Baseline Model Updating
using Truck Load Data and Strain
Figure 1. Completed Vernon Ave.
|Figure 2. On-Site Data
The Vernon Avenue Bridge over the Ware River in Barre, Massachusetts (Figures 1 and
2) is used for bridge Structural Health Monitoring (SHM). It is a continuous
three span steel stringer bridge with composite reinforced concrete deck. The
NSF Partnerships for Innovations (PFI) program has funded this project for three
years. Dr. Sarah Nerlove is the program director for this project at NSF.
Instrumentation began in June 2009 by our students and was completed in October
of 2009. Many different types of sensors were installed, including 100 strain
gauges, 16 tiltmeters, 16 accelerometers, 30 concrete deck temperature sensors,
36 girder temperature sensors, 3 ambient temperature sensors and 2 pressure
plates. A monitoring system was installed by Geocomp Corporation in order to
capture structural behavior during construction and into the service life of the
bridge (Figures 3 & 4). Strain data from the steel girders was collected during
the concrete deck pour.
We have performed two rounds of bridge load tests on 9/3/2009 and 7/30/2010. The
first test included both stop location and crawl speed load tests. The second
test included both truck crawl-speed load testing and dynamic vibration
excitation and acceleration measurements. We are also continuously monitoring
the bridge for temperature effects and its impact on load rating and long term
Figure 3. Vernon Avenue Instrumentation Plan
Figure 4. Vernon Avenue Section View
(Courtesy of FST Inc.)
Figure 5. FEM of the Vernon Ave.
Two finite element models were created using
shell/solid elements and frame/shell
elements. Both computer model responses were
compared with field strain measurements of
the full scale bridge. Both the shell/solid
and frame/shell FEMs produced close
estimates of the measured strain data. The
shell/solid model is shown in Figure 5 and a
comparison of predicted and measured strains
is shown in Figure 6. The predicted strains
closely matched with the measured strains.
The structural model that reflects the
actual bridge 3D system behavior can be used
for load rating and overload permitting.
Figure 6. Modeled and Measured Strains -
Crawl Speed Load Test
The Research Team
Professor Masoud Sanayei of Tufts University served as Principal
Investigator (PI), Associate Professor Erin Santini Bell of the
University of New Hampshire served as the Co-PI, Professor of the
Practice Brian Brenner as the Tufts University Co-PI and representative
of FST as the main industrial partner, Dr. Allen Marr of Geocomp
Corporation as the main partner for instrumentation and data acquisition.
Students at Tufts University and the University of New Hampshire
played a major role in instrumentation, data acquisition, and load
rating of the Powder Mill Bridge over Vernon Avenue using the measured
nondestructive test data. Several graduate students contributed to the
success of this project including Jesse Sipple, John Phelps, Merve Iplikcioglu,
Paul Rosenstrauch, and Peeyush Rohela of Tufts University and Paul Lefebvre,
John Welch, Eric Picard and Jason Peddle of the University of New Hampshire.
The project was supported by a grant from the National Science
Foundation, Partnership for Innovations Program. The Town of Barre,
Owner of the bridge, provided access and ongoing help with coordination
for all phases of the project. The Massachusetts Department of Transportation
likewise provided coordination and assistance. Bridge constructor E.T.&L.
Corporation, and the steel fabricator, High Steel, Inc, provided access,
assistance and coordination during bridge construction.