jacking and Blocking Beams. Unless approved by the Engineer in writing or specified on the plans, temporary support systems shall be designed to sustain traffic loadings in addition to dead load and temporary construction loads and all other anticipated loading while performing the work.
g.Shotcrete will be permitted only when specified for repairs or approved in writing for use in lieu of conventional hydraulic cement concrete or self-consolidating concrete. Shotcrete repairs shall be performed in accordance with Sections 412.02(e), 412.03(a), 412.03(b)6, 412.03(b)7d and 412.03(e) herein. The shotcrete mixture shall be prepackaged material from the Materials Division’ s Approved Products List 33, or ready mixed concrete containing at least Portland cement, silica fume, aggregates, and synthetic fibers. Admixtures and Class F fly ash or slag cement will be permitted. Any mixture other than approved mixtures shall have trial batch or historic data showing compli - ance with the specifications and will require approval by the Engineer before use. Synthetic fibers shall be 3/4 inch long polypropylene present in small quantities (minimum 1.5 lb/yd3) to control plastic shrinkage cracking. Any other type of fiber requires the prior approval of the Engineer. The minimum 28-day design compressive strength of shotcrete shall be 5,000 psi and the maximum permeability, 1,000 coulombs. Before construction, the Contractor shall submit for the Engineer’ s approval, the compressive strength and permeability data obtained from samples shot using the job material and equipment scheduled for use for the actual structure. Wire mesh shall not be required to hold the shotcrete in place. Shotcrete contractor shall have at least 3 years of experience in similar applications or shall be required to demonstrate qualification as required by the Engineer. Polymer modified shotcrete shall not be used unless permitted by the Engineer. Shotcrete cover over reinforcing steel shall be a minimum 2 inches except in transition areas where shotcrete is feathered to existing concrete with less than 2 inches of cover or where patches are made on existing concrete with less than 2 inches of cover over reinforcing steel. The Contractor shall submit for the Engineer’ s approval shotcrete mixture proportions and perfor - mance test data based on the materials to be used in the project. If appropriate recent test data do not exist, the Contractor shall prepare trial mixtures and submit the test results as obtained from tests specified in Section 412.03(g) 6.412.03 564Wet Process: Shotcrete subject to freezing and thawing shall have an air content of 7.0 percent ±1.5 percent as delivered to the job site. The materials for wet process shotcrete shall be mixed in accordance with Section 217 and applied within 90 minutes after batching. Dry Process: Solid ingredients for dry-mix shotcrete shall be predampened as needed and mixed in a batch type or continuous mixer. Most of the mixing water shall be added at the nozzle. Dry-mix shotcrete material shall be applied within 45 minutes after batching or predampening.
1.Equipment and Personnel:
a.Equipment: Shotcrete delivery equipment shall be approved by the Engineer before the commencement of the work. It shall be capable of discharging the shotcrete mixture in a continuously smooth stream of uniformly mixed ingredients. Air added at the nozzle shall be free from oil or other contaminants, and the air pressure shall be capable of delivering and maintaining sufficient nozzle velocity to all parts of the work.
b.Personnel: Nozzlemen with at least 100 hours of recent similar shotcrete application experience and supervisors with at least 3 years of recent similar shotcreting experience who can provide references showing satisfactory performance on at least three similar jobs may be approved as being qualified without gunning prequalifying panels. When proposed nozzlemen do not have the required experience or when the Engineer deems the work to be done of a sufficiently critical nature to require prequalifying tests for nozzlemen, approval will be based on the acceptance of shotcreting test panels as described in Section 412.03(g) 6 prior to the commencement of the work. The Engineer will observe the gunning of such test panels and judge the qualifications of the nozzleman on the basis of the texture, uniformity of work, and adequacy of the encasement of shotcrete around the reinforcement.
2.Surface Preparation:
a.The perimeter of all areas where concrete is removed shall be tapered at approximately a 45-degree angle except that the outer edges of all areas removed by chipping shall be saw cut perpendicular to the surface to a minimum depth of 1/2 inch to prevent featheredging unless otherwise approved by the Engineer.
b.Earth surfaces shall be trimmed to line and grade and shall have adequate support to prevent displacement during shotcrete placement. Shotcrete shall not be placed on an earth surface that is frozen, spongy, or subject to free running water at the time of the application of the shotcrete. Active seeps, drips, and flowing water shall be controlled by installation of suitable drain systems such that water pressure does not build behind shotcrete linings. The Contractor shall prevent excessive loss of mixing water from the shotcrete. This shall be accomplished by one of the following procedures:
1.Wet the soil prior to the time of gunning to the extent that it is damp but with no visible free water on the surface. Puddling, ponding, or freestanding water shall be eliminated from areas to be shotcreted.
