FRAME3D is a program for the three-dimensional nonlinear analysis of buildings. It aims to overcome the computational challenges posed by full 3D analysis of buildings subject to earthquake ground motion. The element library consists of a plastic hinge beam element, an elastofiber beam element, a panel zone element, a 4-noded diaphragm element to model floor slabs, and an elastic translational/rotational spring element to model foundations and supports. The program utilizes a Netwon-Raphson iteration strategy applied to an implicit Newmark time-integration scheme to solve the nonlinear equations of motion at each time-step. Geometric nonlinearity and shear deformation are included in the formulation.
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CLICK ON THE IMAGE ABOVE TO VIEW THE MOVIE OF A WATER TANK COLLAPSING UNDER STRONG NEAR-SOURCE GROUND MOTION. ANALYSIS WAS DONE USING FRAME3D. You can view many more animations of tall building response during earthquakes here.
Problems that have been successfully solved include 20-story moment frame steel buildings subject to strong ground motion from near-source earthquakes. This program is currently being used to model the damage to tall buildings in the Los Angeles and San Fernando basins from large scenario earthquakes on nearby faults such as the San Andreas fault simulated using the seismic wave propagation program, SPECFEM3D, developed at the Seismological Laboratory at Caltech.
Future plans for this program include populating the element library with other structural elements such as braces, walls etc., parallelizing the program so that it can handle super-highrise buildings and long-span bridges. In addition, this site will offer free analyses services where registered users can analyze the buildings in the current building database with their ground-motion histories or add a building model to the building database and analyze it to one of the available sets of ground motion records in the ground motion database. In either case, the user building models and ground motion records will be added to the respective databases on this site for public use.
The first version of the program was developed by Dr. Swaminathan Krishnan (Assistant Professor, Civil Engineering) during his Ph.D. research under the guidance of Dr. John F. Hall (acting Vice-President for student affairs, Dean of students, Professor, Civil Engineering and Applied Mechanics) in California Institute of Technology. Dr. Krishnan is a registered Structural Engineer (S.E.) and Professional Engineer (P.E., Civil) in the State of California.
Keywords: Tall buildings, beam element, steel moment frames, steel braced frames, earthquakes, near-source ground motion, time-history analysis, structural analysis, pushover analysis, structural design, dynamic analysis, three-dimensional analysis, floor slabs, diaphragm element, plastic hinge, fiber, elastofiber element, panel zone, finite element method.
NEWS
November 20, 2005
1. Version 1.1 of the program and user guide has been released. Click on CONTACT for more information.
June 30, 2004
1. Building damage is now categorized using the FEMA-356 acceptance criteria. Thus the performance of the structural model is categorized as Immediately Occupancy (IO), Life-Safe (LS), Collapse Prevented (CP), or Collapsed (CO), based on the extent of plastic yielding at the ends of beams and columns and in the panel-zones and also on the story drift ratios.