The Structural Design of Tall and Special Buildings

Nzabonimpa, J. D.; Hong, Won‐Kee; Kim, Jisoon

doi: 10.1002/tal.1391pmid: N/A

The aim of this study is to develop laminated metal plates for a moment connection of the precast concrete columns. Metal plates were proposed as a time‐ and cost‐saving alternative to conventional monolithic cast‐in‐place joints for connecting precast concrete frames. This study investigated the possibility of using mechanical joints for the connections of both steel‐concrete composite precast frames and reinforced concrete precast frames. A full erection test of precast columns connected with laminated metal plates was performed to demonstrate the efficiency and simplicity of the proposed method. It was shown that the use of the novel mechanical joints with steel plates significantly reduces construction time compared with the conventional monolithic assembly. The total precast column assembly time was approximately 10–20 min, eliminating pour forms and curing times required for the conventional concrete frames. This study also presents an analytical modeling of the proposed connection for multibay precast frames to explore the strains and stress exerted on the joints.

Hosseinzadeh, Leila; Emami, Fereshteh; Mofid, Masood

doi: 10.1002/tal.1390pmid: N/A

Studies on corrugated steel shear walls (CSSWs) generally indicate noticeable increase of energy absorption, as well as increasing shear buckling capacity of corrugated plates being more likely rather than the flat plates. In this paper, the effect of variation in the angle of trapezoidal plate on the behavior of CSSWs has extensively been investigated. Three specimens of CSSW with 1 story and single bay in half scale are tested under cyclic load. The observations of experiment do indicate that stress concentration has been increased in the corner of subpanels, by increasing of the corrugation angle. Development of the tensile field and wall yield and damage depends on the geometry of the plate. By increasing the corrugation angle, the stiffness and energy dissipation decrease; in addition, large loss of strength takes place. Comparing the numerical and experimental results indicates that for a closer look at behavior of trapezoidal CSSWs, fracture mechanics, fatigue, and damping of materials should be considered by numerical analysis.

doi: 10.1002/tal.1331pmid: N/A

No abstract is available for this article.

Lu, Zheng; He, Xiangdong; Zhou, Ying

doi: 10.1002/tal.1392pmid: N/A

This paper presents 2 models to simulate the damping behavior of a 12‐story vertically mixed structure with upper steel and lower concrete substructures (S/RC structure). One is the modal strain energy damping model based on modal damping ratio. The other is the assembled Rayleigh damping model based on damping matrix that is obtained by combining Rayleigh damping matrix of steel components with that of concrete ones. Then a 12‐story S/RC frame and a 12‐story RC frame are designed and used for shaking table test. Based on the test, the expressions for the damping behavior of steel and concrete substructures of the S/RC frame are derived, and these expressions are utilized to form 2 different damping models of the S/RC structure separately. By comparing the damping behavior of the 2 models in analysis with what has been identified in the tests, the feasibility of the 2 models are assessed in both frequency domain and time domain. Theoretical analysis and experimental results show that the assembled Rayleigh damping model is not applicable to conventional modal analysis because of its nonproportional characteristics. However, the modal strain energy damping model based on equivalence of the dissipated modal strain energy of structure, which embodies the essence of damping, can give better predictions on damping behavior of the S/RC frame in both time and frequency domains. Finally, some suggestions are put forward on the selection of damping parameters in practical seismic design for vertically mixed structures.

Zhang, J.W.; Li, Q.S.

doi: 10.1002/tal.1385pmid: N/A

Ping An Finance Center with a height of 600 m and 118 storeys, located in Shenzhen, is currently the second tallest building in China. This paper presents a comprehensive study of wind effects on the supertall building through wind tunnel testing and field measurement. The wind‐induced loads and pressures on the skyscraper were measured by high‐frequency force balance technique and synchronous multipressure sensing system, respectively. In the wind tunnel study, a whole range of characteristic properties, including mean and r.m.s force coefficients, power spectral densities, coherences, correlations, and phase‐plane trajectories, wind‐induced displacement, and acceleration responses were presented and discussed. In addition, a field measurement study of the dynamic responses of Ping An Finance Center was conducted during a tropical cyclone, which aimed to verify the design assumptions and further the understanding of the dynamic properties and performance of the 600‐m‐high supertall building, including natural frequencies, damping ratios, and wind‐induced structural responses. Then, the serviceability of the skyscraper is assessed on the basis of the experimental results and field measurements. The outcomes of this combined model test and field measurement study are expected to be useful for the wind‐resistant design of future supertall buildings.

