[STRUCTURAL DESIGN SOFTWARE]sjalalim/Resources/5/Manual.pdfInput from SAP2000: The program receives...

2014

Pedrum Jalali

[STRUCTURAL DESIGN SOFTWARE] This document explains the structural design program implemented in VB.net

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Contents What is it? ..................................................................................................................................................... 3

Features: ....................................................................................................................................................... 3

Input from SAP2000: ................................................................................................................................. 3

Design: ...................................................................................................................................................... 3

Output: ...................................................................................................................................................... 3

How does it work? ........................................................................................................................................ 4

How does it work? ........................................................................................................................................ 5

Step 1: ....................................................................................................................................................... 5

Step 2: ....................................................................................................................................................... 6

Structure Data: ...................................................................................................................................... 7

Analysis Output Folder: ......................................................................................................................... 7

Structure Object File: ............................................................................................................................ 7

Sap Output Units: .................................................................................................................................. 7

Program Output Units: .......................................................................................................................... 7

Get Structure Data: ............................................................................................................................... 7

Design:................................................................................................................................................... 7

Step 3: ....................................................................................................................................................... 7

Main: ..................................................................................................................................................... 8

Max Results: ........................................................................................................................................ 11

Reinforcement Sheets: ........................................................................................................................ 12

Object Model: ............................................................................................................................................. 17

GeneralStructure: ................................................................................................................................... 17

Joint: ........................................................................................................................................................ 17

Members: ............................................................................................................................................ 17

Functions: ................................................................................................................................................ 17

Area: ............................................................................................................................................................ 18

Members: ............................................................................................................................................ 18

Functions: ................................................................................................................................................ 18

Properties: ............................................................................................................................................... 18

Shear Wall: .................................................................................................................................................. 19

Members: ............................................................................................................................................ 20

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Functions: ................................................................................................................................................ 20

Properties: ............................................................................................................................................... 21

Section ........................................................................................................................................................ 21

Members: ............................................................................................................................................ 21

Functions: ................................................................................................................................................ 22

Properties: ............................................................................................................................................... 22

RectangularSection: .................................................................................................................................... 22

Functions: ................................................................................................................................................ 23

CircularSection: ........................................................................................................................................... 23

Functions: ................................................................................................................................................ 23

Element ....................................................................................................................................................... 23

Members: ............................................................................................................................................ 28

Functions: ................................................................................................................................................ 30

Properties: ............................................................................................................................................... 31

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What is it? The main functionality of this software is to design reinforced concrete beams and columns. The

software was written in VB.Net using the SAP2000 Open API.

The reasons for designing this software:

1. Differences between the available specification in SAP2000 and that of the Iranian specification

2. There are no built in functionality in SAP2000 for designing shear walls

3. Possible errors in SAP2000 for shear design of columns

4. Provides reinforcement curves in excel which will aid detailers in determining cutoff points for

longitudinal rebars.

5. Sometime several models are required for the same structure, such as cases when shear walls

are present. The program has the ability to combine the results of all these models.

Features:

Input from SAP2000: The program receives its input from exported data of Sap2000. Therefor it requires very little input form

the user:

Detects sections associated with each element

Detects if different elements are part of the same cast unit beam or column.

Detects if an area object is a slab or shear wall

Can detect which shear wall each area object is associated with

The input can come from multiple SAP2000 files. This is specially useful when shear walls are

present and multiple models are required for the same structure.

Design: Shear design

Torsional design

Combines longitudinal reinforcement from torsional and moment design

Combines transverse reinforcement from shear and torsional design

Redistributes moment forces in shear walls to side columns

Shear wall design

Output: Provides an easy to understand output in an excel workbook for further detailing

Provides charts displaying the required reinforcement along the length of the cast unit column

or beam.

The output excel workbook is created in a way that users can easily input rebar diameters and

the charts will be updated.

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How does it work? 1. The user creates a SAP2000 model of the structure and runs the analysis

2. The analysis results are then exported to an excel workbook.

3. The program reads the data from the excel file and performs the analysis.

4. Results are printed in an excel workbook

5. Users will have the chance to view the results in the output workbook. If the dimensions are not

adequate the user will need to modify the model and run results again.

