investigation of irregular-shaped buildings and their
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6th American Association for Wind Engineering Workshop (online) Clemson University, Clemson, SC, USA
May 12-14, 2021
* Manuel Matus
Investigation of irregular-shaped buildings and their pressure distribution
Manuel Matus a*, Ioannis Zisis b
a Florida International University, Miami, Florida, USA, mmatu016@fiu.edu b Florida International University, Miami, Florida, USA, izisis@fiu.edu
ABSTRACT:
Wind related damages on low-rise residential buildings have caused billions of dollars in losses. Building code
provisions, that have been developed to mitigate such impact, were predominately based on testing models of regular
plans. This study aims at evaluating the wind-induced loads on buildings with non-rectangular shapes. Six models
with irregular shaped plans were tested at the Wall of Wind Experimental Facility at Florida International University.
Preliminary results showed that separation zones are more complex than those observed in a regular shaped building
and result in higher local and overall peak pressures. Preliminary area averaging curves have shown that current wind
standards might underestimate the actual pressures building undergo. Additional testing is ongoing to better
understand the effect of building shape in the local and overall pressure distribution.
Keywords: wind load, low-rise building, irregular-shaped
1. INTRODUCTION
Extreme wind events have caused billions of dollars in losses in the low-rise residential building
sector and are expected to increase to 39 billion dollars by 2075 (USDOC 2010, CBO 2019).
Current wind standards provide guidance for the safe design of residential structures to reduce
potential damages due to wind induced loads (ASCE 7-16). These wind load provisions have been
developed based on results obtained from wind tunnel testing on regular shaped structures in the
late 1970’s (Akins et al., 1977, Davenport et al., 1977 and Stathopoulos 1979) and have been
enhanced and improved over the next few decades through several wind tunnel studies. With
advancements on technology and construction techniques, the shapes of structures have become
considerably more complicated than just rectangular and squared shapes. As a result, several wind-
tunnel and numerical investigations have been carried out to better understand the effects of
extreme wind events on such structures; however, most have focused on mid- to high-rise
structures (Shuai et al., 2019; Stathopoulos et al., 1993; Mashalkar et al., 2015; Gomez et al., 2005;
Young et al., 2016; Souvik et al., 2014; Yi et al., 2016, 2017, 2020; Don-Xue et al., 2017).
Although current building codes provides guidance on how to account for building plan
irregularities, there are no guidelines on how to account for the aerodynamic effects caused by
complex shapes. Some investigations have concluded that there has been a lack of attention on the
investigation on low-rise residential buildings and that the current building code wind provisions
underestimates the actual wind loads on such structures (Stathopoulos 1984 and Jin et al., 2020).
2. METHODOLOGY AND TEST PLAN
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6th American Association for Wind Engineering Workshop (online) Clemson University, Clemson, SC, USA
May 12-14, 2021
To obtain the most common irregular shapes of low-rise residential structures, several satellite
images of South Florida residential areas were obtained and visually analysed. From these images,
T, L and C were observed to be the most common shapes. Having identified the shapes, dimensions
were obtained and a total of seven models were designed and constructed (two T-, L- and C- and
one Rectangular-shaped model) out of 3/8” plexiglass, at a 1:50 scale and instrumented with
approximately 350 pressure taps each. The models were tested at the Wall of Wind (WOW)
Experimental Facility at Florida International University in Miami, Florida, with an open terrain
exposure. The tests were carried out at 30 mph with a 15degree wind direction step.
3. RESULTS
From the experimental data obtained, pressure coefficients (𝐶𝑝,𝑚𝑒𝑎𝑛 𝑎𝑛𝑑 𝐶𝑝,3𝑠) were acquired and
some of the contour plots are presented here. The rectangular model served as the base model and
was compared against NIST and TPU results with satisfactory agreement (Ho et al., 2005, Tamura
2012). Representative cases of the 𝐶𝑝,𝑚𝑒𝑎𝑛 for a T- and an L-shaped models at 0 degrees is
presented in Figure 1 and Figure 2. The pressure distributions reveal that these structures develop
more separation zones than a regular shaped structure due to the increased number of sharp
edges/corners, thus experiencing more local and overall peaks. Area averaging calculations, for
roof and walls, were also generated with peak pressure coefficients for all examined wind
directions. These graphs provide information to estimate the critical pressures that components
and cladding (C&C) elements can experience based on their different surface areas. They also
provide the means to compare results to current building code wind load provisions envelope
curves. This preliminary exercise showed that current recommendations may underestimate the
wind-induced pressures on more complex building shapes.
Figure 1. Mean Cps model T1
Figure 2. Mean Cps model L1
4. CONCLUSIONS
Low-rise residential structures are highly susceptible to wind-induced damage. Substantial
economical loses indicate the urgent need to enhance the survivability and resilience of residential
construction. Wind load provisions were developed based on regular-shaped isolated-models
tested in wind tunnel over the past 40 years. Today’s built environment has evolved in structures
having complex shapes making the design process of such structures somewhat intuitive. The work
presented in this paper provides preliminary findings obtained from testing seven irregular shaped
models at the WOW Experimental Facility. Results show that buildings having irregular plans
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6th American Association for Wind Engineering Workshop (online) Clemson University, Clemson, SC, USA
May 12-14, 2021
have more edges where flow separation occurs, areas which are known to develop high suction
zones thus resulting in high local and overall peak pressure coefficients. Area averaging curves
developed from the tested cases, show that ASCE 7-16 might underestimate the loads that
buildings with irregular shapes undergo. A comprehensive investigation is needed to fully
understand the effect of irregular plans in the local and overall pressure distribution as well as the
aerodynamics of such structures to mitigate wind induced damages.
5. REFERENCES C. B. O. Congress of the United States, "Potential Increase in Hurricane Damage in the United States: Implications
for the Federal Budget," June 2016.
Dong-Xue Zhao, Bao-Jie He. 2017. Effects of architectural shapes on surface wind pressure distribution: Case studies
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irregular-plan shapes. Journal of Wind Engineering and Industrial Aerodynamics.
Ho, T. C. E., D. Surry, D. Morrish, and G. A. Kopp. 2005. The UWO contribution to the NIST aerodynamic
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6th American Association for Wind Engineering Workshop (online) Clemson University, Clemson, SC, USA
May 12-14, 2021
Young Tae Lee, Soo Li Boo, Hee Chang Lim, kunio Misutani. 2016. Pressure distribution on rectangular buildings
with changes in aspect ratio and wind direction. Wind and Structures. Vol. 23, No. 5 (2016) 465-483.
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