Design parameters of suspension bridges: Updates of state of art and its application on multi-span typology

2015 ◽  
pp. 519-526 ◽  
Keyword(s):  
Design Parameters ◽  
Suspension Bridges ◽  
State Of Art

Building 8500+ Trail Bridges in the Himalayas

2021 ◽  
Author(s):  
Robert Groeli
Keyword(s):  
International Development ◽  
Technical Assistance ◽  
Local Level ◽  
Cost Effective ◽  
Suspension Bridge ◽  
Development Cooperation ◽  
Design Parameters ◽  
Suspension Bridges ◽  
Teaching Resources ◽  
Economic Output

<p>Mobility is one of the most challenging fundamentals of rural livelihood in the Himalayan hills and mountains. More than 8500 trail bridges, comprising an overall span-length of about 650 kilometers have been constructed to date, saving millions of walking hours for people living in the rural Himalayan areas. Previously, crossing rivers was dangerous and sometimes impossible, especially in the rainy season. These bridges created vital connections which enabled children to go to school and people to access public services and visit medical centers and sanctuaries. They also boost local economic output by reducing the effort required to run local farms, gather crops and visit regional markets.</p><p>Fig. 1:The struggles and dangers of crossing a river and its solution</p><p>Swiss technical assistance for rural trail bridges started in the early sixties with the construction of a few suspension bridges in the hill areas of Nepal. In 1964 the Nepalese Government established the Suspension Bridge Division (SBD), and starting in 1972 the Swiss Government began providing continuous technical and financial assistance. Similarly, the Public Works Department in Bhutan initiated a country wide trail bridge construction program in 1971 for which assistance was provided from 1985-2010. Exchanges of experiences between these programs created a collaborative environment where new ideas could be evaluated and tested in the field. After SBD initially developed the basic technical norms, design parameters and standard designs suitable for long-span bridges, demand for simpler shorter span bridges rose tremendously. This prompted the program to develop “community executable bridge designs” adapted to the local skills and materials while conforming to established engineering standards. As a result, cost-effective, easy to implement technologies and community-based approaches were developed, which have been replicated in numerous countries leading to multiple successful partnerships in international development cooperation.</p><p>The purpose of this paper is to highlight the following outcomes of the trail bridge-program:</p><ul><li><p>Standardized cost-effective trail bridge designs based on local capabilities and bridge-building techniques</p></li><li><p>Published of manuals, technical drawings and teaching resources for design, construction and fabrication</p></li><li><p>Engaged local communities in the construction, operation and maintenance of trail bridges</p></li><li><p>Compiled comprehensive trail bridge directory for planning, monitoring and maintenance</p></li><li><p>Established Sector Wide Approach (SWAp) with institutional frameworks at national and local level</p></li><li><p>‘South-South Cooperation’ with Bhutan, Tanzania, Ethiopia, Indonesia, Laos, Burundi, Honduras, Guatemala</p></li></ul>

scholarly journals Influence of catwalk design parameters on the galloping of constructing main cables in long-span suspension bridges

2017 ◽  
Vol 19 (6) ◽  
pp. 4671-4684 ◽  
Author(s):  
Shengli Li ◽  
Pan Guo ◽  
Chaoqun Wang ◽  
Yanan Hu ◽  
Dongwei Wang
Keyword(s):  
Design Parameters ◽  
Suspension Bridges ◽  
Long Span ◽  
Main Cables

scholarly journals Arranging Parameters of Self-anchored Stressed Ribbon Supported on Arch Pedestrian Bridges

2017 ◽  
Vol 9 (5) ◽  
pp. 495-499 ◽  
Author(s):  
Vilius Karieta
Keyword(s):  
Twentieth Century ◽  
Construction Cost ◽  
Computational Scheme ◽  
Design Parameters ◽  
Suspension Bridges ◽  
Pedestrian Bridges ◽  
Major Disadvantage ◽  
Arch Structure ◽  
Support Reactions ◽  
Horizontal Support

Stressed ribbon pedestrian bridges are most graceful, efficient and economical strains of suspension bridges. However, these structures have a major disadvantage – very large horizontal support reactions, which result mainly to the construction cost. In order to discover new forms and to extend the limits of stressed ribbon bridges, in the end of twentieth century these constructions were started to combine with other bearing elements in cable­stayed, under­deck cable­stayed bridges and other structures. At the beginning of the twenty­first century stressed ribbon supported on arch structure was discovered. The paper presents reviews of suspension supported on arch footbridges and classification. Considered the main geometrical design parameters and their interdependence. The paper presents a method of how to balance self­anchored suspension supported on arch bridge design computational scheme.

