Bridge Inspection Access to Minimize Operational Impacts

Transcription

1 Bridge Inspection Access to Minimize Operational Impacts Word Count: 3,567 Corresponding Author: Jeremy Koonce, PE, SE Collins Engineers, Inc. 123 N. Wacker Dr., Suite 300 Chicago, IL Phone: Fax: Co-Author: Todd Demski, PE, CWI Collins Engineers, Inc. 123 N. Wacker Dr., Suite 300 Chicago, IL Phone: Co-Author: Mike Rowe, PE Metra 547 W. Jackson Blvd. Chicago, IL Phone: Co-Author: Nate Morriss, PE, SE Metra 547 W. Jackson Blvd. Chicago, IL Phone: AREMA

2 Abstract Minimizing delays on today s railroads is always a top priority especially in urban areas. Trains can come to a standstill, literally, when bridge inspections take up valuable track time. Typically, these daytime inspections are limited to shortened windows of time or intermittent times staggered throughout the day to accommodate the inspection work. Generally, if full days cannot be worked then the duration of the inspection will be dragged out as well as increase the overall costs. Night work in urban areas is an option but poses new challenges. Night work can be more dangerous and is usually slower and more costly than working during daytime hours. In addition, it can be very difficult to adequately inspect a bridge in the dark even with supplemental lighting. This paper discusses the experience of the authors on a project which successfully eliminated the need to considerably foul the tracks during an in-depth inspection of a steel truss structure. The inspection work took place in the southern metropolitan area of Chicago for Metra, Chicago s suburban commuter rail service. A variety of access methods were utilized including technical climbing with rope access, traditional structure climbing incorporating a harness and lanyards, and finally a boat-mounted lift. The authors detail each method of inspection used, why it was chosen, and how it succeeded in allowing the timely completion of the work without significant impacts to railroad operations. The authors suggest how this type of planning and creativeness for inspections can be used nationwide to greatly reduce the need to foul tracks during these required and important bridge inspections AREMA

3 Bridge Inspection Access to Minimize Operational Impacts When performing bridge inspections, minimizing delays on today s railroads is always a top priority especially in urban areas. Trains can come to a standstill, literally, when bridge inspections take up valuable track time. Typically, these daytime inspections are limited to shortened windows of time or intermittent intervals staggered throughout the day to accommodate the inspection work. Generally, if full days cannot be worked then the duration of the inspection will be dragged out as well as increase the overall costs. Night work is an option but poses new and different challenges. Night work can be more dangerous and is usually slower and more expensive than working during daytime hours. In addition, it can be very difficult to adequately inspect a bridge in the dark even with supplemental lighting. The authors utilized an innovative approach to complete a detailed bridge inspection which encompassed a variety of different types of access in order to minimize track disruption during the inspection process. The bridge inspection was performed for Metra, the commuter rail division of the Regional Transportation Authority of Northeastern Illinois (RTA). The RTA is the commuter transportation system for northeastern Illinois which includes Chicago and its surrounding suburbs that consists of over 8 million people. Metra operates eleven lines, five lines maintained by Metra and six lines contracted with the Burlington Northern Santa Fe, Union Pacific, and Canadian National. These train lines serve Chicago and branch out to reach the vast outlying metropolitan area. The bridge inspected as the focus of this paper is located on the Metra Electric District (MED). The MED, as the name suggests, is an electrified rail line. This is the only electrified line on Metra s system. The train is powered by overhead catenary lines that carry 1,500 volts direct current (DC). As of 2010, the MED consisted of 40.6 route miles operating 170 trains with an average weekday ridership of over 36,000. The MED serves Millennium Park Station in downtown Chicago and branches out to serve three different areas to the south: Blue Island, University Park, and 93 rd Street (South Chicago). The bridge inspected was Bridge No over the Little Calumet River on the MED in Riverdale, Illinois and is located between the Kensington and Riverdale Metra stations AREMA

