Search results
1 – 10 of over 55000Saleh Abu Dabous and Sabah Alkass
A bridge network is a major capital asset that requires continuing investment in order to maintain the network within acceptable limits of safety and serviceability. Ranking and…
Abstract
Purpose
A bridge network is a major capital asset that requires continuing investment in order to maintain the network within acceptable limits of safety and serviceability. Ranking and prioritizing procedures have been widely used by several departments of transportation to select bridges for intervention and to distribute the available funds among competing projects. The available ranking and prioritizing procedures have various drawbacks, and an improved, rational ranking and prioritizing procedure is needed. The paper aims to address these issues.
Design/methodology/approach
The requirements and characteristics of an innovative ranking and prioritizing method are identified during interviews with professionals involved in bridge management. Based on these requirements, multi‐attribute utility theory (MAUT) is selected to develop the method. A technique to develop utility functions based on the analytical hierarchy process (AHP) is discussed. A hierarchy structure that captures the decision‐making elements is presented. A case study is used to demonstrate the applicability and the validity of the proposed ranking method.
Findings
The research findings have identified the decision objectives and the criteria essential to rank and prioritize bridge projects, and these are included within a framework to rank and prioritize bridge projects while incorporating experts' input in the process.
Practical implications
The proposed framework includes weights for the various objectives and recommends utility functions to evaluate the different attributes. In addition, the framework provides flexibility to adjust the weights and to modify the utility functions to reflect network‐specific characteristics. This method can be used by departments of transportation to rank bridges in a network, even incorporating conflicting criteria, and it can be integrated within an already implemented bridge management methodology.
Originality/value
Ranking and prioritizing projects are essential steps in bridge management. Current methods for ranking and prioritizing bridge projects are associated with various drawbacks. This paper proposes an innovative ranking method for bridge networks, based on MAUT. This theory provides flexibility for the decision makers in expressing their degree of satisfaction with each bridge attribute.
Details
Keywords
Infrastructure maintenance management has become a challenge field for civil engineers and government managers because of the increasing number of deteriorated structures, their…
Abstract
Infrastructure maintenance management has become a challenge field for civil engineers and government managers because of the increasing number of deteriorated structures, their complicated spatial locations, the improved service requirements, the limited maintenance budgets and so on. Therefore, maintenance management approaches have been developed for civil infrastructures such as bridges and roads over the past several decades, but most of such approaches focused on one specific structure only – project‐level maintenance management. Now, there are increasing demands and appropriate conditions for network‐level maintenance management for civil infrastructure systems. Aims to explore such a maintenance management approach by integrating and applying the current information technologies, which include the database management system, geographic information system, genetic algorithm and the Internet. Several possible applications of each technology are discussed for solving real‐world problems.
Details
Keywords
Pengfei Zheng and Gonglian Dai
This paper aims to obtain the further and overall generation about the static characteristics of the structure for the better application of the structure.
Abstract
Purpose
This paper aims to obtain the further and overall generation about the static characteristics of the structure for the better application of the structure.
Design/methodology/approach
Through nonlinear finite element simulation, serials of comparative analyses are performed on this structure and other three assumed structures, which illustrate the effect of the main part of the structure on the structural static properties. Meanwhile, adopting the first order method, spatial cable force optimization makes the structural mechanic more rational.
Findings
Under same level stress, this three‐main‐truss and three‐cable‐plane bridge could save almost 38.8 percent vertical chords materials consumption at least. In contrast, this bridge has a lower lateral torsional stiffness, considering the key to raise the lateral and torsional stiffness is enhancing axial stiffness of plane bracing, the suitable plane bracing members area is twice as the original area. After rational optimization, the cable tension ratio between the mid‐cable plane and the two side‐cable planes ranges from 1.09 to 1.14.
Originality/value
The work in this paper of the comparative analysis could give other engineers a way to a deep analysis method for the structural analysis, especially in civil engineering. The conclusions would provide other designers some applied advice.
Details
Keywords
Wessie W.S. Ling, Gail Taylor and M.T. Lo
Bridge lines represent a way for designers to expand their business, because typically designer merchandise is supplied to a limited number of stores. With bridge lines, the…
Abstract
Bridge lines represent a way for designers to expand their business, because typically designer merchandise is supplied to a limited number of stores. With bridge lines, the prices are lower and the line can be supplied to more stores. The bridge line market has been rapidly evolving in recent years. Retailers are paying close attention to this sector, particularly in the light of the stagnant demand for more expensive designer ready‐to‐wear collections. Despite the general economic recession, the culture of wearing fashion in the 1990s has paved the way to the growth of bridge lines.
