459404.02 Preboring not shown on the plans and not specified by the Engineer will not be measured for payment. Preboring shown on the plans will be measured in linear feet for the particular size and type of pile for which preboring was specified and will be paid for at the contract unit price per foot. This price shall include performing preboring operations including disposing of surplus material, and erosion and siltation controls when required as a result of the preboring operations. Payment will be made under: ——————————————————————————Pay Item Pay Unit——————————————————————————Pile (Type and size) Linear foot Pile point for (Size and type) pile Each Driving test for (Size and type) pile Linear foot Dynamic Pile Test Each Loading test for (Size and type) pile Each Preboring (Size and type) pile Linear foot—————————————————————————— SECTION 404—HYDRAULIC CEMENT CONCRETE OPERATIONS
404.01 Description
This work shall consist of furnishing and placing hydraulic cement concrete in accordance with these specifications and in conformity with the dimensions, lines, and grades shown on the plans or as established by the Engineer.
404.02 Materials
a.Concrete shall conform to Section 217 of the Specifications. Aggregate used in concrete for bridge decks shall be nonpolishing. All concrete shall be tested for permeability in accordance with Section 217 of the Specifications.
b.Curing materials shall conform to Section 220.
c.Concrete admixtures shall conform to Section 215. Concrete admixture use shall conform to Sections 215 and 217.
d.Corrugated metal bridge deck forms shall be galvanized steel conforming to ASTM A653, Grade SS40, SS50, or SS80, and shall be coating designation G165. Supports, closures, and other fabri - cated parts shall conform to ASTM A653, Grade SS33, SS40, SS50, or SS80, and shall be coating designation G165.
e.Anchor bolts shall conform to Section 226.
f.Reinforcing steel shall conform to Section 223.
g.Watersto ps shall conform to Section 212. 460404.03
404.03 Procedures
a.Forms: On concrete or steel beam bridges, the Contractor shall have the option of using corrugated metal bridge deck forms or wood forms to form that portion of bridge decks between beams unless otherwise specified on the plans. However, corrugated metal forms shall not be used to form overhangs or portions of slabs where a longitudinal joint occurs between beams or girders. The Contractor shall submit calculations and layout details of the overhang supports and formwork, including fabrication and erection details, to the Engineer for review in accordance with Section
105.10 Overhang formwork details shall be signed and sealed by a Professional Engineer, holding
a valid license to practice engineering in the Commonwealth of Virginia. Devices for supporting forms of any type shall not be welded to steel beams or girders unless specified on the plans. Formwork shall be mortartight and of sufficient rigidity to prevent distortion attributable to the pressure of the concrete and other loads incidental to construction operations. Forms for exposed surfaces shall have a form liner of an Engineer approved type and shall be mortartight. Forms for exposed surfaces below the bottom of slabs of bridges, including substructures, and on endwalls and wingwalls of culverts down to an elevation of 1 foot below low water or 2 feet below the final ground line above water shall be faced with metal, plyboard, or other approved smooth-faced material constructed to provide a minimum of joints and prevent leakage. Concrete shall present a uniform and smooth surface without requiring touch-up or surface finishing upon removal of forms. Uneven joint protrusions of more than 1/8 inch shall be removed. Forms shall be filleted 3/4 inch at sharp corners and given a bevel or draft in the case of projections, such as girders and copings, to ensure easy removal. Metal ties or anchorages within the form shall be constructed to permit their removal to a depth of at least 1 inch from the face without damage to the concrete. If ordinary wire ties are permitted, wires shall be cut back at least 1/4 inch from the face of the concrete with chisels or nippers upon removal of forms. Fittings for metal ties shall be of such design that cavities left upon their removal will be the smallest size possible. Cavities shall be filled with cement mortar, and the surface left sound, smooth, even, and uniform in color. Forms shall be set and maintained true to line. When forms appear to be unsatisfactory, either before or during concrete placement, the Engineer may order the work stopped until defects have been corrected. The shape, strength, rigidity, watertightness, and surface smoothness of reused forms shall be maintained at all times. Warped or bulged lumber shall be resized before being reused. For narrow walls and columns where the bottom of the form is inaccessible, the lower form boards shall be left loose so that they may be removed for cleaning immediately before concrete placement. Forms shall be treated with an approved oil or form-coating material or thoroughly wetted with water immediately before concrete placement. For rails or other units with exposed faces, forms shall be treated with an approved oil or form-coating material to prevent adherence of concrete. Material that will potentially adhere to or discolor concrete shall not be used. Forms shall be maintained at a temperature that will not adversely affect curing of concrete. 461404.03 Formed voids in concrete shall be of accurate dimensions and locations so that the thickness of sur - rounding concrete shall not be reduced from plan dimensions. Methods of positioning void forms and placing surrounding concrete shall be subject to the approval of the Engineer prior to their use. Bridge deck slabs shall be constructed in a manner so that the thickness of the finished slab shall be not less than the thickness shown on the plans or more than the thickness plus 1/2 inch.
1.Corrugated metal bridge deck forms: If the Contractor elects to use corrugated metal bridge deck forms, the Contractor shall submit details of the forms, including fabrication and erection details, to the Engineer for approval in accordance with Section 105.10. Forms shall be designed and erected in accordance with the following:
a.Design: The thickness of forms shall be at least 20 gage (0.037 inch). The unit working stress in the sheet metal and supporting units shall be not more than 0.725 of the specified minimum yield strength of the material furnished. In no case shall it be more than 36,000 pounds per square inch. The maximum stress under a design load equal to the weight of the forms and plastic concrete plus a construction live load of 50 pounds per square foot shall be not more than the unit working stress for the material furnished. Deflection of forms under the weight of the form, plastic concrete, and reinforcement shall be not more than 1/180 of the span of the forms or 1/2 inch, whichever is less. In no case shall the loading be less than 120 pounds per square foot total. When the actual dead load attributable to the use of metal bridge deck forms is more than the design allowance for construction tolerances and methods shown on the plans, the Contractor shall strengthen the beams or girders to the extent necessary to maintain the design live load rating of the bridge and shall submit supporting information and calcula - tions to the Engineer for review.