4 The inspection for Metra was completed in two days during the summer of The primary purpose of the inspection was to determine the condition of the structure components located above water. This detailed inspection required the inspectors to get within an arms reach of the fracture critical members. The underwater components of the bridge were inspected in February 2009 as a part of the same task order agreement. Photograph 1. Overall View of Bridge Bridge No consists of five spans with an overall bridge length of approximately 591 feet from back to back of each abutment. The bridge carries two tracks. The superstructure and substructure configuration is different for each track. All spans are simply-supported on reinforced concrete piers and two reinforced concrete abutments. The bridge is situated in a north-south direction and the Little Calumet River flows beneath the structure from east to west. At the time of inspection there was approximately 30 feet of freeboard between the bottom chord of the truss span and the waterline. Refer to Photograph 1 for an overall view of the bridge AREMA

5 The main truss span, Span B, carries both tracks and consists of a Warren through truss type superstructure. The truss has an overall span length of 310 feet, 5 inches from center to center of the bearings, and a maximum height of 62 feet at the truss midspan. The construction of the truss members and secondary members generally consists of riveted and bolted built-up members. There are a total of 11 floorbeams and the tracks above are carried by four longitudinal stringers, which are simply supported between each floorbeam. The approach spans consist of a combination of built-up steel deck girders and rolled wide flange members. There were three primary types of access methods utilized to complete this inspection: rope access, boatmounted lift, and traditional structure climbing. There were also conventional methods employed such as ladder access and a 14 foot boat and motor to complete the inspection, but these common methods are not discussed herein. Several factors were considered to determine the best access method for this inspection. First, Metra preferred a limited time window for the inspection. The tracks were only permitted to be fouled during the hours of 9 am to 3 pm. The primary reason was high train volume to and from Chicago during the peak workday commuting times. Furthermore, weekend work was not desirable due to the high volume of tourist traffic. In addition to the timeframe constraints that needed to be taken into consideration, the overhead catenary power lines were to remain energized and posed a significant safety hazard. One option considered for the inspection of the truss sections was a rail-mounted lift vehicle. While a viable option, the limited amount of time that the tracks could be fouled made this undesirable. If a rail-mounted lift vehicle were to be used, the inspection would require a significant window of time to foul the tracks. Furthermore, the overhead catenary power lines would have needed to be de-energized prior to the start of the inspection, and reenergized after the inspection was completed. The only reasonable window of time this could have taken place would have been during nighttime hours. The second option considered was the use of rope access. This option was a self-contained and portable option. Since rope access could be controlled and isolated away from the catenary power lines, as well as away from railroad traffic, the inspection could take place without de-energizing the power lines and without significantly fouling the tracks. Furthermore, utilizing rope access would eliminate a portion of the manpower required by Metra for the de-energizing and re-energizing of the catenary power lines, as well as provide Metra with cost savings on the rental of a rail-mounted lift vehicle. Flagmen were still required and some limited 2011 AREMA

6 fouling of the track would occur, but in the end rope access was determined to be the most efficient method to inspect the truss portions of the bridge above the tracks. A similar evaluation was performed to determine an efficient method for inspecting the remaining portions of the bridge including the truss superstructure below the tracks, the approach spans, and substructure units. One option considered was to use a rail mounted under bridge inspection vehicle, but once again, with the restricted work times coupled with the cost of equipment this was not a desirable approach. Another option was to use a barge with a lift vehicle. While this would provide access to some of the underside of the superstructure, the barge can only be used where it can fit and is not readily moved without a costly tug and crew continually on-site. Once again it was decided to look into other options. A combination of two methods was determined to provide an efficient inspection based on cost and timeliness. This combination involved using a boat-mounted lift and traditional structure climbing. The boat-mounted lift would allow access to the lower portions of the trusses and to several other locations on the superstructure as well as the substructure units situated in the water. Traditional structure climbing utilizing a harness and double lanyard system would provide a means of access to the girder approach spans where the boat-mounted lift could not reach. Using this combination of techniques a complete inspection could be performed. The inspection work adhered to current applicable FRA regulations, the AREMA Bridge Inspection Handbook, and to Metra s requirements. Prior to going out into the field the appropriate safety measures were performed and personnel protective equipment (PPE) was obtained and inventoried. Safety measures included completing the required Metra Contractor On-Track Safety Orientation which is located through the website PPE for this project included hard hats, safety glasses, reflective safety vests, steel toe boots, life jackets, gloves, and fall protection. Other items gathered and prepared which were essential to safety on this project, but may not be included as PPE, were Metra flagmen with lookout kits, a marine radio, and safety and rescue plans. In addition, all inspection equipment used by any inspector climbing either by rope access or traditional structure climbing was tethered to eliminate the potential of dropping equipment onto the tracks, into the water, or, most importantly, on any person below AREMA

