Simplified probabilistic seismic assessment of dampers in tall and braced structures in buildings

2020 ◽  
Vol 18 (5) ◽  
pp. 1037-1052
Author(s):  
Tanuja Singh ◽  
Megha Kalra ◽  
Anil Kumar Misra
Keyword(s):  
Industrial Structure ◽  
Vibration Reduction ◽  
Steel Structures ◽  
Base Shear ◽  
Content Type ◽  
Fluid Viscous Dampers ◽  
Adjacent Buildings ◽  
Story Drift ◽  
Probabilistic Seismic Assessment ◽  
Resistant Structure

Purpose The paper aims to focus on adjacent buildings response, equipped with damper, to analyze the vibration reduction in the nearby buildings. The nearby buildings were also equipped with dampers. The occurrence of adjacent buildings with adequate or inadequate space in between is a common phenomenon. However, many a times not much attention is paid to provide or check gap adequacy or to connect the two buildings suitably to avoid pounding of two structures on each other. This study emphasizes the utility of providing a damper in between two adjacent buildings for better performance. Design/methodology/approach The two steel structures taken for study are prototype of two structures normally found in industrial structure such as power plant, where in one of boiler structure is often tall and braced and short structure of turbine building which is moment resistant, modeled in SAP. There could be similar such structures which are often connected to a platform or a walkway with a sliding end, so as not to transfer horizontal force to other structures. If the advantage of stiffness of tall braced structure is taken into account, shorter structure can be suitably connected to braced structure to transfer forces during seismic cases under nonlinear conditions, thereby avoiding pounding (incase gap is too less), reducing response and thus optimizing the section sizes. The structures were subjected to El Centro earthquake, to simulate MCE (which could be the other site TH scaled up as desired for real site PGA), and damper location and parameters were varied to find optimum value which offers reduced base shear, reduced top floor displacement and minimum inter story drift and highest energy absorption by fluid viscous dampers. Findings The findings show that taller structures, which are braced, have more stiffness; the effect of damper is more pronounced in reducing displacement of shorter moment resistant structure to the tune of 60%, with suitably defined Cd value which is found to be 600 KNs/m for the present study. Thus, advantage of stiffener structure is taken to leverage and reduce the displacement of shorter moment resistant structure in reducing its displacement under nonlinear conditions of seismic case. Originality/value This work shows the original findings, of the adjacent buildings response, equipped with damper, to analyze the vibration reduction on other buildings which were planned to be constructed nearby.

On the effect of reduced boundary elements in steel shear walls

2017 ◽  
Vol 8 (1) ◽  
pp. 2-24
Author(s):  
Sayed Behzad Talaeitaba ◽  
Hamed Esmaeili ◽  
Mohammad Ebrahim Torki
Keyword(s):  
Load Capacity ◽  
Shear Walls ◽  
Steel Structures ◽  
Boundary Elements ◽  
Reduced Form ◽  
Base Shear ◽  
Ultimate Load Capacity ◽  
Content Type ◽  
Local Boundary ◽  
Stiffness Reduction

Purpose Steel shear walls have recently received exclusive remark. Respective of most building code requirements, design of shear wall vertical boundary elements (VBEs) and local boundary elements (LBEs) against web yielding triggers exaggerated stiffness. The extent of stiffness reduction effects in boundary elements thus calls for more exhaustive investigation. The paper aims to discuss these issues. Design/methodology/approach To this end, FEM-based push-over curves demonstrating base shear vs roof displacement, and von Mises plastic strains were scrutinized in half-scale and full-size models. Analyses were in perfect conformity with experimental data. Findings With reference to the AISC requirement, up to 35 percent decrease in the VBE moments of inertia could be imparted in higher levels without the ultimate load capacity nor displacement to failure being reduced. Also considered was open shear walls with reduced or minimum-design LBEs, the latter being used in continuous or abridged form. LBEs could be used with a moment of inertia 80 percent smaller than required if only used in a continuous form. The effect due to opening geometry was negligible on loading capacity but distinguished on the post-yielding buckling-induced softening. Practical implications Light-weight design of low- to medium-level steel structures against earthquake loads. Originality/value With respect to continuous walls, the results are more comprehensive than those existing in the literature in that they combine the effects due to scale and orientation (horizontal or vertical) of boundary elements. The results for open shear walls are not only comprehensive but also original in a sense that they account for the influences induced by the opening type (door or window), orientation (horizontal or vertical), and design (full-length or abridged) of boundary elements, in reduced form, on the lateral stiffness of the frame.

