University of Architecture, Civil Engineering and Geodesy (UACEG)

– Metal Structures for students in Structural Engineering

– Steel and Composite Bridges for students in Structural Engineering

– Steel Structures of Thin-Gauged Cold-Formed Members (elective course) for students in Structural Engineering

 1. Sotirov P., Bonev Z., Rangelov N., Milev J., Georgiev Tzv., Ganchev O., “RECOS: Reliability of Moment Resistant Connections of Steel Building Frames in Seismic Areas”. European research project with coordinator Prof. Federico Mazzolani (Naples), and partners from 8 European countries, 1997–1999 (team member).
2. Rangelov N., Georgiev L., Ivanov St., Ganchev O., Boshnakov D., Jordanova K., Gürov V., “Investigation of the behaviour composite steel-concrete beams with partially encased profiles under static loading”, Research project under contract БН-125/11, Research Centre at UACEG, 2011-2012 (research responsible).
3. Rangelov N., Raykov St., Ganchev O., Dojkov Iv., Danailov D., “Investigation of the behaviour of steel column bases under cyclic loading”, Research project under contract БН-143/13, Research Centre at UACEG, 2013 (research responsible).
4. Rangelov N., Ganchev O., Mladenova R., Ivanov St., “Experimental study of frame knee joints between thin-gauged cold-formed members”, Research project under contract Д-62/14, Research Centre at UACEG, 2014 (research responsible).
5. Rangelov N., Georgiev Tzv. et al., ”INNOSEIS: Valorization of innovative anti-seismic devices”. European research project under the Research fund for coal and steel of the European Commission, with coordinator Prof. Ioannis Vayas (NTUA, Athens), partners from 8 European universities and ECCS (research responsible for UACEG team), 2016-2017.

6. Rangelov N., Penelov Ch. et al., "EQUALJOINTS PLUS: Valorisation of knowledge for European pre-qualified steel joints”. European project (RFCS) with coordinator Prof. Raffaele Landolfo (Universitá di Napoli Federico II), partners from 13 universities, industry and ECCS (research responsible for UACEG team), 2017-2019.

7. Rangelov N., Penelov Ch., Hadzhijaneva I., Radoslavov, G., “FREEDAM PLUS: Valorisation of knowledge for FREE from DAMage steel connections”. European project (RFCS) with coordinator Prof. Vincenzo Piluso (Università degli studi di Salerno), partners from 13 universities and ECCS (research responsible for UACEG team), 2020-2022.

1. Rangelov N., Georgiev Tzv. et al., “INNOSEIS: Valorization of innovative anti-seismic devices”. European research project under the Research fund for coal and steel of the European Commission, with coordinator Prof. Ioannis Vayas (NTUA, Athens), partners from 8 European universities and ECCS (research responsible for UACEG team), 2016-2017.
2. Rangelov N., Penelov Ch., Hadzhijaneva I., Radoslavov, G., EQUALJOINTS PLUS: Valorisation of knowledge for European pre-qualified steel joints”. European project (RFCS) with coordinator Prof. Raffaele Landolfo (Universitá di Napoli Federico II), partners from 13 universities, industry and ECCS (research responsible for UACEG team), 2017-2019.
3. Rangelov N., Penelov Ch., Hadzhijaneva I., Radoslavov, G., “FREEDAM PLUS: Valorisation of knowledge for FREE from DAMage steel connections”. European project (RFCS) with coordinator Prof. Vincenzo Piluso (Università degli studi di Salerno), partners from 13 universities and ECCS (research responsible for UACEG team), 2020-2022.

1. Rangelov N., “Parametric study on imperfect steel compressed plates and a proposal for a new varying out-of-flatness tolerance”, Proceedings of the 1st Sofia-Kyoto University Joint Seminar on Civil Engineering, Sofia, 1990, pp. 74-76.
2. Linkov G., Ivanov I., Alexiev G., Rangelov N., Mihaylov R., “Design approaches for some type of buildings with steel structures”, Proceedings of the 1st Sofia-Kyoto University Joint Seminar on Civil Engineering, Sofia, 1990, pp. 77-79.
3. Rangelov N., “Theoretical study of the post-buckling behaviour of steel plates with initial imperfections”, Stroitelstvo, Sofia, vol. 38 (1991), no 1-2, pp. 14-18 (in Bulgarian).
4. Rangelov N., Linkov G., “Initial deflections and their effect on the resistance of compressed steel plates”, Stroitelstvo, vol. 38 (1991), no 4, pp. 3-6 (in Bulgarian).