2.As an alternative or when specified, install a moisture barrier system to inhibit the movement of moisture from the newly placed shotcrete into the earth. Wrinkling and folding of moisture barrier will not be permitted.412.03 565 c. Rock surfaces shall be free of loose material, debris, chips, mud, dirt, and other foreign matter. Surfaces shall be damp at the time of gunning, but puddling, ponding, or free - standing water will not be permitted.
d.Wood forms that are to be removed after use shall have a form release agent applied to prevent the absorption of moisture and inhibit the bond between shotcrete and the form.
3.Application:
a.When applied, shotcrete shall have a temperature of at least 50 degrees F but not more than 85 degrees F . The ambient and surface temperature shall be 50 degrees F and rising. At ambient air temperatures above 85 degrees F , the Engineer may require placement to be made at night or during early morning hours.
b.Shotcrete to be applied to uneven and previously repaired surfaces shall first be applied to any deep hole, deeply excavated sections, corners, or areas where rebound cannot escape or be blown free. The thickness of the shotcrete layer shall be such that no sloughing, sagging, tearing, or debonding will occur. Existing concrete shall be sandblasted within 24 hours of application, and the surface shall be damp just prior to application.
c.Where a layer of shotcrete is to be covered by a succeeding layer, it shall be first allowed to develop its initial set. Then, loose, uneven, or excess material, glaze and rebound shall be removed by brooming, scraping, or other means. Any surface deposits that take a final set shall be removed by abrasive blast cleaning, and the surface cleaned with an air-water blast from the nozzle. Curing compounds shall not be applied to surfaces that will be covered by an additional layer of shotcrete.
d.Shooting wires, ground wires, or other devices acceptable to the Engineer shall be used to control the line, grade, and thickness of the shotcrete.
e.During the shotcrete application, the nozzle shall be held perpendicular to and, when possible, 3 to 5 feet away from the receiving surface and rotated steadily in series of small oval or circular patterns. Whenever possible, sections shall be gunned in one layer to the full design thickness. However, for multiple layers of reinforcement, gunning of one layer of shotcrete may be required for each layer of reinforcement.
f.When encasing reinforcement, the nozzle shall be held closer than normal and at a slight, upward angle. The mixture may be wetter than normal but not so wet that sloughing behind the reinforcement will occur.
g.Vertical surfaces shall be gunned starting at the bottom. Rebound or previously expended material shall not be incorporated in the applied layer, and all such material shall be removed from the surface and work area prior to final set and before placement of shotcrete on adjacent surfaces. Shotcrete shall not be placed if drying or stiffening of the mixture is occurring.
4.Finishing: Prior to the initial set, the shotcrete surface shall be scraped or cut with a trowel or metal template to obtain an even and aesthetically acceptable appearance. The final finishing shall be with a wet sponge unless otherwise specified. Trowel or float smoothing will not be allowed.412.03 566 5. Curing: After gunning, the surfaces of shotcrete shall be protected from drying or cracking. When necessary, fogging shall be used prior to the application of moist curing or a curing compound. Shotcrete shall be moist cured for a period of at least 7 days or cured using a curing compound containing silane or siloxane conforming to Section 220. The rate of application shall be not less than 1 gallon of curing compound per 100 square feet of surface. The color of the curing compound shall be approximately that of the existing concrete.
6.Quality Assurance and Testing:
a.Preconstruction testing may not be required by the Engineer if documented that the crew to be used is qualified by virtue of previous long term experience or certification by the equipment manufacturer and that the mixture has been successfully used in recent similar work. Where required, preconstruction testing shall conform to the following: Test panels 24 inches by 24 inches by 4 inches deep containing steel reinforcement representative of that to be used on the project shall be prepared. Each crew shall gun two test panels with the mix design to be used on the project and for each gunning orientation to be encountered on the job. Panels shall be cured in the field in the same manner as the structure for 1 day and transported to the laboratory, where curing shall be continued until the time of testing. For shotcrete jobs of less than 200 square feet, the Contractor shall cut one of the test panels with a trowel or a metal template before the initial set in the presence of the Engineer to check visually for possible voids under the reinforcement. For larger jobs where specific evidence of good encasement of reinforcing bars is needed, the Contractor shall cut cores from the test panels after the concrete has hardened for at least 3 days. Cores shall be cut through the steel. The second panels for all jobs shall be used to determine the compressive strength of the applied shotcrete. Cores shall be 2 inches to 4 inches in diameter and shall be taken between the reinforcement. The cores will be tested by the Department at the specified age in accordance with ASTM C42.
b.In-place shotcrete shall be of uniform quality and free from segregation, honeycombing, sand pockets, sand lenses, sagging, dry patches, overspray, rebound, or incomplete encasement of reinforcement. Shotcrete shall also be free from delamination, cracking, or single voids with dimensions in excess of 1/4 inch. The Department reserves the right to test any section and reject shotcrete that does not conform to the specification requirements in terms of test values, soundings, and visual examination. The cost of any additional testing of suspect or disputed shotcrete that results in rejection shall be borne by the Contractor. The Contractor shall remove and replace or correct defective shotcrete to the satisfaction of the Engineer.
