scholarly journals A Methodology for Multihazards Load Combinations of Earthquake and Heavy Trucks for Bridges

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Dezhang Sun ◽  
Xu Wang ◽  
Baitao Sun
Keyword(s):  
Random Process ◽  
Random Variables ◽  
Load Resistance ◽  
Time Interval ◽  
Modified Model ◽  
Heavy Trucks ◽  
Extreme Load ◽  
Earthquake Load ◽  
Heavy Truck ◽  
Truck Load

Issues of load combinations of earthquakes and heavy trucks are important contents in multihazards bridge design. Currentload resistance factor design(LRFD)specificationsusually treat extreme hazards alone and have no probabilistic basis in extreme load combinations. Earthquake load and heavy truck load are considered as random processes with respective characteristics, and the maximum combined load is not the simple superimposition of their maximum loads. Traditional Ferry Borges-Castaneda model that considers load lasting duration and occurrence probability well describes random process converting to random variables and load combinations, but this model has strict constraint in time interval selection to obtain precise results. Turkstra’s rule considers one load reaching its maximum value in bridge’s service life combined with another load with its instantaneous value (or mean value), which looks more rational, but the results are generally unconservative. Therefore, a modified model is presented here considering both advantages of Ferry Borges-Castaneda's model and Turkstra’s rule. The modified model is based on conditional probability, which can convert random process to random variables relatively easily and consider the nonmaximum factor in load combinations. Earthquake load and heavy truck load combinations are employed to illustrate the model. Finally, the results of a numerical simulation are used to verify the feasibility and rationality of the model.

scholarly journals Study Based on Bridge Health Monitoring System on Multihazard Load Combinations of Earthquake and Truck Loads for Bridge Design in the Southeast Coastal Areas of China

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Dezhang Sun ◽  
Bin Chen ◽  
Baitao Sun
Keyword(s):  
Monitoring System ◽  
Health Monitoring ◽  
Coastal Areas ◽  
Time Interval ◽  
Bridge Design ◽  
Probability Curve ◽  
Health Monitoring System ◽  
Bridge Health Monitoring ◽  
Earthquake Load ◽  
Truck Load

Similar to AmericanLRFD Bridge Design Specifications, the current Chinese bridge design code is fully calibrated against gravity load and live load. Earthquake load is generally considered alone and has its own methodology, however, which is not covered in the code in a consistent probability-based fashion. Earthquake load and truck load are the main loads considered in the basis of bridge design in more than 70% of seismic areas in China. They are random processes, and their combination is the main subject of this paper. Seismic characteristics of southeast coastal areas of China are discussed and an earthquake probability curve is calculated through seismic risk analysis. Using measured truck load data from a Bridge Health Monitoring System, the multimodal characteristics of truck load are analyzed and a probability model for a time intervaltis obtained by fitting results and reliability theory. Then, a methodology is presented to combine earthquake load and truck load on a probabilistic basis. To illustrate this method, truck load and earthquake load combinations are used. Results conceptually illustrate that truck load and earthquake load are not dominant in southeast coastal areas of China, but the effect of their combination is. This methodology quantitatively demonstrates that the design is controlled by truck load in most ranges; that is, truck load is more important to bridge design in the region.

scholarly journals Period-Life of a Branching Process with Migration and Continuous Time

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 868
Author(s):  
Khrystyna Prysyazhnyk ◽  
Iryna Bazylevych ◽  
Ludmila Mitkova ◽  
Iryna Ivanochko
Keyword(s):  
Random Process ◽  
Generating Function ◽  
Continuous Time ◽  
Branching Process ◽  
Probability Generating Function ◽  
Time Interval ◽  
The Moment ◽  
First Time ◽  
Critical Branching Process ◽  
Number Of Particles

The homogeneous branching process with migration and continuous time is considered. We investigated the distribution of the period-life τ, i.e., the length of the time interval between the moment when the process is initiated by a positive number of particles and the moment when there are no individuals in the population for the first time. The probability generating function of the random process, which describes the behavior of the process within the period-life, was obtained. The boundary theorem for the period-life of the subcritical or critical branching process with migration was found.