5. Rangelov N., “On the uniaxially compressed steel plates with initial out-of-flatness”, Stroitelstvo, vol. 38 (1991), no 5-6, pp. 16-20 (in Bulgarian).
6. Linkov G., Rangelov N., “On the design of steel crane runway girders in the case of large number of loading cycles” , Stroitelstvo, vol. 39 (1992), no 1, pp. 6-8 (in Bulgarian).
7. Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), H. 5, pp. 151-156.
8. Rangelov N., “More on the initial imperfections in steel plated members”, Proceedings of Conference “Building Structures of Steel and Wood”, Institute of Architecture and Civil Engineering (VIAS), Sofia, 1993, pp. 8-14 (in Bulgarian).
9. Rangelov N., “On the effective stiffness of thin-walled steel members”, Stroitelstvo, vol. 41 (1994), no 8-9, pp. 12-15 (in Bulgarian).
10. Rangelov N., “Ultimate state behaviour of compressed steel plates with initial imperfections”, Annuaire de l’Institut d’Architecture et de Génie Civil, Sofia, vol. XXXVII (1994), fasc. V, pp. 107-123 (in Bulgarian).
11. Braham M., Maquoi R., Rangelov N., Richard Ch., “L’influence des défauts de planéité de l’âme des profilés reconstitués soudés sur leur résistance en flexion et compression”, Construction Métallique, no 1, 1995, p. 3-28.
12. Rangelov N., Braham M., “Are the web imperfections in built-up I-beams of any importance ?”, International Colloquium — European Session: “Stability of Steel Structures”, Budapest, Sept. 1995, vol. I, pp. 263-270.
13. Rangelov N., Braham M., “Influence of web initial imperfections on the load carrying capacity of steel members”, Stroitelstvo, vol. 42 (1995), no 6, pp. 17-21 (in Bulgarian).
14. Rangelov N., “On the effective stiffness of slender steel sections for deflection calculations”, Thin-Walled Structures, vol. 25 (1996), № 3, pp. 171-184.
15. Rangelov N., “Girders with slender webs having large initial out-of-flatness”, Stroitelstvo, vol. 44 (1997), no 3-4, pp. 13-18 (in Bulgarian).
16. Rangelov N., “Effect of initial imperfections (residual stresses and out-of-flatness) on the local behaviour and resistance of welded I-girders with slender webs”, Annuaire de l’Université d’Architecture, de Génie Civil et de Géodesie, Sofia, vol. XXXIX (1998), fasc. VII, pp. 103-114 (in Bulgarian).
17. Braham M., Rangelov N., “The influence of web undulations on the section resistance of slender I-beams”, Proceedings of the Conference “Eurosteel ’99”, ČVUT Praha, May 1999, pp. 215-218.
18. Rangelov N., “Influence of web imperfections in welded I-beams with slender webs”, Proceedings of the 6th International Colloquium on Stability & Ductility of Steel Structures, (edited by D. Dubină and M. Iványi), Timişoara, September 1999, pp. 175-182.
19. Sotirov P., Rangelov N., Ganchev O., Georgiev Tz., Petkov Z.B. and Milev J., “Improved beam-to-column joints for moment-resisting frames – an experimental study”, Proceedings of the 6th International Colloquium on Stability & Ductility of Steel Structures, (edited by D. Dubină and M. Iványi), Timişoara, September 1999, pp. 241-248.
20. Milev J., Petkov Z.B., Sotirov P., Rangelov N. and Georgiev Tz., “Energy based methods and time history response analysis for behaviour factor evaluation of moment-resisting steel frames” Proceedings of the 6th International Colloquium on Stability & Ductility of Steel Structures, (edited by D. Dubină and M. Iványi), Timişoara, September 1999, pp. 421-428.
21. Vayas I., Rangelov N. and Georgiev Tz., “Schlankheitsanforderungen zur Klassifizierung von Trägern aus I-Querschnitten”, Stahlbau 68 (1999), H. 9, pp. 713-724.
22. Stajkov P. and Rangelov N., “Reconstruction of the railway bridge over Sava river near Jasenovac, Croatia”, Proceedings of the 8th International Symposium of MASE, Ohrid, 30 September — 2 October 1999, pp. СТ 33 / 1–5 (in Bulgarian).
23. Sotirov P., Rangelov N. and Milev J., “Improvement of seismic behaviour of beam to column joints using tapered flanges”, Proceedings of the Third International Conference “Behaviour of Steel Structures in Seismic Areas” (STESSA 2000), Montréal, August 2000, ed. by F.M. Mazzolani & R. Tremblay, Balkema, Rotterdam, pp. 265–270.
