cartman
06-08-2006, 07:38 PM
Jon, I forget if you work with TV, radio, or both. Were either of these stations your clients? There are some great pics of the carnage in the link.
hxxp://www.wirelessestimator.com/t_content.cfm?pagename=Demolition
Broadcast tower collapse topples sister structure in Georgia demolition attempt using explosives
June 7, 2006 -
What appeared to be a newly written textbook example of how to demolish a 1,000-foot-tall broadcast tower that had interlaced guy wires with another 1,000-foot tower less than 150-feet away, turned into a catastrophe this evening when both towers collapsed during the demolition.
Controlled Demolition, Inc. of Maryland had been contracted to remove the WFXL-TV broadcast tower in Doerun, GA after it had been structurally damaged after an Army Chinook helicopter crashed near the top of the guyed tower last Thursday, killing four servicemen.
Four days of extensive engineering and equipment planning preceded today's demolition. Eighteen explosive charges had been placed on the tower's north nine guy wires so that the structure would fall to the south aided by the momentum of a 6,800-pound antenna that was already leaning 60-inches in that direction.
Cordoned off almost 2,000-feet from the towers, cameramen, reporters, technicians assisting CDI in the tower felling, and a handful of residents of this small South Georgia farming community of less than 900 people eagerly awaited the WFXL-TV tower's collapse. (View Video )
Demolition team members positioned themselves just outside the tower's fall radius at 1,100-feet where they would use equipment that would send an electrical charge to ignite the plastic explosives.
As the countdown began, reporters prepared their story's lead, camera operators zoomed in to capture both tall structures and CDI employees and others assisting them embraced the excitement of the moment, knowing that they would accomplish a mission few people in the world would even take on.
Spectators saw dark billowing clouds appear on multiple locations of the tower's north guy wires followed by the powerful sound of simultaneous explosions that rocked the area. The tower remained upright momentarily, and then began a rigid fall south to open fields as planned.
Then it was apparent that something had gone terribly wrong as the tower bent almost ninety degrees at approximately the 360-foot level with the remainder of the structure beginning to fall vertically and slightly to the north.
Then WFXL's sister structure began to collapse vertically. WFXL's tower was on the ground within 15 seconds; 12 seconds later WALB's broadcast tower was intertwined in tons of twisted steel.
WALB's news anchor Dawn Hobby was shocked. Staring at the industrial carnage quickly disappearing under clouds of dust, she paused for a few seconds stating, "We are all a little stunned. We did not really expect to see both towers come down like that."
Workers assisting in the demolition project shook their heads in disbelief.
Professionals who have reviewed WALB's footage and other videos believe that the top guy wire on the WFXL tower was severed correctly by an explosive charge, but as the tower began to fall the wire curlicued around the top guy wire of the Radian tower, riding it down and preventing the top section from falling to the south as planned.
The top of the WFXL tower then proceeded to collapse almost vertically for a short period of time with the very top of the structure falling horizontally in a slight northern direction.
Initially, it appears that WALB would have been spared had WFXL's last two or three feet of its antenna not struck the fourth guy wire of the Radian tower. The shock loading to the structure reportedly caused a major catastrophic failure of a leg and/or bracing and the tower began to telescope upon itself, reminiscent of the Twin Tower collapses, aided by a heavy 20-foot colocation platform without tenants.
No injuries were reported following the 6:32 p.m. accident.
Safety issues turned salvage operation into demolition project
According to R. David Stiles, president of ProCom Towers International, Inc. of Tennessee, the station's 6,800-pound antenna would have had to be removed before it would be safe for tower maintenance workers to provide temporary guying support to replace a radial guy that was sheared during the crash.
However, Stiles said that helicopter companies related that it was too dangerous for them to provide the aerial services required.
Stiles, who has been involved in the successful felling of ten towers, coordinated the services of CDI to demolish the structure by collapsing it in an open field by using strategically placed explosive charges. Although numerous tower erection companies have felled towers over the years by supervising a local blasting contractor, WFXL's structure created a unique safety concern.
WALB-TV's guyed tower sat approximately 150' away from the WFXL structure and was in danger of collapsing if the WFXL tower were to fall into it or across its supporting guy wires. Both towers are owned by Raycom Media of Montgomery, AL.
