Mo. Rev. Stat. § 231.230: Bridges costing more than forty-five hundred dollars, how built.

Whenever it shall be necessary in any township to build a bridge, the cost of which shall exceed forty-five hundred dollars, the township board of directors shall make out and cause to be presented to the county commission a certified statement of the amount of money necessary for the construction thereof, and, if deemed proper, the said county commission shall cause the bridge to be built by contract as provided by law.