exhibit âeâ itb #12-04 - City of Fernandina Beach
EXHIBIT “E” ITB #12-04 SCOPE OF WORK & SPECIFICATIONS FOR REHABILITATION OF CONCRETE STRUCTURAL BEAMS A. General The project consists of the repair of damaged concrete beams and double tees beneath two (2) waterfront structures at the Fernandina Harbor Marina. Beams and double tees beneath a portion of the waterfront restaurant, lying within the area shown on Exhibit “F”, shall be repaired. Beams and deck beneath the Marina Dock office shall also be repaired. Repair work shall be performed using the specifications contained herein and shall follow the recommendations described in the following documents: a) Inspection Report prepared by the Haskell Company, dated January 27, 2011 b) Inspection Report prepared by ATM, dated March 2011 c) Inspection Report prepared by the Haskell Company, dated November 2, 1011 B. Mobilization Work includes bonds, insurance, bonds, permits, temporary facilities, job site safety, watercraft & barges, scaffolding, booms & floats, testing & laboratory services, protection of existing buildings, utility lines, docks & vessels and final cleanup. C. Restrictions on work The Contractor is alerted to the fact that the existing concrete beams are submerged during each high tide, therefore making the work zone inaccessible for several hours each day. The contractor shall account for these natural conditions and no additional payment will be made for delays or damage to completed work caused by the fluctuating water levels. D. Measurement & Payment The work shall be paid for under the unit prices and measurements shown on the Bid Form, Exhibit “A”, except that mobilization shall be paid for as a fixed lump sum. Quantities shown on the Bid Form are preliminary. More accurate quantities shall be determined in the field prior to issuance of the Notice to Proceed. The City and Contractor shall perform a field inspection to delineate the actual areas of repairs to be undertaken. A final, post-construction measurement will be performed in the event the Contractor encounters additional damaged concrete during performance of the rehabilitation work.
City of Fernandina Beach
April 2012 Page E-1 of 4
E. Removal and replacement of damaged concrete and reinforcing steel Work includes removal and disposal of all loose or damaged concrete by mechanical hand-tools and water-blasting, followed by high-pressure (10,000-15,000 psi) hydro-blasting. Remove all heavily corroded reinforcing bars and wire. (FDOT Specification Section 923 & 930). Install temporary supports where necessary to support short beam sections during repair. Saw-cut the entire perimeter of all repair areas to a minimum depth of one-inch, except where shallower cuts are required to avoid cutting reinforcing steel near the surface of the concrete. Feather edge repairs will not be permitted. Obtain Engineers approval of the limits of concrete removal before proceeding to final surface preparation. Once the initial concrete is removed, use small power-driven chipping hammer, sandblasting and/or hydroblasting equipment to undercut all exposed reinforcing steel. Where damaged concrete removal exposes more than 1/3 of the rebar perimeter, the contractor shall remove additional concrete in order to expose the entire perimeter of the rebar for repair. Provide a minimum clearance of 3/4” to 1” between the exposed steel and the surrounding concrete to allow new concrete to completely surround the exposed bars. Contractor shall remove additional concrete, as deemed necessary by the Engineer, to keep the repair area to a reasonably uniform depth. Beat the remaining existing concrete with small hammers or sandblast to create a rough surface. F.
