Influence of Secondary Components on the Serviceability of Steel Girder Highway Bridges PDF Download

Author: Mohamed Abdel-Azim Elewa
Publisher:
ISBN:
Category : Girders
Languages : en
Pages : 404

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Author: Michael Jay Lewis
Publisher:
ISBN:
Category : Civil engineering
Languages : en
Pages :

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ABSTRACT: When considering the design of bridge girders, the American Association of State Highway and Transportation Officials (AASHTO) determine how the loads will be transferred to each girder. The equations used in AASHTO Load and Resistance Factor Design (LRFD) neglect the inertia added from secondary elements such as barriers and curbs. By neglecting these added effects, many bridges that are already built could have more strength than initially designed for. If the effects of these secondary elements were considered, it would be possible to reduce the distribution factors that are given for interior and exterior girders. The bridge of concern for this project has four spans and was built in the early 1950s. Some repair work and modifications were conducted on the bridge and a load test was performed a week afterwards. The tests were done to find out if the repairs were adequate based on full composite action between the girders and the slab. During this initial test, some problems were discovered in one of the interior spans. This interior span is unique because it contains an expansion joint and a physical barrier and curb joint at the mid-span of the bridge. After problems were discovered, the physical joints were recommended to be grouted and a second load test was conducted afterwards. The second load test yielded much lower strains in the exterior girders due to the decrease in localized stress at the physical joint. In order to prove that filling the joint could improve the bridges strength, a finite element model was constructed to simulate this activity. Two models were made, one prior to filling the physical barrier and curb joints and one after. The test data was compared to the data from the finite element model to ensure accuracy. After the model was calibrated, the secondary members of the bridge were modified to study their effects. The primary goal of this research is to prove that a physical joint in a continuous exterior secondary element will cause the same amount of strain at its location as if they weren't there to begin with. By analyzing the finite element model data, it was found that when the joint is filled the behavior of the bridge changes and the exterior girder has up to 50% reduction in strain. The effect of concrete cracking and stress distribution that is associated with it is a secondary topic that was discussed because it was a driving factor in the model calibration.

Author: J. M. Kulicki
Publisher: Transportation Research Board
ISBN: 0309098556
Category : Bridges
Languages : en
Pages : 81

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This report contains the findings of research performed to develop design specifications for horizontally curved steel girder bridges.

Author: Theodore V. Galambos
Publisher: Transportation Research Board
ISBN: 9780309053501
Category : Technology & Engineering
Languages : en
Pages : 124

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Author: Chan-Hee Park
Publisher:
ISBN:
Category :
Languages : en
Pages : 412

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Author: Marwan Mohammad Salim Kobrosly
Publisher:
ISBN:
Category :
Languages : en
Pages : 146

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The analysis of bridge superstructures is complicated by the geometric boundaries and loading conditions. AASHTO Bridge Specifications contain a simple procedure used in the analysis and design of steel girder bridges. This procedure is to isolate individual girders subjected to a single line of w heel loads from a design truck and then calculate the maximum bending moments. The wheel loads are positioned on the girder to produce maximum bending moment which is then multiplied by an empirical distribution factor. Recently, these factors have been updated based on finite-clement analysis and parametric studies to include major bridge parameters such as: girder spacing, span length, and cross-sectional properties. The findings of previous research reported by the authors about the performance of common finite-element modeling techniques will be employed to investigate other bridge parameters thought to influence the wheel load distribution. Previous research reported in the literature did not investigate the effect of sidewalks and railings on the wheel load distribution in steel girder bridges, the current research will employ recommended dimensions for sidewalks and railings by the AASHTO Bridge Specifications to study their influence on the wheel load distribution. A typical one-span, two-lane, composite steel girder highway bridge was selected to perform the parametric study. The bridge superstructure will be idealized using: (a) quadrilateral plate bending and stretching (shell) elements for the concrete slab, sidewalk, and railing, and space frame elements for steel girders with the centroid of girders coinciding with the one of the concrete slab; (b) eight-node brick elements for the concrete slab, sidewalk, and railing, and quadrilateral shell elements for the flanges and web of the steel girders, This research wilt report the wheel load distribution results of bridges with various combinations of span lengths and girder spacings along with the presence of sidewalks and/or railings on one or both sides of the bridge cross-section The results will serve to assess the current AASHTO practice which is conservative by ignoring the presence of sidewalks and railing when evaluating or designing highway bridges.

