Everyone knows about bicycles. Like any sport, they have a fandom following, from avid Tour-de-Francers to all those dedicated bike-to-workers. Not to mention, it’s practically a rite of passage to learn how to ride one, and it’s the quintessential comparison when talking about things you never forget how to do once you learn.
Despite their popularity around the world, America still shines with its youthful glow in comparison to many historic countries; we just don’t have the same bicycle-laden streets that other countries have grown to cherish. That’s not to say that America isn’t making strides to enhance its bike-ability. Major cities have hundreds of miles of bike lanes, while New York City tops the list at having 1,000 miles.
Though America has some catching up to do, cities have seen overall betterment in roadway safety when communities define where bicyclists should travel on the roads.
One innovative design that’s gaining traction is the bicycle box. From the NACTO website, “A bike box is a designated area at the head of a traffic lane at a signalized intersection that provides bicyclists with a safe and visible way to get ahead of queuing traffic during the red signal phase.”
Bicycle boxes are innovative because they address many safety concerns at once, such as: increasing visibility of bicyclists, preventing “right-hook” conflicts, provides priority for bicyclists, and groups bicyclists into one obvious area, making it easier for cyclists to clear the area quickly.
Recognizing these benefits, Hoyle, Tanner recently designed a bicycle box system on Farrell Street in South Burlington, Vermont, which will become the first approved installation in the State. As Farrell Street is part of the route of the Champlain Bikeway (a 363-mile scenic loop around the lake), the City is dedicated to improving access and safety in this location and throughout the City. At the Farrell Street/Swift Street intersection, the City was particularly concerned that southbound cyclists looking to make a through or left turn would conflict with vehicles turning right to access US 7 & I-189. A bicycle box was the perfect solution. Hoyle, Tanner worked with the Federal Highway Administration (FHWA) and gained interim approval for the City’s use of this valuable tool, which is required for new traffic control devices that have not yet been formally adopted. Partnering with Howard Stein Hudson, Hoyle, Tanner designed the bicycle boxes which will employ special highly visible green pavement markings and thermal or video bicycle detection to reduce collisions and improve safety at the intersection. With this experience, Hoyle, Tanner will look to aid other municipalities and state agencies with this and other emerging traffic control technologies, with a goal of improving the recreational and commuter transportation experience for all users.
Preventative maintenance is defined as scheduled work at regular intervals with the goal to preserve the present condition and prevent future deficiencies. On bridge structures, this work is typically performed on structures rated in ‘fair’ or better condition with significant service life remaining. Minor repairs may be necessary to maintain the integrity of the structure and prevent major rehabilitation. Structures that are not maintained are more likely to deteriorate at a faster rate and require costlier treatments sooner than maintained structures; therefore, it is more cost effective to maintain structures to avoid replacement or major rehabilitation needs.
New England’s weather causes extreme conditions for steel bridge trusses, such as flooding, ice and snow. Corrosive de-icing agents are used in the winter, which can accelerate deterioration of exposed bridge elements. Preventative maintenance is critical for steel truss bridges to reach their intended design service life and, therefore, attain the lowest life-cycle cost of the bridge investment. Presented are minimum recommended guidelines for preventative maintenance of steel truss bridges.
Here are 14 actionable maintenance tasks to preserve historic truss bridges:
- General: Remove brush and vegetation around structure. Annually.
- Bridge Deck & Sidewalks: Sweep clean sand and other debris. Power wash with water to remove salt residue. Annually.
- Wearing Surface: Check for excessive cracking and deterioration. Annually.
- Expansion Joint: Power wash with water to remove debris, sand and salt residue. Annually.
- Bolted Connections: Inspect for excessive corrosion or cracking of the steel fasteners. Check for any loose or missing bolts. Annually.
- Welded Connections: Check for cracking in the welds. Annually.
- Truss Members: Power wash with water to remove sand, salt and debris, particularly along the bottom chord. Give specific attention to debris accumulation within partially enclosed locations such as truss panel point connections or tubular members. Annually.
- Bridge Seats: Clean around bearings by flushing with water or air blast cleaning. Annually.
- NBIS Inspection: Complete inspection of all components of the steel truss bridge. Every 2 years unless on Red List.
- Painted Steel: Scrape or wire brush clean, prime and paint isolated areas of rusted steel. Every 2 to 4 years.
- Steel Members: Check for rust, other deterioration or distortion around rivets and bolts, and elements that come in contact with the bridge deck which may be susceptible to corrosion from roadway moisture and de-icing agents. Every 3 to 5 years.
- Bearings: Remove debris that may cause the bearings to lock and become incapable of movement. Check anchor bolts for damage and determine if they are secure. Every 3 to 5 years.
- Exposed Concrete Surfaces: Apply silane/siloxane sealers after cleaning and drying concrete surfaces. Every 4 years.
- Bridge & Approach Rail: Inspect for damage, loose or missing bolts, sharp edges or protrusions. Every 5 years.
Actions to Avoid
- Do not bolt or weld to the structural steel members.
- Do not remove any portion of the structure.
- CAUTION! Paint may contain lead.
Additional resources can be found through the New Hampshire Division of Historical Resources website.
Pi… I did not forget the “e”, I am referring to the mathematical constant, π, for the value 3.141592…, a ratio of the circumference of a circle to its diameter. For some it was junior high and others it was high school, but almost everyone is taught the concept of Pi in geometry class in America. The staggering question asked by so many students over the years is “how do we use this in ‘real’ life?” Well we have answered that question for all of you as it relates to engineering:
When designing bridges many of the structures utilize reinforced concrete to provide the strength necessary to support its daily use by vehicles. For many of our bridge projects, the circle is most often representing the area of reinforcing steel used in the reinforced concrete beam. We determine the total amount of the (steel) reinforcing to determine the capacity of a structural member such as a beam, deck or slab.
In associated roadway design, Pi is used in a slightly different manner, to calculate curvature. A maximum curvature (minimum radius) is used to ensure adequate sight distance at differing speed limits. This promotes safe vehicular travel by providing a level of comfort and expectation to the driver.
Another application for the mathematical constant is in airfield markings. Their purpose is simple – to safely guide pilots during aircraft take-offs and landings, and while taxiing around the airfield. To create these markings, Pi is utilized when calculating the amount of airfield paint required for runway designation markers, taxiway centerlines and edge lines.
Pi is also used extensively in the calculation of areas of gravity sewers, wastewater force mains, water main pipes, storm drains, drainage culverts and other types of utility pipes. These calculations are used to establish the area of the pipe for the purpose of determining flow velocities and flow volumes as well as other types of hydraulics calculations.
Now that we have proved your mathematics teacher correct, and that someday you may need to know the value of Pi, the obvious question remaining is “what does pi and pie have in common?” My answer is Pi is focused on circles, radius and diameters… and so does pie! If you want a great Chocolate Cream Pie recipe check this out!