From sleep deprivation to dump truck safety: Maintenance Expo has it all
The 975 attendees at the Minnesota Spring Maintenance Expo were treated to two days packed with training and technology sharing. General sessions, concurrent sessions, and a large vendor display were staged inside the St. Cloud Civic Center as part of the April 18-19 gala. The Minnesota T2/LTAP Program cosponsored the event with Mn/DOT, the Minnesota Local Road Research Board, the Minnesota Street Superintendents Association, the Minnesota Public Works Association, and the Minnesota Highway Safety and Research Center.
Each afternoon, expo participants had the opportunity to talk to vendors about new products and operate new equipment at the outdoor equipment demo held at the Minnesota Safety Center south of St. Cloud. The new all-terrain vehicle (ATV), motor grader, backhoe, Bobcat(R), and tractor-mounted tree/brush cutter saw (mounted at the end of a long arm) were some of the most popular pieces of equipment.
A one-hour slide presentation by Doug Weiszhaar, deputy commissioner of Mn/DOT, on the experiences of and sites visited by the Minnesota delegation to Siberia last winter led off the expo. (See the winter 2001 Exchange for an article about their visit.)
Following Weiszhaar's presentation was a discussion about the challenges and opportunities presented by the changing workplace. Attendees were told: * One in four of today's total U.S. population is Asian, Hispanic, black, Native American, or other non-white group, and in the year 2050 the ratio will be one in two.
- Fifty-one percent of the U.S. workforce will be over the age of 50 by the year 2010.
- Eighty-five percent of working-age women are in the labor market.
- Ninety percent of male and 35 percent of female executives under the age of 40 are parents.
- In 1970, 40.3 percent of U.S. households were made up of married couples with children under age 18, and in 1995 it was 25.5 percent.
- New Mexico and California are the two most racially and ethnically diverse states in the United States, and Maine and Vermont are the least diverse.
Sleep deprivation
During the first day's concurrent sessions, participants were given the opportunity to learn about topics such as as sleep deprivation and its effect on drivers. Inadequate rest, sleep loss or disrupted sleep, excessive physical activity, displaced biological rhythms, and excessive mental or cognitive work all contribute to fatigue, and the USDOT estimates 100,000 vehicle crashes annually are linked to drowsy driving. Individuals must evaluate their personal risk of contributing to this commonly ignored problem. Taking sedative medications, working more than 60 hours per week, working more than one job, driving alone or on a long, rural, dark, or boring road, or, if your main job involves shift work, drinking even small amounts of alcohol, all contribute to increasing your risk of drowsy driving.
Studies indicate fatigue is a factor we all must be aware of. Most police are not trained to detect fatigue but law enforcement and trainers are becoming more aware of the dangers that accompany drowsy driving.
Dump truck safety
The dump truck safety and operation session was very informative. Truck- and equipment-related injuries account for nearly 50 percent of all deaths in the workplace, and out of 2,000 occupations, truck drivers had the most lost workdays. Driver responsibility, pre-operation checks, and safe loading and unloading were just some of the items touched upon. Checking air and brake systems was also given detailed coverage.
Defensive driving
Wednesday's concurrent sessions were followed by a defensive driving presentation that addressed some of the most frequent contributing factors for motor vehicle crashes in Minnesota. Those factors include inattentive driving, illegal or unsafe speed, physical impairment, failure to yield, following too closely, disregarding a traffic control device, and improper lane usage, along with overall aggressive driving. Each of these contributing factors, and the importance of seat belt usage, was discussed as part of an overall effort to prevent the common driver errors that often result in motor vehicle crashes in Minnesota.
One of the newer concepts presented was the "three-second rule" and "three-second-plus rule." The National Safety Council recommends these rules as formulas for preventing many of the rear-end collisions caused by motorists following too closely.
The three-second rule replaces the old two-second rule as a guideline for recommended following distance. The rule is simple to apply. When the rear bumper of the vehicle in front of you passes a stationary object alongside the roadway, start counting to yourself. If the vehicle you are driving passes that stationary object before the count of three, adjust your following distance accordingly. During adverse driving conditions such as rain, darkness, or following a motorcycle (a motorcycle can stop faster than a passenger vehicle), use the three-second-plus rule. The three-second and three-second-plus rules replaced the two-second and two-second-plus rules due to higher speeds.
Mn/ROAD
Concurrent sessions continued on Thursday morning with a session titled "Mn/ROAD Background and Research Results."
The Minnesota Road Research Project was built to solve real problems related to how we design, construct, and maintain our pavements. Several significant findings have emerged over the first few years of the project. Topics included:
- A new method to place spring load restrictions statewide--resulting in annual savings of approximately $15 million. *
- A new method to place 10 percent overloads during the winter months, based on a freezing index model instead of the current calendar date method. This will result in the movement of more commodities and less damage to our system.
