URBAN ROAD DESIGN Lecture 10 Design of Grade
URBAN ROAD DESIGN Lecture 10 - Design of Grade Separation-Ⅱ School of Civil Engineering 孙仁娟 2012. 4. 24
• The High Five in Dallas, Texas, USA: an extreme example of interchange design. This is a complicated five-level stack interchange due to the close proximity of frontage roads.
Why should design interchange?
Objectives • Learn some grade-separated intersection design standards, specification, guidelines; • Identify and compare grade-separated intersection/interchange types, advantages/disadvantages; • Identify and describe grade-separated intersection/interchange design procedures and principles.
Terms • Grade separation/Grade separated intersection is the process of aligning a junction of two or more transport axes at different heights (grades) so that they will not disrupt the traffic flow on other transit routes when they across each other. • Interchange: is a road junction that typically uses grade separation, and one or more ramps, to permit traffic on at least one highway to pass through the junction without directly crossing any other traffic stream.
• • • Stack interchange Cloverleaf interchange Cloverstack interchange Turbine interchange Roundabout interchange Diamond interchange Other/hybrid interchanges Trumpet interchanges Directional T interchange
• Diamond
Standard and Specification 《城市道路交叉口规划规范》GB 50647 -2011，2012年 1月1日 Code for Planning of Intersections on Urban Road 《城市道路 程设计规范》 CJJ 37 -2012, 2012年 5月1日 Code for design of urban road engineering 《城市道路交叉口设计规程》CJJ 152 -2010，2011年 3月1日 Specification for design of intersections on urban roads
Type and type selection
Type and type selection
Design parameters • Determination of design speed is based on the design speed of main carriageway, interchange class, and type of ramp • (设计车速应根据主线，立交等级和匝道型式确定)
Design parameters • LOS
Design parameters
2. Ramp • Right turn ramp （右转匝道）
2. Ramp • Left turn ramp
2. Ramp Horizontal alignment
2. Ramp
2. Ramp Profile/Vertical alignment • 立交匝道最大纵坡不应大于表规定。
3. Collected and distributed lanes
4. Auxiliary lane
5. Anciliary facilities • 1
5. Anciliary facilities
Questions?
- Slides: 50
