00820987

Component

https://doi.org/10.3141/1770-24

http://scholar.google.com...rker&publication_year=2001

In recent years, several states including Missouri, Wyoming, California, and Texas experienced fracture failures of traffic signal mast arms. Almost all the failures are associated with the propagation of defects or cracks. It is therefore imperative to evaluate existing mast arms using a simple yet accurate procedure. A statistical methodology is proposed to predict the fatigue life of signal mast arm structures on the basis of field-measured strain data. The annual occurrence of various stress levels is determined using the historical wind speed data in the vicinity of a mast arm structure and the strain readings of the structure under specific wind gusts. For each stress level, the crack initiation and propagation lives are estimated with the strain-life approach and the Paris crack-growth-rate model. They are combined to account for variable stresses by means of Miner's rule and the root-mean-square model, respectively. The stress concentration factor around the arm-post connection is determined using a finite element model. The parameters in the life prediction models are determined with American Society for Testing and Materials flat tension and compact tension tests. The proposed methodology was applied to a 12.8-m (42-ft) long octagonal mast arm and a 16.5-m (54-ft) long circular mast arm in Missouri. It is concluded that signal structures in perfect condition will not crack under natural wind gusts during their service life. However, the 16.5-m-long arm is likely to be vulnerable to tiny defects around the weld connection, but the 12.8-m-long arm is safe unless a visible crack exists.

This paper appears in Transportation Research Record No. 1770, Design of Structures 2001.

English

p. 188-194

2001

Transportation Research Record

0309072328

Figures (9) ; Photos (1) ; References (7) ; Tables (3)

Cracking; Defects; Failure; Fatigue (Mechanics); Fatigue strength; Field tests; Finite element method; Fracture mechanics; Gusts; High mast lighting; Mathematical prediction; Service life; Statistical analysis; Strain (Mechanics); Stresses; Tension tests; Weldments; Wind

Traffic signal mast arms

Bridges and other structures; Data and Information Technology; Design; Highways; I20: Design and Planning of Transport Infrastructure

TRIS, TRB, ATRI

Dec 10 2001 12:00AM

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• DEBRIS FLOW SIMULATION FOR HIGHWAY CROSS CULVERTS
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• DIAGNOSTIC AND IN-SERVICE TESTING OF TRANSIT RAILWAY BRIDGE
• DYNAMIC LOADING OF BRIDGES
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• EFFECTIVE USE OF PUBLIC INVOLVEMENT TO ACHIEVE AESTHETIC QUALITY IN BRIDGE DESIGN
• ESCAPE ADITS FOR TUNNEL SAFETY
• EXPERIMENTAL AND NUMERICAL EVALUATION OF BRACED-CHAIN EYEBAR BRIDGE
• EXPERIMENTAL CHARACTERIZATION OF METALLIC DAMPERS FOR SEISMIC RETROFIT OF HIGHWAY BRIDGES
• FIELD INVESTIGATION OF HIGH-PERFORMANCE CONCRETE BRIDGE DECKS IN SOUTH CAROLINA
• FIELD STUDIES OF STRENGTHENED TIMBER RAILROAD BRIDGE
• HEALTH MONITORING OF IRONTON-RUSSELL BRIDGE FOR RATING PURPOSES
• LONG-TERM DURABILITY OF STRUCTURAL COMPOSITE LUMBER IN BRIDGE APPLICATIONS
• PERFORMANCE IN LIEU OF PRESCRIPTION IN BRIDGE DESIGN: CHANGI AIRPORT MEZZANINE BRIDGE, SINGAPORE
• PERFORMANCE OF FIVE-SPAN STEEL BRIDGE WITH FIBER-REINFORCED POLYMER COMPOSITE DECK PANELS
• PERFORMANCE OF GLASS FIBER-REINFORCED POLYMER DECK ON STEEL GIRDER BRIDGE
• PUBLIC PARTICIPATION AND BRIDGE TYPE SELECTION
• REPAIR AND STRENGTHENING OF CONCRETE STRUCTURES THROUGH APPLICATION OF CORRECTIVE POSTTENSIONING FORCES WITH SHAPE MEMORY ALLOYS
• RETROFITTING TO CORRECT UPLIFT OF CURVED GIRDER BRIDGE THROUGH FIELD TESTING AND ANALYSIS
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• TIME-DEPENDENT DEFLECTION OF THERMOPLASTIC PIPES UNDER DEEP BURIAL
• ULTRASONIC INSPECTION OF GLUED LAMINATED TIMBER FABRICATED WITH DEFECTS
• UPDATE ON ANALYTICAL AND EXPERIMENTAL RESEARCH ON BRIDGE RESTRAINERS
• VIRTUAL REALITY IMAGES TO AID PUBLIC INVOLVEMENT IN APPEARANCE OF ROADS AND BRIDGES