scholarly journals Estimation of the Mechanical Parameters for a Reduced Coupled Flexural–Torsional Beam Model of a Tall Building by a Sub-Structure Approach

2021 ◽  
Vol 11 (10) ◽  
pp. 4655
Author(s):  
Federico Cluni ◽  
Stefano Fiorucci ◽  
Vittorio Gusella ◽  
Massimiliano Gioffrè
Keyword(s):  
Degrees Of Freedom ◽  
Sandwich Beam ◽  
Structural Response ◽  
Tall Buildings ◽  
Shear Walls ◽  
Deformation Energy ◽  
Tall Building ◽  
Beam Model ◽  
Dynamic Features ◽  
Stochastic Loads

The use of equivalent beam models to estimate the dynamical characteristics of complex tall buildings has been investigated by several authors. The main reason is the structural response estimation to stochastic loads, such as wind and earthquake, using a reduced number of degrees of freedom, which reduces the computational costs and therefore gives the designer an effective tool to explore a number of possible structural solutions. In this paper, a novel approach to calibrate the mechanical and dynamical features of a complete 3D Timoshenko beam, i.e., describing bending, shear and torsional behavior, is proposed. This approach is based on explicitly considering the sub-structures of the tall building. In particular, the frames, shear walls and lattice sub-systems are modeled as equivalent beams, constrained by means of rigid diaphragms at different floors. The overall dynamic features of the tall building are obtained by equating the deformation energy of an equivalent sandwich beam with that of the selected sub-structures. Finally, the 3D Timoshenko equivalent beam parameters are calibrated by minimizing a suitable function of modal natural frequencies and static displacements. The closed form modal solution of the equivalent beam model is used to obtain the response to stochastic loads.

Coupled torsional dynamic analysis of a multistory building

1973 ◽  
Vol 63 (3) ◽  
pp. 1025-1039
Author(s):  
Bruce M. Douglas ◽  
Thomas E. Trabert
Keyword(s):  
Ground Motion ◽  
Degrees Of Freedom ◽  
Seismic Waves ◽  
Structural Response ◽  
Tall Buildings ◽  
Strong Motion ◽  
Ambient Vibration ◽  
Simultaneous Application ◽  
Vibration Data ◽  
Horizontal Ground Motion

abstract The coupled bending and torsional vibrations of a relatively symmetric 22-story reinforced concrete building in Reno, Nevada are studied. Analytical results are compared with observations obtained during the nuclear explosion FAULTLESS and to ambient vibration data. The fundamental periods of vibration observed during FAULTLESS were (TNS = 1.42, TEW = 1.81, TTORSION = 1.12 sec), and the calculated periods were (TNS = 2.14, TEW = 2.07, TTORSION = 1.90 sec). It was estimated that between 25 and 45 per cent of the total available nonstructural stiffness was required to explain the differences in the observed and calculated fundamental periods. Each floor diaphragm in the system was allowed three degrees of freedom-two translations and a rotation. It was found that coupled torsional motions can influence the response of structural elements near the periphery of the structure. Strong-motion structural response calculations comparing the simultaneous use of both components of horizontal ground motion to a single component analysis showed that the simultaneous application of both components of ground motion can significantly alter the response of lateral load-carrying elements. Differences of the order of 45 per cent were observed in the frames near the ends of the structure. Also, it was shown that the overall response of tall buildings is sensitive not only to the choice of input ground motion but also to the orientation of the structure with respect to the seismic waves.

scholarly journals Study on Behaviour of Outrigger System on High Rise Structure by Varying Outrigger Depth in Seismic Zones of India by Using Staad Pro

2021 ◽  
pp. 420-423
Author(s):  
Mayuri N. Ade ◽  
Prof. G. D. Dhawle ◽  
Prof. M. M. Lohe
Keyword(s):  
Tall Buildings ◽  
Shear Walls ◽  
Tall Building ◽  
Lateral Stiffness ◽  
Lateral Loads ◽  
High Rise ◽  
The Core ◽  
Lateral Forces ◽  
Almost Everywhere ◽  
The World

