
Naue UnpavedRoad – modified GH
Smarter temporary access and haul roads
Naue UnpavedRoad – modified GH is a free online calculator in the Naue Portal DesignSuite for designing unpaved roads: temporary access roads, haul roads and working areas. It determines the required thickness of the unbound base course project-specifically, using the proven modified Giroud & Han method (2004), taking account of the subgrade bearing capacity, the expected traffic loading and the permissible surface deformation (rut depth). By building in the measured performance of Secugrid® geogrids and Combigrid® geocomposites, the tool shows how much the unbound base course can be reduced, cutting material, cost, and construction time while keeping the road stable and durable, even over soft subsoils.
At a glance
- What it is: a free online calculator in the Naue Portal DesignSuite (login required)
- What it does: assists with the design of the unbound base course of unpaved roads to the modified Giroud & Han method
- Best for: temporary access roads, haul roads and working areas - including sites over soft subsoils
- Key inputs: vehicle type; axle load F (kN); wheel width D (cm); permissible rut depth (mm); number of passes N; lane-tracking effect; subgrade (CBR or Ev2/modulus); base-course material; Secugrid®/Combigrid® reinforcement
- Key outputs: required unbound base-course thickness with and without geogrid; thickness reduction; cost savings versus conventional; downloadable report
- Method: Modified Giroud & Han (2004), with wheel-wandering (lane-tracking) simulation
From traffic and subgrade data to a leaner base course: how UnpavedRoad delivers
Challenges
- Building stable temporary roads over weak or soft subsoils
- Thick base courses drive material, haulage cost and time
- Proving the savings from geogrid stabilisation
Naue solution
- A modified Giroud & Han calculator that includes the stabilisation, reinforcement and separation effect of Secugrid® and Combigrid® geogrid solutions
Results
- The required base-course thickness for your rut and traffic limits
- A reduced base course with geogrid, at equal performance
- Quantified cost savings versus conventional, with a downloadable report
Where UnpavedRoad – modified GH helps: applications covered
Naue UnpavedRoad – modified GH is used wherever a stable, cost-effective unpaved road or working area is needed, especially on weak subsoils where geogrid stabilisation delivers the greatest savings.
- Temporary access roads: stable, cost-effective access for construction and industrial sites.
- Haul roads: durable routes for heavy construction and site traffic.
- Working areas and platforms: load-bearing surfaces for plant, laydown and staging areas.
- Soft subsoil sites: geogrid stabilisation where subgrade bearing capacity is low.
- Wind energy access: stable platforms and access roads for onshore wind projects.
How UnpavedRoad – modified GH works: input, geogrid benefit and savings
A guided form collects the road, traffic and ground data and returns the required base-course thickness. It incorporates the geogrid benefit and the cost saving made explicit, and the option to save the calculation to a project.

Enter your road, traffic and ground data
Define the load, the performance requirement and the ground. UnpavedRoad then determines the required unbound base-course thickness so the road meets your rut-depth and traffic limits.
Practical advantages:
- Load input: vehicle type, axle load (kN) and wheel width (cm); tyre contact pressure is derived automatically
- Requirements: permissible rut depth (mm) and number of axle passes, with an optional lane-tracking (wheel-wandering) effect
- Subgrade defined by CBR or Ev2 / elasticity modulus, with a selectable subgrade type
- Base-course material and its stiffness, plus selection of the Secugrid®/Combigrid® reinforcement
- Mobile and desktop access for on-the-go planning

The geogrid benefit: less aggregate, same stability
UnpavedRoad integrates the latest research on geosynthetics with the measured performance of Naue products. Secugrid® and Combigrid® contribute a combined stabilisation, reinforcement and separation effect that lets the unbound base course be reduced at equal performance:
- Reduced base-course thickness means less aggregate to place and haul, and faster construction
- Reliable stability and longer road life, even on soft subsoils
- Wheel-wandering simulation spreads wheel loads laterally across the road width, reducing stress on weak subgrades

Cost savings, report and DesignSuite integration
UnpavedRoad quantifies, documents and connects the result:
- Calculates the total saving versus a conventional solution without geosynthetics, based on the stabilisation, reinforcement and separation effect of the Secugrid® and Combigrid® range
- Download a report of the design and savings; save the calculation to a project in the Naue Portal
- Convert various vehicle configurations into ESALs with the Naue AxleLoad tool for precise traffic input
- Use it alongside other DesignSuite calculators such as PavedRoad – AASHTO and SecuCalc; direct links to the Naue Engineering & Design team

Benefits for every project stakeholder
For planners and design engineers
Accurate base-course design by the modified Giroud & Han method, with verified geogrid performance and a clear basis. The Naue engineering team provides project-specific review and support.
For contractors and site managers
Thinner base courses mean less aggregate to place and haul and faster construction of reliable roads even on soft ground, planned from any device.
For project owners and clients
Lower material and construction costs with quantified savings versus conventional for efficient, resilient temporary infrastructure.
UnpavedRoad – modified GH: method, standards and engineering support
| Method / framework | Scope |
|---|---|
| Modified Giroud & Han (2004) | Design of the unbound base-course thickness for unpaved roads |
| Rut-depth criterion | Permissible surface deformation of the base course governs the design |
| Geosynthetic stabilisation | Stabilisation, reinforcement and separation effect of Secugrid® and Combigrid® built into the design |
| Naue EDD | Project-specific review, verification and design support |
| UnpavedRoad is based on the modified Giroud & Han method for unpaved roads, combined with the measured performance of Naue geogrids. Where a project needs individual review, the Naue Engineering and Design Department (EDD) supports planners and contractors with project-specific design. |
The UnpavedRoad advantage: build temporary roads smarter
Naue UnpavedRoad – modified GH lets engineers build temporary roads cleverly, save money and improve efficiency, and create robust, stable solutions even on soft subsoils. By optimising the unbound base-course thickness with Secugrid® and Combigrid®, it reduces material and construction costs and time, and quantifies the saving against conventional designs - all from a fast, intuitive tool accessible on web and desktop, backed by Naue's engineering support.
Naue UnpavedRoad – modified GH: frequently asked questions
Naue UnpavedRoad – modified GH is a free online calculator in the Naue Portal DesignSuite. It helps to design the unbound base course of unpaved roads like temporary access roads, haul roads and working areas, using the modified Giroud & Han method and the performance of Secugrid® geogrids and Combigrid® geocomposites.
It is based on the proven Giroud & Han approach (2004), refined ('modified') to incorporate the advanced performance properties of Naue Secugrid® geogrids and Combigrid® geocomposites for a more efficient and reliable design.
For temporary and unpaved roads: construction and industrial access roads, haul roads, working platforms and staging areas - particularly where the subgrade is weak or soft.
The load (vehicle type, axle load and wheel width), the requirements (permissible rut depth and number of passes, with an optional lane-tracking effect), the subgrade (type and CBR or Ev2/modulus), the base-course material, and the Secugrid®/Combigrid® reinforcement.
They provide a combined stabilisation, reinforcement, separation, and filtration effect. Based on verified product performance, the tool reduces the required unbound base-course thickness at equal performance, cutting aggregate use and cost.
Yes. An optional wheel-wandering (lane-tracking) simulation spreads wheel loads laterally across the road width, reducing stress on weak subsoils. Vehicle configurations can be converted into ESALs using the Naue AxleLoad tool.
It calculates the total saving compared with a conventional solution without geosynthetics, produces a downloadable report, and lets you save the calculation to a project in the Naue Portal.
It is free within the Naue Portal and requires a portal login, with mobile and desktop access. You can register here. The software tools are aimed at design engineers, planners, contractors and project owners.