This module provides analysis and design for masonry beams and lintels subject to vertical and lateral loads. Beams can have fixed or pinned ends for most typical conditions, and the user can specify rebar sets within the depth of the beam.
Vertical loads can be dead and live uniform and concentrated loads. A beam can have up to four loads of each type, and the uniform loads can be full or partial length.
The module also provides analysis for both seismic and wind loads. Wind load can be specified as well as seismic factors that apply to the beam's weight.
To allow the module to model different masonry block types, you can specify either lightweight or medium weight block, and additionally enter a self-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.
•This module calculates all vertical and lateral moments and shears and combines them for all possible stress ratios. This provides a 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 beam's fixity is set to Fixed, both vertical and lateral bending are considered fixed.
General & Materials
This tab provides data entry for the beam dimensions, material properties and lateral loads.
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.
Beam is Fully Braced dictates whether the module checks the unbraced length or not.
Auto add beam self weight as Dead Load tells the module to calculate the member self-weight and add it as a uniform vertical load across the full span.
Calculate Shear at d/2 from edge controls the critical location for the shear check.
Material Data defines the allowable stresses for masonry and reinforcing steel.
Wall Weight Multiplier allows the user to factor the lintel self-weight that is pulled from internal tables.
Block Type selects the density of the CMU used for self-weight.
Modulus of Rupture collects MOR for masonry.
Design Method provides the option to select Allowable Stress Design or Strength Design.
This tab allows you to specify the longitudinal reinforcing in the beam.
Note: All longitudinal reinforcing bars are assumed to be fully developed. No attempt is made to compare the moment diagram with a longitudinal rebar development diagram, so engineering judgment should be applied in situations where end fixity is assumed and/or where heavy concentrated loads cause significant moments at locations close to the development zone of the provided reinforcement.
Enter the rebar size used for all longitudinal bar sets to be used in the lintel.
Bars Each Face (checkbox)
Selected implies that the lintel is reinforced with two layers of reinforcing separated by the value specified in the "Bar Spacing" input.
Deselected implies that the lintel is reinforced with one layer of reinforcing located at the middle of the width of the lintel.
The beam below DOES have bars each face:
The beam below does NOT have bars each face:
This is the clear distance between the bars on each face in a bar set. It is assumed that the bar set is centered within the width of the lintel. The value of "d" used for lateral bending strength calculations is calculated as: Actual Masonry Thickness - (Actual Masonry Thickness - Bar Spacing) / 2
# Bars Each Location
Enter the number of individual rebars to consider at each reinforced location.
The beam below has one bar at each reinforced location:
The beam below has three bars at each reinforced location:
Rebar Distance from Top & Bottom of Beam to Centerline of rebar group
Distance from the top and bottom of the member to the center of area of the respective bar set. These distances will be used as "d" for vertical bending strength calculations.
# Bar Sets
Enter the number of bar sets in the lintel. A value of one indicates that the lintel has bottom reinforcing only.
The beam below has one bar set:
The beam below has two bar sets:
The beam below has three bar sets:
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.
This tab allows you to specify all loads applied to the lintel. The Point Loads and Distributed Loads categories are assumed to be vertical loads. The Lateral Loads category allows you to specify wind and seismic loads that are applied horizontally, 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 load.
This is the typical load combination tab used throughout SEL.
Output & Graphics Tabs
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 as well as an SRSS calculation for combined vertical & lateral stresses from the controlling load combination.
M & V Results
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 SD is used, the tab looks like this:
2D Sketch (Span & Loads subtab)
2D Sketch (Cross Section subtab)