Tall building development is rapidly growing almost everywhere in the world acquainting new difficulties that need to be met with, through engineering evaluation. In tall buildings, lateral loads generated by earthquake or wind load are frequently resisted by providing coupled shear walls. But as the height increases, the building becomes taller and the efficiency of the tall building greatly depends on lateral stiffness and resistance capacity. So, a system called outrigger is introduced which improves overturning stiffness and strength by connecting shear wall core to outer columns. When the Structure is subjected to Lateral forces, the Outrigger and the columns resist the rotation of the core and thus significantly reduce the lateral deflection and base moment, which would have arisen in a free core. During the last three decades, numerous studies have been carried out on the analysis and behaviour of outrigger structures. But this question is remained that how many outriggers system is needed in tall buildings. (Using Staad-Pro)

Assessment Method for Inelastic Higher Mode Effects in Outrigger Braced Tall Building Under Seismic Loads

2019 ◽  
Vol 11 (03) ◽  
pp. 1950024
Author(s):  
Nilupa Herath ◽  
Priyan Mendis
Keyword(s):  
Degrees Of Freedom ◽  
Tall Buildings ◽  
Assessment Method ◽  
Tall Building ◽  
Seismic Loads ◽  
Higher Mode Effects ◽  
Mode Effects ◽  
The Impact ◽  
Mode Response

Outrigger system is a more popular structural system in tall buildings and higher mode participation in such buildings is an important aspect in design. During severe earthquake impacts, buildings undergo inelastic deformations, and this can lead to lengthening of modal periods of the building. Since higher mode effects have a significant impact on the overall behavior in tall buildings, the impact due to lengthening of modal periods needs to be addressed in the design. In this study, a simple assessment method is presented to quantify the effect of higher mode response on the behavior of outrigger braced buildings under seismic loads. The method comprises of simplifying the building to vertical cantilever with lateral degrees of freedom equal to number of stories and rotational springs with equivalent spring stiffness at corresponding outrigger locations. A pin-based structure was assumed to limit the first mode response to represent the transition from elastic to inelastic status of the building. The proposed method is capable of estimating the inelastic lengthened periods for higher modes and their responses in outrigger braced tall buildings. The developed method was applied to a case study outrigger braced tall building and reasonable results are predicted.

Seismic Behavior of a Tall Building Reinforced with High Strength Bars

2019 ◽  
Author(s):  
Husain S. A. Aldahlki ◽  
Mary Beth Hueste
Keyword(s):  
Structural Response ◽  
Tall Buildings ◽  
High Strength ◽  
Tall Building ◽  
Local Response ◽  
Three Dimensional Model ◽  
Building Site ◽  
Seismic Force ◽  
Global And Local

<p>Reinforced concrete tall buildings are widely spread around the world. Tall buildings in high seismic regions have substantial capacity requirements due to both gravity loads and seismic demands that often lead to very heavily congested sections. Therefore, using high strength reinforcement with a reduced area of steel bars introduces a valuable solution. However, the tensile characteristics of high strength reinforcement differ from conventional reinforcement and may lead to differences in the structural response and behavior of structural members. Consequently, the global response of the building seismic-force-resisting system (SFRS) could vary from that of a conventional steel reinforced SFRS. This study investigates the global and local response of a tall concrete building reinforced with high strength reinforcement (Grade 100 (690 MPa)) when subject to earthquake demands. A three-dimensional model for a case study building, which is a 46-story tall building, was prepared. By using the capabilities of nonlinear analyses in OpenSees, the building model was developed and analyzed. The performance of the building reinforced with conventional and high strength reinforcement was investigated and reviewed according to the Tall Building Initiative (TBI) guidelines. Eleven different ground motions were selected and scaled to represent the Risk-Targeted Maximum Considered Earthquake (MCER) level for the case study building site. The global and local response parameters showed that the tall building reinforced with a reduced area of high strength steel (Grade 100 (690 MPa)) performed similarly to the same building reinforced with conventional reinforcement (Grade 60 (414 MPa)). The results provide information relevant to the implementation of high strength reinforcement in seismic applications and serves to increase the understanding of the resulting impacts on the structural response of a case study tall building.</p>

Influence of the distribution of the shear walls on the seismic response of the buildings

