- Steel bridge design handbook-Limit states
- D. Mertz
- Book Title / Journal: Publication No. FHWA-IF-12-052 - Vol. 10, HDR Engineering, Inc., Pittsburgh, USA
- Year: 2012 , Volume: Vol. 10 , Series:
- Bridge management ; Bridges
- Description
- In the AASHTO LRFD Bridge Design Specifi
cations
, a limit state is defined as “a condition beyond which the bridge or
component ceases to satisfy the provisions for which it was designed.” Bri
dges designed using the limit
-
states philosophy of the
LRFD Specifications must satisfy “specified limit states to achieve the objectives of constructability, safety and serviceabi
lity.”
These objectives are met through the strength, service, fatigue
-
and
-
f
racture and extreme
-
event limit states.
This
module
provide
s
bridge engineers with the background regarding the development and use of the various limit states contained in the LRFD
Specifications.
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- Steel bridge design handbook-Redundancy
- D. Mertz
- Book Title / Journal: Publication No. FHWA-IF-12-052 - Vol. 9, HDR Engineering, Inc., Pittsburgh, USA
- Year: 2012 , Volume: Vol. 9 , Series:
- Bridge management ; Bridges
- Description
- In the context of steel bridge members, nonredundancy or fracture criticality relates to resistance of the entire bridge
superstructure to brittle fracture. The question becomes, can a flaw or crack grow in an
unstable manner as a brittle fracture
resulting in the loss of the member and subsequently the loss of the superstructure?
The issue of redundancy affects the design,
fabrication and in
-
service inspection of steel bridge members when they are classified
as fracture
-
critical members. Of all bridge
construction materials, only steel bridge members are considered as candidates for the fracture
-
critical designation.
This
module
provided engineers with the background concerning redundancy in steel girder brid
ges.
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- Steel bridge design handbook-Loads and load combinations
- D. Mertz
- Book Title / Journal: Publication No. FHWA-IF-12-052 - Vol. 7, HDR Engineering, Inc., Pittsburgh, USA
- Year: 2012 , Volume: Vol. 7 , Series:
- Bridge management ; Bridges
- Description
- Sections 1 and 3 of the
AASHTO LRFD Bridge Design Specifications, 5
th
Edition
discuss various aspects of loads. The load
factors are tabulated in Table 3.4.1
-
1 of the AASH
TO LRFD and are associated with various limit states and further various load
combinations within the limit states. This
module
discusses the various components of load and provides information beyond
that contained in the AASHTO
LRFD
that will be useful t
o the designer. It also discusses and reviews the various limit
-
state
load combinations to assist the designer in avoiding non
-
governing load combinations.
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- Steel Bridge Design Handbook: Design for Fatigue
- D. Mertz
- Book Title / Journal: Steel Bridge Design Handbook
- Year: 2012 , Volume: 12 , Series: FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Steel bridges ; Fatigue
- Description
- Fatigue in metals is the process of initiation and growth of cracks under the action of repetitive tensile loads. If crack growth is allowed to go on long enough, failure of the member can result when the uncracked cross-section is sufficiently reduced such that the member can no longer carry the internal forces for the crack extends in an unstable mode. The fatigue process can take place at stress levels that are substantially less than those associated with failure under static loading conditions. The usual condition that produces fatigue cracking is the application of a large number of load cycles. Consequently, the types of civil engineering applications that are susceptible to fatigue cracking include structures such as bridges. This document provides the practicing engineer with the background required to understand and use the design rules for fatigue resistance that are currently a standard part of design codes for fabricated steel structures.
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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 Fabrication Technologies in Europe and Japan
- K. Verma ; K. Frank ; W. Wright ; R. Medlock ; B. McEleney ; P. Loftus ; B. Kase ; H. Campbell ; A. Wilson ; J. Fisher ; K. Lineham ; M. Cress ; R. Anderson ; A. Shirole ; D. Mertz ; J. Uttrachi ; R. Sathre ; J. Hamilton
- Final Report, No. FHWA-PL-01-018. United States Department of Transportation, Federal Highway Administration. International Technology Exchange Program
- Book Title / Journal:
- Year: 2001 , Volume: , Series:
- Bridge management ; Bridges
PDF |