Ananthalakshmi K. Iyer¹, A. Rama Chra Murthy², Smitha Gopinath², Nagesh R. Iyer³

CMC-Computers, Materials & Continua, Vol.42, No.3, pp. 227-244, 2014, DOI:10.3970/cmc.2014.042.227

Abstract A non-linear fracture mechanics based approach is proposed to depict a typical fracture mechanism from initiation to growth, eventually leading to failure. This concept is developed for a lightly reinforced beam in flexure. The proposed model integrates the existing methodology of a Stress Intensity Factor equilibrium equation with the bridging forces developed in concrete cover and rebar. The model and solution algorithm outlined presents an elaborate understanding of the mechanism involved and is significant in predicting the behaviour of flexural members. The analysis is performed using MATLAB programming. The proposed approach ensures a maximum tolerable More >

Yuvaraj P¹, A Ramachra Murthy², Nagesh R Iyer³, S.K. Sekar⁴, Pijush Samui⁵

CMC-Computers, Materials & Continua, Vol.41, No.3, pp. 193-214, 2014, DOI:10.3970/cmc.2014.041.193

Abstract This paper presents fracture mechanics based Artificial Neural Network (ANN) model to predict the fracture characteristics of high strength and ultra high strength concrete beams. Fracture characteristics include fracture energy (Gf), critical stress intensity factor (KIC) and critical crack tip opening displacement (CTODc). Failure load of the beam (Pmax) is also predicated by using ANN model. Characterization of mix and testing of beams of high strength and ultra strength concrete have been described. Methodologies for evaluation of fracture energy, critical stress intensity factor and critical crack tip opening displacement have been outlined. Back-propagation training technique… More >

X.P. Shen^1,2, X.C. Wang¹

CMC-Computers, Materials & Continua, Vol.39, No.2, pp. 135-152, 2014, DOI:10.3970/cmc.2014.039.135

Abstract Emphases of this study were placed on the modelling of plastic damage behaviour of prestressed structural concrete, with special attention being paid to the stress-triaxiality dependent plastic hardening law and the corresponding damage evolution law. A definition of stress triaxiality was proposed and introduced in the model presented here. Drucker-Prager -type plasticity was adopted in the formulation of the plastic damage constitutive equations. Numerical validations were performed for the proposed plasticity-based damage model with a driver subroutine developed in this study. The predicted stress-strain behaviour seems reasonably accurate for the uniaxial tension and uniaxial compression More >

S. Liu¹, X. Liu^2,3, Y. Yuan², P. F. He¹, H. A. Mang^2,4

CMC-Computers, Materials & Continua, Vol.39, No.2, pp. 85-112, 2014, DOI:10.3970/cmc.2014.039.085

Abstract Autogenous shrinkage is defined as the bulk deformation of a closed, isothermal, cement-based material system, which is not subjected to external forces. It is associated with the hydration process of the cement paste. From the viewpoint of engineering practice, autogenous shrinkage deformations result in an increase of tensile stresses, which may lead to cracking of early-age concrete. Since concrete is a multi-phase composite with different material compositions and microscopic configurations at different scales, autogenous shrinkage does not only depend on the hydration of the cement paste, but also on the mechanical properties of the constituents… More >

A. Likhith Reddy¹, Shirleen Charles¹, C. Bharathi Priya², G.V. Rama Rao², N. Gopalakrishnan^3,4 , A. Rama Mohan Rao³

Structural Durability & Health Monitoring, Vol.9, No.4, pp. 325-347, 2013, DOI:10.32604/sdhm.2013.009.325

Abstract Details of the investigations on an unexplored application of Electro Mechanical Impedance (EMI) technique using smart piezoelectric (PZT) sensors for damage detection of concrete shear wall structures under crack opening and closing is presented in this paper. The behavior and the ability of this method to detect damages, in a heterogeneous quasi-brittle material is studied for its effective utilization in structural health monitoring. The paper discusses the experimental investigations conducted on a concrete shear wall using PZT patches. Conductance data is acquired at different applied lateral displacements of shear wall. Damage index is calculated using More >

