• Bulletin of the Society of Naval Architects of Korea
• /
• v.17 no.2
• /
• pp.1-10
• /
• 1980

The optimal plastic design of framed structures has been treated as the minimum weight design while satisfying the limit equilibrium condition that the structure may not fail in any of the all possible collapse modes before the specified design ultimate load is reached. Conventional optimum frame designs assume that a continuous spectrum of member size is available. In fact, the vailable sections merely consist of a finite range of discrete member sizes. Optimum frame design using discrete sections has been performed by adopting the plastic collapse theory and using the Complex Method of Box. This study has presented an iterative approach to the optimal plastic design of plane structures that involves the performance of a series of minimum weight design where the limit equilibrium equation pertaining to the critical collapse mode is added to the constraint set for the next design. The critical collapse mode is found by the collapse load analysis that is formulated as a linear programming problem. This area of research is currently being studied. This study would be applied and extended to design the larger and more complex framed structures.

• Structural Engineering and Mechanics
• /
• v.73 no.6
• /
• pp.699-714
• /
• 2020

Force based design (FBD) approach is prevalent in most of the national seismic design codes world over. Direct displacement based design (DDBD) and energy based design (EBD) approaches are relatively new methods of seismic design which claims to be more rational and predictive than the FBD. These three design approaches are conceptually distinct and imparts different strength, stiffness and ductility property to structural members for same plan configuration. In present study behavioural assessment of frame of six storey RC building designed using FBD, DDBD and EBD approaches has been performed. Lateral storey forces distribution, reinforcement design and results of nonlinear performance using static and dynamic methods have been compared. For the three approaches, considerable difference in lateral storey forces distribution and reinforcement design has been observed. Nonlinear pushover analysis and time history analysis results show that in FBD frame plastic deformation is concentrated in the lower storey, in EBD frame large plastic deformation is concentrated in the middle storeys though the inelastic hinges are well distributed over the height and, in DDBD frame plastic deformation is approximately uniform over the height. Overall the six storey frame designed using DDBD approach seems to be more rational than the other two methods.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.36 no.1
• /
• pp.116-127
• /
• 1994

A reliability analysis model for the frame structure which grafts the discretized ideal plastic method to the stochastic finite element method is introduced. The proposed method simmulates realistically the sequencial occurrence of plastic hinges and yields the probability of failure directly from the geometrical and material properties of a frame structure. The presented method can also take into account the uncertainties inherent in loads and resisten- ces through the stochastic finite element technique. The analysis results are compared with those of the Monte Carlo Simmulation, the Bound Theory, and the fs-unzipping method, and show good agreement.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1993.10a
• /
• pp.131-138
• /
• 1993

To analysis machanical behavior for RC frame under monotonic & Cyclic load, it is needed to investigate elasto-plastic behavior for steel & concrete. Therefore, in this study, we idealized material model(steel and concrete) to take into account elasto-plastic, limit state, and developed structural analysis program that consider complex non-linearity. We investigated simple beam and portal frame under cyclic & monotonic loading, so we confirmed the propriety.

• Journal of Korean Society of Steel Construction
• /
• v.21 no.5
• /
• pp.483-492
• /
• 2009

In this study, nonlinear analysis of steel plane frame was performed using the refined plastic hinge method of advanced analysis techniques. In deterioration of stiffness in plastic zone, influences by flexural bending, residual stress, geometrical non-linearity, and semi-rigid connection are considered. And also, further reduced tangent modulus was used for geometrical non-linearity, top and seat angle were chosen for semi-rigid connection. Furthermore, 3 parameter power model was used for moment-rotation behaviour of beam to column connection. The loading conditions are combined with axial and lateral force and the inverse triangle distribution of lateral and eight type of analytical models were used in analysis. The results of analyses were compared with semi-rigid and rigid connection on behaviour of numerical analysis models. And also, the behaviors of frame with changes of semi-rigidity were analyzed by using the results obtained from MIIDAS-GENw.

