The Structural Design of Tall and Special Buildings

doi: 10.1002/tal.1131pmid: N/A

No abstract is available for this article.

Young, Kelly; Adeli, Hojjat

doi: 10.1002/tal.1136pmid: N/A

This paper presents the results of investigation on the fundamental periods of concentrically braced frame (CBF) structures with varying geometric irregularities. A total of 12 CBFs are designed and analyzed. On the basis of the results obtained from vibration theory, equations for the approximate fundamental periods are put forth for CBFs, which take into account vertical and horizontal irregularities. Through statistical comparison, it was found that a three‐variable power model that is able to account for irregularities resulted in a better fit to the Rayleigh data than equations that were dependent on height only. The proposed equations were validated through a comparison of available measured period data for CBFs. These proposed equations will allow design engineers to quickly and to accurately estimate the fundamental period of CBF structures by taking into account irregularities. Copyright © 2013 John Wiley & Sons, Ltd.

Gu, M.; Cao, H. L.; Quan, Y.

doi: 10.1002/tal.1137pmid: N/A

Across‐wind aerodynamic damping ratios are determined from the wind‐induced acceleration responses of 10 aeroelastic models of square super high‐rise buildings in an urban flow condition (exposure category C in the Chinese code) using the random decrement technique. Moreover, the influences of amplitude‐dependent structural damping ratio on the estimation of aerodynamic damping ratio are discussed. The validity of estimated damping is examined through a comparison with previous research achievements. On the basis of the estimated results, the characteristics of the across‐wind aerodynamic damping ratios of modified square high‐rise buildings are studied. The effects of aerodynamically modified cross‐sections, such as chamfered, slotted and tapered cross‐section, on the across‐wind aerodynamic damping ratio are investigated. The results indicate that modifications of cross‐sections are not always effective in suppressing the aeroelastic effects of super high‐rise buildings. Low corner‐cut ratios (chamfer ratios from 5% to 20% and slot ratios from 5% to 10%) and low taper ratio (1%) significantly decrease the magnitudes of absolute aerodynamic damping ratios. However, large modifications of cross‐sections (slot ratio of 20% and taper ratios from 3% to 5%) increase wind‐induced responses by changing the aerodynamic damping ratios. According to the database, empirical aerodynamic damping function parameters are fitted for high‐rise buildings with aerodynamically modified square cross‐sections. Copyright © 2013 John Wiley & Sons, Ltd.

Yahyai, Mahmood; Amiri, Mohammad Mahdi

doi: 10.1002/tal.1138pmid: N/A

It is necessary to have reliable field measurement records for estimation of dynamic characteristics. Increasing duration of the record is one of the common methods for reduction of such errors in the results. Dynamic characteristics of telecommunication towers in higher modes are important for designers, but these parameters could be obtained from ambient vibration monitoring during typhoons in which duration of vibration is not long enough for reducing measurement errors.

Hart, Gary C.; Jain, Anurag

doi: 10.1002/tal.1139pmid: N/A

This paper presents a methodology in wind design including in a scientific way the benefits of using dampers and of performing a nonlinear dynamic analysis of tall concrete buildings that are being evaluated and strengthened. It is developed for tall buildings in the Los Angeles region but is without geographic bounds. The uses of equations of structural reliability form this scientific basis. Copyright © 2013 John Wiley & Sons, Ltd.