RE: Rip-rap slopes 1

[bmoc]

For a marina project, we have boat slips with 8" to 12" rip-rap on the land side (end of slip). Currently, the rip-rap slope is 1:2. Can we make steeper, say 1:1-1/2, or even 1:1?

 

[cvg]

It's generally not recommended for loose riprap to go over 2:1

 

[BigH]

Please gentlemen - to reduce confusion put in the H and V. Structural engineers and some civils use V:H and geotechs use H:V. And, many times countries differ as well. Makes things easier-e.g., 2H:1V. Thanks.

 

[wds1]

When I worked for a D.O.T. in a mountainous state we sometimes went as steep as 1.5H:1V. If you ever hiked in the mountains you may see areas where natural piled rocks approach a 1H:1V slope. They are somewhat unstable. If you climb on them, many will roll down hill. It's probably best to stick to 2:1, unless you investigate it further.

 

[GeoPaveTraffic]

I would say if you go steeper than 2H:1V, you should plan on hand placement of the stones. If you do hand placement you can go to 1:1 or steeper if the stones are large, but then you are actually building a wall.

 

[namdac]

If you wish to go to a 1:1 slope or steeper there are a ton of other options.
1.)Do you have funds to use other materials?
2.)If so, pour a sea wall and use the riprap as a bank stabilizer.
3.)Use Gabions, You can stack Gabions to what ever slope you desire.
4.)Drive sheet pile.
5.)Where I fish we have used interlocking retaining wall stones.

It depends on what your objective is and how much money you want to throw at it.

Regards,
Namdac

 

[smwpe]

bmoc

where are you? It makes a difference.

 

[bmoc]

Project is in Bay City, Michigan. I went with 2H:1V MDOT heavy rip-rap slopes. Seawall was too expensive.

 

[RCEJD]

A good reference for this issue is the Caltrans (State of California) Shore Protection manual that you can download on-line.

Although as many posts have noted, 2:1 has become the standard for ungrouted rip-rap, we have had several projects where environmental agencies have conditioned no grouting, and economics have prevented walls. Select placement of the stones to decrease the voids and create effective point-to point contacts will allow steeper slopes. But a larger skeleton size (i.e larger stones), within intermediate filler sizes will be required, with good field control.