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This study examines how design features, such as building envelope openings and compartmentalization, affect the wind pressure in typical low-rise buildings with gable and hip roofs. Wind-induced internal and external pressures were investigated by using a full-scale wind testing facility generically known as Wall of Wind (WOW). The test-building m...
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... study case, a door measuring 0:96 3 0:46 m (3:15 3 1:50 ft) and a window measuring 0:53 3 0:43 m (1:76 3 1:43 ft) were used, which provided a porosity of 7.5 and 3.75% (area ratio of the opening to that of the wall where the opening was located), respectively. In addition, the door had three interchangeable openings, as illustrated in Fig. ...
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... internal wind pressures acting simultaneously in the same direction caused overloading of the envelopes, and hence, could have initiated failure under strong storms. For example, the external pressures that build up over the roof envelope coupled with the positive internal pressures that acted in the same direction generate a worst net pressure. Figs. 22(a and b) depict the results of the net internal pressure computation for each test case simulated with its respective AOA. Fig. 22(a) depicts the net suction internal pressure over the ceiling partition. It was observed that the peak suction pressure for Test Case 8 (window opening with all roof vents blocked) was critical at 0° ...
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... failure under strong storms. For example, the external pressures that build up over the roof envelope coupled with the positive internal pressures that acted in the same direction generate a worst net pressure. Figs. 22(a and b) depict the results of the net internal pressure computation for each test case simulated with its respective AOA. Fig. 22(a) depicts the net suction internal pressure over the ceiling partition. It was observed that the peak suction pressure for Test Case 8 (window opening with all roof vents blocked) was critical at 0° ...
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... geometric vari- ation. The net peak pressure that resulted from the net suction (ex- ternal) and positive (internal) attic pressure for the gable roof was 210% higher than the hip roof for the door-opened and hatch-opened cases. The gable roof's peak suction surged to 310% when the window-opened and hatch-opened cases were considered, as shown in Figs. 23(a and ...
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... Verma and Ahuja (2015b) have studied the effect of cylindrical roofs in single-span as well as double-span configurations. Tecle et al. (2015) have studied the opening and compartmentalization effects of internal pressure in low-rise buildings with gable and hip roofs. ...
The present study demonstrates the numerical investigation to find out the effects of roof shapes on the wind pressure distribution of multi-span low-rise buildings. Most of the wind load standards of various nations are provided with wind load information of isolated low-rise buildings which in turn practically came out to be inapplicable during the designing of low-rise buildings with multi-spans. Also, most of the wind load studies are carried out using boundary layer wind tunnel (BWLT) which is sometimes not available, time taking process, and is expensive. Therefore, in the present research, numerical simulation has been done for the model of a low-rise building. For investigation, the Ansys CFX platform has been used with the k-ε turbulence model for different angles of wind incidence at an interval of 15°. The wind pressure distribution has been investigated for the model low-rise building with a rectangular plan having six spans of different roof forms i.e., cylindrical roof, mono-slope roof, hip roof, and dome roof. The outcomes of the present numerical investigations are presented in the contour plots of wind pressure and coefficients of wind-induced pressure on the different roof forms of low-rise buildings. The outcomes of the study will be so much beneficial to structural design engineers while considering the wind loads calculations on the different roof forms for low-rise buildings.
... Holmes (1979), Stathopoulos and Luchian (1989) and Vickery and Bloxham (1992) focused on the fluctuating and/or mean internal pressures in buildings with a single dominant opening at the centre of the wall. Beste and Cermak (1997), Ginger et al. (1997), Kopp et al. (2008), Sharma (2008), Sharma and Richards (2003) and Tecle et al. (2015) considered multiple dominant opening locations (i.e., centrally located, at building edges, and a distance from the centre). Kopp et al. (2008) showed that the mean internal pressure coefficients are higher with openings near the corner of the wall than with centrally located openings. ...
... Several studies (Holmes, 1979;Saathoff and Liu, 1983;Liu and Rhee, 1986) focused on a case of a single dominant opening in the windward and leeward sides of the building, while others (Ginger et al., 1997;Kopp et al., 2008;Oh et al., 2007;Sharma and Richards, 2003;Tecle et al., 2015;Vickery and Bloxham, 1992) considered dominant openings and background leakage. ...
