Roadways: Design Storm - Revision history

Mnemphos at 17:12, 11 December 2024

2024-12-11T17:12:58Z

Mnemphos at 13:00, 6 June 2024

2024-06-06T13:00:44Z

Mnemphos: /* Scour */

2016-11-09T14:47:30Z

‎Scour

Mnemphos at 14:47, 9 November 2016

2016-11-09T14:47:05Z

Mnemphos at 19:04, 3 November 2016

2016-11-03T19:04:56Z

Mnemphos at 19:04, 3 November 2016

2016-11-03T19:04:47Z

Mnemphos: /* See Also */

2016-11-03T19:04:34Z

‎See Also

Mnemphos: /* Primary Guidance */

2016-11-03T19:04:00Z

‎Primary Guidance

Mnemphos: /* Discussion */

2016-11-03T19:03:40Z

‎Discussion

Mnemphos at 19:02, 3 November 2016

2016-11-03T19:02:06Z

← Older revision		Revision as of 17:12, 11 December 2024
Line 47:		Line 47:
	*[[Roadways: Shoulder Width\|Shoulder Width]]		*[[Roadways: Shoulder Width\|Shoulder Width]]
	*[[Practical Design Implementation Guidance\|Practical Design Implementation Guidance]]		*[[Practical Design Implementation Guidance\|Practical Design Implementation Guidance]]
−	~~[[Category:Secure]]~~

← Older revision		Revision as of 13:00, 6 June 2024
Line 47:		Line 47:
	*[[Roadways: Shoulder Width\|Shoulder Width]]		*[[Roadways: Shoulder Width\|Shoulder Width]]
	*[[Practical Design Implementation Guidance\|Practical Design Implementation Guidance]]		*[[Practical Design Implementation Guidance\|Practical Design Implementation Guidance]]
		+	[[Category:Secure]]

← Older revision		Revision as of 14:47, 9 November 2016
Line 39:		Line 39:

	==Scour==		==Scour==
−	A scour evaluation or assessment must be performed and approved for any bridge or bottomless culvert over a waterway that is to be rehabilitated or replaced with federal or State funds. Structures with paved bottoms (pipes, pipe arches, box culverts, etc.) do not require a scour evaluation. A scour evaluation is a detailed scour study to estimate scour depths at substructure foundations, and a scour assessment consists of a field and office review of plans and records to determine the degree of risk of scour damage. If the scour damage risk is low, no further study is needed. If the risk is high, detailed scour evaluations or additional studies are needed. Action is needed to address and minimize the potential for scour damage and resulting risk to the public. Scour evaluations should be performed for the 100 year storm regardless of the roadway functional classification. This is to ensure that the bridge will not wash out in a major storm event, which can lead to a loss of life. The resulting cost increase to the substructure foundations are significantly lower than the cost of replacing an entire bridge.	+	A [http://www.gishydro.eng.umd.edu/sha_april2016/Ch11_160406.pdf scour evaluation or assessment] must be performed and approved for any bridge or bottomless culvert over a waterway that is to be rehabilitated or replaced with federal or State funds. Structures with paved bottoms (pipes, pipe arches, box culverts, etc.) do not require a scour evaluation. A scour evaluation is a detailed scour study to estimate scour depths at substructure foundations, and a scour assessment consists of a field and office review of plans and records to determine the degree of risk of scour damage. If the scour damage risk is low, no further study is needed. If the risk is high, detailed scour evaluations or additional studies are needed. Action is needed to address and minimize the potential for scour damage and resulting risk to the public. Scour evaluations should be performed for the 100 year storm regardless of the roadway functional classification. This is to ensure that the bridge will not wash out in a major storm event, which can lead to a loss of life. The resulting cost increase to the substructure foundations are significantly lower than the cost of replacing an entire bridge.

@@ Line 7: / Line 7: @@
 | colspan="3" |
 =Primary Guidance=
-*Provide a minimum bridge clear roadway width so the bridge is not classified as Functionally Obsolete
+*Size bridges and culverts to safely pass the design year storm without overtopping as based upon the roadway functional classification  and risk assessment
-*Bridge lane and [[Roadways: Shoulder Width|Shoulder Widths]] should match the approach roadway lane and shoulder widths unless it results in a Functionally Obsolete bridge
+*A [http://www.gishydro.eng.umd.edu/sha_april2016/Ch11_160406.pdf scour evaluation] is required for bridges and bottomless culverts over a waterway
-*Provide sufficient bridge width to safely address bicycle and pedestrian requirements
+*See Bridge – Stream Crossing  for bridges and large culverts
-*Accommodate the needs of future capacity improvements that will occur within 20 years.
+*See Drainage/Hydraulics – Culverts  for small culverts
 |-
 | colspan="3" |

@@ Line 8: / Line 8: @@
 =Primary Guidance=
 *Provide a minimum bridge clear roadway width so the bridge is not classified as Functionally Obsolete
-*Bridge lane and *[[Roadways: Shoulder Width|Shoulder Widths]] should match the approach roadway lane and shoulder widths unless it results in a Functionally Obsolete bridge
+*Bridge lane and [[Roadways: Shoulder Width|Shoulder Widths]] should match the approach roadway lane and shoulder widths unless it results in a Functionally Obsolete bridge
 *Provide sufficient bridge width to safely address bicycle and pedestrian requirements
 *Accommodate the needs of future capacity improvements that will occur within 20 years.

← Older revision		Revision as of 19:04, 3 November 2016
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	=See Also=		=See Also=
		+	*[[Roadways: Shoulder Width\|Shoulder Width]]
	*[[Practical Design Implementation Guidance\|Practical Design Implementation Guidance]]		*[[Practical Design Implementation Guidance\|Practical Design Implementation Guidance]]

@@ Line 39: / Line 39: @@
 At a minimum, size structures to preclude overtopping by the design storm for the roadway classification. Design exceptions may be granted on a case-by-case basis in instances where overtopping is considered low-risk, when there is no history of overtopping, or when based on value-engineering.  Site conditions, such as existing development, may also constrain solutions that do not meet the design storm, resulting in in-kind replacements.
-In addition, H/H analysis  must comply with COMAR 26.17.04  regarding impacts to floodplains.  Water surface increases must be limited to 0.1 ft. on improved properties; up to 1.0 ft. on unimproved properties with property owner notification and/or concurrence and mitigation.  If the structure is within a FEMA floodplain, the water surface increase must be kept to 0.00 ft.
+In addition, hydrology and hydraulic  analyses  must comply with COMAR 26.17.04  regarding impacts to floodplains.  Water surface increases must be limited to 0.1 ft. on improved properties; up to 1.0 ft. on unimproved properties with property owner notification and/or concurrence and mitigation.  If the structure is within a FEMA floodplain, the water surface increase must be kept to 0.00 ft.
 ==Scour==

@@ Line 22: / Line 22: @@
 {| class="wikitable"
-AASHTO Classification	Flood Frequency Storm
+! AASHTO Classification
-*Interstate, other Freeways and Expressways and Principal Arterials	100 year
+! Design Storm Frequency
-*Intermediate and Minor Arterials	50 year
+|-
-*Collectors	25 year
+| Interstate,other Freeways, and Expressways and Principal Arterials
-*Local Roads	10 year
+| 100 Year
 |}
 At a minimum, size structures to preclude overtopping by the design storm for the roadway classification. Design exceptions may be granted on a case-by-case basis in instances where overtopping is considered low-risk, when there is no history of overtopping, or when based on value-engineering.  Site conditions, such as existing development, may also constrain solutions that do not meet the design storm, resulting in in-kind replacements.