scholarly journals The impact of bridge pier on ice jam evolution – an experimental study

2016 ◽  
Vol 64 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Jun Wang ◽  
Jian Hua ◽  
Jueyi Sui ◽  
Peng Wu ◽  
Tao Liu ◽  
...  
Keyword(s):  
Thickness Distribution ◽  
Early Spring ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Ice Jam ◽  
Laboratory Flume ◽  
Different Diameters ◽  
Hydraulic Process ◽  
Different Characteristics ◽  
The Impact

AbstractThe ice jam in a river can significantly change the flow field in winter and early spring. The presence of bridge piers further complicates the hydraulic process by interacting between the ice jam and bridge piers. Using the data collected from experiments in a laboratory flume, the evolution of an ice jam around bridge piers having three different diameters has been investigated in this study. Compared to results without-pier, it was found that the formation of an ice jam in the downstream of bridge pier is faster than that in the upstream. The thickness distribution of the ice jam shows clearly different characteristics in front and behind of bridge piers at different stages of the ice jam.

scholarly journals Analysis of Water Flow Pressure on Bridge Piers considering the Impact Effect

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Yin-hui Wang ◽  
Yi-song Zou ◽  
Lue-qin Xu ◽  
Zheng Luo
Keyword(s):  
Water Flow ◽  
Coupling Effect ◽  
Highway Bridges ◽  
Element Model ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Water Current ◽  
Fluid Structure ◽  
Impact Effect ◽  
The Impact

In order to investigate the effects of water current impact and fluid-structure interaction on the bridge piers, the mechanism of water flow impact on the bridge pier is firstly studied. Then a finite element model of a bridge pier is established including the effects of water flow impact as well as the water circumferential motion around the pier. Comparative study is conducted between the results of water impact effect, fluid-structure coupling effect, theoretical analysis, and also the results derived using the formulas specified in the design codes home and abroad. The results show that the water flow force calculated using the formulas provided by the codes should be multiplied by an impact amplifier to account for the effect of flood impact on the bridge pier. When the flood flows around the pier, the fluid-structure coupling effect on the bridge pier can be neglected. The method specified in the China guidelines ofGeneral Code for Design of Highway Bridges and Culvertstends to provide a larger result of the water flow force.

On the problem of using the bridge span as a tuned mass damper of bridge pier oscillation

2019 ◽  
pp. 24-30
Author(s):  
Olga Nesterova
Keyword(s):  
Critical Mass ◽  
Practical Importance ◽  
Tuned Mass Damper ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Optimal Parameters ◽  
Bridge Span ◽  
Mass Damper ◽  
Effective Use ◽  
The Impact

Objective: To identify the area of effective use of bridge span as a tuned mass damper of bridge pier oscillation during earthquake in seismic areas. Methods: Numerical simulation of oscillations of the “bridge pier with span” system under both the impact set by the harmonic rule and the records of past earthquake accelerograms. Results: The area of effective use of bridge span structures as a tuned mass damper of bridge piers’ oscillation during earthquake in seismic areas has been defined. The concept of the relative critical mass of the span used as a tuned mass damper of bridge piers’ oscillation during earthquake has been introduced. When the spun structure mass reaches the critical value, the effect of the tuned mass damper disappears. The dependences of the optimal parameters of the connection between the span and pier on the relative span mass used as a tuned mass damper have been obtained. It has been found that the span critical mass used as a tuned mass damper decreases when the pier damping increases, and the dependences of the optimal parameters of the connection between the span structure and the pier on the damping in the pier body have been obtained. Practical importance: The possibility of using span as a tuned mass damper of piers is shown. The optimum characteristics of the span and its connection with the pier body have been obtained to be used in designing. The use of span as a tuned mass damper in piers can significantly reduce labor input and the cost of bridge building in seismic areas. It also facilitates the elimination of consequences of devastating earthquakes.

scholarly journals Impacts of bridge piers on the initiation of ice cover – an experimental study

2015 ◽  
Vol 63 (4) ◽  
pp. 327-333 ◽  
Author(s):  
Jun Wang ◽  
Fayi Shi ◽  
Pangpang Chen ◽  
Peng Wu ◽  
Jueyi Sui
Keyword(s):  
Experimental Data ◽  
Ice Cover ◽  
Early Spring ◽  
Bridge Piers ◽  
Winter Period ◽  
Flow Conditions ◽  
Ice Jams ◽  
Ice Jam ◽  
Proposed Model ◽  
Northern Rivers

