scholarly journals Effect of Buckling Restrained Braces Locations on Seismic Responses of High-Rise RC Core Wall Buildings

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Munir Ahmed ◽  
Shahzadi Tayyaba ◽  
Muhammad Waseem Ashraf
Keyword(s):  
Plastic Hinge ◽  
Bending Moment ◽  
Structural Components ◽  
Seismic Responses ◽  
Coupling Beams ◽  
High Rise ◽  
The Core ◽  
Energy Demands ◽  
Conventional Design ◽  
Buckling Restrained Braces

Conventionally, a flexural plastic hinge is designed and detailed at the core wall base and coupling beams ends to control the seismic responses. This strategy is based on allowing the damage to be concentrated on main structural components. To avoid such damage, an alternative strategy using energy dissipating devices (EDDs) such as buckling restrained braces (BRBs) is being studied and implemented nowadays. In this study, effect of BRBs locations on forty- (40-) story high-rise RC core wall case study building has been studied in detail using Nonlinear Response History Analysis (NLRHA) for seven spectrally matched ground motions. BRBs have been installed at critical locations identified with respect to the maximum DBE elastic modal racking shear deformation demands and force (shear and moment) demands in three different options. The force, deformation, and energy demands on structural components are compared for conventional design and different options of BRBs. The comparison with conventional design shows that BRBs not only are effective for reducing shear force demand along wall height, bending moment demand at mid height, and deformation demands by 10%, 45%, and 45%, respectively, but significantly reduce the rotation and energy demands in the core wall by 90% and 250%, respectively.

scholarly journals Numerical Modelling of Reinforced Concrete Slender Walls Subjected to Coupled Axial Tension–Flexure

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Cheng ◽  
Haoyou Zhang
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Element Model ◽  
Lateral Loading ◽  
Design Parameters ◽  
Seismic Behaviour ◽  
High Rise ◽  
Ultimate Deformation ◽  
Axial Tension ◽  
Plastic Hinge Length

AbstractUnder strong earthquakes, reinforced concrete (RC) walls in high-rise buildings, particularly in wall piers that form part of a coupled or core wall system, may experience coupled axial tension–flexure loading. In this study, a detailed finite element model was developed in VecTor2 to provide an effective tool for the further investigation of the seismic behaviour of RC walls subjected to axial tension and cyclic lateral loading. The model was verified using experimental data from recent RC wall tests under axial tension and cyclic lateral loading, and results showed that the model can accurately capture the overall response of RC walls. Additional analyses were conducted using the developed model to investigate the effect of key design parameters on the peak strength, ultimate deformation capacity and plastic hinge length of RC walls under axial tension and cyclic lateral loading. On the basis of the analysis results, useful information were provided when designing or assessing the seismic behaviour of RC slender walls under coupled axial tension–flexure loading.

Cysts of unknown etiology in marine fishes of the Northwest Atlantic and Gulf of Mexico

1987 ◽  
Vol 65 (2) ◽  
pp. 296-303 ◽  
Author(s):  
Sharon A. MacLean ◽  
Carol M. Morrison ◽  
Robert A. Murchelano ◽  
Sherie Everline ◽  
Joyce J. Evans
Keyword(s):  
Unknown Etiology ◽  
Ground Substance ◽  
Structural Components ◽  
Electron Microscopic ◽  
Sand Lance ◽  
Atlantic Mackerel ◽  
The Core ◽  
Sudan Black B ◽  
Silver Hake ◽  
Feulgen Technique

Results of light and electron microscopic examinations of cysts of unknown etiology (CUEs) occurring in the gills of Atlantic mackerel, red hake, white hake, cod, haddock, and silver hake are presented. CUEs were found also in gills and viscera of winter flounder, Atlantic croaker, spot, windowpane flounder, and sand lance. CUEs measured 150–400 μm in diameter and consisted of an external fibrous cuticle, usually a thick median band, and a central core that frequently contained eosinophilic vesicles. Structures resembling mitochondria were found in the band and in vesicles of the core, but no other organelles were apparent. Cytochemical staining and ultramicroscopy revealed aggregates of glycogen in the core ground substance; no structural components were stained with Sudan black B or by the Feulgen technique. Extensive encapsulation of CUEs by fibroblasts was typical. Of 717 mackerel examined, 76.8% had CUEs in the gills; numbers ranged from 1 to 353 per fish. The prevalence and intensity of occurrence of CUEs increased with the age of the mackerel.