b.Erection: The Contractor shall install forms in accordance with reviewed fabrication and erection plans. Field cutting of forms, supports, and closures at expansion joints, diaphragms, and abutments in skewed areas or in any area where girders or beams are not parallel shall be performed with saws or shears. The outstanding leg of the support angle, channel, or other device shall be not more than 3 inches. Form sheets shall not rest directly on the top of the stringer or floor beam flanges. Sheets shall be securely fastened to form supports and shall have a minimum bearing length of one inch at each end. Form supports shall be placed in direct contact with the stringer or floor beam flange by hangers or clips. Attachment of the forms to the form supports shall be made by permissible welds, screws, clips or other approved means. Fasteners along the ends and edges of form sheets shall be spaced at intervals not to exceed 18 inches. Welding and welds shall conform to Section 407.04 except that 1/8-inch fillet welds will be permitted. Permanently exposed form metal whose galvanized coating has been damaged shall be repaired in accordance with Section 233. Corrugated metal forms shall be positioned such that the specified cover for the reinforcing steel and minimum design slab thickness are maintained above crests of the corrugation. 462404.03 Transverse construction joints shall be located at the bottom of a flute, and 1/4-inch weep holes shall be field drilled at not more than 12 inches on center along the line of the joint. Closures at edges of forms parallel to beams or girders shall be made by crimping corrugations. Closures at skewed ends may be of the serrated or channel type. The design span of the sheet shall be the clear span of the form plus 2 inches measured parallel to form flutes. The permissible form camber shall be based on the actual dead load condition. Camber shall not be used to compensate for deflection in excess of the foregoing limits. Physical design properties shall be computed in accordance with AISI specifications for the design of cold-formed steel structural units.
c.Inspection: After concrete has been in place for at least 2 days, the Contractor shall sound at least 50 percent of the area of at least 25 percent of the individual form panels using a moderate blow administered with a carpenter’ s hammer. The Engineer will randomly select individual form panels to be sounded. Areas of questionable soundness shall be exposed by removing forms. The amount of sounding and form removal required will be adjusted as the work progresses according to conditions detected by the investigation. When procedures, materials, or equipment used during placement of concrete warrant additional inspection of the underside as determined by the Engineer, the Contractor shall remove at least one form panel at each location selected by the Engineer. If the initial inspection reveals inferior workmanship or unsatisfactory material as determined by the Engineer, additional panels shall be removed to ascertain the extent of the deficiency. The Contractor will not be required to replace metal forms at locations where sections of forms are removed for inspection purposes. However, adjacent metal forms and supports shall be repaired to the extent necessary to render their attachment secure. The Contractor shall provide facilities required for the safe and convenient conduct of the Engineer’ s inspection.
b.Falsework and Centering: The Contractor shall have a Professional Engineer (holding a valid license to practice engineering in the Commonwealth of Virginia) inspect the completed falsework assembly supporting a bridge superstructure prior to placing loads. The Professional Engineer shall provide a certification, based upon visual inspection of the completed falsework assembly, that the falsework assembly conforms to the approved working drawings. However, such certification shall not require an exhaustive inspection or testing or make the Professional Engineer liable for any deficiencies in workmanship or materials employed by the Contractor or for such conditions that cannot be ascertained from a visual inspection. Falsework shall be designed and constructed to provide the necessary rigidity and to support the loads without appreciable settlement or deformation. The Contractor may be required to employ screw jacks or hardwood wedges to take up settlement in the formwork either before or during con - crete placement. A design weight of 150 pounds per cubic foot shall be assumed for fresh concrete. Falsework that cannot be founded on a satisfactory footing shall be supported on piles that are spaced, driven, and removed in a manner approved by the Engineer. 463404.03 Falsework shall be set in a manner so that after its removal the finished structure will have the finished grade specified or indicated on the plans. Correction for dead-load deflection of cast-in- place concrete beams and slab spans shall be provided for by applying an upward parabolic camber having an ordinate at midspan of 1/8 inch per 10 feet of span length. Falsework-supporting elements shall remain in place until concrete in the element has attained at least the minimum 28-day design compressive strength. Arch centering shall be constructed according to centering plans approved by the Engineer. Provision shall be made by means of suitable wedges, sand boxes, or other devices for gradual lowering of centers and rendering the arch self-supporting. When directed by the Engineer, centering shall be placed on approved jacks to take up and correct settlement that may occur after concrete placement has begun.
c.Placement and Consolidation: Individual placements of more than 25 yards of concrete shall be at the following rate: Quantity (cu yds) Min. Placement Rate 26-80 25%/hr Over 80 20 cu yds./hr. If corrugated metal bridge deck forms are used in lieu of removable forms, concrete placement shall proceed in the direction opposite that of form placement. Concrete shall be placed as soon as practicable after forms are prepared and excavation is completed. Water shall be removed from excavations before concrete is placed. Flowing water within the excavation shall be diverted outside concrete areas to a sump. Before concrete is placed, sawdust, chips, dirt, other debris and temporary struts and braces shall be removed from the space to be occupied by concrete. Removable forms shall be thoroughly wetted, oiled, or treated with an approved form-coating material. The depth and character of foundations and the placing of reinforcing steel shall have been approved by the Engineer. Concrete shall be placed in forms immediately after mixing. Concrete that does not reach its final position in forms within the time specified in Section 217 shall not be used. The method of placement shall be such as to avoid the possibility of segregating ingredients and displacing reinforcement or void forms. The use of long chutes for conveying concrete from the mixing plant to forms will be allowed only with the written permission of the Engineer. If chutes are allowed and the quality of concrete as it reaches the forms or the methods of placing it therein are not satisfactory, the Contractor shall, upon direction from the Engineer, discontinue the use of chutes and re-equip his operation for placing concrete in a satisfactory manner. Where steep slopes are required, chutes shall be equipped with baffle boards. When pipes are used, they shall be kept full of concrete and have their lower ends buried in fresh concrete where nec - essary to prevent an excessive flow rate. Chutes, troughs, and pipes shall be kept clean and free from coatings of hardened concrete by thorough flushing with water after each run. Water used for flushing shall be discharged clear of concrete in place and filtered prior to entry into state waters. Open troughs and chutes shall be metal or lined with metal and shall extend as nearly as possible to 464404.03 the point of deposit. When discharge must be intermittent, a hopper or other device for regulating discharge shall be provided. Dropping concrete a distance of more than 5 feet or depositing a large quantity at any point and running or working it along forms will not be permitted. However, the 5-foot limitation will not apply to dropping concrete into forms for walls of box culverts, catch basins, drop inlets, or endwalls unless there is evidence of segregation. Concrete placement shall be regulated so that pressures caused by the presence of fresh concrete shall be not more than those used in the design of forms. Embedded materials shown on the plans shall be installed during each stage of concrete operations and suitably supported and maintained in the correct position. Reinforcement shall be placed in accordance with Section 406.03(d). Care shall be taken to fill each part of a form by placing concrete as near its final position as possi - ble, working coarse aggregates back from forms, and moving concrete under and around reinforcing bars without displacing them. After concrete has taken its initial set, care shall be taken to avoid jarring forms or placing strain on the ends of projecting reinforcement. Concrete shall be thoroughly consolidated during and immediately following placement. Consolida - tion shall be accomplished by mechanical vibration subject to the following provisions:
1.Vibration shall be internal to the concrete but not applied directly to reinforcement or formwork.
