CIVL1014 – Surveying and Drawing DRAWING LECTURE

Part 1: Basic Drawing Skills

THE UNIVERSITY OF HONG KONGDr. Ray Su

Department of Civil Engineering

(office: HW 6(office: HW 6--6, Tel. no.: 2859 26486, Tel. no.: 2859 2648Email: Email: klsu@hkucc.hku.hkklsu@hkucc.hku.hk))

Tutor: Dr. YP Huang (HW 514B, Tel. 852-2859 7067 , email: yhuanga@hkucc.hku.hk)

Kadoorie

Biological Sciences Building

The framing plan

Kadoorie

Biological Sciences Building

The RC details

The border

Informationpanel

Title block

General Information•

The course does not have a written examination. In-

course assessment is based on drawing assignments.•

The aim of this course is to familiarize the students with the techniques for reading and production

of

drawings. •

An engineer is not expected

to be a drawing

technician but he/she should be able to make

a neat drawing if required. It is important that an engineer should know how to communicate his/her design to the project team with drawings.

•

Engineering drawing is a graphical language which is used by engineers for communication. In order that an engineering drawing can be read and properly interpreted by engineers and other members involved in a project, some common practices, conventions and standards

should be observed.

General Information•

Lecture is devised to teach the students to understand what a drawing is; how it is produced

and

what it is used for.•

Students will be making drawings of their own on framing plans and details of reinforced concrete and steel structures.

•

Drawings prepared on tracing papers will be printed through arrangements by Department. The costs for printing will be borne by students. During the semester, all drawings will be returned to students after marking by tutors.

•

The submission of assignments should adhere strictly to the time schedule. Any late submission will be penalized by deduction of marks.

General InformationTentative schedule of this semester

Assignments 1 & 2 and 3 & 4 are submitted on 4 Nov and 25 Nov respectively

Thursday (3:00-4:55pm) Friday (3:00-3:55pm)

1 Sep 2 Sep

8 Sep 9 Sep

15 Sep 16 Sep

22 Sep 23 Sep

29 Sep Cancelled due to Nesat 30 Sep Engg. Drawing (at MWT1)

6 Oct Engg. Drawing (at MWT1) 7 Oct Engg. Drawing (at HW232)

13 Oct Engg. Drawing (at MWT1) 14 Oct Engg. Drawing (at HW232)

18 Oct Make-up Lecture from 10am to 1pm (Tuesday) at MWT1

21 Oct Reading week

27 Oct Engg. Drawing (at MWT1) 28 Oct Cancelled due to Open Day

3 Nov Engg. Drawing (at MWT1) 4 Nov Engg. Drawing (at HW232)

10 Nov Engg. Drawing (at MWT1) 11 Nov Engg. Drawing (at HW232)

17 Nov 18 Nov

24 Nov 25 Nov

Figure 1. Relationship between the principal members of a project development group

The design team The design team communicates by communicates by means of means of drawings and drawings and letters rather letters rather than design than design calculationscalculations

Why drawings are important for Engineers?

•

Design calculations

vs

Drawings•

In the coming years, engineering drawing is directly useful for surveying part

and the courses ED&C

and

FYP, and indirectly useful for T&D.•

After graduation, sketching skills can help you to (i) develop preliminary engineering schemes, (ii) prepare sketches

to instruct draftsmen to draw the formal

drawings (using AutoCAD), (iii) communicate with Client, Architects, Contractors, Engineers in other

fields, QS, Planners , and (iv) sit for the professional examinations.

Hand drawings vs

CAD drawings

Hand drawings CAD drawings

Sketches –

by engineers Detailed drawings –

by draftsmen

Paper & pencils Computers & plotters

Faster for complicated dwgs Faster for repeated & simple dwgs

Not good for amendments Convenient for amendments

Good for presenting ideas in consultancy meetings, professional examinations

Good for detailed design, formal submission, more accurate, usually higher quality and can link up with computer programs

Not good for filing Easier for filing

Drawing Sheets

•

Tracing paper is to be used and 85g/m2

quality is recommended. The size should be A1 (841mm×594mm).

Designation Size (mm X mm)

A0 841X1189

A1 594X841

A2 420X594

A3 297X420

A4 210X297 Drawing sheet sizes

Drawing Equipments

•

Set squares of 60o

and 45o

•

Compass•

Scale rulers (1:100, 1:200, 1:250, 1:300, 1:400 and 1:500) in metric units

•

Pencils •

Erasers

•

Erasing shield•

ACAD 2009

Set square

Scale ruler

compass

Scale rules

The two types of scale rules

(a) Triangular cross-section

(b) Flat cross-section

Actual distance = 5mThe scale used is 1: 200The scale used is 1: 200Drawing distance = Drawing distance = 5000/200=25mm5000/200=25mm

25mm

Erasing shield

The red line is to be removed.

