• Earthquakes and Structures
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• v.22 no.5
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• pp.475-485
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• 2022

This paper presents a comparative experimental study on structural behavior of the interlocking masonry walls under in-plane cyclic loading. The main purpose of this study is to increase lateral load-bearing capacities of masonry walls by using interlocking units. The interlocking units were designed by considering failure modes of masonry walls and produced using lightweight foamed concrete. To this end, three masonry walls which are hollow, fully grouted, and reinforced were constructed with interlocking units. Also, a traditional masonry brick wall was built for comparison reasons. The walls were tested under in-plane cyclic loading. Then, structural parameters of the walls such as lateral load bearing and total energy dissipation capacities, ductility, stiffness degradation as well as failure modes obtained from the tests were compared with each other. The results have shown that the walls with the interlocking units have better structural performance than traditional masonry brick walls and they may be used in the construction of low-rise masonry structures in rural areas to improve in-plane structural performance.

• Structural Engineering and Mechanics
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• v.62 no.5
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• pp.643-649
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• 2017

Masonry walls are amongst the oldest building systems. A large portion of the research on these structures focuses on the load-bearing walls. Numerical methods have been generally used in modelling load-bearing walls during recent years. In this context, macro and micro modelling techniques emerge as widely accepted techniques. Micro modelling is used to investigate the local behaviour of load-bearing walls in detail whereas macro modelling is used to investigate the general behaviour of masonry buildings. The main objective of this study is to investigate the elastic behaviour of the load- bearing walls in masonry buildings by using micro modelling technique. In order to do this the brick and mortar units of the masonry walls are modelled by the combination of plane truss elements and plane frame elements with no shear deformations. The model used in this study has fewer unknowns then the models encountered in the references. In this study the vertical frame elements have equivalent elasticity modulus and moment of inertia which are calculated by the developed software. Under in-plane static loads the elastic displacements of the masonry walls, which are encountered in literature, are calculated by the developed software, where brick units are modelled by plane frame elements, horizontal joints are modelled by vertical frame elements and vertical joints are modelled by horizontal plane truss elements. The calculated results are compatible with those given in the references.

• Steel and Composite Structures
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• v.47 no.1
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• pp.37-50
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• 2023

This paper presented an investigation into steel tubes encased high-strength concrete (STHC) composite walls, wherein steel tubes were embedded at the boundary elements of high-strength concrete walls. A series of cyclic loading tests was conducted to evaluate the failure pattern, hysteresis characteristics, load-bearing capacity, deformability, and strain distribution of STHC composite walls. The test results demonstrated that the bearing capacity and ductility of the STHC composite walls improved with the embedding of steel tubes at the boundary elements. An analytical method was then established to predict the flexural bearing capacity of the STHC composite walls, and the calculated results agreed well with the experimental values, with errors of less than 10%. Finally, a finite element modeling (FEM) was developed via the OpenSees program to analyze the mechanical performance of the STHC composite wall. The FEM was validated through test results; additionally, the influences of the axial load ratio, steel tube strength, and shear-span ratio on the mechanical properties of STHC composite walls were comprehensively investigated.

• Steel and Composite Structures
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• v.52 no.4
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• pp.475-485
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• 2024

The mechanical behavior of the steel tube encased high-strength concrete (STHC) composite walls under constant axial load and cyclically increasing lateral load was studied. Conclusions are drawn based on experimental observations, grey evolutionary algorithm and finite element (FE) simulations. The use of steel tube wall panels improved the load capacity and ductility of the specimens. STHC composite walls withstand more load cycles and show more stable hysteresis performance than conventional high strength concrete (HSC) walls. After the maximum load, the bearing capacity of the STHC composite wall was gradually reduced, and the wall did not collapse under the influence of the steel pipe. For analysis of the bending capacity of STHC composite walls based on artificial intelligence tools, an analysis model is proposed that takes into account the limiting effect of steel pipes. The results of this model agree well with the test results, indicating that the model can be used to predict the bearing capacity of STHC composite walls. Based on a reasonable material constitutive model and the limiting effect of steel pipes, a finite element model of the STHC composite wall was created. The finite elements agree well with the experimental results in terms of hysteresis curve, load-deformation curve and peak load.

