Design of Connections in Steel Structures Course

Lesson 1 • Limit States and Failure Modes

Strength and serviceability limit states define acceptable connection performance. Identifying governing failure modes is the foundation of safe design.

Lesson 2 • Classification of Steel Connections

Connections are classified by rigidity, load type, and geometry. This taxonomy guides selection of appropriate design models throughout the course.

Lesson 3 • Force Transfer Mechanisms

Bearing, friction, and fusion are the primary force transfer mechanisms. Recognizing each mechanism enables accurate limit-state identification.

Lesson 4 • Role of Connections in Steel Structures

Connections transfer forces between members and define structural behavior. Understanding their role frames every design decision in subsequent chapters.

Lesson 1 • Bolt Group Analysis Methods

Eccentric shear on bolt groups requires elastic or instantaneous center methods. Selecting the correct method balances accuracy with design efficiency.

Lesson 2 • Tension Connections with Bolts

Prying action amplifies bolt tension beyond applied loads. Accounting for prying is essential for safe hanger and flange connection design.

Lesson 3 • Combined Shear and Tension in Bolts

Eccentric loads and moment connections subject bolts to simultaneous shear and tension. Interaction equations ensure no single bolt is overstressed.

Lesson 4 • Shear Connections with Bolts

Bolt shear capacity depends on shear plane location and bearing conditions. Calculating nominal and design strengths anchors the limit-state design process.

Lesson 1 • Fillet Weld Strength and Sizing

Fillet weld capacity depends on effective throat, length, and electrode strength. Minimum and maximum size limits prevent cracking and lamellar tearing.

Lesson 2 • Weld Quality and Inspection Standards

Weld defects reduce capacity and initiate fatigue cracks. Specifying inspection methods and acceptance criteria ensures fabricated welds meet design assumptions.

Lesson 3 • Weld Types and Joint Geometry

Fillet, groove, plug, and slot welds serve distinct structural roles. Matching weld type to joint geometry optimizes strength and fabrication economy.

Lesson 4 • Weld Group Analysis Under Eccentric Loads

Eccentric shear and moment loads create non-uniform stress in weld groups. Elastic and instantaneous center methods quantify peak weld demand accurately.

Lesson 1 • Clip Angle and Double Angle Connections

Clip angles provide flexible end connections with high rotational capacity. Leg flexibility and bolt layout control the distribution of shear and secondary moment.

Lesson 2 • Coped Beam End Conditions

Coping removes beam flanges to clear supporting members, reducing local strength. Block shear, flexural yielding, and buckling checks are all required at coped ends.

Lesson 3 • Single-Plate Framing Connections

Single-plate connections simplify erection but require careful eccentricity checks. Plate thickness limits and weld sizing prevent premature yielding or fracture.

Lesson 4 • Seated Beam Connections

Seated connections support beam reactions through a bearing seat angle or plate. Stiffened and unstiffened seats suit different load magnitudes and geometries.

Lesson 1 • End Plate Moment Connections

End plate connections use a plate welded to the beam end and bolted to the column. Flush and extended end plate configurations suit different moment magnitudes.

Lesson 2 • Directly Welded Flange Connections

Direct weld of beam flanges to column flanges achieves full moment transfer without plates. Weld access holes and backing bars require careful detailing for quality and fatigue.

Lesson 3 • Behavior of Moment Connections

Moment connections must transfer both shear and moment while maintaining rotation compatibility. Classifying connections by stiffness determines their effect on frame analysis.

Lesson 4 • Column Web and Flange Stiffening

Concentrated flange forces from moment connections can buckle or yield the column panel zone. Continuity plates and doubler plates restore column capacity where needed.

Lesson 1 • Moment Base Plate Design

Moment at the column base creates non-uniform bearing and anchor rod tension. Iterative pressure distribution analysis determines plate thickness and rod demands.

Lesson 2 • Axially Loaded Base Plate Design

Concentric compression spreads column load over the concrete bearing area. Plate dimensions and thickness are governed by bearing pressure and cantilever bending.

Lesson 3 • Anchor Rod Design for Tension

Uplift and moment loads place anchor rods in tension, requiring embedment and ductility checks. Concrete breakout and pullout must be verified alongside rod tensile capacity.

Lesson 4 • Detailing and Constructability of Base Plates

Anchor rod templates, leveling nuts, and grout pockets affect erection accuracy. Proper detailing prevents field problems and ensures load transfer as designed.

Lesson 1 • Brace-to-Gusset Connections

Braces connect to gussets via bolts or welds, transferring large axial forces. Clearance zones and hinge lines allow brace rotation without inducing plate fracture.

Lesson 2 • Gusset-to-Frame Connections

Gusset plates attach to beams and columns through welds or bolts along their edges. Interface forces include shear, normal force, and moment that must be distributed uniformly.

Lesson 3 • Gusset Plate Design and Sizing

Gusset plates distribute forces from braces and diagonals to chords and columns. Plate geometry, thickness, and edge conditions govern yielding and buckling resistance.

Lesson 4 • Force Analysis at Panel Points

Truss connections must equilibrate axial forces from multiple converging members. Accurate force resolution prevents unintended eccentricity and secondary bending.

Lesson 1 • Connection Design Review and Quality Control

Systematic review catches errors before fabrication and erection. Checklists, peer review, and constructability assessments are essential professional practice tools.

Lesson 2 • Finite Element Analysis of Connections

FEA reveals stress concentrations and load redistribution beyond simplified models. Validating FEA models against test data ensures reliable predictions for complex details.

Lesson 3 • Fatigue Design of Connections

Cyclic loading degrades connection capacity through crack initiation and propagation. Fatigue categories and stress range limits govern detail selection in dynamic structures.

Lesson 4 • Semi-Rigid Connection Modeling

Semi-rigid connections redistribute moments between beams and columns, affecting frame drift. Moment-rotation curves quantify stiffness for use in advanced frame analysis.