Tn 18A web-nov06. indd
Yüklə 324,88 Kb. Pdf görüntüsü
|
|
1
/
to
/
in. (3.2 to 6.4 mm) space should be left at each end of the lintel. These measures form a pocket that allows movement of the steel angle within the brickwork. Locating the expansion joint adjacent to the window will influence the dead weight of the masonry bearing on the lintel. Instead of the usual triangular loading, the full weight of the masonry above the angle should be assumed to bear on the lintel. See Technical Note 31B for more information about steel lintel design. If a vertical expansion joint cannot be built in this manner, do not place it alongside the opening.
junctions of walls with different environmental exposures or support conditions. Separate portions of brickwork exposed to different climatic conditions should be separated with expansion joints since each area will move differently. An exterior wall containing brickwork that extends through glazing into a building’s interior should have an expansion joint separating the exterior brickwork from the interior brickwork. You may need to use expansion joints to separate adjacent walls of different heights to avoid cracking caused by differential movement, particularly when the height difference is very large. Examples are shown in Figure 7
. Parapets. Parapets with masonry exposed on the back side are exposed on three sides to extremes of moisture and temperature and may experience substantially different movement from that of the wall below. Parapets also lack the dead load of masonry above to help resist movement. Therefore, extend all vertical expansion joints through parapets. Since parapets are subject to more movement than the wall below, they must be treated differently. When vertical expansion joints are spaced more than 15 ft (4.6 m) apart, the placement and design of expansion joints through parapets need to accommodate this additional movement. In this situation, make Yüklə 324,88 Kb. Dostları ilə paylaş:
|