Friday, December 11, 2015

Vierendeels Configurations

Vierendeels may have various configurations, including one-way and two-way spans. One-way girders may be simply supported or continuous over more than two supports. They may be planar or prismatic with triangular or square profile for improved lateral load resistance.  Some highway pedestrian bridges are of the latter type.  A triangular cross-section has added stability, inherent in triangular geometry.  It could be integrated with bands of skylights on top of girders.

When supports are provided on all sides, Vierendeel frames of two-way or three-way spans are possible options.  They require less depth, can carry more load, have less deflection, and resist lateral load as well as gravity load.  The two-way option is well suited for orthogonal plans; the three-way option adapts better to plans based on triangles, hexagons, or free-form variations thereof.

Moment resistant space frames for multi-story or high-rise buildings may be considered a special case of the Vierendeel concept.

1  One-way planar Vierendeel girder
2  One-way prismatic Vierendeel girder of triangular cross-section
3  One-way prismatic Vierendeel girder of square cross-section
4  Two-way Vierendeel space frame
5  Three-way Vierendeel space frame
6  Multi-story Vierendeel space frame

Vierendeels Configurations