scholarly journals Improved bounds for the availability and unavailability in a fixed time interval for systems of maintained, interdependent components

1980 ◽  
Vol 12 (01) ◽  
pp. 200-221 ◽  
Author(s):  
B. Natvig
Keyword(s):  
Lower Bound ◽  
System Reliability ◽  
Nuclear Reactors ◽  
Random Variables ◽  
Fixed Time ◽  
Time Interval ◽  
Coherent System ◽  
Exact Results ◽  
Fixed Time Interval ◽  
Special Case

In this paper we arrive at a series of bounds for the availability and unavailability in the time interval I = [t A , t B ] ⊂ [0, ∞), for a coherent system of maintained, interdependent components. These generalize the minimal cut lower bound for the availability in [0, t] given in Esary and Proschan (1970) and also most bounds for the reliability at time t given in Bodin (1970) and Barlow and Proschan (1975). In the latter special case also some new improved bounds are given. The bounds arrived at are of great interest when trying to predict the performance process of the system. In particular, Lewis et al. (1978) have revealed the great need for adequate tools to treat the dependence between the random variables of interest when considering the safety of nuclear reactors. Satyanarayana and Prabhakar (1978) give a rapid algorithm for computing exact system reliability at time t. This can also be used in cases where some simpler assumptions on the dependence between the components are made. It seems, however, impossible to extend their approach to obtain exact results for the cases treated in the present paper.

scholarly journals Reliability-Based Safety Evaluation of the BISTOON Historic Masonry Arch Bridge

2020 ◽  
Vol 30 (1) ◽  
pp. 87-110 ◽  
Author(s):  
Majid Pouraminian ◽  
Somayyeh Pourbakhshian ◽  
Ehsan Noroozinejad Farsangi ◽  
Sevil Berenji ◽  
Salman Keyani Borujeni ◽  
...  
Keyword(s):  
Probabilistic Analysis ◽  
Safety Evaluation ◽  
Random Variables ◽  
Load Resistance ◽  
Maximum Tensile Stress ◽  
Safety Index ◽  
Limit States ◽  
Masonry Arch ◽  
Arch Bridge ◽  
Historic Masonry

AbstractThis research examines the probabilistic safety assessment of the historic BISTOON arch bridge. Probabilistic analysis based on the Load-Resistance model was performed. The evaluation of implicit functions of load and resistance was performed by the finite element method, and the Monte-Carlo approach was used for experiment simulation. The sampling method used was Latin Hypercube. Four random variables were considered including modulus of elasticity of brick and infilled materials and the specific mass of brick and infilled materials. The normal distribution was used to express the statistical properties of the random variables. The coefficient of variation was defined as 10%. Linear behavior was assumed for the bridge materials. Three output parameters of maximum bridge displacement, maximum tensile stress, and minimum compressive stress were assigned as structural limit states. A sensitivity analysis for probabilistic analysis was performed using the Spearman ranking method. The results showed that the sensitivity of output parameters to infilled density changes is high. The results also indicated that the system probability of failure is equal to p fsystem =1.55 × 10−3. The bridge safety index value obtained is βt = 2.96, which is lower than the recommended target safety index. The required safety parameters for the bridge have not been met and the bridge is at the risk of failure.