... ;Kopp et al. (2008);Sharma (2008);Tecle et al. (2015),Chowdhury et al. (2013) Feng et al. (2020) Number of openingsThe effect of having more number openings might not be the same as having a larger dominant opening area. Though increasing dominant opening sizes and the number of openings would increase internal pressures when located on windward sides of the envelope.Kopp et al. (2008) Geometry of opening The effect is insignificant.Humphreys et al., 2019b;Estephan et al., (2021) Volume of buildingThe larger the volume of the building, the lower the magnitude of internal pressures when opening sizes are constant. ...
Several post-hurricane studies have indicated the prevalence of roof damage in low-rise wood-frame buildings. One of the major reasons for this includes failure of roof-to-wall connections (RTWCs). This has led to a lot of research on RTWCs in a bid to understand the reasons for the failures, the capacities of the RTWCs and development of better RTWCs especially in hurricane prone regions. This study reviews the research works to date on factors affecting wind loads on RTWCs. It explores the experimental tests on RTWCs in roofing structures and component tests of single RTWCs. Numerical and analytical modeling of RTWCs as part of a roof system or as single connections are all reviewed. Finally, recommendations for future research works to bridge current knowledge gaps are made.
... Significant changes in wind pressures were observed. Tecle et al. [30] have studied the Opening and Compartmentalization Effects of Internal Pressure in Low-Rise Buildings with Gable and Hip Roofs. Gaur et al. [31] have worked on the interference effect on corner configured structures using CFD for different geometry and blockage configurations. ...
Through numerical simulations based on Computational Fluid Dynamics (CFD), this study examines the effect of wind load operating on a pitched roof and a circular arch roof of an identical plan area of a storage structure with one wall opening. Many numerical simulations have been performed by other researchers for other types of roofs to understand the behavior of wind flow associated with them. Also, the wind standards of multiple countries have provided the Coefficients of Pressures for standard building shapes. However, there is lack of similar work for structures having one wall opening. Ansys CFX fluid flow software has been used to carry out the simulations using a standard k-ε turbulence model. The simulations have been carried out for 7 wind incidence angles at an interval of 30ᵒ. Pressure, Force, Moment, Drag and Lift Coefficients generated on the roofs were compared. It was found that, although variation in these coefficients w.r.t the wind incidence angles are similar for both the roofs types, the sharp-edged rooftop of the pitched roof contributes to higher magnitudes of these coefficients as compared to the smooth arch roof. Mathematical modules between the face average of pressure coefficients and the wind incidence angles were established in a polynomial form which could be used to find the face average of pressure coefficients and corresponding pressures and forces for arbitrary wind incidence angles.
... Air leakage (i.e., infiltration or exfiltration) through openings or defects in the building envelope generates internal pressure. In addition, the background leakage inherent in nominally sealed buildings due to poor airtightness of walls, doors, windows, door-wall interfaces, window-wall interfaces, soffits, utility ducts, and vents also leads to internal pressure development (Tecle et al., 2015). During extreme wind events such as hurricanes, the wind inflow through openings and defects could contribute to the development of high internal pressures that, when combined with the external pressures, significantly increase the wind loads (Holmes and Cermak, 1980). ...
... Windward openings in a building are considered to be the critical design case, as they may lead to the development of high positive peak internal pressures (Holmes and Ginger, 2012). Various experimental and numerical studies have been conducted to investigate the effect of dominant openings on internal pressure (Aynsley et al., 1977;Ginger et al., 1997Ginger et al., , 2010Habte et al., 2017;Holmes, 1979;Humphreys et al., 2020;Kopp et al., 2008;Liu and Saathoff, 1982;Oh et al., 2007;Sharma & Richards, 2003Stathopoulos et al., 1979;Tecle et al., 2015;Woods and Blackmore, 1995;Wu et al., 1998). Research on the effects of building defects on the internal pressure was reported by previous studies (Harris, 1990;Ho et al., 2005;Holmes, 1979;Oh et al., 2007;Stathopoulos et al., 1979;Vickery, 1994), and a detailed summary of the experimental studies was provided by Oh et al. (2007) and Holmes and Ginger (2012). ...
