Post on 19-Jan-2016
Urban Storm Drain Design: Junction box standards
Junction box standards• Highlight various parts of Manhole Type M
standards and specification sheet.• Identify “things” that may confuse
• Feel free to mark on the sheet in your participant manual.
Junction box standards
Similar to inlet considerations, rebar important. Sometimes can join boxes to maintain orientation If box over 6 feet wide -- special case , call BRG.
Junction box standards
Riser does not have to be different dimension than the box
Junction box standards• Make as many elements as possible identical
• Enhance constructability• Min/max dimensions: maximum is structural
limitation, if must exceed call BRG for guidance.• D+1 ft. becomes limiting with box structures – they
can get wide
Junction box standards
• Try to make elements identical and repeatable• 1 set inlet, 1 set laterals, 1 junction
Junction box standards
• Offsets are not a constraint. • Can have multiple offsets.• Can have multiple penetrations on a side.
Junction box standards
• When have high topographic relief, use drops in junction boxes to control energy and velocity.
• Try to keep time of travel in system similar to pre-development conditions.
• d/D, Q, and V tells us where we need to change D as move through the system.