Intensity-Reduced Design for Structure with Fluid Viscous Dampers

2014 ◽  
Vol 638-640 ◽  
pp. 1818-1821
Author(s):  
Da Hai Zhao ◽  
Li Li Tong ◽  
Yong Qi Chen ◽  
Zhen Qiang Zhang
Keyword(s):  
Design Procedure ◽  
Dynamic Responses ◽  
Wall Structure ◽  
Analysis Model ◽  
Base Shear ◽  
Reinforced Concrete Frame ◽  
Viscous Dampers ◽  
Concrete Frame ◽  
Fluid Viscous Dampers ◽  
Story Drift

The intensity-reduced method based on fluid viscous dampers is proposed in this study. The analysis model of fluid viscous dampers is firstly introduced. The intensity-reduced design procedure is thoroughly discussed. Taking an 11-story reinforced concrete frame shear-wall structure as example, the intensity-reduced method is implemented in this study. The dynamic responses of the structure with and without fluid viscous dampers, including the maximum inter-story drift angle, base shear force, are discussed. The results show that the proposed intensity-reduced method for structure with fluid viscous dampers is feasible, and the responses of structure satisfy the code for seismic design of buildings. The earthquake input energy is mainly dissipated by fluid viscous dampers, which guarantees the safety of the main structure.

Analysis of Multi-Story Buildings with Hybrid Shear Wall - Steel Bracing Structural System

2021 ◽  
Author(s):  
Shubam Sharma ◽  
Aditya Kumar Tiwary
Keyword(s):  
Finite Element ◽  
Shear Walls ◽  
Steel Structures ◽  
Lateral Load ◽  
Structural System ◽  
Base Shear ◽  
Time Period ◽  
Story Drift ◽  
Overturning Moment ◽  
Comparative Results

Abstract Numerous studies were contemplated on the structures with distinctive structural configuration and ample amount of work is currently being performed through the investigation of the response of individual behavior of shear walls and bracings by varying configurations and their material properties. Seismic design philosophies had mentioned firmly that a structure must accomplish Life Safety (LS) and Performance Level (PL) for both reinforced concrete and steel structures. This study is anchored on prevailing lateral load resisting system which is virtuous but not adequate to retain vigorous ground motion or acceleration. To overwhelm this problem, an attempt was made to familiarize a new lateral load resisting system formulated by the amalgamation of two different existing lateral load resisting systems, specifically shear walls and bracings. The hybrid structural system embraces two distinctive lateral load resisting techniques, shear walls, and bracings for moment-resisting frame. A numerical finite element study was carried out by the linear dynamic method on the response of structure subjected to seismic condition and an optimal configuration of the different structural patterns is assured by using numerous possible patterns of a hybrid structural system using finite element-based software. The criteria contemplated for study including time period, base shear, overturning moment, story drift ratio, and story displacement are compared with different models and the optimal structure is concluded based upon the recital. The comparative results revealed that there is a reduction noticed in the fundamental time period, and story displacement, where as there is negligible increment in base shear and overturning moment for the hybrid structural system as compared to other configurated models.

scholarly journals Mitigating the seismic pounding of multi-story buildings in series using linear and nonlinear fluid viscous dampers

2021 ◽  
Vol 21 (4) ◽  
Author(s):  
Hytham Elwardany ◽  
Robert Jankowski ◽  
Ayman Seleemah
Keyword(s):  
Substantial Improvement ◽  
Point Of View ◽  
Steel Buildings ◽  
Viscous Dampers ◽  
Element Analysis ◽  
Fluid Viscous Dampers ◽  
Adjacent Buildings ◽  
In Series ◽  
Linear And Nonlinear ◽  
Nonlinear Fluid

AbstractSeismic-induced pounding between adjacent buildings may have serious consequences, ranging from minor damage up to total collapse. Therefore, researchers try to mitigate the pounding problem using different methods, such as coupling the adjacent buildings with stiff beams, connecting them using viscoelastic links, and installing damping devices in each building individually. In the current paper, the effect of using linear and nonlinear fluid viscous dampers to mitigate the mutual pounding between a series of structures is investigated. Nonlinear finite-element analysis of a series of adjacent steel buildings equipped with damping devices was conducted. Contact surfaces with both contactor and target were used to model the mutual pounding. The results indicate that the use of linear or nonlinear dampers leads to the significant reduction in the response of adjacent buildings in series. Moreover, the substantial improvement of the performance of buildings has been observed for almost all stories. From the design point of view, it is concluded that dampers implemented in adjacent buildings should be designed to resist maximum force of 6.20 or 1.90 times the design independent force in the case of using linear or nonlinear fluid viscous dampers, respectively. Also, designers should pay attention to the design of the structural elements surrounding dampers, because considerable forces due to pounding may occur in the dampers at the maximum displaced position of the structure.