Internal pressure is an important parameter in the estimation of wind effects on low-rise buildings. Cracks and defects located around building fenestrations, lead to air leakage that affects internal pressure. To assess this effect, an experimental study was conducted at the NSF NHERI Wall of Wind Experimental Facility at Florida International University on a full-scale building model. Defects of various sizes and shapes were modeled on one of the building walls. The effect of two simultaneous wall defects on the internal pressure was also investigated. In addition, an analytical procedure was used to predict the internal pressure caused by various wall leakage areas. Results of the analytical procedure were compared with those computed experimentally and reasonable agreement was observed for all leakage areas being considered. The experimental and analytical results showed that the internal pressure increases as the leakage area increases. The correlation between the external and internal pressures was evaluated for the walls and the roof, and the measured peak internal pressure coefficients were compared with those provided by ASCE 7–16 for enclosed and partially enclosed building configurations. It was shown that ASCE 7–16 peak internal pressure coefficients were underestimated for most of the leakage ratios being considered.
The full text can be accessed free of charge on ScienceDirect until Dec. 23rd, 2021 at https://authors.elsevier.com/a/1e0gC_3pvyZdR9.
... Large numbers of experimental tests and numerical models have been conducted to describe wind flow patterns and flow-structure interaction, in order to accurately predict internal and external pressures for coastal residential buildings (e.g., Richardson et al. 1990;Eaton and Mayne 1975;Richards et al. 2007;Liu et al. 2009;Wang et al. 2012;Tominaga et al. 2015;Tecle et al. 2015;Lambardo et al. 2018;Singh and Roy 2019;Ma et al. 2020). However, limited research has been reported related to the performance of low-rise elevated houses against wind loads. ...
Many elevated houses in coastal areas have suffered serious wind-induced damage during hurricanes; this indicates the need for better understanding of the performance of elevated homes subjected to higher wind forces or effects in open pile-supported areas. The actual direct and indirect wind-induced damage to elevated wooden residential houses in past hurricanes is briefly reviewed. Computational fluid dynamics (CFD) analysis was utilized to investigate the effect of wind angle and house elevation on the magnitude of mean negative or positive design pressures as an important variable affecting the vulnerability of the structural system. The numerical results were validated based on available experimental tests in terms of the mean pressure coefficient (C p) over the house surfaces. The CFD results show that elevating a house can result in increased wind speed and subsequent additional turbulence effects around the house, in particular at the exposed underside. The results indicate that elevating a house does not significantly affect the C p distribution on the roof surfaces, so that the roof uplift forces remain almost constant. However, elevating the house leads to increases in C p at various rates over the house surfaces, including exterior walls and along the underside. The rates of such increases depend on wind direction and house elevation. Regardless of wind direction, the overturning moment acting on an elevated 1:20 scale house increases about 50% and 95%, respectively, for 0.105 and 0.21 m elevations. Considering the scope and the limitation of the study presented in this paper, more studies are needed to better understand the effect of aerodynamic characteristics of elevated houses, particularly on peak positive or negative pressures over various building surfaces.
... A fullsized wind testing apparatus is generically called as Wall of Wind (WOW), as shown in fig. 2 and it has been utilized to evaluate wind-induced internal and external pressure coefficients on eaves of hip roof found considerably lower than gable roof. 99 A wall of wind always provides more realistic wind loading conditions as compared to other experimental methods. 61 In a wall of wind, the number of fans also vary and different types of roughness devices are used. ...
The statistics from previous cyclone reports and other relevant studies have shown a huge property loss and the loss of lives in both cyclone-prone areas and non-cyclonic areas. It is impossible to stop cyclones, but it is possible to minimize losses and to save lives from cyclone disasters. The wind load on a low-rise building is pertinent to a seemingly well-researched area. In the present study, the effects of roof shape, roof slope, aspect ratio, interference effect, etc., and the role of wind tunnels, wall of wind, CFD, and wind standards in wind force investigation have been discussed. Several research attempts have involved the effects of wind force on roofs of low-rise structures for so many past years. The theme remains a live region of inquiry, though there are so many motives for this investigation. In addition to the wide range of variables required, a reasonably large number of components disturb wind force on the roofs of low-rise structures. Furthermore, a huge number of structures indeed come under the "low-rise" investigation class forming new significant information pertinent to the protection of engineering structures, and even more relevant to loads of partially planned ones. Generally, wind codes are preferred for building design against wind loads in various countries, but in some studies, even the code values seem inaccurate.
