ONTARIO PROVINCIAL STANDARD SPECIFICATION

Transcription

1 ONTARIO PROVINCIAL STANDARD SPECIFICATION METRIC OPSS 539 NOVEMBER 2003 CONSTRUCTION SPECIFICATION FOR TEMPORARY PROTECTION SYSTEMS TABLE OF CONTENTS SCOPE REFERENCES DEFINITIONS SUBMISSION AND DESIGN REQUIREMENTS MATERIALS EQUIPMENT - Not Used CONSTRUCTION QUALITY ASSURANCE MEASUREMENT FOR PAYMENT - Not Used BASIS OF PAYMENT APPENDICES 539-A Commentary SCOPE This specification covers the requirements for the design, construction, maintenance, monitoring, and removal of a temporary protection system used in conjunction with earth excavation, embankment construction, and dewatering Significance and Use of Appendices Appendices are not a mandatory part of this specification unless invoked by the Owner. Appendix 539-A is a commentary appendix to provide designers with information on the use of this specification in a Contract. Page 1 Rev. Date: 11/2003 OPSS 539

2 REFERENCES This specification refers to the following standards, specifications, or publications: Ontario Provincial Standard Specifications, Construction OPSS 538 OPSS 903 OPSS 904 OPSS 906 OPSS 942 Support Systems Deep Foundations Concrete Structures Structural Steel for Bridges Prestressed Soil and Rock Anchors Ontario Provincial Standard Specifications, Material OPSS 1350 OPSS 1601 Concrete - Materials and Production Wood - Material, Preservative Treatment, and Shop Fabrication Canadian Standards Association S6-00 Canadian Highway Bridge Design Code Ministry of Transportation Publication Structural Manual Division 1, Exceptions to the Canadian Highway Bridge Design Code Provincial Statute Occupational Health and Safety Act R.S.O c. O. 1, as amended Ontario Regulations 213/91 - Regulations for Construction Projects, as amended DEFINITIONS For the purpose of this specification, the following definitions apply: Anchor means: a) A system consisting of prestressed tendons or non-prestressed rods installed in predrilled holes and encapsulated in grout or concrete. A system that derives its load carrying capacity in bond between the grout/concrete body and the surrounding soil or rock; or b) A tie back to a deadman. Bracing means the system of wales, struts, rakers, anchors and like members that connect frames, shores or panels of a sheathing system to resist applied pressures and providing stability against lateral movement. Cofferdam means a water tight protection system. Dredge Line means the exposed lower limit of the shoring wall. Engineer means a professional engineer, licensed by the Professional Engineers of Ontario to practice in the Province of Ontario. Erector means a person that undertakes the construction of a protection system. Page 2 Rev. Date: 11/2003 OPSS 539

3 Protection System means the construction necessary to mechanically support existing or proposed work such that its function will not be affected or the construction necessary to support work such as open excavations during the work for safety and convenience. Raker means a structural member inclined to the front of the shoring wall providing lateral support. Shoring Wall means a structural wall consisting of wood, steel, concrete or combination of these materials that supports earth, rock or water and any structure, materials, utilities or other facility contained in or on the supported earth or rock mass SUBMISSION AND DESIGN REQUIREMENTS General Alternative protection system designs to those specified in the Contract Documents will only be considered when the Contractor demonstrates there is a definite monetary advantage to the Owner Submissions Working Drawings General Working Drawings shall be submitted to the Contract Administrator when support systems are required according to the Occupational Health and Safety Act. Five copies of the Working Drawings shall be submitted five weeks before commencement of construction of the protection system where other Authorities are involved, and three weeks before commencement of construction of the protection system in all other cases Owner Designed Protection Systems When proposals modifying the design are submitted, the Working Drawings shall be signed and sealed by the design and checking Engineers Contractor Designed Protection System The Working Drawings shall be signed and sealed by the design and checking Engineers Prestressed Anchors Prestressed anchor submissions shall be according to OPSS Information To Be Shown on the Working Drawings a) Plan, elevations, and details i. Location of protection system and station limits. ii. Plan and elevation of shoring wall showing the extent of the protection system. iii. Details of the shoring wall system including cross-sections. iv. Details of internal bracing. Page 3 Rev. Date: 11/2003 OPSS 539