Reinforcing Steel
If corrosion has reduced the cross-sectional area of rebar to less than 75% of its original diameter, the bars should be removed and cut back to a point where good steel is encountered. All reinforcing steel removed shall be replaced. Install replacement and supplemental reinforcing bars as necessary to maintain continuous reinforcement. Lap adjacent bars at least 6 in. and tie together securely with stainless steel wire splices. Secure new reinforcement bars to prevent displacement during application of repair material. Remove all rust and scale from the remaining, exposed reinforcing steel using a wire brush, sandblast or hydroblast. Clean and dry all exposed rebar using an air blast, then immediately coat all exposed rebar with Ospho or Sika Armatec 110 EpoChem. Install new supplemental reinforcing bars using bars of same size with stainless steel wire ties. No sooner than 24 hours and no later than 72 hours following application of the acid, apply two coats of “ZincRich” rebar primer to both the existing and new rebar. Concrete grout or mortar repair material shall be placed no later than 7 days following application of the rebar primer
City of Fernandina Beach
April 2012 Page E-2 of 4
EXHIBIT “E” (cont) G. Formwork. Forms will be necessary for all overhead replacement and for most vertical surfaces to prevent slippage of replacement materials. Forms shall be lightweight and be designed for re-use in the next section of repair work. Ensure forms are securely attached and mortar-tight. Forms shall be used for epoxy-bonded concrete where necessary to confine the concrete and shape it to the required lines. Forms shall have sufficient strength to withstand the pressure resulting from placing operations, shall be maintained rigidly in position, and shall be sufficiently tight to prevent loss of mortar from the concrete H. Substrate Preparation Where saturated surface-dry (SSD) conditions are required, pre-wet the substrate for 3 to 6 hours before placing the repair materials. Achieve full SSD conditions by high-pressure water blasting 10 to 20 min. before placing the repair material. A saturated surface-dry condition is achieved when the surface remains damp when exposed to sunlight for 15 min. A SSD condition prevents old concrete from absorbing mix water from the repair material and promotes development of adequate bond strength in the repair material. Use a bonding agent for repair material unless directed otherwise. Use either a cement scrub coat or a Type V or Type VII epoxy conforming to DMS-6100, “Epoxies and Adhesives,” as the bonding agent. Follow the manufacturer’s recommendations for bonding agents if prepackaged repair materials are used. Do not use an epoxy bonding agent with rapid setting repair materials. Apply a cement scrub coat bonding agent to the saturated surface-dry substrate by scrubbing, brushing, or other approved methods immediately before placing the repair material. Apply SikaArmatex 110 Bonding agent, or approved equal, to existing concrete in accordance with the manufacturer’s recommendations. Ensure that any bonding agent used does not set or cure prematurely, creating a bond break.
I.
Repair Material Application
Place the repair material in an approved manner ensuring that the repair material is in intimate contact with the substrate and free of voids. Repair shallow cracks using SikaTop 122 Plus applied by hand. Repair using Sikacrete 211, an approved equal, or an approved epoxy bond concrete for wide or deeper repairs. Follow the manufacturer’s recommendations for mixing and placement. Place repair materials so that the original lines and surfaces of the structure are restored. Concrete grout and mortar may not be placed when the ambient temperature is less than 60°F or above 90°F. Repair with concrete mixture: SikaTop 122 Plus (hand), SikaCrete 211 Plus (poured), Phoscrete, RheoMix141 admixture, City of Fernandina Beach
April 2012 Page E-3 of 4
J.
Curing
Cure all concrete grout and mortar for a minimum of 10 days. Contractor shall maintain surface moisture by application of a light mist of water every 12 hours during the first 72 hours following placement. Remove forms in conformance with the manufacturer’s recommendations or at the end of the curing period. K.
Defective Work
After curing, the Engineer shall determine the limits of any newly placed concrete that are defective or concrete which de-bonded after placement. Those areas shall be removed and repaired at the Contractor’s expense. L. Sacrificial Cathodic Protection (Additive Alternate One) Install a zinc cathodic protection system on the horizontal concrete perimeter beams. References: FDOT Maintenance Handbook Section 5.3.5.A M. Final Sealing Seal the top, side and bottom surfaces of the horizontal concrete perimeter beams and tees with penetrant sealer per FDOT Specification Section 413.
City of Fernandina Beach
April 2012 Page E-4 of 4
City of Fernandina Beach
April 2012 Page E-1 of 4
E. Removal and replacement of damaged concrete and reinforcing steel Work includes removal and disposal of all loose or damaged concrete by mechanical hand-tools and water-blasting, followed by high-pressure (10,000-15,000 psi) hydro-blasting. Remove all heavily corroded reinforcing bars and wire. (FDOT Specification Section 923 & 930). Install temporary supports where necessary to support short beam sections during repair. Saw-cut the entire perimeter of all repair areas to a minimum depth of one-inch, except where shallower cuts are required to avoid cutting reinforcing steel near the surface of the concrete. Feather edge repairs will not be permitted. Obtain Engineers approval of the limits of concrete removal before proceeding to final surface preparation. Once the initial concrete is removed, use small power-driven chipping hammer, sandblasting and/or hydroblasting equipment to undercut all exposed reinforcing steel. Where damaged concrete removal exposes more than 1/3 of the rebar perimeter, the contractor shall remove additional concrete in order to expose the entire perimeter of the rebar for repair. Provide a minimum clearance of 3/4” to 1” between the exposed steel and the surrounding concrete to allow new concrete to completely surround the exposed bars. Contractor shall remove additional concrete, as deemed necessary by the Engineer, to keep the repair area to a reasonably uniform depth. Beat the remaining existing concrete with small hammers or sandblast to create a rough surface. F.
