Ground-mounted metal structures for PV plants for different soils

The role of ground-mounted metal structures in PV projects in Uzbekistan

For large ground-mounted solar power plants in Uzbekistan, choosing the right structural solution for a specific soil type is one of the key factors for the reliability and economics of the project. An error at this stage leads to excess steel consumption, installation issues, and risks to commissioning deadlines.

Ground-mounted metal structures for solar panels are not just mounting rails and posts. They are a comprehensive solution:

• support system (piles, posts, anchors);
• load-bearing frame (trusses, beams, columns);
• fasteners for solar panels (profiles, clamps, hold-downs);
• connecting elements and adjustment nodes.

For PV developers, EPC contractors, and design institutes, it is important to understand how soil type affects the structural solution, steel volume, installation technology, and ultimately CAPEX.

BRIX.UZ performs calculations according to the technical specification and manufactures metal structures for solar power plants in Tashkent, taking into account the actual soil conditions of the site.

What initial soil data are needed for structural calculations

Accurate calculation of ground-mounted metal structures is impossible without geotechnical data. To select a structural solution for a PV plant, it is desirable to have:

• Geotechnical investigations for the site (boreholes, laboratory tests);
• soil type by layers (loam, clay, sand, gravel, rock inclusions, etc.);
• frost depth and groundwater level;
• design soil resistance to compression and pull-out;
• presence of collapsible, swelling, saline soils;
• topography (slopes, need for terracing);
• wind and snow loads for the region.

If full geotechnical investigations are not available, a preliminary calculation is possible using generalized data and regional experience, but for large PV plants this is always a compromise. In any case, the technical specification should at least fix:

• the assumed soil type;
• the design embedment depth of supports;
• requirements for the service life of the structure;
• restrictions on equipment at the site (whether a pile driver, drilling rig, etc. can be brought in).

Main types of ground-mounted structures for PV plants and their application

By the way they interact with the soil, ground-mounted structures for solar power plants are conventionally divided into:

1. Driven systems

   • posts made of channel, I-beam, or hollow section driven into the ground;
   • used on dense load-bearing soils without large boulders.

2. Screw piles

   • steel piles with blades screwed into the ground;
   • suitable for loose, weak, and water-saturated soils.

3. Bored cast-in-place / injection solutions

   • drilling boreholes followed by concreting and installation of embedded parts;
   • used for difficult soils and high loads.

4. Anchored and ballasted systems

   • fastening to monolithic or precast concrete blocks;
   • applicable where the soil must not be disturbed (leased sites, technical restrictions).

5. Combined schemes

   • combination of driven/screw supports with local concreting of nodes;
   • relevant for areas with heterogeneous soils.

Below we consider which structures are rational for different soil types, taking into account conditions in Uzbekistan.

Solutions for dense and rocky soils: driven and anchored systems

Dense load-bearing soils (loams, sandy loams, dense sands)

For most sites in the region where soils have sufficient bearing capacity, driven metal structures are optimal:

• posts made of hot-rolled sections or reinforced hollow sections;
• driving to the design depth with refusal control;
• upper part – trusses or beams for PV module mounting rails.

Advantages:

• high installation speed (if pile-driving equipment is available);
• no wet processes and concrete curing time;
• minimal earthworks.

Structural features:

• increased post section for high wind loads;
• reinforcement of truss and mounting rail connection nodes;
• consideration of corrosion resistance (galvanizing or coating systems).

Rocky and semi-rocky soils

On sites with outcrops of rock or boulders, pile driving may be difficult or economically impractical. In this case, the following are used:

• anchored systems – drilling anchors into the rock and fastening steel posts;
• support frames on chemical anchors in pre-drilled holes.

The structural solution differs by:

• presence of base plates or shoes under the posts;
• reinforced anchor connection nodes;
• possible transition from single posts to frame structures to redistribute loads.

Solutions for loose and weak soils: screw piles and combined schemes

Loose sands, fill, and weak soils

On sites with low design soil resistance, it is rational to use screw piles or combined solutions:

• piles with one or several blades to increase bearing capacity;
• installation with control of torque and depth;
• upper head part – flange or profile for welding the post.

Advantages of screw piles:

• possibility of installation without concreting;
• work in both compression and pull-out (relevant for high wind loads);
• suitability for water-saturated and seasonally waterlogged soils.

