Am PhD student in structural engineering, my study recommendations impose me to publish one article in ASCI journal with high rank "structure engineering journal”. So I want article with perfect work including results come from experimental work and compare simulations ,then discussion the results, also it should be including "good lectures view" ,introduction, abstract ,reference, figures ,etc.
the topic about “Estimation of the Performance of Closed Longitudinal Ribs Orthotropic Bridge deck sections on Stress Distribution" and there is no problem if the experts play with the name topic but it should taking about Closed Longitudinal Ribs Orthotropic Bridge deck .There is a lot of articles available in the internet about this topic it will help the experts to make good research about this idea. I want this article including more detail also it's recommended to write an article towards the 2000 word count with pretty pictures to make it easier to understand. Avoid verbal diarrhea and get straight to the point. But it all depends on your expert’s situation. On your expert’s style, I need the results easy to understand covering a topic.
Microsoft Word - numero 9 art 11 finale Z.H. Qian et alii, Frattura ed Integrità Strutturale, 9 (2009) 105 - 112; DOI: 10.3221/IGF-ESIS.09.11 105 Fatigue failure of welded connections at orthotropic bridges Z.H. Qian, D. Abruzzese University of Rome “Tor Vergata”, Department of Civil Engineering, Rome (Italy) RIASSUNTO. Le piastre ortotrope sono state applicate ai ponti di grande luce a partire dal periodo immediatamente successivo alla Seconda Guerra mondiale a causa dei numerosi vantaggi che esse presentano, come il peso contenuto, l'elevata resistenza, il ridotto numero di connessioni con l'impalcato, la durabilità, la rapidità costruttiva e l’economia dovuta alla manutenzione durante il ciclo di vita. Lo studio della fatica nelle piastre ortotrope è iniziato circa venti anni fa, da quando sono state diagnosticate le prime rotture per fatica. Da allora sono stati condotti un vasto numero di studi e indagini, ottenendo risultati interessanti. Si è scoperto che la maggior parte delle rotture per fatica si verificano in corrispondenza delle connessioni saldate, ovvero le giunzioni rib-to-deck, rib-to-diaphragm, e rib-to-diaphragm-to-deck (plate) (RDDP). Questa tipologia di connessioni è sensibile alla nascita di fratture per fatica dovute agli accumuli di tensione ed alle tensioni residue nelle connessioni saldate. In questo articolo viene presentato e analizzato un caso studio di rottura a fatica nelle connessioni saldate, dove è più probabile una frattura, attraverso una modellazione numerica di una piastra ortotropa con un software ad elementi finiti (FE). Inoltre viene affrontato il tema del miglioramento delle tecnologie adottate per limitare i problemi di fatica. I risultati di queste analisi possono rappresentare un proficuo contributo per la progettazione a fatica delle piastre ortotrope. ABSTRACT. Orthotropic decks were applied to the long span bridges after World War II due to several advantages, such as light weight, high strength, few deck joints, durability, rapid construction, life-cycle economy. The fatigue problem of orthotropic decks was realized twenty years ago since fatigue failure was found. In the past two decades large amount of studies and investigations were carried out and fruitful achievements were obtained. It was found that most of the fatigue cracks were occurred at the welded connection details, such as rib-to-deck plate, rib-to-diaphragm, and rib-to-diaphragm-to-deck plate (RDDP). These connections are sensitive to fatigue cracking due to high concentrated stress and residual stress at welded connections. In this paper practical fatigue failure cases at the welded connections, ease to occur fatigue cracking, are presented, and analyzed through a numerical modeling of orthotropic deck via FE (finite element) software. Furthermore, the improvement technologies of fatigue are also discussed. The results of the analysis can be contributed to the evaluation of the fatigue design for the orthotropic deck. KEYWORDS. Fatigue failure; Welded connection; Orthotropic deck; Numerical modeling; Rib-to-deck plate connection. INTRODUCTION atigue cracking is a common problem in steel structures for a long time due to the existing of welded connections. According to the practical cases, most of fatigue failures occurred at welded components since high residual stress and inherent defects existed [1]. Since from 1960 a number of bridge structures in America and Europe have experienced fatigue cracking which sometimes results brittle fractures, fatigue problem in steel bridges has been started to be investigated for many years and produced fruitful achievements. F http://www.gruppofrattura.it/ http://dx.medra.org/10.3221/IGF-ESIS.09.11&auth=true Z.H. Qian et alii, Frattura ed Integrità Strutturale, 9 (2009) 105 - 112; DOI: 10.3221/IGF-ESIS.09.11 106 From the British Standard BS5400 is one of the most important specifications in the last century [2], and recently, some new specifications or standards were accomplished, such as Eurocode3 (2004) [3] and AASHTO (2005) [4]. These specifications provide a mass of information to design steel bridges. Among of these, Eurocode 3 and AASHTO already have some specific guidelines to orthotropic deck bridges. S-N curves in Eurocode 3, for fatigue design, are shown in