scholarly journals Models of resource planning during formation of calendar construction plans for erection of high-rise buildings

2018 ◽  
Vol 33 ◽  
pp. 03032
Author(s):  
Irina Pocebneva ◽  
Vadim Belousov ◽  
Irina Fateeva
Keyword(s):  
Network Models ◽  
Resource Planning ◽  
Resource Consumption ◽  
Time Analysis ◽  
Resource Model ◽  
High Rise ◽  
The Core ◽  
Wide Range ◽  
Construction Plans

This article provides a methodical description of resource-time analysis for a wide range of requirements imposed for resource consumption processes in scheduling tasks during the construction of high-rise buildings and facilities. The core of the proposed approach and is the resource models being determined. The generalized network models are the elements of those models, the amount of which can be too large to carry out the analysis of each element. Therefore, the problem is to approximate the original resource model by simpler time models, when their amount is not very large.

Viscoelastic Coupling Dampers for Enhanced Multiple Seismic Hazard Level Performance of High-Rise Buildings

2018 ◽  
Vol 34 (4) ◽  
pp. 1847-1867 ◽  
Author(s):  
Renée MacKay-Lyons ◽  
Constantin Christopoulos ◽  
Michael Montgomery
Keyword(s):  
Seismic Hazard ◽  
Structural Damage ◽  
Time History ◽  
Coupled System ◽  
Nonlinear Time History Analysis ◽  
Coupling Beams ◽  
Restoring Force ◽  
High Rise ◽  
Amplitude Maximum ◽  
Hazard Level

Viscoelastic coupling dampers (VCDs) are installed in lieu of traditional reinforced concrete (RC) coupling beams in high-rise buildings to provide distributed supplemental damping for all dynamic loading conditions without affecting the architectural layout. When distributed effectively over the height of the building, VCDs provide viscous damping in all lateral modes of vibration and an elastic restoring force that enhances the lateral stiffness of the coupled system. In this paper, a first extensive numerical case study is carried out to compare the seismic performance of a conventional coupled shear wall high-rise building to a high damping alternate of the same design in which VCDs replace all diagonal RC beams in the core to enhance its seismic resilience. The added damping from VCDs is intended to reduce the peak responses under low amplitude earthquakes, but for larger amplitude maximum credible earthquakes, the peak responses are similar; however, structural damage is greatly reduced. Three seismic hazard levels were investigated, and the results indicate that the use of VCDs reduces peak floor accelerations, story drifts, and story shears over all seismic intensities. Nonlinear time-history analysis results also highlighted the improved resilience of the VCD structure at the maximum credible seismic hazard level where the use of VCDs eliminated all damage to coupling beams that would otherwise require repair over most of the height of the building.

Characterization of Radioactive Waste From Side Structural Components of a CANDU Reactor for Decommissioning Applications in Korea

2010 ◽  
Author(s):  
Rizwan Ahmed ◽  
Gyunyoung Heo ◽  
Dong-Keun Cho ◽  
Jongwon Choi
Keyword(s):  
Radioactive Waste ◽  
Cross Sections ◽  
Reactor Core ◽  
International Standards ◽  
Monte Carlo Code ◽  
Capture Cross ◽  
Structural Components ◽  
The Core ◽  
Waste Classification ◽  
Capture Cross Sections

