Member $99.00 | Non-Member $159.00
Sponsored by ASCE Continuing Education and the Transportation & Development Institute (T&DI).
INSTRUCTORS:
Gordon R. Keller, P.E., G.E., M.ASCE
Donald Lindsay, P.E., G.E., PG, CEG
Purpose and Background
Low-volume roads make up 60 to 70 percent of all roads worldwide. In the United States, there are over 2.5 million miles of low-volume roads. On those roads, major investments are made in the materials used for surfacing and in drainage crossing structures such as culverts, fords, and bridges. Thus understanding the many aspects of roadway drainage is important to achieve good designs, to protect our investment in the roads, to minimize damage and maintenance needs, and to protect water quality near the road and at crossings.
As the old saying goes, three of the most important aspects of road design are Drainage, Drainage, and Drainage! This webinar will address those aspects. Many road surface drainage techniques exist to keep water off the road surface and to avoid concentration of water. These include maintaining a good crown on the road or establishing an in-sloped or out-sloped profile. Frequent culvert cross drains, rolling dips, lead-off ditches, drop inlets, and other measures help avoid excessive water accumulation and associated damage.
Most road systems have hundreds to thousands of culverts, many very old, and many that have failed and have been replaced at some time. Proper culvert sizing is critical, along with proper installation, alignment, bedding and compaction, use of headwalls and end sections, etc. They may need protection against plugging or the damage from overtopping or bank erosion. Properly designed low-water crossings can offer a cost-effective alternative to culverts in some circumstances, especially on low-volume roads. Finally, bridges are a huge investment and are key structures to keep roads open. Maintaining adequate hydraulic capacity and protection against a variety of scour problems (the most common cause of bridge failure) is critical. Other key bridge issues are channel debris, approach stream-bank stabilization, and changes in the channel, all of which can be mitigated.
Primary Discussion Topics/Outline
- Introduction to low-volume road drainage issues
- Roadway surface drainage measures
- Key culvert design and installation factors
- Techniques to avoid culvert failures and damage
- Use and design of fords and low-water crossings
- Key bridge location, design, and maintenance issues
Learning Outcomes
- Upon completion of this webinar, learners will be able to identify the four basic drainage issues common on low-volume roads.
- Based on the webinar information, listeners will be able to successfully identify road surface drainage problems and describe several corrective measures.
- Based upon the webinar information, participants will be able to correctly describe at least three important design and installation considerations for culverts.
- Upon completion of this webinar, participants will be able to describe the advantages of each major type of drainage crossing structure, that is, a culvert, a ford or low-water crossing, and a bridge.
- Upon completion of this webinar, listeners will be able to name at least three important issues in low-volume road bridge design
Webinar Benefits
- Understand the importance of keeping water off the road surface
- Learn how to properly avoid water concentration and to drain the road
- Understand the most important issues in culvert design and installation
- Prevent culvert failures, particularly plugging
- Learn how to design and properly use low-water crossings
- Understand what is most important in designing and protecting a bridge, particularly against scour
Intended Audience
Civil engineers, road managers, maintenance personnel, field technicians, and hydrologists involved in the planning, design, maintenance, repair, and management of low-volume roads and their drainage crossing structures will benefit from this webinar.