Fourteenth Street Bridge, Spanning Chattahoochee River, Columbus

Source document Quoted word for word from HAER GA-61. Not written, edited or summarised by this site.

This bridge is significant in the areas of transportation, 1ocal hi story, and engineering. It is the fourth of a series of bridges located at this site since It is significant from an engineering standpoint because it utilized existing piers of the preceeding truss bridge (with new piers added between) and the existing bridge was constructed underneath the truss bridge. After completion, the truss bridge was removed, interrupting traffic only a few hours during the entire construction process.

The bridge was determined to be eligible for the National Register of Historic Places on August 19, Report Prepared by: Hal Cole Transportation Planner I Office of Environment/location Georgia Department of Transportation Aviation Circle Atlanta, Georgia Date: April, FOURTEENTH STREET BRIDGE HAER No. GA-61 Page2 The Fourteenth Street Bridge is a concrete, filled spandrel barrel vault bridge which is 719 1 in length with a 38 1 width. Of the nine arches supporting the roadway, seven are 71 1 911 in length and the two on either end adjacent to the abutments are 59 1 9 11 The remainder of the length is composed of a slab approach supported by column bents at the eastern abutment and the abutments themselves. The 26' roadway carries two lanes of traffic with 6 1 sidewalks on either side.

A poured-concrete balustrade of open, elongated arches is located at the outer edge of each sidewalk. The present bridge is the fourth of a series of bridges which have existed at this crossing since The first of these was a wooden covered bridge which was burned in during the Civil War. It had been constructed by John Goodwin and Horace King with funds from factory owners. The primary purpose of this bridge was a transportation 1ink between factories on the eastern (Georgia) bank of the river and the homes of factory workers in Alabama west of the river. The second bridge was also a wooden covered structure.

It was constructed by Horace King after the Civil War and remained in existence until At that time it was replaced by a steel bridge consisting of five 140 1 through Pratt, pin-connected trusses. The bridge accomodated a 24 1 roadway and two six foot sidewalks. The bridge had a wooden floor and had originally carried a street car 1ine, but near the end of its use street cars did not utilize the line for safety reasons. When the need for a new bridge at the crossing became inevitable, two major considerations were apparent. The first was to utilize elements of the existing bridge to the best advantage, and the second was to accomplish the construction with a minimum of inconvenience to heavy daily volumes of vehicular and pedestrian traffic.

The first issue was addressed by using the existing piers which were in good condition with additional piers between them. These piers would then accomodate construction of concrete arches under the trusses which would continue to carry daily traffic until the new bridge was completed. The process by which the bridge's construction was accomplished was intricate and complicated. Fortunately, an account of the construction r.rocess exists in the Engineering News-Record. The article, entitled 1 Bui1 ding Concrete Bridge Around An Old Steel Bri dge 11 , was written by Searcy B. Slack, an engineer with the Georgia Highway Department. Published on November 23, it is a contemporary and comprehensive account of the construction of the present bridge.

Because the engineering aspects of the Fourteenth Street Bridge's construction contribute to the historic significance of the property and because the article cannot be improved and might be diminished by any modern su1T111ary of its content, a portion of the article is included in the following text. FOURTEENTH STREET BRIDGE HAER No. GA-61 Page 3 The plan adopted required the construction of four new piers between the old piers and the counterforting of a concrete retaining wall between the cotton factories so that it would serve as the east abutment. Between the new piers and the old piers nine filled spandrel barrel arches were built and a slab approach supported by column bents connected the east abutment and the improvised abutment pier.

The west abutment was strengthened by adding a new concrete wall in front of the old abutment. The suggested method of construction set forth in the specifications was as follows: 11 In the opinion of the engineers the logical method of construction of this brid~e is as fol 1ows: Cofferdams be constructed for piers 11 D , F , 11 H11 , and 11 J 11 ; these cofferdams to be floated in place 11 11 and the piers erected therein, placing concrete through floor of the existing bridge; abutment 11 BII be constructed; bents Nos. 1 to 5 be constructed; additional concrete for abutment 11 K11 be placed. 11 The existing steel spans can be raised so that the bottom 11 flanges of the floorbeams will clear sidewalk elevations of the new bridge.

These spans can be raised by cribbing on top of the present piers and after proper height has been reached shoring from the bases of the existing piers to the bottom of the shoes of the spans leaving no crib work on top of the old piers. By raising the spans in lifts successively traffic can be maintained during this operation. After the old spans have been raised the existing piers can be cut off to the proper elevations and new caps placed. Centering for the arches can be planned so as to be supported from the fl oorbeams of the old spans. The centering for the arches can be placed and the arches concreted through the floor of the old bridge.

After the centering has been removed the spandrel walls can be built, omitting sidewalks; spandrel fil 1 s can then be made and the old bridge removed, traffic being permitted on the spandrel fill of the new bridge. The sidewalks can be constructed and one-half of the brick pavement laid, traffic can then be diverted from the spandre1 fill to the new pavement, and the bridge can be completed. The east approach span can be constructed beneath the old bridge, the first span of the old bridge being raised to sufficient height to clear the new slabs, traffic being handled to the old span by means of a short runway on grade not exceeding eight per cent. 11 FOURTEENTH STREET BRIDGE HAER No.

GA-61 Page 4 In the actual construction this method was carried out as outlined except placing bents against old piers to support the steel trusses while the piers were being cut off and capped for the arches. The method used was more satisfactory as it did not require placing bents against the piers. The central portion of the piers (about 20 ft. long) between the shoes of the steel trusses was cut down to the proper elevation and the middle 18 ft. of the new cap and arch skewbacks poured. The o1d piers were cut down by dri 11 i ng holes in from both sides with compressed-air drills. The holes were from 6 to 12-in. centers depending upon the accuracy of cut desired. The holes were feathered and wedges were driven splitting the concrete out in blocks.