AbstractIce jams in northern rivers during winter period significantly change the flow conditions due to the extra boundary of the flow. Moreover, with the presence of bridge piers in the channel, the flow conditions can be further complicated. Ice cover often starts from the front of bridge piers, extending to the upstream. With the accumulation of ice cover, ice jam may happen during early spring, which results in the notorious ice jam flooding. In the present study, the concentration of flowing ice around bridge piers has been evaluated based on experiments carried out in laboratory. The critical condition for the initiation of ice cover around bridge piers has been investigated. An equation for the critical floe concentration was developed. The equation has been validated by experimental data from previous studies. The proposed model can be used for the prediction of formation of ice cover in front of a bridge pier under certain conditions.

scholarly journals Experimental Study of Inclined Bridge Pier Scouring

2020 ◽  
Vol 39 (4) ◽  
pp. 859-870
Author(s):  
Fakhar Muhammad Abbas ◽  
Usman Ali Naeem ◽  
Usman Ghani ◽  
Amina Khan ◽  
Talat Farid Ahmad
Keyword(s):  
Experimental Study ◽  
Inverse Relationship ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Clear Water ◽  
Lower Strength ◽  
Flow Rates ◽  
Laboratory Flume ◽  
Horseshoe Vortices

The bridges are one of important structures in any country. The failure of bridges occurs due to many factors including design flaws and manufacturing construction errors. Among all imperfections scouring around the pier is the most detrimental. So, the estimation of local scouring around a bridge pier is of fundamental importance for the safe design of bridges. Although numerous researches have been done on local scouring around a single bridge pier. The present study investigates the effect of angle of inclination of dual bridge pier configuration on local scouring around bridge piers. Principally rectangular shaped dual bridge piers were installed in sand bed of laboratory flume at angle of inclination of 0°,7°,12°,15° and 19° with vertical respectively. Three different flow rates 9, 14 and 18L/sec were considered during each trial. The duration of each trial was kept around 2 hours. The scour depth was measured separately around both piers with the help of point gauge under clear water condition. The value of scour depth around upstream pier was larger as compared to downstream pier because of the lower strength of horseshoe vortices around downstream pier. From the experimental results, it can be concluded that there is an inverse relationship between the angle of inclination and scour depth, an increase in the angle of inclination leads to decrease in scour depth around both piers. The value of scour depth was maximum when piers were at 0° and minimum at 19°. It was also found that scour depth increases with the increase in flow rate.

Numerical analysis of collision between a tractor-trailer and bridge pier

2018 ◽  
Vol 9 (4) ◽  
pp. 484-503 ◽  
Author(s):  
Luwei Chen ◽  
Hao Wu ◽  
Qin Fang ◽  
Tao Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Impact Force ◽  
Element Model ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Highway Bridge ◽  
Heavy Duty ◽  
The Impact ◽  
The Finite Element Model

Accidents involving collisions of heavy-duty trucks with highway bridge piers occurred occasionally, in which the bridge piers might be subjected to severe damage, and cause the collapse of the superstructure due to the loss of axial loading capacity. The existing researches are mostly concentrated on the light- or medium-duty trucks. This article mainly concerns about the collisions between the heavy-duty trucks (e.g. tractor-trailer) and bridge piers as well as the evaluation of the impact force. First, by modifying the finite element model of Ford F800 single-unit truck, which was developed by National Crash Analysis Center, the finite element model of a tractor-trailer is established. Then, the full-scale tractor-trailer crash test on concrete-filled steel pier jointly conducted by Texas Transportation Institute, Federal Highway Administration, and Texas Department of Transportation is numerically simulated. The impact process is well reproduced and the established model is validated by comparison of the impact force. It indicates that the tractor-trailer impact force time history consists of two or three peaks and the corresponding causes are revealed. Furthermore, the parametric influences on the impact force are discussed, including the diameter and cross section shape of the pier, cargo weight, impact velocity, relative impact position, and vehicle type. Finally, the finite element model of an actual reinforced concrete highway bridge pier is established, and the impact force and lateral displacement of the pier subjected to the impact of the tractor-trailer are numerically derived and discussed.