7 Rope access is a technique used by inspectors to gain access to a structure using ropes as the primary means of support, positioning, and safety protection. Rope access inspectors utilize a two-rope system. One rope is used as the working (primary) rope, while the second rope is the safety (back-up) rope to protect the inspector in case of a fall. Utilizing a two-rope system essentially means the inspector is 200 percent tied-off at all times while supported by rope. While performing rope access inspections, inspectors are governed by the Society of Professional Rope Access Technicians (SPRAT) and the Safe Practices for Rope Access Work. Even though rope access inspectors are governed by the SPRAT guidelines, FRA guidelines are adhered to when applicable and for areas that may not be covered under the SPRAT guidelines. During the inspection of this bridge, the rope access team consisted of two Level I Technicians (engineer inspectors), one Level II Lead Technician (rigging, site safety), and one Level III Rope Access Supervisor (rigging, site safety, site supervision). Refer to Photograph 2 for a view of rope access being performed. Photograph 2. Typical View of Rope Access Being Performed AREMA

8 Prior to commencing the inspection work, a Job Safety Hazard Analysis (JSA) was performed by the Level III Rope Access Supervisor. This document is used to identify potential hazards within the access and hazard zones of the rope access work area. Since the bridge is a through truss serving a railroad with overhead catenary lines, the access and hazard zones were identified to be within 25 feet of the Metra tracks. Three major hazards were identified during the review of the JSA. The first major hazard was an overhead electrical line located approximately 10 feet above the bridge deck that was mounted to the east truss of the bridge. The second hazard was the 1,500 volt catenary power lines for the train, which is located approximately 25 feet above the bridge deck centered in the truss. The last major hazard was the train traffic on the MED. The trains were required to slow down in the work area; however to maintain Metra s train schedule, the trains were not required to stop. Coordination between all participating parties was crucial to the successful completion of this project. The first major hazard was identified and discussed with a Metra electrical crew. The crew identified the electrical line and isolated the source of the power. They were then able to perform a lock-out/tag-out procedure for this hazard. Since the catenary power lines were not able to be de-energized, the rope access inspectors were to stay a minimum of 10 feet away from the wires at all times per industry standard for power lines carrying 1,500 volts. In order to provide the rope access inspectors the greatest amount of clearance, all ropes were rigged on the outside of the truss fascia. The inspectors were then able to rotate themselves around the truss members to get within an arms reach of the fracture critical and non-fracture critical truss members and connections. This also helped in avoiding the third major hazard as the ropes needed to be removed from the interior of the through truss prior to trains passing. There were Metra supplied flagmen on the bridge who signaled to the climbers when a train was approaching. This gave the climbers enough time to clear ropes to the exterior fascia of the truss, which could pose an entanglement hazard, and to climb to the outside of the truss and position themselves in a stop position. The flagmen used an air horn for signaling approaching trains and to signal when the train had cleared and work could resume. Refer to Photograph 3 for a view representing how the coordination effort allowed for the safe passage of a train through the inspection area AREMA

9 Photograph 3. View of a Train Passing through Inspection Area. In addition to identifying the hazards that may be encountered, a detailed rescue plan needed to be documented in the JSA. Since the inspection utilized a boat-mounted lift to perform the work on the underside of the bridge deck, the rope access inspection supervisor identified this as the most efficient and practical option for rescue. In the event of an emergency, the Level II and Level III Technicians would assist in the rescue and lower the individual to the waiting boat. As previously mentioned, Metra allowed for a 9 am to 3 pm window where the tracks could be fouled. At 8am, the inspection crew met with Metra to perform a daily safety briefing, as well as a daily JSA briefing. At 9 am, the inspection crew was able to enter the work site. The rope access rigging took approximately thirty minutes. By 2011 AREMA

