The Structural Design of Tall and Special Buildings

Zhou, Lei; Tse, Kam Tim; Hu, Gang; Guo, Zijian

doi: 10.1002/tal.2050pmid: N/A

This study investigates the aerodynamic performance of three square‐section buildings with different aspect ratio (AR = 1:1, 1:4, and 1:6) exposed to twisted wind profile (TWP) by pressure measurement test. The effect of AR on the correlation of wind loads specifically for TWP is systematically revealed from both time–frequency domain and local–global perspective. Results show that compared with its counterparts in conventional wind profile (CWP), the effect of AR on aerodynamic load under TWP becomes significantly different and more prominent, which can be categorized into two types of patterns. For pattern low‐rise building, TWP is more resembling the condition of CWP with certain attack angle. For pattern high‐rise building, TWP results in stronger momentum exchange along building height but suppresses fluctuating feature associated with Karman vortex. As a result, under TWP, mean base moments of all buildings are enhanced except for longitudinal component of case AR = 1:4 and 1:6; while the fluctuating base moment for three AR cases is all reduced, which indicates that dynamic pattern of wake flow is suppressed. Moreover, the discrepancy of local wind load between case CWP and TWP concentrates on the lower‐middle location for high‐rise building but distributed evenly along all low‐rise building height. Additionally, it is found that the effect of AR on aerodynamic correlation exhibits different mechanisms and patterns when building is under the impact of CWP or TWP.

Doroudi, Rouzbeh; Hosseini Lavassani, Seyed Hossein; Shahrouzi, Mohsen

doi: 10.1002/tal.2049pmid: N/A

Recovering missing data of defective sensors is an important challenge for reliability of structural health monitoring systems and misjudgment of structural conditions. The present study concerns predicting corrupted data of lost sensors by support vector regression (SVR). The method is tuned via optimizing their parameters by observer–teacher–learner‐based optimization as a powerful meta‐heuristic algorithm. Their performances are compared in predicting the acceleration responses of two real‐world super‐tall buildings: Milad Tower, located in Tehran, and Canton Tower in Guangzhou. Also the minimum required of sensors to predict the acceleration responses are investigated. The results are evaluated by five statistical indices exhibiting that the optimized SVR has sufficient capacity to predict acceleration responses of both towers with limited number of sensors. The proposed method is of practical interest as it does not require finite element modeling of the structure to derive its dynamic responses.

Xu, Fan; Ji, Baifeng; Xiong, Qian; Liu, Guangyi; Qiu, Penghui; Xing, Panpan; Liu, Hui; Xu, Shuaijun

doi: 10.1002/tal.2046pmid: N/A

Inner Mongolia is a high‐frequency thunderstorm region in China, and the downburst caused by the thunderstorm weather is a severe threat to buildings. In order to study the influence of downburst on the wind pressure characteristics of the yurt building, the wind field model of the yurt building under downburst is established based on the computational fluid dynamics method, and the effect of the wall treatment method and turbulence model on the numerical simulation of wind pressure of the yurt building under downburst is analyzed. The results demonstrate that the maximum positive pressure at the windward side of the yurt building occurs at 3/4 of the yurt building height under downburst, and the maximum negative pressure at the roof of the yurt building appears at the center of the roof. Compared with the experimental results, the Shear Stress Transport (SST) k‐ω model is suitable for simulating both sides of the yurt building, while the Reynolds Stress equation Model (RSM) is suitable for simulating the windward side, roof, and leeward of the yurt building. The enhanced wall treatment is appropriate for simulating the remaining sides of the yurt building while the standard wall function is appropriate for simulating both sides of the building.

Wu, Jianbin; Liu, Ruyue; Yan, Guiyun; Lai, Qiulan

doi: 10.1002/tal.2053pmid: N/A

Bolted connections are preferred in prefabricated steel structures with the advantages of quality control and convenient construction. An innovative type of earthquake‐resilient joint with slotted bolted connection (ERJ‐SBC) is proposed to achieve damage control and improve the ductile behavior of steel structures. The bending moment is assumed to be mainly transferred by the flange segments of SBC while the shear force is carried by the web segments. The energy dissipation capacity of ERJ‐SBC is provided by the initial frictional sliding and inelastic axial deformation of SBC under larger displacement. Design theory is proposed to ensure that inelastic deformation is concentrated in SBC while other structural members remain elastic. The influences of the length of slotted holes, bolt pretension, friction coefficient, and the thickness and width of the sliding plate are investigated through the numerical analysis of 44 FE examples. The calculation of the critical length of slotted holes for the ductile rotation behavior of ERJ‐SBC is derived and verified. Results demonstrate that the mechanism of bolted connection shifts from friction resistance to bearing resistance when bolts collide with slotted holes, and the friction slippage behavior with slotted holes benefits the hysteresis behavior, deformation capacity, and rotation behavior. The proposed calculation methods for the mechanical behavior of ERJ‐SBC could achieve good accuracy with simulation results. A reasonably well‐designed ERJ‐SBC could have good bearing capacity and rotation behavior, and it could also achieve damage control.

Van, Chung Nguyen; Ghamari, Ali

doi: 10.1002/tal.2042pmid: N/A

The concentrically braced frame (CBF) suffered from low dissipating energy capacity although it pertains to a high lateral elastic stiffness and ultimate strength. To overcome the shortcoming, in this paper, an innovative damper made of two butterfly‐shaped plates installed at the end of the diagonal member of the CBF was considered experimentally and numerically. Also, the required equations were presented to design the system. In an experimental study, the damper showed stable hysteresis loops without any degradation in stiffness and strength up to a rotation of 12% (0.12 rad). This rotation capacity is 50% greater than the AISC limitation. Also, the numerical study indicated that by increasing the angle of main plates, the structural parameters are improved as ultimate strength (Fu), 47% to 90%; stiffness (K), 64% to 97%; energy absorption (E), 23% to 11%; and overstrength (Ω), 59% to 96%. By reduction of the damper's height, the parameters Fu, K, E, and Ω are increased by 47% to 76%, 23% to 64%, 49% to 93%, and 23% to 27%, respectively. Moreover, although the geometry of the damper affected the elastic stiffness, the stiffness in the nonlinear zone was independent of the geometry of the damper. Correspondingly, the slenderness limitations were suggested as 15 for height to thickness ratio and 22 for wide to thickness ratio.

doi: 10.1002/tal.1964pmid: N/A

No abstract is available for this article.