Impact of Chatbot in Transforming the Face of Retailing- An Empirical Model of Antecedents and Outcomes

2019 ◽  
Vol 12 ◽  
Author(s):  
Kumari Anshu ◽  
Loveleen Gaur ◽  
Arun Solanki
Keyword(s):  
Research Work ◽  
Shopping Behavior ◽  
Model Framework ◽  
Shopping Experience ◽  
The Face ◽  
Strongly Agree ◽  
Different Characteristics ◽  
Work Done ◽  
The Impact ◽  
Self Administered Questionnaire

Chatbot has emerged as a significant resolution to the swiftly growing customer caredemands in recent times. Chatbot has emerged as one of the biggest technological disruption. Simply speaking, it is a software agent facilitating interaction between computers and humans in natural language. So basically, it is a simulated, intellectual dialogue agent functional in a range of consumer engagement circumstances. It is the easiest and simplest means enable interaction between the retailers and the customers. </p><p> • Purpose- Most of the research work done in this field is concerned with their technical aspects. The recent research on chatbot pay little attention to the impact it is creating on users’ experience. Through this work, author is making an effort to know the customer-oriented impact that the chatbot bear on the shoppers. The purpose of this study is to develop and empirically test a framework that identify the customer oriented attributes of chatbot and impact of these attributes on customers. </p><p> • Objectives- The study intends to bridge the gap between concepts and actual attributes and applications on the subject of Chatbot. The following research objectives can address the various aspects of Chatbot affecting the different characteristics of consumers shopping behaviors: a) Identify the various attributes of chatbot that bears an impression on consumer shopping behavior. b) Evaluate the impact of chatbot on consumer shopping behavior that leads to the development of chatbot usage and adoption among the customer. </p><p> • Design/Methodology/Approach – For the purpose of analysis, author has administered Factor analysis and Multiple regression using SPSS version 23 for identification of various attributes of Chatbot and knowing their impact on shoppers. A self-administered questionnaire from the review of literature is developed. Industry experts in the field of retailing and academician evaluate the questionnaire. Primary information from the respondents is gathered using this questionnaire. The questionnaire comprises of Likert scale on a scale of 1 to 5 where 1 stands for strongly disagree and 5 stands for strongly agree. Data is collected from 126 respondents, out of which 111 respondents were finally considered for study and analysis purpose. </p><p> • Findings – The empirical results show that the study identifies various attributes of chatbot like Trust, Usefulness, Satisfaction, Readiness to Use and Accessibility. It is also found that chatbot is really influencing the customers in providing them with shopping experience, which can be very helpful to the businesses for increasing the sales and creating repurchase intention among the customers. </p><p> • Originality/value – The recent research on chatbot pay little attention to the impact it is creating on customers who are actually interacting with it on regular basis. The research paper extends information for understanding and appreciating the customer oriented attributes of artificially intelligent Chatbot. In this regard, the author has developed a model framework and proposed the attributes identified. Through the work, author is also making an effort to test empirically the impact of the identified attributes on the shoppers.

scholarly journals Time Granularity Impact on Propagation of Disruptions in a System-of-Systems Simulation of Infrastructure and Business Networks

2021 ◽  
Vol 18 (8) ◽  
pp. 3922
Author(s):  
Mateusz Iwo Dubaniowski ◽  
Hans Rudolf Heinimann
Keyword(s):  
Recovery Time ◽  
System Of Systems ◽  
Future Research ◽  
Business Networks ◽  
Simulation Experiments ◽  
Huge Impact ◽  
High Level ◽  
Systems Simulation ◽  
Different Characteristics ◽  
The Impact

A system-of-systems (SoS) approach is often used for simulating disruptions to business and infrastructure system networks allowing for integration of several models into one simulation. However, the integration is frequently challenging as each system is designed individually with different characteristics, such as time granularity. Understanding the impact of time granularity on propagation of disruptions between businesses and infrastructure systems and finding the appropriate granularity for the SoS simulation remain as major challenges. To tackle these, we explore how time granularity, recovery time, and disruption size affect the propagation of disruptions between constituent systems of an SoS simulation. To address this issue, we developed a high level architecture (HLA) simulation of three networks and performed a series of simulation experiments. Our results revealed that time granularity and especially recovery time have huge impact on propagation of disruptions. Consequently, we developed a model for selecting an appropriate time granularity for an SoS simulation based on expected recovery time. Our simulation experiments show that time granularity should be less than 1.13 of expected recovery time. We identified some areas for future research centered around extending the experimental factors space.

