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In this paper, the performance of a super-tall tower is evaluated through Milad Tower in Tehran, Iran, as a case study. The structure is a 435 meters tall telecommunication tower and is structurally studied in this paper. For this purpose, linear endurance time (ET) method and time history (TH) analysis are used to compare the results and focus on the structure's dynamic properties and behavior. The analyses are performed on a finite element model with SAP2000 and Abaqus software. Assumptions in linear modeling are investigated, including shell or solid element type and mesh sizing. Furthermore, the model is verified with experimental modal data. Performance-based analysis is performed according to ASCE41; the tower's behavior and strength capacity is evaluated for different tower elevations. The scaling method effect on the response of the structure is demonstrated to have a major role. The Endurance Time method as a simplified and alternative analysis tool is exerted to estimate the structure's significant responses and compared to ground motions with different spectrums. Results show that the ET method can adequately estimate the results in comparison with the TH method.

SummaryDiagrid system is known for its efficient structural behavior besides its outstanding aesthetic characteristics and architectural flexibility. However, a brief existing study on the nonlinear performance of the diagrid system has reported an inefficient nonlinear behavior. Diagrid with fused‐shear link is a newly introduced system that can solve this flaw in the conventional diagrids and keep the advantages as well. In this paper, this newly introduced system is called eccentric diagrid system (EDS). Benefits of the EDS are presented, and a series of nonlinear pushover and time history analyses are conducted to compare EDS with the conventional diagrid system (CDS). In this manner, three different configurations for both EDS and CDS with diagrid angles of 45°, 63.4°, and 71.6° are chosen for two different 12‐ and 18‐story buildings. The models are designed based on an R‐factor equal to 3.6 and 5 for CDS and EDS frames, respectively. Then, the assumed R‐factor for EDS is verified according to Federal Emergency Management Agency P695, and the priority of members yielding is spotted. The results show that EDS can effectively enhance the post‐yield performance and seismic characteristics of the structure relative to CDS, including ductility and overstrength ratio more than 2.5 and 1.3 times, respectively.

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