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Men in the work platform are equipped with radio headsets, which, according to Troy Carter, provides one of the most important tools on the project: communication. Bridge job minus the cranes: Older structure & creativity conquer lifting obstacles By Peter Hildebrandt Cranes and the wire rope they depend on are instrumental on countless construction sites. Lifting of tremendous loads to heights unobtainable in any other way can be done with relatively little effort aside from the forces placed on the crane equipment and wire rope cables designed for such work. But as crane operators will also explain, safe use of equipment, safety for workers on the job and protection of nearby pedestrians, residents or those taking part in area recreational activities is the chief concern before works even starts. C onstruction of a new bridge across the Catawba River on U.S. Highway 21 presented challeng- es which could easily have compromised safety. This route starts at Hunting Is- land on the Coast of South Carolina and runs north to Wytheville, Virginia. The current bridge, two thirds up the length of this highway has served motorist well over the years since it first opened in the 1940s. But a new bridge being built across the Catawba River involved construction in a different environment than the one found during the building of the first bridge. Canoeists and kayakers now regu- larly paddle the waters just below the bridge while increasing traffic in the area demands that work proceeds quickly and efficiently as possible. The riverbed is full of loose rocks and a solid rock bottom in some parts. An upstream hydroelectric dam raises and lowers water levels periodically, de- pending on the needs of the area elec- tric utility company which owns the dam — or demanding river buffs. The standard method REA Construc- tors, Inc. considered for building the new bridge involved cranes and barges to carry the cranes operating while down in the actual Catawba River, according to Troy Carter, project manager with REA Constructors, Inc. (now also a part of the Lane Construction Company). The tower before the work platforms were in were in the barges. But when cranes have the girder on and start to go, there can be a lot of uncertainty." Using barges they would have been setting beams down and had situations of uncertainty and constantly trying to catch up. Dry runs were done with large cranes and equipment had to be moved in leap frog fashion with cranes being repositioned multiple times. Places for the beams to be set down had to be worked out. Using barges most likely would have damaged a lot of barges too. "REA Con- tracting owns about 40 barges," ex- plains Carter. "But it would have taken about 100 barges to do this job. We would have had to either buy or rent those extra barges and rental com- panies in this area would charge us to fix them if they get any damage to the bottom of their barges with the rocks puncturing or denting the bottom. They place the barges on a device, rotating them and inspect with a flashlight; it can cost up to $15,000 to fix a barge. We would have had barges all the way continued on page 10 "When you're in the water with the crane in a barge, the varying depths of the river bottom mean the barge's bot- tom will be on the rocky bottom due to water displacement at certain points in the river. Adding the weight of the girder means the barge will go down the exact volume of water that the beam weighs. The drillers of the bridge's foot- ings knew their exact weight when they place.

Bridge job minus the cranes - Award Winning OZ Lifting ... job minus the cranes: Older structure & creativity conquer lifting obstacles By Peter Hildebrandt Cranes and the wire rope

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Men in the work platform are equipped with radio headsets, which, according to Troy Carter, provides one of the most important tools on the project: communication.

Bridge job minus the cranes: Older structure & creativity conquer lifting obstacles

By Peter Hildebrandt

Cranes and the wire rope they depend on are instrumental on countless construction sites. Lifting of tremendous loads to heights unobtainable in any other way can be done with relatively little effort aside from the forces placed on the crane equipment and wire rope cables designed for such work. But as crane operators will also explain, safe use of equipment, safety for workers on the job and protection of nearby pedestrians, residents or those taking part in area recreational activities is the chief concern before works even starts.

C onstruction of a new bridge across the Catawba River on U.S. Highway 21 presented challeng-

es which could easily have compromised safety. This route starts at Hunting Is-land on the Coast of South Carolina and runs north to Wytheville, Virginia. The current bridge, two thirds up the length of this highway has served motorist well over the years since it first opened in the 1940s. But a new bridge being built across the Catawba River involved construction in a different environment than the one found during the building of the first bridge.

Canoeists and kayakers now regu-larly paddle the waters just below the bridge while increasing traffic in the area demands that work proceeds quickly and efficiently as possible. The riverbed is full of loose rocks and a solid rock bottom in some parts. An upstream hydroelectric dam raises and lowers water levels periodically, de-pending on the needs of the area elec-tric utility company which owns the dam — or demanding river buffs.

The standard method REA Construc-tors, Inc. considered for building the new bridge involved cranes and barges to carry the cranes operating while down in the actual Catawba River, according to Troy Carter, project manager with REA Constructors, Inc. (now also a part of the Lane Construction Company).

The tower before the work platforms were in

were in the barges. But when cranes have the girder on and start to go, there can be a lot of uncertainty."

