Preventive maintenance programs keep your bridges open for years to come
Jan Herbst, P.E., Director of Public Works, Pinellas County, Florida; Rick Ruiz, Assistant Director of Public Works, Alameda County, California; and Harry Lorick, P.E., PTOE, Principal, LA Consulting, Inc., Manhattan Beach, California; Presenters, 2007 APWA Congress
Bridges are intricate structures with structural, mechanical, electrical and civil components. The structures, whether fixed or movable facilities, require regular preventive maintenance to remain in optimal operational condition. This discusion outlines how two counties—one in California and one in Florida—have implemented an organized approach to successfully accomplish their regular preventive bridge maintenance.
Alameda and Pinellas Counties
Alameda County in California and Pinellas County in Florida use an organized preventive approach for bridge maintenance that is supplemented by computerized maintenance management systems. These systems are used to implement the basic principles of Planning, Organizing, Directing and Controlling as applied to maintenance. Both counties are bay counties with Alameda in the San Francisco Bay and Pinellas located in Tampa Bay, yet are separated by 2,600 miles.
Alameda County has six movable bridges with roads that are traveled by 35 to 45 million vehicles annually with a population of 1.5 million people in 738 square miles. Alameda County's fixed bridges are the responsibility of other departments. Pinellas County has a structural inventory that encompasses 4 bascule bridges and 134 fixed bridges in total, and is the most densely populated county in the State of Florida with a population of 0.9 million in 280 square miles.
The Public Works Department in each respective county is responsible for the maintenance needs of various infrastructure components including bridges. Their geographical locations (e.g., Florida is semi-tropical; much of California's climate is temperate) affects the overall maintenance efforts for bridges due to the varying conditions, yet the approach is the same.
Bridges are often the most valuable assets that an agency owns with direct impact to the traveling public. Further, bridges provide accessibility for security and safety programs and agents that are of paramount importance for the proper integration with a transportation system. They are, therefore, some of the most visible assets. The recent perspective of many agencies is that these structures have a long life and little preventive maintenance is needed; yet, from the perspective of a risk assessment and traffic effects, bridges should receive much more attention. For example, one urban county owns 1,200 miles of roads and 384 bridges where each asset component class is worth about $500 million. The county has appropriated 96 workers for the roads, yet only 5 for the bridges! Often bridges are not allocated resources to protect their values, and preventive maintenance is not a priority. The functional loss of the bridge not only is a loss of the asset's value, but a loss of access and possibly reduced travel opportunities for commercial, industrial and residential areas, as well as the general public. The economic impact to the surrounding area can be significant.
The risks associated with bridges can be mitigated with the implementation of a preventive maintenance system and even further through the integration of a modern maintenance management system. Maintenance of bridges, whether fixed or movable, is more cost effective than retroactive replacement or repair of the existing structure by an order of magnitude. The usage of modern maintenance management systems (MMS) has helped two counties track and improve their bridge maintenance. In this process each county has gained the ability to ensure safety and longevity of some of their most expensive assets, at a much lower life cycle cost than those for replacement or major retroactive repair actions by being proactive.
This discussion describes the process to achieve this result.
Inspections and asset condition assessments are the first steps in a bridge preventive maintenance program. Inspection provides a visual evaluation and determination of the relative condition of each bridge and its related components. It is a tool to determine types of treatments and actions that should be performed. Inspections for bridges are required for all public vehicular bridge structures with a span of greater than 20 feet and are performed by state highway departments on a biannual basis as required by federal statute. Other facilities such as pedestrian bridges and vehicular structures less than 20 feet in span are not mandated for inspection, but are often done by owner agencies. In Pinellas, the nonfederal-status bridges are inspected on the same frequency as statute bridges.
Inspections are performed to collect specific criteria according to a defined process. They yield a general recommendation of maintenance or rehabilitation, but do not provide recommended treatment types. A rating system, called a sufficiency level (Figure 1), is derived from four criteria: structural adequacy and safety; serviceability and functional obsolescence; essentiality for public use; and special reductions. Once inspections are made, all data is reported to the Federal Highway Administration (FHWA). Following one of our examples, Alameda County in California receives a sufficiency rating of 58.2% as compared to the national average of 47.5%.
Areas of maintenance around a bridge include signage, waterways, approaches, substructures, superstructures, and the road deck itself. These areas have the potential of requiring either structural or nonstructural maintenance. Many nonstructural maintenance treatments are low cost and directly contribute to extending the life of the bridge, when executed in regular intervals. Areas considered to be nonstructural maintenance include debris cleaning, sweeping, joint cleaning and repair, scupper or drainage cleaning, crack filling, deck patching, and guardrail repair. For movable bridges, often the manufacturers of the mechanical components of the bridge are responsible for identifying maintenance needs.