Create a model

in Sap2000

Export the Analysis Results to

an Excel Workbook

Run the

program

Results

Ok?

Continue to

Detailing

Yes

No

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How does it work?

Step 1: The user creates the model of the structure in SAP 2000. After running the analysis he must export the

results into an Excel workbook (figure 1).1

Figure 1 Sap model

1 However a new version implemented later included the option for the program to directly read the models data

using the SAP2000 Open API

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Step 2: Start the program. The user form below will appear (figure 2):

Figure 2 Main Interface

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Structure Data:

This is where the program will find the excel file exported from SAP2000 with the structure data:

Joint coordinates

Frame sections

Section assignments

Frame connectivity

Area sections

Area connectivity

....

Analysis Output Folder:

This is where the program will find the excel files exported from SAP2000 with the analysis results:

Area forces

Element forces

....

Structure Object File:

This is where the program will store the object file associated with the structure

Sap Output Units:

The units used in the exported file form SAP2000

Program Output Units:

The units used in the output file from the program

Get Structure Data:

If this field is unchecked the structural properties (i.e. joint coordinates, sections, section assignments

...) will be read form the structure object file saved from the last session. If it’s checked it will be read

from the exported data from SAP2000. This was mainly used for debugging the program. As reading

structure data would take a long time, it would greatly speed testing.

Design:

If this is checked the beams and columns of the structure will be designed. If unchecked the previous

sessions design values will be read.

Step 3: After pressing the Run button, the program will perform the requested operations and the user will be

left with an Excel workbook (figure 3):

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Figure 3 Output, Main Sheet

The workbook has several sheets.

Main:

This sheet displays the most important output data. If a section isn’t sufficient or fails to meet one or

more design criterions the cells will be colored red (figure 3). If a section requires a high amount of

reinforcement that isn’t practical to construct, it will be colored yellow.

This sheet contains information about each station in each element for each load cases of all models

used in the analysis.

Columns AH , AI and AJ display the amount reinforcement required. The data bars give the user an idea

of how heavily reinforced the section is going to be.

The different columns in this sheet have been explained below:

ID: The label associated with the section in SAP2000

Station: The station the results are being displayed for

X1: The X coordinate of Joint I of the element

Y1: The Y coordinate of joint I of the element

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Z1: The Z coordinate of joint I of the element

X2: The X coordinate of Joint J of the element

Y2: The Y coordinate of joint J of the element

Z2: The Z coordinate of joint J of the element

C/B: Determines if the section is associated with a Beam or Column

H: The height of the section

B: The width of the section

D: The effective Height of the section

DPrime: The distance from the top reinforcements to the top of the section

Combination: The load combination the results are being displayed for

P: The axial force at the section for the current load combination

M2: The Moment about local axis 2 at the section for the current load

M3: The Moment about local axis 3 at the section for the current load

V2: the shear in the 2 direction at the section for the current load

V3: The shear in the 3 direction at the section for the current load

T: The torsion at the current section for the current load.

Bottom Rho: The amount of reinforcement steel required at the bottom of the section (Beams only)

Top Rho: The amount of reinforcement steel required at the top of the section (Beams only).

Column Rho: The amount of reinforcement steel required for columns.

P Adj: Shear walls are accompanied by 2 columns on their sides. The shear wall is designed for the shear

force while the columns are designed for the moment. The axial forces in the shear wall are assigned to

the columns. The value in this column displays the axial force In the column after adding the moment

forces from the shear walls.

Check 14-15-1: This is a check in the Iranian design specifications. It ensures that beams have a ductile

failure.

As_Sn2: Determines the amount of shear reinforcement required in the local 2-2 direction.

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As_Sn3: Determines the amount of shear reinforcement required in the local 3-3 direction.

As_Sn_T: Determines the amount of Torsional reinforcement.

As_L: The amount of longitudinal reinforcement required to accompany the torsional transverse

reinforcement.

As_Sn_VT: The total amount of transverse reinforcement require (Shear + Torsion).

Check 15-22: A check in the Iranian specifications. Checks if shear reinforcement does not exceed the

maximum value for the section.