2.Vibrators shall be of a type and design approved by the Engineer.
3.The intensity of vibration shall visibly affect a mass of concrete over a radius of at least 18 inches.
4.The Contractor shall provide a sufficient number of vibrators to consolidate each batch imme- diately after it is placed in forms.
5.Vibrators shall be manipulated to work concrete thoroughly around reinforcement and embedded fixtures and into corners and angles of forms. Vibration shall be applied at the point of deposit and in the area of the freshly placed concrete. Vibrators shall not be pulled through concrete and shall be inserted and withdrawn slowly and maintained nearly vertical at all times. Vibration shall be of sufficient duration and intensity to consolidate concrete thoroughly but shall not be continued so as to cause segregation. Vibration shall not be continued at any one point to the extent that localized areas of grout are formed. Application of vibrators shall be at points uniformly spaced and not further apart than twice the radius over which the vibration is visibly effective.
6.Vibration shall not be applied directly or indirectly to sections or layers of concrete that have hardened to the degree that it ceases to be plastic under vibration. Vibration shall not be used to make concrete flow in forms, and vibrators shall not be used to transport concrete in forms.
7.Vibration shall be supplemented by such spading as is necessary to ensure smooth surfaces and dense concrete along form surfaces and in corners and locations inaccessible to vibrators.
8.These specifications shall apply to filler concrete for steel grid floors except that vibration shall be applied to the steel. 465404.03
9.These specifications shall apply to precast piling, concrete cribbing, and other precast units except that the manufacturer’ s methods of vibration may be used if approved by the Engineer. When vibrating is not practicable, concrete shall be consolidated and its faces well spaded by continuous working with a suitable tool in a manner acceptable to the Engineer. Concrete shall be placed in continuous horizontal layers not more than 12 inches in thickness; however, slabs shall be placed in a single layer. When it is necessary in an emergency to place less than a complete horizontal layer in one operation, the layer shall terminate in a vertical bulkhead. In any given layer, separate batches shall follow each other so closely that each one shall be placed and consolidated before the preceding one has taken initial set. Each layer of concrete shall be left rough to secure efficient bonding with the layer above. A succeeding layer placed before the underlying layer has become set shall be consolidated in a manner to prohibit the tendency to produce a construction joint between layers. Layers placed at the end of one day’ s work or prior to temporarily discontinuing operations shall be cleaned of laitance and other objectionable material as soon as the surface has become sufficiently firm to retain its form. The top surface of concrete adjacent to forms shall be smoothed with a trowel. Horizontal layers located to produce a construction joint at a location wherein a feather edge might be produced in the succeeding layer shall be formed by inset formwork so that the succeeding layer will end in a body of concrete having a thickness of at least 6 inches. The work on any section or layer shall not be stopped or temporarily discontinued within 18 inches below the top of any face unless the details of the work provide for a coping having a thickness of not more than 18 inches, in which case the construction joint may be made at the underside of the coping at the option of the Engineer. Care shall be taken when placing concrete to avoid coating reinforcing steel, structural steel, forms, and other items that extend into areas to be involved in a subsequent placement. If coating of steel does occur, no attempt shall be made to remove the mortar until after the concrete steel bond of the earlier placement has developed sufficiently to withstand a cleaning operation. Any coating of mortar on deformed bars that cannot be removed by hand brushing with a wire bristle brush or a light chipping action will not have to be removed. The method and manner of placing concrete shall be regulated so as to place construction joints across regions of low shearing stress and in locations that will be hidden from view to the greatest extent possible. Placing and consolidating concrete shall be conducted to form a compact, dense, impervious mass of uniform texture that will show smooth faces on exposed surfaces. Any section of concrete found to be defective shall be removed or repaired as directed by the Engineer. If concrete operations are permitted to extend after sunset, the work area shall be brightly lighted so that all operations are plainly visible.
1.Culverts: Sidewalls of box culverts shall be carefully bonded to the base slab in accordance with (h) herein. Each wing shall be constructed as a monolith if possible. Construction joints, where unavoidable, shall be horizontal. 466404.03
2.Girders, slabs, and columns: Concrete shall be placed by beginning at the center of the span and working toward the ends. Concrete in girders shall be placed uniformly for the full length of the girder and brought up evenly in horizontal layers. The concrete floor and girders for each span of concrete through girder spans and concrete in T -beams, slab spans, and deck girders shall be placed monolithically. If the finished top surface of a concrete unit being placed is not level, care in the method of vibration, the use of low-slump concrete, or other means shall be taken to prevent downgrade movement of newly placed concrete. Special attention shall be given to sloping slabs. Concrete in columns shall be placed in one continuous operation. If cap forms are supported by falsework independent of columns or column forms or are otherwise designed so that no load is placed on columns, concrete may be placed in caps after the concrete in columns has set for at least 12 hours. Concrete shall not be placed in the superstructure until column forms have been stripped sufficiently to determine the character of the concrete in the columns.
d.Pneumatic Placement: Pneumatic concrete placement will be permitted only when authorized by the Engineer and the method is approved by the Engineer. When permitted, placement shall be in accordance with Section 412.
e.Pumping: Placing concrete by pumping will be permitted provided concrete is pumped through a conduit system that is not aluminum. Equipment shall be arranged such that vibrations that might damage freshly placed concrete will not occur. Equipment shall be thoroughly cleaned prior to use. The operation of the pump shall be such that a continuous stream of concrete without air pockets is delivered. If concrete remaining in the pipeline is to be used, it shall be ejected in such a manner that there will be no contamination of concrete or separation of ingredients.
f.Depositing Concrete Under Water: Concrete shall not be deposited in water except with the approval of the Engineer. Concrete placed in water shall be Class T3. Concrete shall be carefully placed in a compact mass in its final position by means of a tremie or another approved method and shall not be disturbed after being deposited except as specifically provided herein. Still water shall be maintained at the point of placement. A tremie shall consist of a tube having a diameter of at least 10 inches, constructed in sections having flanged couplings fitted with gaskets. The discharge end shall be closed at the start of work and entirely sealed at all times. The tremie tube shall be kept full to the bottom of the hopper. When a batch of concrete is dumped into the hopper, the flow of concrete shall be induced by slightly raising the discharge end, always keeping it in the placed concrete. Concrete seal shall be placed continuously from start to finish. Concrete shall be placed at a rate of at least one vertical foot per hour over the entire area of the seal course. The surface of concrete shall be maintained in a horizontal plane within a tolerance of 6 inches at all times during placement. The tremie shall be supported so that its discharge end is freely movable over the entire work area, or multiple tremies shall be used. Vibration shall be used only when deemed necessary by the Engineer. Supports for tremies shall permit rapid lowering of discharge ends when necessary to retard or stop the flow of concrete. The method of placing the seal shall be subject to the approval of the Engineer prior to concrete placement. 467404.03 Removal of water from cofferdams or other structures may proceed when the concrete seal has attained final set. Laitance or other unsatisfactory material shall be removed from the exposed surface by scraping and chipping with pneumatic or hand tools to an extent that will expose the aggregate for good bond with the footing to be cast upon it but not to an extent that will damage the concrete.
