LF.URM - Unreinforced Masonry Bearing Walls¶
The following models are available:
LF.URM.L.LC | Lifeline Facilities, Unreinforced Masonry Bearing Walls, Low-Rise, Low-Code
Lifeline Facility damage functions are expressed in terms of an equivalent value of PGA for efficient evaluation of buildings that are components of utility and transportation systems. Only structural damage functions are developed based on PGA, since structural damage is considered the most appropriate measure of damage for utility and transportation system facilities. Median values of equivalent-PGA fragility curves are based on median values of spectral displacement of the damage state of interest and an assumed demand spectrum shape that relates spectral response to PGA. As such, median values of equivalent PGA are very sensitive to the shape assumed for the demand spectrum. Spectrum shape is influenced by earthquake source (i.e., WUS vs. CEUS attenuation functions), earthquake magnitude (e.g., large vs. small magnitude events), distance from source to site, site conditions (e.g., soil vs. rock), and effective damping, which varies based on building properties and earthquake duration (e.g., short, moderate, or long duration). These fragility curves were developed for a single set of spectrum shape factors (a reference spectrum), and a formula is provided for modifying damage state medians to approximate other spectrum shapes. The reference spectrum represents ground shaking of a large magnitude (i.e., M7.0) western United States (WUS) earthquake for soil sites (e.g., Site Class D) at site-to-source distances of 15 km or greater.
Structural System: These buildings include structural elements that vary depending on the building’s age and, to a lesser extent, its geographic location. In buildings built before 1900, the majority of floor and roof construction consists of wood sheathing supported by wood framing. In large multistory buildings, the floors are cast- in-place concrete supported by the unreinforced masonry walls and/or steel or concrete interior framing. In unreinforced masonry constructed built after 1950 outside California, wood floors usually have plywood rather than board sheathing. In regions of lower seismicity, buildings of this type constructed more recently can include floor and roof framing that consists of metal deck and concrete fill supported by steel framing elements. The perimeter walls, and possibly some interior walls, are unreinforced masonry. The walls may or may not be anchored to the diaphragms. Ties between the walls and diaphragms are more common for the bearing walls than for walls that are parallel to the floor framing. Roof ties are usually less common and more erratically spaced than those at the floor levels. Interior partitions that interconnect the floors and roof can reduce diaphragm displacements.
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)
LF.URM.L.PC | Lifeline Facilities, Unreinforced Masonry Bearing Walls, Low-Rise, Pre-Code
Lifeline Facility damage functions are expressed in terms of an equivalent value of PGA for efficient evaluation of buildings that are components of utility and transportation systems. Only structural damage functions are developed based on PGA, since structural damage is considered the most appropriate measure of damage for utility and transportation system facilities. Median values of equivalent-PGA fragility curves are based on median values of spectral displacement of the damage state of interest and an assumed demand spectrum shape that relates spectral response to PGA. As such, median values of equivalent PGA are very sensitive to the shape assumed for the demand spectrum. Spectrum shape is influenced by earthquake source (i.e., WUS vs. CEUS attenuation functions), earthquake magnitude (e.g., large vs. small magnitude events), distance from source to site, site conditions (e.g., soil vs. rock), and effective damping, which varies based on building properties and earthquake duration (e.g., short, moderate, or long duration). These fragility curves were developed for a single set of spectrum shape factors (a reference spectrum), and a formula is provided for modifying damage state medians to approximate other spectrum shapes. The reference spectrum represents ground shaking of a large magnitude (i.e., M7.0) western United States (WUS) earthquake for soil sites (e.g., Site Class D) at site-to-source distances of 15 km or greater.
Structural System: These buildings include structural elements that vary depending on the building’s age and, to a lesser extent, its geographic location. In buildings built before 1900, the majority of floor and roof construction consists of wood sheathing supported by wood framing. In large multistory buildings, the floors are cast- in-place concrete supported by the unreinforced masonry walls and/or steel or concrete interior framing. In unreinforced masonry constructed built after 1950 outside California, wood floors usually have plywood rather than board sheathing. In regions of lower seismicity, buildings of this type constructed more recently can include floor and roof framing that consists of metal deck and concrete fill supported by steel framing elements. The perimeter walls, and possibly some interior walls, are unreinforced masonry. The walls may or may not be anchored to the diaphragms. Ties between the walls and diaphragms are more common for the bearing walls than for walls that are parallel to the floor framing. Roof ties are usually less common and more erratically spaced than those at the floor levels. Interior partitions that interconnect the floors and roof can reduce diaphragm displacements.
