Department of Civil and Environmental Engineering (PDF)

Department of Civil and Environmental Engineering (PDF)

This study was made possible by a generous financial support provided by Nabih Youssef & Associates Structural Engineers, and NUCOR Research and Development. The senior author also received a stipend from the G. S. Agarwal Fellowship Fund at the Department of Civil & Environmental Engineering while working on this project. The authors acknowledge the contribution of Dr. Gustavo Parra-Montesinos and Dr. K.Y. Kim to the experimental phase of this study (Chapter 3). The opinions and views expressed in the report are solely those of the authors and do not necessarily reflect those of the sponsors.



Special Truss Moment Frame (STMF) is a relatively new type of steel structural system that was developed for resisting forces and deformations induced by severe earthquake ground motions. The system dissipates earthquake energy through ductile special segments located near the mid-span of truss girders. STMFs generally have higher structural redundancy compared to other systems because four plastic hinges can form in the chords of one truss girder. The redundancy can be further enhanced if web members are used in the special segments. Simple connection details are adequate for girder-to-column moment connections. Another advantage of using STMF system is that the truss girders can be efficiently used over longer spans and higher overall structural stiffness can be achieved by using deeper girders. In addition, the open-webs can easily accommodate mechanical and electrical ductwork. As a consequence, this system is gaining popularity in the U.S., especially for hospital and commercial buildings. Research work carried out during the Nineties led to the formulation of design code provisions. However, current design practice generally follows elastic analysis procedures to proportion the frame members. Therefore, it is possible that story drifts and yielding in the special segments may not be uniformly distributed along the height of the structure and may be concentrated in a few floors causing excessive inelastic deformations at those levels. Thus, the intended deformation limits and yield mechanism may not be achieved when an STMF is subjected to strong earthquakes.

We do not host this file(s) on our website. If this file(s) is yours, please report it to us, we will remove it within 24 hours.