B511 - - OPSS 511 511.1 GENERAL 511.1.1 Rip-Rap Excavation for placing rip-rap, rock protection, and granular sheeting is part of each individual tender item. Rip-rap is a special application of rock protection. It consists of rocks, broken rocks, cobbles, stones, boulders or concrete debris placed together in a set and stable manner to a specified thickness for the protection of earth slopes and surfaces. It is used in areas where erosion is a problem or anticipated, or where the appearance of the placed rocks is an important factor. Areas of rip-rap applications may include: a) Earth slopes b) Culvert and sewer ends c) Streambeds and slopes d) Ditches with gradients 5% and greater e) Around manholes, catch basins or ditch inlets constructed in ditches or on ditch slopes. Rip-rap is commonly used in conjunction with a filter medium such as geotextile or granular sheeting. These prevent loss of fines from beneath the rip-rap and subsequent collapse of the protection scheme. In some cases, more complex layered filter systems may be required, as recommended by the geotechnical or foundation staff on the project. Rip-rap shall not be used in waterbodies if it contains concrete debris. Suitable alternatives are available. Consult with the foundation, geotechnical, and environmental staff on the project as required. 511.1.2 Rock Protection Rock protection consists of broken rocks, rocks, cobbles, boulders and/or concrete debris dumped or placed in random but stable manner. December 2018 Page 1 of 6 CDED B511
The primary use of rock protection is to protect ditches and channels from erosion, including the banks and underwater portions. Rock protection is laid to a specified depth and elevation and commonly placed in conjunction with a filter medium. In waterbodies, rock protection shall only be used as required for the purpose of scour protection for structures and shall not contain concrete debris. Suitable alternatives may be considered. 511.1.3 Granular Sheeting 511.1.4 Geotextile Granular sheeting consists of a surface layer of granular material which has to conform to a specified gradation. It is used for erosion protection and also applied in areas of ground water seepage. The decision to include "Granular Sheeting" into the contract rests with the geotechnical and foundation staff on the project. Geotextile is a synthetic fabric. The primary function of this material is: a) To separate two types of soils of different sizes and structures that would readily mix under the influence of load and water migration. b) To filter or to hold back soil particles while allowing the passage of water. c) To drain or to ensure the rapid removal of moisture without buildup of hydrostatic pressures. d) To reinforce, mainly by tensile strength of fabrics and their resistance to puncture (burst), tear and shear forces. The application of geotextile is designated by its: a) Strength class (i.e. Class I or II) b) Fabric structure (woven or non-woven) c) Equivalent opening size d) Minimum nominal thickness Geotextile may be used to act as a separator and filter between the rip-rap or rock protection and underlying material, depending on the existing soil conditions. The need for geotextiles should be assessed on a project-specific basis. Where the December 2018 Page 2 of 6 CDED B511
OPSS 511 requirements for geotextile are not appropriate, the geotextile requirements shall be specified in the Contract Drawings or by Non-Standard Special Provision. The decision to use geotextile is the responsibility of the geotechnical and foundation staff on the project. A comprehensive write-up on the use of geotextiles is contained in the MTO publications "The Geotechnical Use of Filter Fabrics in Highway Construction" Report EM-13 and Engineering Geotextiles Report EM-45. If surface conditions, on which geotextile will be placed, are such that it is not possible to place the geotextile in a reasonably level manner (undulating ground or high water level) a levelling layer of approved material should be placed to provide a satisfactory surface. Geotextile placement below water and particularly in flowing water conditions can be difficult as the geotextile and rock materials placed on top of it may become dislodged and carried downstream during periods of high flow. Where these conditions exist, consult with the geotechnical and foundation staff on the project for suitable alternatives. 511.2 REFERENCES The Geotechnical Use of Filter Fabrics in Highway Construction - MTO Report EM-13 Engineering Geotextiles, MTO Report EM-45 Structural Manual OPSS 1004 Aggregates - Miscellaneous 511.3 TENDER ITEMS Rip-Rap Rock Protection Granular Sheeting Geotextile (Variation, m², PQP) (Normal, m³, PQP) (Normal, m², PQP) (Variation, m², PQP) 511.4 SPECIFICATIONS The requirements for the above tender items are covered by OPSS 511. 511.5 SPECIAL PROVISIONS The designer should refer to Chapter "E" of this manual to review the applicable special provisions. December 2018 Page 3 of 6 CDED B511
511.6 STANDARD DRAWINGS Rip-rap treatment with Geotextile for Ditch Inlet Manholes and for Sewer and Culvert Outlets is identified on the standard drawings in the 800 series. There are no standard drawings available for rock protection and granular sheeting. However, a typical application of rock protection is illustrated in the Structural Manual, drawing number SS16-20. 511.7 DESIGN - Not Used. 511.8 COMPUTATION These are Plan Quantity Payment items. 511.8.1 Source of Information Construction recommendations for the above tender items are found in the Geotechnical Report and Foundation Investigation and Design Report as administered by the Regional Geotechnical Section and the Foundations Office respectively. The need for the application of geotextiles with any of the associated tender items should be reviewed by the geotechnical and foundation staff on the project and should not be included automatically. 511.8.2 Method of Calculation Rip-Rap The unit of measurement for rip-rap is square metre. The areas recommended for rip-rap are scaled from the plans. Slope measurements are to be scaled from crosssections. The computation of the area is based on the width x length. Rock Protection The unit of measurement for rock protection is cubic metre. The computation of the volume for rock protection is based on the area (average width x length) x the recommended depth. Areas and slope measurements are scaled from cross sections. December 2018 Page 4 of 6 CDED B511
Granular Sheeting The unit of measurement for granular sheeting is square metre. The depth of granular to be applied, the depth of excavation required, and the possible use of geotextile are determined by the Regional Geotechnical Section and the Foundations Office. Granular sheeting does not require compaction. Slope measurements are scaled from cross-sections. Geotextile The unit of measurement for geotextile is square metre. Slope measurements are to be scaled from cross-sections. The computation of the area is based on the width x length. No allowance is made for material overlap. 511.9 DOCUMENTATION 511.9.1 Contract Drawings Areas for the above tender items are shown on the construction plan sheets. Typical sections are to be included on the drawings to clarify complex applications, geotextile anchorage, and other requirements. The depth of granular sheeting and rock protection shall be identified on a typical section. 511.9.2 Quantity Sheets Quantities are listed on the Quantities - Miscellaneous 1 sheet. Locations are documented by station to station limits and offsets left or right of the roadway centreline. The column entries are automatically totaled and transferred to the Tender Item List. 511.9.2.1 Variation Items a) Rip-Rap Rip-Rap is a variation item. The variation is the type of rip-rap (R-10 or R-50). The quantities for each type of variation are documented in separate columns on the Quantity Sheets. The variation information is entered upon creation of the individual columns and is displayed in the resultant column headings. To determine the type of rip-rap see OPSS 1004. December 2018 Page 5 of 6 CDED B511
b) Geotextile Geotextile is a variation item. The variation is the class (Class I or Class II), type (Woven or Non-woven), and filtration opening size (FOS 50-100 micron, FOS 75-150 micron, FOS 105-210 micron, or FOS 150-300 micron). The quantities for each type of variation are documented in separate columns on the Quantity Sheets. The variation information is entered upon creation of the individual columns and is displayed in the resultant column headings. The number of geotextile variations shall be minimized to the extent possible. 511.9.2.1 Documentation Accuracy Stations and quantity entries are recorded to the nearest whole number metre. Offsets are recorded in 0.1 of a metre. December 2018 Page 6 of 6 CDED B511