g.Construction Joints: Construction joints that are not detailed on the plans shall be placed as directed or approved by the Engineer. The Contractor shall use shear keys or inclined reinforcement where necessary to transmit shear or bond the two sections together. Joints shall be constructed so that feather edging does not occur. For construction joints in deck slabs, a 2 by 1 1/2-inch shear key shall be provided between mats of reinforcing steel. Construction joints against which earth fill is placed shall be protected by a heavy coat of asphalt conforming to Section 213 applied for a distance of 3 inches on each side of the joint and continuous throughout its length. In construction joints exposed to view, a waterstop conforming to Section 212 shall be inserted. The waterstop shall be placed at least 3 inches from the face of the concrete and shall extend at least 2 inches into each section of concrete. Longitudinal or transverse construction joints may be used to facilitate placing concrete in con - tinuous slab spans. Longitudinal joints shall be spaced so that each concrete placement will be at least 10 feet in width. Transverse joints shall be placed at the centerlines of piers provided they are located infrequently, permitting simultaneous longitudinal screeding of as many spans as possible. Concrete shall be placed in one continuous operation between construction joints. The volume of concrete in any one placement shall be not less than the volume of concrete in one end span.
h.Bonding Construction Joints: In preparation for joining fresh concrete to set concrete, the Contractor shall roughen the surface of the work already in place. Shavings, sawdust, and other loose and foreign material shall be removed. The surface shall be washed and scrubbed with wire brooms when necessary to remove substances that will interfere with bonding. Concrete of the preceding placement shall be thoroughly wetted prior to placement of the next unit of fresh concrete. Prior to placing adjoining concrete, the vertical face shall be cleaned and in a saturated surface moist condition. For bridge deck applications, after the concrete in the second placement has set, a V groove shall be formed along the top of the joint by abrasive blast cleaning to a depth of at least 3/8 inch and sealed with epoxy, Type EP-5, low viscosity, conforming to Section 243. Suitable keys shall be formed at the top of the upper layer of each day’ s work and at other levels where work is interrupted to bond successive courses. Keys shall be formed by inserting and subsequently removing beveled wood strips, which shall be saturated with water to induce swelling prior to insertion in fresh concrete. At the discretion of the Engineer, rough stone or steel dowels may be used in lieu of keys. Dowels shall extend an equal distance on each side of the construction joint. Prior to the inserting or driving of dowels into predrilled or preformed holes, holes shall be filled with hydraulic cement grout in the proportion of 1 part cement to 2 parts sand. The size and spacing of keys and dowels shall be determined by the Engineer.
i.Concrete Exposed to Tidal Water: Concrete structures other than box culverts subject to the action of tidal water shall not have construction joints located within a zone 5 feet above to 5 feet below the elevation of the mean tide. 468404.03 Concrete within 5 feet of the mean tide shall be cured in forms for 48 hours and allowed to dry for 5 days after forms are stripped. After drying, one coat of primer and four coats of asphalt, conforming to Section 213, shall be applied during a period of 48 hours. Each coat shall be allowed to set before the succeeding one is applied. In lieu of primer and asphalt, the coating may consist of one coat of epoxy, Type EP-3B, followed by one coat of epoxy, Type EP-3T, and shall have a total finished thickness of at least 20 mils. For precast concrete, protective coatings shall be applied in the same manner, but the seal coat shall be allowed to dry 4 days, or as long as necessary to harden, before handling. Requirements for protective coating shall also apply to inside surfaces of box culverts that are subject to the ebb and flood of tidal water. Concrete exposed to the action of ice, drift, or other forces producing shock and abrasion shall be protected by encasing that portion of the exposed surface with a special sheathing or protective ar - mor. Provision shall be made in the size of the original cofferdam for sufficient clearance to permit access to the concrete surface for the installation and effective anchorage of the sheathing.
j.Removing Formwork and Forming for and Placing Superimposed Elements: In the deter- mination for removing formwork and constructing superimposed elements, consideration shall be given to the location and character of the structure, the weather, other conditions influencing the setting of the concrete, and materials used in the mixture. Formwork shall include forms, braces, ties, guy wires, and other instruments of stabilization.
1.Formwork may be removed as follows:
a.Side forms or elements not immediately subjected to loading (for example: footings and walls or columns with height to width ratios less than 10:1 [h/w < 10:1]): 48 hours or 30 percent concrete strength (f ’c). For the purposes herein, width will be considered the narrowest portion of the element measured horizontally across its surface.
b.All other elements (for example: soffits of pile caps, bent caps and pier caps): 60 percent concrete strength (f ’c).
2.Forming for superimposed elements may be as follows:
a.Elements not immediately subjected to loading (for example: footings and walls or columns with height to width ratios less than 10:1 [h/w <10:1]): 48 hours or 30 percent concrete strength (f ’c). For the purposes herein, width will be considered the narrowest portion of the element measured horizontally across its surface.
b.All other elements: 60 percent concrete strength (f ’c).
3.Placing concrete in forms for superimposed elements shall not be done until concrete has attained 60 percent concrete strength (f ’c) except for footings, where concrete may be placed when the footing has attained 40 percent concrete strength (f ’c). The Contractor may submit calculations to show that lower strength requirements may be used but may not proceed to use these requirements before receiving written permission to do so from the Engineer. 469404.03 Concrete strength (f ’c) is the design minimum laboratory compressive strength at 28 days as specified in Table II-17 for the class of concrete designated. If the time for removing formwork and forming for or placing concrete in superimposed elements is determined by control cylinder strengths, the Contractor will be permitted to perform these operations when the control cylinder strengths reach the values previously specified. Control cylinders shall be cured under conditions that are not more favorable than the most unfavorable conditions for the portion of the concrete the cylinders represent. The Contractor shall furnish molds, labor, and materials; make sufficient test specimens; and transport specimens to the testing facility. Single-use wax paper, paper, plastic, or light-gage metal molds conforming to ASTM C470 may be used for making control cylinders. Control cylinders shall be molded under the observation of the Engineer. Tests for compressive strengths shall be performed by or under the supervision of the Engineer. The concrete strengths and time periods noted herein for removing formwork or forming for or placing concrete in superimposed elements shall not apply to the use of equipment or other live loads on the structure. Stockpiling materials or using unauthorized equipment on the structure will not be permitted until conformance to Section 404.03(m) has been attained. Methods of form removal that will overstress the concrete shall not be used. Formwork and its supports shall not be removed without the approval of the Engineer. The Contractor shall ensure that proper curing as required by the Specifications is provided immediately after form removal. Falsework shall conform to Section 404.03(b).