Details
Keywords
Yong Bai, Seong Hoon Kim and William R. Burkett
The potential threats of extreme events to highway bridges have received increased attention from government agencies, the engineering and construction communities, and the…
Abstract
Purpose
The potential threats of extreme events to highway bridges have received increased attention from government agencies, the engineering and construction communities, and the traveling public. These events include terrorist attacks as well as human‐induced and natural hazards such as earthquakes, explosions, fires, floods, and hurricanes. To respond to the potential threats on highway bridges, a research project was conducted to identify rapid bridge replacement processes, techniques, and needs for improvements.
Design/methodology/approach
To achieve the research objectives, a detailed case study of previous bridge replacement following an extreme event was conducted. The case study was performed using a three‐step approach. First, the research team reviewed the literature related to the case. Second, the research team interviewed the people who were involved with the case via the telephone. Third, the research team conducted a written survey to gain knowledge about the previously unanswered questions and additional information related to the case.
Findings
After studying the case, lessons learned were identified first. Then, the research team determined the processes that were used in the rapid bridge replacements and the needed improvements so that the research community could investigate new technologies to advance current practices.
Originality/value
The lessons learned could be of benefit to government agencies who are responsible for development of the enhanced emergency response plans for highway bridges, and engineering and construction communities who are responsible for design and reconstruction of the damaged bridges. The development of new technologies, if successful, will ultimately enhance the capability of rapid bridge replacement after extreme events.
Details
Keywords
The purpose of this evaluative study is an attempt to understand the bridging programme by drawing on the work of Wadsworth and to prove that a place still exists for bridging…
Abstract
Purpose
The purpose of this evaluative study is an attempt to understand the bridging programme by drawing on the work of Wadsworth and to prove that a place still exists for bridging programmes within the University of Johannesburg and the higher education sector in South Africa.
Design/methodology/approach
The research study is both quantitative and qualitative in nature. An interpretative naturalistic approach is used to understand the thinking and experiences of the students in the bridging programme.
Findings
This study reveals, first that a causal relationship exists between the length of the bridging programme and how long students take to successfully complete the national diploma in engineering. Second, that bridging programmes can contribute to the success of engineering students who want to successfully complete their engineering studies within the designated timespan. Third, that, if designated staff are utilized in the teaching of the bridging programmes, students are able to receive the necessary support which enables them to successfully complete the national diploma in engineering.
Originality/value
This research reveals that bridging programmes, implemented over an extended period, are valuable because they allow student access to higher education and lay a solid foundation by equipping them with the knowledge and skills necessary for success in mainstream diplomas such as the national diploma in engineering. These programmes put into practice the shift of policy emphasis from “access” to “success”, which has implications not only for the University of Johannesburg but also for the higher education sector in South Africa.
Details
Keywords
Tadashi Takemoto, Tatsuya Funaki, Makoto Miyazaki and Akira Matsunawa
Establishes a quantitative evaluation method on solder bridging in microsoldering using a printed wiring board with comb pattern conductors. Bridge tests were conducted by…
Abstract
Establishes a quantitative evaluation method on solder bridging in microsoldering using a printed wiring board with comb pattern conductors. Bridge tests were conducted by immersing the comb pattern board into a molten solder bath. The total length of solder bridge between conductors against the total length between conductors was measured as a measure of the occurrence of solder bridging. The occurrence of bridging depended on the number of immersions, flux activity including solid content, conductor spacing, solder bath temperature and solder composition. The increase in number of immersion enhanced bridging. The rosin flux without activators showed higher bridging than the activated flux. Sn‐37Pb solder showed lower bridging than Sn‐3.5Ag‐5Bi solder. Solder bridging was found to be closely correlated with wettability, therefore, the improvement of wettability could be effective to suppress solder bridging. The proposed method is believed to be suitable for the quantitative evaluation of solder bridging.
Details
Keywords
This study focuses on the triadic multilevel psychic distance (MPD) between the firm, target market and bridge-maker and its consequences for firm internationalization…
Abstract
Purpose
This study focuses on the triadic multilevel psychic distance (MPD) between the firm, target market and bridge-maker and its consequences for firm internationalization. Specifically, it spotlights the triadic psychic distance between firms, the levels of psychic distance in the target market (country and business) and the bridge-maker. Therefore, this study examines the triadic MPD among these three entities and its impact on firm internationalization.
Design/methodology/approach
This study uses qualitative and case study research approaches. It is based on 8 case companies and 24 internationalization cases. Secondary data were collected, and interviews with bridge-makers and industry experts were conducted.
