Papers by Keyword: Steel Frame

Abstract: Research on cooperative working performance of cold-formed steel stud wall(CFSW) and steel frame(SF) was carried out by analytical method and finite element method. The practical calculation methods of shear force and horizontal displacement for CFSW - SF structure under horizontal load were presented. The superposition principle between CFSW and SF in elastic stage was verified in terms of strength and stiffness. The investigation by FEM indicates that the shear force distribution in elastic stage is in accord with lateral stiffness of CFSW and SF, the shear force distribution rate of CFSW declines along with the increasing of horizontal displacement while thar of SF increases because lateral stiffness of SF degenerates more slowly than that of CFSW.

Abstract: The aim of this paper is to present a practical yet simplified method in the second-order analysis of semirigid connected steel frames. Based on the principle of new shear force distribution method, by taking partial frame as an analytical subassembly model and using a rotation spring which has variable bending stiffness to model flexibility of beam-column connection, this paper derives a simplified non-iterative inner force and lateral deflection computation formula considering P-Delta effects on semirigid connected steel frames. The numerical examples show that semirigid of beam-column connections obviously increases the horizontal displacement and P-Delta effect on the steel frame. Therefore the influences of semirigid connection should been considered in second-order analysis of building steel frame. The presented method is not only relatively practical and easily applicable to manual computation but also has a rather high accuracy, and can be used by the engineers in preliminary design for semirigid connected steel frames.

Abstract: In this paper, the co-rotational total Lagrangian forms of finite element formulations are derived to make elasto-plastic analysis for plane steel frames either under increasing external loading at ambient temperature or under constant external loading at elevated temperatures. Geometric nonlinearity and thermal-expansion effect are taken into account. A series of programs are developed based on the formulations. To verify the accuracy and efficiency of the nonlinear finite element programs, a couple of numerical benchmark tests are carried out. And the results are in a good agreement with solutions from literature. The effects of nonlinear terms of the stiffness matrices on the computational results are investigated in detail. It is demonstrated that the influence of geometric nonlinearity on the incremental step by step finite element analysis for plane steel frames in fire is limited.

Abstract: An finite element model (FEM) of multistory steel frame structure is established by applying ANSYS parametric design language(APDL) in this paper, where the objective function of optimization is defined as the minimum volume of a Pin framework. The optimal design are carried on by applying the optimized toolbox of ANSYS, based on analysis the situation of the most disadvantageous load combination. Several approaches have been proposed to avoid restraining to the local minimum. Experimental results show that the section size of the structural element improved obviously.

Abstract: To realize the industrialized lateral resistant system in steel structure, a low cyclic loading tests is carried out for steel frames with infill prefabricated reinforce-concrete shear walls (solid wall). The crack developed in infill walls and deformation performances of specimen are investigated. And the force transfer mechanism, failure mode, hysteretic behavior, stiffness degradation deformation and ductility and energy dissipation of composite structure are analyzed too. Test results show that the concrete crushing in infill wall is the main failure paten and the failure mode is ductile failure. Within the whole loading period, low cyclic fatigue of shear connectors (U sharp bars) doesn’t occur. The performance of the specimens including post peak strength degradation, ductility behaviors and energy dissipation, are significantly improved. In the whole test the steel and concrete components work integrally. And the specimen has good seismic performances and can be widely used in seismic areas.

Abstract: Half scaled specimen of steel frame with widen flange connection was manufactured and carried out a pseudo-dynamic experiment. Dynamic characteristics such as the base shear of the steel frame, acceleration response, displacement response of each floor and hysteresis curve were obtained through the TUT control system and data acquisition system. The results show that the acceleration response and displacement response for each floor of the steel frame with widen flange connection tally with actual projects and can well reflect the overall seismic performance of the structure. The steel frame is always in the elastic stage under the earthquake, it has stable hysteretic behavior and good energy dissipation capacity. Reinforced connection improved the seismic performance of the steel frame effectively, and the experimental results can provide reference for the engineering applications.

Abstract: Using the plastic shear deformation of panel zones (PZs) to increase the ductility and seismic energy dissipation of structures is a common practice in most countries specifications. This makes PZs generally yielding before columns and beams, and the shear deformation of PZs is relatively large. In order to explore the elasto-plastic properties of PZs, tests of different types of beam-column connections under monotonic loads were conducted firstly. Focus of tests is to explore the influence factors on elasto-plastic properties of PZs. Then based on test results and existing research data, simplified calculation methods of PZs strength and stiffness in the elastic and elasto-plastic stage were derived, and bilinear relationship expression of PZs moment-rotation was also given. Finally, the simplified calculation method for considering the effects of PZs elasto-plastic shear deformation on story drift of steel frames was presented.

Abstract: In order to hurdle the limitations of Monte Carlo method and Response Surface method, the advanced Monte Carlo method was shown in this paper. And the system reliability of a one-bay and three-story steel framework structure was analyzed using the improved Monte Carlo method. Results of reliability analysis showed that there were high precision and a short calculating time using the improved Monte Carlo method. Then, the model of optimal design for steel frame based on the system reliability was built in accordance with the improved Monte Carlo method. And the optimal design on the steel frame was shown using the modern optimization method--genetic algorithm. From results, it was proved that optimal design without reliability could make structure have not enough reliability, even would not reach the required level of structural safety of Chinese criterions. It may lead to hidden dangers when only to reach objection on economy but haven’t considering reliability.

Abstract: Simplified calculation of initial stiffness of end-plate bolted connections is given in the paper. Considering the influence of the end-plate bolted connections to the internal force of the steel portal frames, the modified elastic calculation of internal force is suggestted. Comparing with the finite element calculation results of different span steel portal frames, the calculated value is agree with the finite element calculation results. End-plate bolted connections are semi-rigid connections, and the flexibility of the connections affects the behavior of the frames, the internal force of rigid frames should be modified when semi-rigid connections used. The modified elastic calculation of internal force of the steel portal frames with end-plate bolted connections is simple and has good agree with the finite element results, which can give reference to engineering design.

Abstract: Based on the investigation of end plate and angle of semi-rigid connection in the steel frame of beam-column, an analysis of two connection type damage phenomenons, stiffness, bearing capacity and ductility, and then with the experimental results concluded above, the similarity and differences between the two semi-rigid connections can be extensively discussed. And with that， it can naturally be concluded that the end-plate connection is a good load capacity and ductility properties of semi-rigid connection type. These for, the conclusion can provide test basis for the ideal steel structure semi-rig seismic node design and application.