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Bridging across unstable and variable ground with geosynthetic reinforced load transfer platforms

Features | December 23, 2025 | By: Daniel Alzamora, P.E.

Over the past 30 years the use of geosynthetic reinforced load transfer platforms (LTPs) has increased in various construction applications.

Photo courtesy of Tensar, a division of CMC.

These applications include the support of embankments over soft or variable foundation conditions as well as the support of large construction equipment, such as cranes. It also includes their use in combination with ground improvement elements which can transfer the loads through the soft unstable soils to more competent layers. The load transfer platform is typically composed of a granular fill and geosynthetic reinforcement layered in between. The goal of these technologies is to improve safety, performance, stability, cost and schedule. The overall thickness of the platform as well as the required reinforcement is designed around the strength and stiffness of the underlying soil conditions, the magnitude of the load being applied and the performance requirements of the system. 

Imagine a geosynthetic reinforced load transfer platform as a reinforced concrete beam.  The steel in the beam provides tension and confinement within the composite material. The combination of these two materials allows the beam to have a longer span with a thinner section. 

Similarly, the combination of the granular fill materials and geosynthetic reinforcements is generally designed as a composite mass where the geosynthetic provides the lateral and vertical confinement of the granular material creating the beam effect across soft spots. Soil arching is the fundamental process in effect, which can be more efficient when reinforcement is introduced.

Soil arching allows the soil to transfer load from soft or week spots to stronger areas. The result of this process when geosynthetics are introduced is typically a stronger and stiffer platform which can allow either an increase in load or the ability to reduce the thickness of the LTP while maintaining the required performance of the platform. The performance requirements are typically related to the load and the limitations for differential displacement at the top surface of the platform. 

The improved distribution of stress helps even out loads and deformations across variable site conditions. The use of LTPs can also help reduce or minimize lateral spreading of the fill. In addition, geosynthetic reinforcement can be designed to help address different loading conditions such as from large equipment where the loads can be concentrated at specific locations. The design of the LTP can accommodate these more complex loading conditions.

In cases where the foundation conditions are soft enough relative to the applied loads and required performance, the LTP can be used in combination with columns that are installed in a regular pattern under the embankment or structure.  A wide range of elements can be used for the columns, such as driven piles, drilled shafts, micro-piles or a variety of rigid inclusions. The objective of these elements would be to carry the load through the soft soil to a competent layer. This can be designed without the use of a LTP, but this is typically not done due to the recognized benefits of using a geosynthetic reinforced LTP. The LTP allows for more efficient configuration and spacing of these elements, which can significantly reduce construction schedule, complexity, and cost.  

As site development moves into areas which require more complex geotechnical solutions, the use of LTPs can provide the designer with a tool which can deliver a safer, faster, and economical project. As with all tools, this can work well in many cases, but it isn’t appropriate for all situations. The project engineers need to evaluate the suitability of any solution for the specific site conditions and design criteria. 

Additional information:

Daniel Alzamora, P.E., is a contributing editor for Geosynthetics and has spent more than three decades in the geosynthetics industry in both the public and private sector.

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