Structural features:

• increased shaft and blade diameter for weak soils;
• reinforcement of the "pile–post" connection (flanged joints, welded nodes);
• corrosion protection along the entire length of the pile, not only in the above-ground part.

Combined solutions

With heterogeneous soils across the site (patches of weak soils, local settlements), mixed schemes are possible:

• driven posts on most of the field;
• screw piles or bored cast-in-place supports in problematic zones;
• unified upper structure (identical trusses, mounting rails, and fasteners for solar panels).

This approach helps keep the budget and schedule under control without complicating installation across the entire PV field.

Structural features on swelling, collapsible, and saline soils

Swelling and collapsible soils

For sites with swelling clays or collapsible loess, it is important to:

• avoid shallow embedment of supports in the active deformation zone;
• use bored cast-in-place piles with embedment below the problematic layer;
• provide rigid bracing between posts (diagonals, row bracing).

The structural solution may include:

• steel posts anchored in concrete column foundations;
• frame systems instead of single posts to redistribute settlements;
• height adjustment nodes to compensate for possible differential deformations.

Saline and aggressive soils

In conditions of increased soil corrosivity (saline soils, industrial sites):

• the risk of corrosion of the underground part of supports increases;
• standard protection may be insufficient for the project service life.

Solutions:

• hot-dip galvanizing of the entire structure, including the underground part;
• increased steel thickness in the soil/air interface zone;
• use of additional protective coatings or sleeves in the most aggressive zone.

In the technical specification for calculation, it is important to explicitly indicate:

• the assumed environmental aggressiveness;
• the required service life of the system without major overhaul.

Materials and technologies: carbon steel, galvanizing, stainless steel, powder coating

Material selection

For ground-mounted metal structures of PV plants, the following are used in most cases:

• carbon steel with subsequent protection (hot-dip galvanizing, paint coatings);
• stainless steel – selectively, in nodes with increased corrosion resistance requirements (fasteners, individual elements of food or chemically loaded equipment on the PV site).

Fully stainless steel frames for PV fields are rarely used due to cost, but stainless steel is relevant for auxiliary food-processing equipment, tables, sinks, and racks at facilities combining energy and food-processing infrastructure.

Processing technologies

The same technological operations are used for manufacturing PV structures as for other metal structures:

• laser cutting – precise fabrication of plates, fasteners, mounting holes;
• metal bending – forming profiles, brackets, mounting rail elements;
• welding – assembly of trusses, posts, connection nodes;
• powder coating – additional protection of the above-ground part (especially in areas with high insolation and dust load);
• hot-dip galvanizing – main corrosion protection for above-ground and underground parts.

When ordering, it is important to fix in the technical specification:

• the required type of protective coating;
• application zone (above-ground/underground part);
• appearance requirements (usually minimal for industrial PV plants, higher for commercial facilities).

What affects the cost of frames and fasteners for solar panels

The cost of ground-mounted metal structures for PV plants is formed by a combination of factors. Below is a generalized comparison.

The specific price is calculated individually based on the technical specification. Without initial data on soils, loads, and field layout, the estimate will be approximate.

Typical mistakes when selecting and ordering ground-mounted metal structures for PV plants

1. Lack or neglect of geotechnical data

   • A standard structural solution is used that does not account for weak or collapsible soils.
   • Result – excess steel consumption or stability issues.

2. Choosing the structural solution based only on steel price

   • Installation cost, equipment, and schedule are not considered.
   • A cheap steel option may turn out more expensive in the full EPC budget.

3. Underestimation of wind loads

   • Especially relevant for open sites in Uzbekistan.
   • The error leads to increased deformations and risk of panel damage.

4. Lack of unification of nodes and sizes

   • Too many unique parts complicate production and supply.
   • Lead times and risks during additional deliveries increase.

5. Poorly developed height and slope adjustment scheme

   • On sloping sites it is harder to maintain field flatness.
   • Additional on-site works arise that were not included in the budget.

6. Failure to account for soil and atmospheric corrosivity

   • Minimal protection is specified that does not match the project service life.
   • Unscheduled repairs are required after a few years.

7. Gap between design and production

   • Design documentation is not adapted to real technologies (laser cutting, bending, welding).
   • On-site modifications appear, deadlines shift, and costs grow.

