ASCE MOP 126

Abstract

<strong>INTRODUCTION</strong> <br>The architectural appeal of glass comes from its most obvious properties&#8212; light refl ectance and transmittance. In daylight, glass refl ects its surroundings. On a high-rise tower blue sky is seen refl ected on a clear sunny day, clouds on an overcast day, and lit offi ces at night. Glass gets your attention. The dynamic, always-changing appearance of a glass-clad tower is not possible with any other building material. Light transmission allows natural indoor lighting and a view from inside the building, providing a closer connection to the natural outdoor environment. Refl ectance and transmittance&#8212;properties unique to glass&#8212;have increased its popularity and use in multistory construction. <br>The wall of glass seen in high-rise construction is a sophisticated manufactured product called curtain wall. Separating and moderating the interior building environment is its primary function. As an environmental separator it must keep out air and water; reduce heat loss in cold weather and reduce solar heat gain in warm weather; safely support wind loads, which become signifi cant on high-rise buildings; accommodate thermal movement due to temperature fl uctuations throughout the day and changing seasons; and accommodate building interstory movements caused by wind, live, and seismic loads. In certain geographical locations, extreme events require special design consideration for impact forces from fl ying debris in hurricane winds or large interstory movements caused by seismic events. Other special design considerations include reducing fi re spread from fl oor to fl oor or across a fl oor at the structural slab edge and preventing injury to occupants from a blast event.