# Effects of Corner Modification on the Wind-Induced Responses of High-Rise Buildings
## 1 Introduction  
With the burgeoning growth of the economy and construction industry, high-rise buildings are being widely built to meet the demand for social development [1]. Wind loads are one of the most critical parameters in the design stage to reduce the occupants' potential discomfort and the structure's cost. Due to the aerodynamic features, such as flow separation, wind effects on high-rise buildings are intrinsically sensitive to their external shapes [2]. Therefore, aerodynamic optimizations of building geometry have received significant attention in the design community. Typical approaches to aerodynamic optimization could be divided into two categories: minor modifications in the plan size, such as corner recessing, roundness, and chamfering, and the other is major modifications in the elevation size, such as tapering, setback, and twisting [3]. These approaches could reduce the cross-wind responses originating from the alternate vortex shedding from both sides of the building and intensified by the high-rise building's lower frequencies and damping levels. However, the major modifications have several inherent drawbacks, such as insufficient building area and excessively high construction costs [4, 5]. In contrast, minor modifications can maintain the original form to the utmost degree and coordinate with the surrounding space. The minor modifications in the cross-section can lead to significant changes in the airflow mechanism, resulting in the reduction in wind load acting on the buildings. The typical corner modifications mainly contain roundness, chamfering, and recession. At present, several studies have been conducted via various techniques, including thehigh-frequency force balance (HFFB), synchronized pressure integration (SPI), aeroelastic (AE) test, and computational fluid dynamics (CFD) to investigate the influence of section modifications on the wind-induced response of high-rise buildings. [PERSON] et al. [6] carried out force measurement tests on 15 building models in four terrain exposures by using the HFFB technique. They investigated the aerodynamic spectra and base force coefficients with different chamfering and recession rates. They confirmed that a modification ratio of around 10% would mitigate the amplitude of the aerodynamic spectrum in most frequency ranges. [PERSON] et al. [7] combined the aerodynamic optimization measures with the economic benefits of high-rise buildings via the HFFB technique. The aerodynamic spectrum and wind-induced response of structures with different chamfering and recession rates under the same total building volume and different heights are provided. They concluded that the recession measure has a better effect in reducing the along wind and cross-wind base overturning moment than the chamfer measure. [PERSON] et al. [8; 9] used the HFFB technique to investigate the base forces of high-rise buildings after corner recession, chamfering, and roundness. They examined the influence of the modification rate on the base aerodynamic forces and fitted the empirical formula of base force coefficient with the varied parameters. [PERSON] et al. [10] applied the corner modification method to the 509 m Taipei 101 building through the SPI test. They found that after the section with a double recession, the base overturning moments of the structure would be scaled down by 25%. [PERSON] et al. [11] conducted wind tunnel tests on super high-rise buildings with the taper along the height by the SPI method. They found that for the high-rise building with a taper ratio of 2.2%, the peak value of the base overturning moment after corner modification is 31% lower than that without chamfering. [PERSON] et al. [2] conducted SPI tests on four different section types of buildings, i.e., square, chamfering, recession, and roundness. They obtained the base moment coefficients, local wind coefficients, and aerodynamic spectra of the structures. They found that the recession and chamfering measures are more beneficial in alleviating the wind load on the buildings than the others.