The objective of this work is to develop an interactive physical-computer model for the structural health monitoring of highway bridges during extreme natural events such as earthquakes and flooding. The physical model, representing a highway bridge in Iowa, will provide the adequate measurements, a computer finite element model will update and predict the changes in the loading capacity of the bridge during and after the event, and a damage detection and health monitoring scheme will assess the integrity of the bridge.

1. Infrastructure Inspection during and after
Unexpected Events
Department of Civil & Environmental Engineering,
College of Engineering,
The University of Iowa
Corey Markfort
Assistant Professor (Co-PI)
Ali Karimpour
(Graduate Student)
Salam Rahmatalla
Professor (PI)

2. Challenges from natural events
During and after extreme natural events, bridges’ loading capacity become unpredictable!
https://www.youtube.com/watch?v=ReJdwTHrF3k

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 Before the event: Emergency responders do not have information about the health
condition of bridges and their loading capacity to make plans for readiness and
logistics.
 During the event: Emergency responders do not have enough information about
the damage status and loading capacity of bridges to make plans for management,
logistics, and safety.
 After the event: Emergency responders do not have information about damage
levels on bridges to make plans for maintenance, repair, and logistics.
Challenges to emergency responders

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The goal of this work is to develop a computer model to:
Predict bridges’ loading capacity before the flood, based on information
from Iowa Flood Center (IFC).
 Update IFC map from graphic based
to physics based (long-term goal)
 Predict bridge loading capacity and health monitoring during and after
the flood based on finite element modeling and field measurements.

5. UI contribution
This is a multidisciplinary problem that requires background and facilities in
structural health monitoring, structure/fluid interaction, and weather/flooding
prediction.
Capability
UI has the expertise, facilities (IFC, IIHR, and CCAD), and infrastructure to tackle
the problem.
Goal--to develop safety metrics for bridges to:
 Provide bridges’ owners with information about bridges’ health condition for
decision making, logistics, planning, and maintenance.
 Provide mitigation and safety solutions.

6. Earthquake and vibration simulation system.
State-of-the-art motion sensing systems.
State-of-the-art modeling and simulation
capabilities.
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PLAY
ME
Facilities: Center for Computer-Aided Design (CCAD)

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Sample of FSI Researches in Water Flume9/30/2019
UI Hydrolic Lab (Wind & WaterWavesimulator)
Wind Tunnel Laboratory
Flood and water wave simulation
(Water Flume)
Flood and water wave generation
via wind.
Facilities: IIHR - Hydroscience and Engineering

8. ~33,600 cfs
2008
145,000 cfs
Flood
No flood
31 floods
in 106 years
1993
2016
Facilities: Iowa Flood Center
Annual Flood Time Series

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Configuration of the modeling process from prototype to small-scale model: (a) view of single-span bridge
(FHWA#31690); (b) schematic of the grid system of its composite beam; (c) the CAD model; (d) the physical small-
scale model.
Development of physical and FE computer models

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Configuration of the FE model: Point “B” is the input as well as the 1st output location,
Point “A” is the 2nd output location.
Numerical testing of FE model

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The model showed good behavior during impact and shaker testing but was too stiff to show any
observable behavior during the flume testing.
Numerical testing of FE model

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(a) The shaker setup testing, (b) the data acquisition system (DAS) and its associated trigger, (c) the
waterproofed sealed accelerometer and gyroscope attached to the girder
Experimental testing of physical model

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Simulating the mass alterations in the system (Damage Scenario I): (a) Intact model: without
added mass; (b) Damage level 1 (D1): one piece of artificial mass was loaded; (c) Damage
level 2 (D2): two pieces of artificial masses were loaded.
Damage simulation and testing of physical model

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Damage index extracted from different sensors and effective DI using Damage Scenario I with damage intensity D1 and D2
Damage detection of physical model

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Experimental testing of physical model inside a water flume

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Modeling process configuration from prototype to small-scale bridge: (a) site view of the prototype (FHWA #33472);
(b) construction blueprints of the prototype provided by Iowa DOT; (c) the model, which is a two-span, small-scale prototype
with five mid-piers inside the water flume; (d) the model equipped with six-degree-of-freedom inertial motion sensors.
Development of physical model of a multi-span bridge

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Testbed setup at the water flume with sensors installed on the spans; the coordinate system shows the force and motion
nomenclature and definitions.
Experimental testing of physical model inside the water flume

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Testing the model under different stages at the University of Iowa flume lab: (a) the first stage represents pure noise;
(b) the second stage represents flood initiation; (c) the third stage represents a harsh flood; and (d) the fourth stage
represents an extreme flood event in which the model was inundated.
Experimental testing of physical model inside the water flume

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Mid-span footing system and corresponding column numbers used for the three damage scenarios.
Experimental testing of physical model inside the
water flume under different damage scenarios

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Damage index at different flood stages and different damage scenarios
Damage detection of physical model

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Development of a computer model of a multi-span bridge
Prototype Bridge Physical Model
Computer Model

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Flood loading: numerical simulation (CFD )
CFD estimates and imposes forces from flood on the superstructures of the highway bridge
during the extreme event.
Forces can be fed to the computer model, then the computer model checks whether the
structure can withstand the imposed loading or not.

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 Various truck loadings and moving loads will be simulated and applied to the computer
model.
 Flood loading will be estimated and fed to the computer model.
 The computer model will give a red flag when the loading is not safe.
Bridge loading capacity with traffic

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Expected products: a computer model that can:
 Predict bridges’ loading capacity before the event based on information from IFC
(Product 1).
 Predict bridges’ loading capacity and health monitoring during and after the
event based on FE modeling and measurements (Product 2).
 Update IFC map from graphic based to physics based (Product 3/Long-term
product).

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Thank You!