[雙語(yǔ)翻譯]--外文翻譯-復(fù)合材料公路橋梁疲勞評(píng)估（原文）

1、Journal of Constructional Steel Research 67 (2011) 14–24Contents lists available at ScienceDirectJournal of Constructional Steel Researchjournal homepage: www.elsevier.com/locate/jcsrComposite (steel–concrete) highway br

2、idge fatigue assessmentF.N. Leitão a, J.G.S. da Silva b,?, P.C.G. da S. Vellasco b, S.A.L. de Andrade b, L.R.O. de Lima ba Post-graduate Program in Civil Engineering, PGECIV, State University of Rio de Janeiro, UERJ

3、, Brazilb Structural Engineering Department, State University of Rio de Janeiro, UERJ, Brazila r t i c l e i n f oArticle history: Received 21 June 2010 Accepted 26 July 2010Keywords: Fatigue analysis Structural dynamics

4、 Steel and composite highway bridges Computational modellinga b s t r a c tSteel and composite highway bridges are currently subjected to dynamic actions with variable magnitudes due to the action of vehicles crossing on

5、 the deck pavement. These dynamic actions can generate the nucleation of fractures or even their propagation in the structures. Depending on the magnitude and intensity, these adverse effects can compromise the structura

6、l system response and the reliability which may also lead to a reduction of the expected bridge service life. A composite (steel–concrete) bridge with a 12.50 m roadway width and 0.23 m concrete deck thickness, spanning

7、40.0 m by 13.5 m was investigated in this work. The computational model, developed for the composite bridge dynamic analysis, adopted the usual mesh refinement techniques present in finite element method simulations, and

8、 was implemented in the ANSYS program. The proposed analysis methodology and the procedures presented in the design codes were initially assessed to evaluate the bridge fatigue response in terms of its structural service

9、 life. The stress cycle counting techniques and the cumulative damage rule application had been analyzed through S–N curves, based on an extensive revision of steel and composite bridges’ service life and theoretical fat

10、igue aspects in steel structures. The investigation also considered the recommended procedures used for the steel and composite structures’ main codes. The main conclusions of this paper focused on alerting structural en

11、gineers to the possible distortions, associated with the steel and composite bridges’ service life when subjected to vehicles’ dynamic actions. © 2010 Elsevier Ltd. All rights reserved.1. IntroductionSteel and compo

12、site highway bridges are usually subjectedto dynamic actions of variable magnitudes due to the actions of vehicles crossing on the deck pavement. These dynamic actions can generate the nucleation of fractures or even the

13、ir propagation on the structure. Depending on the magnitude and intensity, these adverse effects may compromise the structural system response reliability that could also lead to a reduction of the expected bridge servic

14、e life.Proper consideration of all of the aspects mentioned earlierencouraged our team to develop an analysis methodology with emphasis to evaluate the stresses through a dynamic analysis of highway bridge decks, includi

15、ng the action of vehicles crossing on the pavement surface, [1–8].The present investigation utilises techniques for counting stresscycles and for applying cumulative damage rules combined with S–N curves. The first steps

16、 of the composite highway bridge study involved an extensive literature review of the techniques used to define steel and composite bridges’ service life, a study of? Corresponding author. Tel.: +55 21 2587 7537; fax: +5

17、5 21 2587 7537.E-mail addresses: jgss@uerj.br, jgss@eng.uerj.br (J.G.S. da Silva).the theoretical aspects of fatigue in steel, and the recommended procedures present in the main steel and composite structural design code

18、s [9–11].The design codes recommend the adoption of the S–N curvesassociated with the Miner damage rule to evaluate the steel and composite bridges’ fatigue and service life. These codes also recommend that the bridge st

19、ructure designs should avoid local stress concentrations, to prevent possible fatigue points.The investigated composite bridge has a roadway width of12.50 m and a concrete deck thickness of 0.23 m, spanning 40.0 m by 13.

20、5 m. The structural system consists of four longitudinal composite girders and a concrete deck. The computational model used in the composite bridge dynamic analysis, adopts the usual mesh refinement techniques present i

21、n finite element method simulations implemented in the ANSYS program [12].The beam steel sections were simulated by three-dimensionalbeam and shell finite elements. The beam web was represented by shell finite elements.

22、The top and bottom beam flanges and the longitudinal and vertical stiffeners were simulated by three- dimensional beam elements by considering flexural and torsional effects. The bridge concrete slab was simulated by she

23、ll finite elements.The proposed analysis methodology and the procedurespresented in the design codes [9–11] were used to evaluate the bridge fatigue response in terms of its structural service life.0143-974X/$ – see fron

24、t matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.jcsr.2010.07.01316 F.N. Leitão et al. / Journal of Constructional Steel Research 67 (2011) 14–240.88L 137 × 127 × 10L 137 × 127 &#

25、215; 10L 137 × 127 × 102L 127 × 127 × 10 2L 127 × 127 × 10 2L 127 × 127 × 100.23 2.001.25 3.50 3.50 3.50 1.25Fig. 1. Bridge cross section.Fig. 2. Bridge top view.Fig. 3. Three-dime

26、nsional bridge view.Fig. 4. Different cross sections used along the bridge length.and one rotational) and two axes to simulate each single vehicleas illustrated in Fig. 5. Translational vertical displacements androtation

27、al displacements are considered in the vehicle model.Fig. 5 demonstrates this representation and uses the followingnotation: d is the distance between axles; uv is the vehicle’s verticaldisplacement of the suspended mass

28、; θs is the vehicle’s rotationaldisplacement related to the suspended mass; u1 and u2 are thevehicle’s vertical displacements of the non-suspended mass; ms is the vehicle’s suspended mass; mnsi is the vehicle’s ith non-s

29、uspended mass (for each axle), respectively; kvsi and kvpi are theith stiffness coefficients related to vehicle suspension and tires(for each axle), respectively; cvsi and cvpi are the ith dampingcoefficients related to

30、vehicle suspension and tires (for each axle), respectively.The vehicle’s natural frequencies oscillating on rigid bases(vertical motion), corresponding to the vehicle suspended mass (suspension system) and non-suspended

31、mass degrees of freedom (tires); see Fig. 5, were made equal to 3.0 Hz and 20.0 Hz, respectively [15–17]. However, the vehicle model has a lower natural frequency, associated with the vehicle suspended mass (suspension s

32、ystem) degree of freedom which is equal to a 2.3 Hz (rotational motion) [15–17].The relative damping coefficient of the vehicle’s vibration modewith predominant movement of the vehicle’s suspended mass is assumed to be ξ