BUILDING THE OHIO RIVER BRIDGE

[Music] stru one of the largest and with allies M plant fabrication capacity offers a unique follow through most advantageous to CL Louisville Allied entered the competition this bridge was to be unique in that it was to become one of the few all welded truss bridges in the country and the largest to date Allied was awarded the contract on its low bid this film is a record of how that contract was fulfilled the job Kentucky and Jeffersonville Indiana over the Ohio River to construct this bridge from start to finish was now alignment a challenge requiring answers in advance to a multitude of questions not yet asked solutions to all the problems of stresses strains and strength fabrication planning at Allied has the advantage of the close collaboration of its Construction Division whose Representatives advise and recommend according to the needs of erection techniques and conditions here in the fabrication planning stage the schedule is Thoroughly determined and the procedure specified which components to be handled at which plant by what personnel and with what equipment since this was to be Al Li's first all welded truss Bridge job new equipment had to be purchased and unique preparations made by contract all welding technicians had to be qualified by test and checked out every 6 months the investment in Personnel training ran into thousands of dollars before Bridge component production could commence while many different types and shapes of structural steel components were to be fabricated this film will limit its review of fabrication detail to a cord member and a floor beam the steel to be fabricated is delivered from the steel mill to specified size and thickness each piece by shop order has its particular place in the bridge structure and is given an item number by which it can be moved into the shop in proper sequence this number is assigned by the materials Control Department which allocates the pieces to be used for each component there are four different types of Steel in this incoming steel order and these are identified by color coating the color painted on the edge of the plate signifies the type of Steel a new heat treated steel is being used in the fabrication of a considerable number of the trust members for the Louisville bridge this is a special quenched and tempered steel permitting drastic weight reduction while offering the strength toughness and weldability required in Bridge construction the fabricating floor in the Hammond shop has a particularly good layout the bay in which the cords are fabricated is 1150 ft long requiring 11 moves in the progress of steel plate through layout flame planing fitting welding trimming Drilling and Milling in the course of completing a cord member for the bridge the steel plates for the cords come from the mill in 4 lengths and in multiple widths since the finished cord is 70 ft long two plates must therefore be laid out and welded together the end of each plate is prepared for the weld By Flame cutting the edges to a 30° angle [Music] when the beveled ends are buted together a 60° V is formed to take the butt well [Music] here is the most critical phase of the component fabrication the weld The Joint must be completely fused to provide 100% joint strength strength equal to that of the steel up to 135,000 lb per square in Ultimate tensil strength a requirement of the contract it was met with automatic submerged AR welders using mild steel wire and and a special alloy flux to meet the composition requirement of the basement and the speed of travel of the machine are very critical and must be carefully controlled and closely supervised after multiple passes have filled the V groove the joined plate is turned [Music] over the joint is gouged out down to sound welled metal with a carbon Arc High amperage is required to melt the metal which is blown out by compressed air the gouged joint is filled in with weld up to slightly above the surface level of the plate [Music] the weld is then ground down flush with the plate surfaces the two plates have become one although every precaution and the best in materials techniques and technicians have been employed no assumption that a perfect weld has been made is accepted 6,000 X-ray pictures were made on this specific fabrication job each picture must be cleared before proceeding with the fabrication no cracks no paracity No Lack after the welding is approved the plate is moved to the flame planer the original plates are ordered from the mill in multiple widths not only to reduce handling but also to ensure straight edges here in a single operation the plate is cut into and trimmed multiple torches are operated simultaneously to maintain accuracy and to reduce the possibility of distortion a pantograph burning machine machine is used to cut out the manholes in the plates the manholes are incidental openings cut into the top Center and bottom cord panels to lighten the steel member to facilitate access for painting and make maintenance easier the manhole to be cut is outlined by a black line on a white template this is traced by the patag graph's electric eye as it cuts through the steel this multich machine is equipped to cut four holes in a single operation the flanges of the cord our first blast cleaned along the center line of the flange plate to ensure clean surfaces for weld Fusion after both flange plates are blast cleaned they are set into the first fitting fixture one on either side of the center web plate here they are squeezed together so that the three plates form an H section when the plates are squeezed to final position they are tacked the H section is