Reinforcing Steel
If corrosion has reduced the cross-sectional area of rebar to less than 75% of its original diameter, the bars should be removed and cut back to a point where good steel is encountered. All reinforcing steel removed shall be replaced. Install replacement and supplemental reinforcing bars as necessary to maintain continuous reinforcement. Lap adjacent bars at least 6 in. and tie together securely with stainless steel wire splices. Secure new reinforcement bars to prevent displacement during application of repair material. Remove all rust and scale from the remaining, exposed reinforcing steel using a wire brush, sandblast or hydroblast. Clean and dry all exposed rebar using an air blast, then immediately coat all exposed rebar with Ospho or Sika Armatec 110 EpoChem. Install new supplemental reinforcing bars using bars of same size with stainless steel wire ties. No sooner than 24 hours and no later than 72 hours following application of the acid, apply two coats of “ZincRich” rebar primer to both the existing and new rebar. Concrete grout or mortar repair material shall be placed no later than 7 days following application of the rebar primer
City of Fernandina Beach
April 2012 Page E-2 of 4
EXHIBIT “E” (cont) G. Formwork. Forms will be necessary for all overhead replacement and for most vertical surfaces to prevent slippage of replacement materials. Forms shall be lightweight and be designed for re-use in the next section of repair work. Ensure forms are securely attached and mortar-tight. Forms shall be used for epoxy-bonded concrete where necessary to confine the concrete and shape it to the required lines. Forms shall have sufficient strength to withstand the pressure resulting from placing operations, shall be maintained rigidly in position, and shall be sufficiently tight to prevent loss of mortar from the concrete H. Substrate Preparation Where saturated surface-dry (SSD) conditions are required, pre-wet the substrate for 3 to 6 hours before placing the repair materials. Achieve full SSD conditions by high-pressure water blasting 10 to 20 min. before placing the repair material. A saturated surface-dry condition is achieved when the surface remains damp when exposed to sunlight for 15 min. A SSD condition prevents old concrete from absorbing mix water from the repair material and promotes development of adequate bond strength in the repair material. Use a bonding agent for repair material unless directed otherwise. Use either a cement scrub coat or a Type V or Type VII epoxy conforming to DMS-6100, “Epoxies and Adhesives,” as the bonding agent. Follow the manufacturer’s recommendations for bonding agents if prepackaged repair materials are used. Do not use an epoxy bonding agent with rapid setting repair materials. Apply a cement scrub coat bonding agent to the saturated surface-dry substrate by scrubbing, brushing, or other approved methods immediately before placing the repair material. Apply SikaArmatex 110 Bonding agent, or approved equal, to existing concrete in accordance with the manufacturer’s recommendations. Ensure that any bonding agent used does not set or cure prematurely, creating a bond break.
I.
Repair Material Application
Place the repair material in an approved manner ensuring that the repair material is in intimate contact with the substrate and free of voids. Repair shallow cracks using SikaTop 122 Plus applied by hand. Repair using Sikacrete 211, an approved equal, or an approved epoxy bond concrete for wide or deeper repairs. Follow the manufacturer’s recommendations for mixing and placement. Place repair materials so that the original lines and surfaces of the structure are restored. Concrete grout and mortar may not be placed when the ambient temperature is less than 60°F or above 90°F. Repair with concrete mixture: SikaTop 122 Plus (hand), SikaCrete 211 Plus (poured), Phoscrete, RheoMix141 admixture, City of Fernandina Beach
April 2012 Page E-3 of 4
J.
Curing
Cure all concrete grout and mortar for a minimum of 10 days. Contractor shall maintain surface moisture by application of a light mist of water every 12 hours during the first 72 hours following placement. Remove forms in conformance with the manufacturer’s recommendations or at the end of the curing period. K.
Defective Work
After curing, the Engineer shall determine the limits of any newly placed concrete that are defective or concrete which de-bonded after placement. Those areas shall be removed and repaired at the Contractor’s expense. L. Sacrificial Cathodic Protection (Additive Alternate One) Install a zinc cathodic protection system on the horizontal concrete perimeter beams. References: FDOT Maintenance Handbook Section 5.3.5.A M. Final Sealing Seal the top, side and bottom surfaces of the horizontal concrete perimeter beams and tees with penetrant sealer per FDOT Specification Section 413.
City of Fernandina Beach
April 2012 Page E-4 of 4
