CONSTRUCTION SPECIFICATION FOR PRECAST REINFORCED CONCRETE BOX CULVERTS AND BOX SEWERS

Transcription

1 ONTARIO PROVINCIAL STANDARD SPECIFICATION METRIC OPSS 422 MAY 1993 CONSTRUCTION SPECIFICATION FOR PRECAST REINFORCED CONCRETE BOX CULVERTS AND BOX SEWERS SCOPE REFERENCES DEFINITIONS TABLE OF CONTENTS SUBMISSION AND DESIGN REQUIREMENTS MATERIALS Concrete.02 Granular Materials.03 Fine Aggregates for Levelling Course.04 Precast Reinforced Concrete Box Units.05 Clay Seal.06 Steel Reinforcement.07 Mortar.08 Grout.09 Geotextile Not Used CONSTRUCTION Selection of Precast Reinforced Concrete Box Units.02 Excavation.03 Shoring and Bracing.04 Dewatering.05 Protection Schemes.06 Bedding.07 Installing Precast Concrete Box Units for Box Culverts and Box Sewers Box Units.02 Geotextile at Joints.03 Mortar.04 Lift Holes Concrete Appurtenances.09 Backfill.10 Clay Seal Page 1 Rev. Date: 05/1993 OPSS 422

2 Not Used MEASUREMENT FOR PAYMENT Actual Measurement Precast Concrete Box Culverts and Box Sewers.02 Granular.03 Rock Excavation Plan Quantity Measurement Precast Concrete Box Culvert or Sewer.02 Rock Excavation BASIS OF PAYMENT Precast Concrete Box Culvert - Item Precast Concrete Box Sewer - Item.02 Granular.03 Steel Reinforcement in Concrete Appurtenances.04 Concrete in Appurtenances.05 Rock Excavation for Box Culverts and Box Sewers.06 Clay Seal.07 Swamp Excavation SCOPE This specification covers the requirements for the installation of precast reinforced concrete box culverts and box storm sewers in open cut and includes the requirements for excavation, bedding, and backfilling operations REFERENCES This specification refers to the following standards, specifications or publications: Ontario Provincial Standard Specifications, General: OPSS 102 Weighing of Materials Ontario Provincial Standard Specifications, Construction: OPSS 209 OPSS 501 OPSS 517 OPSS 538 OPSS 539 OPSS 902 OPSS 904 OPSS 905 Embankments Over Swamps Compacting Dewatering Shoring and Bracing Protection Schemes Excavating and Backfilling - Structures Concrete Structures Steel Reinforcement for Concrete Page 2 Rev. Date: 05/1993 OPSS 422

3 Ontario Provincial Standard Specifications, Material: OPSS 1002 OPSS 1004 OPSS 1010 OPSS 1205 OPSS 1301 OPSS 1302 OPSS 1350 OPSS 1440 OPSS 1821 OPSS 1860 Aggregates - Concrete Aggregates - Miscellaneous Aggregates - Granular A, B, M and Select Subgrade Material Clay Seal Hydraulic Cementing Materials Water Concrete - Materials and Production Steel Reinforcement for Concrete Precast Reinforced Concrete Box Culverts and Box Sewers Geotextile DEFINITIONS For the purpose of this specification the following definitions apply: Bedding: means the material used to support the bottom of the box unit. Box Culvert or Box Sewer: means a culvert or sewer constructed of precast, reinforced concrete box units rectangular in cross-section. Concrete Appurtenances: means head walls, cut-off walls, aprons, collars and any other concrete fixtures associated with the box culverts and box sewers excluding concrete bedding or concrete structures covered elsewhere in the Contract and specified as such. Cover Material: means the protective layer placed around the box unit to prevent damage to the box unit. Excavation, Earth and Rock: means the excavation classified as earth and rock in conformance to OPSS 902. Excavation, Swamp: means the excavation of material defined as Swamp Material in OPSS 209. Granular Backfill: means granular fill material used beyond the limits of the bedding and cover material below the subgrade elevation, including frost tapers. Native Backfill: means the material which was removed to form an excavation and which is then returned to the same excavation as backfill material. Native Material: means the material which was removed to form an excavation and which is now accepted by the Contract Administrator for return to the same or other excavation as backfill material SUBMISSION AND DESIGN REQUIREMENTS Six copies of the fabrication and assembly drawings including handling details shall be submitted to the Contract Administrator two weeks prior to delivery of the box units MATERIALS Concrete Concrete for appurtenances shall conform to OPSS Page 3 Rev. Date: 05/1993 OPSS 422