k.Curing Concrete: The method of curing concrete shall be subject to the approval of the Engineer prior to mixing or placing concrete. When the atmospheric temperature is above 40 degrees F in the shade, concrete surfaces that are not protected by formwork and surfaces from which forms have been removed shall be cured using approved materials applied before the sheen disappears from fresh concrete or immediately upon removal of formwork. Concrete shall be cured for 7 days, regardless of the strength obtained with control cylinders. During this 7-day curing period, a curing agent or medium shall be used. PE film used for curing shall be white except that opaque or transparent PE film may be used be - tween November 1 and April 1. When liquid membrane seal is used for curing grooved horizontal surfaces, the application rate shall be 100 to 150 square feet per gallon. The application rate for all other surfaces shall be 150 to 200 square feet per gallon. Application shall be such that an even, white, continuous membrane is produced on the concrete surface. If the atmospheric temperature falls below 40 degrees F in the shade, water curing shall be discon - tinued except when it is accomplished by flooding as specified herein. Curing shall be immediately resumed using insulated blankets or other approved methods that will retain or supply moisture and maintain the temperature at the outermost surfaces of the concrete mass above 50 degrees F for at least 72 hours immediately following concrete placement and above 40 degrees F for at least 48 additional hours. If the Contractor begins masonry concrete operations when the atmospheric temperature is below 40 degrees F in the shade, the method of cure and protection shall retain or supply moisture and maintain the temperature at the outermost surfaces of the concrete mass above 50 degrees F for at least 72 hours immediately following concrete placement and above 40 degrees F for at least 48 additional hours. 470404.03 When concrete is cured by flooding with water and the temperature is below 40 degrees F in the shade, a depth of at least 6 inches shall be maintained above the surface of the mass until concrete has attained the minimum required design compressive strength as determined by a test cylinder cured in the same water.
1.Bridge Deck Curing: Bridge deck concrete shall be moist cured with white PE sheeting with or without the use of wet burlap. The concrete shall be maintained in a moist condition by fogging after screeding and until covered with the sheeting. The concrete surface shall stay wet under the sheeting until the end of the moist-curing period. The moist-curing period shall be for at least 7 days and until 70 percent concrete strength (f ’c) is achieved. The initial temperature of the outermost surfaces of the concrete mass shall be above 50 degrees F for at least 72 hours and above 40 degrees F until the completion of the moist-curing period. When the burlap and sheeting are removed, white pigmented curing compound shall be applied at the rate of 100 to 150 square feet per gallon while the surface of the concrete deck is damp and free of standing water. Bridge deck overlay concrete shall be cured in accordance with Section 425.
l.Protecting Concrete: Protection of concrete shall begin immediately following concrete placement in the formwork and shall continue without interruption throughout the curing period.
1.Weather: The Contractor shall schedule the placement of structural concrete so that the date and hour decided upon reflect consideration of weather conditions. Concrete shall be protected from rain. Concrete shall not be placed against surfaces whose temperature is below 40 degrees F. Concrete shall be protected from freezing by approved coverings and, when necessary, heating the surrounding air in such a manner that the concrete will not dry. Protection shall be provided to prevent rapid drying of concrete as a result of low humidity, high wind, higher concrete temperatures than atmospheric temperatures, or combinations thereof. The Contractor shall perform evaporation rate testing for bridge deck placements and concrete overlays. Immediately after screeding and until the application of plastic sheeting and/or wet burlap, no surface of the freshly mixed concrete shall be allowed to dry. Fogging with pressure sprayers acceptable to the Engineer and sufficient to maintain a moist surface will be required. The protective measures taken shall be sufficient to maintain an evaporation rate at or below 0.10 pound per square foot per hour for normal concrete bridge deck placements or 0.05 pound per square foot per hour for concrete overlays over the exposed surface of the concrete. Other preventative measures described in ACI 308 can be used in addition to fogging. Evaporation retardant films may be applied in a fine mist immediately after screeding to ensure that the surface remains wet until covered. If such materials are used, there shall be no disturbance of the concrete surface after placement of the retardant film and such film shall not be intermixed with the surface mortar. If plas - tic shrinkage cracking occurs due to the Contractor’ s negligence or failure to comply with specification requirements, the Engineer may direct the Contractor to make repairs by epoxy injections, concrete removal and replacement, or other methods approved by the Engineer at no additional cost to the Department.
2.Construction activities: Care shall be taken to avoid damage to concrete from vibration created by blasting and pile driving operations, movement of equipment in the vicinity of the structure, or disturbance of formwork or protruding reinforcement. 471404.04 Concrete shall be protected from the heat of an open fire. A watchperson shall be provided at the structure throughout any period in which open-flame heaters are operated in the vicinity of the concrete. After concrete in finished surfaces has begun to set, it shall not be walked on or otherwise disturbed for at least 24 hours except as provided for in (j) herein.
3.Silicone treatment: When unpainted weathering steel is used in a structure and no other concrete waterproofing surface finish is specified, the Contractor shall apply a 5 percent solids, solvent-based, clear, water-repellent silicone treatment in two coats to the surface of the concrete substructure on exposed concrete surfaces below and including the bridge seats, within the limits of vertical planes parallel to and 2 feet outside the extreme edges of exterior beams or girders. The first coat shall be applied at the rate of 60 to 70 square feet of surface area per gallon of treatment solution, and the second coat at the rate of 90 to 110 square feet per gallon. If the treatment is applied by spraying, the nozzle shall not be held further than 24 inches from the surface being treated. The treatment shall be applied after cleaning of exposed substructure concrete surfaces and before any structural steel is erected.
m.Opening to Traffic: Structures shall not be opened to traffic, including construction traffic, or used for storing materials before the concrete has attained the 28-day minimum design compressive strength as specified in Table II-17. 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 traffic is to be permitted on a partially completed slab span, falsework shall remain in place in accordance with the strength requirements specified herein. Other structures supported on falsework from the ground shall not be opened to traffic until falsework is removed.