24. Milev J., Sotirov P. and Rangelov N., “Energy based methods for evaluation of behaviour factor for moment resisting frames”, Proceedings of the Third International Conference “Behaviour of Steel Structures in Seismic Areas” (STESSA 2000), Montréal, August 2000, ed. by F.M. Mazzolani & R. Tremblay, Balkema, Rotterdam, pp. 619–626.
25. Vayas I., Rangelov N., “Classification of beams with box sections”, Proceedings of the Third International Conference on Coupled Instabilities in Metal Structures (CIMS 2000), Lisbon, September 2000, ed. by D. Camotim, D. Dubina & J. Rondal, Imperial College Press, London, pp. 681-688.
26. Sotirov P., Rangelov N., Ganchev O., Georgiev Tzv., Milev J., Petkov Z., “Influence of haunching”. Chapter 3.3 in Moment Resistant Connections of Steel Frames in Seismic Areas (edited by F.M. Mazzolani), E & FN Spon, London, 2000. pp. 245-265.
27. Milev J., Sotirov P., Bonev Z., Rangelov N., Georgiev Tzv., “Energy approach”. Chapter 8.2 in Moment Resistant Connections of Steel Frames in Seismic Areas (edited by F.M. Mazzolani), E & FN Spon, London, 2000. pp. 579-595.
28. Milev J., Sotirov P., Bonev Z., Rangelov N., Georgiev Tzv., “Comparison among methods”. Chapter 8.4 in Moment Resistant Connections of Steel Frames in Seismic Areas (edited by F.M. Mazzolani), E & FN Spon, London, 2000. pp. 617-628.
29. Braham M., Rangelov N., “Lateral-torsional buckling of steel I-section beams – some comments on the Eurocode 3 approach” Stroitelstvo, No 1/2001, pp. 2-9 (in Bulgarian).
30. Vayas I., Rangelov N., “Classification of girders with I- or box cross-sections”, International Journal of Steel Structures, KSSC, Seoul, vol. 1 (2001) No.3, pp.153-165.
31. Rangelov N., Enchev Al., Milev J., Sotirov P., “Finite element analysis of ductile steel moment resisting beam-to-column joints”, Proceedings of Jubilee Scientific Conference “60 years UACEG”, Sofia, Nov. 2002, Vol. 3, pp. 181-189 (in Bulgarian).
32. Sotirov P., Georgiev Tzv., Rangelov N., “Seismic performance of ductile moment resisting steel frames”, Proceedings of Jubilee Scientific Conference “60 years UACEG”, Sofia, Nov. 2002, Vol. 3, pp. 209-220 (in Bulgarian).
33. Rangelov N., “Facility Building of PERI Bulgaria – an efficient design solution”, Proceedings of Third national conference with international participation “Design and Construction of Buildings and facilities (DCB 2004), Plovdiv, Bulgaria, 7-9 October 2004 (in Bulgarian).
34. Rangelov N., “Aspects of the design of steel plated structures and bridges according to Eurocode 3”, Annuaire de l’Université d’Architecture, de Génie Civil et de Géodesie, Sofia, vol. XLII (2005/06), fasc. VIIa, pp. 25-34 (in Bulgarian).
35. Rangelov N., “Application of efficient design solutions with steel structures for industrial buildings”, Proceedings of the International Conference UACEG 2009: Science & Practice, Sofia, 29-31 October 2009 (in Bulgarian).
36. Ivanov St., Georgiev L., Rangelov N., „Bending resistance of composite girders with partially encased steel profiles according to Eurocode 4”, Annuaire de l’Université d’Architecture, de Génie Civil et de Géodesie, vol. XLV (2011/2012), fasc. VIII, pp. 143-152, Sofia, 2012.
37. Ivanov St., Georgiev L., Rangelov N., “Experimental investigation of the bond connection of partially encased steel I-girders loaded in bending”, Proceedings of the International conference on Civil Engineering Design and Construction (DCB2012), Varna, 13-15 September, 2012, pp.281-287.
38. Ivanov St., Georgiev L., Rangelov N., “Computer modelling of experimentally tested beams consisting of partially encased steel I-girders loaded in bending”, Proceedings of International Jubilee Conference UACEG2012: Science & Practice, 15-17 November, 2012, pp. 381-388.
39. Ivanov St., Georgiev L., Rangelov N., “Experimental determination of bending resistance of composite girders with partially encased steel profiles”, Annual of the University of Architecture, Civil Engineering and Geodesy, vol. XLVI (2012/2013), fasc. VIII, pp. 121-128.
40. Raykov St., Ganchev O., Danailov D., Dojkov Iv., Rangelov N., “Full-sale experimental study on exposed steel column bases”, Annual of the University of Architecture, Civil Engineering and Geodesy, vol. XLVI (2013/2014), fasc. IX-A, pp. 141-154.