c.For compressive strength tests, one test panel shall be prepared for each day’ s production or for each 200 square feet of shotcreting by each crew using the same ingredients and gunning orientation as the shotcrete applied to the job. These panels shall be cured and delivered to the designated testing laboratory as specified earlier in this section. Test values on such panels shall equal or exceed the required 28-day strength requirements. Should failures occur, acceptance of the material will be determined by tests on cores from 412.03 567the installed work. A minimum of three cores shall be taken from the area in question. The average compressive strength of the cores taken from the work shall equal or exceed the specified strength for the class of shotcrete applied, and no single core shall have strength less than 85 percent of the specified value. If deemed necessary by the Engineer, the adequacy of the bond between the existing concrete and the shotcrete shall be determined by pull-off tests in accordance with ACI 503. A minimum bond strength of 250 psi will be accepted as satisfactory. Bond failure at less than 250 psi attributable to the failure of existing concrete will not be cause for rejection. The cost of up to three pull-off tests shall be the responsibility of the Contractor; additional pull-off tests will be the responsibility of the Department.
h.Anchor Bolt Replacement shall consist of temporary removal of the existing bearing assembly, core drilling, removing and disposing of existing bearing anchor bolts, furnishing and placing new anchor bolts with nuts and washers and grout, re-installation of existing bearing assembly, and providing any required environmental, worker and safety protection, and disposal of material in accordance with the details and requirements herein and Section 408. New anchor bolts shall be swedged type bolts of the same size and material as the anchor bolts being replaced. The new anchor bolts shall be grouted in place using a high-strength grout conforming to Section
218.03 (d).
A plan for removing existing anchor bolts and installing new anchor bolts shall be submitted to the Engineer for review prior to performing the work. The cost of jacking and supporting beams that may be required to accomplish this work will be paid for under the pay item Jacking and Blocking Beams.
i.Concrete Beam Repair shall consist of removing and disposing of existing concrete, repairing or replacing existing reinforcing steel where required by this Section, preparing the contact surfaces, furnishing and placing a bond breaker when required, and furnishing and placing concrete in accor - dance with the details and requirements herein. Exposed, undamaged existing reinforcing steel shall be abrasive blast cleaned and reused. Limits of repair and removal of damaged concrete shall be determined in accordance with Section 412.03(a) herein. Concrete for beam repair shall be Class A4 or self-consolidating concrete cast within forms placed to match the original geometry of the beam. Shotcrete will not be permitted unless approved by Engineer in writing. No beam repair shall be performed in a span lane that is under traffic unless supported by an approved temporary support system or unless approved in advance by the Engineer. The repaired Beam shall not be subject to live load until the new concrete has obtained a minimum compressive strength of 3,000 psi as determined by control cylinders. Cylinders used for control purposes shall be cured under conditions that are not more favorable than the most unfavorable conditions for the portions of concrete the cylinders represent. When repairing beam ends, the bearing area of the beam repair shall be placed against the existing bearing plate or the bridge seat if no bearing plate is present. If no bearing plate is present, a bond breaker shall be placed at the interface of the beam end and the seat.412.03 568The cost of any required temporary supports, including jacking and supporting beams that may be required to accomplish this work will be paid for under the pay item Jacking and Blocking.
j.Replace Concrete Curb shall consist of removing and disposing of existing concrete, repairing or replacing existing reinforcing steel as may be required by this Section, preparing the contact sur - faces, and furnishing and placing new Class A4 concrete and reinforcing steel in accordance with the details and requirements herein. The new concrete curb shall have the same dimensions as the existing curb that is being replaced. The locations of curb replacement shall be determined by the Engineer. Exposed undamaged existing curb reinforcing steel shall be abrasive blast cleaned and reused. The following incidental items shall be performed (when necessary) as part of the curb replacement work:
1.When curb replacement is being performed wooden blocks shall be used to support adjacent sections of curb that are not being replaced.
2.When concrete curb blocks are located under a section of curb that is being replaced, the concrete blocks shall be replaced. The cost of this incidental work shall be included in the price bid for Replace Concrete Curb.
k.Replace Concrete Rails, Type A shall consist of removing and disposing of existing rails and furnishing and placing new rail expansion boxes, new reinforcing steel, and new Class A4 concrete in accordance with the details shown on the plans and the requirements herein. The locations of rail replacements shall be as shown on the plans or as determined by the Engineer. Replacement rails shall aesthetically match the lines, architecture and length of the existing rail. Four new #4 conventional reinforcing bars shall be placed in all new rails, and these bars shall have 1 inch (minimum) cover between end of bar and end of rail. Rail expansion boxes shall be used at end of all new replacement rail sections.
