Low Mobility Grout Rigid Inclusions (LMGRIs) are grout columns installed to transfer a foundation load to a competent soil or rock bearing stratum. LMGRI’s are constructed by drilling a grout pipe to the bearing stratum. The LMGRI Column is then constructed by withdrawing the grout pipe in intervals while injecting a known volume of grout to create a continuous column.
The LMGRI column is terminated within a few feet of the foundation. In some applications the LMGRI column may terminate in a competent stratum located beneath the foundation. In this instance, the LMGRI is transferring the load from a shallow competent stratum through a compressible stratum and ultimately taking up load in a deeper competent bearing stratum. Unlike deep piling systems, LMGRIs are not constructed into a pile cap. A Load Transfer Platform (LTP) system is designed and installed on top of the LMGRIs to transfer the load of the foundation.
Applications
- LMGRIs are used in soil profiles in variable soil profiles with compressible layers located between a competent surface layer and a bearing stratum
- Low to mid rise new construction buildings
- Area loads such as tanks and embankments
Construction Advantages
- Economical compared to deep foundations and does not require pile chipping, cut-off or cap
- Increased allowable soil bearing capacity reduces the size of foundations
- Expedient process
- In the Tampa Bay area, Earth Tech can provide and deliver grout from its ready-mix plant to maintain project schedule
- Outside of the Tampa Bay area, Earth Tech can supplement third party grout deliveries with its own ready-mix trucks to maintain project schedule
What to expect
- Earth Tech will provide a signed and sealed design indicating treatment plan and if needed Load transfer platform details.
- Site clearing and access preparation precede LMGRI
- Site access for ready- mix trucks is needed.
- Drilling spoils may accumulate on the surface and must be disposed of
- Typically, this work is performed under a performance specification, with criteria specified regarding bearing capacity and settlement
- Load testing can be used to verify design criteria
- A load transfer platform may be needed and is typically constructed by others.
- Final site grading, spoil clean up and foundation construction follow the LMGRI’s.
