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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
International Journal of High-Rise Buildings
Journal Basic Information
Journal DOI :
Council on Tall Building and Urban Habitat Korea
Editor in Chief :
Volume & Issues
Volume 5, Issue 3 - Sep 2016
Volume 5, Issue 2 - Jun 2016
Volume 5, Issue 1 - Mar 2016
Selecting the target year
Wilshire Grand: Outrigger Designs and Details for a Highly Seismic Site
Joseph, Leonard M. ; Gulec, C. Kerem ; Schwaiger, Justin M. ;
International Journal of High-Rise Buildings, volume 5, issue 1, 2016, Pages 1~12
DOI : 10.21022/IJHRB.2016.5.1.1
The 1100 foot [335 m] tall Wilshire Grand Center tower under construction in Los Angeles illustrates many key outrigger issues. The tower has a long, narrow floor plan and slender central core. Outrigger braces at three groups of levels in the tower help provide for occupant comfort during windy conditions as well as safety during earthquakes. Because outrigger systems are outside the scope of prescriptive code provisions, Performance Based Design (PBD) using Nonlinear Response History Analysis (NRHA) demonstrated acceptability to the Los Angeles building department and its peer review panel. Buckling Restrained Brace (BRB) diagonals are used at all outrigger levels to provide stable cyclic nonlinear behavior and to limit forces generated at columns, connections and core walls. Each diagonal at the lowest set of outriggers includes four individual BRBs to provide exceptional capacities. The middle outriggers have an unusual 'X-braced Vierendeel' configuration to provide clear hotel corridors. The top outriggers are pre-loaded by jacks to address long-term differential shortening between the concrete core and concrete-filled steel perimeter box columns. The outrigger connection details are complex in order to handle large forces and deformations, but were developed with contractor input to enable practical construction.
Outrigger Systems for Structural Design of Complex-Shaped Tall Buildings
Moon, Kyoung Sun ;
International Journal of High-Rise Buildings, volume 5, issue 1, 2016, Pages 13~20
DOI : 10.21022/IJHRB.2016.5.1.13
Today's architecture can be best understood only through the recognition of pluralism, and, as is true of other building types, multiple design directions are prevalent for tall buildings. This contemporary design trend has produced many complex-shaped tall buildings, such as twisted, tilted and tapered form towers. Among many different structural systems developed for tall buildings, the outrigger system, with its inherent structural efficiency and flexibility in façade design, is widely used for contemporary tall buildings. This paper studies structural performance of outrigger systems employed for complex-shaped tall buildings. Twisted, tilted and tapered tall buildings are designed with outrigger structures, and their structural performance is investigated. For the twisted outrigger study, the buildings are twisted up to 3 degrees per floor. In the tilted outrigger study, the angles of tilting range from 0 to 13 degrees. The impact of eccentricity is investigated for gravity as well as lateral loads in tilted towers. In the study of tapered outrigger structures, the angles of tapering range from 0 to 3 degrees. Parametric structural models are generated using appropriate computer programs for these studies, and the models are exported to structural engineering software for design and analyses.
The Evolution of Outrigger System in Tall Buildings
Ho, Goman W.M. ;
International Journal of High-Rise Buildings, volume 5, issue 1, 2016, Pages 21~30
DOI : 10.21022/IJHRB.2016.5.1.21
The structural efficiency of tall buildings heavily depends on the lateral stiffness and resistance capacity. Among those structural systems for tall buildings, outrigger system is one of the most common and efficient systems especially for those with relatively regular floor plan. The use of outriggers in building structures can be traced back from early 50 from the concept of deep beams. With the rise of building height, deep beams become concrete walls or now in a form of at least one story high steel truss type of outriggers. Because of the widened choice in material to be adopted in outriggers, the form and even the objective of using outrigger system is also changing. In the past, outrigger systems is only used to provide additional stiffness to reduce drift and deflection. New applications for outrigger systems now move to provide additional damping to reduce wind load and acceleration, and also could be used as structural fuse to protect the building under a severe earthquake condition. Besides analysis and member design, construction issue of outrigger systems is somehow cannot be separated. Axial shortening effect between core and perimeter structure is unavoidable. This paper presents a state-of-the-art review on the outrigger system in tall buildings including development history and applications of outrigger systems in tall buildings. The concept of outrigger system, optimum topology, and design and construction consideration will also be discussed and presented.
