Extending the Service Life of Existing Bridges by Increasing Their Load Carrying Capacity

Extending the Service Life of Existing Bridges by Increasing Their Load Carrying Capacity
Author: Roland H. Berger
Publisher:
Total Pages: 158
Release: 1978
Genre: Bridges
ISBN:

A catalog of bridge deficiencies is developed based on the inspection of over 140 deficient bridges located in Illinois, Florida, Pennsylvania, California, and Tennessee. A classification of structure types is developed for concrete, steel and timber bridges. Deficiencies are related to the structure classification system and a hierarchy of the most common deficiencies established. Techniques presently utilized by state highway departments to correct deficiences are described and evaluated. Several innovative techniques for increasing the load carrying capacity are also described. Utilizing these techniques, increased capacity values are developed. Cost factors are also analyzed and graphic presentations which show the relative merit of each system are presented.

Response Modification for Enhanced Operation and Safety of Bridges

Response Modification for Enhanced Operation and Safety of Bridges
Author: Andrew Gastineau
Publisher:
Total Pages: 44
Release: 2011
Genre: Bridges
ISBN:

This report shows that safe extension of the service life of existing bridge structures is possible through bridge health monitoring and structural response modification. To understand bridge health monitoring and structural response modification and control, it is necessary to examine: 1) common bridge vulnerabilities, 2) bridge loading models, 3) response modification devices, and 4) bridge monitoring systems. The efficacy of response modification techniques on a realistic bridge system were demonstrated using the Cedar Avenue Bridge in Minnesota as a specific example. The Cedar Avenue Bridge is a steel tied arch bridge which means that it is fracture critical. Due to the non-redundant nature of a fracture critical bridge, fatigue failure could be catastrophic and is of concern. Previous research has shown that stress concentrations exist at the joints where the hangers and floor beams are attached to the box girder [7]. Using a simulation of response modification on the Cedar Avenue Bridge model, stress ranges have been reduced on these specific details that are of concern. Modeling using a scissor jack and simple damping device has shown that stress ranges can be reduced by approximately 39% which can lead to life extension of as much as 346%.

Mitigation of Traffic-induced Bridge Vibrations Through Passive and Semi-active Control Devices

Mitigation of Traffic-induced Bridge Vibrations Through Passive and Semi-active Control Devices
Author: Amy R. Magnuson
Publisher:
Total Pages: 56
Release: 2011
Genre:
ISBN:

Many of the U.S. bridges today are reaching or have reached their design life and are beginning to deteriorate and are becoming structurally deficient. Much time, effort, money, and resources go into repairing, rehabilitating, or reconstructing these bridges. Therefore, investigation into valid solutions to extending the safe life of these structures is of utmost importance. A major cause of bridge deterioration is stresses and fatigue induced in the bridge from traffic loading. This paper explores and investigates methods of mitigating traffic-induced bridge vibrations through the integration of control devices to extend the service life of bridges. There are three main classes of structural control devices: passive, semi-active, and active control. Each control scheme has advantages and disadvantages which are discussed in this thesis. To gain a better understanding of both passive and semi-active control strategies, a computer simulation is conducted. The computer simulation allows for a better comparison between passive and semi-active control schemes. The finding from the simulation shows a semi-active control strategy outperforming a passive strategy. The semi-active scheme reduces maximum midspan deflections by 20%, while the passive has a reduction of 12%.

Structural Motion Engineering

Structural Motion Engineering
Author: Jerome Connor
Publisher: Springer
Total Pages: 626
Release: 2014-06-26
Genre: Technology & Engineering
ISBN: 3319062816

This innovative volume provides a systematic treatment of the basic concepts and computational procedures for structural motion design and engineering for civil installations. The authors illustrate the application of motion control to a wide spectrum of buildings through many examples. Topics covered include optimal stiffness distributions for building-type structures, the role of damping in controlling motion, tuned mass dampers, base isolation systems, linear control, and nonlinear control. The book's primary objective the satisfaction of motion-related design requirements such as restrictions on displacement and acceleration and seeks the optimal deployment of material stiffness and motion control devices to achieve these design targets as well as satisfy constraints on strength. The book is ideal for practicing engineers and graduate students.

Concrete

Concrete
Author:
Publisher:
Total Pages: 940
Release: 1974
Genre: Concrete
ISBN: