• Steel and Composite Structures
• /
• v.6 no.5
• /
• pp.387-400
• /
• 2006

This paper discusses the composite mechanism and its effect upon the behavior of a steel reinforced concrete (SRC) member subjected to a flexural load. The relationship between member strength and deformation is established using the bond strength between the steel and reinforced concrete. An analytical model is proposed and used to incorporate the sectional strains and bond strength at the elastic and inelastic stages for moment-curvature relationship derivation. The results from the flexural load tests are used to validate the accuracy of the proposed model. Comparisons between the experimental information and the analytical results demonstrate close moment-curvature relevance, which justifies the applicability of the proposed method.

• Structural Engineering and Mechanics
• /
• v.54 no.4
• /
• pp.809-827
• /
• 2015

In this paper, seismic energy response of inelastic steel structures under earthquake excitations is investigated. For this purpose, a numerical procedure based on nonlinear dynamic analysis is developed by considering material, geometric and connection nonlinearities. Material nonlinearity is modeled by the inversion of Ramberg-Osgood equation. Nonlinearity caused by the interaction between the axial force and bending moment is also defined considering stability functions, while the geometric nonlinearity caused by axial forces is described using geometric stiffness matrix. Cyclic behaviour of steel connections is taken into account by employing independent hardening model. Dynamic equation of motion is solved by Newmark's constant acceleration method in the time history domain. Energy response analysis of space frames is performed by using this proposed numerical method. Finally, for the first time, the distribution of the different energy types versus time at the duration of the earthquake ground motion is obtained where in addition error analysis for the numerical solutions is carried out and plotted depending on the relative error calculated as a function of energy balance versus time.

• Steel and Composite Structures
• /
• v.17 no.2
• /
• pp.185-198
• /
• 2014

Carbon-manganese steel A42 (French standards) is used in steam generator pipes of nuclear center and subject to low cycle fatigue (LCF) loads. In order to obtain the material LCF behavior, the tests are implemented in a hydraulic fatigue machine. The LCF plastic deformation and cyclic stress in macroscope have been influenced by the accumulated low cycle fatigue damage. The constitutive kinematic and isotropic hardening modeling is modified with coupling fatigue damage to describe the fatigue behavior. The improved model seems to be good agreement with the test results.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.11
• /
• pp.996-1002
• /
• 2013

Conditions of stiffness for a steel spring torsional vibration damper are difficult and ambiguous. Nevertheless correct estimation of stiffness is essential and important in the damper design for the damper to activate properly in the field. In this paper, to build up the estimation method of steel spring torsional vibration damper a miniaturized model was developed for modelling between a spring and inner star of the damper. The method obtained from the results through the experiment and analysis of it was applied to the prototype torsional damper.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2006.03a
• /
• pp.249-258
• /
• 2006

In this paper, deformation capacity of steel moment connections with RHS column was investigated. Initially, non-linear finite element analysis of five bate steel beam models was conducted. The models were designed to have different detail at their beam-to-column connection, so that the flexural moment capacity was different respectively. Analysis results showed 4hat the moment transfer efficiency of the analytical model with RHS-column was poor when comparing to model with WF(Wide flnage)-column due to out-of-plane deformation of the RHS-column flange. The presence of scallop and thin plate of RHS column was also a reason of the decrease of moment transfer efficiency, which would result in a potential fracture of tile steel beam-to-column connections. Further test on beam-to-column connections with RHS column revealed that the moment transfer efficiency of a beam web decreased due to the out-of-plane deformation of column flange, which led to premature failure of the connection.

• Steel and Composite Structures
• /
• v.47 no.1
• /
• pp.121-134
• /
• 2023

This paper tested 11 concrete-encased concrete-filled steel tube (CFST) composite columns and one reinforced concrete column under combined axial compression and lateral loads. The primary parameters, including the loading system, axial compression ratio, volume stirrup ratio, diameter-to-thickness ratio of the steel tube, and stirrup form, were varied. The influence of the parameters on the failure mode, strength, ductility, energy dissipation, strength degradation, and damage evolution of the composite columns were revealed. Moreover, a two-parameter nonlinear seismic damage model for composite columns was established, which can reflect the degree and development process of the seismic damage. In addition, the relationships among the inter-story drift ratio, damage index and seismic performance level of composite columns were established to provide a theoretical basis for seismic performance design and damage assessments.