The border

Informationpanel

Title block

Title Block

Title Block•

Typical title block contains essential information required for the identification and interpretation of drawings. The information usually include

–

Project title e.g. Biological Sciences Building–

Drawing number with provision for revision suffix e.g. S/L/11 (B)

–

Drawing title e.g. 9th

Floor Layout Plan–

Projection symbol e.g. third angle projection symbol–

Scale e.g. 1:100–

Date of drawing e.g. August 1997–

Name of Client e.g. The University of Hong Kong–

Office of origin e.g. Ove

Arup & Partners HK Ltd–

Office project number e.g. 22003–

Identity of persons involved in the design, draughting

and checking

Title Block for this course

PROJECTIONS

Font height = 5mm

Font height = 3mm

Font height Font height = 4mm= 4mm

Font height = 5mm

Title Block

Title Block

Examples of size and position of title and information panels

A1 size

Used in this course

Some common practices

Title Block•

A standard title block is to be placed at the bottom right hand corner of the drawing.

•

The minimum border width is 20mm except that 25mm minimum is required for the left hand border.

25mm minimum25mm minimum

1mm 1mm

20mm minimum20mm minimum

Scale•

Drawings should be drawn with an appropriate scale so that all necessary information related to each drawing can be easily presented. Recommended scales for civil and structural engineering drawings are 1:10, 1:25 (1:20), 1:50, 1:100 and 1:200–

(dimensions on drawing : actual dimensions on site)

Linework

•

Different line thicknesses and line types•

For good presentation, all lines should be black and firm. Each line should be of consistent good presentation and easy reading.

Do not mix pencil and ink line on one drawing. Recommended thickness of lines and their typical applications are shown in the sketch attached.

Linework

Thickness of line and line types

(cut section)

and outlines of structural members

Various line thickness

Various line types

Linework

Thickness of line and line types

or Adjacent Structures (for information)

1mm min. for gaps 2-4mm long for line segment

1mm min. for gaps2-3mm for shorter line segment5-15mm for longer line segment

Various line types

Linework

Typical application

Linework

Typical application

Lettering

•

Avoid ambiguity, reading difficulty

and wrong interpretation

by others

•

If you can write neat lettering, it is easier for your future supervisors or clients to have confidence in

your work and in you.

•

Lettering

looks simple but it requires a lot of time and patience

to practice and to do

it well.

Why do we need good lettering in engineering drawings?

Lettering•

All writing should be black

and of consistent density.

They should be easily read and unambiguous.•

Either vertical or sloping characters can be used but they must not be mixed on any one drawing.

•

The height of capital characters should be about 7mm for titles and 2.5mm for notes and dimensions. For lower case letters, the height should be about 0.6 of the corresponding capitals.

Lettering

Application Drawing sheet size

Minimum character height

Upper case and numerals (mm)

Lower case (mm)

Titles, drawing numerals, etc.

A0, A1, A2 and A3 7 4

A4 5 3

Dimensions and notes

A0 3.5 2

A1, A2, A3 and A4 2.5 1.5

Common Heights of letters and numeralsExtracted from: Standard Method of Detailing Structural Concrete, The Institution of Structural Engineers and The Concrete Society (1989)

Lettering

Example of letters

Lettering

Guide lines for Lower case Letters

The guide lines are drawn softly and they do not need to be erased.

Presenting 3-D Civil/ Building Structures in 2-D Spaces

••

Option 1: Isometric ViewOption 1: Isometric View••

Option 2: ProjectionOption 2: Projection

x y

z

Isometric View

120o between coordinates axes

AABB

CC

DD

EE GG

FF

Only visible lines are shown

Draw a cube with lengths of 4 units

Note: Dimensions parallel

to the coordinate axes can be measured directly from figure

1 unit in x dir.

12

34

43

21

1

2

3

4

dimensions not measurable from the figure

x y

z

Isometric View

If the corners of unit length are removed from the cube:

Isometric View

x y

zWe can use this method to draw any 3D objects.

However, what are the drawbacks of using isometric view in engineering drawing?

Hidden parts have not been shown. It is difficult to show the dimensions and time consuming to draw a 3D object.

Isometric view Orthographic projections

Projection (First angle)

Front View(view projected onto y-z plane)

View of Left Side

Plan View

Side view put on the Side view put on the opposite sideopposite side

View of left Side

x y

z

y-z plane: plane of projection

Orthographic projections

Projection (Third angle)Isometric view

x y

z

Front View

View of Right Side

Plan View

Side view put on the Side view put on the viewing sideviewing side

View of Left Side

Projection

In general, any three orthogonal views (projections) are sufficient to present all information of an object.

Engineering drawings should be prepared using Third Angle Projection. This projection is illustrated in Fig.4

(i)

the elevation or side view of the member.(ii)

The plan or top view above the elevation.(iii)The views at each end looking directly on the end and

adjacent to it.(iv)

The bottom or plan view on the bottom side is drawn as a

view looking up from the under side.

Fig 4. – Example of third angle projection.