Tcr: Cracked torsional resistance for the section

Rho_bottom_Total: The total longitudinal reinforcement required (Moment + Axial + Torsional

Longitudinal). Data bars are created for this column to give users an idea of how heavily reinforced the

section is (Beams only).

Rho_Top_Total: The total longitudinal reinforcement required (Moment + Axial + Torsional


section is (Beams only).

Rho_Column_Total: The total longitudinal reinforcement required (Moment + Axial + Torsional


section is (Columns only).

Check23_3_2_1_1_A and Check23_3_2_1_1_B: Checks in the Iranian specification for reinforced

concrete in seismic regions. It checks the dimensions of the concrete elements.

IsRec: Determines if the element is rectangular or circular

Warning: Determines if a warning is associated with this row or now

Error: Determines if an Error is associated with this row or not.

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Max Results:

The main sheet displays results for each section for each load case. The max results sheet on the other

hand displays the maximum amount of reinforcement based on the all the different load cases (figure

4).

Figure 4 Output, Max Results

Columns A~L are similar to the Main sheet.

Bottom Rho: The amount of longitudinal reinforcement required at the bottom of the section for all the

load cases (beams only).

Top Rho: The amount of longitudinal reinforcement required at the top of the section for all the load

cases (beams only).

Column Rho: The amount of longitudinal reinforcement required at the top of the section for all the

load cases (Columns only).

Pos Res: The amount of Positive moment resistance at the section (Beams only).

Neg Res: The amount of negative moment resistance at the section (Beams only).

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Seis Mod Rho Bot, and Seis Mod Rho Top: This is the modified bottom longitudinal reinforcement at the

section. The iraninan specification puts upper and lower limits on the amount of moment resistance

different sections of beam elements can have relative to each other in seismic regions. This is the

modified longitudinal reinforcement to account for it.

Reinforcement Sheets:

In the end the user will be provided by sets of sheets with required reinforcement for beams and

columns (Figure 5).

Figure 5 Output, Required Longitudinal Reinforcement

A single reinforced concrete beam might be modeled using several different elements in SAP2000. The

program automatically determines if 2 different elements belong to the same cast unit element or not.

As you can see in figure (5) the program has automatically detected that elements 104, 1 and 6 are part

of the same cast unit beam, and it has also detected that element 104 precedes element 1 and element

1 precedes element 6.

In order to make construction easier the user might want to design several columns or elements using

the exact same details. As you can see in figure 6 the chart is plotted for 3 different cast unit beams.

The first set is for the beam which consists of the elements 104, 1, 10,.... The second set is for the beam

which consists of the elements 121, 236, 237 ... and the last set is for the beam which consists of the

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elements 247, 248, 249,... The main interface of the program has a “Sets” button. By clicking this a user

form will open allowing the user to specify sets of beams. This way the program will plot these beam

and columns in the same chart (figure 8).

Figure 6 Ouptut, Required Transverse Reinforcement

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Figure 7 Elements in the Same Cast Unit

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Figure 8 User Interface for Selecting Cast Units in the Same Set

Below each chart is a section where you can specify rebars. The chart is automatically connected to

these cells. So as the user inputs values in these cells, the total value of the rebars will appear on the

chart (figure 9).

Also the required transverse reinforcement spacing is plotted a few rows down. This way the user can

make sure splice and cutoff locations are selected correctly (Figure 10).

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Figure 9 User selects rebar sizes to place in element. The sheet has been set in a way that these inputs will appear in the chart. This will greatly assist the user in the detailing stage.

Figure 10 Distribution of required transverse reinfrocement

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Object Model:

GeneralStructure: The main class used in this program is the GeneralStructure class. Below you can see some of the most

important members of this class. This class contains all the information related to the structure.

Joint: This class represents joints in the SAP2000 model. It contains information regarding the coordinates of

the joint and also the connecting elements to the joint.

