AN APPROXIMATE SOLUTION OF SUSPENSION BRIDGE UNDER CONSTRUCTION

Abstract In large structures such as towers of suspension bridges or cable-stayed bridges, we often need to suppress the wind-induced vibration for their safety. Especially in the construction stage, the structures are more flexible than the completed ones. This paper discusses the active dampers used to suppress the wind-induced vibration of a tower of a suspension bridge (The Kurushima Bridge 3P Tower) during the construction. The active damper was used to suppress the wind-induced vibration in multiple modes predicted by wind-tunnel test. The controller design of the dampers is based on an H∞ robust control theory. At each erection step, we measured the dynamic properties of the towers to adjust the parameters of the controller using the active dampers as vibration exciters. The measured dynamic properties of the active controlled structures are compared with those of a non-controlled structure. The analysis of free vibration shows the suppression performance of active damper as expected in the controller design.

Download Full-text

Study on Mechanics Performance of Suspension Bridge with 1960 MPa Cable Wire

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.847.135 ◽

2016 ◽

Vol 847 ◽

pp. 135-140

Author(s):

Hao Lei Wang ◽

Chao Zhu

Keyword(s):

Dynamic Properties ◽

High Strength ◽

Suspension Bridge ◽

Natural Vibration Frequency ◽

Dead Weight ◽

Vertical Stiffness ◽

Main Cable ◽

Steel Consumption ◽

Under Construction ◽

Cable Wire

In suspension bridge, the main cable is the major bearing member, instead of the 1770MPa cable wire normally adopted in current design, the application of cable wire strengths up to 1960MPa can lighten the dead weight, reduce the size of tower and anchorage, and shorten the construction period, obtain economical design. In this paper, a under-construction suspension bridge with span of 1688m is taken as a case-study, Comparative analyses are performed mainly focusing on basic parameters, carrying efficiency of main cable, static behavior and dynamic properties as different high strength cable are adopted in this suspension bridge. The results show that compared with 1770MPa main cable, using 1960MPa main cable in suspension bridge is benefit for improving the carrying efficiency of main cable, the steel consumption is also saved by 13%, but the vertical stiffness of the structure is reduced partly; the changes of main cable slightly affect the natural vibration frequency of girder, but have greater influences on vibration of main cable.

Download Full-text

A Magnetic Spectrometer for a Scanning Transmission Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052195 ◽

1974 ◽

Vol 32 ◽

pp. 436-437

Author(s):

A. Kosiara ◽

J. W. Wiggins ◽

M. Beer

Keyword(s):

Scanning Transmission Electron Microscope ◽

Magnetic Spectrometer ◽

Fringe Field ◽

Curvature Radius ◽

Magnetic Pole ◽

Quadrupole Field ◽

Transmission Electron ◽

Scanning Transmission ◽

Under Construction ◽

Image Position

A magnetic spectrometer to be attached to the Johns Hopkins S. T. E. M. is under construction. Its main purpose will be to investigate electron interactions with biological molecules in the energy range of 40 KeV to 100 KeV. The spectrometer is of the type described by Kerwin and by Crewe Its magnetic pole boundary is given by the equationwhere R is the electron curvature radius. In our case, R = 15 cm. The electron beam will be deflected by an angle of 90°. The distance between the electron source and the pole boundary will be 30 cm. A linear fringe field will be generated by a quadrupole field arrangement. This is accomplished by a grounded mirror plate and a 45° taper of the magnetic pole.

Download Full-text

Radiation Damage Studies with the HVEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096655 ◽

1972 ◽

Vol 30 ◽

pp. 680-681

Author(s):

J. J. Laidler ◽

B. Mastel

Keyword(s):

Radiation Damage ◽

Stainless Steels ◽

Volume Expansion ◽

Austenitic Stainless Steels ◽

Test Facility ◽

Fast Breeder Reactors ◽

Breeder Reactors ◽

Under Construction ◽

Development Laboratory ◽

Insight Into

One of the major materials problems encountered in the development of fast breeder reactors for commercial power generation is the phenomenon of swelling in core structural components and fuel cladding. This volume expansion, which is due to the retention of lattice vacancies by agglomeration into large polyhedral clusters (voids), may amount to ten percent or greater at goal fluences in some austenitic stainless steels. From a design standpoint, this is an undesirable situation, and it is necessary to obtain experimental confirmation that such excessive volume expansion will not occur in materials selected for core applications in the Fast Flux Test Facility, the prototypic LMFBR now under construction at the Hanford Engineering Development Laboratory (HEDL). The HEDL JEM-1000 1 MeV electron microscope is being used to provide an insight into trends of radiation damage accumulation in stainless steels, since it is possible to produce atom displacements at an accelerated rate with 1 MeV electrons, while the specimen is under continuous observation.

