- Steel Bridge Design Handbook: Splice Design
- M. Bunner
- Book Title / Journal:
- Year: 2012 , Volume: 14 , Series: o. FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Bolted Field Splices ; Steel Girders
- Description
- This module focuses on the factors which influence and the principles of the design of bolted field splices. Factors that influence field splice design and layout are presented, including span layout, curvature, and girder properties. General design provisions are also addressed in this module, including flexural resistance provided by a bolted field splice at the Strength and Service limit states, as well as detailing considerations. Lastly, a thorough design example of a bolted field splice for a steel I-girder is provided, illustrating calculations for flange and web stress, splice plate design, and bolt design. Strength, Service, and Fatigue limit states are considered, and design checks are provide for tension, compression, and shear resistance of splice plates, fracture and bearing resistance of splice plates, and strength and slip resistances of the bolted connections.
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- Steel Bridge Design Handbook: Bearing Design
- M. Kaczinski
- Book Title / Journal: Steel Bridge Design Handbook
- Year: 2012 , Volume: , Series:
- Bridge management ; Bridges
- Keywords: bearing design ; steel bidges
- Description
- Steel bridge bearings may be divided into three general types: elastomeric bearings, high-load multi-rotational bearings, and mechanical bearings. The designer must determine which bearing type is best suited to cost effectively accommodate the design
requirements. This module provides practical information for efficient bearing design and detailing. The information contained in this module is drawn largely from the following two sources - NSBA’s “Steel Bridge Bearing and Selection and Design
Guide,” Highway Structures Design Guide, Volume II, Chapter 4 (HSDH Volume II, Chapter 4)) and AASHTO/NSBA Steel Bridge Collaboration, G9.1-2004 “Steel Bridge Bearing Design and Detailing Guidelines.”
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- Steel Bridge Design Handbook: Substructure Design
- D. Coletti ; J. Sheahan
- Book Title / Journal: FHWA-IF-12-052
- Year: 2012 , Volume: 16 , Series:
- Bridge management ; Bridges
- Keywords: Substructure ; pile foundations ; Drilled Shaft Foundations
- Description
- While the main focus of the Steel Bridge Design Handbook is the design of steel girder superstructures, the overall design process associated with the design of substructures is equally important. This module provides an overview of many issues associated with substructure and foundation design.
Many factors influence the selection of substructure and foundation materials, types, configurations, positions, and orientations. Often, existing constraints will limit the range of options and intrinsically lead the designer to only one or a few feasible solutions. This module provides designers with an overview of several foundation types including shallow foundations such as spread footings, and deep foundations that utilize piles or drilled shafts. The module also discusses conventional, integral, and semi-integral abutments, and provides considerations for the design and detailing of these substructure components. Several
considerations for pier selection are also presented, including multi-column piers, single column piers, pile bents, straddle bents, and integral pier caps. Lastly, this module provides designers with information regarding substructure software availability,
seismic design, precast substructures, and superstructure and substructure interaction.
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- Steel Bridge Design Handbook: Bridge Deck Design
- B. Chavel
- Book Title / Journal: Steel Bridge Design Handbook
- Year: 2012 , Volume: 17 , Series: FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Steel Bridge ; Deck Design ; Concrete Deck ; Precast Concrete Deck
- Description
- The primary function of a bridge deck is to support the vehicular vertical loads and distribute these loads to the steel superstructure. This module provides practical information regarding the decking options and design considerations for steel bridges, presenting deck types such as concrete deck slabs, metal grid decks, orthotropic steel decks, wood decks, and several others. The choice of the particular deck type to use can depend on several factors, which may include the specific application, initial cost, life cycle cost, durability, weight, or owner requirements. For the deck types discussed herein, a brief description of the particular deck type is given, in addition to general design and detail considerations.
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- Steel Bridge Design Handbook: Load Rating of Steel Bridges
- D. Mertz
- Book Title / Journal: Steel Bridge Design Handbook
- Year: 2012 , Volume: 18 , Series: FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Steel Bridge ; Load Rating ; LRFR ; Live-load Capacity
- Description
- Load rating is defined as the determination of the live load carrying capacity of a bridge using as-built bridge plans and supplemented by information gathered from the latest field inspection. Load ratings are expressed as a rating factor or as a tonnage for a particular vehicle. Emphasis in load rating is on the live-load capacity and dictates the approach of determining rating factors instead of the design approach of satisfying limit states. Existing highway bridges are rated to prioritize a bridge owner’s needs, assure the traveling public’s safety, and facilitate the passage of goods. Bridges that cannot safely carry statutory loads, based on a load-rating evaluation, should be load posted, rehabilitated or replaced. This module informs designers of load ratings, and discusses the LRFR methodology used for load rating evaluation.
