The Structural Design of Tall and Special Buildings

He, Liusheng; Wang, Yong; Liu, Yuan; Yu, Xiyang; Bai, Yongtao

doi: 10.1002/tal.1916pmid: N/A

To study the effect of plan irregularity on the collapse performance of reinforced concrete (RC) moment frame structures, three groups of seven‐story RC frame structures with different plan layout, one rectangular and two L‐shaped with different dimensions, were designed and numerically studied. The length‐to‐width ratio, protrusion ratio (length of protruding part divided by the total length), and the length‐to‐width ratio of the protruding part were selected as the study parameters. The fragility curves for the collapse limit state of each structure were generated through incremental dynamic analysis, and the collapse margin ratios of the structures were derived. It is found that the seismic collapse performance of the structure with the rectangular plan is significantly affected by the length‐to‐width ratio, and setting a threshold value of 6 is reasonable. For the L‐shaped structure, the influence of the protrusion ratio and the length‐to‐width ratio of the protruding part on the average collapse resistance capacity is not significant. A larger value increases the collapse resistance under rare earthquake. Effect of setting seismic joint in the L‐shaped structure is also studied, and the results indicate that setting the seismic joint or not hardly influences its seismic collapse performance.

Huang, Dongming; Liu, Zhenzhen; Lu, Yiyan; Yan, Bo

doi: 10.1002/tal.1917pmid: N/A

Concrete‐filled square steel tube (CFSST) stub columns are vital to structural engineering owing to their excellent mechanical properties and architectural benefits. In this study, 42 steel‐fiber‐reinforced CFSST stub columns with different variables are designed to investigate their eccentric compression performance. The variables include the eccentricity ratio (0.08, 0.20, and 0.32), steel fiber volume content (0.0%, 0.6%, 1.2%, and 1.8%), concrete strength (40, 50, and 60 MPa), and square steel tube thickness (3, 3.75, and 4.5 mm). The failure mode, load–lateral deformation characteristics, load–bending moment interaction relationship, and relative load–strain response are investigated experimentally. It is discovered that the use of steel fibers can increase the bearing capacity and improve the ductility of CFSST stub columns. The ABAQUS software is applied to establish and calculate finite element models, and the results of which are consistent with the experimental results. Moreover, a simplified formula to calculate the eccentric ultimate bearing capacity of CFSST stub columns is derived. Under a certain safety margin, the predicted results agree well with the experimental results.

Kord, Sadeq; Taghikhany, Touraj

doi: 10.1002/tal.1915pmid: N/A

Large‐scale structures are subjected to environmental loads or frequent seismic motion with irremediable effect. These loads have often multidirectional actions on structures, and it couples their responses and leads to multiple‐input multiple‐output (MIMO) problem. The complexity of MIMO model and the relative time‐delays in sensing networks are among major sources of error in dynamic properties identification in large scale structures. This study proposed a parametric‐time domain method to reduce the negative effect of these problems. For this purpose, the contribution of each input in the output signals is determined using QR decomposition and converts a MIMO problem into multiple single‐input multiple‐output (SIMO) ones. In this regard, an Autoregressive Moving Average with eXogenous (ARMAX) model is implemented on decoupled signals for modal identification. Further, for time synchronization of records, a cross‐correlation function has been used to achieve more precise results. The method was employed real strong‐motion response recorded by different sensors at a high rise 64‐story concrete building. Results demonstrate the promising precision of the proposed algorithm for identifying current structural modal properties under real earthquake excitations. Hence, structures can be monitored efficiently along seismic experiences to detect any possible variations in their structural features. The comparison between the output of the proposed method and previous study indicates a considerable improvement on accuracy of the estimated model property particularly on mode shapes.

doi: 10.1002/tal.1868pmid: N/A

No abstract is available for this article.

Shan, Jiazeng; Jiang, Zhi; Wu, Weichao; Shi, Zhiguo

doi: 10.1002/tal.1918pmid: N/A

This study presents a designed framework of structural monitoring for coupled shear wall structures by integrating a theoretical response estimation model and a prototype micro‐voltage sensing module. Inspired by the deformation mode of coupled shear walls, a supplemental self‐sensing component is proposed for predicting the target flexural deformation. The self‐sensing component is designed to include permanent magnets and cross wires and installed parallel to the coupling beam. The relative velocity between the two attached walls is obtained using electromagnetic (EM) induction and measured micro‐voltages. Accordingly, the theoretical principle of the self‐sensing prediction model is then derived, and the calculation flowchart is presented. Illustratively, a detailed finite element model was performed in ABAQUS to investigate the feasibility and robustness of the proposed self‐sensing model under different excitation scenarios, and a parametric study is performed. Then, the nonstationary excitation is adopted to further investigate the performance of the self‐sensing model. Furthermore, an EM‐based sensing module for low‐level velocity measurement is developed and the prototype is tested by utilizing a shaking table test with satisfactory performance.