The Effect of Element Types on Force Analogy Method Analysis

In this study, the seismic performance of a 2D portal frame subjected to the recorded seismic ground motions of the Northridge 1994 earthquake was evaluated by the force analogy method (FAM) with different element types. To increase the accuracy of FAM, Timoshenko (TS) elements were employed instead of the classical Euler Bernoulli (EB) elements, to revert the shear deformations that are neglected in EB elements. To perform evaluation, the same material and section properties were considered and the same portal frame was analyzed with different element lengths, from 0.5 to 7.0 m in 0.5 m steps

Optimization of earthquake energy dissipation system by genetic algorithm

Numerous recent studies have assessed the stability and safety of structures furnished with different types of structural control systems, such as viscous dampers. A challenging issue in this field is the optimization of structural control systems to protect structures against severe earthquake excitation. As the safety of a structure depends on many factors, including the failure of structural members and movement of each structural node in any direction, the optimization technique must consider many parameters simultaneously. However, the available literature on optimizing earthquake energy dissipation systems shows that most researchers have considered optimization processes using just one or a few parameters applicable only to simple SDOF or MDOF systems. This article reports on the development of a multiobjective optimization procedure for structural passive control systems based on genetic algorithm; this research focused on systems that would minimize the effects of earthquake based on realistic structural responses considering plastic hinge occurrence in structural elements and three-directional displacement in all structural nodes. The model was applied to an example of three-dimensional reinforced concrete framed building and its structural seismic responses were investigated. The results showed that the optimized control system effectively reduced the seismic response of structures, thus enhancing building safety during earthquake excitations

The Effect of Element Types on Force Analogy Method Analysis

In this study, the seismic performance of a 2D portal frame subjected to the recorded seismic ground motions of the Northridge 1994 earthquake was evaluated by the force analogy method (FAM) with different element types. To increase the accuracy of FAM, Timoshenko (TS) elements were employed instead of the classical Euler Bernoulli (EB) elements, to revert the shear deformations that are neglected in EB elements. To perform evaluation, the same material and section properties were considered and the same portal frame was analyzed with different element lengths, from 0.5 to 7.0 m in 0.5 m steps

A Novel Algorithm for Effective Vibration Control of Portal Frames

Severe vibrations such as earthquakes threaten to demolish or cause damage to built structures during their lifetime. Mitigation of such damage can be done by using control devices such as actuators. In this paper, an algorithm is proposed to analyze the nonlinear behavior of a portal frame supported by an actuator. The results were compared with those for a frame without actuator. The algorithm was developed in accordance with the Timoshenko beam element theory. ANSYS verified the results for the cases of a frame supported by a damper element and a frame without actuator. The results support the efficiency of the algorithm in reducing frame vibration and top-node displacement

A Novel Algorithm for Effective Vibration Control of Portal Frames

Severe vibrations such as earthquakes threaten to demolish or cause damage to built structures during their lifetime. Mitigation of such damage can be done by using control devices such as actuators. In this paper, an algorithm is proposed to analyze the nonlinear behavior of a portal frame supported by an actuator. The results were compared with those for a frame without actuator. The algorithm was developed in accordance with the Timoshenko beam element theory. ANSYS verified the results for the cases of a frame supported by a damper element and a frame without actuator. The results support the efficiency of the algorithm in reducing frame vibration and top-node displacement

Evaluation of the effect of shear wall distribution in seismic response of precast framed structure

In this research an attempt has been made to evaluate response of frame structure, subjected to lateral loads such as earthquake with different arrangement of Reinforced Concrete (RC) shear wall in structural plan. For this purpose a ten stories precast building skeletal frame of typical JKR (Public Work Department of Malaysia) quarters is considered and its behavior with different shear wall location under earthquake excitation is studied and comparison of performance has been made. Placement of shear wall did helps a lot in restraint the lateral displacement at tip node. Skeletal frame with original shear wall based on JKR quarters showed the best performance among all although there is only little different in term of shear forces and bending moments in beams

ROUTE SELECTION AND TRADE-OFFS EVALUATION OF THE INTERMODAL FREIGHT TRANSPORTATION

Identification of optimum routes and mode of transport play vital roles in freight transport decision making. This paper presents the research carried out for the modelling and analysis of intermodal transport network. The study evaluates the trade-offs associated with different modes of freight transportation. Geographic Information System (GIS) and MATLAB were applied to design the hypothetical intermodal freight transportation network, modelling, analysis and user-interface design. An optimum route and transport mode for different pairs of origins and destinations were determined across decision objectives such as distance, time, emission and cost. The trade-offs among different modes of freight transportation were explored. Based on the assumptions of this study, the results showed that the road was the fastest mode, while waterway was not only the most costefficient but also was the most environmental-friendly transport mode in terms of carbon dioxide emission. Although the transport network of the study was small size and hypothetical, this paper demonstrates the potentiality of this methodology for analysing larger and real intermodal networks

DEVELOPMENT OF FORCE ANALOGY METHOD FOR ACTIVE VIBRATION CONTROL OF FRAMES

Maintaining the man made structures is one of the main concerns of engineers all over the world. Although many methods and ways are introduced during the past years, but most of them are expensive and black boxes. In this study, an attempt has been made to control the frame displacement subjected to earthquake ground motion. Some facts such as limitation of control systems in dissipating energy, unknown power of earthquakes, and structural aging, lead to nonlinear analysis and damaged members

DEVELOPMENT OF FORCE ANALOGY METHOD FOR ACTIVE VIBRATION CONTROL OF FRAMES

Maintaining the man made structures is one of the main concerns of engineers all over the world. Although many methods and ways are introduced during the past years, but most of them are expensive and black boxes. In this study, an attempt has been made to control the frame displacement subjected to earthquake ground motion. Some facts such as limitation of control systems in dissipating energy, unknown power of earthquakes, and structural aging, lead to nonlinear analysis and damaged members

A novel approach to enhance the accuracy of vibration control of Frames

All structures built within known seismically active regions are typically designed to endure earthquake forces. Despite advances in earthquake resistant structures, it can be inferred from hindsight that no structure is entirely immune to damage from earthquakes. Active vibration control systems, unlike the traditional methods which enlarge beams and columns, are highly effective countermeasures to reduce the effects of earthquake loading on a structure. It requires fast computation of nonlinear structural analysis in near time and has historically demanded advanced programming hosted on powerful computers. This research aims to develop a new approach for active vibration control of frames, which is applicable over both elastic and plastic material behavior. In this study, the Force Analogy Method (FAM), which is based on Hook’s Law is further extended using the Timoshenko element which considers shear deformations to increase the reliability and accuracy of the controller. The proposed algorithm is applied to a 2D portal frame equipped with linear actuator, which is designed based on full state Linear Quadratic Regulator (LQR). For comparison purposes, the portal frame is analysed by both the Euler Bernoulli and Timoshenko element respectively. The results clearly demonstrate the superiority of the Timoshenko element over Euler Bernoulli for application in nonlinear analysis