Findings
The study found that MPD appeared in the triad. The MPD between firms and markets is related to country-specific differences and business difficulties. The MPD between the firm and the bridge-maker is based on the latter’s lack of knowledge vis-à-vis bridging the firm’s MPD. Finally, the MPD between bridge-makers and the market is based on the former’s lack of knowledge of the home country’s business difficulties.
Originality/value
This is the first study to develop and adopt a triadic multilevel psychic distance conceptualization that provides evidence for and sheds light on the triadic MPD and its effect on firm internationalization. This study identifies the reasons behind triadic MPD in connection to firm internationalization. Notably, firm internationalization is interdependent on the triadic MPD setting between the firm, bridge-maker and target market. It has theoretical value and contributes to the recent advancement in the understanding of MPD in international marketing literature.
Details
Keywords
Diego Gabriel Metz, Roberto Dalledone Machado, Marcos Arndt and Carlos Eduardo Rossigali
Realistic composite vehicles with 2, 3, 5 and 9 axles, consisting of a truck with one or two trailers, are addressed in this paper by computational models for vehicle–bridge…
Abstract
Purpose
Realistic composite vehicles with 2, 3, 5 and 9 axles, consisting of a truck with one or two trailers, are addressed in this paper by computational models for vehicle–bridge interaction analysis.
Design/methodology/approach
The vehicle–bridge interaction (VBI) models are formed by sets of 2-D rigid blocks interconnected by mass, damping and stiffness elements to simulate their suspension system. The passage of the vehicles is performed at different speeds. Several rolling surface profiles are admitted, considering the maintenance grade of the pavement. The spectral density functions are generated from an experimental database to form the longitudinal surface irregularity profiles. A computational code written in Phyton based on the finite element method was developed considering the Euler–Bernoulli beam model.
Findings
Several models of composite heavy vehicles are presented as manufactured and currently travel on major roads. Dynamic amplification factors are presented for each type of composite vehicle.
Research limitations/implications
The VBI models for compound heavy vehicles are 2-D.
Social implications
This work contributes to improving the safety and lifetime of the bridges, as well as the stability and comfort of the vehicles when passing over a bridge.
Originality/value
The structural response of the bridge is affected by the type and size of the compound vehicles, their speed and the conservative grade of the pavement. Moreover, one axle produces vibrations that can be superposed by the vibrations of the other axles. This effect can generate not usual dynamic responses.
Details
Keywords
Hongping Xing, Yu Liu and Xiaodan Sun
The smoothness of the high-speed railway (HSR) on the bridge may exceed the allowable standard when an earthquake causes vibrations for HSR bridges, which may threaten the safety…
Abstract
Purpose
The smoothness of the high-speed railway (HSR) on the bridge may exceed the allowable standard when an earthquake causes vibrations for HSR bridges, which may threaten the safety of running trains. Indeed, few studies have evaluated the exceeding probability of rail displacement exceeding the allowable standard. The purposes of this article are to provide a method for investigating the exceeding probability of the rail displacement of HSRs under seismic excitation and to calculate the exceeding probability.
Design/methodology/approach
In order to investigate the exceeding probability of the rail displacement under different seismic excitations, the workflow of analyzing the smoothness of the rail based on incremental dynamic analysis (IDA) is proposed, and the intensity measure and limit state for the exceeding probability analysis of HSRs are defined. Then a finite element model (FEM) of an assumed HSR track-bridge system is constructed, which comprises a five-span simply-supported girder bridge supporting a finite length CRTS II ballastless track. Under different seismic excitations, the seismic displacement response of the rail is calculated; the character of the rail displacement is analyzed; and the exceeding probability of the rail vertical displacement exceeding the allowable standard (2mm) is investigated.
Findings
The results show that: (1) The bridge-abutment joint position may form a step-like under seismic excitation, threatening the running safety of high-speed trains under seismic excitations, and the rail displacements at mid-span positions are bigger than that at other positions on the bridge. (2) The exceeding probability of rail displacement is up to about 44% when PGA = 0.01g, which is the level-five risk probability and can be described as 'very likely to happen'. (3) The exceeding probability of the rail at the mid-span positions is bigger than that above other positions of the bridge, and the mid-span positions of the track-bridge system above the bridge may be the most hazardous area for the running safety of trains under seismic excitation when high-speed trains run on bridges.
Originality/value
The work extends the seismic hazardous analysis of HSRs and would lead to a better understanding of the exceeding probability for the rail of HSRs under seismic excitations and better references for the alert of the HSR operation.
Details