This program provides design and analysis ability for masonry shear wall sections subject to in-plane lateral loads (parallel to their length). You can model a series of shear pier segments that will each carry a percentage of an applied lateral force based upon the relative rigidities of each segment.

 

A maximum of five shear piers may be specified, each with its own length, height, thickness, and fixity conditions. Also, each of these piers may have individual allowable stresses for conditions where higher strengths are required for specialized designs of highly stressed sections. A load duration factor can be entered for stress adjustments when the nature of loading changes.

 

The program automatically determines individual pier stiffness's and distributes an overall single applied lateral load to each pier. Unit shear forces, design shear forces, and bending moments in each pier are calculated and used to determine the required shear and end reinforcing.

 

 

Basic Usage

 

Unique Features

 

 

Example

The data entry for this example is shown in the screen captures that accompany the Data Entry Tabs and Results & Graphics Tabs sections to follow.

 

 

Data Entry Tabs

This set of tabs provides entries for all input in this calculation. While you are entering data and switching between these tabs you can view the desired resulting information on the tabs on the right-hand side of the screen (calculated values, sketches, diagrams, etc.). A recalculation is performed after any entry data is changed. After each data entry you can view the results on the right-hand set of tabs.

 

 

General Tab

 

 

Total Lateral Force

Enter the total lateral force, acting parallel to the piers, which will be distributed to each pier. Distribution is by relative rigidities.

 

Seismic Zone

Enter the UBC Seismic Zone.

 

Load Duration Factor

This factor will be applied to the f'm and Fs values to give the allowables to be used in the analysis.

 

Moduli: Em = f'm * (entry)

In masonry construction the value of Em (Elastic Modulus of the masonry) is calculated as a multiplier applied to f'm.  Enter that multiplier here.

 

Use Grouting at Face Shells Only?

This item tells the program whether to calculate equivalent solid thickness using just the face cells with grout in the bedding or that all block surfaces that mate with the next block above or below have a grout bed.

 

 

Shear Pier Data Tab

 

Pier Height

This value of pier height will be used to calculate the rigidity and bending moment of each pier. This should be measured in a direction perpendicular to the direction of applied lateral loads.

 

Pier Length

This length should be measured in a direction parallel to the applied lateral loads, and will be used to determine rigidity, unit shear, and d distances for calculating required shear and bending reinforcement.

 

Pier Thickness

This thickness will be used to modify the pier rigidity by a factor of thickness/12, to adjust deflections by considering wall thickness. It will also be used to determine the actual shear stresses within the wall. Enter nominal thicknesses.

 

j

Because most masonry shear piers are not long bending members but actually deep beams, we have allowed the user to enter a particular  j  factor to be used in determining the distance from maximum tension steel to center of gravity of compression stress block. The pier length will be multiplied by j to determine the d (depth) distance from extreme compression fiber to centerline of tension steel.

 

Fixity Type Code

Enter the fixity condition of each pier to be used in determining individual pier rigidities. Only Pinned-Fixed and Fixed-Fixed restraint conditions are allowed.

 

f'm

Enter the allowable masonry strength to be used in the analysis. The allowable bending and axial stresses calculated from F'm are outlined in a later section. If the user has chosen not to use special inspection, both allowable axial and bending stresses will be multiplied by ½.

 

Fs

Enter the allowable tension strength of the reinforcing to be used. This value will be used as entered to determine the interaction equations for the design being performed.

 

Special Inspection

In this location, enter a 1" to specify if special inspection will be used, therefore allowing full F'm based masonry stresses to be used. Entering a 0" specifies that special Inspection will not be performed, and a multiplier of ½ will be applied to F'm based allowable stresses.

 

Grouted Cell Spacing

This entry specifies the spacing at which the vertical cells are grouted, and controls the determination of equivalent solid thickness (recalled from an internal table).

 

 

Results & Graphics Tabs

This set of tabs provides the calculated values resulting from your input on the "Data Entry Tabs". Because a recalculation is performed with each data entry, the information on these tabs always reflects the accurate and current results, problem sketch, or stress/deflection diagram.

 

Results / Summary Tab

 

 

fv = V / (12 * EST * j * d)

This is the actual shear stress within each pier, considering the tributary applied force, length, j, and equivalent solid thickness.

 

Fv w/o Reinforcing

This is the code allowable shear stress for piers without reinforcing.

 

Fv with Reinforcing

This is the code allowable shear stress for piers with reinforcing.

 

Horiz. As Required

Reinforcing area required to take shear if the shear stress exceeds the Fv w/o Reinforcing value.

 

Moment

Calculated moment in the pier using the tributary pier force and pier height.

 

d to Tension As

This is equal to j times the pier length.

 

Bending As Required

Using the bending moment calculated above, an iteration process using actual j values is executed to determine the required bending reinforcement to be located at a distance of Pier Length - 8 inches.

 

Results / Analysis Data Tab

 

 

Height / Length

As an intermediate step in calculating the rigidity values, the two applicable height / length ratios are calculated.

 

Relative Deflection

This relative deflection will be used to determine the relative rigidities using standard equations.

 

Rigidity

The rigidity value of each individual pier is equal to the inverse of the stiffness.

The formulas are:

DEFL (FIXED) = P H3/(12 * Em) + 1.2 P H/(Ev * Area)

DEFL (PINNED) = P H3/(3 * Em) + 1.2 P H/(Ev * Area) Rigidity = 1/Deflection

 

Sum Rigidities

This equals the summation of the individual rigidities of all of the piers, and is used as the denominator in calculating the distribution coefficients to each individual pier.

 

% of Force per Pier

Represents the percent rigidity calculated for each pier, and will be multiplied by the Total Lateral Force to give the forces applied to each pier.

 

Shear per Pier

This value is simply the % Force Taken Per Pier * Lateral Load, and is the force taken by each pier for the analysis.

 

Relative Pier Deflection

Using the calculated pier stiffness, this is the deflection that the pier will experience due to the percentage load applied to that pier.

 

M/(V * Depth)

This intermediate calculation is used to determine the correct formulas used to obtain the allowable masonry shear stresses.

 

Em

Shear modulus; used as a component in the rigidity calculation

 

Ev

Shear modulus; used as a component in the rigidity calculation

 

 

 

Sketch Tab

This tab provides a sketch of the beam with loads and resulting values shown. Using the [Print Sketch] button will print the sketch in large scale on a single sheet of paper.

 

 

Printing Tab

This tab allows you to control which areas of the calculation to print. Checking a box will signal that the information described by the item will be printed. However, if there is no information in for a particular selection it will not be printed. So these checkboxes are best described as "If this particular area of the calculations contains data then print it".

 

 

 

 

Sample Printout