Post-Critical Behavior of Suspension Bridges Under Nonlinear Aerodynamic Loading

2015 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Arena ◽  
Walter Lacarbonara ◽  
Pier Marzocca
Keyword(s):  
Reduction Process ◽  
Design Parameters ◽  
Suspension Bridges ◽  
Long Span ◽  
Fold Bifurcation ◽  
Speed Up ◽  
The Stability ◽  
Parametric Analyses ◽  
Bifurcation Behavior ◽  
Nonlinear Aerodynamic

The limit cycle oscillations (LCOs) exhibited by long-span suspension bridges in post-flutter condition are investigated. A parametric dynamic model of prestressed long-span suspension bridges is coupled with a nonlinear quasi-steady aerodynamic formulation to obtain the governing aeroelastic partial differential equations adopted herewith. By employing the Faedo–Galerkin method, the aeroelastic nonlinear equations are reduced to their state-space ordinary differential form. Convergence analysis for the reduction process is first carried out and time-domain simulations are performed to investigate LCOs while continuation tools are employed to path follow the post-critical LCOs. A supercritical Hopf bifurcation behavior, confirmed by a stable LCO, is found past the critical flutter condition. The analysis shows that the LCO amplitude increases with the wind speed up to a secondary critical speed where it terminates with a fold bifurcation. The stability of the LCOs within the range bracketed by the Hopf and fold bifurcations is evaluated by performing parametric analyses regarding the main design parameters that can be affected by uncertainties, primarily the structural damping and the initial wind angle of attack.

A Review of the State of Art in Heat Sealing of Multilayer Polymer Films

2017 ◽  
Author(s):  
Jorge Enrique Uribe Juárez ◽  
Alejandro C. Ramírez-Reivich ◽  
Crisanto Mendoza Covarrubias ◽  
Ma. del Pilar Corona-Lira
Keyword(s):  
Polymer Films ◽  
Theoretical Basis ◽  
Temperature Gradients ◽  
Design Parameters ◽  
Uniform Pressure ◽  
Operating Characteristics ◽  
Production Lines ◽  
Seal Integrity ◽  
Thermal Phase ◽  
State Of Art

All sealing technologies present inconveniences to be solved. One of the most significant adverse effects in the sealing production lines is the amount of material waste that is genetated due to the difficulties of achieving the correct thermal phase change in the polymer film during the sealing process. Sealing methods such as Induction, ultrasonic or heated jaw have similar operating characteristics, minimum gradients in pressure and temperature that are nedeed to create an efficient polymer transition, to produce the correct molecular arrangements and to avoid zones with little or null interaction between melted surfaces. This review shows the factors that affect the performance of jaw-multilayer polymer films that produce bad seal integrity; through understanding the design parameters to generate a small pressure and temperature gradients also characterizing and testing this phenomenon, the result of the review will help to identify theoretical basis and opportunities to design an innovate heated jaw sealing system with a uniform pressure and temperature along the sealing area.

scholarly journals Effect of Modification of Deck Properties on Suspension Bridges

2017 ◽  
Vol 12 (1) ◽  
pp. 39-50
Author(s):  
Jagat Kumar Shrestha
Keyword(s):  
Three Dimensional ◽  
Suspension Bridge ◽  
Design Parameters ◽  
Suspension Bridges ◽  
Finite Element Models ◽  
Real World Problem ◽  
Dimensional Finite Element ◽  
Design Requirements ◽  
Three Dimensional Finite Element ◽  
Steel Deck

Different type of deck configuration has been used for suspension bridge depending upon different design requirements. Changes in deck properties lead to changes in behavior of a suspension bridge. In this study, effect of deck modification of a existing bridge from timber to steel deck is considered. Three dimensional finite element models is developed and analyzed changing the deck material from timber to steel which causes reduction in weight and changes in design parameters. This changes the dynamic behavior of the bridge and affects the performance of bearings. The study has been carried out in real world problem encountered in Mugling Suspension Bridge over Trishuli River in Nepal. The study has come up with conclusions and recommendations to increase mass of deck material and replacement of bearings for better performance.Journal of the Institute of Engineering, 2016, 12(1): 39-50

Post-Flutter Bifurcation Behavior in Long-Span Suspension Bridges

2013 ◽  
Author(s):  
Andrea Arena ◽  
Walter Lacarbonara ◽  
Pier Marzocca
Keyword(s):  
Limit Cycle ◽  
Equations Of Motion ◽  
Suspension Bridge ◽  
Sensitivity Analyses ◽  
Design Parameters ◽  
Suspension Bridges ◽  
Limit Cycle Oscillations ◽  
Stability Range ◽  
Long Span ◽  
Fold Bifurcation

A linearized parametric continuum model of a long-span suspension bridge is coupled with a nonlinear quasi-steady aerodynamic model giving the aeroelastic partial differential equations of motion reduced to the state-space ordinary differential form by adopting the Galerkin method. Numerical time-domain simulations are performed to investigate the limit cycle oscillations occurring in the range of post-flutter wind speeds. Continuation tools are thus employed to path follow the limit cycles past the flutter speed where the Hopf bifurcation occurs. The stable post-flutter behavior, which can significantly affect the bridge by fatigue, terminate at a fold bifurcation. This result represents an important assessment of the conducted aeroelastic investigations. The stability range of the limit cycle oscillations is evaluated by carrying out sensitivity analyses with respect to the main design parameters, such as the structural damping and the initial wind angle of attack.

The influence of confocal microscope design on imaging performance

1993 ◽  
Vol 51 ◽  
pp. 144-145
Author(s):  
C J R Sheppard
Keyword(s):  
Image Quality ◽  
Fluorescence Imaging ◽  
Confocal Microscope ◽  
Industrial Applications ◽  
Three Dimensions ◽  
Design Parameters ◽  
Weak Signals ◽  
Size And Shape ◽  
Imaging Performance ◽  
Fundamental Limitation

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.

Sign in / Sign up

Export Citation Format

Share Document