• Steel and Composite Structures
• /
• v.47 no.1
• /
• pp.135-145
• /
• 2023

This study presents a numerical investigation into the hysteretic behavior of cold-formed austenitic stainless steel square hollow section (SHS) brace members using a commercial finite element (FE) analysis software ABAQUS/Standard. The initial/post buckling and fracture life of SHS brace members are comprehensively investigated through parametric studies with FE models incorporating ductile fracture model, which is validated against the existing laboratory test results collected from the literature. It is found that the current predictive models are applicable for the initial buckling strengths of SHS brace members under cyclic loading, while result in significant inaccuracy in predictions for the post-buckling strength and fracture life. The modified predictive model is therefore proposed and the applicability was then confirmed through excellent comparisons with test results for cold-formed austenitic stainless SHS brace members.

• Computers and Concrete
• /
• v.33 no.6
• /
• pp.739-754
• /
• 2024

This study presents an innovative AI-driven approach to assess the ultimate axial load in Double-Skinned Profiled Steel sheet Composite Walls (DPSCWs). Utilizing a dataset of 80 entries, seven input parameters were employed, and various AI techniques, including Linear Regression, Polynomial Regression, Support Vector Regression, Decision Tree Regression, Decision Tree with AdaBoost Regression, Random Forest Regression, Gradient Boost Regression Tree, Elastic Net Regression, Ridge Regression, and LASSO Regression, were evaluated. Decision Tree Regression and Random Forest Regression emerged as the most accurate models. The top three performing models were integrated into a hybrid approach, excelling in accurately estimating DPSCWs' ultimate axial load. This adaptable hybrid model outperforms traditional methods, reducing errors in complex scenarios. The validated Artificial Neural Network (ANN) model showcases less than 1% error, enhancing reliability. Correlation analysis highlights robust predictions, emphasizing the importance of steel sheet thickness. The study contributes insights for predicting DPSCW strength in civil engineering, suggesting optimization and database expansion. The research advances precise load capacity estimation, empowering engineers to enhance construction safety and explore further machine learning applications in structural engineering.

• Steel and Composite Structures
• /
• v.14 no.3
• /
• pp.243-265
• /
• 2013

Distortional and local buckling are important factors that influences the bearing capacity of steel-concrete composite box-beam. Through theoretical analysis of distortional buckling forms, a stability analysis calculation model of composite box beam considering rotation of steel beam top flange is presented. The critical bending moment calculation formula of distortional buckling is established. In addition, mechanical behaviors of a steel beam web in the negative moment zone subjected separately to bending stress, shear stress and combined stress are investigated. Elastic buckling factors of steel web under different stress conditions are calculated. On the basis of local buckling analysis results, a limiting value for height-to thickness ratio of a steel web in the elastic stage is proposed. Numerical examples are presented to verify the proposed models.

• Journal of Welding and Joining
• /
• v.8 no.2
• /
• pp.70-79
• /
• 1990

Stainless clad steels were made through hot rolling process. Backing plates employed in this study were HSLA steel and mild steel. The shear bond strength increased with an increase of the soaking temperature and time. It was also found that the shear bond strength increased with an increase of the reduction ratio. The threshold deformation was observed to be 20% and 10% respectively when the soaking conditions of 15 min. at 900.deg. C and 30 min. at 1000.deg. C were applied. Either the rolling or the transverse direction did not give any significant difference in the shear bond strength. Stainless steel-HSLA steel was superior to stainless steel-mild steel in the same range of magnitude. Because the above experimental results were in contrary to the existing mechanisms, the new model was proposed to describe the bonding mechanism and the void formation.