41. Rangelov N., Ivanov St., Raykov St., “Recent research activities at the Department of Steel Structures, UACEG, Sofia”, Proceedings of 8th Hellenic National Conference on Steel Structures, Tripoli, Greece, 2-4.10.2014.
42. Rangelov N., „Some specific problems in application of steel structures for industrial buildings“, Annual of the University of Architecture, Civil Engineering and Geodesy, vol. XLVI (2014), fasc. XI, Sofia, 2015, pp. 7--17.
43. Rangelov N., Vasilev M., „Stability of purlins under wind suction“, Annual of the University of Architecture, Civil Engineering and Geodesy, vol. XLVI (2014), fasc. XI, Sofia, 2015, pp. 141-152.
44. Mladenova R., Rangelov N., „Numerical analysis of frame knee joints between thin-gauged cold-formed members“, Annual of the University of Architecture, Civil Engineering and Geodesy, vol. XLVI (2014), fasc. XI, Sofia, 2015, pp. 189-198.
45. Boshnakov S., Rangelov N., „A case study on the wind loading effects on a cable-stayed bridge“, Annual of the University of Architecture, Civil Engineering and Geodesy, vol. XLVI (2014), fasc. XI, Sofia, 2015, pp. 169-177.
46. Mladenova R., Rangelov N., Ganchev O., „Experimental study of frame knee joints between thin-gauged cold-formed members“, Annual of the University of Architecture, Civil Engineering and Geodesy, vol. XLVIII (2014-15), fasc. VIII-A, Sofia, 2015, pp. 101-110.
47. Georgiev Tzv., Rangelov N., “Introduction of Eurocodes in Bulgaria and implementation of Eurocode 3”, Proceedings of the 16th International Symposium of MASE, Ohrid, 1-3.10.2015, pp. 169-180.
48. Rangelov N., „Steel structures of thin-gauged cold-formed members. Theoretical backgrounds and design according to BDS EN 1993-1-3 and BDS EN 1993-1-5”, KIIP Sofia, 2015, ISBN: 978-619-90034-0-4.
49. Tzv. Georgiev, L. Raycheva, D. Zhelev, N. Rangelov, Chapter 9: „Concentrically braced frames with modified braces (CBF-MB)”, Book Title „INNOVATIVE ANTI-SEISMIC DEVICES AND SYSTEMS“, edited by Ioannis Vayas, pp. 269-310, ECCS, 2017; ISBN: 978-92-9147-136-2.
50. Konstantinos Bakalis, Dimitrios Vamvatsikos, Lora Raycheva, Tzvetan Georgiev, Dimo Zhelev, Nikolaj Rangelov, Chapter 10 of „Validation of q-factors for innovative devices“, INNOSEIS – Valorization of innovative anti-seismic devices, 2017, www.innoseis.ntua.gr.
51. Tzvetan Georgiev, Dimo Zhelev, Lora Raycheva, Nikolaj Rangelov, Chapter 10 of „Volume on case studies for low-rise buildings“, INNOSEIS – Valorization of innovative anti-seismic devices, 2017, www.innoseis.ntua.gr.
52. Tzvetan Georgiev, Dimo Zhelev, Lora Raycheva, Nikolaj Rangelov, Chapter 10 of „Volume on case studies for mid/high-rise buildings“, INNOSEIS – Valorization of innovative anti-seismic devices, 2017, www.innoseis.ntua.gr.
53. Tzvetan Georgiev, Nikolaj Rangelov, Lora Raycheva, Stanislav Raykov, Chapter 9 of „Volume with pre-normative design guidelines for innovative devices“, INNOSEIS – Valorization of innovative anti-seismic devices, 2017, www.innoseis.ntua.gr.
54. Vassilev M., N. Rangelov, „Stability problems of single storey steel frames (Part 1)", Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 51 (2018) 4.
55. Vassilev M., N. Rangelov, „Stability problems of single storey steel frames – application of general method and GMNIA (Part 2)", Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 51 (2018) 4.
56. Vassilev M., N. Rangelov, "Experimental study on the out-of-plane stability of steel portal frames", Proceedings of XVIII Anniversary International Scientific Conference "Construction and Architecture" VSU'2018, Sofia, Oct. 2018.
57. Penelov Ch., I. Hadzhiyaneva, N. Rangelov, "A numerical study on the seismic response of a six-storey steel eccentrically braced dual system with equal strength joints", Proceedings of XVIII Anniversary International Scientific Conference "Construction and Architecture" VSU'2018, Sofia, Oct. 2018.
