Deformation calculation of space reinforced concrete frame by FEM with allowance for vibrocreep of concrete
DOI:
https://doi.org/10.32347/2410-2547.2019.103.219-234Keywords:
space frame, stiffness matrix, finite element method, algorithm, shrinkage, creep, concrete vibrocreepAbstract
The efficiency of the reinforced frameworks depends to a large extent on a properly framing scheme. If the framing scheme is made of reinforced concrete, the frame displays at various long static and dynamic loads such a characteristic phenomenon as the creep and vibrocreep of concrete. In addition, the space frame must take into account the buckling strain. An algorithm for the calculation of n-times kinematicly indeterminate space reinforced concrete frames has been developed, taking into account buckling strain, creep and vibrocreep based on finite element analysis and recursion formulas, which makes it possible to simplify the calculation of bar systems for long processes. Recursion formulas can be used to develop programs for calculating space frames. The article presents the research and obtained a stiffness matrix of three types of reinforced concrete space finite element, taking into account buckling strain and long processes. An algorithm for calculating reinforced concrete bar systems was developed taking into account the space work, buckling strain, vibocreep of concrete by finite element method. An executed example of the calculation of a reinforced concrete space framed structure showed that taking into account the buckling strain of the rods and the vibrocreep of concrete significantly alter the stress-strain state of space systems. Some frame motions increase by 135-348% over time, and the force variation varies from + 88% to -231% in comparison with elastic non-deformation values. The increase in displacements is mainly influenced by creep and vibration creep, which account for 135% –184% and 228% - 338%, respectively, and for the growth of efforts – buckling strain, the share of which ranged from + 10% to -228%. Deformation calculations of framed reinforced concrete systems should be performed not only to establish a change in the pattern of internal forces and time motions, but in the most dangerous places of the system to determine the stresses in reinforced and concrete and deflections to prevent the excess of calculated resistances of materials and normative motions.
References
Weinberg, D.V., Chudnovsky, V.G. Calculation of space frames (Raschet prostranstvennykh ram). - K .: Gosstroyizdat USSR, 1964. – 308 p.
Drozdov P.F. Design and calculation of load-bearing systems of multistoried buildings and their elements (Konstruirovaniye i raschet nesushchikh sistem mnogoetazhnykh zdaniy i ikh elementov). - M .: Stroiizdat, 1977. - 223 p.
Nemchinov Yu.I. Calculation of space structures (finite element method) (Raschet prostranstvennykh konstruktsiy (metod konechnykh elementov)). - K.: Budivelnyk, 1980. - 232 p.
Bazhenov V.A., Sakharov A.S., Melnichenko G.I. The finite element method in problems of structural mechanics (Metod konechnykh elementov v zadachakh stroitel'noy mekhaniki). - K.: KGTUSA, 1994.- 368 p.
Varvak P.M., Buzun I.M., Gorodetsky A.S. The finite element method (Metod konechnykh elementov). - K .: Vishcha school, 1981. - 176 p.
Maslennikov A.M. Calculation of engineering structures by the finite element method (Raschet stroitel'nykh konstruktsiy metodom konechnykh elementov). - L .: LISI, 1977. - 80 p.
Isakhanov G.V., Granat S.Ya., Melnichenko G.I. Structural mechanic: Calculation of core systems on a computer (Stroitel'naya mekhanika: Raschet sterzhnevykh sistem na EVM). - K .: Vishcha school, 1990. - 229 p.
Prokopovich I.E., Yaremenko A.F. Application of the finite element method to solving problems of the linear theory of creep (Primeneniye metoda konechnykh elementov k resheniyu zadach lineynoy teorii polzuchesti) // Stroit. mekh. i raschet sooruzheniy, № 6, 1982. - pp. 29-33.
Yevzerov I.D. Finite element method for long-term load effects (Metod konechnykh elementov pri raschete na dlitel'noye deystviye nagruzki) // Resistance of materials and theory of structures, vol. 56. - K .: Budivelnik, 1990. -P. 98-103.
