Abstract:
The Linked Column Frame (LCF) is a new brace-free lateral structural steel system intended for rapid return to occupancy performance level. LCF is more resilient under a design level earthquake than the conventional approaches. The structural system consists of moment frames for gravity that combine with closely spaced dual columns (LC) interconnected with bolted links for the lateral system. The LC links are sacrificial and intended to be replaced following a design level earthquake. The centerpiece of this work was a unique full-scale experiment using hybrid testing; a combination of physical test of a critical sub-system tied to a numerical model of the building frame. Hybrid testing allows for full scale study at the system level, accounting for the uncertainties via experimental component and having the ability to model more conventional behavior through numerical simulation. The experimental subsystem consisted of a two-story LCF frame with a single bay while the remainder of the building was numerically modeled. Two actuators per story were connected to the specimen. The LC links have been designed to be short and plastically shear dominated and the LCF met the design intent of 2.5% inter-story drift limits. For evaluating the LCF response, hybrid testing was performed for ground motion at three different intensities; 50%, 10% and 2% probability of exceedance in 50 years for Seattle, Washington ground motions. The system exhibited three distinct performance levels; linearly elastic, rapid return to occupancy where only the replaceable links would yield, and collapse prevention where the gravity beam components also became damaged. Results demonstrated a viable system under cyclic and seismic loading, offering a ductile structural system with the ability to rapidly return to occupancy.
Bio:
Dr. Arlindo Pires Lopes earned his undergraduate degree in Civil Engineering from the Federal University of Amazonas, Brazil. After moving to the United States, he completed his master’s and Ph.D. degrees in Structural Engineering from Portland State University. He joined the School of Engineering at Amazonas State University in 2005 and his research bridges large-scale experiments with computational mechanics investigations using both finite and boundary element methods. Professor Lopes is a licensed Professional Engineer with over 25 years of experience having supervised and monitored several building construction and highway engineering projects. He works in the following areas: reinforced and prestressed concrete structures, steel structures, instrumentation and monitoring of structures, highway bridges, and earthquake engineering. Outside the classroom, Professor Lopes is an avid jiu-jitsu practitioner and enjoys swimming and playing soccer.