Outrigger Design for High-Rise Buildings

Choi, Hi Sun; Ho, Goman; Joseph, Leonard M.; Mathias, Neville; Ctbuh,

doi:10.1201/9781315661971

Cited by 27 publications

(7 citation statements)

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“…Closely spaced ties in columns and walls posed a challenge to the placement of the high strength 10 ksi concrete needed for this project” (p. 325). Descriptions and technical details of an outrigger system are found in Choi et al (2012) and Taranath (2010). Dual core shear wall and outrigger frame structural systems are being increasingly applied in the design of tall reinforced concrete buildings.…”

Section: The Buildingmentioning

confidence: 99%

Responses of a 58-Story RC Dual Core Shear Wall and Outrigger Frame Building Inferred from Two Earthquakes

Çelebi

2016

Earthquake Spectra

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Responses of a dual core shear-wall and outrigger framed 58-story building recorded during Mw6.0 Napa earthquake of August 24, 2014 and Mw3.8 Berkeley earthquake of 20 October 2011 are used to identify its dynamic characteristics and behavior. Fundamental frequencies are 0.28 Hz (NS), 0.25 Hz (EW) and 0.43 Hz (torsional). Rigid body motions due to rocking are not significant. Average drift ratios are small. Outrigger frames do not affect average drift ratios or mode shapes. Local site effects do not affect the response; however, response associated with deeper structure may be substantial. A beating effect is observed from data of both earthquakes but beating periods are not consistent.Low critical damping ratios may have contributed to the beating effect. Torsion is relatively larger above outriggers as indicated by the time-histories of motions at the roof, possibly due to the discontinuity of the stiffer shear walls above level 47.

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Section: The Buildingmentioning

confidence: 99%

Responses of a 58-Story RC Dual Core Shear Wall and Outrigger Frame Building Inferred from Two Earthquakes

Çelebi

2016

Earthquake Spectra

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“…Numerous studies have concentrated on identifying the optimal outrigger position for frame‐core tubes with outrigger structures. Generally, the optimal location for a single outrigger structure is situated between 0.5 and 0.8 times the building height 1 . In this study, the investigation delves into the alteration patterns governing the optimal outrigger position (minimizing vertex displacement) for the outrigger structure, considering the impact of ordinary floor stiffness.…”

Section: Parameter Optimizationmentioning

confidence: 99%

“…Taller buildings are continually being constructed due to the increasing urban population density and ongoing social and economic development. Super‐high‐rise structures incorporating outriggers are now extensively employed due to their high lateral resistance 1 . In this structural system, mega beams or trusses are incorporated on equipment floors or refuge levels to connect the core tube with the perimeter columns.…”

Section: Introductionmentioning

confidence: 99%

Improved analytic method for outrigger structures considering floor stiffness

Chen,

Tan,

Zhao

et al. 2023

Structural Design Tall Build

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SummaryCurrent analytical models for outrigger structures in super high‐rise buildings tend to oversimplify by not considering the stiffness of individual floors. This paper introduces a more refined calculation model, based on the substructure method, which takes floor stiffness into account. To verify our proposed approach, we derived a mathematical algorithm and developed a finite element model using ANSYS. When compared to traditional methods that only account for outrigger stiffness, our model, which incorporates both outrigger and floor stiffness, provides improved accuracy in calculating vertex displacement. It also suggests an upward shift in the optimal position for the outrigger and bolsters the overall building's lateral stiffness. To further our analysis, we introduced an equivalent stiffness calculation formula, using the Bayesian parameter estimation method. When applied to dynamic analysis, this formula aligns closely with the results from the finite element simulations. Furthermore, the suggested algorithm for determining the best position for the outrigger is consistent with theoretical calculations. By considering the contribution of regular floors to the overall structure, we found that the fitted equivalent core tube stiffness offers a reliable reflection of structural stiffness. Lastly, when this equivalent stiffness was applied to a dynamic analysis based on Rayleigh's energy method, there was a noticeable reduction in computational effort. This yields not only more efficient calculations but also precise results, rendering it particularly valuable during the initial design phases of high‐rise buildings.

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“…(3) Damping outriggers need to be installed in the equipment floors without rigid outriggers, since megastructures need rigid outriggers to strengthen the lateral stiffness. Because the outriggers occupy the floor space and the dampers need overhauling, and considering the architectural space availability, the outriggers are usually located in the mechanical floors and refuge floors only [29]. One or two dampers can be connected at the end of each outrigger.…”

Section: Influence Of the Wall Bending Stiffness On The Modementioning

confidence: 99%

Optimal Design of Mega‐Frame Core Wall Structures Equipped with Viscous Damped Outriggers for Human Comfort Performance under Wind Loading

Yang

Zhao

Shi

et al. 2021

Shock and Vibration

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Megatall and supertall buildings often adopt megastructure systems characterized by secondary structure systems, and the serviceability problem caused by wind-induced vibrations often becomes the dominant factor in the structural design. Because the deformation of a supertall building usually presents bending characteristics, a viscous damped outrigger can reduce the wind-induced vibration of a supertall building with the installation of a small number of viscous dampers. However, time history analysis of the prototype model considering the nonlinear characteristics of viscous dampers is time-consuming, which is not conducive for iterative design optimization. Additionally, the conventional simplified model composed of one cantilever beam cannot be used for the analysis and design of a viscous damped outrigger. In this study, a simplified wind-induced vibration prediction model is proposed based on the mechanical characteristics of megastructures. This simplified model is a plane model that includes both core walls and frames whose member size can be extracted from the original structure. Parametric analysis shows that the simplified model has high acceleration prediction accuracy. An optimal design method combined with the simplified model, which aims to minimize the damped outrigger system cost, is proposed. A 600-m supertall building is presented as a case study. The accuracy and effectiveness of the simplified model and the optimal design method proposed in this study are illustrated. Thus, applying this optimal design method in combination with the simplified model can save significant analysis and design time and is conducive to the application of viscous damped outriggers in practical engineering.

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Outrigger Design for High-Rise Buildings

Cited by 27 publications

References 0 publications

Responses of a 58-Story RC Dual Core Shear Wall and Outrigger Frame Building Inferred from Two Earthquakes

Responses of a 58-Story RC Dual Core Shear Wall and Outrigger Frame Building Inferred from Two Earthquakes

Improved analytic method for outrigger structures considering floor stiffness

Optimal Design of Mega‐Frame Core Wall Structures Equipped with Viscous Damped Outriggers for Human Comfort Performance under Wind Loading

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