Influence of architectural form on the wind-induced response of tall buildings

Moorjani, Rishabh Rajesh

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https://hdl.handle.net/2142/104927 Copy

Description

Title

Influence of architectural form on the wind-induced response of tall buildings

Author(s)

Moorjani, Rishabh Rajesh

Issue Date

2019-04-24

Director of Research (if dissertation) or Advisor (if thesis)

Lombardo, Franklin T.

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Wind tunnel testing
• Aerodynamic treatments
• High Frequency Force Balance
• Tall buildings
• Crosswind response
• Vortex shedding
• Vents
• Chamfers
• Fins

Abstract

Architectural form of a tall building can be the most influential factor in its performance under the action of wind. Traditionally, tall building projects include early stage architectural design that is often decoupled from engineering considerations. When wind tunnel testing of a set architectural form reveals any undesirable behavior, it must be mitigated through engineering modifications. These modifications typically include addition of structural material or supplementary damping devices. Modern-day awareness of the potential environmental impacts of construction has caused emphasis to be placed on economically and materially efficient building design, prompting designers to utilize preexisting material in innovative ways. Intelligent design of architectural forms enables the shape of a tall building to be a part of the solution to its crosswind excitation problem rather than worsen its effect. The phenomenon of vortex shedding is widely identified as the dominant cause of crosswind excitation in tall buildings. Reducing the coherence of vortex shedding along a building’s height, modifying separated shear layer structure, and stabilizing the near-wake region of a building have subsequently been identified as response mitigation techniques. Practically applicable aerodynamic treatments such as single- and double-vents, chamfering of corners, and addition of fins to a portion of the building were explored as a means to reduce crosswind excitation of a prismatic square building. In total, 43 architectural forms were tested at Skidmore, Owings & Merrill’s in-house boundary layer wind tunnel facility. The effect of freestream turbulence was also considered through the simulation of flows over both open and suburban terrain. An ‘influence zone’ was identified around 20-40% of the way down from the roof of prismatic square buildings. Optimal locations for single- and double-vents were determined within this influence zone. Double-vent treatments, at any two locations along a building’s height, were typically observed to be more effective than a single vent placed at either of those locations. Incremental chamfering and addition of different corner fins were applied to the top half of prismatic square buildings. Effectiveness of aerodynamic treatments in reducing the crosswind response of prismatic square buildings was evaluated and potential full-scale impact was assessed.

Graduation Semester

2019-05

Type of Resource

text

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http://hdl.handle.net/2142/104927

Copyright and License Information

Copyright 2019 Rishabh Moorjani

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