frp bridge drain pipe
TRANSCRIPT
FRP Bridge Drain Pipe Systems
Basic Design Characteristics for
Successful Installations
Points of Concern
• Expansion and Contraction
Free Floating Connection
Bridges are dynamic structures where slight shifts and vibrations are expected. The dynamic forces of both the bridge and drainage system don’t always agree. Leaving a free floating connection between deck outlets and
the subsequent pipe is one way to account for these anticipated movements.
Expansion JointsFor Approximately 200’ of Horizontal Pipe 1 Expansion Joint is Required
The Thermal Expansion Coefficient Value for FRP is 0.000014 in/in/FSo the Typical Expansion Formula isΔL (in) = L (in) x ΔT (F) x 0.000014
Anticipated Expansion of Pipe @ ΔT=100° & L=2400” ==> ΔL=3.36”
The Total Length of Movement for the Expansion Joint Fitting in Most Pipe
Diameters is Approximately 7”
Points of Concern
• Expansion and Contraction
• System Slope
Slope Requirement of >2%
It is essential for conveyance systems being installed to meet these minimum slope requirements. While fiberglass pipe does have an excellent Hazen-Williams coefficient of 150, without the proper slope, systems will become more likely to collect debris and clog.
Slope in Respect to AngleSlope (%) = (Rise/Run) * 100
Angle = Arctan(Rise/Run)
Example: Slope = 2%
(Rise/Run) = .02 unit/unit
Angle = Arctan(.02) = 1.15°
Example: Slope = 3.5%
(Rise/Run) = .035 unit/unit
Angle = Arctan(.035) = 2°
Custom Fittings to Match Any Slope You May Need
Points of Concern
• Expansion and Contraction
• System Slope
• Clean Outs
Clean Out Considerations
By placing clean out plugs at the end of long runs of pipe
maintenance crews will have the ability to service any
potential system clogs. With clean outs its not always the
quantity that matters. Strategic placement of the
clean outs is just as important. By placing a clean out in a hard to reach area
crews may not have the required access to preform
the needed work.
Points of Concern
• Expansion and Contraction
• System Slope
• Clean Outs• Horizontal Curves
Horizontal Curve PerformanceOur Product Exceeds a Stiffness Factor value of 200 in^3·lbf/in^2 @ 5% Deflection
This Means that Approximately 1’ of Deflection is Allowed Per 21’ Run of Pipe
If 1’ Deflection is Insufficient, Small Angled Elbows in the Range of 1°- 5°can be Added to Match the Horizontal Curves
Points of Concern
• Expansion and Contraction
• System Slope
• Clean Outs• Horizontal Curves
• System Outlets
System Outlets
A bent system outlet and a high class riprap will help minimize erosion at the base of the structure
Points of Concern
• Expansion and Contraction
• System Slope
• Clean Outs• Horizontal Curves
• System Outlets
• Hanger System
System SupportsDesign Engineers Should Locate Pipe Supports Near
Directional Changes and Socket Connections to Ensure All Joints Will Stay Secure Throughout the Systems Lifecycle
For Most Pipe Diameters Be Sure to Include a Hanger at Least Once Every 20 Feet of Horizontal Pipe That Runs
Parallel With the Bridge Deck
Recommended Maximum Support Spacing
Pipe Size (in.)
Support Spacing
(ft.)
Minimum Support
Width (in.)
Hanger Load Pipe Only (lbs.)
Hanger Load Pipe & Water
(lbs.)
4 16.5 1 ¼ 21.5 145
6 18.3 1 ½ 36.6 288
8 20.2 1 ¾ 52.6 518
10 21.3 1 ¾ 70.3 829
12 22.4 2 87.4 1221
14 23.2 2 104.1 1708
16 24.0 2 ½ 124.8 2268
18 24.8 3 143.9 2932
20 25.7 3 ¾ 218.5 3634
24 26.7 4 ½ 272.4 5586
Do you have specific questions about the system you are currently designing that we did not already answer?
Please give us a call and we would be more than happy to further discuss your unique situation and help find a solution!
Call Nathan Peters at (636) 938-6313