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Full-Text Articles in Engineering
Aversion And Warning Factors For Assessing Existing Reinforced Concrete Structures, Marcie Van Weerdhuizen
Aversion And Warning Factors For Assessing Existing Reinforced Concrete Structures, Marcie Van Weerdhuizen
Electronic Thesis and Dissertation Repository
In a world of aging infrastructure, sustainability initiatives require additional investment in the assessment of existing reinforced concrete structures. Reliability-based assessment should minimize costs by reducing conservatism, while ensuring levels of safety equivalent to those for new designs. Current Canadian and US provisions assign target reliability levels for structural assessment based on criteria including occupancy type, expected failure behaviour, and the effect of element failure on the overall structural integrity. These criteria are defined using discrete and qualitative parameter values. It is shown that the true structural conditions can be better represented by verifying the applicability and completeness of these …
A Review Of Probabilistic Methods Of Assessment Of Load Effects In Bridges, Eugene J. Obrien, F Schmidt, Donya Hajializadeh, X-Y Zhou, Bernard Enright, Colin C. Caprani, Simon Wilson, Emma Sheils
A Review Of Probabilistic Methods Of Assessment Of Load Effects In Bridges, Eugene J. Obrien, F Schmidt, Donya Hajializadeh, X-Y Zhou, Bernard Enright, Colin C. Caprani, Simon Wilson, Emma Sheils
Articles
This paper reviews a range of statistical approaches to illustrate the influence of data quality and quantity on the probabilistic modelling of traffic load effects. It also aims to demonstrate the importance of long-run simulations in calculating characteristic traffic load effects. The popular methods of Peaks Over Threshold and Generalized Extreme Value are considered but also other methods including the Box-Cox approach, fitting to a Normal distribution and the Rice formula. For these five methods, curves are fitted to the tails of the daily maximum data. Bayesian Updating and Predictive Likelihood are also assessed, which require the entire data for …
Nonlinear Analysis Of Isotropic Slab Bridges Under Extreme Traffic Loading, Donya Hajializadeh, A. Salam Al-Sabah, Eugene J. Obrien, Debra F. Laefer, Bernard Enright
Nonlinear Analysis Of Isotropic Slab Bridges Under Extreme Traffic Loading, Donya Hajializadeh, A. Salam Al-Sabah, Eugene J. Obrien, Debra F. Laefer, Bernard Enright
Articles
Probabilistic analysis of traffic loading on a bridge traditionally involves an extrapolation from measured or simulated load effects to a characteristic maximum value. In recent years, Long Run Simulation, whereby thousands of years of traffic are simulated, has allowed researchers to gain new insights into the nature of the traffic scenarios that govern at the limit state. For example, mobile cranes and low-loaders, sometimes accompanied by a common articulated truck, have been shown to govern in most cases. In this paper, the extreme loading scenarios identified in the Long Run Simulation are applied to a non-linear, two-dimensional (2D) plate finite …
Spatial Time-Dependent Reliability Analysis Of Reinforced Concrete Slab Bridges Subject To Realistic Traffic Loading, Donya Hajializadeh, Mark Stewart, Bernard Enright, Eugene J. Obrien
Spatial Time-Dependent Reliability Analysis Of Reinforced Concrete Slab Bridges Subject To Realistic Traffic Loading, Donya Hajializadeh, Mark Stewart, Bernard Enright, Eugene J. Obrien
Articles
Resistance and loads are often correlated in time and space. The paper assesses the influence of these correlations on structural reliability/probability of failure for a typical two-lane RC slab bridge under realistic traffic loading. Spatial variables for structural resistance are cover and concrete compressive strength, which in turn affect the strength and chloride-induced corrosion of RC elements. Random variables include pit depth and model error. Correlation of weights between trucks in adjacent lanes and inter-vehicle gaps are also included and are calibrated against Weigh-In-Motion (WIM) data. Reliability analysis of deteriorating bridges needs to incorporate uncertainties associated with parameters governing the …
The Effect Of Truck Permitting Policy On Us Bridge Loading, Eugene J. Obrien, Bernard Enright, Cathal Leahy
The Effect Of Truck Permitting Policy On Us Bridge Loading, Eugene J. Obrien, Bernard Enright, Cathal Leahy
Conference papers
No abstract provided.