10 9:30 am, rope access inspection activities were commencing. The inspection was performed between 9:30 am and 2:30 pm when all rope access activities were stopped so that the rigging could be removed from the bridge by 3 pm. At 3 pm the tracks were cleared of all equipment and personnel and normal train operations resumed. Once work had commenced at 9 am, rope access rigging technicians used traditional structure climbing procedures to climb the diagonals utilizing slings through oval openings staggered along the diagonal. The rigging technicians then worked from the top chord to perform the rope rigging for the rope access inspection engineers. Ropes were set at each panel point for inspection purposes. The inspectors were able to climb the ropes to inspect each of the vertical members, while using rope-to-rope transfers to inspect the diagonal members of the bridge. At the top chord connection with a vertical and/or diagonal panel point connection, the inspector was able to rotate around the vertical member in order to get within an arms reach of the connection. Since rope access was not a viable option for the underdeck portion of the inspection, the rope access inspectors only inspected the portions above the tracks. The lower portions of the main truss span, as well as portions of the approach girders and superstructure components over the water, were accessed with a boat-mounted lift. A boat-mounted lift was leased from an access equipment company with a driver and operator. It provided a unique capability to access the underside portions of this relatively low freeboard structure. The freeboard at the time of inspection was approximately 30 feet but the boat-mounted lift could reach heights of over 60 feet. The pontoon outriggers allow the bucket to be safely manipulated into nearly any position. There are motors on the bow and stern of the boat so that once the operator positions the boat under a girder, floorbeam, or stringer then the operator can steadily move the boat along these members providing an inspection within arms reach of them. This provides an efficient method to visually inspect these otherwise difficult to access areas of the bridge. Refer to Photograph 4 for a view of the boat-mounted lift during inspection AREMA

11 Photograph 4. View of the Boat-mounted lift during Inspection. The boat-mounted lift was launched from the Calumet Boating Center which is located approximately two miles west of the structure. The location of the bridge on the Little Calumet River is near the start of the Cal-Sag channel, which essentially links Lake Michigan to the Mississippi River, and is extremely busy with barge traffic and recreational boats. Coordination between Collins and the U.S. Coast Guard was essential to safety on the project. A notice to mariners was issued for the duration of the inspection work and a marine radio was kept on the boat and continuously monitored. The features of the Little Calumet River are ideal for the boat-mounted lift s capabilities. The river is broad and the flow of the river is typically slow and smooth with the exception of passing boat traffic in this no wake area. This inspection was performed while trains were operating above and did not require fouling the tracks. There were some locations where the boat-mounted lift could not reach because of the limitations of the terrain or limitations of the basket size to maneuver in between the girders on the approach spans. For these situations traditional structure climbing was performed AREMA

12 Traditional structure climbing refers to climbing with standard fall protection such as a harness and double lanyard system. This type of climbing keeps the inspector 100 percent tied-off to the structure. The inspector would start climbing operations from either the abutment or would use the basket on the boat-mounted lift as a means to enter the structure. The portions of the structure that were inspected using this type of access were the inside portions of the two girder approach spans. Using the regularly spaced lateral braces as tie-off points allowed for an efficient and safe inspection. Due to the large lateral bracing member sizes, special consideration had to be taken into account on how the inspector attached the harness lanyards to the members. The inspector determined the most efficient method would be to use specially designed lanyards, which allow for wrapping the member and clipping back to the lanyard webbing. These types of lanyards meet the FRA requirements for gate strength and side loading in the event of a fall. This eliminated the need for extra slings and tie-off points to be used. Similar to the inspection using the boat-mounted lift, this inspection was performed while trains were operating above and did not require fouling the tracks. Refer to Photograph 5 for a typical view of the superstructure inspected by traditional structure climbing techniques. Photograph 5. Typical View of the Interior of the Girder Approach Spans AREMA

