Steel-to-Concrete Anchoring – Structural Fixing Solutions
Anchoring steel to concrete is a critical part of many structural and construction applications. Base plates, columns, brackets, support frames and secondary steelwork all depend on anchoring systems that are correctly selected for the loads, concrete condition, connection geometry and installation requirements.
Mechanical anchors, chemical anchors and concrete screws all offer different characteristics. The correct solution depends on the complete application rather than anchor diameter or load value alone.
For structural applications, product selection and structural anchor design are related but separate steps. Identifying a potentially suitable anchor does not replace verification of the complete anchorage against the applicable design requirements.
Why steel-to-concrete anchor selection matters
A steel-to-concrete connection transfers forces from the steel component into the concrete structure. The anchor therefore forms an important part of the complete connection rather than simply holding the fixture in position.
Incorrect anchor selection can contribute to:
- Insufficient resistance for the applied loads
- Problems with restricted edge distances or anchor spacing
- Unsuitable use in cracked concrete
- Installation difficulties on site
- Missing technical approvals or documentation
- Redesign, delays or unnecessary rework
Where steel-to-concrete anchors are used
Anchoring systems are used across a wide range of steel construction and building applications, including:
- Structural steel base plates
- Steel columns and support frames
- Brackets and connection plates
- Handrails and guardrails
- Machinery and equipment supports
- Mechanical and electrical supports
- Façade and building components
- Secondary steelwork
Main anchoring solutions for steel-to-concrete connections
Several anchoring technologies can be used to connect steel components to concrete. The appropriate option depends on the loads, concrete condition, available geometry, installation requirements and applicable product approval.
Mechanical anchors
Anchors that transfer loads through expansion, undercutting, interlock or another mechanical action within the concrete.
Chemical anchors
Bonded anchoring systems that use resin to secure a threaded anchor element or reinforcing bar within a prepared drill hole.
Concrete screws
Direct mechanical fixings that form a connection with the concrete when installed into a correctly prepared drilled hole.
Mechanical anchors
Mechanical anchors transfer load into the concrete through mechanisms such as expansion, undercutting or mechanical interlock. They can provide a practical solution where fast installation and, for suitable products, immediate loading are important.
Suitability still depends on the load case, concrete condition, embedment depth, edge distance, spacing and scope of the relevant product approval.
Chemical anchors
Chemical or bonded anchors use resin to transfer loads between the anchor element and the surrounding concrete. They can offer useful design flexibility where reduced expansion forces, bonded threaded rods or different embedment conditions are required.
Correct hole preparation, resin installation, temperature control and curing are particularly important to achieving the intended performance.
Compare mechanical and chemical anchors >
Concrete screws
Concrete screws provide a direct mechanical fixing for suitable steel-to-concrete applications. Their thread develops the connection with the concrete after installation into a correctly prepared drilled hole.
Depending on the specific product and approval, they can provide an efficient option for brackets, support systems, secondary steelwork and other steel components fixed to concrete.
Explore steel-to-concrete anchoring products
Already know which anchoring technology you need? Explore the relevant Fabory product categories.
Mechanical anchors
Explore heavy-duty anchoring products for demanding concrete fixing applications.
Chemical anchors
Explore bonded and chemical anchoring products for suitable concrete applications.
Concrete screws
Explore concrete screws in a range of head types, sizes and specifications.
How to choose the right anchoring solution
No single anchoring technology is automatically the best choice for every steel-to-concrete connection. Selection should be based on the actual project conditions.
Understand the applied loads
Determine whether the connection is subjected to tension, shear, combined loading or additional eccentric or bending effects. Load direction and magnitude influence both anchor selection and connection geometry.
Explore tension, shear and combined anchor loads >
Check the concrete and connection geometry
Concrete strength and condition should be considered together with edge distances, anchor spacing, embedment depth, member thickness and anchor-group configuration.
Where cracking can occur at the anchor location, the selected anchor must be suitable for cracked concrete where required by the design.
Understand cracked and non-cracked concrete >
Explore edge distance, spacing and embedment requirements >
Consider the installation method
The anchoring system must also be practical to install under the actual site conditions. Depending on the product, requirements may include controlled drilling, hole cleaning, defined embedment, tightening torque, curing time or installation-temperature limits.
Pre-positioned, through and stand-off fixing arrangements can also affect anchor length and connection behaviour.
Explore anchor installation and mounting methods >
Consider the service environment
Moisture, weather exposure, industrial conditions and other environmental factors can influence the required anchor material or corrosion protection. The selected solution should be suitable for the intended service conditions and expected service life.
What information do you need before designing an anchorage?
Having the key application information available before selecting or calculating an anchor makes it easier to identify a suitable solution.