2020 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
El Mehdi Echebba ◽  
Hasnae Boubel ◽  
Oumnia Elmrabet ◽  
Mohamed Rougui
Keyword(s):  
Structural Analysis ◽  
Seismic Response ◽  
Natural Frequency ◽  
Structural Design ◽  
Structural Response ◽  
Shear Walls ◽  
Structural Elements ◽  
Analysis Software ◽  
Ansys Apdl ◽  
The Impact

Abstract In this paper, an evaluation was tried for the impact of structural design on structural response. Several situations are foreseen as the possibilities of changing the distribution of the structural elements (sails, columns, etc.), the width of the structure and the number of floors indicates the adapted type of bracing for a given structure by referring only to its Geometric dimensions. This was done by studying the effect of the technical design of the building on the natural frequency of the structure with the study of the influence of the distribution of the structural elements on the seismic response of the building, taking into account of the requirements of the Moroccan earthquake regulations 2000/2011 and using the ANSYS APDL and Robot Structural Analysis software.

Flexural Vibration of Prestressed Concrete Bridges with Corrugated Steel Webs

2017 ◽  
Vol 17 (02) ◽  
pp. 1750023 ◽  
Author(s):  
Xia-Chun Chen ◽  
Zhen-Hu Li ◽  
Francis T. K. Au ◽  
Rui-Juan Jiang
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Prestressed Concrete ◽  
Natural Frequencies ◽  
Sandwich Beam ◽  
Flexural Vibration ◽  
Concrete Bridges ◽  
Mode Shapes ◽  
Beam Model ◽  
Prestressed Concrete Bridges

Prestressed concrete bridges with corrugated steel webs have emerged as a new form of steel-concrete composite bridges with remarkable advantages compared with the traditional ones. However, the assumption that plane sections remain plane may no longer be valid for such bridges due to the different behavior of the constituents. The sandwich beam theory is extended to predict the flexural vibration behavior of this type of bridges considering the presence of diaphragms, external prestressing tendons and interaction between the web shear deformation and flange local bending. To this end, a [Formula: see text] beam finite element is formulated. The proposed theory and finite element model are verified both numerically and experimentally. A comparison between the analyses based on the sandwich beam model and on the classical Euler–Bernoulli and Timoshenko models reveals the following findings. First of all, the extended sandwich beam model is applicable to the flexural vibration analysis of the bridges considered. By letting [Formula: see text] denote the square root of the ratio of equivalent shear rigidity to the flange local flexural rigidity, and L the span length, the combined parameter [Formula: see text] appears to be more suitable for considering the diaphragm effect and the interaction between the shear deformation and flange local bending. The diaphragms have significant effect on the flexural natural frequencies and mode shapes only when the [Formula: see text] value of the bridge falls below a certain limit. For a bridge with an [Formula: see text] value over a certain limit, the flexural natural frequencies and mode shapes obtained from the sandwich beam model and the classical Euler–Bernoulli and Timoshenko models tend to be the same. In such cases, either of the classical beam theories may be used.

Machine learning-based failure mode identification of RCSPSW

2021 ◽  
Author(s):  
Dongqi Jiang ◽  
Shanquan Liu ◽  
Tao Chen ◽  
Gang Bi
Keyword(s):  
Machine Learning ◽  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Tall Buildings ◽  
Shear Walls ◽  
Superior Performance ◽  
Ann Model ◽  
Mode Recognition ◽  
Wide Range

<p>Reinforced concrete – steel plate composite shear walls (RCSPSW) have attracted great interests in the construction of tall buildings. From the perspective of life-cycle maintenance, the failure mode recognition is critical in determining the post-earthquake recovery strategies. This paper presents a comprehensive study on a wide range of existing experimental tests and develops a unique library of 17 parameters that affects RCSPSW’s failure modes. A total of 127 specimens are compiled and three types of failure modes are considered: flexure, shear and flexure-shear failure modes. Various machine learning (ML) techniques such as decision trees, random forests (RF), <i>K</i>-nearest neighbours and artificial neural network (ANN) are adopted to identify the failure mode of RCSPSW. RF and ANN algorithm show superior performance as compared to other ML approaches. In Particular, ANN model with one hidden layer and 10 neurons is sufficient for failure mode recognition of RCSPSW.</p>

Refined Mathematical Models for Across-Wind Loads of Rectangular Tall Buildings with Aerodynamic Modifications

