Span Arch Bridge Research Articles

Bridge Structural Optimization Through Step-by-Step Evolutionary Process

In this paper, the structural optimization process aiming to reduce the weight of the superstructure of a five span arch bridge, built in the Province of Venice, Italy, and spanning the Piave River in the town of San Donà, is presented. The original project, with a pre-stressed concrete superstructure, was re-considered during construction because of the following two unexpected events. First, the approved new seismic national regulation became effective when the bridge was already partially built. As a result, existing foundations became unable to withstand the prescribed new seismic action. Furthermore, the Venice Water Authority, responsible for the management of the river spanned by the bridge, declared that erection phases without any provisional supports and scaffolding resting on the riverbed, as foreseen by the original project, should be preferred. Between the two possible identified design strategies able to deal with the mentioned problems, namely, the strengthening of the foundations or the lightening of the superstructure, the second option was chosen, on the basis of engineering judgement concerning the simplification of construction procedures, timing and budget. The search for the lightest possible solution, with the restraint given by the approved aesthetics of the original design and the need of keeping within the former budget, brought to the conclusion that an evolutionary structural optimization (ESO) process could be suitably applied to a composite steel and concrete superstructure.

Dynamic monitoring of a long span arch bridge

A new multi-channel dynamic monitoring system was recently installed in a long span concrete arch bridge that crosses the Douro River in the city of Porto, Portugal: the “Infante D. Henrique” bridge. This paper describes the experimental and numerical studies developed shortly after construction of the bridge, characterizes the installed monitoring system and presents the results achieved with the software developed to process the data that is continuously received through the Internet. Preliminary studies included the development of an ambient vibration test and the construction of a numerical model of the bridge that was “tuned” to fit the bridge dynamic properties identified by the ambient vibration test. The routines implemented include the on-line automatic identification of the bridge’s natural frequencies with the Frequency Domain Decomposition method, enabling the tracking of the bridge’s first 12 natural frequencies. This unique feature is only possible due to the combination of high-quality acquisition equipment with state of the art processing algorithms.

A comparative study between China and U.S. on seismic design philosophy and practice of a long span arch bridge

This paper presents the first of a series of case studies on the seismic design of long span bridges (cable-stayed bridges, suspension bridges and arch bridges) under a cooperative research project on seismic behavior and design of highway bridges between the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University and the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo. The objective of this series of case studies is to examine the differences and similarities on the seismic design practice of long span bridges in China and the U.S., to identify research needs and to develop design guidelines beneficial to bridge engineers in both countries. Unlike short to medium span bridges, long span bridges are not included in most seismic design specifications, mainly because they are location dependent and structurally unique. In this paper, an available model of a steel tied half through arch bridge with a main span of 550m in China is discussed. Analysis is focused on comparisons of the seismic responses due to different ground motions. Seismic design criteria and seismic performance requirements for long span bridges in both countries were first introduced and compared, and then three near field earthquake records with large vertical components were selected as the excitations to examine the seismic behavior and seismic vulnerability of the bridge. Results show that (1) the selected near field ground motions cause larger responses to key components (critical sections) of the bridge (such as arch rib ends) with a maximum increase of more than twice those caused by the site specific ground motions; (2) piers, longitudinal girders and arch crowns are more vulnerable to vertical motions, especially their axial forces; and (3) large vertical components of near field ground motions may not significantly affect the bridge’s internal forces provided that their peak acceleration spectra ordinates only appear at periods of less than 0.2s. However, they may have more influence on the longitudinal displacements of sliding bearings due to their large displacement spectra ordinates at the fundamental period of the bridge.

Performance of a stress-laminated-timber arch bridge

For the past three years the authors have been involved in the optimisation of the performance of stress-laminated-timber arch (SLTA) structures by utilising the strength properties of timber in an arching action for use as vehicle and pedestrian bridges. During this time over 20 permanent bridges have been built and eight have been load tested. The overall aim of this extensive research programme has been to develop structural uses for low-grade, UK-grown, timber and it has been shown that arches, using timber in compression, are an extremely effective technique for bridges. Timber structures have a very high sustainability value while being low cost and employing less early capital. These bridges on public roads can help increase public confidence in timber as a viable structural material. As part of a series of field and laboratory tests on SLTA bridges, a 20 m span arch bridge was designed and constructed at the Glentress Forestry Commission site near Peebles, in August 2004. The bridge has since been subjected to a series of extensive static and dynamic loads evaluating its response to crowd and vandal loadings. The results have confirmed predictions that the strength and stiffness of this type of construction was well beyond the strength normally expected from a slender timber structure. This paper details the construction and compares the analysis, design and load testing of the latest 20 m span full-scale SLTA test bridge at Glentress. The extensive testing programme, augmented by analytical work, aims to develop reliable design guidelines for arch structures using UK softwood.

