Use free draining stone for the fill. There are also methods to transfer the tensile force from the reinforcements behind the footings and allow your shallow foundation to be buried deeper.
Who designs stone "rubble" walls with geogrid anyways? The walls are inherently suited for gravity walls. A wet stacked, rigid retaining wall facing is not suited to the flexible characteristics of a reinforced retaining wall system. As Oldest said, do the gravity calcs and see if it works.
Long term design strength of the geogrid is based on test data provided by the manufacturer for different types of soils. If you feel confident you are utilizing the correct reduction factors, etc. for the backfill you are using, then ok. If you don't have test data to determine the LTDS of the...
The overall strength of the geogrid is based on the mobilization of the tension throughout the full length of the grid. Garrettk has a good point. If you reduce the ability of the grid to "deflect" slighlty within the soil, you will concentrate the resultant forces at the only place that will...
HDPE geogrids can be used with soils that have a ph range of 2-12 whereas PET is only good from 5-9. As for using soil cemented fill, you may want to investigate the interaction parameters between the reinforcement type you choose and the cemented soil. Check with the manufacturor for the...
If you are experiencing a geogrid overstress failure mode and not a connection failure, I agree with MSEMan. You can decrease the grid spacings to as little as 6" without causing a constructability problem. This is normal in geogrid structures over 50' tall. The additional grid will be far...
MSE walls are not typically designed for lateral loads other than earth pressures. As long as the vertical loads generated by the sign are transferred to a point below the bottom elevation of the reinforced soil zone, it should not impact the design of the wall. For instance,with a pressure...
The FHWA design manual deals with the design and construction of tiered walls. Tiered wall designs will more likely than not, result in the upper wall bearing directly on the reinforced zone of the lower wall. Something to keep in mind, internal and external stability calculations for the lower...
Thanks for the info. I am designing a small wall that will utilize a soil nail wall with a modular block facing at the bottom and will transition to a standard modular block wall reinforced with geogrid at the top to reduce the required excavation. The internal design is easily performed for...
Texas Tech has a research project called "Design procedures for MSE/Soil Nail Hybrid wall design". Can anyone help me locate this document or a similar one concerning the global stability analysis of this type of wall system. Design software is readily available to model the walls seperately but...
Drive guard rail posts, don't auger. Insert sleeves for fence posts during the wall construction. This makes things easy for the fence contractor. 4" pvc is adequate.
The critical factor in designing a segmental retaining wall that impounds water is rapid drawdown. Due to the fact you are designing a wall made from dry stacked concrete blocks, the water will obviously saturate the reinforced backfill during high water events. The FHWA design manual for MSE...