It is understood that bridges, like all assets, will eventually need to be replaced at some point. However, the extension of the life of a bridge in structural, nonstructural, electrical and mechanical areas can occur through preventive maintenance practices. Nonstructural preventive maintenance can alleviate the need for structural preventive maintenance. Timing in these cases is of the utmost importance with savings benefits potentially reaching into the millions of dollars per bridge.
Many agencies perform routine maintenance including such actions as crack filling and sealing, pothole filling, overlays, checking bridge abutments, cleaning scuppers, checking joints and bearing pads, and painting. These principles of maintenance are generally accepted when applied towards regular roads, so the same can be applied towards bridges to recognize benefits. For example, clearing debris and ensuring positive drainage can prevent moisture retention which can corrode steel and/or impact joints.
In order to apply routine preventive maintenance to bridges with mechanical or electrical components, a greater level of understanding and effort may be required to properly carry out actions. Generally, maintenance on these types of bridges is carried out as per the manufacturer's instructions, and would vary on an individual basis, where an understanding of systems might be required. Original documentation may be missing in some cases, causing the need for experts or consultants to put together an acceptable routine. General types of routine bridge maintenance are listed in Figure 2.
Systems and PM Programs
Even if it is known what is to be done to bridges to maintain them correctly, questions naturally arise: "When and how often should the work be performed?"; "Are there enough people?"; "What are the budgeting needs?"; "How can maintenance be monitored?"; and "How can the results be quantified?" Some of the tools that are available include referencing best work practices, having a routine preventive maintenance activity-based work plan in place, scheduling the work and documenting when and how it was performed, and having methods in place to monitor the processes and make adjustments. All of these are components of the basic general management principles of Planning, Organizing, Directing and Controlling (Figure 3).
The planning process has an agency determine major activities, define guidelines and work methods with work unit measurements, collect resource information, perform condition assessment, determine desired level of effort, and compute an activity-based budget. Activity-based plans have three benefits: they show how many resources are necessary throughout the year; they allow for proper budgeting though estimation; and they allow for the justification of the proper amount of labor to be allocated to maintenance efforts. The agency can plan the estimated amount of preventive and reactive maintenance required for a fiscal year. Utilizing existing work history data can greatly increase the accuracy of the plan.
The organization process has the agency utilize the outputs from the planning process to determine staffing, equipment and material needs. Utilizing the activity-based plans with the estimated levels of service and the anticipated times of year that each activity is performed, information regarding when specific resources are required. This can be used to establish periods of the year when an agency may need additional resources to complete the anticipated work.
The directing process has the agency schedule and perform the work. Scheduling provides for the ability to proactively plan work into routine cycles, usually based upon a two-week outlook or schedule. Scheduling also allows for the use of service requests, work orders, and other reactive maintenance with the possibility of non-emergency maintenance being performed with routine maintenance.
The monitoring and controlling process occurs once work is performed. Work is tracked using a standard method within the agency by recording labor, equipment, materials, additional costs, and accomplishment amounts. Data recorded can be used to generate reports to determine the amount of work accomplished, the resources utilized, the productivity of the staff, and the cost effectiveness of work performed. This data can then be used for planning the next year.
All of these efforts establish a system of continuous improvement. Through the use of modern computerized maintenance management systems, a more predictable outcome of labor cost, time spent, scope of work and frequency can be obtained when combined with the use of methodical approaches.
System Selection and Development
In deciding to select a computerized maintenance management system, a formal selection process was utilized to determine the best software to assist each agency's maintenance management system. Each agency selected a separate software package: Alameda selected MaintStar(tm) software and Pinellas selected Agile Assets(tm) software. Neither of the selected software packages was created solely for bridge maintenance, but rather for the implementation of computerized maintenance management. Both counties were able to configure, establish and deploy a complete MMS system that tracks all maintenance data, establishes routine preventive maintenance schedules, produces a performance-based annual plan of work, creates short-term schedules, and allows for the counties to monitor productivity and cost.
Both Alameda and Pinellas Counties used a similar approach to implementing their system. The first step was to establish the work activities performed and a clear definition of the work to be performed. The work method was then documented with the amount and types of resources to be used on average for each day's worth of work. This also included the average amount of work that was anticipated to be completed in a given day. The result was a set of activity guidelines for all bridge maintenance. Using these activity guidelines in conjunction with historic work trends and work amounts derived from state inspections, bridge plans for annual work provided budgets and estimated resource quantities required throughout the year. Each county then had a fully justifiable activity-based budget that is updated on an annual basis.
