Comment on: Toughness of Railroad Concrete Crossties with Holes and Web Openings. Infrastructures 2017, 2, 3

Abstract

The present brief comment is regarding the technical note "Toughness of railroad concrete crossties with holes and web opening", by Erosha K. Gamage, Sakdirat Kaewunruen, Alex M. Remennikov, and Tetsuya Ishida [1].I judge from my experience (please see some of my relevant publications [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] about loading and dimensioning of concrete sleepers; uploaded in http://giannakoskonstantinos.com/wp) that their technical note is of little value since it does not include dynamic testing of the sleepers/crossties, but it is based only on static tests. I briefly describe the research performed with me as the coordinator, for a period of over twenty years.The investigation of railway matters in Greece had been undertaken during the development of the Greek Railways' network and the design, construction, and maintenance of new and upgraded (high-speed) lines planned for operational speeds of up to 250 km/h (155 m/h) and axle-load max = 22.5 t; this development has been co-financed by European Union/EU and the Greek Government, since the 1980s, and it is performed according to the EU's regulations and technical specifications. This decision (of increasing the permissible maximum operational speed in the network) resulted in a huge research program, in order to adapt the entire railway system to the needs of the High-Speed networks. The research program-extending over twenty years in total, in collaboration with universities in Greece (National Technical University of Athens/NTUA, Professor Th.P. Tassios; Aristotle University of Thessaloniki, Professor Tsotsos) and abroad (Graz University, Professor K. Riessberger; Munich Technical University, Professor G. Leykauff, etc.) and with research teams from research institutes: Institute of Geological and Mineral Research/IGME, initials of the relevant Greek words, Center of Research of Public Works, of the Ministry of Public Works/KEDE, initials of the relevant Greek words, in Greece and European State railway networks (French/SNCF and Sofrerail, Belgian/SNCB-Transurb Consult, German/DB, etc.)-led to the development of highly respected know-how and new fields of scientific knowledge. One of the main problems observed-before the research program-was the cracking of the concrete sleepers and the implied deterioration of the geometry of the track. Of the U2/U3 Vagneux type twin-block concrete sleepers (produced in Greece with the license and responsibility of the French company which produced them for the SNCF) laid on track, 60% or more exhibited cracks in the Greek network, at a position under the rail, propagating upwards from the lower seating surface of the sleeper on the ballast. It is noted that the same sleeper type in the French Railway network (maximum operational speed 200 km/h, daily tonnage 50,000 t) did not exhibit any problems at all. In Greece-at that time-the maximum operational speed was 140 km/h, daily tonnage 10,000 t, and Co-Co diesel locomotives were used of approximately 21 t/axle static load.The existing inter...

Reply to Giannakos, K. Comment on: Toughness of Railroad Concrete Crossties with Holes and Web Openings. Infrastructures 2017, 2, 3

“…This paper responds to the discussion [1] by Dr. K. Giannakos over our technical note [2]. In fact, the authors welcome any comments to improve our research and practical experience related to railway sleepers.…”

“…The toughness characteristic has correlation with dynamic strength and endurance of structural members. In the technical note [1], the emphasis was placed on experimental investigations into structural toughness, which is an important characteristic to predict failure under ultimate and damageability limit states [39, 85,135]. As such, there is no shortage of value since the research in [2] paves the essential fundamental for further research into sleepers' retrofit and modification.…”

“…Without appropriate structural design and engineering analysis, the structural safety and engineering reliability of railway track systems can be impaired or mismanaged. A critical review of existing standard design codes (e.g., European Standard EN13230-2, American Standard AREMA C4, Australian Standard AS1095.14, or American Concrete Institute, ACI) reveals that there is a necessity to investigate such the important aspects [1]. On this ground, it is important to note that it is the first time that the effect of holes and web openings on the toughness and ductility of concrete sleepers is addressed in a systematic way [2].…”

“…In fact, the authors welcome any comments to improve our research and practical experience related to railway sleepers. In the discussion comment letter [1], Dr Giannakos discussed whether or not static testing of railway prestressed concrete sleepers has any value in the engineering field. The discusser based his comments on the need for dynamic testing for the determination of the bearing capacity of concrete sleepers on the provisions from EN13230-2 and also inappropriately stated that 'it is misleading to use static not dynamic tests'.…”