4 b) Design criteria i. Pressure diagrams, including values of horizontal and vertical loads, dead load, and live load surcharge. ii. Design assumptions and parameters. iii. Anchor bond stresses. iv. Pile and anchor system load table specifying working loads, stressing loads, and lock in loads. v. Details of preload where required. c) Materials i. Grade and sizes of structural steel and structural wood. ii. Concrete strength. iii. Grout strength. iv. Details of patented accessories, including load test data. v. Details of protection from rain and frost action. vi. Wood lagging and size. vii. Type of piles. d) Installation procedure i. Installation sequence and procedure, including but not limited to the installation of piling, bracing, lagging, rakers, and anchor systems. e) Monitoring Method i. Proposed method of monitoring performance of the shoring wall during installation, and shoring wall use, including the monitoring points, when the method of monitoring is not specified in the Contract Documents. The method of monitoring shall be according to the requirements of the subsection for Quality Control. f) Removal of Protection System i. Detailed procedure of removal indicating method, sequence of work, and removal limits, except when the protection system is specified in the Contract Documents to be left in place Return of Submissions Two copies of each submission to be returned shall be marked as one of the following: a) Stamped with the wording that allows for permission to construct. In this case, work can commence on receipt of the drawing by the Contractor. A copy of these drawings shall be available at the site prior to and during construction. b) Stamped with the wording that allows for permission to construct as noted. In this case, work can start on receipt of the drawings by the Contractor. The drawings shall be updated as noted and shall have a stamp affixed that is signed by an Engineer stating the drawings have been revised according to the noted comments. A copy of the stamped updated drawings shall be available at the site prior to and during construction. c) Showing only required changes. In this case, the drawings shall be updated as required and the submission process repeated. Page 4 Rev. Date: 11/2003 OPSS 539

5 Design General The protection system shall be designed for the performance level specified in the Contract Documents. Except for Owner designed protection systems, the Contractor shall be responsible for the complete detailed design of the protection system required to carry out the work shown in the Contract Documents. The design shall be according to CAN/CSA S6 and the Structural Manual, Division 1, and shall be appropriate for the specific site conditions. A protection system shall be designed to provide protection at the locations specified in the Contract Documents and at any other location where the stability, safety, or function of an existing facility may be affected by construction work. The recommended design parameters for the calculation of earth pressures, angle of internal friction of soil, bulk unit weight of soil, and bond stress for anchors shall be as specified in the Contract Documents. These values shall be used unless otherwise approved in writing by the Contract Administrator. When this information is not provided, the Contractor shall be responsible for their determination. The buoyant unit weight shall be calculated for the material below the water table shown in the Contract Documents Qualification of Designer The design and checking of the protection system shall be performed by Engineers having a minimum of five years experience on projects of similar nature and scope as the specified work Lateral Movement of the Shoring Wall Lateral movement of any portion of the protection system shall not exceed the following: Performance Level Level 1 Level 2 Level 3 Angular Distortion 1:1000 but shall not be more than 10 mm Angular Distortion 1:200 but shall not be more than 25 mm Angular Distortion 1:100 but shall not be more than 50 mm Angular Distortion = ± /H ± = Horizontal displacement at height H in mm H = Height above dredge line to the point of measurement or the height above the nearest support in mm. Where any part of a structure foundation is within a horizontal distance of 1/3 H from the face of the protection system, movement of the protection system shall not exceed 5 mm. When performance level 1 is specified and the shoring wall movement is restricted to 5 mm, the bracing system shall be preloaded. When the bracing systems are preloaded, the affects of the preload shall not cause damage to adjacent facilities. Page 5 Rev. Date: 11/2003 OPSS 539

6 Design Assumptions The design assumptions shall accurately represent the subsurface conditions prevalent at the site and shall be specific to the type of protection system used. Vertical and horizontal loadings used shall represent existing conditions and accepted design practice. Future loadings that are known and may affect the protection system during its useful life shall be considered MATERIALS Wood Wood shall be according to OPSS 1601; shall be of the size, grade, and species shown on the Working Drawings; and in sound condition, free from defects which will impair its strength. Wood lagging does not have to be grade stamped Proprietary Shoring and Patented Devices When proprietary shoring or patented accessories are to be used, the Contractor shall not assume a load carrying capacity greater than that recommended by the manufacturer. The recommended load carrying capacities shall be supported by test results from a qualified and recognized testing laboratory Concrete Concrete shall be according to OPSS Other Materials The designer may consider other suitable materials when sufficient information is available to quantify the allowable design loads or when the manufacturer's recommendations as to load carrying capacities are supported by test results from a laboratory approved by an organization accredited by the Standards Council of Canada Rejection of Materials Material not meeting the specified standards, material which cannot be identified as complying with the specified standards or material damaged sufficiently to preclude their safe use in the work shall be rejected CONSTRUCTION General The Contractor shall be responsible for the design, materials, installation, performance, monitoring, and when specified, the removal of the protection system except for Owner designed protection systems. When protection systems are designed by the Owner, the Contractor shall construct the protection system and follow the monitoring program specified in the Contract Documents. Protection systems shall be built according to the specifications and the stamped Working Drawings. Piling shall be according to OPSS 903 and the Working Drawings. Concrete construction shall be according to OPSS 904. Page 6 Rev. Date: 11/2003 OPSS 539