Alameda County outlines maintenance tasks each quarter and all projected work to be performed based upon activity. In addition to the quarterly outlines, all estuary bridge work is planned a year in advance based on the work history, inspection and agency's goals. On an overall system level, preventive maintenance work is tracked and generated by asset through the MaintStar software in place. For all pumping stations, a schedule and routine exists for each station with a similar format, though each station has a unique preventive maintenance sheet that varies slightly each month. These sheets are divided biweekly, monthly, quarterly, semiannually and annually. Check boxes are provided on the form as an easy way to manually track preventive maintenance completion. These sheets are stored at each pumping station in a binder, and copies of them are sent each month to supervisors for review. Each pumping station also has a logbook to record daily activities or make general notes. At the end of each year, preventive maintenance sheets are collected and filed away by each supervisor.
Types of manual preventive maintenance documentation in Alameda County vary per bridge in terms of format and tasks, but are generally similar for familiarity purposes. Examples of routines for Alameda's estuary bridge preventive maintenance are included for bridge tenders, safety, maintenance, and mechanical, electrical and yard equipment. All of these routines are integrated into the MaintStar software.
Pinellas County also has a routine maintenance database established that contains information on preventive maintenance types and cycles for each bridge asset. All applicable preventive maintenance activities are listed with the estimated amount of time to perform. Additionally, the frequency of the preventive maintenance and the estimated priority, based upon inspection recommendation, are listed and printed with the assignment of work. All aspects of their preventive maintenance program work together as part of a larger complete maintenance management system, which in addition to the proactive tasks includes reactive tasks as well.
Alameda and Pinellas both schedule their work in biweekly increments. Every two weeks the bridge supervisors schedule all anticipated work for all crews including a combination of routine preventive maintenance work and other reactive maintenance. Schedules are created to allow the performance of work at the same bridge or locations within close proximity to minimize travel times. Previous schedules are discussed at subsequent biweekly meetings to determine best resource allotment and to ensure adherence to the schedule. If the schedule has not been met, the crew leader or supervisor must explain the reasons, such as weather delays, unexpected leave of staff, or emergency work elsewhere. Any unfinished work is then transferred onto the next biweekly schedule.
Alameda County is controlling their maintenance processes, which gives them the ability to continually improve. Alameda's assessments contain performance measures and, via custom reports, can separate data by bridge asset, and track and compare labor activities on a per-hour basis. Work status reports are provided to the operations and maintenance director monthly to monitor planned versus actual days, unit cost, and productivity. Actual work calendar reports are also provided for the operations and maintenance director to monitor the planned versus actual average daily production as well as planned versus actual days by month throughout the year. Planned use summaries are used during annual budget updates to compare resources allotted in the activity guidelines to resources actually used.
All of these management activities have helped both Alameda and Pinellas Counties to document procedures, create routine cycles, give justification for usage of resources, and implement efficiency tools. This has allowed them to manage operations, project outputs and work needs, make them more effective and efficient, and focus on proactive maintenance, with the end result of extending the life of both counties' most valuable assets, their bridges.
Agencies can establish a preventive program to protect their valuable bridge assets using maintenance management systems. This tool, when properly used, can lead to better budgeting of funds and labor, increased control, higher quality jobs and better communication. A systematic approach to maintenance is often already in place for other assets, but it can also be of benefit to the preservation of an agency's bridge assets. Both Alameda and Pinellas Counties, through the successful implementation of a maintenance management system, have been able to better schedule work both in the long and short term, organize adequate labor resources, and track progress for a continuous improvement of preventive maintenance operations. The importance of preventive maintenance on costly assets such as bridges is realized when contrasting a good preventive maintenance program with the cost of replacement or major repair that has to be done if the life of a bridge is reduced. Bridges can cost millions of dollars and have a life of 30-50 years. Therefore, any effort to expand this life only a few years can save hundreds of thousands of dollars.
The authors will give a presentation on this topic at the 2007 APWA Congress in San Antonio. Their session is entitled "Keep Your Bridges Open for Years to Come!" and takes place on Tuesday, September 11, at 3:45 p.m. Jan Herbst can be reached at (727) 464-3829 or firstname.lastname@example.org; Rick Ruiz can be reached at (510) 670-5504 or email@example.com; and Harry Lorick can be reached at (310) 374-5777 or firstname.lastname@example.org.