عنوان مقاله [English]
Corrosion of steel reinforcement in concrete structures is one of the most influencing factors in the loss of durability of reinforced concrete (RC) structures. Neglecting the effects of corrosion has unpleasant consequences and may lead to the failure of structures before their designed life time. Corrosion reduces the cross section of the steel reinforcement, changes the mechanical properties of the steel, decreases the strength of the concrete, and ultimately reduces the capacity and ductility of RC structures. In this study, the effects of corrosion on the moment-curve diagram of structural elements are studied and then compared with the approaches recommended by guidelines such as FEMA-356. To evaluate the effect of steel corrosion on the performance of structures, two RC frames (3-storey and 7-storey) are modeled and two corrosion scenarios are applied to beams and columns of the structures. Then, capacity curves of structures as well as design parameters such as ductility coefficients are obtained by nonlinear static (pushover) analysis of the structures considering the effects of corrosion on moment-curvature diagrams of structural elements. The results show that the coefficient of awareness of 0.75 according to the guidelines such as FEMA-356 can lead to overestimate the structural capacity in highly corrosive environment. It also leads to conservative and uneconomic results in a low corrosive environment. It is observed that the capacities of the 3 and 7-storey structures have been decreased between 19 to 36 percent due to corrosion. Results also show that corrosion reduces the structural capacity between 8 to 28 percent.
Salari, M.R. and Spacone, E., )2001(. Finite element formulations of one-dimensional elements with bond-slip. Engineering structures, 23(7), pp.815-826.
Chen, G. and Baker, G., )2003(. Influence of bond slip on crack spacing in numerical modeling of reinforced concrete. Journal of Structural Engineering, 129(11), pp.1514-1521.
Böhni, H. ed., )2005(. Corrosion in reinforced concrete structures. Elsevier.
Broomfield, J.P., )2003(. Corrosion of steel in concrete: understanding, investigation and repair. CRC Press.
Luca, B., Bernhard, E., Pietro, P. and Rob, P., )2004(. Corrosion of steel in concrete: prevention, diagnosis, repair. Bedin: Wiley—VCH.
Malumbela, G., Alexander, M. and Moyo, P., )2009(. Steel corrosion on RC structures under sustained service loads-A critical review. Engineering Structures, 31(11), pp.2518-2525.
Shayanfar, M.A., Ghalehnovi, M. and Safiey, A., (2007). Corrosion effects on tension stiffening behavior of reinforced concrete. Computers and Concrete, 4(5), pp.403-424.
Simioni, P., (2009). Seismic response of reinforced concrete structures affected by reinforcement corrosion (Doctoral dissertation, Technische Universität Braunschweig).
Yalciner, H., Sensoy, S. and Eren, O., (2012). Time-dependent seismic performance assessment of a single-degree-of-freedom frame subject to corrosion. Engineering Failure Analysis, 19, pp.109-122.
Dizaj, E.A., Madandoust, R. and Kashani, M.M., (2018). Probabilistic seismic vulnerability analysis of corroded reinforced concrete frames including spatial variability of pitting corrosion. Soil Dynamics and Earthquake Engineering, 114, pp.97-112.
Kashani, M.M., Lowes, L.N., Crewe, A.J. and Alexander, N.A., (2015). Phenomenological hysteretic model for corroded reinforcing bars including inelastic buckling and low-cycle fatigue degradation. Computers & Structures, 156, pp.58-71.
Iran's Management and Planning Organization, (2014), Instruction for Seismic Rehabilitation of Existing Buildings (Journal 360), (in Persian).
Prestandard, F.E.M.A., (2000). commentary for the seismic rehabilitation of buildings (FEMA356). Washington, DC: Federal Emergency Management Agency, 7.
Shayanfar, M., Savoj, H.R., Ghanooni-Bagha, M. and Khodam, A., (2018). The effects of corrosion on seismic performance of reinforced concrete moment frames. Journal of Structural and Construction Engineering, 5, pp.146-59.
Lee, H.S. and Cho, Y.S., (2009). Evaluation of the mechanical properties of steel reinforcement embedded in concrete specimen as a function of the degree of reinforcement corrosion. International journal of fracture, 157(1-2), pp.81-88.
Rodriguez, J., Ortega, L.M. and Casal, J., (1994), June. Corrosion of reinforcing bars and service life of reinforced concrete structures: corrosion and bond deterioration. In International conference on concrete across borders, Odense, Denmark (Vol. 2, pp. 315-326).
Ghanooni-Bagha,M, Shayanfar M. A., Yekefallah M. R., The Effect of Changes in Carbon-dioxide Concentrations on Corrosion Initiation of Reinforced Concrete Structures, (2018), Amirkabir J. Civil Eng., 50(4), 697-706. (In Persian)
Shayanfar,M. Ghanooni-Bagha,M. (2016). practical Training in Building Retrofit Methods, Fadak Isatis (in Persian).
Ting, S.C. and Nowak, A.S., (1991). Effect of reinforcing steel area loss on flexural behavior of reinforced concrete beams. Structural Journal, 88(3), pp.309-314.
Haselton, C.B. and Pacific Earthquake Engineering Research Center, (2008). Beam-column element model calibrated for predicting flexural response leading to global collapse of RC frame buildings. Pacific Earthquake Engineering Research Center.
Ibarra, L.F., Medina, R.A. and Krawinkler, H., (2005). Hysteretic models that incorporate strength and stiffness deterioration. Earthquake engineering & structural dynamics, 34(12), pp.1489-1511.
Opensees. The open system for earthquake engineering simulation, (2012). Berkeley Pacific Earthquake Engineering Research Center, University of California.
Deierlein, G., Reinhorn, A. and Willford, M., (2010). NEHRP Seismic Design Technical Brief No. 4-Nonlinear Structural Analysis for Seismic Design: A Guide for Practicing Engineers (No. Grant/Contract Reports (NISTGCR)-10-917-5).
Berry, M.P., Lehman, D.E. and Lowes, L.N., (2008). Lumped-plasticity models for performance simulation of bridge columns. ACI Structural Journal, 105(3), p.270.
Panagiotakos, T.B. and Fardis, M.N., (2001). Deformations of reinforced concrete members at yielding and ultimate. Structural Journal, 98(2), pp.135-148.
Structural Engineering Institute., (2006). Minimum design loads for buildings and other structures. Amer Society of Civil Engineers.
ACI Committee and International Organization for Standardization, (2008). Building code requirements for structural concrete (ACI 318-08) and commentary. American Concrete Institute.
Hosseinpour, F. and Abdelnaby, A.E., 2017. Effect of different aspects of multiple earthquakes on the nonlinear behavior of RC structures. Soil Dynamics and Earthquake Engineering, 92, pp.706-725.
Applied Technology Council, (2009). Quantification of building seismic performance factors. US Department of Homeland Security, FEMA.