A structural failure caused the bridge to fall ~100 feet, collapsing onto 6 vehicles in the park below and injuring 4 people. It is another unfortunate reminder of the importance of reliability and maintenance in infrastructure.
NTSB Chair Jennifer Homendy reminds us, “The Fern Hollow bridge catastrophe must serve as a wake-up call that we cannot take our infrastructure for granted. Only through diligent attention to inspection, maintenance, and repair can we ensure the roads, bridges, and tunnels we all traverse every day are safe for the traveling public. Lives depend on it.”
This week’s newsletter will cover the NTSB’s description of the failure, differentiate between failures and breakdowns, and provide quick tips on bridge maintenance.
Image Courtesy NTSB
Failure of Bridge Maintenance
Here is NTSB’s breakdown of the incident:
NTSB investigators determined that the collapse started with a failure of the transverse tie plate on the southwest bridge leg.
The failure was caused by extensive corrosion and section loss.
The corrosion and section loss were the result of continual accumulation of water and debris, preventing the formation of a patina.
Repeated maintenance and repair recommendations were documented in many inspection reports, but the City of Pittsburgh did not act on them.
The lack of action led to the deterioration of the fracture-critical transverse tie plates and the structural failure of the bridge.
Along with inaction by the city on inspection recommendations, NTSB investigators discovered that PennDOT contractors working on behalf of city conducted inspections that…
were not compliant to guidance
did not identify fracture-critical areas on the bridge’s legs
did not accurately calculate load ratings
NTSB investigators determined that three main aspects of the load rating calculation were not accurate:
How holes and section loss on portions of the bridge legs were handled
The effective length factor used to estimate bridge legs’ ability to resist buckling
The amount of asphalt wearing surface on the bridge at the time of the collapse
If the load rating calculation had taken these factors into consideration, they would have found that the bridge needed to be closed.
Due to this oversight at the city, state, and federal level, the NTSB has chosen to issue 11 new recommendations to the Federal Highway Administration, PennDOT, the City of Pittsburgh, and the American Association of State Highway and Transportation.
What is a failure? According to IDCON INC, a failure is when the equipment condition reaches an unacceptable level. This can include high temperature or vibration levels, too little flow, etc. If the equipment is left to operate, the failure will develop into a breakdown.
The breakdown is the point where the equipment stops functioning, which can lead to safety incidents, lost production, unplanned shutdowns, and incur cost.
The time between a failure converting to a breakdown is called the Failure Development Period.
Image Courtesy IDCON INC
As you can see in the image, the Inspection phase of the Failure Developing Period is critical to stopping the breakdown from occurring. In the case of the Fern Hollow Bridge collapse, inspections were performed and reported by the city, but not acted on, and some inspections were done incorrectly by PennDOT contractors. The failures (extensive corrosion and section loss) found in the city’s inspections were reported but not repaired, and the load rating calculation by PennDOT was incorrect (leading to further wear), so the problems developed to the point that the bridge collapsed.
Bridge Maintenance Tips
A well-developed bridge maintenance program is essential for public safety and the safety of reliability engineers and maintenance techs working on them. Bridge failures are not only dangerous but can be very costly. Waagner Biro Bridge Services has put together a list of basic bridge maintenance tips to be aware of when handling bridges.3
Why is bridge maintenance essential?
Safety assurance
Economic benefits and longevity
Preventive care
Keeping the trust of the public
Environmental considerations
According to Waagner Biro, creating a bridge maintenance schedule that encompasses the specific needs of the structure is important for engineers and technicians to keep on track. The frequency of bridge maintenance will vary depending on the age of the bridge, the material it was built from and what environment it is exposed to, and the design. Best practice is to perform a thorough inspection once every 2 years, but conditions/heavy traffic may necessitate more frequent inspections.
5 Key Bridge Maintenance Tips:
Regular Inspections: Thoroughly inspect all parts of the bridge, including structural components, surface, and foundation. Wear, corrosion, or signs of other damage must be included in the inspection report and addressed as soon as possible.
Timely Repairs: Immediately addressing failures found in inspections is crucial to bridge maintenance, as we see in the Fern Hollow Bridge incident. Delayed repairs can lead to deterioration and increase the risk of an unsafe breakdown.
Cleaning and Debris Removal: Regular cleaning and debris removal is a vital task that is often overlooked in bridge maintenance. Leaves, dirt, and trash can accumulate, leading to drainage problems and corrosion.
Corrosion Protection: Another aspect of bridge maintenance we were reminded of by Fern Hollow. Corrosion protection includes application of protective coatings, ensuring proper drainage to avoid water accumulation, and using corrosion-resistant materials when designing, constructing, and repairing bridges.
