Kitt Peak Radio Antenna
Kitt Peak Radio Antenna
How on earth does an extremely sensitive, forty foot wide scientific marvel, travel across two states, up one mountain, on roads half its width? That was the question Precision Heavy Haul, Inc (PHH) faced, when approached with transporting a 14 million dollar “Prototype Antenna”.
The Atacama Large Millimeter Array or ALMA is used for the detection and collection of data on radio sources as they operate in the radio frequency range of the electromagnetic spectrum. Antennas are usually set in an array, which upgrades their performance significantly. Locations of such objects are important as excessive amount of electromagnetic interferences from everyday objects affect data collection. The initial location from which the transport originated was the VLA or The Very Large Array site located approximately 50 miles west of Socorro, New Mexico. The final destination of the radio antenna was Kitt Peak National Observatory, 55 miles west-southwest of Tucson, Arizona, at an elevation of 7000ft. This Observatory is famous for hosting the first telescope used to search for near-Earth asteroids, and calculating the probability of an impact with planet Earth.
May 3rd, 2013 PHH received a bid request requiring a site visit on May 14th with a proposal due date of May 30th. The Reflector, at 40’ wide was going to be the widest load ever to cross New Mexico and Arizona. The pedestal with receiver cabin was going to require bridge engineering due to the additional weight being added for the required transport frame and lifting fixtures.
Precision Heavy Haul’s survey crew, which included the driver that would be assigned to the load, started immediately. Taking into account the many years of transporting in New Mexico and Arizona, PHH explored several preferred over dimensional routes that accepted 28’ wide loads.
Physically measuring widths between structures and heights for both ground and overhead clearance for the 500 + mile journey was critical for the precise planning needed for this project. The mountain portion located on the Tohono O’odham Nation presented even bigger challenges. The SR386 had one bridge and a mountain profile with a side hill cut on one side and canyon on the other. Rock outcroppings and trees lined the entire route. The final 100 feet on an even narrower access road had power lines and observatory building eves.
After encountering numerous dead ends and knowing the detail needed for the loads to safely clear all obstructions, PHH requested an extension on the proposal due date, allowing the survey crew ample time to verify a viable route. The customer granted the extension until June 13th 2013. Precision Heavy Haul submitted a thorough proposal including detailed routing, written preapprovals from New Mexico and Arizona municipalities and Arizona bridge approval with the heaviest weights given by the customer.
August 7th 2013, PHH was awarded the contract in two separate phases. The first phase which came with an issued PO included, design, engineering and fabrication with 3rd party review approval before fabrication. Phase two included all transportation including associated costs with an estimated ship schedule of the spring of 2014 at which time a PO would be issued.
As with any project, minimal tear down is always a concern. After analyzing the unit, it was preferred to be kept at two sub-assemblies which required different methods of transport. The main reflector and pedestal with receiver cabin consisted of two different dimensions and weights. Having an object of 40’ wide is challenging, especially when transport is to be conducted on mainly two lane roads. Both sub-assemblies required frames to be designed to accommodate their unique structure onto each combination of trailer. The customer provided PDF files of the main reflector as well as the pedestal, which specified important details for the design portion of the project. Both were assumed to be accurate with minimal room for any dimensional errors. A 2 to 1 safety factor was established since the starting of the project for all loading conditions of both the reflector and the pedestal.
After some analysis, the main reflector needed to be attached to the support frame by means of isolators, preventing the reflector from undergoing random frequencies produced by metal components of frame and minimizing vibrations from the transport. Structural integrity of the piece was a concern, as a bent reflector reduces its performance as well as fitment. Another factor that was considered before the design was completed was wind loading. As with an individual piece of such dimension, wind becomes an important factor. Designing a protocol took all of the previous guidelines into consideration in order to engineer a frame that will meet and exceed the multiple requirements for such reflector, including and not limited to perform under different position angles and supports.
