Bolted Silo
Specifications
[EPC Project Display] Assembly Silos in Concrete Batching Plants / Concerte Production Line
1
Basic Dimensions & Forming Parameters
Built for industrial bulk storage, Neorigin bolted steel silos provide enhanced structural strength, corrosion protection, and sealing. Prefabricated panel silos are built to last and designed to accommodate grain, cement, chemicals, and mining, ensure durability and operational efficiency.
| Parameter | Specification/Range |
|---|---|
| Silo Body Plate Thickness | 1.5 – 14.0mm (5-8mm for diameter >15m; 10mm+ for heavy-duty storage) |
| Steel Strength | 550MPa High-strength Galvanized Steel (Q345 / NM450 Wear-resistant Steel) |
| Bolt Connection Specification | M12-M20 High-strength Anti-corrosion Bolts, Overlap Width ≥30mm, Double-layer Sealant Filling |
| Anti-corrosion System | 100μm Epoxy Zinc-rich Primer + 150μm Polyurethane Topcoat, Hot-dip Galvanized Substrate ≥275g/m² |
| Reinforcing Rib Specification | Channel Steel / Corrugated Reinforcing Ribs, Spacing 800-1200mm; Additional Circumferential Reinforcing Rings for Tall Silos |
| Sealing Performance | Plate Lap Sealing, IP65 Dustproof & Waterproof Rating, Zero Leakage in Air Tightness Test |
Technical Highlights
- Customizable Wall Thickness: Plate standard thickness from 1.5–14.0mm. For silos with diameters over 15m, suggest plates with thicknesses of 5–8mm. For heavy duty storage, suggest 10mm+ thickness.
- High-Strength & Corrosion Resistance: Built from 550MPa galvanized steel (Q345/NM450 optional) with a 3 layer anti-corrosion (≥275g/m² + 100μm primer + 150μm topcoat).
- Robust Reinforcement & Sealing: Channel ribs spaced 800-1200mm and additional rings for tall silos, along with M12–M20 bolted joints and two layers of sealant for IP65.
2
Material & Structural Specifications
Depending on storage contents, the environmental humidity, and project lifespan, various grades of steel, and systems of anti-corrosion can be selected.
| Parameter | Specification Range | Description |
|---|---|---|
| Silo Type | Corrugated Bolted / Flat Panel Bolted | Selected based on storage capacity and application |
| Steel Grade | Q235 / Q355 / S350GD / SS400 | Determined by structural load and wind/seismic conditions |
| Plate Thickness | 1.5 – 14.0 mm | Varies by silo diameter and wall pressure |
| Zinc Coating | Z275 / Z450 / Z600 | Selected according to humidity and corrosion level |
| Bolt Grade | 8.8 / 10.9 Hot-Dip Galvanized | Ensures structural reliability and long-term stability |
| Sealing System | EPDM / PU Sealant / Double Sealing | Prevents moisture ingress and air leakage |
| Roof Structure | Cone Roof / Truss Roof / Flat Roof | Configured according to snow load and ventilation needs |
| Wind Resistance | Up to 130 km/h | Engineered according to local wind load requirements |
| Seismic Design | Up to Zone 9 | Optional seismic reinforcement design |
| Corrosion Protection | HDG + Epoxy / PU / Fluorocarbon | Optional multi-layer protection systems |
Technical Highlights
- Customize Silo Type & Steel Grade for Your Application: For storage of bulky materials, select corrugated bolted silos of steel grade Q355B/S350GD instead of the standard grade Q235. The steel of a higher grade has a yield strength of ≥355MPa and is advantageous for mining, cement, and grain storage as it can withstand higher pressures.
- Right-Size Zinc Coating Based on Environmental Conditions: For coastal, high humidity, and sites of corrosive chemicals, select a zinc coating of Z450/Z600 (instead of Z275). The thicker zinc coating extends corrosion protection, and premature rust and costs of maintenance are avoided.