Load Management: Load management for bridges includes monitoring the weight and type of vehicles that are permitted to use the bridge, ensuring they are within the load capacity (which much be calculated correctly). Overloading causes undue stress on the bridge which can lead to damage and reduce the lifespan.3
The Fern Hollow Bridge collapse underscores the critical importance of diligent bridge maintenance and oversight. The incident, caused by extensive corrosion and section loss that went unaddressed despite repeated recommendations, serves as a stark reminder of the potential consequences of neglecting infrastructure maintenance.
The breakdown highlights the need for accurate inspections, timely repairs, and load rating calculations to prevent such catastrophic events. Implementing a comprehensive bridge maintenance program, including cleaning, corrosion protection, and load management, is essential for ensuring public safety, worker safety, and the longevity of infrastructure.
With literally thousands of dangerous materials being used/transported/discarded every day, the process of choosing protective clothing has become increasingly complex for today's safety and hygiene professional. It is important to understand the distinction between three broad types of protective garments used today. Generally classified as disposable, reusable, and limited-use garments, these three general categories provide a basic framework for clothing decisions.
With literally thousands of dangerous materials being used/transported/discarded every day, the process of choosing protective clothing has become increasingly complex for today's safety and hygiene professional. It is important to understand the distinction between three broad types of protective garments used today. Generally classified as disposable, reusable, and limited-use garments, these three general categories provide a basic framework for clothing decisions.
With today's limited internal resources, it's tough to transform machine maintenance from reactionary to preventive, and ultimately proactive, despite the obvious upsides in higher overall equipment efficiency (OEE), better process control and lower total cost. Outsourcing this requirement to a third-party specialist, however, is a cost-effective alternative, according to companies that have crunched the numbers.
With today's limited internal resources, it's tough to transform machine maintenance from reactionary to preventive, and ultimately proactive, despite the obvious upsides in higher overall equipment efficiency (OEE), better process control and lower total cost. Outsourcing this requirement to a third-party specialist, however, is a cost-effective alternative, according to companies that have crunched the numbers.
There are many paradigms and legends surrounding maintenance management in plants. Often, the legends are known to be untrue, but people live with them because it is politically correct, or simply convenient. To be successful in improving equipment reliability and maintenance management, plants must break the legends that exist in their organizations. Some of the legends will be addressed in this article. You may find that these legends are uncomfortably close to describing how your plant operates.
There are many paradigms and legends surrounding maintenance management in plants. Often, the legends are known to be untrue, but people live with them because it is politically correct, or simply convenient. To be successful in improving equipment reliability and maintenance management, plants must break the legends that exist in their organizations. Some of the legends will be addressed in this article. You may find that these legends are uncomfortably close to describing how your plant operates.
Maintenance practices and technologies have evolved to meet the needs of the changing industrial environment. The function has evolved from a community of reactive fixers, to dedicated craftsmen, to proactive professionals. The next generation of personnel could well be based on practitioners of Quality Management Systems (QMS).
Maintenance practices and technologies have evolved to meet the needs of the changing industrial environment. The function has evolved from a community of reactive fixers, to dedicated craftsmen, to proactive professionals. The next generation of personnel could well be based on practitioners of Quality Management Systems (QMS).
Whether your company is large or small, whether you're hiring an entry-level employee or a top executive, any one of the following mistakes can result in a hiring disaster for your organization. Recent Kennedy Information audio conference speaker Lori Davila and her co-author Louise Kursmark offer 10 key points for reviewing your organization's hiring procedures and making adjustments where needed.
Whether your company is large or small, whether you're hiring an entry-level employee or a top executive, any one of the following mistakes can result in a hiring disaster for your organization. Recent Kennedy Information audio conference speaker Lori Davila and her co-author Louise Kursmark offer 10 key points for reviewing your organization's hiring procedures and making adjustments where needed.
Good Computerized Maintenance Management Software (CMMS) that schedules preventive maintenance work orders on your equipment is an integral component of any efficient maintenance department. Preventive and scheduled maintenance, efficiently scheduled, will not only reduce your maintenance costs, but will minimize emergency repairs and downtime, resulting in an increase in overall profitability.
Good Computerized Maintenance Management Software (CMMS) that schedules preventive maintenance work orders on your equipment is an integral component of any efficient maintenance department. Preventive and scheduled maintenance, efficiently scheduled, will not only reduce your maintenance costs, but will minimize emergency repairs and downtime, resulting in an increase in overall profitability.
