Vol.8, No 2, 2010 pp. 265 - 275
UDC 624.01:624.042.8(045)=11
DOI: 10.2298/FUACE1002261I
STABILITY DESIGN OF STRUCTURES WITH SEMI-RIGID CONNECTIONS
Tomislav Igić, Slavko Zdravković, Dragan Zlatkov, Srđan Živković, Nikola Stojić
University of Niš, Faculty of Civil Engineering and Architecture, Serbia The Highway Institute, Belgrade, Serbia
The paper points out to the differences of the First order theory and Second order theory and of the significance in practical calculations. The paper presents theoretical foundations and expressions of calculations of impacts on the stability of structure, that is, review of the Second order theory in a bridge with members semi-rigid connections in joints. In the real structures in general and the especially in the prefabricated structures the connection of members in the nodes can be partially rigid which can be very significant for the changes in tension and deformation. If the influence of the normal forces is significant and the structure is slender then it is necessary to carry out a calculation according to the Second order theory because the balance between internal and external forces really established on the deformed configuration and displacements in strict formation are also unreal. The importance and significance of the calculations and distribution of impact according to the Second order theory were presented in numerical examples as well as the calculation of critical load as well as the buckling length of members with semi-rigid connections in joint.
Key words: semi-rigid joints, stability, critical load, buckling length.
PRORAČUN STABILNOSTI KONSTRUKCIJA SA POLUKRUTIM VEZAMA
U radu se ukazuje na razlike Teorije prvog i Teorije drugog reda kao i tom značaju u praktičnim proračunima. Daju se teorijske osnove i izrazi proračuna uticaja na stabilnost konstrukcija, tj pregled Teorije drugog reda kod mosta sa polukrutim vezama štapova u čvorovima. U realnim konstrukcijama uopšte, a posebno u montažnim, veze štapova u čvorovima mogu biti delimično krute, što može imati značajnog uticaja na promene natezanja i deformacije. Ukoliko je uticaj normalnih sila značajan a konstrukcije vitke onda je neminovno proračun sprovesti po Teoriji drugog reda jer se ravnoteže između unutrašnjih i spoljašnjih sila realno uspostavlja na deformisanoj konfiguraciji sistema te su uslovi ravnoteže nerealni. Veze između deformacije i pomeranja u strogoj formaciji su takođe nerealne. Na numeričkim primerima prikazan je uticaj i značaj proračuna i preraspodele uticaja po Teoriji drugog reda, tj. proračun kritičnog opterećenja kao i dužine izvijanja štapova sa polukrutim vezama štapova u švorovima.
Ključne reči: polukrute veze, stabilnost, kritično opterećenje, dužina izvijanja