Development and application of a simplified model for the design of a super-tall mega-braced frame-core tube building

Abstract

Abstract:Resilience-based earthquake design for next-generation super-tall buildings has become an important trend in earthquake engineering. Due to the complex structural system in super-tall buildings and the extreme computational workload produced when using refined finite element (FE) models to design such buildings, it is rather difficult to efficiently perform a comparison of different design schemes of super-tall buildings and to investigate the advantages and disadvantages of different designs. Here, a simplified nonlinear model is developed and applied to compare two design schemes (the fully braced scheme and half-braced scheme) of a super-tall mega-braced frame-core tube building, which is an actual engineering project with a total height of approximately 540 m. The accuracy of the simplified model is validated through a comparison of the results of modal analyses, static analyses, and dynamic time history analyses using the refined FE models. Subsequently, the plastic energy dissipation of different components and the distribution of the total plastic energy dissipation over the height of the two design schemes are compared using the proposed simplified model. The analyses indicate that the fully braced scheme is superior because of its more uniform energy distribution along the building height and the large amount of energy dissipated in the replaceable coupling beams, which enables rapid repair and re-occupancy after an earthquake. In contrast, the potential damage in the half-braced scheme is more concentrated and more severe, and the damage in the core tubes is difficult to repair after an earthquake.

Optimal multi‐type sensor placement for monitoring high‐rise buildings under bidirectional long‐period ground motions

“…With rapid urbanization and fast‐growing population, an increasing number of super high‐rise buildings with complex configurations and innovative structural systems have been built in megacities around the world . Although most of the skyscrapers are located in cities with low or moderate seismicity, such as Dubai, Shanghai, Shenzhen, and Hong Kong to name a few, recent studies revealed that long‐period ground motions from distant large‐magnitude earthquakes could cause great impact on the safety and functionality of high‐rise buildings .…”

“…The condensed building model inevitably neglects the details of the real building structure, such as the coupling beams in shear walls and the connections between the outrigger trusses and the mega columns. It is almost impossible for the condensed model to include these details, but they are often seismic vulnerable for super high‐rise buildings under long‐period ground motions . Thus, the condensed building model may not be adequate for the seismic assessment of high‐rise buildings under long‐period ground motions.…”

Open and closed shear-walls in high-rise structural systems: Static and dynamic analysis

“…Eventually, the displacement components δ t and w can be easily derived from Equations (22) and (26).…”

“…Moreover, other simplified methods can be applied in cases where the vertical stiffening structures are constituted by frames [22,23], or by open shear walls [24]. In the literature there are also simplified methods for the dynamic analysis of tall buildings that involve the use of analytical [25,26] or FE models [27].…”

Experimental study and finite element analysis of energy dissipating outriggers

“…Li and Wu (2004), Poon et al (2011), Jiang et al(2014) and Lu et al (2011Lu et al ( , 2013Lu et al ( , 2014Lu et al ( , 2016 found that the outriggers could dissipate a great deal of the seismic energy after yielding, which would significantly influence the nonlinear seismic responses of buildings. Moehle (2015) indicated that the outriggers could be designed to yield and fail as "fuses" of the building, to dissipate the seismic energy and to protect the primary structure.…”