Members:

Name Type Description

X Double X coordinate value

Y Double Y coordinate value

Z Double Z coordinate value

ID Integer Joint Label in Sap2000

ConnectedElements List (of Element) A list of all the elements connecting to this joint

Functions:


New Sub Class Constructor

Get Data Shared Function Receives as input a reference to an excel worksheet with the joint data and an empty list of joint objects. It retrieves the required data from the excel worksheet

Gen

eral

Stru

ctu

re

List (of ShearWall)

List (of Joint)

List (of Element)

List (of SectionType)

List (of Longitudinal)

List (of Area)

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and assigns it to the list of joint objects.

Get Joint Shared function Receives as input an ID and a list of joint objects. It returns the associated joint object.

Area: This class represents area object in the SAP2000 model. It contains the following information regarding

the area elements:

Connectivity

Direction

Forces

Type

...

Members:


Joint1 Joint Connected joint #1





Functions:



Get Data Shared Function as List (of Area)

Receives as input a reference to an excel worksheet with the joint data and an empty list of joint objects. It retrieves the required data from the excel worksheet

and assigns it to the list of joint objects.

SetArea_Forces Shared Sub Receives as input a list of areas and a reference to an Excel worksheet with the area forces. The function

assigns the forces from the excel sheet to the areas.

Properties:


Dir Readonly as Area.DirEnum

Returns the plane the area element is located in XY, XZ or YZ

IsWall

Readonly as boolean

Returns true if the area is associated with a shear wall, and false if the area is associated with a slab or the

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foundation.

Shear Wall: This class represents the shear wall in the structure. Note that SAP2000 cannot detect if an area object is

shear wall, slab, foundation, ...

Based on the output provided from SAP2000 the program automatically detects which areas are

associated with a shear wall. It then groups the areas into the different shear walls. It is assumed each

story has a separate shear wall. In the figure below you can see the sap model with the area objects. You

can see how the program has interpreted the different area objects:

Figure 11 Shear walls in SAP2000 model

Asides from determining the areas associated with the shear wall the class also determines the end

columns attached to the shear wall. This is required in the design process of the shear wall and the end

columns. The axial forces calculated in the shear wall are redistributed to the end columns.

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Figure 12 SAP2000 doesn't have built in functionality for designing shear walls. The programs designs shear walls using the P T method. The forces applied to the areas associated to the shear wall are coupled into 2 axial forces at the end columns. The shear wall is designed for the shear while the columns are designed for the axial forces.

The shear wall is only designed for the shear forces.

Members:


Areas List (of Area) A list of area objects associated with the shear wall

ShearWallDir Area.DirEnum The plane the shear wall Is located in. XZ or YZ.

ColumnI Element End column

ColumnJ Element End column


Functions:



GetWalls Shared Function as List(of

ShearWall)

Receives as input a list of area objects, a list of element objects and a list of story heights. It then determines which areas are associated with which shear walls. In

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the end it returns a list of shear walls.

RedistForces2Columns Shared Sub Redistributes the axial forces in the shear walls to the end columns

Properties:


Length Readonly as double

Returns the horizontal length of the shear wall

Section This class represents the frame sections. It contains information regarding the element sections such as:

Material property

Section cross sectional dimensions

....

The section class itself is an abstract class, which is derived by 2 concrete classes:

RectangularSection

CircularSecton

Members:


Eps_U Const Double The final compressive strain in concrete

Fc Const Double The 28 day compressive stress of concrete

Fy Const Double Yield stress of steel

Phi_C Const Double Margin of safety used for the concrete in the design

process

Phi_s Const Double Margin of safety used for the steel in the design

Section

RectangularSection CircularSection

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process

Es Const Double Steel modulus of elasticity

Alpha1 Double Multiplier used in concrete design

Beta1 Double Multiplier used in concrete design

Name String Name of section

H Double Cross section dimension

B Double Cross section dimension

D Double Distance from top fiber to the tension rebars centroid (or from the bottom fiber to the compression rebars

centroid)

Dprime Double Distance from top fiber to the compression rebars centroid (or from the bottom fiber to the tension

rebars centroid)

Cover Double Tie cover distance

TieDiameter Double Tie diameter

IsDoubleLayer Double Determines if rebars are in 2 layers or in a single layer.

This is used to calculate the value D and Dprime.