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)
LF.URM.M.LC | Lifeline Facilities, Unreinforced Masonry Bearing Walls, Mid-Rise, Low-Code
Lifeline Facility damage functions are expressed in terms of an equivalent value of PGA for efficient evaluation of buildings that are components of utility and transportation systems. Only structural damage functions are developed based on PGA, since structural damage is considered the most appropriate measure of damage for utility and transportation system facilities. Median values of equivalent-PGA fragility curves are based on median values of spectral displacement of the damage state of interest and an assumed demand spectrum shape that relates spectral response to PGA. As such, median values of equivalent PGA are very sensitive to the shape assumed for the demand spectrum. Spectrum shape is influenced by earthquake source (i.e., WUS vs. CEUS attenuation functions), earthquake magnitude (e.g., large vs. small magnitude events), distance from source to site, site conditions (e.g., soil vs. rock), and effective damping, which varies based on building properties and earthquake duration (e.g., short, moderate, or long duration). These fragility curves were developed for a single set of spectrum shape factors (a reference spectrum), and a formula is provided for modifying damage state medians to approximate other spectrum shapes. The reference spectrum represents ground shaking of a large magnitude (i.e., M7.0) western United States (WUS) earthquake for soil sites (e.g., Site Class D) at site-to-source distances of 15 km or greater.
Structural System: These buildings include structural elements that vary depending on the building’s age and, to a lesser extent, its geographic location. In buildings built before 1900, the majority of floor and roof construction consists of wood sheathing supported by wood framing. In large multistory buildings, the floors are cast- in-place concrete supported by the unreinforced masonry walls and/or steel or concrete interior framing. In unreinforced masonry constructed built after 1950 outside California, wood floors usually have plywood rather than board sheathing. In regions of lower seismicity, buildings of this type constructed more recently can include floor and roof framing that consists of metal deck and concrete fill supported by steel framing elements. The perimeter walls, and possibly some interior walls, are unreinforced masonry. The walls may or may not be anchored to the diaphragms. Ties between the walls and diaphragms are more common for the bearing walls than for walls that are parallel to the floor framing. Roof ties are usually less common and more erratically spaced than those at the floor levels. Interior partitions that interconnect the floors and roof can reduce diaphragm displacements.
Mid-Rise Building with 4-7 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)
LF.URM.M.PC | Lifeline Facilities, Unreinforced Masonry Bearing Walls, Mid-Rise, Pre-Code
Lifeline Facility damage functions are expressed in terms of an equivalent value of PGA for efficient evaluation of buildings that are components of utility and transportation systems. Only structural damage functions are developed based on PGA, since structural damage is considered the most appropriate measure of damage for utility and transportation system facilities. Median values of equivalent-PGA fragility curves are based on median values of spectral displacement of the damage state of interest and an assumed demand spectrum shape that relates spectral response to PGA. As such, median values of equivalent PGA are very sensitive to the shape assumed for the demand spectrum. Spectrum shape is influenced by earthquake source (i.e., WUS vs. CEUS attenuation functions), earthquake magnitude (e.g., large vs. small magnitude events), distance from source to site, site conditions (e.g., soil vs. rock), and effective damping, which varies based on building properties and earthquake duration (e.g., short, moderate, or long duration). These fragility curves were developed for a single set of spectrum shape factors (a reference spectrum), and a formula is provided for modifying damage state medians to approximate other spectrum shapes. The reference spectrum represents ground shaking of a large magnitude (i.e., M7.0) western United States (WUS) earthquake for soil sites (e.g., Site Class D) at site-to-source distances of 15 km or greater.
Structural System: These buildings include structural elements that vary depending on the building’s age and, to a lesser extent, its geographic location. In buildings built before 1900, the majority of floor and roof construction consists of wood sheathing supported by wood framing. In large multistory buildings, the floors are cast- in-place concrete supported by the unreinforced masonry walls and/or steel or concrete interior framing. In unreinforced masonry constructed built after 1950 outside California, wood floors usually have plywood rather than board sheathing. In regions of lower seismicity, buildings of this type constructed more recently can include floor and roof framing that consists of metal deck and concrete fill supported by steel framing elements. The perimeter walls, and possibly some interior walls, are unreinforced masonry. The walls may or may not be anchored to the diaphragms. Ties between the walls and diaphragms are more common for the bearing walls than for walls that are parallel to the floor framing. Roof ties are usually less common and more erratically spaced than those at the floor levels. Interior partitions that interconnect the floors and roof can reduce diaphragm displacements.
Mid-Rise Building with 4-7 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)