Evaluation of Segmental Bridges, Part 2 of 2

Monday, November 4, 2024  4:00 PM - 6:00 PM, Grand BR Salon D

This session examines the assessment and repair of segmental bridges and their components. Due to their design and unique components, assessments of segmental bridges require evaluations that are not typically performed in other bridges. This includes locating voids of grouted tendons, examination of post-tensioned tendon corrosion, and verification of as-built conditions. This session will include case studies that bring to light recent advances in the assessment and repair methods of segmental bridges.

Learning Objectives:
(1) Understand the mechanisms leading to the corrosion of prestressing tendons in segmental bridges;
(2) Discuss evaluation methods and techniques commonly used to locate voids and corrosion in prestressing tendons of segmental bridges;
(3) Discuss repair methods for addressing structural damage and strength deficiencies in segmental bridges;
(4) Review repair techniques to mitigate corrosion of voided prestressing tendons in segmental bridges.

Repair and Re-opening of the West Seattle Bridge

Presented By: Timothy Barry
Affiliation:
Description: Repair and Re-opening of the West Seattle Bridge Timothy Barry, PE – RS&H Abstract In March of 2020, the West Seattle Bridge was abruptly closed to traffic due to significant durability concerns for the viability of the structure. Closing this critical connection carrying over 120,000 daily users had an enormous impact on the entire City of Seattle. After completing emergency repairs to stabilize the structure, Seattle Department of Transportation began the monumental effort to develop and execute a plan to repair the structure and re-open it to the travelling public. This presentation will focus on the GC/CM contract to repair and re-open the structure as quickly and safely as possible. There are inherent challenges involved with the complex scope of repairing and reinforcing a 50-year-old structure. This endeavor was further complicated by numerous challenges such as COVID, a significant labor strike, unforeseen construction issues, a strict schedule, and intense political and public pressure, all with the citizens of Seattle eagerly awaiting its completion. Despite the obstacles, the bridge was reopened to traffic in September 2022 ending a two-and-a-half-year closure. This project is a testament to how unprecedented challenges can be overcome through innovations, creativity, and collaboration of a project team with the mutual goal of successfully delivering a project to improve the community’s lives.

Resilience of Segmental Bridges: Case Studies

Presented By: Brian Merrill
Affiliation: WJE
Description: Bridges play a critical role in our transportation infrastructure, and their resilience is paramount. This presentation will discuss case studies that demonstrate the durability and resilience of segmental bridges. The case studies will highlight assessment and evaluation techniques for segmental post-tensioned bridges as well as examples when these bridges withstood extreme forces and unexpected incidents while maintaining their functionality and safety.

Impact Echo Scanning for Grout/Void Detection in Internal and External PT Ducts

Presented By: Larry Olson
Affiliation: Olson Engineering, Inc.
Description: Segmental bridge case histories are presented for impact echo scanning to check for grouted versus void conditions in internal post-tensioned ducts. The use of supporting spectral analyses of surface waves and ground penetrating radar results for concrete cracking damage associated with PT ducts is also discussed. Research results for NDE of internal duct grout/void from the NCHRP 14-28 study CONDITION ASSESSMENT OF BRIDGE POST-TENSIONING AND STAY CABLE SYSTEMS USING NDE METHODS by Texas A&M Transportation Institute further demonstrated the successful use of impact echo scanning to detect grouted vs. void conditions in external HDPE ducts.

PT Tendon Investigation and Corrosion Mitigation

Presented By: David Whitmore
Affiliation: Vector Corrosion Technologies Ltd.
Description: Grouted post-tension tendons are susceptible to corrosion and possible reduced service life if grouting defects are present. Non-destructive evaluation techniques can be used to identify grouting defects and the presence of moisture. Repair techniques are available to address the effects of grouting defects and water infiltration. Project case studies will be used to illustrate the use of these techniques on segmental post-tensioned bridges.