• Earthquakes and Structures
• /
• v.9 no.4
• /
• pp.699-718
• /
• 2015

The effect of reinforcing concrete members with high strength steel bars with yield strength up to 600 MPa on the overall seismic behavior of concrete moment frames was studied experimentally and numerically. Three geometrically identical plane frame models with two bays and two stories, where one frame model was reinforced with hot rolled bars (HRB) with a nominal yield strength of 335 MPa and the other two by high strength steel bars with a nominal yield strength of 600 MPa, were tested under simulated earthquake action considering different axial load ratios to investigate the hysteretic behavior, ductility, strength and stiffness degradation, energy dissipation and plastic deformation characteristics. Test results indicate that utilizing high strength reinforcement can improve the structural resilience, reduce residual deformation and achieve favorable distribution pattern of plastic hinges on beams and columns. The frame models reinforced with normal and high strength steel bars have comparable overall deformation capacity. Compared with the frame model subjected to a low axial load ratio, the ones under a higher axial load ratio exhibit more plump hysteretic loops. The proved reliable finite element analysis software DIANA was used for the numerical simulation of the tests. The analytical results agree well with the experimental results.

• Journal of the Korea Concrete Institute
• /
• v.27 no.4
• /
• pp.353-362
• /
• 2015

Cyclic loading tests for the PC moment frame with plastic shear hinges were performed to evaluate the seismic performance. The plastic shear hinges consisted of two steel plates were installed at the mid-length of the beam to connect the PC frames. Three shear links are existed in each steel plate. The three shear links were designed using shear force corresponding to the shear capacity of 50%, 75%, and 100% of the beam shear capacity. The proposed connections showed an efficient energy dissipation capacity and good structural performance. As a result, it is reasonable to design the plastic shear hinges using design shear capacity less than 100% of the beam shear capacity.

• Journal of Korean Association for Spatial Structures
• /
• v.7 no.2 s.24
• /
• pp.35-44
• /
• 2007

The characteristics of elasto-plastic responses of a gymnasium building which is a steel braced frame with membrane roof is discussed as a basic research on the performance based seismic design of large span structures, in this paper. Under the strong earthquake motions, the formation of plastic hinges on braces attached by the bottom frame make reduce down the stresses and displacements of upper structures, and vertical acceleration of the membrane is tend to increase but maximum response of strain and corresponding stresses are tend to be reduced.

• Journal of Korean Society of Steel Construction
• /
• v.23 no.4
• /
• pp.405-415
• /
• 2011

For the safe seismic design of buildings, it is necessary to predict the plastic deformation demands of the members as well as the story drift ratio. In the present study, a simple method of estimating the beam plastic rotation was developed for special-moment-resisting steel frame structures designed with strong column-weak beam behavior. The proposed method uses elastic analysis rather than nonlinear analysis, which is difficult to use in practice. The beam plastic rotation was directly calculated based on the results of the elastic analysis, addressing the moment redistribution, the column and joint dimensions, the movement of the plastic hinge, the panel zone deformation, the gravity load, and the strain-hardening behavior. In addition, the rocking effect of the braced frame or core wall on the beam plastic rotation was addressed. For verification, the proposed method was applied to a six-story special-moment frame designed with strong column-weak beam behavior. The predicted plastic rotations of the beams were compared with those that were determined via nonlinear analysis. The beam plastic rotations that were predicted using the proposed method correlated well with those that were determined from the nonlinear pushover analysis.

• Proceedings of the KIEE Conference
• /
• 1987.11a
• /
• pp.61-66
• /
• 1987

The metals has been used to the electric motor frame and brackets. The purpose of this project is to substitute engineering plastic doter frame for metal because of the demand for small size and environmental reliability. As a result of considering of mechanical strength, heat and injection characteristic of engineering plastics. PBT GF 30 has been selected as the material of electric motor frame including brackets. Design of the frame has been carried out on enough consideration of mechanical strength, heat-resisting and endurance. For the prevention of lower efficiency, the length of airgap between stator and rotor is reduced and for the reduction of vibration, slot combination is changed and the length of stator is increased.