Using barges they would have been setting beams down and had situations of uncertainty and constantly trying to catch up. Dry runs were done with large cranes and equipment had to be moved in leap frog fashion with cranes being repositioned multiple times. Places for the beams to be set down had to be worked out.

Using barges most likely would have damaged a lot of barges too. "REA Con-tracting owns about 40 barges," ex-plains Carter. "But it would have taken about 100 barges to do this job.

We would have had to either buy or rent those extra barges and rental com-panies in this area would charge us to fix them if they get any damage to the bottom of their barges with the rocks puncturing or denting the bottom. They place the barges on a device, rotating them and inspect with a flashlight; it can cost up to $15,000 to fix a barge. We would have had barges all the way

continued on page 10

"When you're in the water with the crane in a barge, the varying depths of the river bottom mean the barge's bot-tom will be on the rocky bottom due to water displacement at certain points in the river. Adding the weight of the girder means the barge will go down the exact volume of water that the beam weighs. The drillers of the bridge's foot-ings knew their exact weight when they

place.

continued from page 8 across the river, basically a 'barge road' all the way across."

The Catawba has a maximum depth of only about four feet here. They deter-mined that they had to come up with a method which did not use barges, one which would improve both the safety and the environmental impact of the project, according to Carter. With an operational bridge already in place, they wondered about systems that could use that — and bypass the use of river cranes.

The initial impetus for setting up the bridgework construction system in such a manner came from Rick Ronson, with Triplett King. Bonson was one of the project managers Troy Carter had once worked with. Bonson had retired, but Carter recalls a photo he had of a project in D.C. in which a similar setup was used.

"It was more of a makeshift thing for a couple of beams which couldn't be reached," explains Carter. "It wasn't as elaborate as what we've come up with here, but the concept was there. We looked at how that applied to this proj-ect as a possible solution to our issue of how we were going to place the beams. Then we put it forth into design and de-velopment and we got a local designer, Triple Key, to do the design for us. The decision to go with the framework sys-tem instead of barges on the river was made in October, 2010.

'With the framework setup, there is no time when an unsafe situation pres-ents itself. A crane in a barge on the river involves uncertainty. 'With one side on the rocks and the other in the water, something could unfurl itself re-ally quickly. In the method we're using now, we are bringing the beams across on the existing bridge one at a time."

When the girders come in, they come from the Charlotte or north side of the river. The truck pulls up to where the girder is needed, a hand-operated trol-ley with four sets of workers in each work bucket comes out over the road, workers hook the beam at each end onto the cables and the whole system effortlessly pulls the girder up from the back of the truck.

Two 30 ton manual hoists are used during the night work which involves the 11 girders in the span, each weigh-ing 60 tons. The method involves shut-ting the existing bridge down to any traffic other than the trucks bringing in the girders; one truck with one girder at a time comes onto the old bridge due to weight limits. The process takes a total of three nights, four girders the first night, four the second night and three the third night over a period of weeks.

The final two spans of the bridge will be erected with the help of a 100 ton

The tower after the work platforms were in place.

Manitowoc 222 and one lifting frame. At this point there is no involvement with barges, as this final stretch is over solid ground. A 100 ton crane is situ-ated at the upper end of the inclined bank going down to the river.

"This method is controlled," says Carter. "When you watch it, it's almost boring. But it's safer, less expensive; we're putting beams in place without any cranes on barges in the water.

"On the two cranes we are using, there are monthly inspections. Any time there are any deficiencies in the wire rope, it is replaced according to how many breaks per lay are found in the wire rope cable. Anytime we have a problem with our wire rope we replace it right away.

The girders are being launched from the old bridge but the system itself mounts to the caps of the new bridge. This system cantilevers out over the old bridge; they hoist the girder up from the waiting truck and then workers walk the beam into place. This arrange-ment mounts to the cap and the column - the substructure itself - instead of the conventional erection method using a crane. The new substructure is utilized as its support, eliminating the need for a mobile crane or a crawler crane.

The cable-winch system allows things to be pulled ahead in increments. Rela-tively small winches are used to avoid carrying around big pieces of equip-ment, according to Emilio Valentin, REA Contracting project superinten-dent. Valentin set up a PowerPoint presentation clearly illustrating how this particular system that he largely developed himself, based on the initial ideas of Bonson, would be set up. He used a Google program to design ex-actly how the rigging and framework would look and work.

"They needed to be moving around something that's fairly heavy with a system that doesn't really take much weight either," explains Valentin. "So what we came up with involving this one-half section in theory takes 3,000 pounds of pull to move it forward. You don't need much to pull it. But we al-ways put a little bit more in there just

in case, so if one come-along fails while you're pulling, you're not stuck. Once that frame gets into position, then there is a piece on the bottom that we've got to tie up and secure the lift-ing equipment to."