- MnPAVE—this design program will be more accurate and allow for more precise materials characterization than the current process and will annually save counties, cities, and Mn/DOT millions of dollars when it is fully implemented (see article).
- New devices to measure in-situ stiffness of subgrade and base materials.
This study will result in improved methods to ensure that these materials are meeting construction specifications; methods will be less labor-intensive and more accurate than the current practice.
Backhoe operator safety
Topics covered included the machine, pre-operation checks, and excavation and job site safety. It is extremely important for the operator to know the operator controls, the machine and its capabilities, and how to properly position the machine. Job site safety depends on knowing where all utilities are located. Call Gopher One at least 48 hours in advance, know the legal description and nearest intersecting highway of the job site, and use white paint to mark out proposed excavation. Keep the ticket issued number, and remember Gopher One Locates are for commercial lines only.
Every excavation site needs a "competent person." A competent person is defined as someone who is capable of identifying existing and predictable hazards in the surroundings, or working conditions that are unsanitary, hazardous, or dangerous to employees, and who has the authorization to take proper corrective measures to eliminate them. The keys to excavation safety are: know your soil types, slope ratios, means of egress (every 25 feet), and air quality (4-foot-depth rule), and maintain a 2-foot-minimum distance from trench sides with all excavated material and equipment.
Ditch clean-out
Expo attendees were reminded that ditch clean-out procedures should follow the National Pollutant Discharge Elimination System (NPDES) and Standard Specifications for Construction requirements. The new 2000 specifications state that any land disturbance that could impact a water of the state must comply with erosion and sediment control practices as outlined in 1803.5. Ditch construction has changed from practices performed years ago and now includes improved hydraulic analysis, geotextiles, engineered sod, and other changes.
Reconstruction must follow and recreate the design intent. This requires understanding not only how the ditch was designed but also how it was constructed. Ditch sleuthing needs to be performed to learn the construction history and methods, grade, flow (cubic feet per second) and flow direction (not as simple as it may seem), and other sediment buildup causal agents including degraded pipe.
When ditches must be cleaned instead of just mowing down the cattails, all materials and staging operations must be considered before any work begins. It seems no matter what we do, a 10-year storm event soon follows and makes the situation even worse. The presentation went over criteria for ditch clean-out, plan of action, construction specifications (2573, 2575, 3677, 3876, 3882, 3884, 3885, 3886, 3888) and techniques, seed mixes (28B, 50B, 80B, sod) and general guidelines. These guidelines include mowing cattails once in late June through July, removing debris, monitoring, determining if there are needed permits, using surveys to correct the grade, and properly disposing of the sediments and other materials.
Preventive equipment maintenance
The historical development of equipment preventive maintenance as well as the differences among preventive maintenance, breakdown maintenance, and predictive maintenance were presented. Operation costs of publicly owned equipment are competitive with the private sector. Costs can be kept to a minimum if repairs are made during scheduled down time, an oil analysis is made, inspection forms are used during inspections, wheel and tire maintenance is done on a regular basis, and air chambers and slack adjusters are regularly inspected, cleaned, and adjusted. The bottom line is the importance of preventive maintenance in keeping the costs for equipment repairs and maintenance to a minimum.
Concrete block retaining walls
The session on concrete block retaining walls proved to be very informative for public employees as well as for private property owners who have, or plan to construct, a concrete block retaining wall.
More than one hundred segmental concrete block retaining walls along roadways in the Twin Cities were surveyed to determine the extent of any apparent durability problems and to gain additional insight into the nature of the deterioration. Six different firms manufactured the blocks included in the survey. A selected summary of the survey findings, conclusions, and recommendations follows:
- Of the walls surveyed, 93 percent were in fair or better condition.
- Incidence of freeze-thaw damage, scaling, and some other distresses was strongly correlated with specific manufacturers and block designs.
- Poor durability problems were directly related to lack of durability of the wall units. This suggests inappropriate mix designs and/or use of non-durable aggregate.
Block manufacturers need to investigate and improve, where necessary, the durability of the materials and mixes used in their masonry block units. Quality control improvements to reduce production and distribution of non-durable masonry units are another consideration. Also discussed was developing realistic acceptance/rejection tests for more accurately predicting field performance potential.
Mn/DOT issued Technical Memorandum 01-05-MMR-01 in response to the survey; it governs all projects let after March 1, 2001. The memorandum sets new limits on where block walls may be used, establishes new strength and freeze-thaw requirements, and establishes a new surface-sealing requirement.
--Henry Grothaus T2 support engineer