then turned over and Tack with on the other side in press operation for the [Music] welding the H section now a fifth chord is moved to the welding fixture the w in is done by automatic submerged arc welders which are set and started by the operator note that the arc is not visible because it is completely submerged by the flux because of its superior quality and penetration automatic submerged arc welding is preferred and was a requirement of this bridge contract after the fillet welds have been made and inspection cleared the welded H section is moved to its final fitting position the cover plates with the manholes cut into them are here fitted into position to form the rectangular box shape of the cord member here Fitters carefully line up the plates in preparation for tack [Music] welding the fitted cord is then set up in its final welding position the Cradle of the final welding fixture is designed to to hold the cord in a diagonal position this places the V formed by the joining plates in an upright position and facilitates the welding the final welding is done with a submerged arc welder on a manipulator the machines are closely watched by the welders who take great care to control the quality of the weld by following the required procedure the welding of the closed cord joints is done in a predetermined sequence to counteract stress and to guard against distortion the cord now completely welded into a steel box is laid out on the floor where the trim lines center lines template number and location are marked on by the layer up the excess metal is trimmed off by a flame cutter to the trim lines at the drilling position the designated template is attached to the plate and under siiz bolt holes are drilled with radial drill presses [Music] the last move before the cord leaves the shop is to the beam milling machine here the ends of the cord members in compression are milled to the exact Dimension indicated by the marking ensuring a good snug fit in both assembly and subsequent erection every fabricated member must conform to the drawings and specific before it is permitted to leave the shop this cord has passed inspection so it gets its yellow ticket to the assembly yard each completed trust member is taken to the assembly yard to be assembled into its actual position in the completed structure proper alignment of the members is made according to the drawings and specifications to ensure accurate fit up for Fe Direction the fabricated members are laid out according to their position in the bridge design the connecting gusset plates are positioned and attached to the trust members with shot bolts alignment is then made with a Transit using the geometric angle specified by the drawings when the alignment is confirmed the undersized holes are enlarged to proper size by [Music] reing after the required number of panels for the trusses have been assembled and reamed they are disassembled after disassembly the trust members are move to another area for high strength [Music] bolting the gusset plate is first removed for deburring deburring of all contact surfaces is done to ensure an absolute surfac to surface contact this is a requirement for high strength bolting the gusset plates are delivered to the erection site already attached to joining members attachment is made by the installation of permanent high strength bolts the size of the bolts required is specified by contract all bolts must be brought up to their required torque to make sure of getting proper bolt tension all air impact wrenches are calibrated twice each 8-hour shift according to contract all corrosion loose scale and dirt must be removed before painting although not required by contract Allied feels the most efficient cleaning method is blast cleaning for a better quality job the shop prime coat of paint 3,300 Gall of it were used on this project is specified and brush painting was required for this particular job the techniques of floor beam butt welding gouging grinding are similar to those for cord member plates the floor beams being 96 ft in length are made up of two 48 ft web plates the butt welding of the web plates is done in single widths because the floor beams for this particular job are 9 ft deep again x-rays are made to ensure perfect welded joints when the butt welding is finished the 96t length is laid out in accordance with specs and trimmed to the proper camber width and shape both plate edges are trimmed simultaneously the fixed flame cutter on the right is trimming a straight line Edge because the trim line along the left Edge is angular an operator guides the flame cutter there the fabricated flange plates are now joined to the web plate in the fitting jig a white chalk line helps the operator position the flange plate for fitting to the web plate hydraulic jacks in the fitting fixture squeeze the flange plates into position working out from Center fitting first one then the other the floor beam is tack welded in preparation for the welding and is removed from the fitting fixture the floor beam is now placed in The Jig of the giant panurus welding machine this huge automatic submerged arc welder is one of the first machines in the country ever to be installed for all welded girs two tandem arc welding heads using 3,000 amps weld the top and bottom flanges to the web at the same time to complete the welding the floor beam is rolled over and welded similarly on the other side any width from 39 in to 13 ft can be welded in this manner but the machine can also be used for various other setups it can operate at rates up to 40 in a minute steel stiffeners are installed to add strength and to avoid web buckling