Structural Steel Bolting Inspections: What You Need to Know

What Are Structural Steel Bolting Inspections?

Structural steel bolting inspections are a critical part of ensuring the integrity, safety, and compliance of steel structures. These inspections focus on verifying that bolts, nuts, and washers used in steel connections meet the specified design and installation requirements outlined by the International Building Code (IBC) and other relevant standards, such as the AISC (American Institute of Steel Construction) Steel Construction Manual and RCSC (Research Council on Structural Connections) specifications.

Why Are Bolting Inspections Important?

Bolts play a key role in transferring loads and maintaining structural stability. Proper installation and verification are essential to prevent failures that could jeopardize the safety of a structure. Inspections help:

• Ensure compliance with project specifications and industry standards.
• Identify defects or improper installation that could lead to premature failure.
• Protect against potential safety risks and costly repairs down the road.

What Codes and Standards Govern Structural Bolting?

Structural bolting inspections are guided by:

• IBC (International Building Code): Provides general requirements for special inspections.
• AISC (American Institute of Steel Construction): Offers specifications for structural steel connections.
• RCSC (Research Council on Structural Connections): Defines standards for bolt installation, inspection, and quality control.
• ASTM (American Society for Testing and Materials): Specifies material properties for bolts, nuts, and washers.

These codes ensure that bolting practices meet engineering, safety, and durability requirements.

What Types of Bolts Are Inspected?

Structural bolting inspections typically involve two primary types of bolts:

1. High-Strength Bolts: Commonly used in structural steel connections, including ASTM A325 and A490 bolts.
2. Common Bolts: Lower-strength bolts used for non-critical applications.

Inspectors evaluate both bolt types based on factors such as material properties, grade, and application.

What Are the Key Inspection Tasks?

The structural steel bolting inspection process includes:

1. Material Verification

Inspectors confirm that bolts, nuts, and washers meet the specified grades and standards by:

• Reviewing mill certificates and manufacturer documentation.
• Performing visual inspections to identify markings indicating bolt grade and manufacturer.

2. Pre-Installation Verification

Before installation, inspectors ensure:

• Bolts are free of defects such as corrosion or damage.
• Correct pairing of nuts, bolts, and washers.
• Lubrication requirements are met to achieve proper tensioning.

3. Installation Inspections

During installation, inspectors verify:

• Proper alignment and positioning of connected elements.
• Correct bolt tightening methods, such as turn-of-nut, calibrated wrench, or direct tension indicators (DTIs).
• Compliance with torque or tension specifications.

4. Post-Installation Verification

After installation, inspectors:

• Check for snug-tight or fully-tensioned conditions as specified by the design.
• Examine bolt stick-out to ensure threads are adequately engaged.
• Document inspection results and compliance.

What Are the Common Methods for Tension Verification?

Inspectors employ various methods to verify bolt tension, including:

• Turn-of-Nut Method: Rotating the nut a specified amount after snug-tightening.
• Calibrated Wrench Method: Using a torque wrench calibrated for the specific bolt.
• Direct Tension Indicators (DTIs): Devices placed under the bolt head or nut that flatten as tension is applied.
• Twist-Off Bolt Method: A specialized bolt with a splined end that breaks off at the proper tension.

What Are the Typical Challenges in Bolting Inspections?

Structural steel bolting inspections can encounter challenges such as:

• Improper Installation: Incorrect tensioning or misaligned bolts.
• Material Defects: Damaged or corroded bolts.
• Environmental Factors: Temperature and humidity affecting bolt performance.
• Documentation Gaps: Missing or inaccurate records of materials and procedures.

Addressing these issues requires a combination of skilled inspectors, thorough procedures, and close communication with contractors.

Who Conducts Bolting Inspections?

Structural steel bolting inspections are typically performed by certified special inspectors with expertise in:

• Construction materials testing.
• IBC special inspections.
• Bolting procedures and specifications.

Certifications such as ICC Structural Steel and Bolting Special Inspector or AWS (American Welding Society) credentials ensure inspectors have the required knowledge and skills.

What Should Be Included in an Inspection Report?

A comprehensive bolting inspection report includes:

• Details of bolts, nuts, and washers inspected (e.g., grade, size, manufacturer).
• Installation methods and verification techniques used.
• Observations of defects or non-compliance.
• Photos or diagrams as necessary.
• Summary of compliance with applicable codes and standards.

Why Choose Foundation Systems Engineering for Bolting Inspections?

At Foundation Systems Engineering, we understand the importance of accurate and reliable structural bolting inspections. With a dedicated team of certified inspectors and extensive experience in IBC construction special inspections, we provide:

• Comprehensive inspections for all structural bolting applications.
• Clear and detailed reporting for streamlined compliance.
• Expertise across a wide range of construction projects, including commercial, industrial, and infrastructure developments.

Serving clients across the South, including Virginia, West Virginia, Kentucky, Tennessee, and beyond, we ensure that your project meets the highest standards of safety and performance.

Ready to Schedule a Structural Steel Bolting Inspection?

Contact us today to discuss your project’s requirements. Foundation Systems Engineering is your trusted partner for all IBC construction special inspections, ensuring your structural steel connections stand the test of time.