Ma, Xingliang; Xu, Fuyou

doi: 10.1002/tal.1386pmid: N/A

A vast quantity of measurements of wind‐induced non‐Gaussian effects on buildings call for the burgeoning development of more advanced extrema estimation approaches for non‐Gaussian processes. In this study, a well‐directed method for estimating the peak factor and modeling the extrema distribution for non‐Gaussian processes is proposed. This method is characterized by using two fitted probability distributions of the parent non‐Gaussian process to separately fulfill the estimations of the extrema on long‐tail and short‐tail sides. In this method, the Johnson transformation is adopted to be the probabilistic model for fitting the parent distribution of the non‐Gaussian process due to its superior fitting goodness and universality. For each dataset, two Johnson transformations will be established by two parameter estimation methods to individually estimate the extrema on two sides. Then a Gumbel assumption is applied for conveniently determining the non‐Gaussian peak factor. This method is validated through long‐duration wind pressure records measured on the model surfaces of a high‐rise building in wind tunnel test. The results show that the proposed method is more accurate and robust than many existing ones in estimating peak factors for non‐Gaussian wind pressures.

Tao, Qian; He, Zheng

doi: 10.1002/tal.1389pmid: N/A

The correlation between the performance of some commonly used linear system solvers and the characteristics of system matrices, especially in the time history analysis of supertall buildings, is comprehensively identified. Relying on 5 well‐designed structural models with height varying from 47 to 660 m, the supernodal LLT solver and the conjugate gradient (CG) solver with the factorized sparse approximate inverse preconditioner are selected due to their actual efficiency. More importantly, basing on 90 fictitious supertall structural models generated from the parameterized method, the effects of structural characteristics on solver performance and the corresponding mechanism are studied by 3 mathematical indexes with parameters come from the equivalent dynamic stiffness matrices. Impacts of processors on the solvers are also clarified by associating the architectural characteristics of processors with the indexes. The performance of the 2 solvers is affected globally with increasing building size; different variation laws are shown for different structural systems. However, the accuracy of the CG solver does not exhibit distinct variation due to a slight change in the 2‐norm condition number of the matrices. The CG solver is found to be more applicable on GPU processor than the LLT solver due to its smaller gap between computational workload and the amount of data transferred.

Ye, Zhihang; Wu, Gang

doi: 10.1002/tal.1387pmid: N/A

A major type of mega‐substructure system is yet to fulfill its full potential of vibration control because of the fragility originating from excessive inter‐story drift of its secondary structures during earthquake. We propose an innovative subtype of mega‐substructure system to overcome this fragility and further improve its lateral aseismic performance. This subtype takes advantage of modular construction techniques. The secondary structures, which consist of suspended discrete modules, provide protection to nonstructural members against excessive inter‐story drift. Additionally, springs that provide inter‐story stiffness remain elastic. These effects extend the inter‐story drift limit of secondary structure and make sufficient relative motion possible. We carried out single‐objective and dual‐objective optimizations to derive optimum parameters and capture the potentials of representative models. Mean square responses under power spectral density functions of ground acceleration were set as optimization objectives. It is shown that the proposed systems further suppress the response of primary structure at the expense of additional response of secondary structure, which can be accommodated by the aforementioned protection effect. Mechanisms are revealed in the perspective of transfer function curves. Robustness and time history performances are also verified.

Huang, Baofeng; Lu, Wensheng; Chen, Shiming; Mosalam, Khalid M.

doi: 10.1002/tal.1388pmid: N/A

As a drift‐sensitive nonstructural component, the in‐plane deformation ability of the curtain wall (CW) in a tall building is critical to the seismic performance. The immediate earthquake excitation of the CW system is the floor response where the CW is located. To evaluate the drift demand of the outer‐skin CW system of the Shanghai Tower, floor responses of the reinforced stories of each vertical zone are analyzed. Drift demands, including the interzone drift ratio (IDR) and interzone drift response spectrum (IDRS), are obtained to define the engineering demand parameters related to the in‐plane relative displacement of the CW system. The results show that the 3‐dimensional ground motion (GM) excitations generate larger heightwise IDR distribution profiles and larger IDRSs than the 1‐dimensional GMs. The obtained IDR demands are shown to be 1/250, 1/150, and 1/100 for 3 key earthquake intensity levels. These values are different from those given by the current code provisions of China and other countries. The IDR distribution profiles of each vertical zone increase with height. The mean IDRSs of all 8 main vertical zones under selected GM excitations are determined as the representative drift spectra for each earthquake intensity level. Based on these mean spectra, simplified bilinear drift spectra are constructed for seismic design and analysis of the outer‐skin CW system of the Shanghai Tower.