58. Penelov Č, N. Rangelov, “Seismic response of steel dual eccentrically braced frames with equal-strength joints”, in Stability and Ductility of Steel Structures 2019 (Ed. by F. Wald & M. Jandera), CRC Press / Balkema, Taylor & Francis Group, ISBN 978-0-367-33503-8, 2019, pp. 890-897.
59. Vassilev M., N. Rangelov, “Study on the out-of-plane stability of steel portal frames”, in Stability and Ductility of Steel Structures 2019 (Ed. by F. Wald & M. Jandera), CRC Press / Balkema, Taylor & Francis Group, ISBN 978-0-367-33503-8, 2019, pp. 1201-1209.
60. Rangelov N., L. Zdravkov, “Pedestrian Bridge over Nikola Mushanov Blvd. Condition of the bearing structure”, Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 54 (2021) 3, pp. 429-445.
61. Rangelov N., D. Dinev, G. Radoslavov, “Application of nonlinear analysis GMNIA for assessment of an irregular steel structure”, Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 54 (2021) 3, pp. 515-523.
62. Rangelov N., “Structural condition of Vartopo bridge in Sofia: Discussion and recommenda-tions”, Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 54 (2021) 3, pp. 525-535.
63. Raykov St., N. Rangelov, D. Dinev, “Behaviour of tall chimneys with steel supporting structure under wind action. Part 1: The problem”, Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 54 (2021) 3, 537-552.
64. Raykov St., N. Rangelov, D. Dinev, “Behaviour of tall chimneys with steel supporting structure under wind action. Part 2: The solution”, Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 54 (2021) 3, 553-562.
 

CITATIONS:

1. Dankov E., „Application of the consequential approach method to the analysis of buckling and postbuckling equilibrium“, PhD Thesis, UACEG, Sofia, 1992 (in Bulgarian).
cites as [18] Rangelov N., “Theoretical study of the post-buckling behaviour of steel plates with initial imperfections”, Stroitelstvo, Sofia, vol. 38 (1991), no 1-2, pp. 14-18.
2. Sadovský Z., Balaž I., “Höchstwerte von Vorverformungen des Stegblechs und Festigkeit eines Dünnwandigen I-Querschnittes bei Biegemoment- und Druckbeanspruchung“. Stahlbau, vol. 64 (1995) H. 3, pp. 69–77.
cites as [8] Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), H. 5, pp. 151-156.
3. Sadovský Z., Balaž I., “Strength based tolerances of initial deflections of steel plates“. Proceedings of the IXth International Conference on Metal Structures, Kraków, June 1995, pp. 131–138.
cites as [1] Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), H. 5, pp. 151-156.
4. Sadovský Z., Balaž I., “Tolerances of initial deflections of steel plates and strength of I cross-section in compression and bending“.Journal of Constructional Steel Research, vol. 38 (1996) No. 3, pp. 219–238.
cites as [8] Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), H. 5, pp. 151-156.
5. Pasternak H., Schilling S., Engst W., “How welding does influence the ultimate load capacity of thin-walled structural members – an example“.European Workshop “”Thin-Walled Steel Structures”, Krzyżowa (Kreisau), Poland, Sept. 1996, pp. 135–142.
cites as [4] Rangelov N., Braham M., “Are the web imperfections in built-up I-beams of any importance ?”, International Colloquium — European Session: “Stability of Steel Structures”, Budapest, Sept. 1995, vol. I, pp. 263-270.
6. Vašek M., “The influence of imperfections on the behaviour of one-side welded I-beams“. Proceedings of the Conference Ëurosteels ’99”, ČVUT Praha, 1999, pp. 211–214.
cites as [1] Braham M., Maquoi R., Rangelov N., Richard Ch., “L’influence des défauts de planéité de l’âme des profilés reconstitués soudés sur leur résistance en flexion et compression”, Construction Métallique, no 1, 1995, p. 3-28.
7. Plumier A., “General report on local ductility”, Journal of Constructional Steel Research, vol. 55 (2000) No. 1-3, pp. 91–107.
cites as [16]: Sotirov P., Rangelov N., Ganchev O., Georgiev T., Milev J., Petkov Z., „Improved beam to column joints for moment resisting frames—an experimental study“, RECOS Progress Report, University of Sofia, 1999.
8. Blagov D., „Assessment of the nonlinear behaviour of frames under seismic actions“, PhD Thesis, UACEG, Sofia, 2002 (in Bulgarian).
cites as [144]: Sotirov P., N. Rangelov, J. Milev, Tz. Georiev, O. Ganchev, Z. Petkov, Project COPERNICUS-RECOS, 1999.