the number to be used is determined by the need according to the calculated stresses on the members reinforcement of this kind is custom fit for each occasion considerable skill is required to create a tight fit without excessive grinding or welding because of the limited space stiffeners are welded by the manual shielded metal Arc [Music] method is a heavy load weighing anywhere from 22 to 40 tons consequently to save a move it is sometimes possible to perform more than one operation in the same [Music] location here without moving the floor beam after trimming the holes for the end connections of the floor beam are laid out and drilled and the connection angle is attached [Music] since no assembly is done in the plant yard with floor beams the final high strength bolting of the connection angles is done at this location to the required specification when the finished floor beam is blast cleaned and painted it is loaded on a truck for its trip to the barge which waits for it in Chicago's Calumet Harbor 71 floor beams and 1100 cord members were planned scheduled and delivered in [Music] this at the harbor the fabricated members are loaded in proper erection sequence to begin their 3-we trip by barge to the erection site at Louisville Kentucky delivery from Chicago can be made to any area in the world by water leaving calat Harbor the barge route follows the Illinois River enters the Mississippi at Grafton and proceeds to Carol here the barge enters the Ohio river and moves Upstream to Louisville a Steel Bridge of this size is a big idea a tremendous structure big in every way fabricating the big pieces of this 11,000 ton steel puzzle is one thing requiring highly specialized skills and Equipment as we have seen 4,000 tons were fabricated before erection ever began putting the pieces together is another matter requiring a big Diversified experienced organization with a wide variety of equipment and plenty of ideas inventiveness and Ingenuity to complete the project most economically but with these and the cooperation of the fabricating shop the erection problems are always solved the temporary false workor used on this job was also fabricated of Steel in Allied shop steel piling which had been driven into Bedrock making it very stable and [Music] safe as the bridge members are delivered to the job in proper erection sequence no motion is lost getting them into place the heavy floor beams in balance with their special pre-drilled hitches lift easily iron workers operating as high as 150 ft above the water team up with the ground crew to jockey the cords and other members into place their tools are muscle malls wrenches and chain hoists their Creed is always safety once a week a so-called toolbox meeting is held to talk over safety and to point out any potentially dangerous conditions [Music] cord by chord and member after member the bridge begins to resemble the specified [Music] silhouette when the pre-drilled holes line up the connectors insert tapered drift pins and Hammer them in to line the pieces up exactly here it is that the planning and the preit prove their worth this is where the collaboration of fabrication and construction Personnel pays off this is the final engineering test of all of the planning and calculation now the bolt up Crews come along putting high strength bolts into the remaining holes and replacing drift pins using air powered wrenches they add another 150,000 field bolts to the 60,000 shop bolts already installed this big Derek Tower was designed and built especially for this job it's supported by two barges tied together the tugs are part of the construction division's Mobile equipment inventory the special unloading crane gets an assist from the Derek to lift one of the two heaviest cord members in the bridge weighing 43 tons each the steel of which the bridge members are fabricated is so hard and tough that pipe softeners and heavy rubber belting are used to prevent the chokers from sliding and the lines from being cut into two as the bridge grows the practicality of the design consideration of materials fabrication handling and erection problems becomes more and more evident and significant many of the members are fabricated with calculated curvatures anticipating the traffic and dead load which will straighten them under function the whole structure is designed to withstand a constant wind force of over 100 [Music] mph sometimes the answer to a given erection problem requires a little physical persuasion like shoots of growing vines the spans reach out toward their pre-arranged meeting places at closure the accuracy of deflection and stress calculations are put to rigid test here engineering knowledge and Fabrication Shop skill and the proper cambering of trusses really pay dividends the calculated deflection for this particular span half pockets in the adjoining cords have been provided in which Jacks are placed that will be used to make push and pull adjustments so the ends of the Catal lever will go together making the final closure is an important event in the life of a bridge its birth this is an idea transformed into an 11,000 ton reality an achievement according to plan an all- welded steel six Lane highway bridge lighter in weight more economical requiring less maintenance a structure of functional strength and appearance deliver a bridge the contract said and so Allied proudly adds its first all welded structural steel truss bridge to other examples which so clearly demonstrate its fabrication power plant in Florida a coffer Dam in Indiana a ballpark in Minnesota a highrise building in Chicago this is the work of the Allied structural Steel company