Probabilistic analysis of civil structures is primarily concerned with the quantification of uncertainty that results from random variations in demand and capacity throughout the service life of structures. In the case of bridges, one important source of uncertainty comes from demands induced by vehicles, i.e. vehicular live loads. Current bridge design guidelines (AASHTO LRFD) are operationally deterministic and define the vehicular live load model (HL-93) that is intended to provide a level of demand consistent with a predetermined level of reliability (reliability index of 3.5 or larger in 75 years) for most bridges.
[Truncated abstract] Many load rating methods have been developed in recent years to evaluate the safety and serviceability of existing bridges. In general, the rating of a bridge is carried out by comparing the factored live load effects of nominated rating vehicles with the available bridge capacity. Therefore, accurate and practical approaches to calculate the live load on bridges resulting from moving vehicles and to estimate the bridge load carrying capacity are essential for bridge load rating. The research described in this thesis aims to develop a load rating procedure for accurately estimating the load carrying capacity of existing bridges. It involves three main parts of work. First, to obtain a reliable Finite Element (FE) model of the bridge under the current condition, FE model updating analysis is carried out to refine the bridge model based on the field measured vibration data. Second, detailed static nonlinear Finite Element Analysis (FEA) based on the updated FE model is carried out to determine the bridge load carrying capacity. In this part, the dynamic vehicle-bridge interaction is only approximately modelled by using the code specified Dynamic Amplification Factor (DAF) or Dynamic Load Coefficient (DLC). In the third part, to more precisely model dynamic vehicle-bridge interaction and predict the DAF, nonlinear stochastic dynamic response analysis of an equivalent hysteretic Single Degree of Freedom (SDOF) system subjected to a non-stationary non-zero mean excitation are carried out. The equivalent SDOF system is derived from the actual bridge conditions. The advantages of these approaches are that they can model the actual current condition of a bridge by applying the model updating method and take into account the effects of road surface roughness, single or multiple vehicles-bridge interaction and material nonlinearity of prestressed or reinforced concrete. ... At last, based on the principle of equivalent dissipated energy, the resulting load-displacement relationship may be simplified as a bilinear hysteretic model which defines the stiffness of the equivalent SDOF system. The excitation force of the equivalent SDOF system is a non-stationary stochastic process with non-zero mean, which is caused by the vehicle weight and vehicle-bridge interaction. This thesis presents a novel approach to the evolutionary spectral analysis for the random response of a coupled vehicle-bridge system. The proposed method is capable of taking into account the random characteristics of vehicle-bridge interaction induced by road surface roughness and effect of multiple vehicles-bridge interaction. In addition, this method allows each vehicle to be modelled using a mass-spring-damper system with 4 Degrees Of Freedom (DOF). The resulting stochastic dynamic interaction force can be transformed to an excitation force of the equivalent SDOF system by applying the principle of virtual work. Once the mass, damping, stiffness and excitation force of the equivalent SDOF system are determined, the equation of motion of this SDOF system can be solved using the equivalent linearization method. The entire proposed rating procedure is applied to rating of a practical bridge located in the Shire of Roebourne in Western Australia. Also, parametric studies are conducted in this research to investigate the effects of the length ratio, vehicle to bridge frequency ratio, bridge damping ratio, vehicle to bridge mass ratio, vehicle speed, vehicle number and road surface condition on the DAF and DLC.
Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges contains lectures and papers presented at the Ninth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2018), held in Melbourne, Australia, 9-13 July 2018. This volume consists of a book of extended abstracts and a USB card containing the full papers of 393 contributions presented at IABMAS 2018, including the T.Y. Lin Lecture, 10 Keynote Lectures, and 382 technical papers from 40 countries. The contributions presented at IABMAS 2018 deal with the state of the art as well as emerging concepts and innovative applications related to the main aspects of bridge maintenance, safety, risk, management and life-cycle performance. Major topics include: new design methods, bridge codes, heavy vehicle and load models, bridge management systems, prediction of future traffic models, service life prediction, residual service life, sustainability and life-cycle assessments, maintenance strategies, bridge diagnostics, health monitoring, non-destructive testing, field testing, safety and serviceability, assessment and evaluation, damage identification, deterioration modelling, repair and retrofitting strategies, bridge reliability, fatigue and corrosion, extreme loads, advanced experimental simulations, and advanced computer simulations, among others. This volume provides both an up-to-date overview of the field of bridge engineering and significant contributions to the process of more rational decision-making on bridge maintenance, safety, risk, management and life-cycle performance of bridges for the purpose of enhancing the welfare of society. The Editors hope that these Proceedings will serve as a valuable reference to all concerned with bridge structure and infrastructure systems, including students, researchers and engineers from all areas of bridge engineering.
The topic of Uncertainty Quantification (UQ) has witnessed massive developments in response to the promise of achieving risk mitigation through scientific prediction. It has led to the integration of ideas from mathematics, statistics and engineering being used to lend credence to predictive assessments of risk but also to design actions (by engineers, scientists and investors) that are consistent with risk aversion. The objective of this Handbook is to facilitate the dissemination of the forefront of UQ ideas to their audiences. We recognize that these audiences are varied, with interests ranging from theory to application, and from research to development and even execution.
Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges contains lectures and papers presented at the Ninth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2018), held in Melbourne, Australia, 9-13 July 2018. This volume consists of a book of extended abstracts and a USB card containing the full papers of 393 contributions presented at IABMAS 2018, including the T.Y. Lin Lecture, 10 Keynote Lectures, and 382 technical papers from 40 countries. The contributions presented at IABMAS 2018 deal with the state of the art as well as emerging concepts and innovative applications related to the main aspects of bridge maintenance, safety, risk, management and life-cycle performance. Major topics include: new design methods, bridge codes, heavy vehicle and load models, bridge management systems, prediction of future traffic models, service life prediction, residual service life, sustainability and life-cycle assessments, maintenance strategies, bridge diagnostics, health monitoring, non-destructive testing, field testing, safety and serviceability, assessment and evaluation, damage identification, deterioration modelling, repair and retrofitting strategies, bridge reliability, fatigue and corrosion, extreme loads, advanced experimental simulations, and advanced computer simulations, among others. This volume provides both an up-to-date overview of the field of bridge engineering and significant contributions to the process of more rational decision-making on bridge maintenance, safety, risk, management and life-cycle performance of bridges for the purpose of enhancing the welfare of society. The Editors hope that these Proceedings will serve as a valuable reference to all concerned with bridge structure and infrastructure systems, including students, researchers and engineers from all areas of bridge engineering.
This book is organized around the various sensing techniques used to achieve structural health monitoring. Its main focus is on sensors, signal and data reduction methods and inverse techniques, which enable the identification of the physical parameters, affected by the presence of the damage, on which a diagnostic is established. Structural Health Monitoring is not oriented by the type of applications or linked to special classes of problems, but rather presents broader families of techniques: vibration and modal analysis; optical fibre sensing; acousto-ultrasonics, using piezoelectric transducers; and electric and electromagnetic techniques. Each chapter has been written by specialists in the subject area who possess a broad range of practical experience. The book will be accessible to students and those new to the field, but the exhaustive overview of present research and development, as well as the numerous references provided, also make it required reading for experienced researchers and engineers.
This proceedings volume contains papers presented at the Third Scientific Meeting of the IFIP Working Group on "Reliabilty and Optimization of Structural Systems". The contributions reflect recent developments in the field of modern structural systems optimization and reliability theory and point out directions for further research. Also perspectives for the education in this field were discussed.