Functions:



GetSectionData Shared Function as List

(of Section) Receives as input reference to the worksheets with the

section data. Returns a list of sections.

Properties:


RX MustOverride Readonly

Property as Double Section’s Radius of gyration about the X axis

RY MustOverride Readonly Property as Double

Section’s Radius of gyration about the y axis

RectangularSection: This class represents the frame sections associated with rectangular frame elements. The class is derived

from the base class Section.

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Functions:



RX Overrides Readonly Property

as Double Section’s Radius of gyration about the X axis

RY Overrides Readonly Property

as Double Section’s Radius of gyration about the y axis

CircularSection: This class represents the frame sections associated with circular frame elements. The class is derived

from the base class Section.

Functions:



RX Overrides Readonly Property

as Double Section’s Radius of gyration about the X axis

RY Overrides Readonly Property

as Double Section’s Radius of gyration about the y axis

Element This class represents the different frame elements in the structure sections. It contains element specific

information such as:

Element ID

Forces in the element

Design Results

Element Stations

Start and end joints

The section class itself is an abstract class, which is derived by 2 concrete classes:

RectangularElement

CircularElement

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Stations Used for Longitudinal Column Design:

The design process if preformed using the output forces obtained from SAP2000. In the figure below you

can see sample output forces from an analysis performed in SAP2000.

Figure 13 Output stations

I can be seen from the figure above that columns G to K contain the output forces for each station and

load case. The stations and load cases are specified in column B and C. It can be seen that for each

station we have multiple load cases. Due to the fact that column design uses 2 parameters (M and P) it

would not be correct to design based on the envelope. Design must be performed considering each load

case separately.

Element

RectangularElement CircularElement

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After calculating the reinforcement required at each station of the column for each load case the

program calculates the maximum reinforcement required at each station considering all the load cases.

Load Case 1

Station 1

Station 2

Station 3

Design Reinforcement



Load Case 2

Station 1

Station 2

Station 3




Load Case 3

Station 1

Station 2

Station 3




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Longitudinal Reinforcement:

Longitudinal reinforcement comes from 3 sources:

1. Moment-Force design for columns and Moment design for beams

2. Longitudinal reinforcement due to torsional design.

3. Axial force for columns next to shear walls.

Station 1

Reinforcement designed based on load case 1



Max Reinforcement

Station 2




Max Reinforcement

Station 3




Max Reinforcement

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Although SAP2000 does give the first 2 amounts of required rebar, it does not take into account the axial

force to due shear wall moment. The program manually calculates this values. Note that for each load

case and each station of an element there will be a different combination of loads. For each possible

load case at each station of each element next to a shear wall the program creates a separate auxiliary

model in SAP2000. These models have a length of 1m and with a fixed end at the bottom with the

calculated loads applied at the other end. The total number of models would be:

This would result in a very large number of models. Therefore all the models where combined into one

single model.

Transverse Reinforcement:

Due to the difference between the Iranian concrete specification and those available in SAP2000 and

also a possible error in the way SAP2000 designed transverse reinforcement, it was decided to leave the

calculation of the transverse shear entirely to the program.

The amount of transverse reinforcement depends on 2 factors:

1. Transverse reinforcement due to shear

2. Transverse reinforcement due to torsion

Total Longitudinal

Reinforcements

Longitudinal Reinforcement

Due to Torsional Deisng

Axial Force for Columns Next to

Shear Walls

Longitudinal Reinforcement

Due to M-P Design

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Figure 14 At each output station of each element for each load case there will be a combination of forces. In order to calculate the required longitudinal reinforcement at this location a new auxiliary model is generated and is used to calculate the required reinforcement.

The analysis is run and the longitudinal reinforcement is calculated. The program then searches through

the calculated reinforcements for each station and returns the maximum value obtained.

Members:


ID Integer Element ID defined by SAP2000

Forces List (of Forces) Forces in the element. These values are obtained from

the analysis run in SAP2000

P_Adj List (of double)

In the design of the shear walls, the axial forces in the walls are redistributed and added to the axial force in the side columns. This is the adjusted axial force in the

columns adjacent to the shear wall.