Reliability-Based Bridge Assessment Using Enhanced Monte Carlo To Simulate Extreme Traffic Loading, Bernard Enright, Donya Hajializadeh, Eugene J. Obrien
Reliability-Based Bridge Assessment Using Enhanced Monte Carlo To Simulate Extreme Traffic Loading, Bernard Enright, Donya Hajializadeh, Eugene J. Obrien
Conference papers
A framework is presented for the assessment of the safety of a bridge deck under actual traffic loading using an enhanced Monte Carlo method which attempts to reduce computational cost while preserving the advantages of more conventional, computationally intensive, simulation. To generate the bridge loading scenarios, an extensive Weigh-in-Motion (WIM) database is used to calibrate a sophisticated simulation model of two-directional traffic. Traffic and vehicle characteristics are generated from statistical distributions derived from measured traffic data. Two examples are used in this study to assess the usefulness and accuracy of the enhanced method. In the first, a simple example is …
Using Weigh-In-Motion Data To Determine Aggressiveness Of Traffic For Bridge Loading, Eugene J. Obrien, Bernard Enright
Using Weigh-In-Motion Data To Determine Aggressiveness Of Traffic For Bridge Loading, Eugene J. Obrien, Bernard Enright
Articles
This paper presents results based on the analysis of an extensive database of weigh-in-motion (WIM) data collected at five European highway sites in recent years. The data are used as the basis for a Monte Carlo simulation of bridge loading by two lane traffic, both bidirectional and same-direction. Long runs of the simulation model are used to calculate characteristic bridge load effects (bending moments and shear forces), and these characteristic values are compared with design values for bridges of different length as specified by the Eurocode for bridge traffic loading. Various indicators are tested as possible bases for a “Bridge …
Monte Carlo Simulation Of Extreme Traffic Loading On Short And Medium Span Bridges, Bernard Enright, Eugene J. Obrien
Monte Carlo Simulation Of Extreme Traffic Loading On Short And Medium Span Bridges, Bernard Enright, Eugene J. Obrien
Articles
The accurate estimation of site-specific lifetime extreme traffic load effects is an important element in the cost-effective assessment of bridges. A common approach is to use statistical distributions derived from weigh-in-motion measurements as the basis for Monte Carlo simulation of traffic loading. However, results are highly sensitive to the assumptions made, not just with regard to vehicle weights but also to axle configurations and gaps between vehicles. This paper presents a comprehensive model for Monte Carlo simulation of bridge loading for free-flowing traffic, and shows how the model matches results from measurements on five European highways. The model has been …
The Effect Of Lane Changing On Long-Span Highway Bridge Traffic Loading, Bernard Enright, Colm Carey, Colin C. Caprani
The Effect Of Lane Changing On Long-Span Highway Bridge Traffic Loading, Bernard Enright, Colm Carey, Colin C. Caprani
Conference papers
Maximum loading on long-span bridges typically occurs in congested traffic conditions. As traffic becomes congested car drivers may change lane, increasing the tendency for trucks to travel in platoons. For long-span bridges this phenomenon may increase the regularity and severity of bridge repair programs, with potential significant associated costs. This research investigates the effect of lane changing by car drivers on bridge loading. A Monte Carlo simulation model in which individual car drivers probabilistically decide, based on a lane-changing bias probability, whether or not to change lane has been developed. The sensitivity of bridge loading to this factor is investigated …
Nonlinear Response Of Structures To Characteristic Loading Scenarios, Donya Hajializadeh, Eugene J. Obrien, Bernard Enright, Emma Sheils
Nonlinear Response Of Structures To Characteristic Loading Scenarios, Donya Hajializadeh, Eugene J. Obrien, Bernard Enright, Emma Sheils
Conference papers