404.04 Bridge Deck Construction
Fogging or misting devices attached to the screed shall not be permitted. Water shall not be applied to the concrete surface at any time during the finishing. Fogging or misting to increase the relative humidity is recommended. When the longitudinal screed is used, the overall length shall be such as to screed independently support - ed spans up to and including 80 feet. The length of the screed shall be not less than the full length of the span for spans less than 80 feet. When using the longitudinal screed on independently supported spans exceeding 80 feet in length with a screed length less than the full length of the span, the center half of the span shall be completed first. Bulkheads or other substantial supports for the screed shall be placed over abutments and piers and at the terminal point of placements within the span. The surface of a previously placed section shall not be used as a bearing area for the screed track until control cylinders have attained a strength of at least 50 percent of f ’c as specified in Table II-17. When a transverse screed is used, the screed shall be of sufficient size to finish the full width of the deck between curbs or parapets unless a longitudinal joint in the deck is specified, in which case the portion on either side of the joint shall be placed and finished separately. Wheels of the screed shall bear on temporary rails supported on and directly above the main structural units or on form supports. With continuous spans, form supports shall be fully supported by the principal structural units supporting the deck. Rails shall be sufficiently rigid and strong to permit the screed to finish the surface of the deck within specified requirements. If rails are placed within the roadway area, they shall be elevated a sufficient distance above the deck to permit simultaneous finishing by hand of any portion not finished 472404.04 by the screed. Rail supports extending above the roadway surface shall be fabricated and installed in a manner to permit their removal to at least 2 inches below the top surface of the deck slab. Where rail supports are placed in that portion of the deck under curbs or parapets, supports shall be placed so that they will be at least 2 inches from the face of the curb, parapet walls, or outside edge of the slab. Prior to placing the concrete, the Contractor shall move the screed over the deck surface with blocks attached to the bottom of the screed to identify any areas where the minimum concrete cover is not likely to be obtained. The Contractor shall make adjustments in the screed placement to insure the minimum concrete cover will be obtained when the concrete is placed. An approved positive means of permitting access to the surface of the bridge shall be provided for operations requiring access to the deck surface after passing of the screed. The means of access shall not make contact with the deck surface. Concrete for the entire span or section to be placed shall remain workable until the entire operation of placing, screeding, patching, rescreeding, finishing, and testing is completed. Excess water or soupy material collected by a screeding operation shall be immediately removed from the deck and properly disposed of. If the areas of bridge decks not accessible by screed require alternate methods of finishing, the Contractor shall take care not to over finish the surface. The Contractor may float the surface to achieve the required grades, but shall not make excessive use of trowels. The concrete in the deck of a continuous beam or girder span shall be placed in accordance with the Engineer approved placement schedule. Any deviation from the approved placement schedule must be approved in writing by the Engineer after consultation with the District Structure and Bridge Engineer. After the initial placement has been made in any one group of continuous spans, no further placement shall be made until previously placed concrete in the deck of that group has been in place for at least 3 days or until the cylinder strength is at least 0.4 f ‘c. The deck surface shall be tested with a 10-foot straightedge and rescreeded as many times as is necessary to ensure a smooth riding surface. The straightedge shall be held in successive positions at the edges and quarter points and on the centerline, parallel thereto and in contact with the surface. Advancement along the deck shall be in successive stages of not more than the length of the straightedge. The surface shall also be checked transversely at the ends, quarter points, and center of the span. Areas showing high spots or depressions of more than 1/8 inch in 10 feet in the longitudinal direction and 1/4 inch in 10 feet in the transverse direction shall be struck off or filled with freshly mixed concrete. The surface across joints shall conform to the requirements for smoothness as described herein.
a.Cover Depth Survey The Contractor shall perform a Cover Depth Survey for all concrete decks to determine the acceptability of the as-constructed concrete cover. The Cover Depth Survey shall be divided into lots. The acceptability of as-constructed concrete cover on the top of bridge decks shall be determined on a lot-by-lot basis. The Contractor shall divide and mark bridge decks into lots of approximately equal size but no greater than 1,500 square feet in area. Lots shall extend from curb to curb for decks less than 60 feet wide and shall extend to the centerline of the deck for decks equal to or greater than 60 feet wide. At least 10 cover depth measurements shall be taken per lot. The locations for cover depth measure - ments shall be temporarily marked and mapped so that their locations may be tracked and verified 473404.04 on subsequent dates after initial measurements have been taken. Locations for measurements shall be laid out in an equally distributed rectilinear pattern and shall be spaced no more than 20 feet apart transversely and 15 feet apart longitudinally. The equipment and procedures for conducting the Cover Depth Survey shall be submitted to the Engineer for review and approval. Equipment must be capable of measuring cover depth to an accuracy of 1/8 inch. Procedures shall include a sketch of the lot dimensions, the division lines between lots and the number and locations of measurements proposed per lot. For each cover depth measurement, the depth of cover will be determined to the outermost reinforcing steel mat. Measurements shall be recorded to the nearest 1/8 inch. Cover depths shall be measured by individuals trained in the use of the equipment and shall be conducted and verified in the presence of the Engineer. The Contractor shall calculate the mean of the cover depth measurements for each lot to two decimal places. The depth of cover will be deemed acceptable for any lot if the average depth of cover is within 1/2 inch of the clear cover required by the plans or specifications and at least 90 percent of the cover measurements within the lot are within .80 inch of the required cover. These requirements shall apply to average cover depths that are greater than or less than the established limits, so that lots with either excessive or inadequate average cover depths not meeting the limits above shall be deemed unacceptable. The Contractor shall submit the results of the Cover Depth Survey to the Engineer. The temporary marks for the cover depth measurements shall remain visible for at least 3 days after receipt of the Cover Depth Survey but shall be removed in a manner acceptable to the Engineer prior to the bridge being opened to vehicular traffic. If any lot on a concrete bridge deck does not meet the minimum cover depth requirements herein the Contractor shall install an epoxy concrete overlay on the insufficient portion of the lot in accordance with Section 431 at no additional cost to the Department. Repair area shall include the insufficient lot or portion thereof and shall extend from curb to nearest curb.
b.Bridge Deck Crack Repair Concrete bridge decks that exhibit any shrinkage cracks equal to or greater than 0.01 inch in width within 30 days of the date of concrete placement shall be repaired by the Contractor. The Contractor shall repair cracks using Type A, Type B or Type D crack repair methods in accordance with Section 412. The cracks shall be filled at the Contractor’ s expense prior to project acceptance. Cracks not identified as requiring repair within 30 days shall be repaired as directed by the Engineer or by one of the following methods as described in Section 412.03 (b) 5: • Crack Repair Type A - V grooving • Crack Repair Type B - Epoxy injection • Crack Repair Type D - Sealing Linear Cracks In Concrete Decks And Overlays Using Epoxy And Carbon Fiber Mesh The cost of repairing cracks not identified as requiring repair within 30 days from completion of casting the segment under consideration shall be paid for at the contract unit price for Crack Repair, Type( ) in accordance with Section 412.04. 474404.04 Bridge decks shall not be recessed, cut, or otherwise permanently altered to facilitate the installation of pavement marking devices. Snow-plowable raised pavement markers or any marking requiring physical modification to the surface of the bridge deck shall not be installed on existing or new concrete bridge decks. When pavement markers are required on concrete bridge decks, the Contractor shall install raised pavement markers conforming to Section 704, which shall be bonded to the surface of the deck using an adhesive in accordance with the manufacturer’ s recommendations.