Rho_Column List (of double) The required reinforcement at each station for each

load case for column elements

Rho_Columnax List (of double) The maximum required reinforcement at each station

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considering all load cases

As_Sn_T List (of double) The ratio of transverse steel to its spacing at each

station for each load case for torsional design

As_L List (of double) The required longitudinal steel at each station due to

torsional design

As_Sn_VT List (of double) The ratio of transverse steel to its spacing at each

station for each load case for torsional and shear design

Tcr List (of double) Cracked torsional resistance at each station

Check14_5_1 List (of

OKNGENUM)

A check required by the Iranian specification to prevent brittle failure in beam elements. This variable is the

result of this check at each station

Check15_22 List (of

OKNGENUM)

A check required by the Iranian specifications to limit the maximum transverse reinforcement. This variable is

the result of this check at each station

Stations List (of double) A list of stations for the element. The values in this list

are not unique. For each load case the stations are repeated.

Uniquestation List (of double) A list of stations for the element.

C_NA List (of double) The neutral axis at the different stations

As_Sn2 List (of double) The ratio of transverse steel to its spacing at each

station for each load case shear design in the local 2-2 direction

As_Sn3 Double The ratio of transverse steel to its spacing at each

station for each load case shear design in the local 3-3 direction

JointI Joint The joint object at the start of the element

JointJ Joint The joint object at the end of the element

Rho_bottom List (of double) The required longitudinal reinforcement at the bottom of the section for beam elements This is the calculated

reinforcement for each load case.

Rho_Top List (of double) The required longitudinal reinforcement at the top of the section for beam elements. This is the calculated

reinforcement for each load case.

Rho_bottomMax List (of double) The required longitudinal reinforcement at the bottom of the section for beam elements considering all load

cases.

Rho_TopMax List (of double) The required longitudinal reinforcement at the top of

the section for beam elements considering all load cases.

IsWallEnd Boolean Determines if the element is a column at the end of a

shear wall. This is used to determine whether the adjustment of the axial force is necessary or not.

Check23_3_2_1_1_A List (of

OKNGENUM)

A check required by the Iranian specification for concrete frames located in high seismic locations that

limits height to width ratio of the section.

Check23_3_2_1_1_B List (of A check required by the Iranian specification for

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OKNGENUM) concrete frames located in high seismic locations that limits the unsupported length of the element to its

height

MP List (of Double) The positive moment resistance of the element at

different stations along its length

MN List (of Double) The negative moment resistance of the element at

different stations along its length

Rho_TopMaxSMod List (of Double)

One of the requirements for concrete frames in seismic regions is that the moment resistance at the different

parts of the section must not be smaller than one third of that at the supports. This list accounts for this

change in reinforcement.

Rho_BottomMaxSMod List (of Double)

One of the requirements for concrete frames in seismic regions is that the moment resistance at the different

parts of the section must not be smaller than one third of that at the supports. This list accounts for this

change in reinforcement.

As_Sn_VT_Max List (of Double) The maximum amount of transverse reinforcement

required considering torsion and shear

Functions:



GetElementData Shared Function as

List (of Element) Receives as input reference to the worksheets with

the element data. Returns a list of elements.

RemoveDuplicateStations Sub

In the exported excel files there will be one stations listed for each load case for a single

element. This function removes all duplicates and only keep s the unique stations

SetForces Sub Receives as input reference to the worksheet with the element force data and sets the forces for each

station of each element.

Design_VT Sub Calculates the shear and torsion reinforcement of

the Element

SetRebarColumns Sub

Receives as input reference to the worksheet with calculated column reinforcements and sets the

reinforcements for each station of each of those elements.

SetRebarColumns Sub

Receives as input reference to the worksheet with calculated beam reinforcements and sets the

reinforcements for each station of each of those elements.

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Properties:


RX MustOverride Readonly

Property as Double Section’s Radius of gyration about the X axis

RY MustOverride Readonly Property as Double

Section’s Radius of gyration about the y axis

[STRUCTURAL DESIGN SOFTWARE]sjalalim/Resources/5/Manual.pdfInput from SAP2000: The program receives...

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