Research on Failure Probability of Load-Carrying Capacity for Existing Diseased Concrete Bridge

As a bridge assessment method, risk assessment is more and more applied to load-carrying capacity assessment of existing bridge. This method assesses the bridge through the failure risk value which calculated by the failure probability and failure loss value. The most important factor to the risk assessment of load-carrying capacity upon the existing and diseased bridge is the calculation of failure probability. This paper combines the reliability calculation theory with a certain site detective data of bridge that considering uncertainty of load and resistance along with the diseases of bridge, and induces in the correction coefficient of load and resistance respectively to calculate the failure probability and reliability index of bridge. Finally, these indexes are compared with those provided by the current code to implement risk assessment of load-carrying capacity of the bridge.

Download Full-text

Assessment of Load Carrying Capacity for Concrete Rectangle Section Simple Beam Subjected to Fire

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.2841 ◽

2012 ◽

Vol 204-208 ◽

pp. 2841-2845

Author(s):

Gang Zhang ◽

Shuan Hai He ◽

Hong Jun Guo

Keyword(s):

Fire Resistance ◽

Carrying Capacity ◽

Concrete Beam ◽

Fire Hazard ◽

Assessment Method ◽

Concrete Cover ◽

Load Carrying Capacity ◽

Load Carrying ◽

Cover Thickness ◽

Beam Bridge

The assessment method of load carrying capacity for concrete rectangle section simple beam subjected to fire was presented. Comprehensively considering influencing parameters, load carrying capacity for reinforced concrete rectangle section simple beam was analyzed in a fire hazard by using numerical simulation program. A series of safety assessment regularities for the reinforcement pieces was put forward subjected to fire. The studied results indicate that: the ultimate moment for reinforcement concrete beam bridge tends to decrease linearly after 40 minute, the fire resistance of the reinforcement concrete rectangle section simple beam increase linearly with the increment of the concrete cover thickness; Therefore, the increment of concrete protective thickness is effective to fire resistance and safety grade for the reinforcement concrete beam.

Download Full-text

Reliability-based load-carrying capacity assessment of bridges using structural health monitoring and nonlinear analysis

Structural Health Monitoring ◽

10.1177/1475921718808462 ◽

2018 ◽

Vol 18 (1) ◽

pp. 20-34 ◽

Cited By ~ 5

Author(s):

Shojaeddin Jamali ◽

Tommy HT Chan ◽

Andy Nguyen ◽

David P Thambiratnam

Keyword(s):

Structural Health Monitoring ◽

Health Monitoring ◽

Carrying Capacity ◽

Assessment Procedure ◽

Load Rating ◽

Load Carrying Capacity ◽

Structural Health ◽

Load Carrying ◽

Existing Bridges ◽

Bridge Assessment

For assessment of existing bridges, load rating is usually performed to assess the capacity against vehicular loading. Codified load rating can be conservative if the rating is not coupled with the field data or if simplifications are incorporated into assessment. Recent changes made to the Australian Bridge assessment code (AS 5100.7) distinguish the difference between design and assessment requirements, and include addition of structural health monitoring for bridge assessment. However, very limited guidelines are provided regarding higher order assessment levels, where more refined approaches are required to optimize the accuracy of the assessment procedure. This article proposes a multi-tier assessment procedure for capacity estimation of existing bridges using a combination of structural health monitoring techniques, advanced nonlinear analysis, and probabilistic approaches to effectively address the safety issues on aging bridges. Assessment of a Box Girder bridge was carried out according to the proposed multi-tier assessment, using data obtained from modal and destructive testing. Results of analysis at different assessment tiers showed that both load-carrying capacity and safety index of the bridge vary significantly if current bridge information is used instead of as-designed bridge information. Findings emerged from this study demonstrated that accuracy of bridge assessment is significantly improved when structural health monitoring techniques along with reliability approaches and nonlinear finite element analysis are incorporated, which will have important implications that are relevant to both practitioners and asset managers.

