• 한국공간구조학회지
• /
• 제1권1호
• /
• pp.34-42
• /
• 2001

The development of contemporary spatial structures for long-span roofs in China was initiated in the 19505. Space trusses, reticulated shells and cable suspended structures have been developing rapidly since 1980s. Recently there has been a growing interest in tensile membrane structures. Comprehensive theoretical study has been carried out parallel to the engineering application, which provided necessary theoretical support to the development of different types of spatial structures.

• Structural Engineering and Mechanics
• /
• 제17권3_4호
• /
• pp.493-526
• /
• 2004

Semiactive control systems have received considerable attention for protecting structures against natural hazards such as strong earthquakes and high winds, because they not only offer the reliability of passive control systems but also maintain the versatility and adaptability of fully active control systems. Among the many semiactive control devices, magnetorheological (MR) fluid dampers comprise one particularly promising class. In the field of civil engineering, much research and development on MR fluid damper-based control systems has been conducted since this unique semiactive device was first introduced to civil engineering applications in mid 1990s. In 2001, MR fluid dampers were applied to the full-scale in-service civil engineering structures for the first time. This state-of-the-art paper includes a detailed literature review of dynamic models of MR fluid dampers for describing their complex dynamic behavior and control algorithms considering the characteristics of MR fluid dampers. This extensive review provides references to semiactive control systems using MR fluid dampers. The MR fluid damper-based semiactive control systems are shown to have the potential for mitigating the responses of full-scale civil engineering structures under natural hazards.

• Structural Engineering and Mechanics
• /
• 제84권2호
• /
• pp.285-293
• /
• 2022

Lumped damage mechanics (LDM) is a recent nonlinear theory with several applications to civil engineering structures, such as reinforced concrete and steel buildings. LDM apply key concepts of classic fracture and damage mechanics on plastic hinges. Therefore, the lumped damage models are quite successful in reproduce actual structural behaviour using concepts well-known by engineers in practice, such as ultimate moment and first cracking moment of reinforced concrete elements. So far, lumped damage models are based in the strain energy equivalence hypothesis, which is one of the fictitious states where the intact material behaviour depends on a damage variable. However, there are other possibilities, such as the energy equivalence hypothesis. Such possibilities should be explored, in order to pursue unique advantages as well as extend the LDM framework. Therewith, a lumped damage model based on the energy equivalence hypothesis is proposed in this paper. The proposed model was idealised for reinforced concrete structures, where a damage variable accounts for concrete cracking and the plastic rotation represents reinforcement yielding. The obtained results show that the proposed model is quite accurate compared to experimental responses.

• Coupled systems mechanics
• /
• 제10권6호
• /
• pp.475-490
• /
• 2021

With glass becoming a structural material there is a whole new approach for loading and ensuring the safety of construction. Due to its brittle nature, it is necessary to predict all possible problems so that structural integrity would not be endangered. In this paper, different approaches to modelling the glass elements are presented with references to the advantages, disadvantages, and application of each of them. The intention is clear, there is a need to improve and simplify the design guidelines. Given the increasing use of glass in construction it is not practical to produce experimental tests each time when the verification is needed. Today, architecture is bringing us different types of structures and every project presents a new challenge for engineers. A practical and simple approach is crucial for progress and efficiency. In this paper, different approaches to modelling glass are presented with an emphasis on soft body impact.

• Earthquakes and Structures
• /
• 제25권5호
• /
• pp.369-383
• /
• 2023

Seismic resilience (SR) plays a vital role in evaluating and improving performance losses along with saving repair costs of structures from potential earthquakes. To further explore the developments, hotspots, and trend directions of SR, a total of 901 articles are obtained from the Web of Science (WoS) database. CiteSpace software is used to conduct a bibliometric analysis, which indicates an upward trend of publications in SR and explores the relationship of countries, journals, cited references, and keywords based on visual maps and detailed tables. Then, based on the results of the bibliometric analysis, a state-of-the-art review is conducted to further explore the current challenges and trend directions of SR. The trend directions can be divided into five categories: (a) SR assessments of infrastructure structures, (b) multi-hazard quantifications of SR, (c) seismic resilient structures, (d) refining and calibrating analytical models, and (e) multi-criteria decision-making frameworks for sustainability and SR.

