Improvements in or relating to a crack-controlling joint strip

摘要

769,592. Expansion joint strip. WILLIAMS, C. I. Nov. 4, 1954, No. 31964/54. Class 20(4) A yieldable expansion joint strip 5 for use in a monolithic concrete structure such as a wall, pavement or foundation, comprises a trapezoidal strip 10 having integral side stiffening arms 15, the wider inner end of the strip being provided with a nailing groove 13 to facilitate the alignment of a series of casing nails 14 which are driven through the strip to attach it, before the pouring of concrete, to temporary shuttering 7 with the opposite and narrower concave face 11 of the strip against the shuttering. After the concrete has set, and the shuttering has been removed, any nails 14 left in the strip can be withdrawn, by pulling their pointed ends, which now project from the strip. Expansion and contraction of the concrete results in a cracked portion at the predetermined weakened location 26 to relieve the stress in the wall, the crack 26 being sealed from outside by the strip 5. Reinforcing bars, such as 24, should be cut, or stopped, at an expansion joint, however, bars provided as beam reinforcements, not shown, should be continuous through the joints. In a modification, Fig. 3, the side arms 15 have been omitted, a reinforcing thin metal strip 18 being attached to the under edge of the strip 10 after it has been nailed to the shuttering to maintain it in alignment during the concrete pouring process.