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Masonry Lintel |
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Masonry Lintel |
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This module provides design analysis for concrete masonry lintels subject to vertical and lateral loads. Lintels can have fixed or pinned ends for most typical conditions, and the user can specify rebar sets within the depth of the lintel.
Vertical loads can be dead and live uniform and concentrated loads. You can have up to four loads of each type, and the uniform loads can be full or partial length.
The module provides analysis for both seismic and wind loads for each recalculation. You can specify seismic factors that apply to the lintel's weight and a wind load.
To allow the module to model different concrete block types, you can specify either lightweight or medium weight block, and additionally enter a lintel weight multiplication factor.
For both the vertical and lateral bending and shear directions, the module calculates allowable bending moments and shear stresses. Also, for both directions, actual moments and shears due to all entered loads are calculated. Final results consist of combined stress ratio calculations for all combinations or dead, live, seismic, and wind vertical and lateral moments and shears.
Unique Features
| • | This module calculates all vertical and lateral moments and shears and combines them for all possible stress ratios. This is a very thorough evaluation of combined stresses for seismic and wind design. |
| • | The module also provides the ability to modify the material weight, automatically reverse seismic and/or wind loadings, and model both fix-fix and pin-pin end fixity conditions. |
Assumptions & Limitations
When the lintel's fixity is set to Fixed, both vertical and lateral bending are considered fixed.
General Tab
This tab provides data entry for the lintel dimensions, material properties and lateral loads.
Clear Span and Lintel Depth are used to calculate the beam bending and shears.
Thickness is the nominal masonry thickness. The true thickness is determined from internal tables.
End Fixity controls whether the analysis will consider the lintel to be pinned or fixed. Pinned results in higher center span moments and is probably conservative, however fixed is closer to the true construction.
Calculate & Include Vertical Lintel Weight tells the module to calculate the lintel self-weight and add it as a uniform load across the full span.
Material Data defines the allowable stressed for masonry and reinforcing steel.
Wall Weight Multiplier allows the user to factor up or down the lintel self weight that is pulled from internal tables.
Block Type selects the density of the CMU used for self weight.
Lateral Loads allows you to specify wind and seismic loads that are applied horizontally and perpendicular to the span of the lintel. Seismic Weight factor is a multiplier applied to the lintel self weight to create a laterally applied uniform loads.
Reinforcing Tab
This tab allows you to specify the longitudinal reinforcing in the lintel.
Rebar Size
Enter the rebar size used for all longitudinal bar sets to be used in the lintel.
# Bars Each Face
Enter the number of rebars at each face of the wall for each bar set. In the example problem, only one #6 was used on each face for all three bar sets.
Rebar Distance from Top & Bottom of Lintel to Centerline of rebar group
Distance from the top and bottom of the lintel respectively to the center of area of the bar set. These distances will be used as d for vertical bending strength calculations.
# Bar Sets Vertically
Enter the number of bar sets in the lintel.
Bar Spacing
This is the clear distance between the bars on each face in a bar set. IT IS ASSUMED THAT THE BARS ARE CENTERED ALONG THE LINTEL VERTICAL CENTERLINE. d used for lateral bending strength calculations is calculated as: Spacing Between Bars + (Actual Thickness - Spacing Between Bars) / 2
Shear Reinforcement
When you click [Yes] you can specify the vertical shear reinforcement used in the lintel. The results will then reflect the allowable & actual shear stress ratios.
Vertical Load Tab
This tab allows you to specify point loads and distributed loads applied to the lintel.
Load Combinations Tab
This is the typical load combination tab used throughout the SEL. "LDF" is a Load Duration Factor that will be applied to allowable stresses and is only available for the ASD design method.
Output & Graphics Tabs
Results Tab
This tab summarizes the calculated moments, shears and combined stress ratios for the lintel.
Ratios for bending and shear are provided for both vertical and lateral load applications. There are no calculations for combined vertical & lateral stresses.
M & V Results Tab
This tab provides full details for all actual and allowable stresses for all load combinations.
Design Values Tab
This tab summarizes allowable stress calculations. When ASD is used, the tab looks like this:
And when LRFD is used, the tab looks like this:
Sketch Tab