After a 1i ttl e practice the crew became very expert and the necessary cuts were made with ease and surprising accuracy. Cutting out concrete from one of the old piers is shown in one of the accompanying illustrations. After the central portion of the new pier caps and skewback had set, lifting beams, consisting of two 24-in. I-beams 29 ft. long connected by plates, were cribbed up on the new concrete work. The beams were so pl aced that they overhung the shoes of the two adjacent trusses. Holes were burned through the cover-pl ates of the end posts and straps were passed around the end pins of the trusses and over the lifting beams. Four 75-ton hydraulic jacks were then placed and lifting the old bridge began. It was necessary to raise the bridge 8 ft. 6 in. at the center and 4 ft.

at each end so that the floorbeams of the old bridge would clear the extrados of the new arches at the crown. Traffic was maintained over the central part of the bridge and both sidewalks during the lifting, runways provided at each end being shifted as the trusses were 1 ifted. After the lifting was finished the lifting beams were cribbed up on the new concrete skewback, leaving the ends of the piers clear so that the old concrete could be cut down and the new cap and skewback for the arch ribs completed. The new bridge required a counterfort at the ends of the piers bracing the spandrel walls. At the ends of the o1d piers contractors en1 arged these counterforts somewhat and poured them up to a suitable height to carry the old trusses.

As soon as the concrete had set, the trusses were lowered until the shoes rested on the counterforts and the 1 ifting beams and cribbing were removed to be reused. FOURTEENTH STREET BRIDGE HAER No. GA-61 Page 5 After the old steel spans had been raised and set on the counterforts, centering for the arch rings was constructed under the old spans. The centering was supported by fastening rods to the fl oorbeams of the old trusses. These rods were wrapped with tar paper where they passed through the concrete arch ring so that they could be withdrawn as soon as the arch rings had set. To prevent overloading the old trusses the arch barrels were poured in three sections each 9 ft. wide. The downstream sections were poured first from abutment 11 8 11 entirely across to abutment 11 1<.

11 As rapidly as these sections set the centering was released and set for the upstream section. As soon as the upstream sections had set the centering was rel eased and the center section poured, completing the arch barrels. Forms for the spandrel walls, cross walls and sidewalk brackets were constructed between the arch barrels and the old trusses and this portion of the new bridge was completed. The spandrel fill was made by dumping through the floor of the bridge. A rather coarse sand with a sma 11 amount of loam was used for this fill and the material was wet down in layers as it was placed. The stone drains along the backs of the spandrel walls proved very effective in carrying off the water used for packing the sand.

When the spandrel fill was completed the floorbeams of the old bridge were blocked up on the fill and the old trusses were taken down. The spandre 1 fi 11 was then made up to the l eve 1 of the floor system and the fl oorbeams were removed, the floor and stringers resting directly on the sand fill. The old floor was cut, leaving a width of from 12 to 15 ft. directly against the upstream side of the bridge and a 9 ft. strip of the concrete paving base was poured between the edge of the old floor and the downstream curb. After this paving base had set, traffic was diverted from the floor of the old bridge to the 9 ft. base, the old flooring was removed and after setting street-car tracks the paving base was completed.

The vitrified brick paving was placed from the upstream street-car track to the upstream curb and as soon as completed traffic diverted from the downstream concrete paving base to the finished brick paving and the remainder of the brick surfacing was completed. An asphaltic filler was used in making the brick pavement. The equipment and methods used by the contractors were very well planned@ All materials were delivered by rail to a yard about 500 ft. from the east end of the bridge where FOURTEENTH STREET BRIDGE HAER No. GA-61 Page 6 they were unloaded and stored by a crane. The same crane used for unloading was also used to fill the material hoppers of the central mixing plant.

All concrete was mixed at this plant and hauled to the bridge in trucks with dump bodies and handled by chutes from the truck bodies to the forms through trap doors and holes in the floor of the old bridge. In spite of the heavy traffic over the bridge, which greatly hampered the concrete trucks. as much as 100 cu.yd. of concrete was frequently handled in a day. All drilling was done by air which was furnished by a compressor located near the east end of the bridge. Electric power was also available for lights, pumping, etc. A woodworking shop equipped with a band saw, cutoff saw, planer drill press, etc., driven by electric motor was set up near the material yard and all necessary wood work for the frame was done here.

Work in the river was done from a barge equipped with hoisting engine and stiff-leg derrick, dredging in the cofferdams being done with an orange-peel bucket. Under terms of the contract 14 days I interruption to traffic was allowed during the removal of the old bridge and laying of the paving base. By constructing a traveler, for removing the old bridge, through which traffic could pass and by cutting the floor so as to permit laying the paving base in sections, the contractors maintained traffic with only a few hours' interruption during the entire construction The di agram which i den ti fi ed the piers, abutments, etc. in the text was not included with the article. The bridge has not been significantly altered since its construction.

The roadway has been resurfaced with asphalt and the street car tracks have been removed. There are other instances in Georgi a where piers of earlier bridges were reused during replacement with modern structures. Generally however, this involved girder/beam construction. Although there are numerous other concrete arch bridges throughout Georgia, the Fourteenth Street Bridge remains as the only known bridge which was constructed using the techniques previously described. Source Cited Searcy B. Slack, 11 Building Concrete Bridge Around An Old Steel Bridge 11 , .E!i_9i n,eeri ng N e ~ 89, 21 ( 23 November : 8364A-0357A