Fig. 1. Figure 1: Fatigue strength curves for direct stress ranges (Eurocode3, 2004). The orthotropic deck is consisted by a deck plate supported in two mutually perpendicular directions by transverse diaphragms (or crossbeam) and longitudinal stiffeners (or ribs). It is effectively an ORTHOgonal anisoTROPIC (orthotropic) deck. Orthotropic deck is widely utilized for long span bridges in recent decades with the development of computing methodologies and fabricating technologies. It was first used in Germany after the Second World War in order to reduce the construction material, since steel being in short. Nowadays, orthotropic deck bridges are very popular in Europe, particular in Germany. Meanwhile, more and more orthotropic bridges are being built in China, Japan, U.S.A., and other countries. Orthotropic deck has many advantages, main of one is the light weight, high strength, few deck joints, durability, rapid construction and life-cycle economy. However, fatigue problem is unavoidable at orthotropic deck bridges due to the complex structure and the large number of welded connections. Fig. 2 shows a summary of welded connection details at orthotropic deck bridges [5]. It is obvious that most of these are potentially liable to cause fatigue cracking taking account into concentrated stress and residual stress in welded connections. In the past years various technologies were studied to improve the fatigue performance of welded joints. The fatigue life can be increased through surface treatment, reducing residual stress as well as optimizing design of structure. Among of these, peening, as a cold treatment technology, is one of the most widely utilized in engineering, bringing better surface properties and producing beneficial compressive stress [6]. Both of them can improve the fatigue strength of welded connections. This last technology is still highly improving. Figure 2: Main welded connections in a typical orthotropic bridge deck (Gurney, 2006) http://www.gruppofrattura.it/ http://dx.medra.org/10.3221/IGF-ESIS.09.11&auth=true Z.H. Qian et alii, Frattura ed Integrità Strutturale, 9 (2009) 105 - 112; DOI: 10.3221/IGF-ESIS.09.11 107 In this paper, the fatigue failures at orthotropic deck bridges are discussed based on the previous investigations. The sensitive connection details to fatigue cracking, rib-to-deck plate, rib-to-diaphragm and rib-to-diaphragm-deck plate, are emphasized through practical cases and numerical analysis. Furthermore, the three improvement techniques, shot peening, fluid bed peening (FBP) and ultrasonic impact treatment (UIT) are detailed presented. This study aims to contribute to the design and reinforcement of orthotropic deck bridges. RIB-TO-DECK PLATE CONNECTION ib-to-deck plate connections are submitted to local transverse bending moments and are therefore susceptible to fatigue cracking. The connections have been studied for a long time, particular in recent years. Fig. 3 shows fatigue cracking at rib-to-deck plate connection [7]. The fatigue tests to rib-to-deck plate connection were carried out by Janss in 1980 in Belgium [8]. Thirty-three small test specimens were manufactured and tested at a frequency of 4Hz. Figure 3: Fatigue cracks at rib-to-deck plate connection (Xiao, 2008). Through the investigation, it was concluded that the stress range at two million cycles of the transverse stresses at the weld toe in the rib is equal to 80 N/mm2 when trapezoidal ribs with a thickness of 6mm are welded to deck plates with a thickness of 12mm and the gap between the rib and the deck plate does not exceed 0.5mm. The stress range (80 N/mm2), mentioned above, is certainly a lower limit due to the poor quality of the welds of the test pieces. Based on the investigations of Janss and the others, ECSC research carried out on the optimization of the welding procedure (automatic welding) and the influence of a gap, 0 or 2mm, between the rib and the deck plate [9]. The specimens used in the ECSC experiments were welded with automatic submerged arc welding in an industrial situation. It was found that full penetration welds with a lack of penetration less than 1mm can nearly be achieved without edge preparation. Meanwhile, the fatigue strength significantly increases when using submerged arc welding, which allows larger penetration and larger throat of the weld. With the development of the compute technology, more and more numerical studies are put into practice. Finite element analysis (FEA) provides more results to details compared to the traditional method, such as P-E method. Stress distributions of three different loadcases at the deck plate were shown in Fig. 4 [10]. From the figure, two obvious differences can be concluded. The first one is that the range of high stress is much different, and loadcase1 is larger than the other two. The second one is that both maximal and minimal stresses of loadcase2 and loadcase3 are much higher than loadcase1. The stresses far from the vehicle appear like waves due to the restriction of longitudinal ribs, and are almost zero. Another important point should be noted is that the peak stresses of all these there different loadcases produced near or exactly at the rib-to-deck plate connections. For loadcase1, symmetrical loading, both maximal and minimal stress are exactly at the connections, while for loadcase2 and loadcase3, asymmetrical loading, the maximal stresses are produced at the middle