7 Structural steel shall be according to OPSS 906 and the Working Drawings. Support systems shall be according to OPSS 538. Prestressed anchors shall be according to OPSS 942. The protection system shall be protected from the detrimental effects of rain and frost action. Material used in the protection system shall remain the property of the Contractor. Loss of soil from behind the shoring wall shall be prevented during and following the installation of the lagging. When cofferdams are used, they shall be sealed sufficiently to permit concrete to be placed in the dry. Tremie concrete shall be placed according to the requirements of OPSS Qualifications of Erector All work shall be performed under the direction of personnel experienced in the method of construction for the protection systems used. Such experience shall have been obtained within the preceding five years on projects of similar nature and scope to the required work Amendments to Protection Systems All amendments to any protection system shall be submitted to the Contract Administrator on revised Working Drawings and shall bear the seal and signature of the original designer. Work shall not proceed on amendments to the protection system until the Contractor has received written permission to proceed from the original designer and the Contract Administrator Certificate of Conformance Upon completion of the protection system, a certificate of conformance shall be submitted to the Contract Administrator. This certificate shall signed and sealed by an Engineer who has at least five years experience in the construction of comparable protection systems, and shall certify that the protection system has been constructed according to the stamped Working Drawings Removal of Protection Systems Protection systems shall be removed from the right-of-way unless it is specified in the Contract Documents that the protection system may be left in place. For Contractor designed protection systems, the Contractor shall obtain approval from the Ministry of the Environment and other approving Authorities when the protection system is to be left in place. Where piles are left in place the top shall be removed to at least 1.2 m below the finished grade or ground level or at least 0.6 m below a stream bed. The method and sequence of removal shall be such that there will be no damage to new work, existing work, or facility being protected. A protection system shall not be removed until after permission to remove has been given in writing by the Contract Administrator. After removal, the disturbed area of the protection system shall be restored to its original condition. Page 7 Rev. Date: 11/2003 OPSS 539

8 Quality Control In addition to the quality control measures instituted by the Contractor, the Contractor shall complete a preconstruction condition survey and monitor the protection system installation as specified herein, or as shown in the Working Drawings Preconstruction Condition Survey Prior to commencing the work, the Contractor shall submit to the Contract Administrator, a preconstruction condition survey of property and structures that may be affected by the work. The survey shall include, but not be limited to, the locations and conditions of adjacent properties, buildings, underground structures, utility services, and structures such as walls abutting the site Monitoring Monitoring shall be conducted by an Ontario Land Surveyor or an Engineer according to the monitoring program submitted with the Working Drawings or as specified in the Contract Documents. The protection systems shall be monitored during construction. Readings shall be taken on the protection system at the top, each restraint point, the dredge line, and halfway between the restraint points at each construction stage during installation of the protection system. After installation, the above readings shall be taken weekly Submission of Records All test results, observations, and records, including the preconstruction condition survey, taken before and during construction and operation of the protection system shall be recorded by the Contractor and shall be available on the site for review by the Contract Administrator. If movement of the protection system is more rapid than expected or movement approaches the allowable limit, the Contract Administrator shall be notified and suitable measures acceptable to the Contract Administrator shall be taken to ensure stability of the protection system and to ensure movement of the shoring wall does not exceed that specified in the Contract Documents As Built Drawings As built drawings shall be prepared by the Contractor according to the following: a) For all work incorporated in the completed structure. b) For all work that remains. c) As requested by the Contract Administrator. The as built drawings shall be submitted to the Contract Administrator in a reproducible format prior to Final Acceptance of the work. The as built drawings shall be signed and sealed by an Engineer QUALITY ASSURANCE The work will be observed by the Owner during all phases of the installation for adherence to the Contractor s submissions and the Contract Documents. Test results, observations, records, and preconstruction condition survey may be reviewed. Page 8 Rev. Date: 11/2003 OPSS 539

9 BASIS OF PAYMENT Protection System - Item Payment at the Contract price for the above item shall be full compensation for all labour, Equipment, and Material to do the work. When the Contract does not contain a separate item for protection systems, the contract price for the items directly associated with the protection system shall include full compensation for all labour, Equipment, and Materials required to do the work described in this specification. Page 9 Rev. Date: 11/2003 OPSS 539

10 Appendix 539-A, Commentary for OPSS 539, November 2003 Note: This appendix does not form part of the standard specification. It is intended to provide information to the designer on the use of this specification in a Contract. Designer Action/Considerations The following shall be specified in the Contract Documents: - The performance level and location of protection system, recommended design parameters of earth pressures, angle of internal friction of soil, bulk unit weight of the soil and bond stress for anchors. ( ) - The design and monitoring system, when the protection system is specified by the Owner. ( ) - Protection systems, to be left in place. ( ) - Protection system allowable movement limit. ( ) Related Ontario Provincial Standard Drawings None. Page 10 Rev. Date: 11/2003 OPSS 539