The pedestal was heavier than the reflector by about 130,000lbs. Containing such an amount of concentrated weight increased the design process. Analysis determined the concentrated weight of the pedestal could only be supported over three points. PHH designed two identical side brackets bolted near the given center of gravity that held 87% of the weight at all times and one fabricated extension replacing the bolted pedestal foot held 13%. 108 bolts held the brackets to the pedestal. The brackets also served as securement points.
Engineering and design was a tedious process due to the components needing to be first detailed from the supplied files. The protocol for this pedestal optimized the side brackets to be used as lifting fixtures as the base lacked any of those. After extensive analysis, a frame was designed along with the several attachments that served different purposes during particular times of the transport.
Due to a dimensional conflict, the pedestal had to be set horizontally versus vertical as it is the nature in which pedestal operates. Lifting fixtures are to sustain approximately 80% of the weight at all times, and 100% during a straight pick with cranes. Several computer models were tested to accurately determine best and worst possible scenarios during transport. The frame was to accommodate and distribute over the weight over a 34ft span reducing stress concentration on the trailer. Tolerances and side bracket flatness was a concern, after fabrication unit turned out at ± 1/16”.
The engineering team felt the safest solution, was to make the fabricated lifting fixtures with extensions capable of accepting a four point pick. The lifting fixtures design ensured the main crane would have control of the pedestal, while the tail crane helped tip and achieve the horizontal position. The extensions would ensure the main crane stayed above center of gravity, restricting the pedestal from passing the center of gravity and flip through the rigging. This design provided clearance for the machined trunions to rest in the transport fixtures saddles allowing the rigging to be removed.
With the offset picking locations and trunions centered in the lifting fixture, the pedestal was able to set in the transport frame, acquiring the desired center of gravity for weight distribution and allowing the rigging to be removed. PHH felt the perimeter frame was the ideal choice because the cabin would be able to set inside the trailer, achieving minimal loaded height with adequate ground clearance.
Again, several computer models were tested to accurately determine best and worst possible scenarios for the frame to accommodate the reflector for the duration of the transport. Tolerances and frame flatness were as much a concern in the frame, as the bending moments for the lifting extensions. After fabrication, the frame turned out at ± 1/16”, falling well within the required specifications. The two crane pick worked flawlessly.
An eight line Goldhofer was selected to make the interstate journey with the reflector. The main reflector had to undergo two different transitions from being supported horizontally to tilting it 60º in order to accommodate road conditions going up Kitt Peak on a 6 line Goldhofer trailer.
A 0.125 inch tolerance between each of the support points on the support frame to the main reflector. Wind load of 8000 lbs. was calculated from ASCE velocity pressure at 35 mph wind speed. After all computations and FEA models were done, the frame was determined to meet the criteria as described. Checks were made from mathematical calculations and the FEA analysis to determine validity. Deflections seen in FEA are an estimate according to the software capabilities.
On October 2nd, discussions of a phase two accelerated schedule began. Both loads would be required to deliver by December 13th, 2013, making winter weather a main concern. Discussion with all involved team members commenced on what it would take to meet this schedule. Verifying the three month old route became a priority to allow the permit team time for submittal and conduct conferences calls with municipalities and law enforcement. Team PHH felt this tight but obtainable schedule could be met, and accepted the challenge, placing fabrication and trailer build team on a seven twelve schedule. PHH received a signed PO on October 18, 2013 for the transport portion of the project.
The route survey team was able to confirm routing and meet with state, county, and home owners, refreshing memories on how the preapproved tree trimming was going to need to take place. Some jurisdiction accommodated the loads through their own efforts, others left it to PHH’s discretion to find an experienced tree trimming professional, to cut and safely remove trimmings along busy roadways. Surprisingly most home owners were excited about the extra firewood. The total number of trees which had to be either trimmed or removed entirely through the efforts of a contractor and/ or PHH personnel was 147. Sign removal and replacement was also discussed, once again with no preferred vendor, PHH was in control. The right contractor that could meet the demands and expectations on this project was found and utilized. The timing and communication proved to be critical with the scheduling of the signs. Removal just prior to the loads arrival and replacement immediately after the loads went through. The total number of signs which had to be removed and replaced through the efforts of a contractor and/ or PHH personnel was 166. Allowing continuous travel without delays, PHH made every predetermined overnight parking area and stayed on schedule for the following day or nights law enforcement escorts.