9. Dakov D., Al. Enchev, „Restoration, strengthening and retrofit of steel structures“, «А®ВС Tehnica», Sofia, 2002 (in Bulgarian).
cites as [39]: Sotirov P., Rangelov N., Ganchev O., Georgiev Tz., Petkov Z.B. and Milev J., “Improved beam-to-column joints for moment-resisting frames – an experimental study”, Proceedings of the 6th International Colloquium on Stability & Ductility of Steel Structures, Timişoara, 1999.
10. Mazzolani F.M., “Steel and Composite Structures in European Seismic Areas: Research, Codification, Design, and Applications”, Earthquake Spectra, vol. 19 (2003) No. 2, pp. 415-452.
cites: Sotirov P., Rangelov N., Ganchev O., Georgiev Tz., Petkov Z. B., Milev J., “Improved beam-to-column joints for moment-resisting frames: An experimental study”, Proc. of 6th International Colloquium on Stability and Ductility of Steel Structures (SDSS’99), Elsevier (Dubina and Ivanyi, eds), Timisoara, Romania, 9–11 September 1999.
11. Kala Z., Kala J., Škaloud M., Teplý B., Melcher J., Novák D., “Sensitivity analysis of engineering structures”, Proc. of European Congress on Computation Methods in Applied Science and Engineering ECCOMAS 2004 (P. Neittaanmäki, T. Rossi, K. Majava, O. Pironneau, eds., I. Lasiecka, assoc. ed.), Jyväskylä, 24-28 July 2004.
cites as [13]: Rangelov N., “Influence of web imperfections in welded I-beams with slender webs”, in Proceedings of SDSS’99 (edit. D. Dubina and M. Iványi), 1999, Elsevier Science Ltd., pp. 175-182.
12. Enchev Al., „Strengthening of structures with steel skeleton“, PhD Thesis, UACEG, Sofia, 2004 (in Bulgarian).
cites as [72]: Sotirov P., Rangelov N., Ganchev O., Georgiev Tz., Petkov Z.B. and Milev J., “Improved beam-to-column joints for moment-resisting frames – an experimental study”, Proceedings of the 6th International Colloquium on Stability & Ductility of Steel Structures, (edited by D. Dubinâ and M. Iványi), Timişoara, September 1999, pp. 241-248.
13. Kala Z., Kala J., Škaloud M., Teplý B., “Sensitivity analysis of the effect of initial imperfections on the (i) ultimate load and (ii) fatigue behaviour of steel plate girders”, Journal of Civil Engineering and Management, vol. XI (2005) No.2, pp. 99-107.
cites as [7]: Rangelov N., “Influence of web imperfections in welded I-beams with slender webs”, in Proceedings of SDSS’99 (edit. D. Dubina and M. Iványi), 1999, Elsevier Science Ltd., p. 175-182.
14. Sanchez-Ricart L., A. Plumier., “Parametric study of ductile moment-resisting frames. First step for Eurocode 8 calibration”, Earthquake Engineering & Structural Dynamics, Vol. 37, Issue 7, June 2008, pp. 1135–1155.
cites as [39]: Sotirov P., Rangelov N., Ganchev O., Georgiev Tzv., Milev J., Petkov Z., Chapter 3: Cyclic behaviour of beam-tocolumn bare steel connections, 3.3 “Influence of haunching”, Moment Resistant Connections of Steel Frames in Seismic Areas, E & FN Spon, 2000, pp. 245-265.
15. Škaloud M., Melcher J., Kala J., Kala Z., “A way to economic fabrication steel construction – is the straightening of plate elements really indispensable and desirable?”, 22. Česka a Slovenska konference, Brno, 23-25.09.2009, pp. 285-292.
cites as [2]: Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), pp. 151-156.
16. Zhang S.Y., Prater Jr. G., „A study of the effect of elastic instability on stiffness-based gauge sensitivity indices for vehicle body structure assessment”, Thin-Walled Structures, Vol. 47 (2009) 12, pp. 1590-1596.
cites as [17]: Rangelov N., “On the effective stiffness of slender steel sections for deflection calculations”, Thin-Walled Structures, Vol. 25 (1996) 3, pp. 171-184.
17. Sang Whan Han, Ki-Hoon Moon, Božidar Stojadinović, “Design equations for moment strength of RBS-B connections”, Journal of Constructional Steel Research, Vol. 65 (2009), pp. 1087–1095.
cites as [2]: Sotirov P., Rangelov N., Ganchev O., Georgiev Tzv., Milev J., Petkov Z., “Influence of haunching”, in: Moment Resistant Connections of Steel Frames in Seismic Areas, E & FN Spon, 2000 [Chapter 3.3].
