Bridges And Structures

Seismic Retrofit of Hollow Piles

The overall goal of the proposed research is to design, and prove experimentally, methods to seismically retrofit prestressed concrete hollow pile-columns used in bridges.  WSDOT maintains approximately 25 bridges that are supported on hollow precast, prestressed concrete pile-columns. Most were constructed in the 1960s. The seismic performance of these bridges is in now question because the hollow sections have been shown to have little flexural ductility, which may cause them to fail prematurely. This project will determine the flexural strength and deformation capacity of a typical as-built, hollow, precast, pre-tensioned pile-column before retrofitting. Researchers will then develop a retrofit method, including design procedures, for the potential plastic hinge at the cap beam connection, and they will develop implementation procedures for the retrofit method. In addition, this project will create a simple numerical modeling tool that will allow WSDOT to rank existing bridges according to the risk that they pose to help it prioritize bridge retrofitting.

Principal Investigators:
John Stanton, Civil and Environmental Engineering, UW
Paolo Calvi, Civil and Environmental Engineering, UW

Sponsor: WSDOT
WSDOT Technical Monitor: Bijan Khaleghi
WSDOT Project Manager: Doug Brodin
Scheduled completion: December 2019

Update for Steel Bridges

The last official release of a steel version of the bridge rating software that WSDOT uses was Bridg97. That software offers WSDOT’s and FHWA’s standard rating systems, both based on Load Factor Rating (LFR). Unfortunately, it depends on software packages that have become obsolete. WSDOT has also adapted a concrete version of Bridg (last official release was Bridg10), whose updated interface is platform independent.  Steel Bridg shares large portions of the user interface with concrete Bridg, and so parallel development has been dedicated to porting the steel­specific user interface into a new, platform-independent steel Bridg version, although it still has technical limitations related to WSDOT and FHWA standard rating, as well as graphics capabilities. This project is working to further upgrade the new steel Bridg by porting the load module and LRFR-specific extensions from the concrete Bridg to the improved steel Bridg software and otherwise utilizing the existing features of Bridg97.

Principal Investigator: Peter Mackenzie-Helnwein, Civil and Environmental Engineering, UW
Sponsor: WSDOT
WSDOT Technical Monitor: Mohamad Al-Salman
WSDOT Project Manager: Jon Peterson
Scheduled completion: September 2019