Author: J. F. Mirza
Publisher:
ISBN:
Category : Prestressed concrete
Languages : en
Pages : 123

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Author: James R. Staebler
Publisher:
ISBN: 9781124260785
Category : Bridges
Languages : en
Pages : 93

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Current AASHTO LRFD Bridge Design Specifications Service I deflection limits are in place with the purpose to prevent deformation-induced structural damage and psychological user-discomfort from excess bridge vibration. Previous research has shown that deflection criterion alone is insufficient in controlling excess bridge vibrations and structural deterioration of the concrete deck. Previous research shows that natural frequency criteria better controls excess vibration than deflection criteria. In addition, previous research shows no significant correlation between deflection and structural deformation of the concrete deck slab. In order to better control excess bridge vibrations and deformation-induced structural deterioration, two new separate criteria formulations are proposed. The first formulation consists of a natural frequency criteria transformed into deflection type terms familiar to the typical bridge engineer. The second proposed formulation directly controls the acting flexural strain in the concrete deck to control deformation-induced structural damage. The proposed serviceability criteria are applied to a database of 195 steel girder bridges. Both the as-built behavior and the design optimized behavior are examined and compared to current AASHTO serviceability criteria.

Author: Firas Nazih Bou Diab
Publisher:
ISBN:
Category :
Languages : en
Pages : 200

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The current thesis presents the finite element results of a parametric study to accurately evaluate the effect of skewness on wheel load distribution in steel g irder highway bridges. The finite element method is used to investigate the effect of span length, girder spacing, and skewness, on one-span simply supported, two-lane, th reelane, and four-lane steel girder bridges. Five span lengths and three girder spacings are examined in combination with six skew angles, for a total of 270 bridges analyze d and reported in the study. Various positions of the design trucks are assumed, longi tudinally and transversally, in order to produce maximum bending moments. The finite eleme nt modeling consists of shells and frames, for concrete slab and steel girders, res pectively, and composite action between slab and girders is assumed. The finite element pro gram SAP2000 is used in the analysis, and the longitudinal bending moments are comput ed and corresponding wheel load distribution factors on the girders are reported an d discussed for various skew angles. The finite element analysis results for skewe d bridges are compared to the reference straight bridges as well as to the America n Association for State Highway and Transportation Officials (AASHTO) Standard Specifications and LRFD procedures. This study will assist bridge engineers in performing realistic analysis and design of simply supported, multi-lane, skewed steel girder bridges as well as evaluate the load carrying capacity of existing struct ures.

Author: James L. Martin
Publisher: CRC Press
ISBN: 1138000868
Category : Science
Languages : en
Pages : 5742

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Focusing on fundamental principles, Hydro-Environmental Analysis: Freshwater Environments presents in-depth information about freshwater environments and how they are influenced by regulation. It provides a holistic approach, exploring the factors that impact water quality and quantity, and the regulations, policy and management methods that are necessary to maintain this vital resource. It offers a historical viewpoint as well as an overview and foundation of the physical, chemical, and biological characteristics affecting the management of freshwater environments. The book concentrates on broad and general concepts, providing an interdisciplinary foundation. The author covers the methods of measurement and classification; chemical, physical, and biological characteristics; indicators of ecological health; and management and restoration. He also considers common indicators of environmental health; characteristics and operations of regulatory control structures; applicable laws and regulations; and restoration methods. The text delves into rivers and streams in the first half and lakes and reservoirs in the second half. Each section centers on the characteristics of those systems and methods of classification, and then moves on to discuss the physical, chemical, and biological characteristics of each. In the section on lakes and reservoirs, it examines the characteristics and operations of regulatory structures, and presents the methods commonly used to assess the environmental health or integrity of these water bodies. It also introduces considerations for restoration, and presents two unique aquatic environments: wetlands and reservoir tailwaters. Written from an engineering perspective, the book is an ideal introduction to the aquatic and limnological sciences for students of environmental science, as well as students of environmental engineering. It also serves as a reference for engineers and scientists involved in the management, regulation, or restoration of freshwater environments.