CDI President Doug Loizeaux has designed and managed some of the world's largest implosions, but his attention to detail on the Georgia tower felling, Stiles said, was truly professional. He said that the charges "cut like butter" and the plan worked perfectly. "Unfortunately, the one guy wire wrapped itself around another one," he explained.
Loizeaux had set up a system of temporary guys on the bottom of the tower and at the 60-foot level using ¾" IWRC strand to secure the bottom of the tower to the southeast and southwest inner anchors so that it would not kick back to the north toward the equipment building when the north guy wires were severed.
The world-renowned demolition expert said that he thought "the tower may likely lay out almost at its full height."
The tower was not set in the concrete foundation, but rested on top of it, being held in place by the structure's weight and the compression of the guy wires' tension. It was centered upon a short pier pin that allows slight rotation when severe wind conditions provide excess torque upon the tower.
Interlaced guy wires on WFXL's north anchor complicated the tower's demolition. To ensure that they did not foul WALB's guy wires when WFXL's wires were released, shaped charges encased in hinged PVC were hoisted up the guy wires using a pulley system. An additional charge was placed at the base of each guy wire as well.
Eighth level charge placement might have contributed to failure
By moving as far back as 1,000-feet from the tower, technicians were able to place the charges at appropriate levels. The eighth level guy charge may not have been at the ideal height since it was impossible to create a leveraged pull up the wire and other attachment procedures would have been too dangerous.
The tension from the remaining southeast and southwest guy wires was expected to pull the tower to the south with a momentum assist from the 3-1/2-ton broadcast antenna and the tower itself that was leaning 60-inches to the south as a result of the crash damage.
Test blasts under the direction of Loizeaux were made yesterday upon guy wire and turnbuckles to assess the proper charges that would be required. He also adjusted the tension on some of the guys on the southeast and southwest anchors of the tower.
Stiles had flown a crew in today that he had working in Puerto Rico to assist in inspecting the WALB tower once the WFXL structure was successfully felled. Instead, tomorrow morning they will be helping to assist in the removal of both towers.
Both stations are operating from temporary transmitters in Albany, GA. An estimate regarding the replacement cost for both structures is unavailable.
hxxp://www.wirelessestimator.com/t_content.cfm?pagename=Demolition
Broadcast tower collapse topples sister structure in Georgia demolition attempt using explosives
June 7, 2006 -
What appeared to be a newly written textbook example of how to demolish a 1,000-foot-tall broadcast tower that had interlaced guy wires with another 1,000-foot tower less than 150-feet away, turned into a catastrophe this evening when both towers collapsed during the demolition.
Controlled Demolition, Inc. of Maryland had been contracted to remove the WFXL-TV broadcast tower in Doerun, GA after it had been structurally damaged after an Army Chinook helicopter crashed near the top of the guyed tower last Thursday, killing four servicemen.
Four days of extensive engineering and equipment planning preceded today's demolition. Eighteen explosive charges had been placed on the tower's north nine guy wires so that the structure would fall to the south aided by the momentum of a 6,800-pound antenna that was already leaning 60-inches in that direction.
Cordoned off almost 2,000-feet from the towers, cameramen, reporters, technicians assisting CDI in the tower felling, and a handful of residents of this small South Georgia farming community of less than 900 people eagerly awaited the WFXL-TV tower's collapse. (View Video )
Demolition team members positioned themselves just outside the tower's fall radius at 1,100-feet where they would use equipment that would send an electrical charge to ignite the plastic explosives.
As the countdown began, reporters prepared their story's lead, camera operators zoomed in to capture both tall structures and CDI employees and others assisting them embraced the excitement of the moment, knowing that they would accomplish a mission few people in the world would even take on.
Spectators saw dark billowing clouds appear on multiple locations of the tower's north guy wires followed by the powerful sound of simultaneous explosions that rocked the area. The tower remained upright momentarily, and then began a rigid fall south to open fields as planned.
Then it was apparent that something had gone terribly wrong as the tower bent almost ninety degrees at approximately the 360-foot level with the remainder of the structure beginning to fall vertically and slightly to the north.