4 Granular Materials Granular materials shall conform to the requirements of OPSS Fine Aggregates for Levelling Course Fine aggregate for levelling courses shall conform to OPSS Precast Reinforced Concrete Box Units Precast Reinforced Concrete Box Units shall conform to OPSS Clay Seal Clay Seal material shall conform to OPSS Steel Reinforcement Steel reinforcement in concrete appurtenances shall conform to OPSS Mortar Mortar for joints shall be composed of one part normal Portland cement and two parts mortar sand wetted with only sufficient water to make the mixture plastic. The normal Portland cement shall conform to OPSS 1301, the mortar sand shall conform to OPSS 1004 and water shall conform to OPSS Grout Grout shall be non-shrink and non-staining Geotextile Geotextile shall conform to OPSS CONSTRUCTION Selection of Precast Reinforced Concrete Box Units The precast reinforced concrete box units for box culverts and box sewers shall be selected from the tables in OPSS 1821 based on the dimensions and depth of cover specified in the Contract Excavation The excavation for the installation of the box units and for constructing frost tapers and culvert end treatments shall be in conformance to OPSS 902 to the width, depths and alignments specified in the Contract. Excess materials or materials unsuitable for the contract requirements shall be managed as specified elsewhere in the Contract Shoring and Bracing Shoring and bracing shall conform to OPSS 538. Page 4 Rev. Date: 05/1993 OPSS 422

5 Dewatering Dewatering shall conform to OPSS Protection Schemes Protection schemes shall conform to OPSS Bedding Bedding shall be as specified in the Contract and constructed to provide a uniform support for the full length and width of each box unit. Bedding material shall not be placed on a frozen earth grade. Bedding materials shall be placed to the dimensions shown in the Contract. Bedding requiring compaction shall be placed in layers not exceeding 200 mm in thickness, loose measurement, and each layer shall be compacted in conformance to OPSS 501. The surface prepared to support the precast box units shall have a minimum of 75 mm thickness levelling course of Granular 'A' or Fine Aggregate Installing Precast Concrete Box Units for Box Culverts and Box Sewers Box Units Precast concrete box units for box culverts and box sewers shall be installed to the alignment and grade specified in the Contract. Box units shall not be installed on a bedding containing frozen material. End units to accommodate headwalls, cut off walls and other concrete appurtenances shall be as specified elsewhere in the Contract. The box units shall be installed to make a continuous line forming a box culvert or box sewer. The gap at joints shall not exceed 15 mm. The box units shall be placed in parallel for multiple cell installations by providing a 60 mm ± 10 mm gap filled with grout between adjacent cells. Installation shall commence at the outlet end and proceed in the upstream direction with the bell ends of the box units facing upgrade. Box units shall be installed on the prepared bed, true to the line and grade specified. The base of each box unit shall be in uniform contact with the prepared bed throughout its full length. The ends of the box units shall be joined so that there is no unevenness along the inside. Box units and joint surfaces shall be kept clean as work progresses. Water shall not be allowed to flow through the box units during installation. The excavation shall be kept dry and the box units shall not be installed in water Geotextile at Joints A 600 mm wide strip of geotextile shall be placed to form a continuous barrier centered around the exterior of all buried joints. Page 5 Rev. Date: 05/1993 OPSS 422

