(1) medium bridges with a single span of 20m to 30m or a total span of 30m to100m (including standard overpasses and viaducts of the same span);

(2) Expressway and airport runway;

(3) roads with a red line width of more than 40 meters (including sidewalks, carriageways and isolated flower beds);

(four) tunnels (including underground passages) and civil air defense projects that implement municipal quotas;

(5) Double-row or multi-row closed culverts of various structures, single-row closed culverts of concrete structures with cross-sectional width exceeding 1.5m or brick-concrete structures with width of 2m or more;

(6) diameter >; 1200mm rainwater and sewage drainage pipe;

(seven) sewage treatment plants and water purification plants, rain sewage pumping stations, water plants with a capacity of 50,000 tons or more;

(8) Urban earth dikes and concrete flood control structures.

The second category:

(1) medium and small bridges with single span 10~20m ~ 20m or total span 15 ~ 30m (including standard overpasses and viaducts of the same span);

(2) Roads with red line width of 3 1~40m ~ 40m;

(3) Single-row closed culvert with cross-section width 1.5m or brick-concrete structure less than 2m;

(4) Rain and sewage drainage pipes with a diameter of1001~1200mm;

(5) Water plants with a capacity of less than 50,000 tons;

(six) other urban flood control structures except concrete structures and earth dikes.

Three categories:

(1) Small bridges with single span less than10m or multi-span total length less than15m, and standard overpasses and overpasses with the same span;

(2) Roads with red line width of 2 1~30m ~ 30m;

(3) Rainwater sewage drainage pipe with a diameter of 501~1000 mm. Category IV: (1) Bridges and culverts with single span less than 5 meters or multi-span total length less than 8 meters;

(2) Roads with red line width ≤20m;

(3) Rainwater and sewage drainage pipes with a diameter of ≤500mm or less;

(4) Concrete and brick cable trench.