The Use of Bracing Systems with MR Dampers in Super Tall Buildings
Aly, Aly Mousaad ;
International Journal of High-Rise Buildings, volume 5, issue 1, 2016, Pages 31~41
DOI : 10.21022/IJHRB.2016.5.1.31
High-rise buildings are increasingly viewed as having both technical and economic advantages, especially in areas of high population density. Increasingly taller buildings are being built worldwide. Increased heights entail increasing flexibility, which can result in serviceability problems associated with significant displacements and accelerations at higher floors. The purpose of this paper is to present the concept of a versatile vibration control technology (MR dampers with bracings) that can be used in super tall buildings. The proposed technology is shown to be effective, from a serviceability point of view, as well as resulting in dramatically reduced design wind loads, thus creating more resilient and sustainable buildings.
High-rise Reinforced-concrete Building Incorporating an Oil Damper in an Outrigger Frame and Its Vibration Analysis
Omika, Yukihiro ; Koshika, Norihide ; Yamamoto, Yukimasa ; Kawano, Kenichi ; Shimizu, Kan ;
International Journal of High-Rise Buildings, volume 5, issue 1, 2016, Pages 43~50
DOI : 10.21022/IJHRB.2016.5.1.43
The reinforced-concrete multi-story shear-wall structure, which can free a building from beams and columns to allow the planning of a vast room, has increasingly been used in Japan as a high-rise reinforced-concrete structure. Since this structural system concentrates the seismic force onto multi-story shear walls inside, the bending deformation of the walls may cause excessive deformation on the upper floors during an earthquake. However, it is possible to control the bending deformation to within a certain level by setting high-strength and rigid beams (outriggers) at the top of the multi-story shear walls; these outriggers restrain the bending behavior of the walls. Moreover, it is possible to achieve high energy dissipation by placing vibration control devices on the outriggers and thus restrain the bending behavior. This paper outlines the earthquake response analysis of a high-rise residential tower to demonstrate the effectiveness of the outrigger frame incorporating vibration control devices.
Mechanical Amplification of Relative Movements in Damped Outriggers for Wind and Seismic Response Mitigation
Mathias, Neville ; Ranaudo, Francesco ; Sarkisian, Mark ;
International Journal of High-Rise Buildings, volume 5, issue 1, 2016, Pages 51~62
DOI : 10.21022/IJHRB.2016.5.1.51
The concept of introducing viscous damping devices between outriggers and perimeter columns in tall buildings to provide supplementary damping and improve performance, reduce structural costs, and increase available usable area was developed and implemented by Smith and Willford (2007). It was recognized that the relative vertical movement that would occur between the ends of outriggers and columns, if they were not connected, could be used to generate damping. The movements, and correspondingly damping, can potentially be significantly increased by amplifying them using simple "mechanisms". The mechanisms also make it possible to increase the number of available dampers and thus further increase supplementary damping. The feasibility of mechanisms to amplify supplementary damping and enhance structural performance of tall, slender buildings is studied with particular focus on its efficacy in improving structural performance in wind loads.
The Damped Outrigger - Design and Implementation
Smith, Rob ;
International Journal of High-Rise Buildings, volume 5, issue 1, 2016, Pages 63~70
DOI : 10.21022/IJHRB.2016.5.1.63
The use of outriggers with dampers (the damped outrigger concept) has been shown to be a cost effective method of adding structural damping to a high rise building, and has been described in previous work by the author. This paper further develops the methods used to design such systems and highlights lessons learned in their application. This includes calculation methods, a review of subsequent research from others, and discussions regarding code-compliance.