Predicting Truck Load Variation Using Q-Truck Model

2014 ◽  
Vol 534 ◽  
pp. 105-110
Author(s):  
Rosnawati Buhari ◽  
Mohd Ezree Abdullah ◽  
Munzilah Md Rohani
Keyword(s):  
Asphalt Concrete ◽  
Radial Strain ◽  
Suspension System ◽  
Vehicle Speed ◽  
Pavement Distress ◽  
Traffic Loads ◽  
Road Roughness ◽  
Heavy Truck ◽  
Truck Load ◽  
Pavement Damage

The study of heavy vehicle forces on pavement is important for both vehicle and pavement. Indeed it was identified several factors such as environment, materials and design consideration affects pavement damage over time with traffic loads playing a key role in deterioration. Therefore, this paper presents dynamically varying tire pavement interaction load, thus enable to assess the strain response of pavements influenced by road roughness, truck suspension system, variation of axle loading and vehicle speed. A 100m pavement with good evenness was simulated to check the sensitivity of the dynamic loads and heavy truck vertical motions to the roughness. The most important performance indicators that are required in pavement distress evaluation are radial strain at the bottom of the asphalt concrete and vertical strain at the subgrade surface was predicted using peak influence function approach. The results show that truck speed is the most important variables that interact with truck suspension system and thus effect of loading time are extremely important when calculating the critical.

scholarly journals Enterprise growth simulation model

2020 ◽  
Vol 175 ◽  
pp. 12006 ◽  
Author(s):  
Ilona Avlasenko ◽  
Lyudmila Avlasenko ◽  
Isa Peshkhoev ◽  
Yuri Podkolzin ◽  
Oksana Savelyeva
Keyword(s):  
Simulation Model ◽  
Random Process ◽  
Random Function ◽  
Statistical Tests ◽  
Random Variables ◽  
Small Enterprise ◽  
Working Capital ◽  
Loan Rate ◽  
Probability Of Bankruptcy ◽  
Annual Working

Simulation mathematical model of small enterprise functioning is under analysis in this article. It is assumed that annual working capital profitability and loan rate are random variables with normal distribution, the amount of borrowed capital does not exceed the amount of own working capital. Given the value of its working capital at the beginning of time, its dependence on time is constructed as a random process. The parameters of random variables are estimated based on the processing of statistical data on the previous activities of this enterprise. The implementation of the random process is statistically modeled. With the help of the statistical tests, implementations of random function of growth of own working capital are built and the probability of bankruptcy is estimated as relative frequency of cases of adoption of negative value by random function. It is proposed to use the built simulation model of the enterprise to estimate the probability of bankruptcy of the studied enterprise in the coming period (a given number ofyears).

Investigation of Tack Coat Bond Damage Mechanism in Asphalt Surfaced Pavements under Dynamic Truck Loads

2020 ◽  
Vol 2674 (3) ◽  
pp. 317-328
Author(s):  
Mostafa Estaji ◽  
Erdem Coleri ◽  
Blaine Wruck
Keyword(s):  
Structural Integrity ◽  
Moving Load ◽  
Damage Mechanism ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Load Models ◽  
Tack Coat ◽  
Heavy Truck ◽  
Truck Load ◽  
The Impact

Bonding created by the tack coat allows the pavement system to carry heavy truck loads as a monolithic structure and improves the structural integrity. In Oregon and throughout the U.S.A., CSS-1H is the most commonly used tack coat type. However, field observations have revealed that new engineered tack coats, although more expensive, outperform the conventional types in relation to shear resistance. In this study, the impact of these new engineered emulsions on in-situ bond performance was quantified by laboratory testing and numerical modeling. Bonding damage performance of all tack coats was experimentally determined by using direct shear tests. Full-scale moving truck load models were developed and calibrated using the load-displacement parameters obtained from the laboratory shear tests. The impact of adverse construction conditions, such as dust, rain, and tack coat coverage, on tack coat bond damage under heavy truck loads was determined. It was concluded that the presence of dust had relatively the lowest contribution to shear damage. Rain during construction had the highest impact on the damage behavior and tack coat application on a wet surface increases the potential for damage by 20.1%. A 50% coverage of tack coat during construction resulted in 12.8% higher damage levels compared with 100% tack coat coverage of the surface area. Moving load models for heavy trucks caused 2.44 times more bonding damage at the bonded interface compared with the damage created by smaller trucks (F450).

Sign in / Sign up

Export Citation Format

Share Document