An accurate structural drawing is a most important task in executing any structure such as building structure. This is the expression of a structural design carried out by a structural design which followed at site. For this purpose, AutoCAD or similar drafting packages are widely used. Here authors made an attempt to customize the AutoCAD for automated drafting of structural member like continuous beam. The customization is carried out using Visual Basic for Application (VBA) code. In this program, only the schedule of bars, span of beam and width of column are to be supplied as input for the drafting purpose which eliminate manual errors completely. The continuous beam section along with complete details, bar curtailment dimensions etc. appears in AutoCAD which can be modified as required.

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Automated Drafting of R.C. Beam Using AutoCAD

S. K. Mahajan * R. S. Sonparote **

ABSTRACT

An accurate structural drawing is a most important task in executing any structure such as building

structure. This is the expression of a structural design carried out by a structural design which followed at

site. For this purpose, AutoCAD or similar drafting packages are widely used. Here authors made an

attempt to customize the AutoCAD for automated drafting of structural member like continuous beam.

The customization is carried out using Visual Basic for Application (VBA) code. In this program, only the

schedule of bars, span of beam and width of column are to be supplied as input for the drafting purpose

which eliminate manual errors completely. The continuous beam section along with complete details, bar

curtailment dimensions etc. appears in AutoCAD which can be modified as required.

INTRODUCTION

Now –a-days, computers are being widely used in the design and drafting of Reinforced Concrete

members. Various softwares have been developed for this purpose. Out of which many softwares gives

only final results and others gives both results and reinforcement sketches. Usually the sketches given

by such software is of fixed standard format. Individual structural designer could not change its format

as per his requirement. Therefore, drawing has to be change as per individual's requirement. When

structural designer gets only final results from the software or manual design then drawing has to be

prepared manually which is the tedious and time consuming work and also it may have many manual

errors which may result in serious mishaps. Therefore, there is a need of a program which can be easily

customized as per the individual's choice and easily available to everyone.

Earlier S.C. Chakrabarti and Rajeev Kr. Sharma ( ) developed a package for design and drafting of beams

using FORTRAN 77 and HPGL language for the drafting of beam sections (Longitudinal and cross section).

The package has been used extensively for in-house design and drafting of beams at the Central Building

Research Institute, Roorkee (CBRI).

For the computer aided drafting AutoCAD is widely used. Therefore, there is a need of a program which

can customize AutoCAD rather than independent package as all other drawings are prepared in

AutoCAD such as Layout plan, schedule, Notes etc.

AutoCAD customization can be divided into following two part.

1. Non-programming customization.

2. Programming customization.

*Assistant Professor , Kavikulguru Institute of Technology & Science, Ramtek.

** Assistant Professor, Visveswaraya National Institute of Technology , Nagpur

Non-programming customization consist of following

a. User interface customization by adding specific required toolbar, menu bar and pallets.

b. Creation of customized hatch.

c. Block library development.

d. Creation of customized line types and shape.

Programming customization consist of addition of users own commands to AutoCAD which will perform

the activities desired. Some of the examples of AutoCAD programming are as follows

a. Design and drafting automation.

b. Automatic drawing generation based on design calculation.

c. Automatic production drawing generation.

d. Automatic bill of material generation.

The main reason of customization is time saving and elimination of manual error. Time wasted on

repeated type of work can be saved and used for other more productive work, accurate output

generation and quick response to user's queries. Almost all activities that user do manually can perform

automatically through AutoCAD customization.

AutoCAD has given a free hand to developers to choose the tool they like most for AutoCAD

customization. Users can customize AutoCAD and produce good quality structural drawings etc. using

AutoLisp, Visual Lisp, VBA. For C and C++, objectARX is used. AutoCAD can be customized using .net

languages.

IS Code Provisions

The Various IS code provisions for the reinforcement detailing is given in IS 456: 2000 and Handbook on

concrete Reinforcement and detailing ( SP 34: 1987 ). A simplified curtailment rules for continuous beam

is shown in figure 1.

Note-I t Applicable lo continuous beams with approximately equal spans (not differing more than 15

percent) and subjected to predominantly U.D.L.. and designed without compression steel.

