Experimental study and finite element analysis of energy dissipating outriggers

Abstract

The outriggers are widely adopted in tall and super-tall buildings. Their energy dissipation capacity can significantly influence the nonlinear seismic responses of the entire building structure. Based on an actual tall building project, the structural responses and energy dissipation capacities of three different outriggers were studied through experiments and finite element analyses. The test results of conventional outrigger specimen showed a steep deterioration after peak strength and an unfavorable energy dissipation capacity due to the global buckling of the braces and the local buckling of the chords after flexural yielding. By using buckling restrained braces (BRBs) and reduced beam sections (RBSs) in a new design of outriggers, the energy dissipation capacity and the ductility of outriggers were significantly improved. The yield and peak strengths were further improved with the use of high strength steel in chords on a third specimen. The finite element (FE) simulation of the three specimens indicated that the initial imperfection of the specimens shall be considered, and the developed FE models yielded good agreements with the test results. The outcome of this work can provide additional references for the application of outriggers in tall buildings.

Dual-Objective Control of Maximum and Residual Drift Ratios of Super-Tall Buildings Based on Self-Centering Energy Dissipation Outriggers

“…Currently, high-performance concrete and steel are adopted to design and construct vertical components in super-tall buildings to improve the deformation limits corresponding to each damage stage and then alleviate the damage to the main structure under the same deformation (Nehdi, 2013;Liew et al, 2016;Hassan et al, 2017;Zhang et al, 2020). Regarding the horizontal components (e.g., coupling beam and outrigger), highperformance energy dissipation components can be introduced to dissipate plastic energy, and reduce damage to the vertical components to ensure the seismic performance of the main structure (Yang et al, 2016;Ding et al, 2018). Frame-core tube-outrigger systems, which are typical hybrid lateral loadresisting systems, and have been widely used in modern super-tall buildings (Park and Oh, 2018;Zhang et al, 2018;Shim et al, 2019;Alhaddad et al, 2020;Huang et al, 2021).…”

Development of a novel sacrificial‐energy dissipation outrigger system for tall buildings

“…The dynamic characteristics of the structures equipped with outriggers were correlated from field measurement and numerical models . The seismic performances of outriggers have been experimentally studied, and the corresponding finite‐element (FE) models were validated with the experimental results . In addition, the damped‐outrigger system has achieved significant progress recently …”

“…Yang et al performed experimental and numerical studies on energy‐dissipating outriggers. Their research identified that, owing to the global buckling of the inclined braces and the local buckling of the chords, conventional outriggers have limited deformation and energy‐dissipating capacities.…”

“…8,9 The seismic performances of outriggers have been experimentally studied, and the corresponding finite-element (FE) models were validated with the experimental results. [10][11][12] In addition, the damped-outrigger system has achieved significant progress recently. [13][14][15][16][17][18][19] Existing studies identified that when a tall building is subjected to the action of a service-level earthquake (SLE, ie, 63% probability of exceedance in 50 y) or the action of a design-based earthquake (DBE, ie, 10% probability of exceedance in 50 y), the outrigger should remain elastic to reduce the structural deformation and control the damage to the structural and nonstructural components.…”

Optimal vertical configuration of combined energy dissipation outriggers

“…Moreover, experimental tests have also been performed on outriggers with BRBs. Yang et al tested three 1/3‐scaled steel truss outrigger specimens: one conventional outrigger specimen and two BRB‐outrigger specimens, which used reduced beam section connections for the chords of the steel truss. The test results revealed that outriggers specimens that incorporated BRBs had superior energy dissipation capacity and ductility than the conventional outrigger specimen.…”