The build team continued with the assembly of the perimeter frame installing the running gear, lighting, and plumbing for the hydraulic spread goosenecks on the trailer. Upon task completion, transport equipment and fabricated frames for this project were preloaded with approximate weights and centers of gravity to match both sub-assemblies of the radio antenna. Results of preloading were better than expected, insuring the structural integrity of all fabricated fixtures.
PHH used a total of 188,000# of test weight on the perimeter frame trailer. This exceeded the heaviest + or – scenario for the combined weight of the pedestal, lifting assembly and transport frame. Shimming adjustments took place in the trailer to achieve flatness and set the ride height. Having as much lift as possible left, while retaining the option to set the trailer on the ground, was crucial to navigate the loaded route, minimizing any need for bucket trucks. Upon confirmation of the trailers scale weights, the permit department proceeded with their portion of the project.
The build team next prepared the 6 line Goldhofer scheduled for the final stage of the project by installing a push cylinder assembly that would connect to the base of the tilt frame, and the bottom of the reflector frame. The cylinders were a simple concept but an innovative solution, eliminating several issues that would come into play without them. Once the two cranes are released from the lifting extensions, an undesired stress is applied to the tilt frames upright, the reflector could not achieve the required 60 degree angle in which all wind load calculations were based, the width increases becoming too wide to negotiate some of the rock outcroppings, and with the additional length of the lifting extensions, turning radius would be effected.
The addition of the dual acting lift cylinders allowed PHH to extend the cylinders, attach to the bottom of the carrying frame, hold the load while the cranes were released, and remove the bottom two lifting extensions. With the extensions removed, the cylinders were retracted, allowing the reflector to reach required specifications for the transport. Once the load reached the observatory the process was reversed for offloading.
The permit and project coordination team spent numerous hours on conference calls with bridge, permit and law enforcement divisions for both states. Projected overnight locations for both loads were coordinated with the correct districts ensuring personnel demands could be met. Advanced notice was critical for Las Cruces, NM. Local law enforcement and a streets and lights observer were required to escort the loads while in city limits. All municipalities agreed on the protocol being used to allow traffic to pass, sign removal/ replacement and tree trimming/removal.
Precision Heavy Haul’s staging areas coincided with the ease and time efficiency of fueling and hotel stays understanding every minute counts to ensure DOT compliance and staying on schedule. Phone calls with Tohono O’odham Nation revealed additional requirements not indicated on state permits, the main one was a curfew that took place from 3:00pm until 6:00pm on SR86 and SR386. The pedestal was permitted for day time running only. Making it was crucial the final leg of the transport held a strict schedule. Maintaining a steady pace, performing the safety checks proficiently and taking the ½ hour required break, the load delivered before curfew.
The four Border Patrol Stations that were affected required a minimum of 1 weeks’ notice to coordinate barricade and guard shack removal / replacement. A concern was the impact the loads may cause on the security measures they perform. The Border Patrol was able to provide a sufficient parking location for both loads to be inspected and continue with their daily routine.
November 11, 2013 the Precision Heavy Haul transport team departed Tolleson, AZ for Socorro, NM. Encountering a slight delay due to heavy fog on a 150 mile construction detour near Roswell, NM, the unladen trailer still arrived at the VLA as scheduled on November 13th at 1:00pm. PHH’s assembly crew arrived on the 12th with the transport frames. The assembly of the pedestal transport frame was completed in a timely manner and the lifting fixtures bolted to the pedestal perfect. Due to strict tolerances the reflectors transport frame arrived in one piece on a PHH fabricated tilt frame. Transporting this frame at a 50.5 degree angle made the loaded dimension permit fees more cost effective. This frame was prepositioned on elephant stands and prepped to accept the reflector.