- Use the Double Sealing System for Hygroscopic and/or Powdery Materials: If the storage of sensitive materials such as fertilizers, powders, or food-grade grains is an issue, the double sealing system (EPDM + PU sealant) should be used. It strongly minimizes air and moisture ingress to avoid spoilaging, clumping, and dusting loss of the materials, while helping to maintain quality and safety of the end products.
- Modify Roof & Structure for Weather Load Design: For sites with high winds or heavy snow, combine a truss design with an optional seismic protection system of up to Zone 9. This ensures that the designed systems will remain operational and unscathed after an extreme weather event for the safety of the personnel and clients.
3
Capacity & Investment Reference
In comparison with other storage systems, bolt-assembled silo systems are a great solution to a bulk storage need, particularly for small to large capacity needs, providing easy and economical storage with rapid onsite construction.
| Unit Capacity (t) | Diameter (m) | Total Height (m) | Footprint (m²) | Investment (USD) |
|---|---|---|---|---|
| 500 | 7 | 14 | 38.5 | $33,000 – $53,000 |
| 1,000 | 10 | 14 | 78.5 | $47,000 – $73,000 |
| 5,000 | 18 | 22 | 254.5 | $80,000 – $120,000 |
| 10,000 | 22 | 26 | 380.2 | $160,000 – $213,000 |
Technical Highlights
- Unit Cost Efficiency: Large-capacity silos are more economical for tonnage and centralized storage.
- Land Utilization: Large silo diameters are more economical for land cost and more ton storage.
- Height Flexibility and Cost Predictability: Smaller silos provide greater flexibility to the height, and larger silos provide greater predictability for costs.
- Economic Scale: 10,000-ton class spiral silos are the most cost and land efficient silos for new or expansion storage.
4
Construction & Maintenance
The bolted structure of prefabricated steel silos has modular construction which allows easy maintenance and rapid component replacement, minimizing construction and operating costs.
| Parameter | Specification Value | Impact on Investment |
|---|---|---|
| Construction Period | 10-20 days for a single silo; 30-60 days for silo group/farm; all silos assembled on-site without large compaction equipment | A shorter construction cycle reduces labor and site rental costs; an expedited construction schedule increases costs by 15-25% |
| Foundation Load | 8-12 t/m² for normal silos; 15-20 t/m² for large-capacity, heavy-duty silos; a weak soil foundation may require treatment | Higher foundation load standards increase costs and foundation treatment increases the overall investment by 10-30% |
| Maintenance Cycle | Monthly inspection is routine, annual inspection is comprehensive; anti-corrosion remodeling is every 5-8 years | Regular maintenance increases service life and reduces the cost of other maintenance; a maintenance neglect results in an increase of over 40% to repair the silo |
| Seismic Rating | Standard of 7 degree seismic resistance (up to 9 in high seismic resistance areas) | Every increase of seismic rating requires silo reinforcement and component replacement; the total cost goes up by 12-20% |
5
Material-Specific Silo Design
Steel silos are often the only practical solution for the bulk storage of solid materials. However, inappropriate design may lead to material flow problems, such as blockages, along with costly inefficiencies during material extraction. Material-Specific Silo Design addresses these issues by utilizing the physical and chemical characteristics of the material for the design of the silo structure and flow geometries.