l.Replace Concrete Rails, Type B shall consist of removing and disposing of existing concrete, repairing or replacing existing reinforcing steel as may be required by the work described in this Section, preparing the contact surfaces, and furnishing and placing new Class A4 concrete and reinforcing steel in accordance with the details in the Contract and requirements herein. The locations and lengths of rail replacements shall be determined by the Engineer. The dimensions of the rail shown in the contract may vary slightly from field conditions, and any differences noted shall be included in price bid for this item. All existing rail concrete shall be removed from the limits of a rail replacement length. Existing rail concrete shall be removed by the use of hand tools or pneumatic hammers weighing 15 pounds or less. Undamaged existing rail reinforcing steel shall be abrasive blast cleaned and reused. When rail replacement is being performed, wooden blocks shall be used to support adjacent sections of rail that are not being replaced. The cost of this work shall be included in the price bid for Replace Concrete Rails, Type B.412.03 569(m) Replace Concrete Post shall consist of removing and disposing of existing concrete, repairing or replacing existing reinforcing steel as may be required by the work described in this Section, preparing the contact surfaces, and furnishing and placing new Class A4 concrete and reinforcing steel in accordance with the details in the Contract and requirements herein. The new posts shall be constructed to the same detail and dimensions as the existing posts that are being replaced. The locations of post replacements shall be determined by the Engineer. Undamaged existing post reinforcing steel shall be abrasive blast cleaned and reused. The following incidental items shall be performed (when necessary) as part of the concrete post replacement work:
1.Rails adjacent to replacement posts shall be supported.
2.New rail expansion boxes shall be placed inside new posts that support Type A concrete rails.
3.Any existing name or date plates that are located in replacement posts shall be removed and reset in the new posts as directed by the Engineer. The cost of this incidental work shall be included in the price bid for Replace Concrete Posts.
n.Replace High Strength Grout shall consist of removing and disposing of existing grout, abrasive blast cleaning of the area, preparing the contact surfaces, and furnishing and placing new high strength grout in accordance with Section 218.03 (d) in the shear keys of pre-stressed concrete slab superstructures and/or pre-stressed concrete box beam superstructures in accordance with the details in the Contract and requirements herein and Section 405.
o.Reconstruct Bridge Seat (Type) shall consist of removing and disposing of existing concrete, repairing or replacing existing reinforcing steel as may be required by this Section, furnishing and placing new reinforcing steel, preparing the contact surfaces, and furnishing and placing new concrete in accordance with the details in the Contract and requirements herein and on the plans. Exposed undamaged existing reinforcing steel shall be abrasive blast cleaned and reused. Reconstruction of an existing beam seat shall not be performed in a span lane that is undertraffic. The repaired beam seat shall not be subject to live loads until the new concrete has obtained a minimum design compressive strength of 3,000 psi as determined by control cylinders. Cylinders used for control purposes shall be cured under conditions that are not more favorable than the most unfavorable conditions for the portions of concrete the cylinders represent. The cost of jacking and supporting beams that may be required to accomplish this work will be paid for under the pay item Jacking and Blocking Beams.
p.Concrete Surface Color Coating shall consist of furnishing and applying concrete surface color coating in accordance with this Section and in conformity with the details in the Contract and locations indicated on the plans. The color of the coating shall be similar to the Federal Standard Color Number specified on the plans or as approved by the Engineer. The Concrete Surface Color Coating shall be selected from the Material Division’ s Approved Products List 30. Except as otherwise specified on the plans, the concrete surface color coating shall be applied to the following surfaces of the bridge structure:412.03 570 1. Pier stems and caps from 6 inches below finished grade to the upper limits of the pier caps but excluding the top of the cap.
2.Exposed surfaces of abutment walls from finished grade of adjacent concrete slab slope protection or 6 inches below finished grade of embankment to and including the top of the wingwall, excluding bridge seats and portion of back wall between limits of exterior structural members.
3.All surfaces of parapet walls, the edge of deck slab and the underside of the bridge deck overhangs from the deck edge to the structural member. Concrete surface color coating shall be applied to exposed surfaces of other concrete structures as specified on the plans. Surface preparation and application shall be in accordance with the manufacturer’ s instructions, unless otherwise specified on the Plans or elsewhere in the Contract. The concrete surface color coating shall not be applied until all concrete placement operations for the particular structure have been completed. The concrete surface shall be clean, free of any curing agents, form release agents, foreign substances, or signs of efflorescence at the time of application. All work shall be performed by experienced workmen familiar with performing concrete finishing work and applying the materials specified. Surfaces not to be treated shall be protected from splatter. Color coating materials shall be delivered to the job site in sealed containers bearing the man - ufacturer’ s labels. Materials shall be mixed and applied in accordance with the manufacturer’ s printed instructions, two copies of which shall be furnished the Engineer.
