The Structural Design of Tall and Special Buildings

Liu, Jun; Song, Bohan; Wu, Guilong; Luo, Xiaoqun; Zhang, Qilin; Yu, Guijing

doi: 10.1002/tal.2090pmid: N/A

The mechanical characteristics of the setback super‐tall structure are complex, and the design is difficult. In the actual analysis and design process, the relevant influencing factors should be fully considered. In this paper, the fine construction simulation analysis of the super‐tall structure is carried out. Based on the shrinkage test of concrete members, the CEB‐FIP 90 shrinkage model is modified in terms of the parameters of cross‐section shape and size. The modified model is used to calculate the shrinkage strain of concrete, and the influence of uneven settlement of foundation and seasonal temperature on the structure is considered in the construction simulation analysis. The influence proportion of each non‐load effect on the horizontal displacement, vertical displacement, and internal force of key components is obtained. The refined construction analysis results are compared with the field monitoring data, and the data are in good agreement.

Jia, Chuanguo; Li, Yutao; Su, Hongchen; Gan, Min; Chen, Longchang; Guo, Weinan

doi: 10.1002/tal.2078pmid: N/A

In seismic response analysis of seismically isolated structures (SISs), the nonlinearity is concentrated in the isolation layer while the upper structure behaves linearly, making SISs locally nonlinear systems. This paper proposed a novel seismic analysis method based on equivalent linearization (EL) and iterative solution for SISs. In this method, the equilibrium equations of an SIS are expressed by the second‐order ordinary differential equations of the structural system as well as the hysteretic force of seismic isolation bearings (SIBs). Based on EL theory, the linearized equilibrium equations of the overall system were reconstructed in which the EL parameters are derived theoretically. The inter‐history iteration (IHI) method was proposed to solve the linearized equation system and calculate the EL parameters in sequence iteratively for seismic response analysis of SISs, thus reducing computational cost without excessive loss of accuracy. In addition, the secondary development of the proposed method was programmed in ABAQUS for ease of engineering applications. Finally, the convergence and accuracy of the method were investigated through numerical simulation of an SIS case study. As the numerical investigation indicates, the proposed method considers the coupling between structural response and the EL parameters, achieving a high convergence rate and satisfactory solution accuracy. The ABAQUS secondary development program utilizes the powerful pre‐processor, post‐processor, and solvers of ABAQUS, making the IHI method more appropriate for engineering applications.

John, Neethu Elizabeth; Kamath, Kiran

doi: 10.1002/tal.2080pmid: N/A

Outriggers are internal structural systems used to enhance the stiffness and strength of high‐rise structures. This research investigates the efficacy of a hybrid outrigger system (HOS) which consists of one conventional and one virtual outrigger at two distinct floor levels in high‐rise RCC buildings. A non‐dimensional quantity, ϒ, defined as the relative stiffness ratio between the core and the diaphragm is used to describe variations in the stiffness of the building's core, stiffness of floor diaphragm, breadth, and height of the structure, in the behavioral analysis of the HOS. To investigate the efficacy and optimum locations of the hybrid outriggers, static and dynamic analysis are carried out on models with four‐story heights of 140, 210, 280, and 350 m under static wind loading, uniform wind loading, equivalent static earthquake loading, and dynamic earthquake loading. Results are assessed based on the responses from roof displacement (Disptop), base bending moment, roof acceleration (Acctop), fundamental period, and absolute maximum inter‐story drift ratio (ISDabs.max). Based on the minimum responses of the aforementioned dependent parameters under wind and earthquake excitations, the corresponding optimum locations of hybrid outriggers are investigated. To investigate the impact of the slab on the functionality of the HOS, the behavior of shell stress variation in the tension and compression side of the slab at the outrigger floor level and the force transmission through the column at the outrigger level is analyzed. Also, the optimum location of the hybrid outriggers based on the ideal performance index (IdealPI) is investigated. IdealPI is defined as a parameter that considers the combined response of Disptop, Acctop, and ISDabs.max and the criteria required for the structure under wind and seismic loads. From the behavioral analysis results, it is found that an increase in the stiffness of the slab showed an improved performance of the HOS compared to an increase in the stiffness of the core, and HOS performance can be maximized by increasing both thickness of the slab and outrigger arm length. The findings of the optimum location analysis could serve as a guide for structural engineers when selecting suitable positions for hybrid outriggers in high‐rise structures.

doi: 10.1002/tal.2023pmid: N/A

No abstract is available for this article.

Aggarwal, Yati; Kulariya, Mahipal; Saha, Sandip Kumar

doi: 10.1002/tal.2086pmid: N/A

The present study investigates the effect of earthquake sequences on the response of reinforced concrete hilly buildings having typical configurations, that is, stepback and split‐foundation, with three different story ratios. A set of 30 as‐recorded mainshock‐aftershock sequence of earthquake ground motions is considered for this study. Mainshock acceleration time histories are scaled at two distinct intensity levels to obtain the mainshock‐damaged building. These mainshock‐damaged hilly buildings are then subjected to aftershocks. A comparative study is performed for various response quantities, such as peak interstory drift ratio, peak floor acceleration, and peak roof displacement of undamaged and mainshock‐damaged buildings under aftershocks. Further, fragility analysis is carried out to study the effect of aftershocks on undamaged and mainshock‐damaged hilly buildings. Subsequently, component‐wise seismic loss estimation due to damage in the non‐structural and structural components is performed. It is concluded from the study that the building components that contribute maximum to the expected repair cost ratio vary with respect to the intensity of the aftershocks. Also, the estimated seismic loss is higher in mainshock‐damaged split‐foundation buildings in comparison to stepback buildings.