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Home >> Departments/Offices >> Recreation & Maintenance >> Parks and Recreation >> Parks & Park Locations >> Haralson Mill Covered Wooden Bridge

Haralson Mill Covered Wooden Bridge

INTRODUCTION:
Built in 1997, the covered wooden bridge replaces a historic ford, which crossed Haralson Mill Road, formerly an unimproved dirt road in north Rockdale County. The bridge is immediately north of the Haralson Mill Historic District, which is eligible for the National Register of Historic Places. The setting is comprised of the Haralson Mill House, a general store, the old mill site, and a blacksmith shop. The Georgia International Horse Park, equestrian venue for the 1996 Olympic games, is located approximately six miles to the southeast of the bridge. Haralson Mill Road serves as a school bus route and is the primary north-south road in the northern one-third part of Rockdale County.

Haralson Mill Road also provides the only access to several large tracts of land, which border Randy Poynter Lake, the county's drinking water reservoir. Encompassed within the Black Shoals Park recreational area, the land to the north of the bridge is owned by the State of Georgia and is leased by Rockdale County. This land is intended for passive recreational uses by residents, to include fishing, picnicking, hiking and more. It is also home to the future Georgia Veteran's Memorial Park, which has been under construction since 2001.

Two tributaries supply Randy Poynter Lake. One of the tributaries, Mill Rock Creek, was a ford crossing approximately 20 feet wide which transversed Haralson Mill Road. Previously, the stream crossing was only a few inches deep at times and easily passable. However, with the construction of Jack Turner Dam and the impoundment of the reservoir underway, this crossing would be under water. Since the ford crossing could be under ten to 15 feet of water during certain times of the year, a bridge was preferred over a culvert due to the desire to minimize earth fills and retain mature hardwood growth in the area. Without this bridge, an area of land would be inaccessible with the road terminating on either side of the lake. This condition was not considered acceptable.

As part of the overall project improvements, Haralson Mill Road was paved and upgraded to a 35 mph design speed with a 20 mph approach to the covered wooden bridge. Although the primary traffic on the bridge is single-axle passenger vehicles, it has been constructed to accommodate multi-axle vehicles. Additionally, the bridge design incorporated walkways on both sides of the roadway to facilitate pedestrian traffic.

The bridge meets the transportation needs of the county while acting as a focal point for the historic district and utilizing the recreational areas preserved as mitigation for the reservoir's impacts.

In selecting the type of bridge, Rockdale County considered the importance of historic preservation of the area, as well as the cost factor. The wooden bridge was chosen, as opposed to the conventional concrete and steel structures commonly seen throughout the state, due to its historical significance. In order to retain the required attributes of the area, bridge designs from the early 1800's were considered.

DESIGN:
The structure emulates a covered bridge design similar to the 1820's era Town Lattice Truss design patented by Connecticut architect Ithiel Town. The bridge consists of three 50-foot spans with solid concrete piers and spill-through abutments, which have been encased with a granite veneer. The bridge superstructure is designed to utilize Georgia wood products and labor while still promoting new timber bridge technology.

Each panel is assembled with high strength bolts torqued to 700 foot-pounds. The advantage to this installation and construction procedure is a high strength stressed deck in a transverse spanned panel. This eliminates the problems associated with hydraulic jacked panels, on-site nail laminated panels, or prefabricated glue laminated panels.

The superstructure is covered by a conventional roof/truss system. The exterior framing and latticework are treated with Pentachlorophenol. The roof is tongue and groove decking with dressed cedar shingles.

SPECIFICATIONS:
Length: 150 feet (3 spans of 50 ft.)
Width: 37 feet (incl. two travel lanes & sidewalks)
Substructure: 248 cubic yards concrete & 31,000 lbs. reinforcing steel 
     - Concrete abutments with granite veneer on 
       12' x 53' steel H piles
     - Concrete beams - AASHTO Type II 
     - Intermediate concrete piers with granite veneer
Superstructure: Southern Pine & softwood
     - Chromated Copper Arsenate (CCA) treated  
        timber - 109,000 board feet
      - Pentachlorophenol treated timber - 11,000
        board feet
Deck: Stress laminated CCA treated 2" x 12" timber deck
Sides:
     - Steel column supports with timber veneer
     - Pentachlorophenol treated timber lattice and
       skirt
Roof:
     - Prefabricated wooden trusses
     - Tongue and groove decking
     - Cedar shake shingles
Miscellaneous Features: Inside lighting for security