To manufacture products on such a large scale means stocking a lot of equipment to maintain the operation. Fort Saskatchewan plant in Alberta, Canada, Roy Lura, process leader, estimated an inventory of more than 15,000 pieces of equipment. Until recently, however, there was no way to adequately track the items. With the help of a barcode-driven tracking system, this has changed.
To manufacture products on such a large scale means stocking a lot of equipment to maintain the operation. Fort Saskatchewan plant in Alberta, Canada, Roy Lura, process leader, estimated an inventory of more than 15,000 pieces of equipment. Until recently, however, there was no way to adequately track the items. With the help of a barcode-driven tracking system, this has changed.
Why us, why now? In years past, the engineer, manager or superintendent was responsible for improvement ideas. Maintenance people were "hands" hired to do what they were told. Today, organizations are lean and mean; we need the capabilities of all maintainers. The downsizing craze, however, has left everyone in a managerial role with too many tasks and too little time. There's no one left to cut costs!
Why us, why now? In years past, the engineer, manager or superintendent was responsible for improvement ideas. Maintenance people were "hands" hired to do what they were told. Today, organizations are lean and mean; we need the capabilities of all maintainers. The downsizing craze, however, has left everyone in a managerial role with too many tasks and too little time. There's no one left to cut costs!
In this paper we are concerned with design and innovation in the context of long-term service driven engineering projects. The cases reveal a number of ways in which new organisational arrangements have emerged from attempts to deal with these difficulties and also some of the mechanisms that have helped companies to identify the design implications of future maintenance requirements.
In this paper we are concerned with design and innovation in the context of long-term service driven engineering projects. The cases reveal a number of ways in which new organisational arrangements have emerged from attempts to deal with these difficulties and also some of the mechanisms that have helped companies to identify the design implications of future maintenance requirements.
I was asked recently to give a second opinion on the cause of failure of an axial piston pump. The hydraulic pump had failed after a short period in service and my client had pursued a warranty claim with the manufacturer. The manufacturer rejected the warranty claim on the basis that the failure had been caused by contamination of the hydraulic fluid. The foundation for this assessment was scoring damage to the valve plate.
I was asked recently to give a second opinion on the cause of failure of an axial piston pump. The hydraulic pump had failed after a short period in service and my client had pursued a warranty claim with the manufacturer. The manufacturer rejected the warranty claim on the basis that the failure had been caused by contamination of the hydraulic fluid. The foundation for this assessment was scoring damage to the valve plate.
The Maintenance Scorecard is the first book to seriously tackle the issue of aligning asset management with other areas of corporate activity. This is a particularly relevant topic given the growing importance of the area as a source of strategic advantages and as a centre for risk management.
The Maintenance Scorecard is the first book to seriously tackle the issue of aligning asset management with other areas of corporate activity. This is a particularly relevant topic given the growing importance of the area as a source of strategic advantages and as a centre for risk management.
Too many organisations neglect the benefits of a clearly defined prioritisation system. Even when they realise the importance the focus is invariably at a department or functional level. I have seen organisations where there are up to three or more prioritisation systems. None of which are inter-related. Along with work order classification, failure coding and integration with business processes, this is one of the key determinants of a maintenance systems future operation.
Too many organisations neglect the benefits of a clearly defined prioritisation system. Even when they realise the importance the focus is invariably at a department or functional level. I have seen organisations where there are up to three or more prioritisation systems. None of which are inter-related. Along with work order classification, failure coding and integration with business processes, this is one of the key determinants of a maintenance systems future operation.
It’s common knowledge that increasing the share of planned maintenance over the time spent on breakdowns should be a top priority for forward-thinking maintenance organizations. The financial benefits of that strategy, however, may not be readily apparent.
It’s common knowledge that increasing the share of planned maintenance over the time spent on breakdowns should be a top priority for forward-thinking maintenance organizations. The financial benefits of that strategy, however, may not be readily apparent.
Scheduled shutdowns, however, can provide unique opportunities to a maintenance department not normally available during standard operation or even during short shutdown periods. Lost capacity can be restored to an overtaxed facility during an extended shutdown. Major equipment overhauls can be performed to help prevent future unscheduled shutdowns. Government mandated inspections and repairs can be accomplished during a shutdown, bringing a plant into better compliance.
Scheduled shutdowns, however, can provide unique opportunities to a maintenance department not normally available during standard operation or even during short shutdown periods. Lost capacity can be restored to an overtaxed facility during an extended shutdown. Major equipment overhauls can be performed to help prevent future unscheduled shutdowns. Government mandated inspections and repairs can be accomplished during a shutdown, bringing a plant into better compliance.