2021 ◽  
pp. 2150131
Author(s):  
Yi Li ◽  
Chao Li ◽  
Qiu-Sheng Li ◽  
Yong-Gui Li ◽  
Fu-Bin Chen
Keyword(s):  
Wind Tunnel ◽  
Correlation Coefficients ◽  
Tall Buildings ◽  
Tall Building ◽  
Experimental Results ◽  
Dynamic Loads ◽  
Wind Loads ◽  
Empirical Formulas ◽  
Benchmark Model ◽  
Power Spectral

This paper aims to systematically study the across-wind loads of rectangular-shaped tall buildings with aerodynamic modifications and propose refined mathematic models accordingly. This study takes the CAARC (Commonwealth Advisory Aeronautical Research Council) standard tall building as a benchmark model and conducts a series of pressure measurements on the benchmark model and four CAARC models with different round corner rates (5%, 10%, 15% and 20%) in a boundary layer wind tunnel to investigate the across-wind dynamic loads of the typical tall building with different corner modifications. Based on the experimental results of the five models, base moment coefficients, power spectral densities and vertical correlation coefficients of the across-wind loads are compared and discussed. The analyzed results shown that the across-wind aerodynamic performance of the tall buildings can be effectively improved as the rounded corner rate increases. Taking the corner round rate and terrain category as two basic variables, empirical formulas for estimating the across-wind dynamic loads of CAARC standard tall buildings with various rounded corners are proposed on the basis of the wind tunnel testing results. The accuracy and applicability of the proposed formulas are verified by comparisons between the empirical formulas and the experimental results.

scholarly journals Typological diversity of tall buildings and complexes in relation to their functional structure

2018 ◽  
Vol 33 ◽  
pp. 01020 ◽  
Author(s):  
Viktor P. Generalov ◽  
Elena M. Generalova ◽  
Nadezhda A. Kalinkina ◽  
Irina V. Zhdanova
Keyword(s):  
Tall Buildings ◽  
Tall Building ◽  
Functional Structure ◽  
Sports Facilities ◽  
Functional Elements ◽  
Space Planning ◽  
Single Function ◽  
Mixed Use ◽  
Provision Of Services

The paper focuses on peculiarities of tall buildings and complexes, their typology and its formation in relation to their functional structure. The research is based on the analysis of tall buildings and complexes and identifies the following main functional elements of their formation: residential, administrative (office), hotel elements. The paper also considers the following services as «disseminated» in the space-planning structure: shops, medicine, entertainment, kids and sports facilities, etc., their location in the structure of the total bulk of the building and their impact on typological diversity. Research results include suggestions to add such concepts as «single-function tall buildings» and «mixed-use tall buildings and complexes» into the classification of tall buildings. In addition, if a single-function building or complex performs serving functions, it is proposed to add such concepts as «a residential tall building (complex) with provision of services», «an administrative (public) tall building (complex) with provision of services» into the classification of tall buildings. For mixed-use buildings and complexes the following terms are suggested: «a mixed-use tall building with provision of services», «a mixed-use tall complex with provision of services».

scholarly journals Learning data-driven reduced elastic and inelastic models of spot-welded patches

2021 ◽  
Vol 22 ◽  
pp. 32
Author(s):  
Agathe Reille ◽  
Victor Champaney ◽  
Fatima Daim ◽  
Yves Tourbier ◽  
Nicolas Hascoet ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Structural Response ◽  
Data Driven ◽  
Fine Scale ◽  
Time Step ◽  
Large Structures ◽  
Computational Performance ◽  
Local Patch ◽  
The Rich ◽  
Learning Data

Solving mechanical problems in large structures with rich localized behaviors remains a challenging issue despite the enormous advances in numerical procedures and computational performance. In particular, these localized behaviors need for extremely fine descriptions, and this has an associated impact in the number of degrees of freedom from one side, and the decrease of the time step employed in usual explicit time integrations, whose stability scales with the size of the smallest element involved in the mesh. In the present work we propose a data-driven technique for learning the rich behavior of a local patch and integrate it into a standard coarser description at the structure level. Thus, localized behaviors impact the global structural response without needing an explicit description of that fine scale behaviors.

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