The collapse of the space frame building
Bashu Jiangyou Power Plant steel structure warehouse №33 and №34 (2×300MW) steam turbine roof grid span is 27m, and there are two 75/20t light duty cranes. The cross-section of the grid is double-slope type, and the grid unit adopts the square pyramid. The grid supports are placed on the reinforced concrete joists and column corbels.
During the 5.12 Wenchuan earthquake, the space frame structure of the steam turbine house of №33 engine collapsed as a whole, except for part of it that fell on the 0m ground of the maintenance span and on the crane, the rest fell on the platform of the running floor and the main engine such as the steam turbine was covered by the falling objects. The dropped grid has completely disintegrated. The roof grid of №34 unit has not collapsed. After inspection, it was found that some rods had bending deformation visible to the naked eye.
The transition plate under the bottom plate of the space frame support and the welded seam of the embedded parts are intact. The damage of the space frame at the support is mainly because the connecting bolts between the bottom plate and the transition plate are pulled out of the grid. Other parts of the grid are also at the bolt ball joints. Bolts were cut. The concrete components supporting the space frame (columns A and B, corbels, joists, etc.) and the embedded parts connected to the grid at the fixed end of the gable are also intact without any shedding. See Figure 1 to Figure 2 for the damage to the grid frame of the turbine house of Unit 33.
The main reason for the collapse of the space frame roof of the steam turbine room of Unit 33 designed in 2003 was the action of huge earthquake forces that exceeded expectations. The grid roof of №33 steam engine room designed according to the seismic fortification intensity of 7 degrees was subjected to the earthquake action of nearly 10 degrees in the Wenchuan earthquake. The vertical seismic action may cause the internal force of the grid members to change the overall torsional effect of the main powerhouse structure It may make the corner supports of the grid structure fail first and cause the overall collapse of the grid structure. In addition, after the earthquake, it was found that although the grid roof of the steam engine room of Unit 34 did not collapse, some members of the grid had buckling phenomenon. The grid nodes and supports could not be tested, detected and identified. 2×300MW) grid roof is also dismantled as a whole and replaced with ordinary steel roof truss roof. The problem worth considering is that the ordinary steel truss roofs of №31 and №32 engine rooms (2×300MW) designed according to the seismic fortification intensity of 6 degrees in 1985 were not damaged or collapsed in a major earthquake. These situations indicate that there are some congenital defects and problems in the design, manufacture, construction and installation of the warehouse steel structure steam turbine house using the grid structure. There are still many problems that need to be analyzed and studied when the space frame structure is applied to the roof structure of the steam turbine.
So for space frame construction, to find a professional space frame manufacturer is how important