Upon arrival the perimeter frame trailer was spread to the desired width and the pedestals carrying frame was placed on the trailer in preparation for the following day’s load out. On November 14th a flawless load out took place and all antenna components matched to a perfect fit in both carrying frames. Not only did every element of the load out perform better than expected, but the pedestal weight came out 3,000# lighter than anticipated.
November 15th PHH arrived at the eleven axle staging area at 5:30am and conducted a pre-trip inspection on the equipment and load. New Mexico Highway Patrol arrived at 6:30 am; upon completion of their inspection PHH’s lead driver conducted a pre-roll meeting. Discussing safety concerns, responsibilities, placement, and the use of two way radios and CB’s ensured everyone involved was made clear on their duties. Personnel received detailed copies of the route, accompanied by a shortened turn by turn sheet which included the bridges that would need to be center lined at 5 mph. PHH rolled at 7:15am with an escort entourage consisting of three PHH pilot cars, one PHH service truck and four New Mexico Highway Patrol. The patrol cars were very efficient clearing traffic and eliminating any vehicles from stopping between any guard rails. The transport maintained steady speeds on the two lane roads arriving at the New Mexico/ Arizona state line in two and half days.
PHH’s approved southern route ran southeast from Socorro, along the New Mexico / Texas border, northwest in New Mexico entering South Eastern Arizona, back south near the Mexico border and finishing in Southern Arizona. PHH chose not to use a more direct route by staying on I-10 in Arizona. Portions of I-10 required night running due to hours of service, switching from days to nights and back to days, added two days. The utilized portion of I-10 consisted of numerous low overpasses forcing the load to ramp each of them. The majority of the off and on ramps required the trailer to be steered due to extremely tight radius and down to 1” clearances on guard rails, spotters walked the load providing two way radio guidance for the driver and tillerman.
In the instance where low over passes could not be ramped or excessive crowns occurred, PHH was able to utilize the transports dual hatboxes to gain 24” of ground clearance, or reduce it down to 1” of ground clearance. This feature proved to be extremely efficient for railroad crossings. Height adjustment was conducted during railroad clearance approval at every crossing. Arizona requirements were, four Highway Patrol and two escorts for the pedestal, delivering on schedule November 15th.
The main reflector was big in dimension but small on weight. PHH chose an eight line Goldhofer with gooseneck for its maneuverability and ability to maintain levelness for negotiating supers and overpass clearance. The trailer also provided the capability to clear most signs, fences and highway structures by raising or tilting the load. With the reflector, being smooth and non-magnetic, PHH’s only option to meet the DOT light spacing requirements for night time operations was to utilize rope lighting, tie wiring it around the entire top perimeter of the reflector, where the ground cable was attached. Numerous spot lights were also placed on the trailer deck to illuminate the sides and base to help the driver and spotters better see clearances.
The submitted reflector route traveled on freeways the majority of time, only using the business district in 3 cities, Socorro, Las Cruces and Tucson. The gross weight and axle group weights eliminated all bridge concerns except one in New Mexico. Six weeks before the reflector was scheduled to move, New Mexico denied one bridge on I-25 between Socorro and Las Cruces, the Nogal Canyon Bridge.
New Mexico suggested an alternate route to bypass the bridge that eventually intersected with the existing route on I-25. PHH’s survey crew was immediately dispatched to assess and measure the road. The road was negotiable for the chosen combination, consisting of 90 degree turns, 8% supers, numerous signs and trees. We just added additional signs and trees to the remove/ replace list. Permits were issued and the delivery schedule remained the same.
December 4th the first thought of a delays entered into mind, a winter storm front moved in and winds gusted to eighty miles per hour. With the reflector previously being prepositioned on elephant stands, the transport crew was able to self load and secure the reflector in a safe manner despite the harsh conditions. New Mexico required transport operations to commence on weekend nights because of traffic congestion and law enforcement requirements. The Friday night move allowed transport crew to reset log books and wait out the snow storm.