Projection

(i)

(ii)

(iii) (iii)

(iv)

Transferring dimensions between top and side views

•Using dividers

•Using scales

•Using 45o

miter (inclined) line

Projection

Top view

Side view

Front view

8

2 4 3

Transferring Isometric View into Third Angle Projections:

•

Three views required

•

Measure dimensions of lines parallel to coordinate axes

Projection

xy

z

Measure the coordinates of corner points

(x1 ,y1 ,z1 )

Dimensions of red

lines parallel to coordinate axes

can be measured directly from the figure

Poor

Projection

Outside corners intersect Poor

Good

Hidden lines intersect without a gap

PoorInside corners intersect but do not cross

Poor

PLAN

VIEW OF RIGHT SIDE

Projection

FRONT VIEW

Viewing direction

Try to Sketch the 3D View

SECTION A-A

SECTION B-B

Projection

DimensioningExtension Lines:

• Thin continuous lines

• Preferably starting just near outline of object

• Extending a little beyond dimension line

100

70Dimension Lines:

• Thin continuous lines

• Placed outside the view if practicable

• may be interrupted to insert dimensions

CLCentre lines (Symbol

)

• Thin

chain dotted lines

• To represent axes of symmetrical parts and to denote centers

CL

Fig. 5 Dimension lines and extension lines

Dimensioning

456

123

234

234

35

Dia 250

222DonDon’’t t over over dimensiondimension

Note: All units are in millimetres

unless otherwise specified

123

456

Placement of dimension lines and extension lines:

Fig 6. Placing of dimension lines

Dimensioning

Shorter insideAvoid overlapping of D line

Extension line extended to edge

D line outsidedrawing object

Fig 7. Use of arrow heads and dots

Fig 8. Inclined dimension lines

Dimensioning

General rule: number to be placed above dimension lines.

End of dimension line defined by arrow head

Limited space: (1) arrow head outside dimension line(2) use dot or circle instead of arrow head

Dimension to be given where shapes are shown:

Fig 9.

Dimensioning

Each dimension is given in the contour view

Every dimension is given in the wrong view

Simple rules for civil/structural drawings:Plan –

horizontal dimensions (x and y coordinates)Elevation/Section –

vertical dimensions (z coordinate)

doesn’t look like a circle

Recess

Dimensions to be lined up and grouped together as much as possible:

Fig 10.

Dimensioning

An application of dimensioning:

Fig 11.

Dimensioning

Elevation view

Plan view

View from Right side

3D viewDimensions shown

at contour views

Shorter dimensions put inside

No over dimensioning

The termination of dimension lines can be indicated by:

(a)

open arrowheads;

(b) solid arrowheads;

(d) Dots or circles on the dimension line.

(c) short oblique strokes cutting the dimensions line;

Termination of Dimension Lines

Dimensions should normally be to the nearest millimetre.

w3w

Length equal the width of arrowhead

Assignment 1•

6 problems on third angle projection•

1 from each problem sheet•

last digit of problem no. = last digit of university no.•

dimensioning required (to be rounded up to nearest mm)•

dimensions to be measured from figures•

font height for dimensions = 2.5mm•

font height for titles = 5mm•

use suitable drawing scale (2:1

or 3:1)•

A1-size hand drawings to be submitted.

Problem Sheets 1 –

4

Isometric View Problems

Problem sheet 1

A

A

B

B

C

C

Example

For locating the vertex

x

y

zSet up coordinate axes

Measure the dimensions to the nearest mm (or up to 0.5mm) For the lines parallel to

the coordinate axes

x1

y1

z1(x1 ,y1 ,z1 )After finding out

the coordinates for all the nodes, draw the three different views in third angle projection.

Show the measured dimensions

(up to millimeters) on the scaled drawing

Problem Sheets 5 –

6

Missing View Problems

3rd ANGLE PROJECTIONS

Problem sheet 5

Missing view(may have more than one solution) ?

Example

DUE DATE: DUE DATE: 44

November 2011November 2011(during the lecture)(during the lecture)

Use upper cases in the drawingUse upper cases in the drawingWrite down PLAN, FRONT VIEW or VIEW OF RIGHT SIDE below the view

Show the measured dimensions on the drawing

The End

References•

Standard Method of Detailing Structural Concrete, The Institution of Structural Engineers and The Concrete Society (1989)

•

A Hayward and F Weare, Steel Detailer’s Manual, Blackwell Scientific Publications, Oxford (1992)

•

BS 308 Engineering Drawing Practice, Parts 1-3 (1993)•

BS 1192 Construction Drawing Practice, Parts 1-5 (1987)•

James H. Earle, Drafting Technology, 2nd

Edition, Addison-

Wisley, Wokingham England, 1986

•

Frederick E. Giesecke

et al. Principles of Engineering Graphics, 2nd

Edition, Maxwell Macmillan, New York, 1994.

References•

R N Roth and L A Van Haeringen, Australian engineering drawing handbook, Parts 1-2, Barton, A.C.T. : Institution of Engineers (1998)

•

Highways Department Standard Drawings, HKSAR (1998)•

CAD Standard for Works Projects, Environment, Transport & Works Bureau, HKSAR (2002)

•

PNAP 58 Submissions to the Buildings Department•

PNAP 127 Colouring

of Plans –

Building (Administration) Regulation 14(3)

•

PNAP 135 Imaging Standards for Plans