Guide to Design Criteria for Bolted and Riveted Joints

How to Apply Guide to Design Criteria for Bolted and Riveted Joints

Mastering the design criteria for bolted and riveted joints is fundamental to ensuring the safety, integrity, and longevity of steel structures. This guide, rooted in extensive research and industry consensus, provides the essential framework for engineers to confidently design robust connections. A thorough understanding of these principles not only prevents structural failures but also enhances your professional reputation and efficiency in project delivery.

Before You Begin

Prerequisites:

• •Knowledge: A solid grasp of structural mechanics, statics, dynamics, and material properties of structural steel and fasteners is essential. Familiarity with fundamental concepts of load and resistance factor design (LRFD) or allowable strength design (ASD) principles is also expected.
• •Tools/Resources: Access to the "Guide to Design Criteria for Bolted and Riveted Joints" (Second Edition), applicable building codes (e.g., AISC Specification), engineering handbooks, and structural analysis software.
• •Time Required: Approximately 2-4 hours for initial review and comprehension, with ongoing reference time as needed during project design.

Step-by-Step Implementation

Step 1: Identify Connection Type and Fastener Requirements

Begin by clearly defining the type of structural connection you are designing (e.g., shear splice, moment connection, beam-to-column). Determine whether bolted or riveted fasteners are specified or appropriate for the application. This initial step dictates the subsequent design considerations and the relevant sections of the guide you will consult.

Step 2: Characterize Applied Loads and Load Combinations

Accurately determine all anticipated loads acting on the joint, including dead loads, live loads, wind loads, seismic loads, and their corresponding load combinations as stipulated by relevant design codes. The guide emphasizes understanding how these loads are transmitted through the connection.

Step 3: Evaluate Fastener Capacity in Shear

For each fastener in the joint, calculate its shear capacity. This involves considering the shear plane(s), the bolt or rivet material grade, and the nominal shear strength, often adjusted by factors accounting for bearing and potential slip, especially for slip-critical connections. Refer to the guide's sections on individual fastener behavior in shear.

Step 4: Assess Fastener Capacity in Tension

If the connection is subjected to tensile forces, determine the tensile capacity of each fastener. This calculation considers the bolt's or rivet's tensile strength, the net tensile area, and any potential reduction due to combined shear and tension or prying action.

Step 5: Analyze Combined Shear and Tension Effects

For connections experiencing both shear and tensile forces simultaneously, evaluate the interaction between these load types. The guide provides criteria for assessing the combined capacity, ensuring that the fastener does not fail under this biaxial stress state. This often involves interaction equations or diagrams.

Step 6: Verify Bearing and Prying Actions

Investigate the bearing stresses between the fasteners and the connected material, particularly in the vicinity of bolt holes. Additionally, assess any potential prying forces that can amplify the tensile stress in the fasteners, especially in moment connections. The guide offers insights into mitigating these effects.

Step 7: Consider Fatigue and Fracture Resistance

For connections subjected to cyclic loading, evaluate their fatigue resistance based on the details of the connection and the stress ranges experienced. Similarly, assess the potential for brittle fracture, considering material toughness and service temperatures, especially for high-strength bolts.

Common Pitfalls to Avoid

• • Inadequate Load Transfer Analysis: Failing to accurately trace the load path through the joint and into the fasteners can lead to underestimation of forces, resulting in insufficient fastener capacity.
• • Ignoring Slip-Critical Requirements: For connections designed to prevent slip, overlooking the importance of surface preparation and the coefficient of friction between faying surfaces can compromise the connection'