q.Reinforcing Steel Bar Splicer (Bar Size) shall consist of furnishing and placing mechanical splicers for the specified reinforcing bar size in accordance with the details and requirements herein, Section 406 and as shown on the plans.
r.Parapet Closure (Type) shall consist of removing and disposing of existing concrete, repairing or replacing existing reinforcing steel as may be required by the work specified in this Section, preparing the contact surfaces, and furnishing and placing new concrete and new reinforcing steel in accordance with the details in the Contract and requirements herein. Exposed undamaged existing reinforcing steel shall be abrasive blast cleaned and reused.
s.Fiber Reinforced Polymer System shall consist of furnishing and installing a carbon fiber reinforced polymer (FRP) wrap system for repairing and/or strengthening of designated superstruc - ture or substructure members. The Plans or Contract will provide the flexural, shear, or axial strength requirements for the member to be repaired or strengthened. The Contractor shall submit the following documents to the Engineer for approval prior to beginning the work:
1.Working Drawings shall be submitted to the Engineer for review in accordance with Section
105.10 The working drawings shall be certified by a Professional Engineer holding a valid
license to practice engineering in the Commonwealth of Virginia. Working drawings shall 412.03 571include the type of FRP system, number of layers and orientation of all FRP materials, repair locations, relevant dimensions of the system and the work plan including the necessary preparations of the existing structure. The drawings must be accompanied by the design calculations, the MSDS and the manufacturer’ s system data sheet identifying mechanical, physical and chemical properties of all components of the FRP system; application guide, including the installation and maintenance procedures; and time schedule for various steps in the repair process. The installation procedure must clearly identify any environmen - tal and substrate conditions that may affect the application and curing of the FRP system. The design calculations shall be performed in accordance with the current AASHTO and ACI specifications and guidelines for FRP systems.
2.Quality Assurance Plan - The Contractor shall be responsible for developing and imple- menting a quality assurance plan for all FRP materials and processes scheduled for use on the project. The quality assurance plan must be submitted to and approved by the Engineer prior to beginning FRP operations on the project. The plan shall include specific procedures for per - sonnel safety, tracking and inspection of all FRP components prior to installation, inspection of all prepared surfaces prior to FRP application, inspection of the work in progress to assure conformity with specifications, quality assurance samples, inspection of all completed work including necessary tests for approval, repair of any defective work, and disposal and clean-up. Any part of the work that fails to comply with the Contractor’ s approved Quality Assurance Plan and the Contract requirements will be rejected by the Engineer, and shall be remedied, or removed and replaced by the Contractor at his own expense.
3.Qualifications of Contractor - Contractor/Sub-Contractor shall be approved by the Engineer for each FRP system scheduled for use on the project after providing the following necessary information:
a.Minimum of 3 years of documented experience in installing the designated FRP system or 15 documented similar field applications within the last 5 years with acceptable reference letters from respective Owners; and
b.Certificate of completed training from Manufacturer/Supplier for at least one field representative who will be present on site throughout the project
4.Manufacturer’s Representative: The Contractor shall have present during the installation of the FRP system, a manufacturer’ s representative, knowledgeable in the methods of instal - lation of the FRP system, for technical expertise and to certify that the Contractor’ s personnel installing the system are knowledgeable and are installing the system’ s components in accordance with the manufacturer’ s instructions. The Contractor shall also arrange to have the manufacturer’ s representative present during testing of the material by the Engineer. The manufacturer’ s representative shall certify that the system was properly installed at the completion of the insrtallation prior to final payment to the Contractor. All components of the FRP system must be delivered and stored in the original factory-sealed unopened packaging or containers with proper labels identifying the manufacturer, brand name, system identification number and date. Store catalysts and initiators separately. All components must be protected from dust, moisture, chemicals, direct sunlight, physical damage, fire, and temperatures outside the range specified in the system data sheets. Any component that has been stored in a condition different from that stated shall be considered unacceptable for use and must be properly disposed of.412.03 572All components of the FRP system, especially resins and adhesives, that have been stored longer than the shelf life specified on the system data sheet, shall not be used, and must be properly disposed of. All components of the FRP system, especially fiber sheets, must be handled with care accord - ing to the manufacturer’ s instructions to protect them from damage and to avoid misalignment or breakage of the fibers by pulling, separating, wrinkling, or folding the sheets. After cutting, sheets shall be either stacked dry with separators, or rolled gently at a radius no tighter than 12 inches or as recommended by the manufacturer. All components of the FRP system, especially resins and adhesives, must be handled with care to avoid safety hazards, including but not limited to skin irritation and sensitization, and breathing vapors and dusts. Mixing resins shall be monitored to avoid fuming and inflammable vapors, fire hazards, or violent boiling. The Contractor is responsible to ensure that all components of the FRP system at all stages of work conform to the local, state, and federal environmental and worker’ s safety laws and regulations. All deteriorated concrete shall be repaired in accordance with Section 412.03 (b) or Section