Download Full-text

Analysis of the Implied Reliability Index and Load and Resistance Coefficients for China’s Current Highway Bridge Load-Carrying Capacity Evaluation Code

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.578-579.1512 ◽

2014 ◽

Vol 578-579 ◽

pp. 1512-1521

Author(s):

Yan Ling Leng ◽

Jin Quan Zhang ◽

Rui Nian Jiang

Keyword(s):

Carrying Capacity ◽

Reliability Index ◽

Highway Bridges ◽

Load Carrying Capacity ◽

Evaluation Code ◽

Reliability Level ◽

Capacity Evaluation ◽

Load Carrying ◽

Resistance Coefficients ◽

Current Code

China’s current load-carrying capacity evaluation code for highway bridges is a semi reliability-based code. The reliability level of the code is analyzed through a comparative study, and methods used to update the reliability level of this code are specified in this paper. A formula to calculate the implied reliability index is proposed and verified by comparison with calibrated reliability indexes in design codes. Then the formula is used to calculate the implied reliability index with statistical parameters derived from the load and resistance coefficients in the current code. It is proposed that the implied reliability index should be adjusted by considering historical failure rates. Different criteria used to define historical failure rates of highway bridges are discussed. In addition, the paper compares the reliability level, applicability, evaluation frequency, target reliability indexes, and resistance and load coefficients between AASHTO and China’s current code. The paper would serve as a reference for the upcoming research on the updating of current highway bridge Load-carrying capacity evaluation code.

Download Full-text

Influence of Yield Strength Variability over Cross-Section to Steel Beam Load-Carrying Capacity

Nonlinear Analysis Modelling and Control ◽

10.15388/na.2005.10.2.15129 ◽

2005 ◽

Vol 10 (2) ◽

pp. 151-160 ◽

Cited By ~ 3

Author(s):

J. Kala ◽

Z. Kala

Keyword(s):

Yield Strength ◽

Cross Section ◽

Carrying Capacity ◽

Bending Moment ◽

Statistical Characteristics ◽

Load Carrying Capacity ◽

Load Carrying ◽

Strength Variability ◽

Hot Rolled ◽

Hot Rolled Steel

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.

Download Full-text

Fuzzy Sets Theory in Comparison with Stochastic Methods to Analyse Nonlinear Behaviour of a Steel Member under Compression

Nonlinear Analysis Modelling and Control ◽

10.15388/na.2005.10.1.15135 ◽

2005 ◽

Vol 10 (1) ◽

pp. 65-75 ◽

Cited By ~ 5

Author(s):

Z. Kala

Keyword(s):

Fuzzy Sets ◽

Carrying Capacity ◽

Stochastic Methods ◽

Nonlinear Behaviour ◽

Load Carrying Capacity ◽

Load Carrying ◽

Input Parameters ◽

Stochastic Solution ◽

Fuzzy Solution ◽

Sets Theory

The load-carrying capacity of the member with imperfections under axial compression is analysed in the present paper. The study is divided into two parts: (i) in the first one, the input parameters are considered to be random numbers (with distribution of probability functions obtained from experimental results and/or tolerance standard), while (ii) in the other one, the input parameters are considered to be fuzzy numbers (with membership functions). The load-carrying capacity was calculated by geometrical nonlinear solution of a beam by means of the finite element method. In the case (ii), the membership function was determined by applying the fuzzy sets, whereas in the case (i), the distribution probability function of load-carrying capacity was determined. For (i) stochastic solution, the numerical simulation Monte Carlo method was applied, whereas for (ii) fuzzy solution, the method of the so-called α cuts was applied. The design load-carrying capacity was determined according to the EC3 and EN1990 standards. The results of the fuzzy, stochastic and deterministic analyses are compared in the concluding part of the paper.

Download Full-text

Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

Tire Science and Technology ◽

10.2346/1.2174344 ◽

2005 ◽

Vol 33 (4) ◽

pp. 210-226 ◽

Cited By ~ 6

Author(s):

I. L. Al-Qadi ◽

M. A. Elseifi ◽

P. J. Yoo ◽

I. Janajreh

Keyword(s):

Carrying Capacity ◽

Material Properties ◽

Three Dimensional ◽

Fe Analysis ◽

Load Carrying Capacity ◽

Inflation Pressure ◽

3D Finite Element ◽

Load Carrying ◽

Pavement Damage ◽

New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

Download Full-text