Bridge: Stream Crossings - Revision history

Beichhorst at 19:31, 24 May 2017

2017-05-24T19:31:13Z

Mnemphos at 20:05, 5 December 2016

2016-12-05T20:05:19Z

Mnemphos: /* General */

2016-11-09T14:51:36Z

‎General

Mnemphos at 16:35, 2 November 2016

2016-11-02T16:35:14Z

Mnemphos: /* General */

2016-11-02T16:34:36Z

‎General

Mnemphos at 16:34, 2 November 2016

2016-11-02T16:34:04Z

Mnemphos at 16:32, 2 November 2016

2016-11-02T16:32:58Z

Mnemphos at 14:22, 2 November 2016

2016-11-02T14:22:08Z

Mnemphos at 14:20, 2 November 2016

2016-11-02T14:20:56Z

Mnemphos at 14:20, 2 November 2016

2016-11-02T14:20:52Z

@@ Line 7: / Line 7: @@
 | colspan="3" |
 =Primary Guidance=
-*This guidance covers bridges and small structures that carry streams
+*This guidance covers bridges and small structures that carry streams.
-*Stream crossings should be at a straight section of a stream, instead of at a bend
+*Stream crossings should be at a straight section of a stream, instead of at a bend.
-*Box culverts should be used for small stream crossings whenever possible
+*Box culverts should be used for small stream crossings whenever possible.
-*Pipe culverts should consist of concrete pipes, not metal pipes
+*Pipe culverts should consist of concrete pipes, not metal pipes.
-*For structures with short spans, piers in a stream should consist of piles with a concrete cap
+*For structures with short spans, piers in a stream should consist of piles with a concrete cap.
-*For Design Storm criteria, refer to Drainage/Hydraulics – Design Storm
+*For Design Storm criteria, refer to Drainage/Hydraulics – Design Storm.
 |-
 | colspan="3" |
 =Discussion=

@@ Line 36: / Line 36: @@
 |}
-[[Category:Practical Design Guidance]]
+ [[Category:Practical Design]][[Category:Practical Design Guidance]]
 =See Also=
 *[[Roadways: Culverts|Culverts]]
 *[[Practical Design Implementation Guidance|Practical Design Implementation Guidance]]

@@ Line 19: / Line 19: @@
 ==General==
-This guidance covers bridges and small structures that carry streams or other features that have been labeled as [https://www.epa.gov/cleanwaterrule/definition-waters-united-states-under-clean-water-act| Waters of the U.S] .  Bridges are defined by Federal Highway Administration (FHWA) as structures with clear spans of 20 ft. or greater.  Small structures are defined as having a clear span length or diameter of 5 ft. up to 20 ft.  Small Structures are also included in this guidance if they have a clear span length or diameter of 3 ft. up to 5 ft. with the fill over the structure being less than the clear span of the structure.  For smaller culverts or culverts that carry drainage, refer to Culverts in the Roadway section.
+This guidance covers bridges and small structures that carry streams or other features that have been labeled as [http://tinyurl.com/qapos82| Waters of the U.S] .  Bridges are defined by Federal Highway Administration (FHWA) as structures with clear spans of 20 ft. or greater.  Small structures are defined as having a clear span length or diameter of 5 ft. up to 20 ft.  Small Structures are also included in this guidance if they have a clear span length or diameter of 3 ft. up to 5 ft. with the fill over the structure being less than the clear span of the structure.  For smaller culverts or culverts that carry drainage, refer to Culverts in the Roadway section.
 ==Stream Crossings==