412.03 (e) as directed by the Engineer. Repair of deteriorated concrete in these areas will be
measured for payment as Concrete Superstructure Surface Repair or Concrete Substructure Surface Repair as appropriate. All defective reinforcing steel shall be repaired in accordance with the requirements herein. All cracks in the surface of the concrete wider than 0.01 inch and with a spacing less than 1’-6” or cracks wider than 1/8” shall be repaired in accordance with Section 412.03 (b)5b. Repairing cracks using epoxy injection will be measured for payment as Crack Repair, Type B. All irregularities, unevenness, and sharp protrusions in the surface profile shall be ground to a smooth surface with less than 1⁄32 inch deviation. Disk grinders or other similar devices shall be used to remove stain, paint, or any other surface substance that may affect the bond. V oids with diameters larger than 1⁄2 inch and depressions on the concrete surface deeper than 1⁄16 inch measured from a 12 inch straight edge placed on the surface, shall be filled with epoxy filler or other equal material as recommended by the FRP system manufacturer or approved by the Engineer. All inside and outside corners and sharp edges shall be rounded or chamfered to a minimum radius of 1⁄2 inch. Ridges, form lines, and sharp or roughened edges greater than 1⁄4 inch shall be ground down or filled with putty, as specified by the manufacturer of the FRP system. Obstructions and embedded objects shall be removed before installing the FRP system, as directed by the Engineer. Substrate concrete and finished surface of concrete shall be cleaned in accordance with the instructions or recommendations of the manufacturer of the FRP system and to the satisfaction of the Engineer. Cleaning shall remove any dust, laitance, grease, oil, curing compounds, wax, impregnations, stains, paint coatings, surface lubricants, foreign particles, weathered layers or any other bond-inhibiting material. If power wash is used, the surface shall be allowed to dry thoroughly before installing the FRP system. The cleaned surface shall be protected against re-deposit of any bond-inhibiting materials. Newly repaired or patched surfaces that have not cured a minimum of 7 days shall be coated with a water-based epoxy paint or other approved sealers.412.03 573The contact surfaces shall be completely dry at the time of application of the FRP system. The FRP system shall be installed in accordance with the recommendations of the manufac - turer of the FRP system. During installation of the FRP materials, the installer shall maintain a daily log. This log shall provide material tracking and process records for each installation and shall include the following information: • Structural element identification with project name, contract number, and installation date. • Materials information including product name, description, date of manufacture, time of expiration, and lot or batch numbers. • Fabrication, inspection and verification data for the manufacturing and construction operations including square footage of fabric and volume of epoxy used each day, num - ber of layers, thickness measurements, ambient temperature and humidity readings at the beginning, middle and end of each casing installation shift. One sample per lot or batch of composite material used on the project shall be provided to the Engineer to verify compliance with the specification requirements of the Contract. The sample(s) shall be at least 12” x 12” and 1 ply thick. It shall be fabricated in the same manner as the field-installed material and cured straight and flat under moderate tension and pressure. At the discretion of the Engineer, the sample may be fabricated at the construction site or in advance at the installer’ s facility in the presence of the Engineer or the Engineer’ s designee. The sample shall be cured at 70 degrees F (min.) for a period of 7 days prior to testing. In addi - tion, a material specimen shall be taken as a thickness and glass transition temperature sample from each installed column casing after curing and prior to final epoxy coating. Field sample(s) shall be taken, in the presence of the Engineer, no sooner than 7 days after installation from a location on the structure designated by the Engineer. A copy of the test results shall be furnished to the Engineer within 60 days following sample fabrication. If test values fail to conform to any of the project specific requirements, the Engineer will make a determination regarding the disposition of the affected element. Such determination may include complete removal and reapplication at no cost to the Department. After at least 24 hours for the initial cure of the resin, the Engineer will perform a visual inspection of the structure surface for any swelling, bubbles, voids, or delamination. If an air pocket is clearly evident or suspected, an acoustic tap test will be carried out with a hard object to identify delaminated areas by sound, with a frequency of at least one strike per one square foot. Defects will be addressed as follows:
a.Epoxy Injection of Small Defects - Small entrapped voids or surface discontinuities no larger than 1⁄4 inch in diameter shall not be considered defects, and will not require corrective action, unless these occur next to edges or when there are more than 5 such defects in an area of 10 square feet or otherwise directed by the Engineer. Small defects of sizes between 1⁄4 and 1 1⁄4 inches in diameter shall be repaired using low pressure epoxy injection, as long as the defect is local and does not extend through the complete thickness of the laminate in case of multiple ply FRP systems. If any delamination growth is suspected between the FRP plies due to injection, the procedure shall be halted, and repair shall follow the requirements for Patching of Minor Defects.412.03 574 b. Patching of Minor Defects - Minor defects are those with diameters between 1 1⁄4 and 6 inches, and a frequency of less than 5 per any unit surface area of 10 square feet. The area surrounding the defect(s) to an extent of at least 1 inch on all sides shall be carefully removed. The area shall be wiped cleaned and thoroughly dried. The area shall then be patched by adding an FRP patch of the same type of the original laminate extending at least 1 inch on all sides of the removed area. Repair can also be conducted using the procedure for Replacement of Large Defects.