13 A safe, efficient, and cost effective inspection of Metra Bridge 16.9 was the goal of this project. By combining these three methods of access for the inspection it allowed for daytime inspection work and reduced the total on-site inspection time as compared to using typical rail mounted vehicles and a barge with a man lift. Using the boat-mounted lift as a means of inspection and a potential rescue vehicle for the rope access and traditional structure climbing techniques was an efficient use of this type of equipment. Specialized access equipment such as rail mounted vehicles, barges, boat-mounted lifts, etc, is generally very costly to lease, so time saved in the field generally indicates a cost savings for the project and to the client. In addition to the potential cost savings, this inspection was performed without any operational down time for the railroad and without significantly fouling the tracks. These types of innovative inspection practices can be implemented nationwide on many structures on the nation s railroad lines to significantly reduce the operational down time for a railroad and the need to foul the tracks. Down time can disrupt operations and result in increased costs for the railroad companies by way of lost time, penalties, fees, fines, etc. Bridge inspections have been and will continue to be a high priority for railroad owners to ensure safe train traffic and to meet FRA regulations. Railroad owners do not need to settle for the standard inspection methods based on the philosophy of That s how it s always been done. When performing these necessary and required inspections sometimes it is important to step back and think outside of the box and consider new alternatives in addition to standard means of access AREMA

14 Jeremy Koonce, PE, SE Project Manager Todd Demski, PE, CWI Project Manager

15 Hands-On Bridge Inspection Must Minimize Impact to Train Traffic

16 Commuter rail division of the RTA Operates 11 lines serving Chicago from the outlying suburbs 5 lines owned by Metra and 6 lines contracted with other railroads

17 Only electric line on Metra system Powered by 1,500 volts through overhead catenary lines 40.6 miles of track to serve south Chicago metro area

18 Located in south Chicago metro area Connects Lake Michigan to the Cal- Sag Channel Serves barge traffic and heavy industry

19 5 Spans, 591 total length Bridge carries two tracks Main span is Warren Through Truss Truss span 310 long and 62 high Approx. 30 of freeboard to water below Approach spans are combination of deck girders and multiple rolled beams

20 Overall View of Bridge

21 View of Main Truss Span

22 View of Deck Girder Approach Span

23 View of Approach Spans

24 Overhead catenary power lines Adjacent overhead electric lines Train traffic Barge traffic Working from heights

25 Safety Limited work times Tracks must remain open to traffic Work to be performed during the daylight hours Coordination with all parties

26 1. Rail-Mounted Lift Vehicle 2. Rail-Mounted Under Bridge Inspection Vehicle 3. Barge with Lift Vehicle 4. Rope Access 5. Traditional Structure Climbing 6. Boat-Mounted Lift Vehicle

27 1. Rail-Mounted Lift Vehicle 2. Rail-Mounted Under Bridge Inspection Vehicle 3. Barge with Lift Vehicle 4. Rope Access 5. Traditional Structure Climbing 6. Boat-Mounted Lift Vehicle

28 Provides safe access to portions of main truss span above the tracks Allows for hands on inspection Tracks below can remain open Time and cost effective

29 Provides safe access to the portions of the main truss span below the deck and outside faces of the approach span deck girders Allows for hands on inspection Tracks above can remain open Time and cost effective

30 Provides safe access to inside portions of deck girder approach spans allows for hands on inspection Tracks above can remain open Time and cost effective

31 Inspection adhered to FRA and AREMA Guidelines All personnel in the field completed Metra s Contractor On-Track Safety Orientation Work and Rescue Plan developed before inspection work began JSA completed daily in the field

32 Personnel protective equipment for all inspectors Metra flagman on site daily with lookout kits U.S. Coast Guard notified and marine radios monitored

33 Governing Bodies SPRAT and IRATA Governed by SPRAT and the Safe Practices Guidelines Inspectors utilize a two rope system for inspection 3 levels of certification

34 Structure climb to reach top chord Rigging from top chord Ropes not to impede train or boat traffic Various techniques to access all potions of truss Rigging performed on outside fascia

35 Quickly deployed from nearby launch Ideal water conditions Adequate freeboard clearance Same PPE required as standard lift Steady and mobile

36 Climbing Equipment Consists of Harness and Double Lanyard System Inspector is 100% Tied Off Lanyard Gates Designed to Clip Back to Lanyards Inspector Able to Tie Off to Lateral Bracing between Deck Girders

37 The goal of this project was a safe, efficient, and cost effective bridge inspection This innovative approach utilizing three access methods satisfied the above criteria while not sacrificing valuable track time

38 When performing these necessary and required bridge inspections, sometimes we need to leave the mentality: That s how it has always been done.

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