Understanding accidental hybrid structure: an early concrete warehouse in the USA

Abstract

Building structures in discussion tend to be categorised using criteria similar to those used for new buildings: as a steel-frame building, as a masonry bearing wall and so on. Structural categories were different in the past because building technology was different, and the categories were generally broader and had more overlaps than those in use today, so by categorising, there may be miscategorising. For example, a building may have been intended by its designers to have a skeleton frame carrying non-structural curtain walls, but the walls were constructed as 406 or 508 mm of solid brick without expansion joints. In such a case, the walls will function as bearing walls whether intended to be so or not. In broad terms, that is a description of this case study, except that the building in question, building G at Bush Terminal, USA, has a frame that blurs the boundary between skeletons and bearing walls. While it appears that the designers of the building thought of it as having a concrete frame, modern analysis shows it to be a hybrid of a frame and a bearing wall.