• Steel and Composite Structures
• /
• 제16권2호
• /
• pp.117-133
• /
• 2014

Natural vibration of truss cable structures is analyzed based upon the general structural analysis software ANSYS, energy variational method and Rayleigh method, the calculated results of three methods are compared, from which the characteristics of free-vibration are obtained. Moreover, vertical seismic response analysis of truss cable structures is carried out via time-history method. Introducing three natural earthquake waves calculated the results including time-history curve of vertical maximal displacement, time-history curve of maximal internal force. Variation curve of maximal displacement of node along span, and variation curve of maximal internal force of member along span are presented. The results show the formulas of frequencies for truss cable structures obtained by energy variational method are of high accuracy. Furthermore, the maximal displacement and the maximal internal force occur near the 1/5 span point. These provide convenient and simple design method for practical engineering.

• Structural Engineering and Mechanics
• /
• 제68권4호
• /
• pp.475-483
• /
• 2018

Square tubular columns are commonly used in moment resisting frames, while through-diaphragm connection is the most typical configuration detail to connect the H-shaped beam to the column. However, brittle fracture normally occurs at the complete joint penetration weld between the beam flange and the through-diaphragm due to the stress concentration caused by the geometrical discontinuity. Accordingly, three improved types of through-diaphragm are presented in this paper to provide smooth force flow path comparing to that of conventional connections. Tensile tests were conducted on four specimens and the results were analyzed in terms of failure modes, load-displacement response, yield and ultimate capacity, and initial stiffness. Furthermore, strain distributions on the through-diaphragm, the beam flange plate, and the column face were comprehensively evaluated and discussed. It was found that all the proposed three types of improved through-diaphragm connections were able to reduce the stress concentration in the welds between the beam flange and the through-diaphragm. Furthermore, the stress distribution in connection with longer tapered through-diaphragm was more uniform.

• Computers and Concrete
• /
• 제13권5호
• /
• pp.603-619
• /
• 2014

Soft storey buildings are characterised by having a storey that has a large amount of open space. This soft storey creates a major weak point during an earthquake. As the soft stories are typically associated with retail spaces and parking garages, they are often on the lower levels of tall building structures. Thus, when these stories collapse, the entire building can also collapse, causing serious structural damage that may render the structure completely unusable. The use of special soft storey is predominant in the tall building structures constructed by several local developers, making the issue important for local building structures. In this study, the effect of the incorporation of an isolator on the seismic behaviour of tall building structures is examined. The structures are subjected to earthquakes typical of the local city, and the isolator is incorporated with the appropriate isolator time period and damping ratio. A FEM-based computational relationship is proposed to increase the storey height so as to incorporate the isolator with the same time period and damping ratio for both a lead rubber bearing (LRB) and high-damping rubber bearing (HDRB). The study demonstrates that the values of the FEM-based structural design parameters are greatly reduced when the isolator is used. It is more beneficial to incorporate a LRB than a HDRB.

• Smart Structures and Systems
• /
• 제16권6호
• /
• pp.981-1002
• /
• 2015

For vibration control of civil structures, especially large civil structures, one of the important issues is how to place a minimal number of actuators and sensors at their respective optimal locations to achieve the predetermined control performance. In this paper, a methodology is presented for the determination of the minimal number and optimal location of actuators and sensors for vibration control of building structures under earthquake excitation. In the proposed methodology, the number and location of the actuators are first determined in terms of the sequence of performance index increments and the predetermined control performance. A multi-scale response reconstruction method is then extended to the controlled building structure for the determination of the minimal number and optimal placement of sensors with the objective that the reconstructed structural responses can be used as feedbacks for the vibration control while the predetermined control performance can be maintained. The feasibility and accuracy of the proposed methodology are finally investigated numerically through a 20-story shear building structure under the El-Centro ground excitation and the Kobe ground excitation. The numerical results show that with the limited number of sensors and actuators at their optimal locations, the predetermined control performance of the building structure can be achieved.

• Advances in materials Research
• /
• 제12권2호
• /
• pp.161-177
• /
• 2023

This paper proposes an analytical method to investigate the free vibration behaviour of new functionally graded (FG) carbon nanotubes reinforced composite beams based on a higher-order shear deformation theory. Cosine functions represent the material gradation and material properties via the thickness. The kinematic relations of the beam are proposed according to trigonometric functions. The equilibrium equations are obtained using the virtual work principle and solved using Navier's method. A comparative evaluation of results against predictions from literature demonstrates the accuracy of the proposed analytical model. Moreover, a detailed parametric analysis checks for the sensitivity of the vibration response of FG nanobeams to nonlocal length scale, strain gradient microstructure-scale, material distribution and geometry.