@@ Line 28: / Line 28: @@
 ==Pipe Culverts==
-Pipe culverts for stream crossings should consist of concrete pipes, not metal pipes, since the metal pipes have a history of deteriorating and will require major maintenance such as installing liners or paving the inverts.  Since these culverts are carrying streams or Waters of the U.S.,  stream diversions will be necessary to construct them, requiring permitting, which adds cost to a future replacement project.  Concrete pipes also have the added advantage of needing minimal cover as compared to metal pipes.
+Pipe culverts for stream crossings should consist of concrete pipes, not metal pipes, since the metal pipes have a history of deteriorating and will require major maintenance such as installing liners or paving the inverts.  Since these culverts are carrying streams or [https://www.epa.gov/cleanwaterrule/definition-waters-united-states-under-clean-water-act| Waters of the U.S],  stream diversions will be necessary to construct them, requiring permitting, which adds cost to a future replacement project.  Concrete pipes also have the added advantage of needing minimal cover as compared to metal pipes.
 ==Piers==

@@ Line 19: / Line 19: @@
 ==General==
-This guidance covers bridges and small structures that carry streams or other features that have been labeled as Waters of the U.S .  Bridges are defined by Federal Highway Administration (FHWA) as structures with clear spans of 20 ft. or greater.  Small structures are defined as having a clear span length or diameter of 5 ft. up to 20 ft.  Small Structures are also included in this guidance if they have a clear span length or diameter of 3 ft. up to 5 ft. with the fill over the structure being less than the clear span of the structure.  For smaller culverts or culverts that carry drainage, refer to Culverts in the Roadway section.
+This guidance covers bridges and small structures that carry streams or other features that have been labeled as [https://www.epa.gov/cleanwaterrule/definition-waters-united-states-under-clean-water-act| Waters of the U.S] .  Bridges are defined by Federal Highway Administration (FHWA) as structures with clear spans of 20 ft. or greater.  Small structures are defined as having a clear span length or diameter of 5 ft. up to 20 ft.  Small Structures are also included in this guidance if they have a clear span length or diameter of 3 ft. up to 5 ft. with the fill over the structure being less than the clear span of the structure.  For smaller culverts or culverts that carry drainage, refer to Culverts in the Roadway section.
 ==Stream Crossings==

@@ Line 18: / Line 18: @@
 =Discussion=
-Stream Crossings
+==Curved Horizontal Alignments==
-Box Culverts
+If possible, avoid locating bridges on curved horizontal alignments, since curved structures are more expensive to fabricate and are more difficult to construct than straight structures.  If a bridge falls within a curved roadway [[File:Curved_Roadway_Alignment_Ordinate.jpg|600px|right]] alignment, see if a tangent (straight) section can be introduced into the curve that encompasses the bridge limits.  If the curve radius is large enough, consider constructing the bridge with straight girders and deck and variable width shoulders.  To determine if this is feasible, determine the ordinate between the inside curve gutter line and the chord created by connecting the gutter line location at the bearing center line at each abutment.  If this value is less than 1 ft. 0 inches, the structure should be laid out with straight girders and deck.
-Pipe Culverts
+==Cross Slopes==
-Piers
+The preferred minimum cross slope on a bridge deck is 2 percent, which will facilitate travel lanes drainage and help avoid an icy bridge deck.  Constant cross slopes are preferred across the entire bridge length to reduce complex deck construction operations.  It is possible to accommodate transitional cross slopes in a bridge deck; however, the transition from normal crown (2 percent in each direction from the crown) to plane incline requires a longitudinal joint at the crown/pivot point and complicated camber in the girders to account for the unusual deflections that will occur.  It is also possible to have transitioning superelevation across a bridge, which would occur if it was in a reverse curve.  This should be avoided when possible, since it will result in a flat area on the deck when the superelevation is 0 percent, which does not facilitate the travel lanes water drainage and can lead to safety and maintenance issues.  If it is not possible to adjust the alignment so the bridge is not within the area of transitioning superelevation, scuppers should be placed on either side the flat area to capture bridge deck drainage before it reaches this point.
 |}
@@ Line 39: / Line 36: @@
 =See Also=
-[[Roadways: Culverts|Culverts]]
+*[[Roadways: Roadways:_Vertical_Alignment|Roadways: Vertical Alignments]]
 *[[Practical Design Implementation Guidance|Practical Design Implementation Guidance]]