404.05 Expansion and Fixed Joints
a.Open Joints: Open joints shall be constructed by inserting and subsequently removing casting templates composed of wood strips, metal plates, or other approved material. Insertion and removal of the template shall be accomplished without chipping or breaking the corners of the concrete. Edges of concrete adjacent to joints shall be finished to a radius of approximately 1/8 inch or as shown on the plans.
b.Filled Joints: Materials for filled joints shall conform to the plans or other Contract requirements. Edges of concrete adjacent to joints shall be finished to a radius of approximately 1/4 inch or as shown on the plans. When expanded rubber, PVC, or PE filler is used, it shall be attached to the first-placed side of the joint with an approved adhesive and the concrete on the other side shall then be placed against the filler. Care shall be taken not to displace or compress the filler. Other types of premolded fillers shall be similarly placed but need not be attached by an adhesive. Finished cast joints shall be free from cracked and spalled areas. The faces of joints shall be free from foreign matter, curing compounds, oil, grease, and dirt. Joint faces shall be sandblasted and the joint blown out with oil-free and water-free compressed air just prior to application of primer or sealer.
c.Steel Joints: Plates, angles, or other structural shapes shall be fabricated to conform to the section of the concrete floor. Fabrication and painting of steel joints shall conform to Section 407 and Section 411. Care shall be taken to ensure that the surface in the finished plane is true and free from warping. Positive methods shall be employed in placing expansion joints to keep them in the correct position during concrete placement so that the opening at the expansion joint shall be that designated on the plans at normal temperature. Care shall be taken to avoid impairing the clearance in any manner. Normal temperature shall be considered as 60 degrees F , and correction to this temperature shall be computed using a coefficient of expansion of 0.0000065 per foot per degree F .
d.Waterstops: Metal waterstops shall be spliced, welded, or soldered to form continuous, watertight joints. Nonmetal waterstops shall be furnished full length for each straight portion of the joint without field splices. Manufacturer’ s shop splices shall be fully vulcanized. Field splices for neoprene waterstops shall be vulcanized; mechanical using stainless steel parts; or made with a splicing union of the same stock as the waterstop. Finished splices shall have a full-size tensile strength of 100 pounds per inch of width. 475Field splices for PVC waterstops shall be made by heat sealing adjacent surfaces in accordance with the manufacturer’ s recommendations. A thermostatically controlled electric source of heat shall be used to make splices. The heat shall be sufficient to melt but not char the material. When being installed, waterstops shall be cut and spliced at changes in direction as may be necessary to avoid buckling or distorting the web or flange. If waterstops are out of position or shape after concrete is placed, the surrounding concrete shall be removed to the proper dimensions, the waterstop reset if possible, and the concrete replaced, all at the Contractor’ s expense. If the waterstop is damaged to the extent it cannot be reset, it shall be replaced at the Contractor’ s expense.
404.06 Bridge Seat Bearing Areas
Bridge seat bearing areas shall be finished plane and level and shall not deviate more than 1/16 inch from plane or more than 1/32 inch per foot from level or from the slope specified on the plans. These limits of tolerance do not necessarily represent fully acceptable construction but are the limits at which construction may become unacceptable. In general, workmanship on bearing areas shall be at a level of quality that will be well within the tolerance limits. Bearing area roughness for elastomeric pads shall conform to Section 408.03(g). Bearing areas shall be cleaned and tested for planeness and levelness prior to placement of bearing pads or preparation for bearing plates. Preparation of bearing areas for placing bearing plates and setting anchor bolts shall be in accordance with Section 408.03(g) and (h).
404.07 Finishing Concrete Surfaces
Following replacement or satisfactory repair of defective concrete, surface defects produced by form ties, honeycombing, spalls, or broken corners or edges shall be cleaned, wetted, filled with a mortar conforming to Section 218, and troweled or struck off flush with the surrounding surface. If the surface cannot be repaired immediately following removal of forms or before the concrete surface has become dry, the surface shall be kept wet for 1 to 3 hours, as directed by the Engineer, prior to application of mortar. Repaired areas shall be cured in accordance with Section 404.03(k). The formed face of the following concrete items shall be given a Class 1 finish: (1) bridge items: wheel guards, the inside and outside faces of parapet walls, and concrete posts and rails; and (2) other items: curbs, raised medians, steps, and retaining walls that lie within 30 feet of the edge of the pavement.
a.Class 1, Ordinary Surface Finish: Following removal of forms, fins and irregular projections shall be removed from exposed surfaces and surfaces to be waterproofed. Immediately following removal of forms, surfaces that contain cavities having a diameter or depth greater than 1/4 inch shall be cleaned, wetted, filled with a mortar conforming to Section 218, and rubbed with burlap. If the surface cannot be finished immediately following removal of forms or before the concrete surface has become dry, the surface shall be kept wet for 1 to 3 hours, as directed by the Engineer, prior to application of mortar. The finished surface shall be cured in accordance with Section 404.03(k).404.07 476Construction and expansion joints in the completed work shall be left free from mortar and concrete. Joint filler shall be left exposed for its full length.
b.Class 2, Rubbed Finish: Rubbing of concrete shall be started immediately after forms are removed. Immediately before this work, concrete shall be kept wet for at least 3 hours. Sufficient time shall elapse before wetting to allow mortar used in the pointing of rod holes and defects to set thorough - ly. Surfaces to be finished shall be rubbed with a medium-coarse carborundum stone with a small amount of mortar on its face. Mortar shall be composed of cement and fine aggregate mixed in the proportions used in the concrete being finished. Rubbing shall be continued until form marks, projections, and irregularities are removed; voids are filled; and a uniform surface is obtained. Paste shall be left in place. The final finish shall be obtained by rubbing with a fine carborundum stone and water. Rubbing shall be continued until the entire surface has a smooth texture and uniform color. After final rubbing is completed and the surface has dried, the surface shall be rubbed with burlap and left free from unsound patches, paste, powder, and objectionable marks.
c.Class 3, Tooled Finish: This finish shall be produced by the use of a bush hammer, pick, crandall, or other approved tool. Tooling shall not be done until concrete has set for at least 14 days or longer as may be necessary to prevent aggregate particles from being picked out of the surface. The finished surface shall show a grouping of broken aggregate particles in a matrix of mortar, with each aggregate particle in slight relief.
d.Class 4, Sandblasted Finish: The thoroughly cured concrete surface shall be sandblasted to produce an even, fine-grained surface in which mortar has been cut away, leaving the aggregate exposed.