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- Steel Bridge Design Handbook Design Example 1: Three-Span Continuous Straight Composite Steel I-Girder Bridge
- M.A. Grubb ; R.E. Schmidt
- Book Title / Journal:
- Year: 2012 , Volume: 20 , Series: FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Steel bridges ; AASHTO LRFD ; shear connector
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- Steel Bridge Design Handbook Design Example 2A: Two-Span Continuous Straight Composite Steel I-Girder Bridge
- K. Barth
- Book Title / Journal:
- Year: 2012 , Volume: 21 , Series: FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Steel Bridge ; Steel I-Girder ; Moment Redistribution ; Cross Frame Design
- Description
- The purpose of this example is to illustrate the use of the AASHTO LRFD Bridge Design for the design of a continuous two span steel I-girder bridge. The design process and corresponding calculations for steel I-girders are the focus of this example, with particular emphasis placed on illustration of the optional moment redistribution procedures. All aspects of the girder design are presented, including evaluation of the following: cross-section proportion limits, constructibility, serviceability, fatigue, and strength requirements. Additionally, the weld design for the web-to-flange joint of the plate girders is demonstrated along with all applicable components of the stiffener design and cross frame member design.
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- Steel Bridge Design Handbook Design Example 2B: Two-Span Continuous Straight Composite Steel Wide-Flange Beam Bridge
- K. Barth
- Book Title / Journal:
- Year: 2012 , Volume: 22 , Series: No. FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Steel Bridge ; Steel wide-flange beam ; Moment Redistribution ; AASHTO LRFD ; Wind on Structure
- Description
- This design example presents an alternative design for that presented in the Steel Bridge Design Handbook Design Example 2A. Specifically, the design of a continuous steel wide-flange beam bridge is presented using a standard shape rolled I-beam, as an alternative to the plate girder design. The AASHTO LRFD Bridge Design Specifications are the governing specifications and all aspects of the provisions applicable to wide-flange beam bridge design (cross-section proportion limits, constructibility, serviceability, fatigue, and strength requirements) are considered. Furthermore, the optional moment redistribution specifications will be invoked. In addition to the beam design, the design of the concrete deck is also included. A basic wind analysis of the structure is also presented.
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- Steel Bridge Design Handbook Design Example 3: Three-Span Continuous Horizontally Curved Composite Steel I-Girder Bridge
- J. Rivera ; B. Chavel
- Book Title / Journal:
- Year: 2012 , Volume: 23 , Series: No. FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Curved I-Girder Bridge ; Bridge design ; LRFD ; Bolted Field Splice ; Cross Frame
- Description
- Horizontally curved steel bridges present many unique challenges. Despite their challenges, curved girder bridges have become widespread and are commonly used at locations that require complex geometries and have limited right-of-way, such as urban interchanges. Some of the important issues that differentiate curved steel girders from their straight counterparts include the effects of torsion, flange lateral bending, their inherent lack of stability, and special constructibility concerns. Also, the complex behavior of horizontally curved bridges necessitates the consideration of system behavior in the analysis.
This design example illustrates the design calculations for a curved steel I-girder bridge, considering the Strength, Service, fatigue and Constructibility Limits States in accordance with the AASHTO LRFD Bridge Designs specifications. Calculations are provided for design checks at particular girder locations, a bolted field splice design, a cross frame member design, shear connector design, and a bearing stiffener design.
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- Steel Bridge Design Handbook Design Example 4: Three-Span Continuous Straight Composite Steel Tub Girder Bridge
- B. Chavel ; J. Carnahan
- Book Title / Journal:
- Year: 2012 , Volume: 24 , Series: FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Steel Tub Girder ; Steel Box Girder ; Lateral Bracing ; Design Example ; Steel Bridge
- Description
- Tub girders are often selected over I-girders because of their pleasing appearance offering a smooth, uninterrupted, cross section. Bracing, web stiffeners, utilities, and other structural and nonstructural components are typically hidden from view within the steel tub girder, resulting in the tub girders clean appearance. Additionally, steel tub girder bridges offer advantages over other superstructure types in terms of span range, stiffness, durability, and future maintenance.
This design example demonstrates the design of a tangent three-span continuous composite tub girder bridge with a span arrangement of 187.5 ft - 275.0 ft - 187.5 ft. This example illustrates the flexural design of a section in positive flexure, the flexural design of a section in negative flexure, the shear design of the web, the evaluation of using a stiffened versus an unstiffened bottom flange in the negative flexure region, as well as discussions related to top flange lateral bracing and bearing design.