The frame is designed for the substruc-ture of the bridge, so a lot of the same anchor points used for form work dur-ing the construction phase are used for anchor points on the permanent struc-ture of the bridge. The through-bolts go through the columns, yet a piece remains separate. Tie rods stay above the cap, let-ting the whole thing move ahead.

The actual come-along itself is all chained to the system and they've rigged it so that it's operable with a hand drill, enabling the chains to go up and down and the trollies to be oper-ated too. "Everything is done by hand," says Carter. "There are no mechanical parts involved in the lifting of these 60-ton, 120,000 pound concrete beams."

"For the movement of the chains to lift the beams, I adapted a handheld drill so that with the movement they cause, we essentially automated the manual hoist for the lifting and lower-ing of the beams," adds Valentin. "For the two trollies that travel back and forth at the ends of the beams, this is a motion that must stay in sync. If this system gets out of square the forces on the two towers are incredible. For this reason, we are in constant radio contact with the workers involved in the action of moving the girders into place."

Nothing as high-tech as lasers are used to keep the beams and the trol-ley system square, instead, landmarks - such as the bridge itself, by looking down - are used. The old bridge is ex-actly parallel to the new bridge. There are also marks on the frame as well as open radio communication from the op-erators on the one tower to the opera-tors on the other tower. A third person also watches and gives suggestions to each of these two towers they're get-ting behind. With an open radio chan-nel and headset system for all involved with the project, everyone is able to hear comments from everyone involved in the work and act accordingly.

"Though this system is catering pri-marily to this job, this system can be used on other jobs as well when there is limited access and you are over a waterway," says Valentin. "Other set-ups work things the other way around, launching components such as the con-crete beams, from the ends instead of along the side of the structure as is being done here. This is an especially good setup for working along an exist-ing structure from which you can take parts and equipment, in this case, the

continued on page 12

10 Wire Rope News & Sling Technology August 2012

Eleven of these girders, each weighing 60 tons, were used for the bridge span.

continued from page 10 old bridge that's already in place."

Cranes could have done the work had the river bottom environment been more cooperative. "But I like the sys-tem," adds Valentin. "It's proven that we can set a girder as fast if not faster than with just regular cranes."

When the beams come on the frame there are no worries, according to Cart-er. "When it's hooked off I have not one single concern because that chain fall system has so many protection systems built into it that this system will not let it unravel. There are multiple factors of safety there with the chain system; when the frame has the beam, I'm not con-cerned — that beam's not coming down.

"We had a pretty stiff challenge fill-

ing in all the material on the banks of the river beside the bridge, doing all the dirt work and closing the whole project in. On each river bank our Triple 2, 100-ton cranes perform what work they can accomplish from their positions. These are used to move the frame ahead. The frame comes apart in three pieces."

Oz Lifting Products supplied many of the materials including chain hoists. Distributors of their products are in the area, though the products are available across the country. They used two 30-ton gear beam trolleys for the 60-ton beams being installed. "In theory all you needed was one trolley," adds Valentin. "But be-ing that the trolley runs on the frame girder, the weight needed to be dis-persed; with all the weight on one trolley it would have deformed the equipment."

The hoists are chain hoists driven by chains moved by hand or with the hand drills. Everything is chain-driven. The small hand drills used were powered with 110 AC. They were plugged into an onsite generator. It was determined that battery-operated drills would have been too much trouble to use. All the drills were doing was spinning the chains; as the drill spins it brings the chain up, simply and safely, akin to the chain hoists which may be seen in a mechanic's shop.

"If we'd hooked up a chain hoist that

was too small for the job it never would have been able to pick the beam up in the first place and would have slipped like a clutch," says Valentin.

"The reason I went with off-brand inexpensive wenches was that this al-lowed us to have four winches instead of two or three. We had over-capacity which both increased the life of the winches and in the case of something breaking down we were covered with backup support.

"After we put the first beams in place we worked out the best way to run the system using pulleys run by drills — basically the same concept as the turning of the wheel of a bicycle using a chain. Though a simple, easily-run system these chains, wenches, hooks and hand drills got the job done do-ing a lot of heavy lifting."

The existing bridge will be dismantled and the remainder of the structure de-molished. Care must be taken due to a gas pipeline which runs parallel to the existing bridge and will be kept in place when the new bridge is completed.

With all of the high tech construction gadgets on sites nowadays, few motor-ists would consider that all eleven 60-ton girders now holding their cars above the Catawba River were easily moved into place with hand-powered pulleys moving strands of chain along with some help from a few handheld drills. INN

12 Wire Rope News & Sling Technology August 2012

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The availability on the 30T hoists that OZ provided (not once but, twice) in conjunction with the effort expended working with the customer directly to insure they were getting what they needed was impressive. In 17 years in this business, I've NEVER seen tech support like that from ANY vendor. C.W. Certex North Carolina
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