Reactor core components and structural materials of nuclear power plants to be decommissioned have been irradiated by neutrons of various intensities and spectrum. This long term irradiation results in the production of large number of radioactive isotopes that serve as a source of radioactivity for thousands of years for future. Decommissioning of a nuclear reactor is a costly program comprising of dismantling, demolishing of structures and waste classification for disposal applications. The estimate of radio-nuclides and radiation levels forms the essential part of the whole decommissioning program. It can help establishing guidelines for the waste classification, dismantling and demolishing activities. ORIGEN2 code has long been in use for computing radionuclide concentrations in reactor cores and near core materials for various burn-up-decay cycles, using one-group collapsed cross sections. Since ORIGEN2 assumes a constant flux and nuclide capture cross-sections in all regions of the core, uncertainty in its results could increase as region of interest goes away from the core. This uncertainty can be removed by using a Monte Carlo Code, like MCNP, for the correct calculations of flux and capture cross-sections inside the reactor core and in far core regions. MCNP has greater capability to model the reactor problems in much realistic way that is to incorporate geometrical, compositional and spectrum information. In this paper the classification of radioactive waste from the side structural components of a CANDU reactor is presented. MCNP model of full core was established because of asymmetric structure of the reactor. Side structural components of total length 240 cm and radius 16.122 cm were modeled as twelve (12) homogenized cells of 20 cm length each along the axial direction. The neutron flux and one-group collapsed cross-sections were calculated by MCNP simulation for each cell, and then those results were applied to ORIGEN2 simulation to estimate nuclide inventory in the wastes. After retrieving the radiation level of side structural components of in- and ex-core, the radioactive wastes were classified according to the international standards of waste classification. The wastes from first and second cell of the side structural components were found to exhibit characteristics of class C and Class B wastes respectively. However, the rest of the waste was found to have activity levels as that of Class A radio-active waste. The waste is therefore suitable for land disposal in accordance with the international standards of waste classification and disposal.

Seismic Performance Assessment of Long Span Continuous Rigid Bridge

2013 ◽  
Vol 353-356 ◽  
pp. 2033-2038
Author(s):  
Qi Wen Jin ◽  
Tong Ning Wang ◽  
Yi Li Sun ◽  
Zhao Tong Hu
Keyword(s):  
Pile Foundation ◽  
Plastic Hinge ◽  
Bending Moment ◽  
Internal Force ◽  
Seismic Capacity ◽  
Seismic Performance Assessment ◽  
Soil Function ◽  
Long Span ◽  
Rigid Frame ◽  
Cantilever Construction

Based on the theory of cantilever construction, combined with a three cross continuous rigid frame bridge, choosing the biggest cantilever stage, side span cross fold stages, middle span cross fold stage and complete bridge stage as the research object. Considering the pillar-soil function, making the seismic elastic-plastic response calculation. Getting the result that, during the earthquake, pillar-soil function can improve the flexible extension ability of the bridge structure so as to get better resistance seismic capacity. Internal force of the construction stage gradually reduces along the bottom pier, the middle pier and the top pier. Along the bridge, the maximum bending moment appears at the biggest cantilever stage. Horizontal to the bridge, the maximum bending moment appears at the side span cross fold stages. Plastic areas develops quickly during pier bottom and pile top, the crack is obvious; Plastic hinge first appears in the pile foundation, consuming earthquake energy through its plastic deformation so as to reduce the earthquake impact of pier. We should try to avoid plasticitys appearing in the pile foundation during the design, which will provide convenience for the follow-up maintenance.

Nonlinear Finite Element Analysis of U Shaped Steel Plate Reinforced Concrete Coupling Beams

2013 ◽  
Vol 831 ◽  
pp. 141-144
Author(s):  
Kang Min Lee ◽  
Liu Yi Chen ◽  
Rui Li ◽  
Keun Yeong Oh ◽  
Young Soo Chun
Keyword(s):  
Finite Element ◽  
Construction Projects ◽  
Nonlinear Behavior ◽  
Coupling Beams ◽  
Element Analysis ◽  
High Rise ◽  
Finite Element Software ◽  
Small Depth ◽  
Steel Composite ◽  
Current Standards

Coupling beams have been used in high-rise shear wall buildings widely, which take great advantages of high stiffness, small lateral deformation and easy to satisfy with bearing capacity. Coupling beams exhibit different performance with deep beams, which always have small depth-to-span ratio. According to current standards coupling beams shall be reinforced with two intersecting groups of diagonally placed bars symmetrical along the midspan. It's always hard to optimize construction projects. This paper used the finite element software (Abaqus) to analysis and simulate the nonlinear behavior of steel composite reinforcement and compared the results to the current standards.

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