e.Class 5, Wire Brushed or Scrubbed Finish: This finish shall be produced by scrubbing the surface of the plastic concrete with stiff wire or fiber brushes using a solution of muriatic acid in the proportion of 1 part acid to 4 parts water. As soon as forms are removed, and while concrete is comparatively plastic, the surface shall be scrubbed thoroughly and evenly until the cement film or surface is removed and aggregate particles are exposed, leaving an even, pebbled texture presenting an appearance grading from that of fine granite to coarse conglomerate, depending on the size and grading of the aggregate used. As soon as scrubbing has progressed sufficiently to produce the texture desired, the entire surface shall be thoroughly washed with water to which sufficient ammonia has been added to neutralize and remove all traces of acid.
f.Class 6, Bridge Deck Finish: Methods, procedures, and equipment shall conform to Section 404.03, shall not result in segregating ingredients of the concrete; and shall ensure a smooth riding surface. Hydraulic cement concrete bridge deck surfaces shall be textured with uniformly pronounced grooves sawed transversely to the centerline. After final screeding of the deck, a multi-ply damp fabric shall be dragged over the deck surface to provide a gritty texture. The deck concrete shall not be grooved until it has reached an age of 14 days or 85 percent of the 28-day minimum design compressive strength. Grooves shall be sawed approximately 3/16 ± 1/16 inch in depth and 1/8 inch in width (nominal) on 3/4-inch (nominal) centers. Grooves shall terminate 12 ± 1 inches from the parapet wall or curb line. Grooves shall not be sawed closer than 2 or further than 3 inches from the edge of any joint. When the width of the cutting head on the grooving machine is such that grooves cannot be practically sawed to within the required tolerance for a skewed transverse joint, grooving shall not be closer than 2 inches or more than 36 inches from the edge of the joint. On curved decks, each pass of the grooving machine shall begin on the side of the deck having the smaller radius and the nominal spacing of grooves at the starting point shall be 3/4 inch on center.404.07 477Bridge decks should be grooved prior to opening to traffic. However, the Contractor will be permitted to delay grooving up to 6 months. The Contractor shall provide the Engineer with a plan for traffic control when working under traffic. If a single pass of the grooving machine cannot be made across the width of the bridge, the mating ends of subsequent passes shall not overlap previous grooves or leave more than 1 inch of surface ungrooved. After concrete has set and prior to placement of other slabs, the deck surface will be tested by the Engineer. Areas showing high spots or depressions of more than the specified tolerances will be marked as failing to conform to smoothness requirements. Levels may also be run over the surface to determine if there is any deviation from grade and cross section. Decks that do not conform to thickness and surface smoothness requirements will not be accepted until deficiencies have been corrected as directed by the Engineer. Sections that cannot be satisfactorily corrected shall be removed and replaced at the Contractor’ s expense. Bridge decks that are to receive an asphalt concrete overlay of 1 inch or more in thickness shall be finished to a tolerance of 1/4 inch in 10 feet in both longitudinal and transverse directions except at expansion joints, where the finished tolerance shall be 1/8 inch in 10 feet.
g.Class 7, Sidewalk Finish: After concrete has been placed, it shall be consolidated and the surface struck off with a strike board and floated with wooden or cork floats. Light metal marking rollers may be used if desired after the initial set. An edging tool shall be used on edges and at joints. The surface shall not vary more than 1/4 inch under a 10-foot straightedge and shall have a granular texture that will not be slick when wet.
404.08 Measurement and Payment
Concrete will be measured in cubic yards within the neat lines of the structure as shown on the plans and will be paid for at the contract unit price per cubic yard for the Class designated. Deductions will not be made for chamfers 1 inch or less in width or for grooves less than 1 inch in depth. The volume of reinforcing steel or any other material or internal voids within the concrete will be deducted. The volume of bridge deck slab concrete allowed for payment will be computed using the actual thickness of the slab, not to exceed the plan thickness plus 1/2 inch, for the area between faces of sidewalks, curb lines, railings, or parapets. The area beneath sidewalks, curbs, railings, or parapets will be based on the plan thickness. Unless designated as separate pay items, this price shall include waterstops, waterproofing, damp-proofing, anchor bolts, drain assemblies, silicone treatment, protective coating for concrete exposed to tidal waters, and trial batches. If corrugated metal bridge deck forms are used in lieu of removable forms, the price for concrete shall include furnishing and placing metal forms, additional concrete required to fill corrugations, work neces - sary to facilitate inspection of the underside of the deck, repairing deficiencies, and strengthening beams or girders to maintain the design live-load rating of the bridge. Bridge-deck grooving will be measured in square yards of deck surface area from the faces of parapets, sidewalks, or curb lines and will be paid for at the contract unit price per square yard. No deduction will be made for drainage items and joints.404.08 478Cover Depth Survey will be measured in square yards and will be paid for at the contract unit price per square yard. This price shall include furnishing all personnel and equipment required to perform, document, and deliver the survey to the Engineer. Payment will be made under: ————————————————————— Pay Item Pay Unit————————————————————— Concrete (Class) item Cubic yard Bridge-deck grooving Square yard Cover Depth Survey Square yard————————————————————— SECTION 405—PRESTRESSED CONCRETE
405.01 Description
These specifications cover the use of prestressed or post-tensioned hydraulic cement concrete when called for on the plans.
405.02 Materials
a.Concrete shall conform to Section 217, Class A5, with the following exceptions: Each project, and bridge unit within a project (if multiple bridges are part of the same project) shall have an approved mix design that accounts for the closest bar spacing in that girder or other element supplied. The maximum top size of aggregate shall not exceed one-fifth of the narrowest dimension of the concrete formwork, three-quarters of the narrowest clear spacing between reinforcing steel bars or bundles of bars and/or strands, or three-quarters of the minimum clear cover over the steel reinforcement. The concrete mix proportions shall be submitted to the Engineer for review prior to production. No. 57, 7, 68, or 78 aggregate may be used for coarse aggregate subject to the limitations for the top size of coarse aggregate above.
b.Concrete admixtures shall conform to Section 215.
c.Epoxy-resin compounds shall conform to Section 243.
d.Steel reinforcement and prestressed tendons shall conform to Section 223.
e.Structural steel shall conform to Section 226.
f.Bedding materials and bearing pads shall conform to Section 237 and Section 408.
g.Waterproofing shall conform to Section 416.
h.Hydraulic cement mortar and grout shall conform to Section 218.
i.Fully or partially embedded steel attachments to the prestressed concrete members shall be galvanized in accordance with Section 233.404.08
Source: Virginia Road and Bridge Specifications, 2020 Edition. Pages 487–505 of 1,065.