2474High-Load Multi-rotational Bearings

2474.1DESCRIPTION

Provide high-load multi-rotational (HLMR) bearing assemblies for use in Bridges and other Structures. A Definitions For the purpose of the Work specified in section 2474, “High-Load Multi-Rotational Bearings,” the Department defines:

Fixed Bearings Allow rotation in the vertical plane, but no longitudinal or transverse movement in the horizontal plane. Guided Bearings Allow rotation in the vertical plane and movement in a horizontal plane in the longitudinal or transverse direction of the Bridge, as defined in the Plan. Horizontal movement in a direction transverse or longitudinal to the Bridge shall be restricted, as defined in the Plan. Non-guided Bearings Allow rotation in the vertical plane and horizontal movements in all directions .

2474.2MATERIALS

Ensure all Materials used in the manufacture of pot and disc bearings are new and unused, with no reclaimed Material incorporated into the finished product.

2474.3CONSTRUCTION REQUIREMENTS

A General Perform the Work in accordance with the applicable requirements of 1703, “Patented Devices, Materials, and Processes,” 2402, “Steel Bridge Construction,” 2471, “Structural Metals,” the Plans, and the following: Before the start of Work, the supplier will be qualified on Approved Suppliers for Fabricated Structural Metals Products list as maintained by the Structural Metals Engineer on the Bridge office website or become qualified. To become qualified, the supplier is to submit a Quality Manual (QM) to the Bridge Engineer for review and acceptance, at least 60 Calendar Days before beginning Work. The QM is to meet the requirements of the MnDOT Supplier Qualification Standard which will be the basis for acceptance by the Bridge Engineer. Upon acceptance of the QM, a supplier is qualified and will be listed on the Approved Suppliers for Fabricated Structural Metals Products list . In addition to routine inspections, the Bridge Engineer will audit suppliers with approved QMs on a biannual or annual basis or as otherwise directed by the Bridge Engineer to ensure the implementation of the QM. The Department will invoke its Corrective Action Process if the routine inspections or audits indicate non-conformance. Corrective actions deemed appropriate by the Bridge Engineer, are effective immediately and apply to any Work remaining on a current and future Projects. If the Bridge Engineer determines that Work does not comply with the QM or that fabrication does not follow approved fabrication procedures, the Bridge Engineer will deem the Materials as non-conforming in accordance with 1503, “Conformity with Contract Documents,” and 1512, “Unacceptable and Unauthorized Work.” If the Bridge Engineer finds non-conforming Work, direct the supplier to immediately correct the procedure and submit a written Nonconformance Report, containing data required by the Bridge Engineer to ensure compliance with the QM, Specifications, and drawings. Perform additional testing as required by the Bridge Engineer at no additional cost to the Department. For repeat offences or negligence, the Department will require corrective action of hiring a third-party Quality Control Inspector at no additional cost to the Department. The Contractor may obtain a copy of the Department’s Corrective Action Process from the Bridge Engineer. A.1 Bearing Types Three types of bearings are specified in the Plans; Fixed, Guided, and Non-guided bearings, of varying load capacities. A.2 Shop Drawings Shop drawings for the bearing assemblies shall include, but not be limited to, the following:

bearing assemblies

responsible for coordination of production, inspection, sampling, and testing

described and detailed

as the mean temperature for zero-inch offset Supplemental to the shop drawings, furnish design calculations which indicate that the bearings furnished by the manufacturer are adequate for the requirements of the Contract. Calculations shall include rotation and horizontal movement capacity, and compression stresses on elastomeric and sliding surfaces. Furnish an erection Plan to the Engineer at or before the time of delivery showing the location and orientation of each of the bearings. A.3 Bearing Dimension Options Overall heights of the bearing assemblies, including the sole plates, are given in the Plans. The bearing manufacturer shall determine the thickness of the masonry and sole plates through design of the bearing assemblies and set the final height, Dimension “ H,” of each of the assemblies. Horizontal dimensions given for the masonry plates may be changed by the manufacturer in accordance with design. Anchor rod offsets from the centerline Pier/centerline Bearing shall remain as shown in the Plans to avoid causing interference of the anchor rods with the main reinforcement in the bearing seats. If the final height of the bearing assemblies is different from that given in the P lans, the manufacturer shall clearly indicate the revised Dimension “H” and provide new bearing seat elevations to the Engineer. A.4 Design and Fabrication Requirements Design the bearings so that the pot cylinder and piston assembly of pot bearings, and the disc and both mating surfaces of disc bearings, can be removed for replacement or repair. Provide for vertical and lateral loads, movements from temperature changes, rotation, camber changes, and the effects of creep/shrinkage of post-tensioned concrete box girders. Service and strength limit state design loads and movement values are given in the P lans. Ensure Materials used in the manufacture of disc and pot bearings are new and unused, with no reclaimed material incorporated into the finished product. Size stainless steel sliding surfaces to completely cover the PTFE surfaces in operating positions plus one additional inch in all directions of movement as given in the Plans except transversely in Guided Bearings. Do not start fabrication of the bearing assemblies until the shop drawings have been approved by the Bridge Engineer. Ship upper and lower components of the bearings to the job site fully assembled.

B Disc Bearings Ensure disc bearings consist of an elastomeric structural rotational element (disc) confined by upper and lower steel bearing plates plus masonry and sole plates. The function of the bearings is to transfer loads and accommodate relative movement, including rotation, between the B ridge Superstructure and the piers. Ensure disc bearings are produced by a firm specializing in the design and manufacture of disc bearings, with a minimum of 8 years of successful bearing installations. Design, fabricate, and test in accordance with the requirements of the AASHTO LRFD Bridge Design Specifications, Article 14.7.8, Disc Bearings and the AASHTO LRFD Bridge Construction Specifications, Article 18.3, Pot and Disc Bearings. Provide the Bridge Engineer with written notification of bearing testing at least 30 Calendar Days prior to the start of testing operations. Ensure fabrication of the disc bearings conforms to the applicable requirements of AASHTO LRFD Bridge Construction Specifications, Article 18.3.3. C Pot Bearings Ensure pot bearings consist of a confined elastomeric element encased in steel, the function of which is to transfer loads and accommodate relative movement, including rotation, between the B ridge Superstructure and the piers and abutments. All Material shown in the Plans for a single pot bearing unit shall make up an assembly. Ensure pot bearings are produced by a firm specializing in the design and manufacture of pot bearings, with a minimum of 8 years of successful bearing installations. Design, fabricate, and test in accordance with the requirements of AASHTO LRFD Bridge Design Specifications, Article 14.7.4 Pot Bearings and the AASHTO LRFD Bridge Construction Specifications , Article 18.3, Pot and Disc Bearings. Ensure brass sealing rings are rectangular cross-section conforming to AASHTO LRFD Bridge Design Specifications, Article 14.7.4.5.2 with no less than 3 rings per bearing assembly. Provide the Bridge Engineer with written notification of bearing testing at least 30 Calendar Days prior to the start of testing operations.

2474.4METHOD OF MEASUREMENT

The Department will measure High-load multi-rotational bearings by the number of acceptable units of each type provided, which consists of all components shown in the Plans or on the approved shop drawings for a single bearing assembly, whether it is a pot or disc bearing.

2474.5BASIS OF PAYMENT

The Contract Unit Price for High-load multi-rotational bearings includes the cost of providing and installing the pot or disc bearings complete in-place. The Department will pay for bearings on the basis of the following schedule: Item No. Item Unit

2474.502 High-load Multi-rotational Bearings each