Connections & installation
Bolts vs. Screws in Steel Connections
Compare bolted and screw-fastened steel connections by assembly, access, documentation, and inspection needs without treating them as interchangeable.
Compare the complete connection, not the fastener silhouette
A common through-bolted steel connection uses a bolt with a matching nut and the specified washer arrangement. A typical self-drilling screw connection engages the supporting steel with its threads. These descriptions explain familiar arrangements, but they do not define every specialty product or establish which system suits a project.
Start with the approved connection detail. Identify all components and the intended installation method before comparing alternatives. A proposal to replace several screws with one bolt changes more than the purchasing quantity; it requires review of the actual connection and surrounding members.
References: 2025 Specification for Structural Joints Using High-Strength Bolts (PDF) · Fastening information for cold-formed steel construction
Understand that bolted joints have their own requirements
The RCSC specification addresses high-strength bolted structural joints, including joint categories and associated installation and inspection requirements. A detail calling for a particular bolted joint cannot be reduced to a generic instruction to tighten until it feels secure.
For procurement, record the specified bolt assembly, applicable joint requirement, and supporting documents. Keep these requirements distinct from anchor rods connecting steel to concrete, which are another application. Similar terminology or a visible nut does not mean the same rules govern both conditions.
References: 2025 Specification for Structural Joints Using High-Strength Bolts (PDF)
Use practical coordination questions
This table helps organize a comparison for review. It does not rank the systems or authorize a change.
| Question | Bolted steel joint | Screw-fastened steel joint |
|---|---|---|
| What identifies the system? | Bolt, nut, washer, joint, and hole requirements | Exact screw, connected materials, and detail |
| What access is needed? | Access required by the specified assembly and method | Tool access and verification of the required installed condition |
| What changes require review? | Assembly, hole, joint, or member changes | Product, pattern, or connected-material changes |
| What closes the record? | Required installation and inspection evidence | Required installation and inspection evidence |
Bring access and fabrication into the discussion
A connection that is easy to draw may be difficult to assemble after neighboring work is complete. Show where tools, nuts, washers, or inspection views must fit. Ask whether the planned sequence preserves the required access rather than substituting a different connection at the last moment.
Fabrication information also belongs in the review. Existing holes, shop-prepared pieces, and member geometry can affect how a proposed change is evaluated. Supply the actual condition and drawings, not merely the diameter of the fastener that is available. Keeping the complete picture visible prevents a purchasing shortage from becoming an undocumented fabrication change.
Example: an inaccessible nut location
Imagine that a planned enclosure blocks access to a nut at a bolted connection. Document the location, detail, and installation sequence, then ask the project team to resolve the access conflict. A suggestion to use screws instead should remain a proposal until the responsible designer reviews it.
The accepted solution may involve coordination or revised sequencing rather than a new fastener. Record the actual resolution so that later trades do not recreate the conflict. If the connection is revised, update the material list, fabrication information, and inspection reference together.
- Identify the approved connection system.
- Check assembly and inspection access before enclosure.
- Treat a system change as a design review item.
- Keep the final detail and installed-product record aligned.
Make the purchase description unambiguous
Separate bolts, nuts, washers, screws, and specialty accessories into the package structure required by the accepted system. Identify which components must be supplied together and retain traceability information requested by the project. A quote with fewer lines is not necessarily clearer if it conceals an unresolved assembly. Before release, compare the complete delivered package with the approved record so the installer does not need to improvise a missing component.
Common questions
Are bolts always stronger than screws?
Connection performance depends on the complete designed assembly, including the members and loading. Comparing fastener names or diameters alone does not answer that question.
Can I use structural bolt tightening rules for anchor rods?
Do not assume they apply. Anchor rods and steel-to-steel bolted joints are different applications; use the governing detail and requirements for the actual connection.
Sources & further reading
Use the current documentation for the exact product and project. Source links do not imply a partnership or endorsement.
- 2025 Specification for Structural Joints Using High-Strength Bolts (PDF) Research Council on Structural Connections
- Fastening information for cold-formed steel construction Simpson Strong-Tie
Prepared with AI assistance. Linked references require current project-specific review. How these guides are prepared.
Prepare a supply inquiry
- Record the project drawing or detail and the specified product, profile, or system.
- List the complete configuration, physical units, quantities, and cuts per piece.
- Request current manufacturer documents; confirm compatibility, price, and availability before ordering.
- Obtain the responsible professional's review for loads, code requirements, or installation.