Speaking

Due to a recent directive from the Federal Highway Administration, the Arizona DOT (ADOT) was tasked with performing more thorough inspections of its canal bridges. On past inspections, the undersides of the majority of these bridges were inaccessible due to a lack of sufficient freeboard. ADOT teamed with Burgess & Niple (B&N) to quickly, efficiently and safely perform inspections on 302 locally-owned and state-owned structures within an aggressive three-month window.  

B&N’s Will Strehler will discuss the logistical challenges the team overcame to complete the inspections, including: 

• Coordinating with 14 independent canal agencies to schedule inspections based on specific timing parameters dependent on low water or canal maintenance windows
• Accessing bridges in accordance with agency-specific safety guidelines using rope access, boats or diver techniques. 

The presentation will also discuss the critical findings report, which resulted in the partial closure of an urban bridge, and our approach to training ADOT staff to properly perform future inspections. 

Following the 2007 collapse of the Interstate 35W Bridge in Minneapolis, Minnesota, the Federal Highway Administration set a mandate that state agencies prepare or update load ratings for all primary gusset plates on steel truss bridges. The information necessary to load rate gusset plates is found on design and shop drawings. However, field measurements are necessary for bridges with incomplete or missing drawings. Incorporating technology can significantly reduce the time and cost necessary to gather information in the field and expedite analysis work in the office.

For the past decade, Burgess & Niple has performed load rating of gusset plates on several of the Kentucky Transportation Cabinet’s larger truss bridges.   The completeness and quality of the plans for the bridges varied greatly among the structures which resulted in the use of a variety of approaches.

This presentation will outline the information needed to complete load rating and demonstrate how different technology applications, including sUAS, were leveraged in several Kentucky bridge projects.

In 2013, a naval ship struck a critical steel member in the center span of the Mathews Bridge in Jacksonville, Florida. The collision caused significant damage and an immediate bridge closure. 

The Mathews Bridge is a 7,375-foot-long steel cantilever thru-truss with a roadway deck that rises 150 feet above the St. Johns River. Located on the Arlington Expressway which is a main route for the city with an average daily traffic rate of 50,000, reopening the bridge promptly while ensuring the safety of the structure was essential to the community and local economy.

To minimize loads on the bridge, FDOT decided not to use mechanical access equipment for the inspection. Within hours of the bridge strike, Burgess & Niple engineers began inspecting the bridge using industrial rope access techniques, which allowed full access to all critical areas of the structure.

The team was on-site for the duration of the project, providing a range of engineering services as part of a large team of consultants, state agency personnel and contractors working together to safely and efficiently repair the structure. The bridge was reopened to traffic just 34 days after the impact.

This presentation will detail the project from start to finish, including the timeline, action plan and repair solutions, as well as the challenges faced by the project team, which included:

• Determining how to restore bridge geometry and load paths
• Replacing and strengthening tension cord and gusset plate members
• Conducting operations on a major structure without the use of mechanical access equipment or cranes
• Installation of 100+ strain gages, miles of wiring and completing load tests

With the Federal Highway Administration’s (FHWA) increased focus on addressing critical findings (Metric #21), correcting bridge deficiencies in a timely fashion has become a top priority for local agency bridge owners. It can be challenging to develop a comprehensive plan to address these deficient structures due to the variety of bridge types, the age of the structures and coordination with stakeholders, such as elected officials and non-engineers.  

This presentation will highlight cost-effective procedures used to track and mitigate critical findings during local agency fracture critical bridge inspections to address public safety, including closure, repair or replacement of the bridge. Topics include:

• What constitutes a critical finding
• The critical finding process and timeframe, using tables to record and track findings
• How to mitigate the critical finding (post, repair or close)
• Development of repair sketches that can be easily understood by a non-engineer (scour mitigation, member strengthening and bearing seat rehabilitation) 
• Best practices for communicating to key stakeholders and coordination with FHWA