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Expired Canadian patentCanada

Long span post-tensioned steel/concrete truss and method of making same

CA 2055377 C · Owner: Yee, Alfred A. · Inventors: Yee, Alfred A.

CIPO record

Overview

Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A long span truss of substantially conventional steel construction provided with concrete encasement of the top and bottom chords with the concrete encasement being reinforced and the concrete encasement on the bottom chord and optionally on the top cord including post-tensioned steel tendons. The invention further relates to a method of making the truss as described above in which the light structural steel truss is first erected and provided with temporary steel scaffolding and bracing to support formwork. Reinforcing steel and steel tendons are placed in the formwork and concrete is poured to encase the top and bottom chords of the truss. The steel tendons are post-tensioned to provide …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Filed November 13, 1991 and granted March 8, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 13, 2011.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 13, 2013.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 13, 1991
GrantedMarch 8, 1994
Term endedNovember 13, 2011
Patent numberCA 2055377 C
Classification (IPC)E04C3/02 +2 more

Timeline

Timeline From CIPO dates

1992199419961998200020022004200620082010Application filedNov 13, 1991Patent grantedMarch 8, 1994Term endedNov 13, 2011

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.