The evening of December 6th brought clear skies and the load remained on schedule departing the VLA. The same pilot and law enforcement requirements were in effect as the pedestal load. An additional concern was the possibility of crowds gathering due to the fact the load would look like a UFO traveling at night through an area of the country famous for extraterrestrial sitings.
Personnel utilized a detailed route survey which included the degree of slope the roads held at each obstacle where the trailer would need to be leveled. PHH’s engineering department provided a scale showing the increments of increased height while in a side slope. At forty feet wide, the load height changed 7 ½ inches for every 4 inches of lean at the deck.
Having this vital information allowed Precision to prepare for any clearance issues well in advance. The widest load every to cross New Mexico and Arizona arrived to the base of Kitt Peak on December 10th, two days earlier than scheduled, keeping trans-loading on schedule.
PHH’s chosen transport for the pedestal was an eight line Goldhofer for the mountain transport segment of the project. This provided a long enough deck to accommodate the pedestal in the transport frame. The hindrance of the cabin section that projected down 18 inches was solved by utilizing 2 foot elephant stands under the support frames of the transport frame. This allowed ample clearance for the cabin and gained ground clearance for the width.
PHH accepted the fact that adding height to the load would raise the center of gravity increasing the tipping factor. The trailer was set into a four point configuration increasing the stability triangle to a comfortable range. The 22’8” wide load would need to navigate the mountain road averaging twenty four feet wide for the first 10.5 miles with a 6% to 8% grade and up to an 8% lateral slope. The final half mile of access road began with the need to negotiate a 45 degree switch back for a left turn, onto a 15’ wide road with a 12 % grade. Washed out shoulders and numerous rock outcrops lined the access road on each side.
PHH eliminated this impossible turn by utilizing the Goldhofer’s ability to reverse direction. Having a second prime mover staged on the access road, PHH passed the turn, switched ends with the loader, attached the second prime mover to the rear of the trailer, now making it the front the pedestal delivered to the observatory on November 21st.
The chosen transport for the reflector was a six line Goldhofer with a fabricated tilt frame that would suspend the load at a 60 degree angle. During the months of preplanning, PHH requested gathered data that the observatory collected over numerous years of monitoring wind speeds. Records showed December to have moderate wind speeds with gust of 60 + mph in the early to late afternoon time frames.
Modifications were also needed to achieve the center of gravity of the load with the trailer. PHH opted to utilize 26,136 lbs of counterweight centered on the deck of the trailer and offset an additional 25,665 lbs, to carry the entire loads CG 1/16 of an inch offset and 84” above ground level with 48” trailer deck height. Understanding the road conditions, trailer capabilities, and stability triangle, the trailer was configured into four point suspension. Adding the counter weight to lower and midpoint the center of gravity, decreased the tipping factor from an original wind load safety factor of 2-1 against a 35 mph wind to 3-1with a 63mph wind.
The build team spent December 11th building the tilt frame onto the Goldhofer and placing counterweight at the predetermined location. Push bars were attached, and the trailers hydraulic functions were checked. Lifting extension were inserted and pinned in the respective locations of the frame. The following days Trans-loading of the reflector was completed in a timely manner and once again all components matched to a perfect fit. The dual acting hydraulic cylinders were attached making the process of releasing the cranes and removing the lifting extensions seamless.
Loaded dimensions were two feet wider than the pedestal load measuring 24’9”, but had an offset of nearly 13 feet. Kitt Peak is on reservation land; natural obstructions were allowed to be trimmed but not removed, making the outline measurements of the load critical to ensure a round peg could fit in a square hole.