Impact of marine industrial structure on environmental efficiency

2020 ◽  
Vol 31 (1) ◽  
pp. 111-129 ◽  
Author(s):  
Shuhong Wang ◽  
Lu Xing ◽  
Hanxue Chen
Keyword(s):  
Human Capital ◽  
Economic Development ◽  
Ownership Structure ◽  
Industrial Structure ◽  
Environmental Efficiency ◽  
Content Type ◽  
Development Level ◽  
Marine Economy ◽  
Marine Environmental ◽  
Land Economic

Purpose Recently, China has been paying increasing attention to how to improve the efficiency of the marine environment and realize a green and sustainable development of the marine economy. Consequently, the industrial structure is crucial to improving efficiency. The purpose of this paper is to introduce environmental factors into the efficiency analysis framework and explore the relationship between marine industrial structure and marine environmental efficiency. Design/methodology/approach This paper uses marine economic data under the DEA-BBC model to measure the marine environmental efficiency of provinces and cities and classifies them by cluster analysis. Then, the marine industrial structure and marine environmental efficiency are studied by an econometric model with human capital, ownership structure, land economic development level, scientific research input and government intervention degree as control variables. Findings The overall level of marine environmental efficiency is relatively low in China, increasing and then decreasing over the research period. The rationalization of industrial structure and scientific research input have significant promoting effects on marine environmental efficiency, while the degree of government intervention has a significant inhibiting effect. The positive effect of human capital on efficiency depends on whether it can be successfully converted into productivity. The effects of industrial structure advancement, ownership structure and land economic development level of on the marine environmental efficiency are mixed. Originality/value The results provide a theoretical and decision-making basis for China to transform and upgrade its marine industrial structure and sustainably develop the marine economy.

Earthquake response of linear-elastic arch-frames using exact curved beam formulations

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Baran Bozyigit
Keyword(s):  
Dynamic Stiffness ◽  
Free Vibrations ◽  
Mode Shapes ◽  
Opening Angle ◽  
Earthquake Response ◽  
Response Analysis ◽  
Curved Beam ◽  
Curved Beams ◽  
Base Shear ◽  
Content Type

PurposeThis study aims to obtain earthquake responses of linear-elastic multi-span arch-frames by using exact curved beam formulations. For this purpose, the dynamic stiffness method (DSM) which uses exact mode shapes is applied to a three-span arch-frame considering axial extensibility, shear deformation and rotational inertia for both columns and curved beams. Using exact free vibration properties obtained from the DSM approach, the arch-frame model is simplified into an equivalent single degree of freedom (SDOF) system to perform earthquake response analysis.Design/methodology/approachThe dynamic stiffness formulations of curved beams for free vibrations are validated by using the experimental data in the literature. The free vibrations of the arch-frame model are investigated for various span lengths, opening angle and column dimensions to observe their effects on the dynamic behaviour. The calculated natural frequencies via the DSM are presented in comparison with the results of the finite element method (FEM). The mode shapes are presented. The earthquake responses are calculated from the modal equation by using Runge-Kutta algorithm.FindingsThe displacement, base shear, acceleration and internal force time-histories that are obtained from the proposed approach are compared to the results of the finite element approach where a very good agreement is observed. For various span length, opening angle and column dimension values, the displacement and base shear time-histories of the arch-frame are presented. The results show that the proposed approach can be used as an effective tool to calculate earthquake responses of frame structures having curved beam elements.Originality/valueThe earthquake response of arch-frames consisting of curved beams and straight columns using exact formulations is obtained for the first time according to the best of the author’s knowledge. The DSM, which uses exact mode shapes and provides accurate free vibration analysis results considering each structural members as one element, is applied. The complicated structural system is simplified into an equivalent SDOF system using exact mode shapes obtained from the DSM and earthquake responses are calculated by solving the modal equation. The proposed approach is an important alternative to classical FEM for earthquake response analysis of frame structures having curved members.

Off-office audit of natural resource assets and water pollution: a quasi-natural experiment in China

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaowei Ma ◽  
Muhammad Shahbaz ◽  
Malin Song
Keyword(s):  
Water Pollution ◽  
Big Data ◽  
Water Resources ◽  
Natural Resource ◽  
Prevention And Control ◽  
Industrial Structure ◽  
Dynamic Effect ◽  
Content Type ◽  
Audit System ◽  
And Control