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- Steel Bridge Design Handbook Design Example 5: Three-Span Continuous Horizontally Curved Composite Steel Tub-Girder Bridge
- B. Chavel ; J. Rivera
- Book Title / Journal:
- Year: 2012 , Volume: 24 , Series: FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Steel Tub Girder Bridge ; Steel Box Girder Bridge ; LRFD ; Bolted Field Splice ; Box Girder Distortional Stresses
- Description
- Tub girders, as closed-section structures, provide a more efficient cross section for resisting torsion than I-girders, which is especially important in horizontally curved highway bridges. The increased torsional resistance of a closed composite steel tub girder also results in an improved lateral distribution of live loads. For curved bridges, warping, or flange lateral bending, stresses are lower in tub girders, when compared to I-girders, since tub girder carry torsion primarily by means of St. Venant torsional shear flow around the perimeter of their closed sections, whereas I-girders have very low St. Venant torsional stiffness and carry torsion primarily by means of warping.
This design example illustrates the design calculations for a curved steel tub girder bridge, considering the Strength, Service, fatigue and Constructibility Limits States in accordance with the AASHTO LRFD Bridge Designs specifications. Calculations are provided for design checks at particular girder locations, a bolted field splice design, an internal pier diaphragm design, and a top flange lateral bracing member design.
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- Steel Bridge Design Handbook: Corrosion Protection of Steel Bridges
- R. Kogler
- Book Title / Journal: FHWA-IF-12-052
- Year: 2012 , Volume: 19 , Series:
- Bridge management ; Bridges
- Keywords: Steel Bridge ; Corrosion ; Steel Coatings
- Description
- Corrosion is a serious threat to the long-term function and integrity of a steel bridge. Structural steel will corrode if left unprotected or inadequately protected from the natural environment. This corrosion can take the form of general uniform thickness loss or concentrated pitting depending on exposure to the environment and the steel design detail in question. Bridge designers should view corrosion as a long term threat to the integrity of the bridge structure, and is a critical consideration that must be addressed in a rational manner during the design process.
While there are several proven strategies for corrosion protection of steel bridges, there is no universal solution. The proper
system must be chosen to accommodate cost, fabrication and productivity, and long term performance and maintenance. Additionally, each corrosion protection system must be selected based on the anticipated exposure of the structure to corrosive elements over its lifetime. This module highlights the most common issues confronting bridge designers regarding corrosion protection and provides guidance in this area.
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- Comparison of the Seismic Performance of Equivalent Straight and Curved Bridges due to Transverse Seismic Excitation
- E. Khan ; M.J. Kowalsky ; J.M. Nau
- Book Title / Journal: 15th World Conference on Earthquake Engineering
- Year: 2012 , Volume: , Series:
- Bridge management ; Bridges ; Earthquake engineering
- Keywords: Direct Displacement Based Design ; Bridges ; Transverse Seismic Design of Curved Bridge
- Description
- This study compares the transverse response of equivalent straight and curved bridges to investigate the hypothesis made by the AASHTO Guide Specification for LRFD Seismic Bridge Design that curved bridges may be analyzed as if they are straight, provided the bridge is regular. For this purpose curved bridges with subtended angles of 15, 30, 45, 60, 75, and 90 degrees, having the total arc length equal to the length of the equivalent straight bridge, are considered. Other parameters considered in this study are the number of spans
(two, four and six), and abutment restraints (9 different conditions). The equivalent straight bridges are designed using the Direct Displacement Based Design (DDBD) procedure including these parameters. The resulting designs are then analyzed with Inelastic Time History Analysis using both straight and curved geometry. Each bridge was subjected to 7 spectrum compatible time histories. Individual as well as average results are tabulated.
It is observed that deviation in the response of the curved bridge from the equivalent straight bridge increases as the subtended angles become larger and the number of spans reduces. It was also found that the type and degree of abutment restraint is a rather critical parameter in controlling the response of the bridge, the most significant being longitudinal abutment restraint which had a profound impact on results.
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- Study of early-age bridge deck cracking in Nevada and Wyoming.
- P.E. Stutzman ; A. Sakulich ; D.P. Bentz ; W.J. Weiss
- NISTIR 7841, National Institute of Standards and Technology, U.S. Department of Commerce
- Book Title / Journal:
- Year: 2012 , Volume: , Series:
- Bridge management ; Bridges
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- Bridge piers having structural fuses and bi-steel columns I: experimental testing.
- S. El-Bahey ; M. Bruneau
- ASCE Journal of Bridge Engineering, 17 (1), pages 25-35.
- Book Title / Journal:
- Year: 2012 , Volume: , Series:
- Bridge management ; Bridges
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