Wyniki wyszukiwania - BazTech

1

O wpływie poziomu obciążenia i wzmocnienia naprężonymi taśmami CFRP na nośność i odkształcalność belek żelbetowych

Kotynia R., Lasek K., Staśkiewicz M.

Zeszyty Naukowe. Budownictwo / Politechnika Łódzka

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2011

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Z. 63

191-204

PL

Praca dotyczy wzmacniania żelbetowych belek na zginanie przy użyciu naprężonych taśm kompozytowych CFRP. Przedstawiono program i wyniki własnych badań doświadczalnych belek wzmacnianych pod obciążeniem. Przeprowadzono analizę wpływu poziomu obciążenia belek przed wzmocnieniem na ich nośność i odkształcalność.

EN

Paper describes experimental research of reinforced concrete beams strengthened for flexure with pretension CFRP laminates. Before strengthening beams were exhausted to 25% or 75% of load capacity of non-strengthened beam. Research showed high efficiency of strengthening with pretension strips. Strengthening ratio varied in the range from 1,9 to 2,2 of the non-strengthened beam. Flexural strengthening of RC beams with pretension CFRP strips is very effective both for ultimate limit state and serviceability limit state, especially in case of highly exhausted elements before strengthening. Using of the active strengthening system causes significant reduction of strains in concrete and mid-span deflections and increase in stiffness of tested elements.

2

Weryfikacja i modyfikacja modeli teoretycznych do wymiarowania elementów ściskanych wzmacnianych materiałami FRP

Kamiński M., Trapko T., Bywalski C.

Zeszyty Naukowe. Budownictwo / Politechnika Łódzka

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2006

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Z. 55

34-40

EN

Problem to design RC columns strengthened with CFRP composites has been presented in this paper. Two theoretical models of dimensioning has been described in this paper. On the basis of own test results has been proposed to expand and modify one of the models.

3

Modelowanie numeryczne elementów wzmocnionych nakładkami FRP

Górski M., Krzywoń R.

Zeszyty Naukowe. Budownictwo / Politechnika Łódzka

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2006

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Z. 55

18-24

EN

Performed numerical analyses confirmed observations obtained in laboratory tests concerning members behavior on every step of loading. Excellent sirnilarity was obtained for non-strengthened bearns, while model with CFRP strengthening behaved sirnilarly till achieving highest value of torque. Second phase of work differs from observed. Numerical model with CFRP strengthening demands further calibration in post -cracking phase, special efforts will be undertaken for development of pre-cracked member model. Properly verified numerical analyses may be treat as laboratory test completing. Computing allows diagnosing and estimating phenomena whose experimental prove can be very difficult, cost consurning or sometimes -impossible. It concerns in particular measurements demanding very sophisticated and expanded standfor complex state of stresses.

4

Komputerowa symulacja efektów wzmocnienia żelbetowych wzmocnionych na zginanie naprężonymi taśmami kompozytowymi FRP

Kotynia R., Bonikowski M.

Zeszyty Naukowe. Budownictwo / Politechnika Łódzka

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2006

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Z. 55

42-48

EN

The paper presents calculated analysis of several strengthening effects on the load bearing capacity and serviceability of the reinforced concrete structures strengthened with initially prestressed strips. The following main parameters have been considered in the analysis: steel reinforcement ratio, a type of the strip and level of FRP prestressing. A non-linear model of RC members strengthened with CFRP rnaterials has been used for analysis of strains and load bearing capacity. The model considers only normal stresses, a non-linear relationship for concrete in compression, experimental relationship for reinforcing steel and CFRP composites, the tension stiffening principle and the pIane section principle. By prestressing these strips, the effectiveness of the strengthening can be improved considerably. An optimal prestressing level is presented with a discussion of the ca1culated results.

5

Badania doświadczalne belek wzmocnionych na zginanie metodą NSMR

Kotynia R., Frymus K.

Zeszyty Naukowe. Budownictwo / Politechnika Łódzka

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2006

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Z. 55

50-64

EN

The paper focuses on the test results of RC be am s strengthened for flexure with NSM CFRP strips. The objective of this study was to obtain the same ultimate load for four beams with different steel and CFRP reinforcement ratios. bearns were differed in steel and CFRP reinforcement ratio. Results of the test indicated that the lower was steel reinforcement ratio and higher was CFRP ratio the lower was stiffness and ultimate load of strengthened beams. The reason of this situation was the axial stiffness EfAf of NSMR CFRP strips, which was lower than stiffness of the steel reinforcement.