STR.C3 - Concrete Frame with Unreinforced Masonry Infill Walls
The following models are available:
STR.C3.LC | Structural, Concrete Frame Buildings with Unreinforced Masonry Infill Walls, Low-Rise, Low-Code
Structural components represent the structural system in the building.
Structural System: These buildings are similar to steel frame buildings with unreinforced masonry infill walls except that the frame is of reinforced concrete. In these buildings, the shear strength of the columns, after cracking of the infill, may limit the semi-ductile behavior of the system.
This is a “composite” structural system where the initial lateral resistance is provided by the infill walls. Upon cracking of the infills, further lateral resistance is provided by the concrete frame, “braced” by the infill, acting as diagonal compression struts. Collapse of the structure results when the infill walls disintegrate (due to compression failure of the masonry “struts”) and the frame loses stability, or when the concrete columns suffer shear failures due to reduced effective height and the high shear forces imposed on them by the masonry compression struts.
Low-Rise Building with 1-3 stories.
Design Level Approximate Basis:
1941-1975 construction in UBC Seismic Zone 2B, NEHRP Map Area 5
Post-1941 construction in UBC Seismic Zone 2A, NEHRP Map Area 4
Post-1975 construction in UBC Seismic Zone 1, NEHRP Map Area 2/3
Suggested Block Size: 1 EA (round up to integer quantity)
STR.C3.PC | Structural, Concrete Frame Buildings with Unreinforced Masonry Infill Walls, Low-Rise, Pre-Code
Structural components represent the structural system in the building.
Structural System: These buildings are similar to steel frame buildings with unreinforced masonry infill walls except that the frame is of reinforced concrete. In these buildings, the shear strength of the columns, after cracking of the infill, may limit the semi-ductile behavior of the system.
This is a “composite” structural system where the initial lateral resistance is provided by the infill walls. Upon cracking of the infills, further lateral resistance is provided by the concrete frame, “braced” by the infill, acting as diagonal compression struts. Collapse of the structure results when the infill walls disintegrate (due to compression failure of the masonry “struts”) and the frame loses stability, or when the concrete columns suffer shear failures due to reduced effective height and the high shear forces imposed on them by the masonry compression struts.
Low-Rise Building with 1-3 stories.
Design Level: Approximate Basis: UBC Seismic Zone 0, NEHRP Map Area 1.
Pre-1941 construction in all other UBC and NEHRP areas.
Pre-Code damage functions are appropriate for modeling older buildings that were not designed for earthquake load, regardless of where they are located in the United States.
Suggested Block Size: 1 EA (round up to integer quantity)