• Steel and Composite Structures
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• v.52 no.6
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• pp.647-656
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• 2024

This paper discusses the study of concrete composite walls of algorithmic modeling, in which steel tubes are embedded. The load-bearing capacity of STHC composite walls increases with the increase of axial load coefficient, but its ductility decreases. The load-bearing capacity can be improved by increasing the strength of the steel pipes; however, the elasticity of STHC composite walls was found to be slightly reduced. As the shear stress coefficient increases, the load-bearing capacity of STHC composite walls decreases significantly, while the deformation resistance increases. By analyzing actual cases, we demonstrate the effectiveness of the research results in real situations and enhance the persuasiveness of the conclusions. The research results can provide a basis for future research, inspire more explorations on seismic design and construction, and further advance the development of this field. Emphasize the importance of research results, promote interdisciplinary cooperation in the fields of structural engineering, earthquake engineering, and materials science, and improve overall seismic resistance. The emphasis on these aspects will help highlight the practical impact of the research results, further strengthen the conclusions, and promote progress in the design and construction of earthquake-resistant structures. The goals of this work are access to adequate, safe and affordable housing and basic services, promotion of inclusive and sustainable urbanization and participation, implementation of sustainable and disaster-resilient architecture, sustainable planning and management of human settlements. Simulation results of linear and nonlinear structures show that this method can detect structural parameters and their changes due to damage and unknown disturbances. Therefore, it is believed that with the further development of fuzzy neural network artificial intelligence theory, this goal will be achieved in the near future.

• Structural Engineering and Mechanics
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• v.36 no.6
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• pp.745-758
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• 2010

12 typical laminated composite reinforced concrete (RC) walls with different concrete ages and 3 cast-in-place RC walls subjected to low frequency cyclic load were carried out in this study. The failure mode, force-deformation response and energy dissipation capacity of these specimens were investigated. Differences of structural behaviours between composite RC walls and common cast-in-place RC walls were emphasized in the analysis. The compatibility of the composite specimens with different concrete ages was discussed based on the experiment. Test results indicated that the differences between the lateral bearing capacity and the displacement ductility of the composite walls and the common walls were not so obvious. Some of the composite specimen even has higher bearing capacity under the experiment loading situation. Besides, the two parts of the laminated composite specimens demonstrates incompatibility at the later loading sequence on failure mode and strain response when it is in tension. Finally, this laminated composite shear walls are suggested to be applied in rapid reconstruction structures which is not very high.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.201-211
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• 2001

The influence of aerated oil on high-speed journal bearing is examined by classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of aerated oil in fluid-film bearing. Convection to the walls, mixing with supply oil and re-circulating oil, and some degree of journal misalignment are considered. The considered Parameters for the study of bubbly lubrication are oil aeration level, air bubble size, shaft misalignment and shaft speed. The results show that deliberate oil aeration can more clearly bring on the increasing load capacity under high-speed operation of plain journal hearing than previous normal speed operation. And the load capacity may be increased more by oil aeration under the conditions of shaft misalignment and the increasing speed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.93-98
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• 2000

Turbulence on the journal bearing operation is examined. And the thermal variability is studied for isothermal, convective and adiabatic conditions on the walls within some degree of journal misalignment. An efficient algorithm for the solution of the coupled turbulent Reynolds and energy equations is used to examine the effects of the various factors. The calculation data of turbulent analysis are compared with the ones of laminar analysis. Heat convection is found to play but a small role in determining friction and load. The friction distribution patterns through inside a journal bearing now appear different with high values at the front part of the bearing due to the high speed and low temperature, and a sudden decrease past the pressure maximum.

• Tribology and Lubricants
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• v.16 no.3
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• pp.208-217
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• 2000

Turbulence in journal bearing operation is examined and the thermal variability is studied for isothermal, convective and adiabatic conditions on the walls within some degree of journal misalignment. An efficient algorithm for the solution of the coupled turbulent Reynolds and energy equations is used to examine the effects of the various factors. The calculation data of turbulent analysis are compared with those of laminar analysis. Heat convection is found to play but a small role in determining friction and load. The friction distribution patterns through the journal bearing are now different with high values at the upstream region of the bearing due to the high speed and low temperature, and a sudden decrease past the pressure maximum.

• KSTLE International Journal
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• v.7 no.2
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• pp.35-44
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• 2006

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure, then the friction and load of journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.