Anchoring Systems for Steel Structures

At a glance

What this guide helps you decide

Scope

Compare concrete, asphalt, gravel, and ground anchoring by load path, substrate, installation, inspection, corrosion, and design documentation.

Most useful when

• •The building system, base condition, and design documents identify a compatible anchor type.
• •Anchor location, embedment, spacing, and edge distance can be installed as specified.

Pause and verify when

• ×The base material or soil has not been evaluated for the proposed anchor.
• ×A generic anchor is being substituted for the engineered or manufacturer-specified connection.

Alternatives to keep open

• Engineered concrete anchorage: For permanent structures and higher or specifically designed loads.
• Approved ground-anchor system: For eligible soil and structure combinations when concrete is not required.

Cost drivers

Anchor hardware is usually only one part of the cost. Base preparation, testing, engineering, reinforcement coordination, special inspection, and corrective work can matter more.

Common mistakes

• Choosing anchors after the slab is poured.
• Installing too close to an edge or into unsuitable material.
• Assuming more anchors compensate for an incompatible detail.

Still needs project-specific verification

• The exact anchor schedule and base requirements in the approved documents.
• Existing concrete strength, thickness, reinforcement, edge distances, soil, or asphalt suitability as applicable.

Useful next step

Choose the supporting foundation →

Anchors can only be evaluated with the base they connect to.

Anchors transfer uplift, shear, and overturning forces from the steel frame into concrete, pavement, soil, or another supporting system. The correct anchor depends on the exact building, loads, substrate, edge distances, spacing, corrosion exposure, installation method, and approved design.

Do not choose from the surface label alone

Supporting condition	Questions to answer
Concrete	Strength, thickness, reinforcement, cracks, edge distance, anchor spacing, embedment, and condition
Asphalt or pavement	Thickness, temperature, subbase, deterioration, pullout/shear capacity, and approved product data
Gravel or native ground	Soil type, compaction, groundwater, frost, pullout capacity, corrosion, and installation verification
Existing foundation	Original design, additions, damage, elevations, compatibility, and field survey

An anchor that works in one substrate may be unsuitable in another. A generic pin, wedge, screw, or helical anchor is not a universal solution.

Concrete anchors

Expansion anchors, concrete screws, cast-in anchors, and other systems have different requirements for drilling, cleaning, embedment, spacing, edge distance, concrete strength, torque, corrosion protection, and inspection. Use the manufacturer’s technical data and the approved structural design.

Ground and pavement anchors

Helical, auger, driven, or other ground systems rely on soil engagement and installation conditions. Record the required depth, torque or refusal criteria, spacing, corrosion protection, test method, and acceptance record. Asphalt systems require data for the pavement and subbase; do not assume the asphalt behaves like concrete.

Installation and inspection

The record should identify:

• anchor product and configuration;
• location, spacing, embedment, edge distance, and orientation;
• substrate condition and any repairs;
• drilling, cleaning, torque, depth, or installation method;
• required proof tests, special inspections, photographs, or as-built survey;
• responsibility for substitutions, damage, and field changes.

Match the evidence to the substrate

An anchor decision is incomplete when the substrate is described only as “concrete,” “asphalt,” or “ground.” Collect the evidence that controls capacity and installation before comparing products.

Unknown	Evidence to collect
Existing concrete capacity	Thickness, strength records if available, reinforcement, cracks, edge distances, and a field condition check
Soil or gravel resistance	Soil description, compaction or test information, groundwater and frost conditions, and the approved installation method
Pavement support	Pavement thickness, subbase, deterioration, temperature conditions, and product data for the complete assembly
Existing-building compatibility	Original plans, additions, elevations, damage, and the exact point where the new reaction enters the structure

If the supporting condition cannot be documented, the next step is investigation or a site-specific design—not a stronger-looking anchor selected from a generic chart. Record who accepts the substrate and who is responsible for testing, repairs, substitutions, and field changes.

Warranty and modification scope

Read the written warranty for anchor requirements, installer conditions, maintenance, corrosion, relocation, unapproved modifications, and claim evidence. A warranty or wind label does not replace the design of the load path.

Anchor worksheet

Item	Record
Building and design criteria	Size, enclosure, wind, snow, seismic, exposure
Supporting system	Concrete, asphalt, gravel, soil, existing foundation
Anchor data	Product, size, spacing, embedment, corrosion protection
Installation	Tools, torque/depth, temperature, crew, sequence
Verification	Inspection, testing, photographs, as-built record
Scope limits	Foundation, drainage, repairs, substitutions, warranty

See the site-prep foundation guide, engineering guide, and high-wind guide for related decisions.