Dr. MIKISHI ABE and Early Days of Elevated Railway Viaducts in Japan

Introduction of reinforced concrete was a very important turning point in the history of elevated railway viaducts in Japan. Dr. Mikishi Abe (1883-1965) was one of the key persons to spread this technology. He entered Government Railways after graduating from the Department of Civil Engineering, Sapporo Agricultural College, in 1905, and went to lllinois University to study the newest technology about reinforced concrete. He returned to Government Railways from the U. S. in 1914, and designed the widest span arch bridge made by reinforced concrete in Japan. But his name was well known only in the architectural field before he became independent as an architect in 1920. Therefore, this report describes his achievement in the civil engineering field and his role as a civil engineer. From the results of this study, it is clear that he made an important contribution to the development of elevated railway viaducts.

Engineering geology of Snebra Ghyll bridge, A595(T) Hensingham Bypass

Abstract The construction of Hensingham Bypass, Cumbria was completed in December 1991. Snebra Ghyll is a deep ravine opening into convex, rounded slopes at the top. An eight span arch bridge was adopted for the ghyll crossing, with bank seats supported on the approach embankments. The northern approach embankment has reinforced earth slopes above the ravine. Intermediate piers and arch springings are founded on bedrock, in which open joints were identified. These were grouted before foundation construction. Steep faces beneath the bridge are protected by soil nailing.

Stone Arch Bridges Under In-plane Loading:Discrete Element Modelling And IncrementalAnalysis Up To Failure

Computer modelling by the Discrete Element Method and incremental analysis up to failure have been worked out for a one span arch bridge made by sandstone blocks acted by monotonically increasing in-plane loading. The numerical simulation has been carried out via ANSYS code. Micromodelling has been adopted; the single stone voussoir has been discretized by means of a four-node plane element, whereas continuous joints between voussoirs has been represented by discrete contact elements. Material of stone voussoirs has been assumed to be indefinitely linear elastic; contact elements exhibit in tangential direction a refined frictional behaviour where friction increases as normal compression does and carry no tension in normal direction. Dead loads are given by own weight of the arch and of the filling, and by the lateral fill pressure. Live load is represented by a point force separately applied at three different locations: a) mid span, b) one-third, and c) two-thirds of the half-span far from the mid span. A geometrically non linear incremental analysis has been performed up to failure under in-plane monotonically increasing load in order to trace normal force versus closure and shear force versus slip diagrams at contact elements involved in joint opening, and to evaluate the ultimate load at failure, without the drawback via priori defining a collapse mechanism. Transactions on the Built Environment vol 39 © 1999 WIT Press, www.witpress.com, ISSN 1743-3509

Seismic Strengthening Of Historic ConcreteArch Bridges

The most common historic bridge type in California is the concrete bridge. These concrete bridges have a distinct local imprint, the technology is innovative and the designers have placed great emphasis on the aesthetics. The most graceful are the concrete arch bridges, often located in the rugged wilderness of the State.' Many of these historic concrete bridges show sign of deterioration due to corrosion or excessive cracking. They do not meet the current requirement for traffic loading and they no longer have an acceptable safety margin against seismic failure. The present technology for the preservation and seismic strengthening of historic concrete arch bridges in California is demonstrated in case studies. These include the Donner Summit Bridge, a fixed type open spandrel arch bridge in the Sierra Nevada, the Colorado Street Bridge, an eleven span arch bridge in Pasadena, and the Diestelhorst Bridge, a five span concrete arch bridge across the Sacramento River in Northern California.

Closure to “Hydraulics of Single Span Arch Bridge Construction”

Closure to “Hydraulics of Single Span Arch Bridge Construction”

Discussion of “Hydraulics of Single Span Arch Bridge Construction”

Discussion of “Hydraulics of Single Span Arch Bridge Construction”

Hydraulics of Single Span Arch Bridge Construction

Series of model tests were run for condition of no skew, no eccentricity, and no entrance rounding; generalized backwater equation is presented, by means of which backwater superelevation may be evaluated in terms of bridge span, stream width and Froude number of approaching flow.