Basic parameters test and <scp>3D</scp> modeling of bond between high‐strength concrete and ribbed steel bar after elevated temperatures

Zhao, Wei; Zhu, Bin

doi:10.1002/suco.201600005

“…Since different surfaces with various roughness are in contact at the actual condition of the rebar-concrete interface, it is too complicated to consider all frictional coefficients during slip in the numerical modelling. Based on previous experimental investigations ( [73] and [72]), the friction coefficient varies from 0.52 to 1.4. As shown in section 4.1.3.4 (Figure 4-20), comparing numerical results of the proposed technique and experimental results showed that considering the coefficient of friction μ=1 leads to the best results under different values of external pressure.…”

Section: External Pressure Effects On Local Bond-slip Behaviourmentioning

confidence: 99%

Numerical Study on Bar Slip Effects in Reinforced Concrete Bridge Bents Under Cyclic Loading

Rezaei Balouchi

2024

Preprint

0

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Assessing the bridge behaviour against cyclic loading after some powerful earthquakes, i.e., 1995 in Kobe, 2010 in Maule, showed thatbridge structures shouldbe designed andconstructed withgood detailing. Technical investigations showed that old bridge bents, i.e., that were designed prior 1980s in North America, are not equipped with appropriate detailing, especially in the beam-column joint. The most important factor in maintaining the composite application of reinforced concrete elements is the bond between rebars and surrounding concrete. Rebar slips and bond deterioration in cap beam-column joints in bridge bents, play a significant role on the cyclic behaviour under seismic loads. Previous studies on bridge bents indicated that in old bridge bents, damages initiate in the joint area, as a result of insufficient anchorage length of column longitudinal bars and lack of transverse reinforcement around them. Many researchers proposed different retrofitting schemes, such as applying transverse pressure on the joint area. However, to rehabilitate structures, first their as-built behaviour must be assessed. The common approach in assessing responses of older structures (used in present study) is collecting design details of structures, then develop a numerical model to simulate the experimental models, and real scale structures. The purpose of this research study is to propose a method in macro modelling to simulate the cyclic behaviour of older bridge bents with joint detailing deficiencies. Moreover, the effect of joint rehabilitation by applying external pressure on joints is investigated. In this case a fibre element, named slip simulator element, is developed in Opensees software. This model will be calibrated with experimental results on ordinary 2-span highway bridge bents which carried out by other researchers. To achieve an accurate macro modelling in Opensees, the input specifications of the macro model is attained from a micro model developed in ABAQUS. Comparing analytical results of macro modelling with experimental evidence shows that generally the proposed analytical approach is effective in predicting the cyclic response of both existing and rehabilitated bridge bents. Moreover, the proposed micro numerical modelling to determine inputs for the macro model is a reliable approach and has a good agreement with experimental results.

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“…Since different surfaces with various roughness are in contact at the actual condition of the rebar-concrete interface, it is too complicated to consider all frictional coefficients during slip in the numerical modelling. Based on previous experimental investigations ( [73] and [72]), the friction coefficient varies from 0.52 to 1.4. As shown in section 4.1.3.4 (Figure 4-20), comparing numerical results of the proposed technique and experimental results showed that considering the coefficient of friction μ=1 leads to the best results under different values of external pressure.…”

Section: External Pressure Effects On Local Bond-slip Behaviourmentioning

confidence: 99%

Numerical Study on Bar Slip Effects in Reinforced Concrete Bridge Bents Under Cyclic Loading

Rezaei Balouchi

2024

Preprint

0

View full text Add to dashboard Cite

Assessing the bridge behaviour against cyclic loading after some powerful earthquakes, i.e., 1995 in Kobe, 2010 in Maule, showed thatbridge structures shouldbe designed andconstructed withgood detailing. Technical investigations showed that old bridge bents, i.e., that were designed prior 1980s in North America, are not equipped with appropriate detailing, especially in the beam-column joint. The most important factor in maintaining the composite application of reinforced concrete elements is the bond between rebars and surrounding concrete. Rebar slips and bond deterioration in cap beam-column joints in bridge bents, play a significant role on the cyclic behaviour under seismic loads. Previous studies on bridge bents indicated that in old bridge bents, damages initiate in the joint area, as a result of insufficient anchorage length of column longitudinal bars and lack of transverse reinforcement around them. Many researchers proposed different retrofitting schemes, such as applying transverse pressure on the joint area. However, to rehabilitate structures, first their as-built behaviour must be assessed. The common approach in assessing responses of older structures (used in present study) is collecting design details of structures, then develop a numerical model to simulate the experimental models, and real scale structures. The purpose of this research study is to propose a method in macro modelling to simulate the cyclic behaviour of older bridge bents with joint detailing deficiencies. Moreover, the effect of joint rehabilitation by applying external pressure on joints is investigated. In this case a fibre element, named slip simulator element, is developed in Opensees software. This model will be calibrated with experimental results on ordinary 2-span highway bridge bents which carried out by other researchers. To achieve an accurate macro modelling in Opensees, the input specifications of the macro model is attained from a micro model developed in ABAQUS. Comparing analytical results of macro modelling with experimental evidence shows that generally the proposed analytical approach is effective in predicting the cyclic response of both existing and rehabilitated bridge bents. Moreover, the proposed micro numerical modelling to determine inputs for the macro model is a reliable approach and has a good agreement with experimental results.

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“…Nowadays RC reinforcing bars are produced with a special thermal treatment process usually called Tempcore . It is based on a controlled, three‐stage cooling of a bar just after it leaves the last stand of hot‐rolling mill.…”

Section: Introductionmentioning

confidence: 99%

“…Experiments, which can be useful for assessment of structures after fire, are also present in the literature . describe tests of residual yield strength of bars that were heated to a high temperature and allowed to slowly cool down in air . examined the reduction of bond strength between concrete and steel as the result of high temperature .…”

Section: Introductionmentioning

confidence: 99%

Experimental approach to strength reduction and elongation of self‐tempered reinforcing bars tensioned at a steady and an increasing temperature

Kowalski

¹

,

Kisieliński

²

2018

Structural Concrete

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This paper describes experiments performed on specimens of reinforcing bars 10, 12, and 16 mm in diameter. The bars were made of 500 MPa steel produced with Tempcore technology and were subject to simultaneous action of high temperature and tension. The experiments were performed both at a constant temperature of 100, 200, 300, 400, 500, and 600°C and in an increasing temperature and constant load corresponding to 0, 30, 45, 60, or 75% of steel yield strength at a room temperature. The analysis of the obtained results is focused on the reduction of steel strength and on the bar elongation due to high temperature. In the former case, different failure criteria were considered, which corresponded to the elongation of 0.2%, the elongation of 2% or the bar failure. The experimental results were compared with Eurocode 1992‐1‐2 models for the bar elongation below and over 2% and against results of similar test reported in the literature. In the study of bar elongation, different components of total elongation, which can be measured during a constant and an increasing temperature test, are described and compared with each other and Eurocode 1992‐1‐2 model.

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Basic parameters test and 3D modeling of bond between high‐strength concrete and ribbed steel bar after elevated temperatures

Cited by 17 publications

References 35 publications

Numerical Study on Bar Slip Effects in Reinforced Concrete Bridge Bents Under Cyclic Loading

Numerical Study on Bar Slip Effects in Reinforced Concrete Bridge Bents Under Cyclic Loading

Numerical Study on Bar Slip Effects in Reinforced Concrete Bridge Bents Under Cyclic Loading

Experimental approach to strength reduction and elongation of self‐tempered reinforcing bars tensioned at a steady and an increasing temperature

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