c.Replacement of Large Defects - Defects larger than 6 inches in diameter shall be carefully marked and scarfed out extending to a minimum of 1 inch on all sides. Scarfing shall be progressive through the layers, in the case of multi-ply FRP systems until past the defective area. In case the defect extends to the first FRP ply adjacent to the concrete, the entire thickness of FRP and primer shall be removed. The substrate shall be appropriately prepared and primer re-applied after ensuring that the surface and FRP are clean and dry. Application of a new FRP system within the scarfed area shall follow procedures for the original FRP system, except that an additional layer extending a minimum of 6 inches on all sides of the scarfed area shall be added as a patch. Once cured, the protective coating shall be applied over the entire area. After at least 24 hours for the initial cure of the resin and before applying the protective coating, the Engineer will perform direct pull-off tests on the structure following ASTM D4541 procedures to verify tensile bond between the FRP system and concrete. Test locations and sampling frequency shall be as specified on the Contract documents, or as recommended by the manufacturer and approved by the Engineer. At a minimum, three pull-off tests with at least one test per span or one test per 1000 square feet of the FRP system, and one test per substrate concrete type will be performed. Inspect failure surface of the core specimen to ensure that it is by cohesive failure within concrete. Failure at the bond line at tensile stresses below 200 psi is unacceptable. If one or more of the pull-off tests is found unacceptable, the work will be rejected, and repair will follow Replacement of Large Defects. Repair cored areas will follow Patching of Minor Defects. Test locations shall be filled with thickened epoxy as recommended by the manufacturer of the FRP system after all testing is completed and verified. Exposed surfaces of the FRP material, including surfaces 2 feet below ground, shall be cleaned and then epoxy-coated with a minimum of two coats of Epoxy Type EP- 3T. The coated material shall be protected from rainfall or water for a minimum of 24 hours following epoxy application.
412.04 Measurement and Payment
V olumes outlined by the completed excavation, formwork, and surfaces of the existing concrete will be measured prior to concrete placement so that quantities can be accurately computed. Hydraulic cement concrete for the class specified will be measured and paid for in accordance with Section 404. Types A, B, and C patching; Types A, B, and C patching (HES); and concrete substructure or superstructure surface repair for the type specified will be measured in square yards of surface area and will be paid for at the contract unit price per square yard for the type specified. This price shall include furnishing and placing concrete to fill the prepared areas.412.03 575Deck slab closure will be measured in square yards of deck area on which the slab closure occurs and will be paid for at the contract unit price per square yard. Epoxy-mortar patching will be measured in gallons of epoxy-mixed system used as a binder for mortar in place and for priming prior to application of epoxy mortar and will be paid for at the contract unit price per gallon. Expansion joint removal, expansion joint reconstruction, expansion joint reconstruction (HES), expansion joint preparation, backwall reconstruction, and backwall reconstruction (HES) will be measured in linear feet and will be paid for at the contract unit price per linear foot. This price shall include furnishing and placing high early strength concrete to fill the prepared areas for expansion joint reconstruction and backwall reconstruction. Saw cutting, when a pay item, will be measured in linear feet of concrete sawed and will be paid for at the contract unit price per linear foot. Saw cutting that is incidental to the removal of concrete for repairs will not be measured for separate payment, and the cost thereof shall be included in the contract unit price of the appropriate items. Jacking and blocking beams as specified on the plans or as directed by the Engineer, when a pay item, will be measured in units of each and will be paid for on an each basis per bearing location regardless of the number of lifting operations per jack. Crack repair (Type A, B, & D) will be measured in linear feet and will be paid for at the contract unit price per linear foot. Crack repair, Type C will be measured in linear feet or square yards as specified on the plans and will be paid for at the contract unit price per linear foot or square yard. Shotcrete (Type), when specified as a pay item, will be measured in square feet or cubic feet of surface to which it is applied and will be paid for at the contract unit price per square foot or per cubic foot for the type specified. Embedded galvanic anode will be measured in units of each and paid for at the contract unit price per each. This price shall include furnishing and installing anode, furnishing and installing tie wires and reinforcing steel where necessary, all surface cleaning and preparation to perform the work, testing, and on-site services of the galvanic anode manufacturer’ s technical representative. Anchor Bolt Replacement will be measured in units of each and will be paid for at the contract unit price per each. Beam End Repair will be measured in units of each beam end and will be paid for at the contract unit price per each. Replace Concrete Curb will be measured in linear feet and will be paid for at the contract unit price per linear foot. Replace Concrete Rails (Type) will be measured in linear