... Many other studies were reported in the literature investigating wind loads on low-rise buildings adopting both experimental (Ginger and Holmes 2006, Corresponding author, Ph.D. E-mail: aelshae@uwo.ca Kopp et al. 2012, Tecle et al. 2015, Hajra et al. 2016) and numerical (Nozawa and Tamura 2002, Yang et al. 2008, Montazeri and Blocken 2013 methods. Furthermore, some studies introduced aerodynamic mitigation approaches as a way of reducing wind loads on low-rise buildings , Bitsuamlak et al. 2012, Aly and Bresowar 2016. ...
In coastal regions, it is common to witness significant damages on low-rise buildings caused by hurricanes and other extreme wind events. These damages start at high pressure zones or weak building components, and then cascade to other building parts. The state-of-the-art in experimental and numerical aerodynamic load evaluation is to assume buildings with intact envelopes where wind acts only on the external walls and correct for internal pressure through separate aerodynamic studies. This approach fails to explain the effect of openings on (i) the external pressure, (ii) internal partition walls; and (iii) the load sharing between internal and external walls. During extreme events, non-structural components (e.g., windows, doors or roof tiles) could fail allowing the wind flow to enter the building, which can subject the internal walls to lateral loads that potentially can exceed their load capacities. Internal walls are typically designed for lower capacities compared to external walls. In the present work, an anticipated damage development scenario is modelled for a four-story building with a stepped gable roof. LES is used to examine the change in the internal and external wind flows for different level of assumed damages (starting from an intact building up to a case with failure in most windows and doors are observed). This study demonstrates that damages in non-structural components can increase the wind risk on the structural elements due to changes in the loading patterns. It also highlights the load sharing mechanisms in low rise buildings.
... However, in spite of its specific features, very limited research work has been carried out in this specific area of wind load on pyramidal roof buildings (Roy et al. 2018b;Roy et al. 2018a). Maximum studies in this field are concerned with low-rise buildings with canopy roof (Roy 2010, a) gable roof, hip roof (Ahmad and Kumar 2001;Irtaza et al. 2015;Tecle et al. 2015;Habte et al. 2017), isolated pitched roof (Bourabaa et al. 2015), tall chimney (Verma et al. 2015;Khan and Roy 2017) and tall structures (Paul and Dalui 2008;Amin and Ahuja 2014;Kar and Dalui 2016;P. Martinez-Vazquez 2016;Sanyal and Kumar 2018), and aim to provide information about the consistency of performance and the upgrading of design economy (Isyumov 1999). ...
... A full-sized wind testing facility known as the Wall of Wind (WOW) was used to investigate wind generated internal and external pressures and pressure coefficients on the eaves of hip roofs which were found to be significantly lower than gable roofs (Tecle et al. 2015). The largest suction was found close to corner edges and near the ridgeline in the case of low-rise canopy roofs (Roy et al. 2010b(Roy et al. , 2007; similar results were noticed on roofs of other types of low-rise buildings. ...