6 Geotextile shall be free of folds, tears and wrinkles. The geotextile shall be joined so that the material laps a minimum of 500 mm and shall be pinned together. Alternatively, the geotextile shall be joined to conform with the seam requirements of OPSS Mortar When mortared joints are specified in the Contract, all joints shall be thoroughly cleaned and wetted. Mortar shall then be applied over the joint around the inner and outer perimeter. After the mortar joint is complete the joint inside shall be wiped clean and smooth Lift Holes Lift holes shall be filled with mortar Concrete Appurtenances Concrete appurtenances shall be constructed to conform to OPSS 904 and reinforcing steel shall be placed to conform to OPSS Backfill Backfill and cover material shall be placed in layers not exceeding 200 mm in thickness loose measurement. Compaction shall conform to the requirements of OPSS 501. Backfill on each side of the box units shall be completed simultaneously. At no time shall the levels on each side differ by more than a 400 mm. Earth backfill shall be free of boulders over 150 mm, topsoil, and other deleterious material. When the Contract specifies native backfill for box culverts or box sewers the Contractor upon approval by the Contract Administrator, may substitute acceptable earth backfill material. In areas within the roadway, for a depth equal to the frost treatment, the earth backfill material shall have frost susceptible characteristics similar to the native material. The Contract Administrator will decide on the suitability of the earth backfill material which the Contractor proposes to substitute. Cover material shall be earth or granular, as specified, and free from stones exceeding 75 mm. Rock backfill will be accepted provided the installation is protected by a minimum of cover material as indicated in the Contract. Frozen materials will not be permitted as backfill or cover material. Box unit installation and backfill shall be completed prior to the start of any subbase and base course construction over the box culvert and box sewer location. Shoring and bracing shall be withdrawn and removed as the excavation is being backfilled Clay Seal When clay seal is specified the Contractor shall place the clay seal to the dimensions specified and compact it to 95% of maximum dry density. Page 6 Rev. Date: 05/1993 OPSS 422

7 MEASUREMENT FOR PAYMENT Actual Measurement Precast Concrete Box Culverts and Box Sewers Measurement of the actual length of box culvert or box sewer installed will be made in metres along the centerline of the invert of the box units Granular Granular material used for bedding, backfill, and cover material will be measured in tonnes conforming to OPSS 102. Granular will not be measured when used to fill any volume which is excavated beyond the lines specified in the Contract or used as cover material where earth cover material is acceptable Rock Excavation Rock excavation for box culverts or box sewers will be measured in cubic metres. The computation of the quantity of rock excavated will be based on the limits of the excavation required for bedding, backfill and cover material as specified in the Contract. The upper limit will be the elevation of the original rock line or the lowest elevation of all other excavation indicated in the Contract, whichever is lower. The volume of boulders in an excavation shall be determined on the basis of the three maximum rectilinear dimensions. Where boulders classified as rock, are measured for payment, only the amount actually removed shall be considered for payment and shall not exceed the calculated volume of excavation within the theoretical lines Plan Quantity Measurement Precast Concrete Box Culvert or Sewer Measurement of box culverts or box sewers is by Plan Quantity as may be revised by Adjusted Plan Quantity along the centerline of the invert of the box unit Rock Excavation Measurement for rock excavation is by Plan Quantity as may be revised by Adjusted Plan Quantity, of the volume in cubic metres in conformance to clause BASIS OF PAYMENT Precast Concrete Box Culvert - Item Precast Concrete Box Sewer - Item Payment at the contract price for the above item(s) shall be full compensation for all labour, equipment and materials to do the work. Should the earth excavation for the above items overlap excavation required for any other work under the contract, then payment shall be made in accordance with the specification for such other work as though no excavation were required for these items. Page 7 Rev. Date: 05/1993 OPSS 422

8 Granular Granular material used for bedding, backfill and cover material, and frost tapers, shall be paid for under the appropriate granular items specified in the contract Steel Reinforcement in Concrete Appurtenances Payment for the above shall conform to OPSS 905. Page 8 Rev. Date: 05/1993 OPSS 422