Where applicable, have the following details ready:
- Concrete strength class
- Cracked or non-cracked concrete
- Tension and shear loads
- Number and position of anchors
- Base-plate or fixture dimensions
- Available edge distances
- Spacing between anchors
- Available embedment depth
- Concrete-member thickness
- Fixture thickness
- Environmental conditions
- Fire or seismic requirements where applicable
Once these parameters are known, the anchorage can be assessed against the relevant product data and structural design requirements.
Have the details ready? Use the Fabory Anchor Calculator >
ETA and DoP documentation
For structural anchoring applications, technical documentation is an important part of product selection.
A European Technical Assessment (ETA) provides product-specific performance information and defines the conditions under which the anchoring system has been assessed. These can include concrete condition, anchor dimensions, embedment, spacing, edge distances and installation requirements.
The Declaration of Performance (DoP) communicates the declared performance of a construction product where applicable.
The documentation should always relate to the exact product and intended application rather than assuming that the existence of an ETA alone makes every configuration suitable.
Learn more about ETA and DoP documentation >
Calculate steel-to-concrete anchors in accordance with EN 1992-4
For structural post-installed anchors in concrete, selecting a product from a published load value alone is not sufficient. The complete connection needs to be assessed against the actual loading, concrete condition and anchoring geometry.
The Fabory Anchor Calculator helps designers and engineers evaluate post-installed anchors for structural use in concrete in accordance with EN 1992-4.
Enter the project parameters to assess suitable anchoring solutions based on the actual application.
The calculator can help you:
- Assess tension and shear loading
- Calculate combined loading conditions
- Design for cracked and non-cracked concrete
- Consider anchor spacing and edge distances
- Evaluate different anchor configurations
- Assess fire and seismic conditions where applicable
- Understand why an anchor does not meet the entered requirements
- Generate calculation reports for project documentation
Use the Fabory Anchor Calculator >
Common steel-to-concrete anchoring mistakes
Many anchoring problems can be avoided by checking the application before the product reaches site.
- Selecting an anchor by diameter alone
- Using a single catalogue load value without verifying the complete anchorage
- Overlooking cracked-concrete requirements
- Ignoring anchor spacing and edge distances
- Using an anchor outside the conditions of its approval
- Failing to follow the specified installation procedure
From specification to installation with Fabory
A reliable steel-to-concrete connection requires coordination between design, procurement and installation. Fabory supports steel construction customers from initial anchor selection through to product supply and installation guidance.
Support can include:
- Mechanical and chemical anchoring solutions
- Concrete screws
- Support with anchor selection
- Fabory Anchor Calculator support
- Technical product information
- ETA and documentation support where applicable
- Installation guidance
- Product availability and project-focused supply
Considering these requirements before ordering can help reduce substitutions, missing documentation, installation delays and unnecessary rework.
Explore anchoring technical guidance
Build your understanding of the factors that influence anchor selection and structural design:
- Anchoring technical guidance >
- Types of anchors >
- Understanding anchor loads >
- Anchoring base materials >
- Cracked and non-cracked concrete >
- Anchoring conditions >
- Anchor installation and mounting methods >
- Practical anchor design >
Need support with a steel-to-concrete connection?
Steel-to-concrete anchoring can become complex where structural loads, restricted geometry, cracked concrete, multiple anchors or additional fire and seismic requirements are involved.
Fabory's specialists can help you assess the application, identify suitable anchoring options and access the supporting technical information.
Frequently asked questions about steel-to-concrete anchoring
Find answers to common questions about anchor selection, structural fixing and steel-to-concrete connections.
What anchors can be used to fix steel to concrete?
Steel can be fixed to concrete using anchoring systems including mechanical anchors, chemical or bonded anchors and concrete screws. The appropriate solution depends on the loads, concrete condition, connection geometry, installation method and scope of the relevant product approval.
Should I use a mechanical or chemical anchor?
Neither system is automatically better. Mechanical anchors can provide efficient installation and, for suitable products, immediate loading. Chemical anchors can offer useful design flexibility and reduced expansion forces. The correct choice depends on the application, geometry, concrete condition, loads and installation requirements.
Can concrete screws be used for steel-to-concrete fixing?
Yes, where the specific concrete screw is suitable and approved for the intended application. The applicable loads, concrete condition, embedment depth, spacing and edge distances should always be checked.
Do I need an anchor suitable for cracked concrete?
Where cracking can occur at the anchor location, the selected anchor should be suitable for cracked concrete where required by the design. If the concrete cannot reliably be considered non-cracked, cracked-concrete conditions should be taken into account.
What information is needed to calculate a structural anchor?
Typical inputs include concrete strength and condition, tension and shear loads, anchor number and position, fixture geometry, edge distances, anchor spacing, available embedment depth, member thickness and any applicable fire or seismic requirements.
Can the Fabory Anchor Calculator help design a steel-to-concrete connection?
Yes. The Fabory Anchor Calculator helps assess post-installed anchors for structural use in concrete in accordance with EN 1992-4 using the loads, concrete conditions and anchoring geometry entered for the application.