INSTRUCTOR: Kamalpreet S. Kalsi, P.E., S.E.

Purpose and Background

Usually a building’s structural system is decided very early on in the design phase. For the same amount of stiffness and strength, steel moment frames offer the maximum open space to the architect/owner as compared to a shear wall or braced frame. Though all three types of moment frames (special moment frame, intermediate moment frame, and ordinary moment frame) rely on resisting seismic demands by moments in beams and columns, they all are expected to have significantly different non-linear deformations based on the detailing.

The benefit of open space in design comes with additional costs. Higher steel weight per square foot, cost of welding doubler and continuity plates usually result in moment frames being more expensive than shear wall or brace frames. This webinar outlines all three types of moment frames with a detailed example to help engineers design a moment frame structure. The webinar also covers the building code requirements on each major component in moment frame design and provide practical recommendations to design engineer.

Primary Discussion Topics

• Moment frames history and code development
• Moment frames design principle
• Design and detailing changes after 1994 Northridge earthquake
• Prequalified connections and other permissible options per code
• Major design elements and their detailing
• Example of complete design of 3- story structure with moment frames

Learning Outcomes

• Explain the history of steel moment frames and major code developments as a result of lessons learned from past earthquakes (1994 Northridge)
• Identify how to initially size moment frames members with a given floor plan
• Discuss the requirements and importance of ductile detailing
• Explain the basic difference between special, intermediate and ordinary moment frames and code restrictions for each type based on seismicity, height and occupancy category
• Design a moment frame building and understand the code requirements, important detailing aspects with detailed sketches

Webinar Benefits

• Design moment frame structures
• Understand the criteria governing design
• Discuss welding requirements and importance of protected zones
• Recognize major design components and their ductile detailing
• Explain practical design consideration in moment frames

Intended Audience

• Structural and civil engineers involved in design of buildings
• Government/public agency engineers
• Building owners

Webinar Outline

• History
• Brief history of moment frame construction
• Current design codes and effect of 1994 Northridge earthquake
• Principles of moment frame design
• Design components
• Columns, column splices and column base fixity
• Prequalified moment connections, ductile detailing, beams and lateral bracing
• Panel zones, continuity plates and doubler plates
• Collectors/drags and p-delta effects
• Other Considerations
• oStrength and drift requirements
• Welding requirements
• Member compactness
• Moment frame types
• Special moment frame
• Intermediate moment frame
• Ordinary moment frame
• Design example
• Code based design for a 3 story moment frame building with details concentrated on special moment frame