The flow characteristics around bridge piers under the impact of a ship

2020 ◽  
Vol 32 (6) ◽  
pp. 1165-1177
Author(s):  
Yan-fen Geng ◽  
Hua-qiang Guo ◽  
Xing Ke
Keyword(s):  
Flow Characteristics ◽  
Bridge Piers ◽  
The Impact

scholarly journals Simulation of Energy Absorption Performance of the Couplers in Urban Railway Vehicles during a Heavy Collision

Machines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 91
Author(s):  
Sunghyun Lim ◽  
Yong-hyeon Ji ◽  
Yeong-il Park
Keyword(s):  
Reaction Force ◽  
Crash Test ◽  
Railway Vehicle ◽  
Buffer System ◽  
Railway Vehicles ◽  
Hydraulic Shock Absorber ◽  
Coupling Buffer ◽  
Absorption Performance ◽  
Different Characteristics ◽  
The Impact

Railway vehicles are generally operated by connecting several vehicles in a row. Mechanisms connecting railway vehicles must also absorb front and rear shock loads that occur during a train’s operation. To minimize damage, rail car couplers are equipped with a buffer system that absorbs the impact of energy. It is difficult to perform a crash test and evaluate performance by applying a buffer to an actual railway vehicle. In this study, a simulation technique using a mathematical buffer model was introduced to overcome these difficulties. For this, a model of each element of the buffer was built based on the experimental data for each element of the coupling buffer system and a collision simulation program was developed. The buffering characteristics of a 10-car train colliding at 25 km/h were analyzed using a developed simulator. The results of the heavy collision simulation showed that the rubber buffer was directly connected to the hydraulic shock absorber in a solid contact state, and displacement of the hydraulic buffer hardly occurred despite the increase in reaction force due to the high impact speed. Since the impact force is concentrated on the vehicle to which the collision is applied, it may be appropriate to apply a deformation tube with different characteristics depending on the vehicle location.

scholarly journals The Impact of Microclimate on the Reproductive Phenology of Female Populus tomentosa in a Micro-Scale Urban Green Space in Beijing

2021 ◽  
Vol 13 (6) ◽  
pp. 3518
Author(s):  
Xiaoyi Xing ◽  
Li Dong ◽  
Cecil Konijnendijk ◽  
Peiyao Hao ◽  
Shuxin Fan ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Spatial Variation ◽  
Air Temperature ◽  
Green Space ◽  
Populus Tomentosa ◽  
Early Spring ◽  
Reproductive Phenology ◽  
Primary Role ◽  
Micro Scale ◽  
The Impact

The spatial variation of poplars’ reproductive phenology in Beijing’s urban area has aggravated the threat of poplar fluff (cotton-like flying seeds) to public health. This research explored the impact of microclimate conditions on the reproductive phenology of female Populus tomentosa in Taoranting Park, a micro-scale green space in Beijing (range <1 km). The observed phenophases covered flowering, fruiting, and seed dispersal, and ENVI-MET was applied to simulate the effect of the microclimate on SGS (start day of the growing season). The results showed that a significant spatial variation in poplar reproductive phenology existed at the research site. The variation was significantly affected by the microclimate factors DMT (daily mean temperature) and DMH (daily mean heat transfer coefficient), with air temperature playing a primary role. Specifically, the phenology of flowering and fruiting phenophases (BBB, BF, FF, FS) was negatively correlated with DMT (−0.983 ≤ r ≤ −0.908, p <0.01) and positively correlated with DMH (0.769 ≤ r ≤ 0.864, p < 0.05). In contrast, DSD (duration of seed dispersal) showed a positive correlation with DMT (r = 0.946, p < 0.01) and a negative correlation with DMH (r = −0.922, p < 0.01). Based on the findings, the increase in air convection with lower air temperature and decrease in microclimate variation in green space can be an effective way to shorten the seed-flying duration to tackle poplar fluff pollution in Beijing’s early spring.

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