- 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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- 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 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 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: 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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