With a population of nearly 7 million, the people of Hong Kong occupy more than 39,000 buildings, of which more than 7,000 of them are skyscrapers – the highest number in the world. Of the top 100 residential high-rise structures in the world, 36 are located in Hong Kong. The natural sway of a building in the wind can potentially have an effect on the well-being and comfort of its occupants, especially at the upper levels of the building. Human perception levels, due to building motions in the low frequency range below 1 Hz, are dependent upon various physiological and psychological parameters. Human response to vibration and comfort is subjective and individualistic, leading to a wide range of occupant responses. As some occupants react by feeling unwell, suffering symptoms si...[ Read more ]

With a population of nearly 7 million, the people of Hong Kong occupy more than 39,000 buildings, of which more than 7,000 of them are skyscrapers – the highest number in the world. Of the top 100 residential high-rise structures in the world, 36 are located in Hong Kong. The natural sway of a building in the wind can potentially have an effect on the well-being and comfort of its occupants, especially at the upper levels of the building. Human perception levels, due to building motions in the low frequency range below 1 Hz, are dependent upon various physiological and psychological parameters. Human response to vibration and comfort is subjective and individualistic, leading to a wide range of occupant responses. As some occupants react by feeling unwell, suffering symptoms similar to that of seasickness, the equanimity of others may be adversely affected, with some possibly objecting to even small amounts of unexpected motion, and leaving them with a disconcerting feeling about the structural integrity of the building. During strong wind events, such as typhoons and monsoons, some occupants, especially those who are more sensitive to motion or those who are paying a premium to occupy the upper levels of buildings, may complain to the building management about the motion, and new homebuyers may even choose not to occupy the upper levels of tall buildings. In addition, employers in high-rise structures may notice a decrease in motivation, productivity, and cognitive ability from their employees, due to their staff becoming affected by the motion.

Additionally, it is human nature to interact with one another. Given these social interactions, it is inevitable that occupants (families and co-workers) will influence each other’s behaviour. Moreover, these influences vary according to society, across different regions around the world. As a building’s layout is designed specifically with a more social atmosphere, and with the sheer number of occupants in some buildings numbering in the thousands, it is this thesis author’s view that ignoring such social influences is unreasonable when it comes to perception of and human response to building sway. This is especially true when an occupants’ level of fear or anxiety is heightened, as occupants seek guidance about an ambiguous situation from other occupants. Exploratory analyses of possible factors, which may trigger a building occupants’ propensity to consider a complaint, were discussed. A building’s motion characteristics (frequency of oscillation, acceleration, and duration) or an individual occupant’s characteristics may define how an occupant responds to WIBM. Some “occupant characteristics” in the discussion included: psychology (e.g. personality), physiology (well-being effects), age, gender, motion sickness susceptibility, societal, and social grouping. These influential factors may include physiological and psychological effects to well-being and comfort, as well as societal influences, which may all play a role in defining acceptability. If so, then they should also be carefully considered in the design process. Occupant feedback can be a method of measuring and improving building designs, especially when the occupants do not expect the building to move. One method used to achieve the above-mentioned objective was the use of the wind-induced tall building motion simulator (WIBM) at the CLP Power Wind/Wave Tunnel Facility at The Hong Kong University of Science and Technology (HKUST). Volunteers for an extensive investigation were recruited to participate in a series of tests, using the motion simulator at HKUST to establish occupant comfort and effects to well-being, as well as whether a test subject may consider a complaint. Two motion simulator investigations (the “2007 Test” and “2008 Test”, respectively) and a General Population Survey were conducted whereby the above-mentioned factors were fully explored. Among some effects to well-being were examined in the 2007 Test and the General Population Survey were the self-assessed responses Nausea, Fatigue, Dizziness, Annoyance, Headache, Difficulty Concentrating, and Fear. Results from the 2007 Test indicated that as the Frequency increased, the percentage of test subjects who became Fatigued, Annoyed, developed a Headache and had Difficulty Concentrating, and Nauseous, also increased.

Based upon results from these three investigations, a “building’s motion characteristics” (the effects of Frequency, Acceleration, and Duration of motion) and “occupant characteristics” (Age, Gender, Motion Sickness Susceptibility, and Culture) were used to determine discomfort and the likelihood of whether an occupant would consider a complaint. Used in conjunction with wind tunnel testing to ascertain possible building accelerations, these quantitative models can then provide engineers and designers with a quick estimate of the likelihood of whether an occupant would consider a complaint during, while in the early design stages, thus incorporating an occupants direct feedback into their design plans. As outlined in this thesis, regression procedures were used to develop equations to ascertain discomfort and whether an occupant would consider a complaint. Both linear regression and logistic regression procedures (ordinal, multinomial, and binary) were conducted and subsequently analyzed to determine the best prediction model, with the highest classification percentages.

Additionally, when it comes time to purchase real estate property in the upper levels of tall buildings, some occupants may weigh their decision based upon theirs or their family members susceptibility to motion sickness. This decision to buy property has been shown to vary by culture, and thus acceptability of WIBM may not be universally applicable to all. Moreover, perhaps it may not be a matter of human perception threshold limits that determines acceptability. Occupants may find the motion within the limits of their own personal threshold but may still find the motion unacceptable. As the 2007 Test results has shown, of those test subjects who were aware that buildings moved in the wind, 1 in 5 still found the motion unacceptable. It is no longer just an issue of providing enough buildings to house the projected 9.2 billion world population by 2050 (UN 2010). The great challenge will be a matter of providing comfortable buildings beneficial to occupants.