Kubaneshivili A.S., Menagarishvili Z.R., Tushishvili Z.I. Application of FEM to the calculation of reinforced concrete structures taking into account creep of concrete (Primeneniye MKE k raschetu ZHBK s uchetom polzuchesti betona) // Beton i zhb. v energ. str-ve. Mater. Vsesoyuz. konf. po bet. i zhb. Kazan', okt.,1988. - Tbilisi, 1988. - pp. 94-98.
Yatsenko E.A., Kornilov S.V., Bovin A.A. Theory of creep of reinforced concrete structures (Teoriya polzuchesti zhelezobetonnykh konstruktsiy). - Dnepropetrovsk: Guadeamus, 2000. - 600 p.
Kolev P. Research stability of a rod in creep conditions using FEM in a generalized form (Issledovaniye ustoychivosti sterzhnya v usloviyakh polzuchesti s pomoshch'yu MKE v obobshchennom vide) // Construction, vol. 35, No. 1, 1988. - p. 16-18.
Belkin V.P., Kaledin V.O. Application of finite elemental models to the problem of creep stability (O primenenii konechno elementnykh modeley k zadache ustoychivosti pri polzuchesti) // Sib. metallurg. inst. - Novokuznetsk, 1988. - 5 s. Dep. v VINITI 16.11.88, № 8144-V88.
Yatsenko E.A., Slobodianyuk S.A. The theory of long-term strength and stability of rod-reinforced concrete systems with allowance for creep of concrete. Monograph. (Teoriya dlitel'noy prochnosti i ustoychivosti sterzhnevykh zhelezobetonnykh sistem s uchetom polzuchesti betona) - Dnepropetrovsk: PDABA; Porogi, 2002. – 252 p.
Slobodianyuk S.A. Deformation calculation and stability of core concrete systems with allowance for long-term processes (Deformatsionnyy raschet i ustoychivost' sterzhnevykh zhelezobetonnykh sistem s uchetom dlitel'nykh protsessov) // Diss. ... doctor tech. sciences: 05.23.01. - Dnepropetrovsk: PGASA, 2002. - 280 p.
Slobodyanyuk S.A., Buratinskiy A.P., Shcherbachov A.D. The theory of long durability and stability of core reinforced concrete systems with allowance for the creep and vibrocreep of concrete. Reports of research work on the state theme № 32 (state registration number 0110U002434, scientific supervisor, doctor of technical sciences, professor S.A. Slobodianyuk) (Teoriya tryvaloyi mitsnosti ta stiykosti sterzhnevykh zalizobetonnykh system z urakhuvannyam povzuchosti ta vibropovzuchosti betonu. Zvity NDR po derzhavniy temi № 32)
Slobodyanyuk S.A., Buratinskiy A.P. The method of initial parameters of vibrocreep concrete (Metod nachal'nykh parametrov vibropolzuchesti beton) // Beton i zhelezobeton v Ukraine. - 2010. - № 5. - p. 6 - 7.
Bolshakov V.I., Yatsenko E.A., Sossa G. Fundamentals of the finite element method (Osnovy metoda konechnykh elementov). - Dnepropetrovsk: Gaudeamus, 2000. - 255 p.
Yatsenko E.A. Methods for calculating reinforced concrete structures for a long-term effect, taking into account concrete creep (Metody rascheta zhelezobetonnykh konstruktsiy na dlitel'noye vozdeystviye s uchetom polzuchesti betona): Diss. ... doctor tech. sciences: 05.23.01.- M., 1989. - 364 p.
DBN V.2.6-98: 2009. Concrete and reinforced concrete constructions. General considerations (Betonni ta zalizobetonni konstruktsiyi. Osnovni polozhennya). - K.: Minregionstroy of Ukraine, 2011. - 71 p.
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