Mehdi Mohammadpour Lima^1,2, Dane Miller¹, Jeung-Hwan Doh¹

Structural Durability & Health Monitoring, Vol.9, No.4, pp. 269-285, 2013, DOI:10.32604/sdhm.2013.009.269

Abstract Iran is located in a seismic prone region with several earthquakes occurring annually causing extensive damage to structures and infrastructure. Guilan province is located in the northern part of the country, exhibiting a large population, moderate climate and extensive river system. This region experiences high humidity, several active faults and high seismic hazard potential. This highlights the importance of an active and extensive maintenance and rehabilitation program for the bridges in this region. Structural Health Monitoring (SHM) is an engineering tool used to control changing conditions of infrastructure providing useful information for management, decision making… More >

Smitha Gopinath^1,2, A. Ramachandra Murthy¹, Nagesh R. Iyer¹

Structural Durability & Health Monitoring, Vol.9, No.1, pp. 1-20, 2013, DOI:10.32604/sdhm.2013.009.001

Abstract This paper deals with the performance of concrete specimens confined with different glass fabric reinforcement in organic binder consisting of resins. Three varieties of glass fabrics such as woven roving (WR), chopped strand mat (CSM), and textile reinforcement have been studied in the investigation. Experiments have been conducted on unconfined and confined concrete cylindrical specimens under compression. The effect of number of layers on confinement has been studied for specific cases. Specimens have been tested under displacement control. It is observed from the experiments that there is an increase in load carrying capacity as well More >

Smitha Gopinath^1,2, J. Rajasankar¹, Nagesh R.Iyer¹, A.Rama Chandra Murthy¹

CMC-Computers, Materials & Continua, Vol.33, No.1, pp. 87-110, 2013, DOI:10.3970/cmc.2013.033.087

Abstract An integrated model is proposed to describe tension stiffening in reinforced concrete (RC) flexural members that are undergoing uniform corrosion of reinforcement. The tension stiffening model is taken as base to incorporate the effects of reinforcement corrosion. The model is developed in two steps. In the first step, tension stiffening of concrete is modelled using an exponential stress-strain curve defined as function of a decay parameter. Modular ratio and reinforcement ratio are considered in the definition of the decay parameter. In the second step, the effects of uniform corrosion of reinforcement are integrated with the… More >

K. Luo¹, Y. L. Pi¹, W. Gao¹, M. A. Bradford¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.1, pp. 31-58, 2013, DOI:10.3970/cmes.2013.095.031

Abstract This paper presents a theoretical analysis for the time-dependent nonlinear behaviour and buckling of shallow concrete-filled steel tubular (CFST) arches under a sustained central concentrated load. The virtual work method is used to establish the differential equations of equilibrium for the time-dependent behaviour and buckling analyses of shallow CFST arches, and the age-adjusted effective modulus method is adopted to model the creep behaviour of the concrete core. Analytical solutions of time-dependent displacements and internal forces of shallow CFST arches are derived. It has been found that under a sustained central concentrated load, the deformations and… More >

S. Liu¹, X. Liu², X. F. Guan³, P.F. He¹, Y. Yuan²

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.2, pp. 173-191, 2013, DOI:10.3970/cmes.2013.092.173

Abstract Early performance of mass concrete structures is very sensitive to the thermal expansion characteristics of concrete. As a kind of multi-phase composite, concrete has different material composition and microscopic configuration in different scales. Its thermal expansion coefficient (CTE) depends not only on the physical and mechanical properties of the constituents, but also on their distribution. What’s more, CTE is also time-dependent with the procedure of hydration. This research proposes a stochastic multi-scale model for analyzing CTE of concrete. In the developed model, concrete macro-scale is divided into three different levels: cement paste scale, mortar scale… More >