Repair and reconstruction of civil structures - Assessment and Refurbishment of Steel Structures - page 139

Chapter 5
Repair and reconstruction of civil
structures
5.1 Hall structures
5.1.1 Reconstruction of the roof structure of a stadium
During extensive modernization of the Winter Stadium in Bratislava, its steel roof
structure was reconstructed. The original reinforced concrete skeleton with plan
dimensions of 70.0×100.0 m was built over the period 1943-52. The raised seating
around the ice rink was covered by a reinforced concrete decking with an 8.0 m overhang
supported by a continuous girder in turn. This was supported by round reinforced
concrete columns located 10 m apart. The load-bearing system for the raised seating was
a transverse frame (Figure 5.1).
In 1957 the stadium ice rink was roofed [51] according to the proposal by Professor A.
Tesar et al. which used a system of flat two-hinged steel-frame cross bonds of 52.8 m
span (Figure 5.1). The horizontal forces on the two-hinged frames were absorbed by a
closed horizontal lattice stiffener (Figure 5.2) suspended from an inclined draw bar on the
frames. The columns under the new cross bonds were reinforced by 420/12 steel pipes.
The space between the original reinforced 350 mm concrete column and the steel
jacket was injected with cement mortar. Longitudinal strength was secured by stabilizing
frames. The axial distance between the roof trusses was 5.0 m. The load-bearing
underlayer of the roofing material, timber form work, was bedded on trusses at an axial
distance of 1.67 m. The roofing itself was made from double hardboard protected by
ruberoid coating.
Before the planned reconstruction of the structure in 1987, specialists prepared an
expert assessment of the steel and reinforced concrete load-bearing structure [52], the
roof deck and the foundation structures. They found that:
• The structure of the roof deck and lighting in the plane of the inclined draw bars did not
meet the spatial requirements for its micro-climate and that heat insulation should be
provided to improve the energy economics of the building
• The original cross bonds—flat two-hinged steel frames with 52.28 m span—would not
meet the requirements of the new loadings from the heat-insulated roof and
maintenance footbridges