Extreme Wind Pressures and Non-Gaussian Characteristics for Super-Large Hyperbolic Cooling Towers Considering Aeroelastic Effect

The disposal of discarded tires is a problem of significant proportion. In the present experimental study, rubber produced from the granulation of discarded tires was used as an additive to replace certain portions of mineral aggregates in concrete. This rubberized concrete was used in making thin panels. A layer of polymer grid was used to reinforce the rubberized concrete panels. These panels were developed to study their performance in applications where the concrete could be subjected to flexure. Buildings constructed in areas with extreme wind pressures resulting from hurricanes or tornadoes are examples of structures that require concrete that can handle considerable deformation without failing catastrophically. Three different panel thicknesses, three different water-cement ratios, and three different rubber contents were the parameters evaluated in this study. All panels were loaded in bending with two equal loads applied at two equal distances from the supports. Test results showed that the flexural resistance of the panel increases with an increase in the thickness of the section, and with a reduction in the water-cement ratio of the concrete. The panels behaved in a ductile manner and there were no signs of brittle failure. Considerable deformation was measured during load application where loaded panels fractured but remained intact relying on the elongating polymer reinforcement. In addition to the lightweight properties, it was concluded that rubber concrete and polymer grid could be used as effective tools to impart ductility to the concrete and to control the mode and nature of the brittle failure of conventional concrete.

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Wind-induced internal pressures on large cooling towers

Advances in Structural Engineering ◽

10.1177/1369433219861727 ◽

2019 ◽

Vol 22 (15) ◽

pp. 3249-3261

Author(s):

XX Cheng ◽

G Wu ◽

L Zhao ◽

PF Li ◽

YJ Ge

Keyword(s):

Internal Pressure ◽

Cooling Tower ◽

Dominant Factor ◽

Cooling Towers ◽

Theoretical Formulation ◽

Internal Surfaces ◽

External Pressures ◽

Strong Winds ◽

Wind Pressures ◽

Internal Pressures

Effects of wind-induced internal pressures on the cooling tower’s structural performances are as significant as those of wind-induced external pressures. However, comparing to wind-induced external pressures, limited research focuses on wind pressures on the internal surfaces of large cooling towers. To fill up the scientific void, numerical analyses, physical model tests, and analytical studies are undertaken in this article. It is demonstrated that the draught ventilation ratio (i.e. the total area of the openings on the stuffing layer divided by the area of the stuffing layer) is the dominant factor for wind-induced internal pressures on large cooling towers, and 15% draught ventilation ratio can be regarded as the most unfavorable case. Besides, it is revealed that the theoretical formulation of the internal pressure on a single-cell building with a dominant opening and background porosity proposed by some other researchers can be applied to the case of a cooling tower subjected to strong winds. Using the validated theoretical formulation, the geometry of a large cooling tower is optimized with regard to the most favorable wind-induced internal pressure. The findings of this article are helpful for improving the current Chinese Code that governs the design of cooling towers.

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Influence of Non-Gaussian Local Wind Pressures on Fatigue Damage of a Cladding Fastener on a Side Face of a Tall Building

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.353-358.2660 ◽

2007 ◽

Vol 353-358 ◽

pp. 2660-2663

Author(s):

Nag Ho Ko ◽

Young Moon Kim ◽

Ki Pyo You ◽

Dong Pyo Hong

Keyword(s):

Fatigue Damage ◽

Separated Flow ◽

Tall Building ◽

Building Structures ◽

Local Wind ◽

The Central Limit Theorem ◽

Rainflow Cycle Counting ◽

Side Face ◽

Wind Pressures ◽

Non Gaussian

The action of wind pressures is a major consideration in the design of cladding and its connections to building structures. Non-Gaussian environmental loads often may appropriately be reduced to Gaussian loads through the central limit theorem, e.g., integral loads on a building under wind loads. However, for the design load of cladding and its connections to building structures the Gaussian assumption is not valid and loads remain non-Gaussian, especially in separated flow regions. When the loads differ significantly from Gaussian distribution, they may lead to increase expected damage. In this study, the wind-induced high-cycle fatigue damage of a cladding fastener subjected to non-Gaussian local wind pressures and corresponding simulated Gaussian local wind pressures is estimated by using the rainflow cycle counting method and Miner’s rule. The fatigue damage is compared with each other in order to investigate the influence of non-Gaussian local wind pressures on the fatigue damage of a cladding fastener on the side face of a tall building.

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