Repair and reconstruction of civil structures - Assessment and Refurbishment of Steel Structures - page 150

The case of the hall building of plan dimensions 19.85×67.5 m was more complicated.
The hall is covered by saddle roof structure. Lattice tie beams of triangular section with
subsidiary compression verticals rest on load-bearing external walls. The axial distances
in plan vary; places where there was the greatest corrosive damage (Figure 5.16), their
axial distance was 5.8 m. Longitudinal stiffening was incomplete. In the course of long-
term operation, substantial corrosive weakening of tie beams and trusses had occurred,
and thereby the integrity and functioning of the aluminium suspended ceiling and the
whole roof deck were impaired. The roof trusses at the drip were considerably damaged
by corrosion with losses reaching as much as 50 per cent.
In this hall, the following repairs were carried out:
• The tie beams were reinforced: (the upper and lower chords had their loading from
technical equipment removed, and new verticals were added
• A vertical stiffener was added between the tie beams.
Figure 5.16 Corrosion damage to
girders bedded in load-bearing
masonry