VIBRATION ANALYSIS OF A STEEL TWIN I-GIRDER PEDESTRIAN BRIDGE: STRUCTURAL IDENTIFICATION AND EVALUATION OF PEDESTRIAN EXCITATION MODELS

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Moss, J. (2015). VIBRATION ANALYSIS OF A STEEL TWIN I-GIRDER PEDESTRIAN BRIDGE: STRUCTURAL IDENTIFICATION AND EVALUATION OF PEDESTRIAN EXCITATION MODELS. Unc Charlotte Electronic Theses And Dissertations.
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Abstract

Excessive vibration of footbridges caused by pedestrian excitation is an important design consideration that has received increased attention in recent years following serviceability-related failures of several notable pedestrian bridges. Numerous models have been proposed and modified for simulating both individual pedestrian footfall excitations as well as groups of persons. However, experimental validation of pedestrian load modeling has yet to be extensively performed for this challenging human-structure interaction problem. This thesis evaluates the performance of published pedestrian load models by comparing time history simulations from a calibrated finite element model of a pedestrian bridge to experimental data obtained from full-scale testing of the structure.Operational modal analysis of a steel twin I-girder span is conducted through ambient vibration monitoring using a distributed wireless sensor network with triaxial accelerometers. The experimentally obtained estimates of the modal parameters are then used to calibrate a finite element model of the structure through structural identification, or finite element model updating, using a genetic algorithm optimization routine. Following this field calibration of the dynamic properties of the model, modal superposition time history analyses of the response of the span obtained using the finite element model with published pedestrian load models are compared to experimental measurements acquired during controlled pedestrian loading. The comparisons reveal that published pedestrian load models significantly underpredict the measured peak accelerations for this case study. Parameter identification of variables within each model through optimization of the model correlation with the measured response was performed to calibrate coefficients within each model to the case study data. The results indicate that, for this structure, a single harmonic periodic load with a force amplitude larger than recommended in standardized models produced strong correlation with the measurement data.

Details
Author

Moss, Jonathan

Title

VIBRATION ANALYSIS OF A STEEL TWIN I-GIRDER PEDESTRIAN BRIDGE: STRUCTURAL IDENTIFICATION AND EVALUATION OF PEDESTRIAN EXCITATION MODELS

Physical Description

1 online resource (142 pages) : PDF

Date

2015

Degree Granting Institution

University of North Carolina at Charlotte

Abstract

Excessive vibration of footbridges caused by pedestrian excitation is an important design consideration that has received increased attention in recent years following serviceability-related failures of several notable pedestrian bridges. Numerous models have been proposed and modified for simulating both individual pedestrian footfall excitations as well as groups of persons. However, experimental validation of pedestrian load modeling has yet to be extensively performed for this challenging human-structure interaction problem. This thesis evaluates the performance of published pedestrian load models by comparing time history simulations from a calibrated finite element model of a pedestrian bridge to experimental data obtained from full-scale testing of the structure.Operational modal analysis of a steel twin I-girder span is conducted through ambient vibration monitoring using a distributed wireless sensor network with triaxial accelerometers. The experimentally obtained estimates of the modal parameters are then used to calibrate a finite element model of the structure through structural identification, or finite element model updating, using a genetic algorithm optimization routine. Following this field calibration of the dynamic properties of the model, modal superposition time history analyses of the response of the span obtained using the finite element model with published pedestrian load models are compared to experimental measurements acquired during controlled pedestrian loading. The comparisons reveal that published pedestrian load models significantly underpredict the measured peak accelerations for this case study. Parameter identification of variables within each model through optimization of the model correlation with the measured response was performed to calibrate coefficients within each model to the case study data. The results indicate that, for this structure, a single harmonic periodic load with a force amplitude larger than recommended in standardized models produced strong correlation with the measurement data.

Genre

masters theses

Subjects--Topics

Civil engineering

Degree

M.S.

Keywords

Modal Analysis
Pedestrian Bridge
Pedestrian Excitation
Structural Identification
Vibration Analysis

Subject Area

Civil Engineering

Advisor(s)

Whelan, Matthew

Committee Members

Whelan, Matthew
Weggel, David
Fang, Hongbing

Degree Note

Thesis (M.S.)--University of North Carolina at Charlotte, 2015.

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This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). For additional information, see http://rightsstatements.org/page/InC/1.0/.

Rights Holder Information

Copyright is held by the author unless otherwise indicated.

Identifier

Moss_uncc_0694N_11012

Permalink

http://hdl.handle.net/20.500.13093/etd:822