Then WFXL's sister structure began to collapse vertically. WFXL's tower was on the ground within 15 seconds; 12 seconds later WALB's broadcast tower was intertwined in tons of twisted steel.
WALB's news anchor Dawn Hobby was shocked. Staring at the industrial carnage quickly disappearing under clouds of dust, she paused for a few seconds stating, "We are all a little stunned. We did not really expect to see both towers come down like that."
Workers assisting in the demolition project shook their heads in disbelief.
Professionals who have reviewed WALB's footage and other videos believe that the top guy wire on the WFXL tower was severed correctly by an explosive charge, but as the tower began to fall the wire curlicued around the top guy wire of the Radian tower, riding it down and preventing the top section from falling to the south as planned.
The top of the WFXL tower then proceeded to collapse almost vertically for a short period of time with the very top of the structure falling horizontally in a slight northern direction.
Initially, it appears that WALB would have been spared had WFXL's last two or three feet of its antenna not struck the fourth guy wire of the Radian tower. The shock loading to the structure reportedly caused a major catastrophic failure of a leg and/or bracing and the tower began to telescope upon itself, reminiscent of the Twin Tower collapses, aided by a heavy 20-foot colocation platform without tenants.
No injuries were reported following the 6:32 p.m. accident.
Safety issues turned salvage operation into demolition project
According to R. David Stiles, president of ProCom Towers International, Inc. of Tennessee, the station's 6,800-pound antenna would have had to be removed before it would be safe for tower maintenance workers to provide temporary guying support to replace a radial guy that was sheared during the crash.
However, Stiles said that helicopter companies related that it was too dangerous for them to provide the aerial services required.
Stiles, who has been involved in the successful felling of ten towers, coordinated the services of CDI to demolish the structure by collapsing it in an open field by using strategically placed explosive charges. Although numerous tower erection companies have felled towers over the years by supervising a local blasting contractor, WFXL's structure created a unique safety concern.
WALB-TV's guyed tower sat approximately 150' away from the WFXL structure and was in danger of collapsing if the WFXL tower were to fall into it or across its supporting guy wires. Both towers are owned by Raycom Media of Montgomery, AL.
CDI President Doug Loizeaux has designed and managed some of the world's largest implosions, but his attention to detail on the Georgia tower felling, Stiles said, was truly professional. He said that the charges "cut like butter" and the plan worked perfectly. "Unfortunately, the one guy wire wrapped itself around another one," he explained.
Loizeaux had set up a system of temporary guys on the bottom of the tower and at the 60-foot level using ¾" IWRC strand to secure the bottom of the tower to the southeast and southwest inner anchors so that it would not kick back to the north toward the equipment building when the north guy wires were severed.
The world-renowned demolition expert said that he thought "the tower may likely lay out almost at its full height."
The tower was not set in the concrete foundation, but rested on top of it, being held in place by the structure's weight and the compression of the guy wires' tension. It was centered upon a short pier pin that allows slight rotation when severe wind conditions provide excess torque upon the tower.
Interlaced guy wires on WFXL's north anchor complicated the tower's demolition. To ensure that they did not foul WALB's guy wires when WFXL's wires were released, shaped charges encased in hinged PVC were hoisted up the guy wires using a pulley system. An additional charge was placed at the base of each guy wire as well.
Eighth level charge placement might have contributed to failure
By moving as far back as 1,000-feet from the tower, technicians were able to place the charges at appropriate levels. The eighth level guy charge may not have been at the ideal height since it was impossible to create a leveraged pull up the wire and other attachment procedures would have been too dangerous.
The tension from the remaining southeast and southwest guy wires was expected to pull the tower to the south with a momentum assist from the 3-1/2-ton broadcast antenna and the tower itself that was leaning 60-inches to the south as a result of the crash damage.
Test blasts under the direction of Loizeaux were made yesterday upon guy wire and turnbuckles to assess the proper charges that would be required. He also adjusted the tension on some of the guys on the southeast and southwest anchors of the tower.
Stiles had flown a crew in today that he had working in Puerto Rico to assist in inspecting the WALB tower once the WFXL structure was successfully felled. Instead, tomorrow morning they will be helping to assist in the removal of both towers.
Both stations are operating from temporary transmitters in Albany, GA. An estimate regarding the replacement cost for both structures is unavailable.