Download Full-text

Description of a New High Resolution Scanning Transmission EM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095340 ◽

1972 ◽

Vol 30 ◽

pp. 418-419

Author(s):

Michael Beer ◽

J. W. Wiggins ◽

David Woodruff ◽

Jon Zubin

Keyword(s):

High Resolution ◽

Field Emission ◽

Energy Dispersive Spectrometer ◽

Scanning Transmission Electron Microscope ◽

Objective Lens ◽

Condenser Lens ◽

Transmission Electron ◽

Pattern Size ◽

Scanning Transmission ◽

Under Construction

A high resolution scanning transmission electron microscope of the type developed by A. V. Crewe is under construction in this laboratory. The basic design is completed and construction is under way with completion expected by the end of this year.The optical column of the microscope will consist of a field emission electron source, an accelerating lens, condenser lens, objective lens, diffraction lens, an energy dispersive spectrometer, and three electron detectors. For any accelerating voltage the condenser lens function to provide a parallel beam at the entrance of the objective lens. The diffraction lens is weak and its current will be controlled by the objective lens current to give an electron diffraction pattern size which is independent of small changes in the objective lens current made to achieve focus at the specimen. The objective lens demagnifies the image of the field emission source so that its Gaussian size is small compared to the aberration limit.

Download Full-text

Cochlea Under Construction

ASHA Leader ◽

10.1044/leader.ae.16092011.40 ◽

2011 ◽

Vol 16 (9) ◽

pp. 40-41

Author(s):

Jessica J. Messersmith

Keyword(s):

Under Construction

Download Full-text

Participation and learning of the Xakriaba boys, between the hunts, the hoe and the school: Tensions of a debate under construction

PsycEXTRA Dataset ◽

10.1037/e570782013-114 ◽

2013 ◽

Author(s):

Rogerio Correia da Silva

Keyword(s):

Under Construction

Download Full-text

The House That Google Built? Power and Progress under Construction 4.0

Construction Research Congress 2020 ◽

10.1061/9780784482865.062 ◽

2020 ◽

Author(s):

Fred Sherratt ◽

Ruth Dowsett ◽

Simon Sherratt

Keyword(s):

Under Construction

Download Full-text

‘The well-known, old, but still unbeaten track’: Women Poets and Irish Periodical Culture in the Mid-Twentieth Century

Irish University Review ◽

10.3366/iur.2012.0007 ◽

2012 ◽

Vol 42 (1) ◽

pp. 32-52 ◽

Cited By ~ 3

Author(s):

Anne Mulhall

Keyword(s):

Twentieth Century ◽

Literary Culture ◽

Woman Writer ◽

Double Bind ◽

Women Poets ◽

Substantial Body ◽

Growing Body ◽

Critical Attention ◽

Irish Women ◽

Under Construction

While neglected Irish male poets of the mid century have seen some recuperation in recent decades, the work of Irish women poets still languishes in obscurity. A growing body of scholarship has identified the need to bring critical attention to bear on this substantial body of work. In this essay I explore the positioning of Irish women poets in mid-century periodical culture, to flesh out the ways in which the terms of this ‘forgetting’ are already established within the overwhelmingly masculinist homosocial suppositions and idioms that characterized contemporary debates about the proper lineage and aesthetic norms for the national literary culture that was then under construction. Within the terms set by those debates, the woman writer was caught in the double bind that afflicted any woman wishing to engage in a public, politicized forum in post-revolutionary Ireland. While women poets engage in sporadic or oblique terms with such literary and cultural debates, more often their voices are absent from these dominant discourses – the logic of this absence has continued in the occlusion of these women poets from the national poetic canon.

Download Full-text