Technical Highlights
| Material Type | Bulk Density Range | Rec. Thickness (mm) | Special Design Requirements |
|---|---|---|---|
| Grain | 0.70 ~ 0.75 t/m³ | 2.0 – 6.0 mm | External stiffeners to prevent accumulation |
| Cement | 1.10 ~ 1.25 t/m³ | 2.5 – 6.0 mm | Powder flow characteristics and anti-blocking discharge system |
| Fly Ash | 1.30 ~ 1.50 t/m³ | 2.5 – 6.0 mm | |
| Mineral Powder | 1.50 ~ 2.20 t/m³ | 2.5 – 6.0 mm | |
| Lump Ore ≤80mm | 1.50 ~ 2.8 t/m³ | 2.5 – 6.0 mm | Internal wear-resistant lining |
Specific Hopper Design Parameters
| Material | Typical Bulk Density (t/m³) | WALL FRICTION ANGLE (°) | RECOMMENDED HOPPER HALF-ANGLE |
|---|---|---|---|
| Wheat | 0.75 t/m³ | 24 – 28 | ≥ 35 |
| Paddy (Rice) | 0.58 t/m³ | 22 – 26 | ≥ 35 |
| Corn | 0.72 t/m³ | 22 – 26 | ≥ 35 |
| Cement Powder | 1.20 t/m³ | 25 – 35 | ≥ 45 |
| Fly Ash | 1.45 t/m³ | 28 – 38 | ≥ 50 |
| Mineral Powder | 1.80 t/m³ | 30 – 40 | ≥ 55 |
| Lump Ore ≤80mm | 1.60 t/m³ | 35 – 45 | ≥ 60 |
6
Steel Grades
The storage conditions and type of corrosion that needs to be considered will determine the selection of galvanized and/or stainless steels.
6.1 Galvanized Steel Levels
| Level | Coating (g/m²) | Environment |
|---|---|---|
| Z-275 | 275 | Dry indoor / Regular Agri |
| Z-450 | 450 | Outdoor general industrial |
| Z-600 | 600 | Coastal / Corrosive |
| Verinox | Composite | Zinc outer + SS304 inner |
6.2 Structural Base Metal
| Grade | Yield Point | Best Use Case |
|---|---|---|
| Q235B | 235 MPa | Common welded silos |
| Q345B | 345 MPa | High capacity / Main structures |
| 304 / 304L | 205 MPa | Food grade / Anti-corrosion |
| 316 / 316L | 170 MPa | Chemical / Chloride environment |
Technical Highlights
- Steel Strength Selection: Q345B (345 MPa yield strength) is the optimum choice for large, high capacity silos, while Q235B is recommended for medium and small silos.
- Galvanization by Environment: Z-275 is adequate for inland agricultural silos, while Z-600 or long-term corrosion-resistant Verinox coatings should be specified for coastal or other corrosive environments.
- Stainless Steel Selection: 304/304L should be used in food-grade or mild corrosion environments, while 316/316L should be specified for chloride and other chemically-polluted corrosion environments.
- Composite Coating Advantage: Verinox coatings are suitable for humid and material-corrosive environments, as they combine corrosion protection with a cost-effective solution.
7
Special Anti-Corrosion Coating Systems
For reliable corrosion protection throughout the designed service life, select the appropriate coating system and coating thickness for the silo’s corrosion environment category.
| Parameter Item | Standard Configuration | Optional Upgrade | Description |
|---|---|---|---|
| Applicable Areas | Silo external wall / roof / connection joints | Silo internal wall / bottom / highly corrosive areas | Coating systems design to allow for diverse applications |
| Primer Type | Zinc-rich primer | Inorganic zinc-rich primer | Base level of anti-corrosion and cathodic protection are provided |
| Intermediate Coat Type | Epoxy intermediate coating | High-build high-solid epoxy intermediate coating | Barrier protection is enhanced; thickness is increased |
| Topcoat Type | Polyurethane topcoat | Fluorocarbon topcoat / weather-resistant polysiloxane topcoat | Improved weathering capacity, color retention, UV resistanc |
| Total Dry Film Thickness | 180–220 µm | 250–320 µm | Engagement thickness is determined by the environmental rating of the project |
| Adhesion Strength | ≥ 5 MPa | ≥ 6 MPa | Ensures long adhesion stability for the coating |
| Salt Spray Resistance | ≥ 1000 h | ≥ 2000 h | Designed for use in highly corrosive and coastal environments |
| Application Method | Spray application / brush application | Shop pre-coating + on-site touch-up coating | Consistency of application improved and anti-corrosion enhanced |
| Surface Preparation Grade | Sa 2.5 | Sa 2.5 / St 3 | Surface preparation of the substrate is required before coating |