PurposeThe purpose of this paper is to analyze the impact of the off-office audit of natural resource assets on the prevention and control of water pollution against a background of big data using a differences-in-differences model.Design/methodology/approachThis study constructs a differences-in-differences model to evaluate the policy effects of off-office audit based on panel data from 11 cities in Anhui Province, China, from 2011 to 2017, and analyzes the dynamic effect of the audit and intermediary effect of industrial structure.FindingsThe implementation of the audit system can effectively reduce water pollution. Dynamic effect analysis showed that the audit policy can not only improve the quality of water resources but can also have a cumulative effect over time. That is, the prevention and control effect on water pollution is getting stronger and stronger. The results of the robustness test verified the effectiveness of water pollution prevention and control. However, the results of the influence mechanism analysis showed that the mediating effect of the industrial structure was not obvious in the short term.Practical implicationsThese findings shed light on the effect of the off-office audit of natural resource assets on the prevention and control of water pollution, and provide a theoretical basis for the formulation of relevant environmental policies. Furthermore, these findings show that the implementation of the audit system can effectively reduce water pollution, which has practical significance for the sustainable development of China's economy against the background of big data.Originality/valueThis study quantitatively analyzes the policy effect of off-office auditing from the perspective of water resources based on a big data background, which differs from the existing research that mainly focuses on basic theoretical analysis.

scholarly journals How does the urban–rural income gap affect the quality of China’s economic growth?

2018 ◽  
Vol 1 (1) ◽  
pp. 136-148 ◽  
Author(s):  
Baoping Ren ◽  
Xiaojing Chao
Keyword(s):  
Economic Growth ◽  
Industrial Structure ◽  
Empirical Test ◽  
Theoretical Interpretation ◽  
Content Type ◽  
Income Gap ◽  
Rural Income ◽  
Urban Rural ◽  
Growth Quality

Purpose Based on the theoretical definition of the quality of economic growth as well as the availability and reliability of the given data, the purpose of this paper is to build an evaluation system of a regional economic growth quality on three levels: conditions, processes and results. Design/methodology/approach From the perspective of economic quality, this paper offers a theoretical interpretation on how the urban–rural income gap affects the quality of economic growth and takes an empirical test on the sample panel data from 30 provinces and regions through difference GMM and system GMM models. Findings The results show that the excessively large income gap will influence economic growth in terms of the foundation, operation and the outcome, thereby, restricting the quality of economic growth. In addition, investments in human and physical capital and improvements in terms of transport infrastructure, industrial structure and economic openness play an active role in economic growth quality, whereas government expenditure scale, financial development and the deviation of industrial structure have a negative effect. Originality/value There has been a substantial amount of experience and evidence on the research about the issue of China’s income distribution and the quantity of economic growth, whereas there are relatively fewer discussions about the income distribution and the quality of economic growth. This paper, based on what has been mentioned above, tries to give a theoretical interpretation and an empirical test to describe the relationship between urban–rural income gap and the quality of economic growth from the quality point of view.

Design optimisation for cold-formed steel residential roof truss using genetic algorithm

2018 ◽  
Vol 15 (5) ◽  
pp. 575-583
Author(s):  
Ka Yee Kok ◽  
Hieng Ho Lau ◽  
Thanh Duoc Phan ◽  
TIina Chui Huon Ting
Keyword(s):  
Genetic Algorithm ◽  
Industrial Application ◽  
Steel Structures ◽  
Single Type ◽  
Efficient Design ◽  
Design Optimisation ◽  
Content Type ◽  
Roof Truss ◽  
Cold Formed Steel ◽  
Multi Level

Purpose This paper aims to present the design optimisation using genetic algorithm (GA) to achieve the highest strength to weight (S/W) ratio, for cold-formed steel residential roof truss. Design/methodology/approach The GA developed in this research simultaneously optimises roof pitch, truss configurations, joint coordinates and applied loading of typical dual-pitched symmetrical residential roof truss. The residential roof truss was considered with incremental uniform distributed loading, in both gravitational and uplift directions. The structural analyses of trusses were executed in this GA using finite element toolbox. The ultimate strength and serviceability of trusses were checked through the design formulation implemented in GA, according to the Australian standard, AS/NZS 4600 Cold-formed Steel Structures. Findings An optimum double-Fink roof truss which possess highest S/W ratio using GA was determined, with optimum roof pitch of 15°. The optimised roof truss is suitable for industrial application with its higher S/W ratio and cost-effectiveness. The combined methodology of multi-level optimisation and simultaneous optimisation developed in this research could determine optimum roof truss with consistent S/W ratio, although with huge GA search space. Research limitations/implications The sizing of roof truss member is not optimised in this paper. Only single type of cold-formed steel section is used throughout the whole optimisation. The design of truss connection is not considered in this paper. The corresponding connection costs are not included in the proposed optimisation. Practical implications The optimum roof truss presented in this paper is suitable for industrial application with higher S/W ratio and lower cost, in either gravitational or uplift loading configurations. Originality/value This research demonstrates the approaches in combining multi-level optimisation and simultaneous optimisation to handle large number of variables and hence executed an efficient design optimisation. The GA designed in this research determines the optimum residential roof truss with highest S/W ratio, instead of lightest truss weight in previous studies.

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