Figure 1. Simplified curtailment rules for continuous Beams

The simplified curtailment rules for simply supported beam is shown in figure 2

*In case partially restraint members, 35% of the reinforcement shall also be provided for negative

moment at the support and fully anchored.

Figure 2. Simplified Curtailment Rules for Simply Supported Beam

THE PROGRAM

An interactive and user friendly program is developed by using the VBA code in AutoCAD. Using VBA, the

AutoCAD can be customized as per the user's requirements. A AutoCAD software is necessary to use this

program. After opening the program in AutoCAD, an interactive graphics window(Form) is displayed on

the screen. The input values are to be entered in this window and these values can be easily edited.

User can save all the inputs in a file. The complete longitudinal section of beam is automatically drawn in

the AutoCAD window with all the necessary details. The drawing is made by using various layers like

dimension layer, text layer, outline layer etc. Now the drawing can be easily edit and modify by using

AutoCAD commands. The drawing can be save as in all formats supported by the AutoCAD by using

AutoCAD.

FUNCTIONING OF THE PROGRAM

For drafting purpose, the program is to be loaded in AutoCAD by using menu 'Tools' - 'Load Application'.

Now user has to enter the Number of spans available in the beam, select the End support condition i.e.

left and right end whether it is dead end or continuous, each Support width. After giving above data user

has to enter Beam Name, Width, Depth, Clear span, Bottom Reinforcement which includes number and

diameter of continuous and cut bar, Top Reinforcement which includes number and diameter of

continuous and Extra Top bar with respect to their span number. A typical input window is shown in

figure 3.

Now after giving all the inputs, user has to click on the 'Draw' button to plot the drawing. This action will

plot the drawing in the AutoCAD window as shown in figure 4. This drawing can be easily edited by using

AutoCAD drawing commands. As this drawing is plotted using different layers like Beam Outline,

Dimensions, Steel etc., editing becomes easy and fast. The drawing can be save in different format

supported by the AutoCAD.

Figure 3. Typical Input data screen

User can save the input data in a file by clicking the 'Save Data' button so that in future one can plot by

using this input data. User can also load the input data saved in the file by clicking the 'Open' button.

Figure 4. Screen Showing Plot of Beam.

CONCLUSION

The Visual Basic for Application (VBA) available in AutoCAD has been exploited to develop an interactive,

user friendly and menu driven program for the drafting of continuous/single beam reinforcement

detailing. This program can save the extra time required for drafting the detailing manually using

AutoCAD and without any error. The developed software offers a strong graphic support in the form of

reinforcement detailing. As the program uses the AutoCAD to plot the sketch, the user can be

immediately modify and save the drawing by using AutoCAD commands. The VBA tool is the inbuilt tool

available in the AutoCAD therefore separate Visual Basic Language compiler is not required. The

software developed can be easily modified for customization of AutoCAD for all other structural

component so that accurate and fast structural drawings can be prepared.

REFERENCE

1. Code of Practice for Plain and Reinforced Concrete, Bureau of Indian Standards, IS456:2000,

Manak Bhavan, New Delhi.

2. Handbook on Concrete Reinforcement and detailing, Bureau of Indian Standards, SP34:1987,

Manak Bhavan, New Delhi.

3. Chakrabarti, S.C. ; Sharma, R.K., A Software package for design and drafting of beams, The

Indian Concrete Journal, March 1994.

4. Joe Sutphin, AutoCAD 2006 VBA: A Programmer's Reference, Apress publication.

( Date : December 2009 )

ResearchGate has not been able to resolve any citations for this publication.

Handbook on Concrete Reinforcement and detailing

Handbook on Concrete Reinforcement and detailing, Bureau of Indian Standards, SP34:1987, Manak Bhavan, New Delhi.

A Software package for design and drafting of beams

  • S C Chakrabarti
  • R K Sharma

Chakrabarti, S.C. ; Sharma, R.K., A Software package for design and drafting of beams, The Indian Concrete Journal, March 1994.

AutoCAD 2006 VBA: A Programmer's Reference, Apress publication

  • Joe Sutphin

Joe Sutphin, AutoCAD 2006 VBA: A Programmer's Reference, Apress publication. ( Date : December 2009 )