BRIX.UZ production capabilities for PV projects

BRIX.UZ in Tashkent offers a comprehensive approach to ground-mounted metal structures for solar power plants:

• calculation according to the technical specification taking into account soil type, loads, and field layout;
• contract manufacturing of metal structures according to your design documentation or with adaptation to our technology;
• laser cutting and metal bending for precise fasteners and mounting rails;
• welding of trusses, posts, frame structures;
• powder coating and work with galvanized steel;
• preparation for serial production of elements for large PV plants.

We can adapt the structural solution to:

• driven, screw, bored, and ballasted foundations;
• different solar panel sizes and layout schemes;
• phased construction with split deliveries by stages.

Lead times depend on volume, structural complexity, and production load. A basic schedule estimate can be provided already at the preliminary technical specification stage.

FAQ on ground-mounted metal structures for solar power plants

1. Can the same type of frame be used on different soils?
Partially – yes, if only the type of supports is changed (driven, screw, bored), while keeping a unified upper structure (trusses, mounting rails, fasteners for solar panels). But the final decision is made based on calculation results.

2. What if geotechnical investigations are not yet available, but a budgetary offer is needed?
A preliminary calculation can be done using typical soils of the region and wind region data. The commercial offer will state that the final calculation and bill of materials will be adjusted after geotechnical data are obtained.

3. Which material is better for the frame – coated carbon steel or stainless steel?
For PV fields in Uzbekistan, carbon steel with high-quality protection (hot-dip galvanizing, and powder coating if necessary) is usually the most rational. Stainless steel is used selectively where it is truly justified.

4. Can different types of supports be combined within one PV field?
Yes, this is standard practice for heterogeneous soils. It is important to plan this in the design stage and unify the upper structure to avoid complicating production and logistics.

5. How to account for terrain slopes when designing the frame?
Either height adjustment nodes on posts are used, or the site is terraced. The choice depends on slopes, budget, and requirements for precise sun tracking.

6. What panel data are needed to calculate metal structures?
Module dimensions and weight, mounting scheme (portrait/landscape), number of modules per string and per row, frame type, and permissible mounting points. These parameters directly affect spans and member sections.

7. Is it possible to order only manufacturing based on finished drawings?
Yes, BRIX.UZ manufactures to order based on provided design documentation. If necessary, we can propose optimization of the structural solution for our technologies (laser cutting, metal bending, welding) without changing the design scheme.

8. Do you perform installation of ground-mounted structures for PV plants?
The possibility of installation works is discussed separately and depends on the project location, volume, and construction schedule. In any case, the structural solution is developed with installation convenience and speed in mind.

How to request a calculation: what data to prepare and what lead times to expect

To obtain a technically sound calculation and commercial offer for ground-mounted metal structures for a solar power plant, prepare a technical specification with the maximum set of initial data.

Minimum data set for calculation:

• region and approximate location of the PV site;
• geotechnical results (if available) or soil description;
• wind and snow region (or simply the project location);
• field layout: number of rows, row length, row spacing;
• solar module type (dimensions, weight, portrait/landscape);
• required tilt angle and height of the lower panel edge;
• assumed support type (if already selected: driven, screw, bored, ballasted);
• required service life of the structure;
• approximate delivery schedule and batch volumes.

Additionally, it is desirable to specify:

• restrictions on equipment at the site (access for heavy machinery, power supply availability);
• coating requirements (galvanizing, powder coating, combined options);
• whether turnkey installation is needed or only supply of metal structures and fasteners for solar panels.

After receiving the technical specification, BRIX.UZ:

• performs a preliminary calculation and selects a structural solution for your soils and loads;
• prepares a bill of main elements (posts, trusses, mounting rails, fasteners);
• provides indicative manufacturing and delivery times.

Submitting a calculation request

The most convenient way is to send the technical specification and initial data via the website form or by email. In the request, specify:

• company name and contact person;
• phone and email for communication;
• region and brief project description (PV plant capacity, approximate area);
• availability/lack of geotechnical investigations for the site;
• main requirements for the structural solution and coating;
• desired date for receiving the commercial offer.

Based on this data, we will prepare a calculation and propose an option for ground-mounted metal structures for your solar power plant that is optimal in terms of technology and schedule.