Roof shape and slope are both important parameters for the safety of a structure, especially when facing wind loads. The present study demonstrates the pressure variations due to wind load on the pyramidal roof of a square plan low-rise building with 15% wall openings through CFD (Computational Fluid Dynamics) simulation. Many studies on roofed structures have been performed in the past; however, a detailed review of the literature indicates that the majority of these studies focused on flat, hip, gable and spherical roofs only. There is a lack of research that analyses these effects on pyramidal roof buildings. ANSYS (Analysis System) ICEM (Integrated Computer Engineering and Manufacturing)-CFD and ANSYS Fluent commercial packages have been used for modelling and simulation, respectively, and ANSYS CFD Post was used to obtain the results. A realizable k-ε turbulent model was used for the pressure distribution on the roof of the building model. In the present study, twenty-four models with different roof slopes (α), i.e. 0°, 10°, 20°, and 30°, with various wind incidence angles (ϴ), i.e. 0°, 15°, 30°, 45°, 60° and 75° were investigated. The influence of roof slope and wind incidence angle are analysed in this study. Results have been represented through pressure coefficient (Cp) contours on the roof surface and velocity streamlines of the flow field of the different cases. The optimization of the roof slope may be achieved by considering different wind incidence angles for buildings so that they may better withstand wind force in a specific area. When wind pressure coefficients from building models with openings were compared with pressure coefficients from building models without openings, it was found that the pressure coefficients for building models without openings are almost twice or three times that of the pressure coefficients for models with openings.
... A full-scale wind testing facility, generically known as Wall of Wind (WOW), has been used to investigate wind-induced internal and external pressures and pressure coefficients on the eaves of hip roofs and gable roofs. It was found that these coefficients were lower for the former i.e. hip roofs [23]. As the pressure or suction vary with the shape and size of structure and its roof, the highest suction was found near the corner edges and near ridgeline of roof in case of a canopy roof [24], and this type of roof was also found more vulnerable to windstorms as compare to other types of roofs [25]. ...
The present study demonstrates the pressure variation due to wind load on a two storey building with a square plan and a pyramidal roof through CFD simulation. Past cyclone reports and other related post-disaster studies have shown loss of lives and extensive property loss mostly in the cyclone-prone regions of India. Post-disaster studies reveal that a pyramidal roof has much better chances of survival in comparison with other roof shapes. ANSYS Fluent has been used for the simulation and ANSYS CFD-Post has been used for observing the wind pressure on building roofs. The simulations are performed using the realizable k-ε turbulent model by considering grid sensitive analysis and validation with previously published wind tunnel experimental measurements. The present study includes wind behavior around the building model with different roof slopes. Comparisons of pressure coefficients are shown for five wind incidence angles to study the effect of wind on the building. Results indicate that both maximum positive and maximum negative wind pressure coefficients increase with increasing roof slopes. The results of the study are helpful in understanding the damage caused on the roof surface during the extreme wind condition.
... (Uematsu and Isyumov 1999) also reported several wind tunnel and field pressure measurements for building roofs. On the same route, several researchers adopted both experimental ( (Kopp et al. 2012), (Tecle et al. 2015)) and numerical ( (Nozawa and Tamura 2002), (Montazeri and Blocken 2013)) techniques to investigating wind loads on low rise buildings. Aerodynamic mitigation approaches was also introduced by others as a way of reducing windinduced loads on building exterior including ( (Kopp et al. 2005), (Bitsuamlak et al. 2012)). ...
Low-rise buildings are vulnerable structures to wind damage during hurricanes, typhoons and extreme wind events. Various experimental and numerical studies were conducted on low-rise buildings to evaluate and control the wind-induced loads. These studies considered wind to be acting on the building external walls. This assumption can only be applicable for closed building envelops. However, during extreme events, buildings may lose some non-structural components (e.g. windows and doors), which will allow wind to enter the building envelop leading to alteration of flow field and redistribution of wind loads. Consequently, this transfer may subject the internal walls to additional lateral loads exceeding their typical load resistance capacities (i.e. internal walls are typically of lower capacities compared to external walls). Furthermore, Failure of windward façade may expose the structure to higher wind loads due to the increase in the total subjected area to wind. On the other hand, as the collapse of components progresses to leeward faces, the channeling flow through the building may distract the wake formation reducing loads on exterior walls. The current study examines a four-story gable roof house during a progressive collapse scenario. Computational Fluid Dynamic (CFD) simulations were used to study the progressive stages of building damage for wind azimuth (0 o). In addition to the undamaged stage, three damage stages were assumed. In the first two stages, building components in the windward direction were damaged allowing air to enter the internal spaces. While in the final stage, the damage reached the leeward components allowing the trapped air to channel through the building, which was found to decrease the overall load on the building.