18. Sang Whan Han, Ki-Hoon Moon, Seong-Hoon Hwang, Božidar Stojadinović, “Rotation capacities of reduced beam section with bolted web (RBS-B) connections”, Journal of Constructional Steel Research, Vol. 70 (2012), pp. 256–263.
cites as [3]: Sotirov P., Rangelov N., Ganchev O., Georgiev Tzv., Milev J., Petkov Z., “Influence of haunching”, in: Moment Resistant Connections of Steel Frames in Seismic Areas, E & FN Spon, 2000 [Chapter 3.3].
19. Umair S.M., Hisham Q., Siddiqi Z.A., “Optimum Unbraced Length Ratios of Slender Steel Sections”, IACSIT International Journal of Engineering and Technology, vol. 5 (2013) No. 4, pp. 493-497.
cites as [2]: N. Rangelov, “On the effective stiffness of slender steel sections for deflection calculations”, Thin-Walled Structures, vol. 25, no. 3, pp.171-183, 1996.
20. Radoslavov G., „Study on steel tapered members“, PhD Thesis, UACEG, Sofia, 2015 (in Bulgarian).
cites as [19] Rangelov N., “Application of efficient design solutions with steel structures for industrial buildings”, Proceedings of the International Conference UACEG 2009: Science & Practice, Sofia, 29-31 October 2009.
21. Radoslavov G., „Study on steel tapered members“, PhD Thesis, UACEG, Sofia, 2015 (in Bulgarian).
cites as [20]: Rangelov N., “Effect of initial imperfections (residual stresses and out-of-flatness) on the local behaviour and resistance of welded I-girders with slender webs”, Annuaire de l’Université d’Architecture, de Génie Civil et de Géodesie, Sofia, vol. XXXIX (1998), fasc. VII, Sofia, pp. 103-114.
22. Draganov N., „Eurocode 3: БДС EN 1993-1-1: Design of Steel Structures of Buildings: Commentary, Examples, Recommendations“, Monograph, Sofia, 2016,
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23. Georgiev T., Comparison of both types of lateral-torsional buckling curves for steel members of constant cross-section subjected to bending, Mechanics, Transport, Communications, vol. 14, No. 2, 2016,
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24. Jose Henriques, Herve Degée, INNOSEIS – Valorization of innovative anti-seismic devices, Work Package 4 – Deliverable 4.1: Volume on case studies for low-rise buildings, 2017, www.innoseis.ntua.gr,
cites as [6] Georgiev Tzv., Zhelev D., Raycheva L., Rangelov N.,”INNOSEIS – Valorization of innovative anti-seismic devices”, Work Package 1 – Deliverable 1.1, Volume with information brochures for 12 innovative devices in English, European Commission Research Programme of the Research Fund for Coal and Steel, 2017.
25. Tsvetkov St., Design of steel arched roofs and realization the connection of „steel-concrete (R.C.)“ at bases, IXth International scientific conference оn architecture and civil engineering ArCivE 2019, 31 May – 02 June 2019, Varna, Bulgaria.
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26. Georgiev T., Students’ guide on steel structures, Sofia, 2020.
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27. Georgiev T., Students’ guide on steel structures, Sofia, 2020.
cites as [39] Braham M., Rangelov N., “Lateral-torsional buckling of steel I-section beams – some comments on the Eurocode 3 approach”, Stroitelstvo, No 1/2001, pp. 2-9.
28. Georgiev T., Students’ guide on steel structures, Sofia, 2020.
cites as [50] Vassilev M., N. Rangelov, „Stability problems of single storey steel frames (Part 1)", Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 51 (2018) 4.
29. Georgiev T., Students’ guide on steel structures, Sofia, 2020.
cites as [51] Vassilev M., N. Rangelov, „Stability problems of single storey steel frames – application of general method and GMNIA (Part 2)", Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 51 (2018) 4.
30. Georgiev T., Students’ guide on steel structures, Sofia, 2020.
cites as [52] Vassilev M., N. Rangelov, "Experimental study on the out-of-plane stability of steel portal frames", Proceedings of XVIII Anniversary International Scientific Conference "Construction and Architecture" VSU'2018, Sofia, Oct. 2018.
31. Georgiev T., Evolution of roof and wall claddings of steel structures, XX International Scientific Conference "Construction and Architecture" VSU'2020, Sofia, Oct. 2020.
cites Rangelov N., „Steel structures of thin-gauged cold-formed members. Theoretical backgrounds and design according to BDS EN 1993-1-3 and BDS EN 1993-1-5”, KIIP Sofia, 2015, ISBN: 978-619-90034-0-4.
