Civil Engineer Expert

Twinkle Kisogawa bridge

An extradosed bridge employs a structure that is frequently described as a cross between a girder bridge and a cable-stayed bridge. The name comes from the French word extradossé, which is derived from the word extrados. Extrados is defined as the exterior curve of an arch.

This description is somewhat deceptive, since many cable-stayed bridges have some sort of box-girder deck. The difference is one of degrees.

A typical cable-stay bridge has a tower with a height above the deck at least half the span to the next support, since the cables are the vertical support and must come at a relatively high angle.

In an extradosed bridge, the deck is directly supported by resting on part of the tower, so that in close proximity to the tower the deck can act as a continuous beam. The cables from a lower tower intersect with the deck only further out, and at a lower angle, so that their tension acts more to compress the bridge deck horizontally than to support it vertically. Thus the cable stays act as prestressing cables for a concrete deck, whether made with I-beam girders or a box girder. The deck of an extradosed bridge can be thinner than that of a comparable span-beam bridge, but must be thicker than that of a conventional cable-stayed bridge of comparable span.
Read the rest of this entry »

Vehicle-Bridge Interaction Dynamics:With Applications To High-Speed Railways

The commercial operation of the bullet train in 1964 in Japan marked the beginning of a new era for high-speed railways. Because of the huge amount of kinetic energy carried at high speeds, a train may interact significantly with the bridge and even resonate with it under certain circumstances. Equally important is the riding comfort of the train cars, which relates closely to the maneuverability of the train during its passage over the bridge at high speeds.

Vehicle-Bridge Interaction Dynamics:

Read the rest of this entry »

Design Guide for Composite Highway Bridges

Composite construction, using a reinforced concrete slab on top of steel girders, is an economical and popular form of construction for highway bridges.

Read the rest of this entry »

AASHTO LRFD Bridge Design Specifications

This major step in improved bridge design and more accurate analysis is expected to lead to bridges exhibiting superior serviceability, enhanced long-term maintainability, and more uniform levels of safety. This edition includes newly updated foundation specifications, as well as updates throughout.

Read the rest of this entry »

Theory and Design of Bridges

Covers current design techniques for both allowable stress and new load and resistance factor design (LRFD) approaches recommended by the forthcoming American Association of State Highway and Transportation Officials draft specifications. Addresses the need for repair or replacement of 225,000 U.S. highway bridges as well as the need for 70,000 new bridges in the next 15 years.
Read the rest of this entry »

This textbook is intended for studies in structural dynamics or wind engineering, with special focus on the stochastic theory of wind induced dynamic response calculations for slender bridges or other line- like civil engineering type of structures. It contains the background assumptions and hypothesis as well as the development of the computational theory that is necessary for the prediction of wind induced fluctuating displacements and cross sectional forces.

Theory of Bridge Aerodynamics

 The book contains detailed and complete examples of relevant cases that are useful for the understanding and the practical application of the theory. The text is at an advanced level in the sense that it requires some knowledge of basic structural dynamics, particularly of solution procedures in a modal format.

Read the rest of this entry »

Examining the fundamental differences between design and analysis, the author explores the close relationship between aesthetic and technical creativity and the importance of the intuitive, more imaginative qualities of design that should be employed by every designer when designing a structure. Aiding designers of concrete bridges in developing an intuitive understanding of structural action, this book thereby encourages innovation and the development of engineering architecture.

The Design of Pre-Stressed Concrete Bridges

Simple, relevant calculation techniques that should precede any detailed analysis are summarized. Construction methods used to build concrete bridge decks and substructures are detailed and direct guidance on the choice and the sizing of different types of concrete bridge deck is given.

Read the rest of this entry »