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  • Writer's pictureSaqib Khan

Verification of Seismic Bridge Bearings for the New Pattullo Bridge

Updated: Feb 21

At Spannovation, we offer Third-Party Checks, including Engineer of Record Services on behalf of suppliers of permanent and temporary components and equipment for bridge construction. Our expertise extends to articulation devices like bearings and joints. We specialize in the thorough verification of bearing designs, including seismic isolation bearings such as Lead Rubber and Spherical Bearings.

To ensure these devices comply with performance and durability requirements, we conduct independent calculations to verify the design against design standards. We perform out all relevant code checks according to the provisions of CHBDC CAN/CSA S6-14, our primary design standard, and AASHTO LRFD, used as a secondary supplementary standard. We also meticulously review supplier drawings for accuracy, compliance, completeness, and conformance with design calculations. Our process involves close collaboration with the supplier to finalize the design criteria, ensuring the product's practicality while adhering to project standards. This includes facilitating technical dialogue with the owner and their engineer when necessary.

Our recent project for Mageba is a testament to our approach. We provided Engineer of Record (EOR) Services for the bearings on the New Pattullo Bridge in BC. This bridge, located in a high seismic zone, consists of distinct segments, each requiring a sophisticated articulation scheme with state-of-the-art bearing devices.

Rendering of a mageba lead rubber bearing
Rendering of a mageba lead rubber bearing

The mainline of the bridge uses 73 Lead Rubber Bearings, 6 Elastomeric Bearings, and 4 Spherical Bearings. Each bearing type has different fixity conditions, including multidirectional, guided, and fixed, and load ranges from 7MN to 31MN, reflecting the diverse requirements of this complex infrastructure project. In contrast, the Hwy 17 Off Ramp uses 21 Lead Rubber Bearings with guided and fixed fixity conditions and a load range from 2MN to 7MN.

Throughout the verification process, we worked closely with Mageba to implement necessary design modifications. We also designed scaled versions of bearings for prototypes tested in labs. These tests took place at the Mageba India Testing facility and Sismalab Italy, using loading protocols we developed for Quality Control Testing, Room Temperature Testing, and Low Temperature Testing. We strictly adhered to the requirements of CAN CSA S6-14, SSID 4th Edition 2014, and Special Provision 1021 - Bearings.

Lead rubber bearing in shear deformation under lateral cyclic loading
Mageba LRB being tested in Sismalab, Italy


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