Software BTM Component
BTM Component
The Software BTM Component enables the highly automated analysis, in a user friendly and practical graphical environment, of RC walls (rectangular and barbell shaped only) using the beam-truss model (BTM) in the finite element program FE-MultiPhys. The BTM Component capabilities include the efficient modeling and analysis conduct as well as the nonlinear behavior determination including capturing and identification of various critical failure modes of RC walls. It can also be used to model other than walls RC components such as beams, and columns.
The BTM is an accurate, simple, and computationally powerful seismic analysis method for RC walls and other components as well as for entire building and structural systems that has been developed over the last fifteen years resulting in numerous peer-reviewed and other publications. The BTM has been extensively validated using the experimental test results of twenty-six (26) specimens mostly RC structural walls of various section shapes and configurations including rectangular (R) and barbell (B) sections, flanged walls of various sectional shapes (T, I, C, H) and coupled walls via coupling beams and/or slabs. The BTM has also been used to model shear-critical RC columns and this publication was used from one of the winners of the 2021 PEER’s blind prediction contest on the cyclic behavior of a shear-critical RC column. Finally, the BTM has been used to capture the experimentally tested seismic behavior of reinforced masonry walls as well as of masonry infilled RC frames. More information regarding the BTM are found in the BTM Component Report.
The software BTM Component enables the advanced and practical seismic analysis (static cyclic and monotonic) of RC walls and other components (beams, and columns), of rectangular or barbell shape section, using the beam-truss model (BTM) in the finite element program FE-MultiPhys. The capabilities of the BTM Component include the efficient modeling (pre-processing), analysis conduct, post-processing, and nonlinear behavior determination including identification of various critical failure modes, Figure 1, of RC components. The main capabilities of the program are:
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Fast modeling of RC components of rectangular and barbell sections. Each section definition consists of three distinct regions: two boundary elements and the interior web (Figure 2)
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Nonlinear static (cyclic and monotonic) analysis for in-plane loading controlled at a single elevation
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Automatic definition and calibration of advanced material models for reinforcing steel and concrete (confined and unconfined)(Figures 3 and 4)
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Efficient modeling of bar buckling and rupture at the material level (Figure 3)
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Unconfined and confined concrete material modeling including softening and biaxial effects (Figure 4)
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Fully-automated mesh generator accounting for the angle of inclination of the diagonal compression field of concrete (Figure 5)
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Explicit modeling of nonlinear flexure-shear-interaction: coupling the inelastic behavior of reinforcing steel in the longitudinal and transverse directions with the biaxial effects and softening of the diagonal compression field of concrete.
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Capturing various critical damage and failure modes for in-plane behavior such as: bar buckling and rupture, diagonal tension and compression, horizontal and vertical crushing of the web and boundary elements. (Figure 1)
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User-friendly post-processing and extraction of F-D and stress-strain responses of all elements and fibers (Figures 6 and 7)
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One-click summary of response including strain contours and failure modes identification (Figure 8)
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One-click report summary of the seismic performance of the component including mechanical properties, hysteretic behavior, force-displacement responses, strain responses, and failure mode identification. (Figures 9 and 10)
Enables the Fast Modeling, Advanced Seismic Analysis, and Failure Mode Identification of RC Components in a User-friendly Interface
Figure 1. Failure patterns of experimentally tested RC walls with confined boundary elements: (i) diagonal tension; (ii) web crushing; (iii) bar buckling and rupture; (iv) crushing of boundary elements; (v) boundary element web interface vertical crushing.
Figure 2. Main window of the graphical interface and Section Properties.
Figure 3. Reinforcing steel materials.
Figure 4. Confined and unconfined concrete materials.
Figure 5. Mesh Generation and Moment-Curvature.
Figure 6. Force - Displacement response.
Figure 7. Stress - Strain response of fibers.
Figure 8. One-click Summary of Response of seven strain contours and failure modes identification.