To assess the safety of an existing bridge, the traffic loads to which it may be subjected in its lifetime need to be accurately quantified. In this paper the 75 year characteristic maximum traffic load effects are found using a carefully calibrated traffic load simulation model. To generate the bridge loading scenarios, an extensive weigh in motion (WIM) database, from three different European countries, is used. Statistical distributions for vehicle weights, inter-vehicle gaps and other characteristics are derived from the measurements, and are used as the basis for Monte Carlo simulations of traffic representing many years. An advantage of this …
Probabilistic Study Of Lifetime Load Effect Distribution Of Bridges, Donya Hajializadeh, Eugene J. Obrien, Bernard Enright, Colin C. Caprani, Emma Sheils, Simon Wilson
Probabilistic Study Of Lifetime Load Effect Distribution Of Bridges, Donya Hajializadeh, Eugene J. Obrien, Bernard Enright, Colin C. Caprani, Emma Sheils, Simon Wilson
Conference papers
Assessment of highway bridge safety requires a prediction of the probability of occurrence of extreme load effects during the remaining life of the structure. While the assessment of the strength of an existing bridge is relatively well understood, the traffic loading it is subject to, has received less attention in the literature. The recorded traffic data are often limited to a number of days or weeks due to the cost of data collection. Studies in the literature have used many different methods to predict the lifetime maximum bridge load effect using a small amount of data, including fitting block maximum …
Estimation Of Lifetime Maximum Distributions Of Bridge Traffic Load Effects, Eugene J. Obrien, Donya Hajializadeh, Emma Sheils, Bernard Enright
Estimation Of Lifetime Maximum Distributions Of Bridge Traffic Load Effects, Eugene J. Obrien, Donya Hajializadeh, Emma Sheils, Bernard Enright
Conference papers
This paper considers the problem of assessing traffic loading on road bridges. A database of European WIM data is used to determine accurate annual maximum distributions of load effect. These in turn are used to find the probability of failure for a number of load effects. Using the probability of failure as the benchmark, traditional measures of safety – factor of safety and reliability index – are reviewed. Both are found to give inconsistent results, i.e., a given factor of safety or reliability index actually corresponds to a range of different probabilities of failure.
Lane Changing Control To Reduce Traffic Load Effect On Long-Span Bridges, Colin C. Caprani, Bernard Enright, Colm Carey
Lane Changing Control To Reduce Traffic Load Effect On Long-Span Bridges, Colin C. Caprani, Bernard Enright, Colm Carey
Conference papers
Long span bridges are critical parts of a nation’s infrastructure network and congested traffic loading is the governing form of traffic loading. Groups of trucks travelling in conveys are created when fast-er moving vehicles, such as cars, change lane. In this research the authors investigate how the control of these lane-changing events can help reduce the traffic load effects on long span bridges. Real traffic data is used to simulate a traffic stream on a virtual road and bridge using a microsimulation model. Various lane-changing restrictions are examined and compared to the typical case of free lane changing. It is …
Importance Of The Tail In Truck Weight Modeling For Bridge Assessment, Eugene J. Obrien, Bernard Enright, Abraham Getachew
Importance Of The Tail In Truck Weight Modeling For Bridge Assessment, Eugene J. Obrien, Bernard Enright, Abraham Getachew
Articles
To predict characteristic extreme traffic load effects, simulations are sometimes performed of bridge loading events. To generalize the truck weight data, statistical distributions are fitted to histograms of weight measurements. This paper is based on extensive WIM measurements from two European sites and shows the sensitivity of the characteristic traffic load effects to the fitting process. A semi-parametric fitting procedure is proposed: direct use of the measured histogram where there are sufficient data for this to be reliable and parametric fitting to a statistical distribution in the tail region where there are less data. Calculated characteristic load effects are shown …