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Guidelines for Certification and Management of Flexible Rockfall Protection Systems (2016)

Chapter: Chapter 6 - Proposed Performance-Based Special Provision for Rockfall Fence Systems

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Suggested Citation:"Chapter 6 - Proposed Performance-Based Special Provision for Rockfall Fence Systems." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for Certification and Management of Flexible Rockfall Protection Systems. Washington, DC: The National Academies Press. doi: 10.17226/23519.
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Suggested Citation:"Chapter 6 - Proposed Performance-Based Special Provision for Rockfall Fence Systems." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for Certification and Management of Flexible Rockfall Protection Systems. Washington, DC: The National Academies Press. doi: 10.17226/23519.
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Page 21
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Suggested Citation:"Chapter 6 - Proposed Performance-Based Special Provision for Rockfall Fence Systems." National Academies of Sciences, Engineering, and Medicine. 2016. Guidelines for Certification and Management of Flexible Rockfall Protection Systems. Washington, DC: The National Academies Press. doi: 10.17226/23519.
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Page 22

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20 C H A P T E R 6 The following is a proposed performance-based special provision for agencies to use when bidding and contracting rockfall fence system work. REVISION OF SECTION XXX.XX (Commentary: A performance specification is provided. This is intended to be modified for use with standard or special provi- sions per agency requirements. Various federal and state agencies have specific standard or special provisions relating to rockfall fences based on design assumptions, past experiences, and in- house procedures and protocols per specific agency requirements). ROCKFALL FENCE Section XXX of the Standard Specifications is hereby revised for this project to include the following: DESCRIPTION This work consists of construction of a rockfall fence to mitigate potential rockfall as designated on the Plans. Instal- lation shall be at the locations designated on the Plans unless otherwise directed. (Commentary: Definitions of the systems vary from region to region and state to state. Clarify what the system is, for example, Flexible Rockfall Fence, Rockfall Fence, or Rockfall Barrier). DEFINITIONS The bid item for Rockfall Fence is considered a ______ kJ, ____ high, tested rockfall fence system. (Commentary: The agency or designer typically assesses the energy requirements of the rockfall fence based on an evaluation of the site conditions and rockfall energies using appropriate methods for Design-Bid-Build (DBB) projects. Other contract- ing methods may have different requirements). CONSTRUCTION REQUIREMENTS The rockfall fence shall be installed in accordance with the submitted Shop Drawings and in the locations shown on the plans or as marked by the Engineer for the specified rockfall fence system as shown on the Plans. (Commentary: The agency or designer typically evaluates the energy requirements of the rockfall fence based on an evalua- tion of the site conditions and rockfall energies using appropri- ate methods for DBB projects. Other contracting methods may have different requirements). SUBMITTALS Shop Drawings shall be in accordance with Standard Spec- ification ________. (Commentary: Agencies typically have Shop Drawing stan- dard provisions. The requirement for a Professional Engineer seal on the Shop Drawings can be evaluated by the agency). At least ______ days prior to the beginning of construction the Contractor shall submit detailed Shop Drawings of the rockfall fence system. The diameters and dimensions of materials in the sub- mitted Shop Drawing system shall be equal strengths to the metric equivalents for the submitted ETAG 27 tested systems and requirements of this special provision (i.e., diameter of wire rope in fence panels, diameter of lacing ropes, and diameter of anchor ropes shall be sized for equal strength to the metric equivalents). The Contractor and/or Rockfall Fence Manufacturer shall outline differences (if any) between the two systems. If the differences are signifi- cant, the Engineer may require written justification for the change or require the tested elements be incorporated into the Shop Drawings. The Shop Drawings shall include the following minimum information: (a) Plan view locations for the rockfall fence system show- ing location of all elements associated with the rockfall system (b) Description of the construction sequence (c) Details for the fence panel system Proposed Performance-Based Special Provision for Rockfall Fence Systems

21 (d) Details for the fence panel mesh layer connection to the fence net panel (e) Details of the connection between the fence panel and wire support rope (f) Details for the supporting posts (g) Details of the net panel’s lateral and retaining wire ropes with brakes (h) Details of the rock and/or soil anchor systems with applicable design pullout loads (i) Details of the post support and base (j) Required torque for all bolts and fasteners (k) Grout and concrete requirements (per agencies’ requirements) (l) Documentation that the rockfall fence system has been tested in accordance with ETAG 27 (m) A completed ETAG 27 Rockfall Fence Test Data Request Form METHOD OF MEASUREMENT Rockfall fence will be measured and paid by the linear feet that are installed and accepted. BASIS OF PAYMENT The accepted quantity of work will be paid for at the con- tract price per unit of measurement for the pay items listed below. Payment for a _______ kJ system will be made under Rockfall Fence. Pay Item Pay Unit Rockfall Fence Linear Foot ETAG 27 ROCKFALL FENCE TEST DATA REQUEST FORM This form is intended to be used by federal and state transportation agencies to request rockfall fence test data for fences that have been tested and approved according to ETAG 27. Agencies may send this form to the fence manufacturer to request the documentation and data described below. The manufacturer may fill in the appropriate information and complete the checklist providing the requested information or the manufacturer may provide a separate report containing the requested information. Manufacturer Fence Model/Type Energy Level Classification/Energy Test Institution Test Location Rock/Block Delivery Method Vertical Drop Inclined Cable Date of Testing Date of Approval DOCUMENTATION AND TEST DATA CHECKLIST Provide system documentation including plans, installation manual/guide, and description of system components. Verify and document that ropes, cables, nets, posts, and other components used in the United States have equivalent strength as those tested according to ETAG 27. Nominal Height Post Dimensions (Width/Flange/Thickness) Post to Foundation Connection Type Panel Width/Post Spacing Panel Type Applied Mesh Type Retaining Rope Dimensions Anchor Type and Diameter Type and Locations of Energy Dissipating Devices First Service Energy Level (SEL) Test Data Block Energy at Impact Residual Height Maximum Elongation Braking Time Force Measurements Provide a description below of fence behavior including damage and deformations of components.

22 ETAG 27 ROCKFALL FENCE TEST DATA REQUEST FORM (CONTINUED) Second Service Energy Level (SEL) Test Data Block Energy at Impact Residual Height Maximum Elongation Braking Time Force Measurements Provide a description below of fence behavior including damage and deformations of components. Maximum Energy Level (MEL) Test Data Maintenance Performed after SEL Tests Block Energy at Impact Residual Height Category Residual Height Maximum Elongation Repair Replacement None A B C Braking Time Force Measurements Provide a description below of fence behavior including damage and deformations of components. Manufacturer Representative Signature and Date (Attach Original ETAG 27 Document)

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TRB's National Cooperative Highway Research Program (NCHRP) Report 823: Guidelines for Certification and Management of Flexible Rockfall Protection Systems provides advice on rockfall fence systems for transportation agencies. It also outlines data that are needed to evaluate the results of rockfall fence systems tested using the procedure recommended for acceptance. Finally, the report presents guidelines for asset management for rockfall fence systems to assist transportation agencies in incorporating these systems into existing transportation asset management plans.

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