1. The arrangement of braced frames in both directions should be basically symmetrical, and the ratio of length to width of floor between braced frames should not be greater than 3.
2. 3, 4 grades of steel structures with height not more than 50 m should be supported by central braces, eccentric braces, buckling restraint braces and other energy dissipation braces.
3. The central braced frame should be supported by cross bracing, herringbone bracing or single inclined bar bracing, not K-shaped bracing; the braced axis should intersect at the intersection point of the beam-column component axis, and the eccentricity should not exceed the width of the braced member when deviating from the intersection point, and the additional bending moment should be taken into account. When the central support adopts a single inclined bar system which can only be tensioned, two groups of inclined bars with different inclined directions should be set simultaneously, and the difference of the cross-section area of the single inclined bar with different directions in each group should not be greater than 10% in the horizontal direction.
4. Each support of eccentrically braced frame should have at least one end connected with frame beam, and form energy dissipation beam segment between support and beam intersection point and column or between another support and beam intersection point in the same span.
5. When using buckling restraint bracing, it is advisable to use herringbone bracing, paired single-inclined bar bracing and other forms, not K-shaped or X-shaped bracing, and the angle between bracing and column should be between 35 and 55. When buckling restrained braces are subjected to compression, their design parameters, performance tests and calculation methods as two kinds of energy dissipation components can be designed according to relevant requirements.
What is the selection of damping ratio for seismic calculation of steel structures?
1. In the calculation of frequent earthquakes, 0.04 is preferred when the height is not more than 50 m; 0.03 is preferred when the height is greater than 50 m and less than 200 m; 0.02 is preferred when the height is not less than 200 m.
2. When the seismic overturning moment of the eccentrically braced frame is greater than 50% of the total seismic overturning moment of the structure, the damping ratio of the eccentrically braced frame is increased by 0.005.
3. Elastic-plastic analysis under rare earthquakes shows that the damping ratio is 0.05.
How thick is the masonry wall of a single-storey factory building?
In single-storey industrial factory buildings, masonry walls generally only play a protective role, except when the span is less than 15 meters and the crane tonnage is less than 5 tons.
The thickness of brick walls is 240 mm and 365 mm, and other masonry walls are 200-300 mm.