Cutting costs has become a high priority, due to the recent economic conditions. Maintenance shutdowns are a major part of the annual budget at most mills, and are usually a target for cost reduction. Maintenance shutdown costs can be reduced by 30-50 percent from historical levels, with start up after the outage occurring smoothly and predictably. Using simple and effective shutdown management techniques can result in such improvements, creating savings equal to several weeks of additional production each year. This can be done without sacrificing any work, or canceling any scheduled downtime.
Cutting costs has become a high priority, due to the recent economic conditions. Maintenance shutdowns are a major part of the annual budget at most mills, and are usually a target for cost reduction. Maintenance shutdown costs can be reduced by 30-50 percent from historical levels, with start up after the outage occurring smoothly and predictably. Using simple and effective shutdown management techniques can result in such improvements, creating savings equal to several weeks of additional production each year. This can be done without sacrificing any work, or canceling any scheduled downtime.
In its simplest form, vibration can be considered to be the oscillation or repetitive motion of an object around an equilibrium position. The equilibrium position is the position the object will attain when the force acting on it is zero. This type of vibration is called "whole body motion", meaning that all parts of the body are moving together in the same direction at any point in time.
In its simplest form, vibration can be considered to be the oscillation or repetitive motion of an object around an equilibrium position. The equilibrium position is the position the object will attain when the force acting on it is zero. This type of vibration is called "whole body motion", meaning that all parts of the body are moving together in the same direction at any point in time.
A number of changes are occurring in the Condition Based Maintenance (CBM) market and in the realm of communications, Internet and database technologies that are resulting in the adoption of Internet based monitoring programs. The following paper will describe the technologies involved as well as the current market climate that is driving this change. This paper will focus on vibration analysis in particular, however, the forces involved are just as applicable to other CBM technologies and Maintenance planning packages.
A number of changes are occurring in the Condition Based Maintenance (CBM) market and in the realm of communications, Internet and database technologies that are resulting in the adoption of Internet based monitoring programs. The following paper will describe the technologies involved as well as the current market climate that is driving this change. This paper will focus on vibration analysis in particular, however, the forces involved are just as applicable to other CBM technologies and Maintenance planning packages.
Ultrasonic technology (UT) has become widely accepted for the detection of leaks in both pressurized and nonpressurized systems. Most compressor service companies and several manufacturers own some type of ultrasonic sensor for pinpointing leaks. It is easy to cost-justify the purchase of an ultrasonic sensor based upon the high cost of energy loss due to leaks. However, there is another application for ultrasound that consumers, nondestructive testing (NDT) organizations, and even developers and manufacturers of ultrasonic sensors are often not aware of or overlook. UT can be used as a means to detect early wear of components such as bearings and gears due to lack of lubrication or overlubrication.
Ultrasonic technology (UT) has become widely accepted for the detection of leaks in both pressurized and nonpressurized systems. Most compressor service companies and several manufacturers own some type of ultrasonic sensor for pinpointing leaks. It is easy to cost-justify the purchase of an ultrasonic sensor based upon the high cost of energy loss due to leaks. However, there is another application for ultrasound that consumers, nondestructive testing (NDT) organizations, and even developers and manufacturers of ultrasonic sensors are often not aware of or overlook. UT can be used as a means to detect early wear of components such as bearings and gears due to lack of lubrication or overlubrication.
Using lubrication and oil analysis to enhance machine reliability is really too simple. Behind the appearances of complexity and vale of high science are the most basic of concepts. We can try to make it difficult, but why? With the right tools and a generous amount of training, a seemingly challenging task can be transformed into something almost mundane, but still powerful.
Using lubrication and oil analysis to enhance machine reliability is really too simple. Behind the appearances of complexity and vale of high science are the most basic of concepts. We can try to make it difficult, but why? With the right tools and a generous amount of training, a seemingly challenging task can be transformed into something almost mundane, but still powerful.
Making money, not tons, has become the mantra of the pulp and paper industry in recent years. Consolidation moves in the sector have resulted in more effective management of inventories and supply, but the cyclical tendencies of the business remain. On top of that, the market is now a global one rather than being split up into regions. Managers today have to live up to the challenge of reducing costs to remain competitive in this global market. Mills face the real possibility of closure if manufacturing costs are no longer competitive in the global market economy. Future success will be achieved only by driving down costs and improving operating efficiencies.
Making money, not tons, has become the mantra of the pulp and paper industry in recent years. Consolidation moves in the sector have resulted in more effective management of inventories and supply, but the cyclical tendencies of the business remain. On top of that, the market is now a global one rather than being split up into regions. Managers today have to live up to the challenge of reducing costs to remain competitive in this global market. Mills face the real possibility of closure if manufacturing costs are no longer competitive in the global market economy. Future success will be achieved only by driving down costs and improving operating efficiencies.