The additional challenges that the offset created, mainly took place on the access road segment of the route. SR386 allowed the trailer to hold the guard rail leaving the offset portion to clear width restrictions. Orientation was significant, knowing the load was needed to be reversed for the access road like the pedestal. The high side of the load measuring 35’9” high, needed to travel opposite of the side hill cut creating more obstacles for the first 10.5 miles but eliminating the need for removing power lines near the observatory. PHH requested and received an outage for the power, adding clearance comfort with the power lines. The transport was able to evade the eves on the observatory while maintaining clearance from power lines with the reflector setting at a 60 degree angle.
To ensure clearance over the irremovable rock outcroppings on the passenger side of the load holding the 13’ wide offset, driver side wheel sets were forced to travel where the road did not exist. With the counterweighted trailers ability to roll side to side, PHH gained an additional tool, having the ability to gain over 1 foot of additional ground clearance while staying within the stability triangle.
Previous and existing weather conditions washing out all material from the first move, modifications to the access road and widening did not take place until the reflector arrived at the base of Kitt Peak. The road was required to be widened approximately 15’, and extend both in length and width due to the extreme grade and side slope. PHH provided and set 8 x16 x 1 1/8 trench plate in line with the tire path of trailer, providing additional support and disperse ground pressure.
The reflector was scheduled and coordinated for a 7:30 am roll on December 13th. The transport team was correct in believing this would allow the transport ample time to clear the most critical canyon areas where the gusts proved to be most predominate. The entire road was closed at 8:00am by the Tohono O’odham law enforcement after observatory traffic traveled up the mountain. Responsibilities were assigned during the pre-roll meeting including constant radio contact with a dedicated wind monitor. Safety precautions were put in place to stabilize the loaded trailer if winds became a concern and Precision Heavy Haul once again successfully negotiated the 45 degree turn and delivered the reflector to the observatory at 4:00pm.
Thanks to months of planning, state of the art equipment, and the skills of everyone involved, the work was completed within budget, on or ahead of schedule with no incidents or accidents. The 12 Meter Radio Antenna located at its new home at the ARO “Arizona Radio Observatory” is scheduled to be fully operational by the fall of 2014.
PROJECT MAN HOURS
Engineering – 936 man hours
Survey and/ Planning – 774 man hours
Fabrication – 1701.5 man hours
Set up – 640 man hours
Transport Operation – 1865.75 man hours
(6) Kenworth T-800’s
(1) PHH Dual lane hydraulic spread perimeter frame 11 axle with Nelson Goosenecks
(1) XL Specialized single drop
(1) Siebert 16 tire
(1) 980 wheel loader
(1) Goldhofer THP/ SL (3 +3)
(1) Goldhofer THP/ SL (4 +4)
VLA Socorro, NM to Kitt Peak, AZ
Pedestal and cabin on dual lane hydraulic spread 11 axle perimeter frame with push truck
Net weight – 143,000 lbs
Gross weight – 472,750 lbs.
Length – 185’4”
Width – 22’8”
Height – 16’6”
Main Reflector on 8 line Goldhofer
Net weight – 15,000 lbs
Gross weight – 154,000 lbs.
Length – 72’0”
Width – 40’0”
Height – 15’8”
Kitt Peak staging area to 12 meter observatory site
Pedestal on 8 line Goldhofer
Net weight – 143,000 lbs
Gross weight – 398,000 lbs.
Length – 120’0”
Width – 22’8”
Height – 20’0”
Main Reflector on 6 line Goldhofer
Net weight – 15,000 lbs
Gross weight – 246,000 lbs.
Length – 110’0”
Width – 24’9”
Height – 35’9”
This project would not have been successful without the dedication and hard work of the Precision Heavy Haul TEAM. Thank you Greg Jordan, P.E. and all the personal at the fabrication shop at Kalyn Siebert which provided an excellent timely efficient service during the fabrication of some of the fixtures used in this project. Lastly, special thanks go to the officers of New Mexico DPS, Arizona DPS and the Tohono O’odham Nation Law enforcement for providing a safe environment for both the cargo as well as all individuals during the transport.