32. Georgiev T., P. Baleva-Josifova, Design of roof and wall panels through “load” tables, Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 54 (2021) 3, 625-640.
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33. Georgiev T., P. Baleva-Josifova, Design of roof and wall panels through “load” tables, Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 54 (2021) 3, 625-640.
cites as [18] Rangelov N., Vasilev M., „Stability of purlins under wind suction“, Annual of the University of Architecture, Civil Engineering and Geodesy, vol. XLVI (2014), fasc. XI, Sofia, 2015, pp. 141-152.
34. Georgiev T., A revision of the detailing aspects of the steel roof trusses with a view to the 10 years’ experience of implementation of the Eurocodes in Bulgaria – Part 1, Proceedings of XXIII International Scientific Conference "Construction and Architecture" VSU'2023, vol. 54 (2023) 3, pp. 625-640
cites as [13] Rangelov N., Vasilev M., „Stability of purlins under wind suction“, Annual of the University of Architecture, Civil Engineering and Geodesy, vol. XLVI (2014), fasc. XI, Sofia, 2015, pp. 141-152.
35. Georgiev T., A revision of the detailing aspects of the steel roof trusses with a view to the 10 years’ experience of implementation of the Eurocodes in Bulgaria – Part 1, Proceedings of XXIII International Scientific Conference "Construction and Architecture" VSU'2023, vol. 54 (2023) 3, pp. 625-640
cites as [14] Rangelov N., „Steel structures of thin-gauged cold-formed members. Theoretical backgrounds and design according to BDS EN 1993-1-3 and BDS EN 1993-1-5”, KIIP Sofia, 2015, ISBN: 978-619-90034-0-4.
36. Georgiev T., A revision of the detailing aspects of the steel roof trusses with a view to the 10 years’ experience of implementation of the Eurocodes in Bulgaria – Part 1, Proceedings of XXIII International Scientific Conference "Construction and Architecture" VSU'2023, vol. 54 (2023) 3, pp. 625-640
cites as [27] Raykov St., N. Rangelov, D. Dinev, “Behaviour of tall chimneys with steel supporting structure under wind action. Part 1: The problem”, Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 54 (2021) 3, 537-552.
37. Georgiev T., A revision of the detailing aspects of the steel roof trusses with a view to the 10 years’ experience of implementation of the Eurocodes in Bulgaria – Part 1, Proceedings of XXIII International Scientific Conference "Construction and Architecture" VSU'2023, vol. 54 (2023) 3, pp. 625-640
cites as [28] Raykov St., N. Rangelov, D. Dinev, “Behaviour of tall chimneys with steel supporting structure under wind action. Part 2: The solution”, Annual of the University of Architecture, Civil Engineering and Geodesy, Vol. 54 (2021) 3, 553-562.
38. Gawande G.S., Gupta L.M., Classification of Open Web Steel Beam: An Analytical and Experimental Study, International Journal of Steel Structures, 2023
cites Vayas I., Rangelov N., “Classification of girders with I- or box cross-sections”, International Journal of Steel Structures, KSSC, Seoul, vol. 1 (2001) No.3, pp.153-165.

39. Masungi P.M. , Garlock M. E.M. , Quiel S.E. , Out-of-flatness of steel plate girder webs, Part I: Tolerance review and measurements, Journal of Constructional Steel Research, vol. 215, Apr. 2024
cites Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), pp. 151-156.
40. Masungi P.M. , Garlock M. E.M. , Augustyn K.E., Quiel S.E. , Out-of-flatness of steel plate girder webs, Part II: Shear strength and behaviour, Journal of Constructional Steel Research, vol. 219, Aug. 2024
cites Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), pp. 151-156.
41. Masungi P.M. , Effects of Out-of-Plane Patterns on Thin Steel Webs: Fabrication Imperfections and Low-Frequency Sinusoids, PhD Dissertation, Dept. of Civil and Environmental Engineering, Princeton University, May 2024
cites Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), pp. 151-156.
42. Ahdab D.M. , Redefining the Shear Capacity of Steel Plate Girders Based on Recent Shear Mechanics and an Extensive Numerical Investigation, PhD Dissertation, Dept. of Civil and Environmental Engineering, Princeton University, May 2024
cites as [27]: Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), pp. 151-156.

39. Masungi P.M. , Garlock M. E.M. , Quiel S.E. , Out-of-flatness of steel plate girder webs, Part I: Tolerance review and measurements, Journal of Constructional Steel Research, vol. 215, Apr. 2024
cites Rangelov N., “A Theoretical approach to the limiting of initial imperfections in steel plates”, Stahlbau 61 (1992), pp. 151-156.