feet and will be paid for at the contract unit price per linear foot for the type specified. Replace Concrete Post will be measured in units of each and will be paid for at the contract unit price per each. Replace High Strength Grout will be measured in linear feet and will be paid for at the contract unit price per linear foot.412.04 576Reconstruct Bridge Seat (Type) will be measured in units of each and will be paid for at the contract unit price per each for the type specified. Concrete Surface Color Coating will be will be measured in square yards of surface area and will be paid for at the contract unit price per square yard which price shall be full compensation for preparation of surfaces and for furnishing and applying coating. Reinforcing Steel Splicer (Bar Size) will be measured in units of each and will be paid for at the contract unit price per each for the bar size specified. Parapet Closure (Type) will be measured in units of each and will be paid for at the contract unit price per each for the type specified. Fiber Reinforced Polymer Wrap will be measures in units of square feet and will be paid for at the contract unit price per square foot. These prices shall include cutting, drilling, hammering, and all other work involved in the completely removing and disposing of existing concrete and other materials necessary to provide for joining the new and old portions of the structure in accordance with the plans or as directed by the Engineer. The contract unit price shall also include dowels or other approved anchoring devices, disposing of debris, surplus, or other unsuitable material, cleaning and repairing reinforcing steel, and welded wire fabric if necessary. If shotcrete is used, the price shall also include furnishing and incorporating fibers. Payment will be made under: ————————————————————————————— ————————Pay Item Pay Unit————————————————————————————— ————————Patching (Type) Square yard
H.E. S. Patching (Type) Square yard Deck slab closure Square yard Epoxy-mortar patching Gallon Concrete substructure surface repair Square yard Concrete superstructure surface repair Square yard Expansion joint removal Linear foot Expansion joint reconstruction Linear foot Expansion joint reconstruction (HES) Linear foot Back wall reconstruction Linear foot Back wall reconstruction (HES) Linear foot Expansion joint preparation Linear foot Saw cutting Linear foot Jacking and blocking beams Each Crack repair (Type) Linear foot or square yard Pneumatically applied mortar Square foot Shotcrete (Type) Square foot or cubic foot Embedded galvanic anode Each Anchor bolt replacement Each Beam end repair Each Replace concrete curb Linear foot Replace concrete rails Type ( ) Linear foot Replace concrete post Each Reconstruct Bridge Seat Type ( ) Each412.04 577————————————————————————————— ————————Pay Item Pay Unit————————————————————————————— ———————— Replace High Strength Grout Linear foot Reinforcing Steel Splicer (Bar Size) Each Parapet Closure (Type) Each Fiber Reinforced Polymer Wraps Square foot Concrete Surface Color Coating Square yard————————————————————————————— ———————— SECTION 413—DISMANTLING AND REMOVING EXISTING STRUCTURES OR REMOVING PORTIONS OF EXISTING STRUCTURES
413.01 Description
This work shall consist of dismantling and removing all or portions of existing structures in accordance with these specifications and in conformity with the lines, grades, and details shown on the plans or as established by the Engineer. The Contractor shall make all necessary notifications, including, but not limited to, the National Emission Standards for Hazardous Air Pollutants (NESHAPs) demolition/ renovation notification to the Virginia Department of Labor and Industry, amended notifications, and obtain any necessary permits in accordance with all applicable local, state, and federal laws and regulations. The Contractor shall protect the public and the environment from leaded paint or other hazardous material encountered in the work.
413.02 Procedures
a.Dismantling and Removing Existing Structures: Dismantling and removing existing structures shall include removing the entire superstructure, substructure, and slope protection. The substruc - ture shall be removed down to the streambed or to an elevation of at least 2 feet below the natural ground or finished grade of embankment that is to remain in place unless otherwise indicated on the plans. Removal shall include any part of the substructure or foundation piling that will interfere with the new construction. The substructure shall be removed to or below the bed of the stream as required by the U.S. Coast Guard for bridges crossing streams under the jurisdiction of the U.S. Coast Guard.
1.Dismantling structures for retention by the Contractor: Removed materials shall become the property of the Contractor and shall be removed from the project. The Contractor shall assume all personal and property liability associated with such materials and shall protect and save harmless the Department from any and all damages and claims associated with the dismantling, handling, transportation, storage, or use of such materials. The Department does not warrant the nature, condition, or the physical or chemical characteristics of the materials.
2.Dismantling structures for retention by the Department: The Contractor’ s dismantling operations shall be according to a method approved by the Engineer and shall be performed in a manner that will preserve the existing condition of the materials. Units shall be match marked for re-erection according to an approved diagram provided by the Department.413.02
Source: Virginia Road and Bridge Specifications, 2020 Edition. Pages 579–604 of 1,065.