ACE Prelims CIVIL... · Foreword UPSC Engineering Services in Civil Engineering Volume - I...

Website : www. aceengineeringpublications.com

ESE - 19CIVIL Engineering

(Volume - I)(Building Materials, Solid Mechanics, Structural Analysis, Design of Steel Structures,

Design of Concrete and Masonry Structures, Construction Practice, Planning and Management)

Previous years Objective Questions with Solutions, Subject wise & Chapter wise(1991 - 2018)

ACEEngineering Publications

(A Sister Concern of ACE Engineering Academy, Hyderabad)

Hyderabad | Delhi | Bhopal | Pune | Bhubaneswar | Bengaluru | Lucknow | Patna | Chennai | Vijayawada | Visakhapatnam | Tirupati | Kukatpally | Kolkata

ACE is the leading institute for coaching in ESE, GATE & PSUsH O: Sree Sindhi Guru Sangat Sabha Association, # 4-1-1236/1/A, King Koti, Abids, Hyderabad-500001.

Ph: 040-23234418 / 19 / 20 / 21, 040 - 24750437

11 All India 1st Ranks in ESE43 All India 1st Ranks in GATE

(Prelims)

Copyright © ACE Engineering Publications 2018

All rights reserved.

Published at :

Authors : Subject experts of ACE Engineering Academy, Hyderabad

While every effort has been made to avoid any mistake or omission, the publishers do not owe any responsibility for any damage or loss to any person on account of error or omission in this publication. Mistakes if any may be brought to the notice of the publishers, for further corrections in forthcoming editions, to the following Email-id. Email : [email protected]

First Edition 2011Revised Edition 2018

Printed at :Karshak Art Printers,Hyderabad.

Price : ₹. 920/-ISBN : 978-1-946581-85-3

ACE Engineering Publications

Sree Sindhi Guru Sangat Sabha Association,# 4-1-1236/1/A, King Koti, Abids, Hyderabad – 500001, Telangana, India.Phones : 040- 23234419 / 20 / 21 www.aceenggacademy.comEmail: [email protected] [email protected]

No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, digital, recording or otherwise, without the prior permission of the publishers.

ForewordUPSC Engineering Services in Civil Engineering

Volume - I Objective Questions: From 1991– 2018

The Stage-I (Prelims) of ESE – 2018 consists of two objective papers. Paper-I is of General Studies &

Engineering Aptitude. Paper-II is of Civil Engineering of 300 Marks and 3 hours duration. In stage-II

(Mains), the technical syllabus is divided into two papers. The subjects included in this volume are:

1. Building Materials 2. Soil Mechanics

3. Structural Analysis 4. Design of Steel Structures

5. Design of Concrete and Masonry Structure 6. Construction Practice, Planning & Management

Keeping in view of the above topics, the present Volume-I for prelims of new pattern is redesigned using the previous

questions from 1992 onwards.

The style, quality and content of the Solutions for previous ESE Questions of Civil Engineering, will encourage the reader,

especially the student whether above average, average or below average to learn the concept and answer the question in the

subject without any tension. However it is the reader who should confirm this and any comments and suggestions would be

pleasantly received by the Academy.

It is observed that majority of ESE objective Questions are being asked as it is in many PSUs, state service commission,

state electricity boards and even in GATE exam. Hence we strongly recommend all students who are competing for various

competitive exams to use this book according to the syllabus of the exam concerned. This book can also be used by fresh

Teachers in engineering colleges to improve their Concepts.

We proudly say that questions and solutions right from 1992 onwards are given in this book. The questions which appeared

early 90’s are most conceptual oriented and these are being repeated in the recent exams in a different way. Hence we advise

the students to practice these questions compulsorily. The student is also advised to analyze why only a particular option is

correct and why not others. Evaluate yourself, in which case, these other options are correct. With this approach you yourself

can develop four questions out of one question.

The student is advised to solve the problems without referring to the solutions. The student has to analyze the given question

carefully, identify the concept on which the question is framed, recall the relevant equations, find out the desired answer,

verify the answer with the final key such as (a), (b), (c), (d), then go through the hints to clarify his/her answer. The student

is advised to have a standard text book ready for reference to strengthen the related concepts, if necessary. The student is

advised not to write the solution steps in the space around the question. By doing so, he loses an opportunity of effective

revision.

With best wishes to all those who wish to go through the following pages.

Y.V. Gopala Krishna Murthy,M Tech. MIE,

Chairman & Managing Director,ACE Engineering Academy,

ACE Engineering Publications.

Weightage of Subjects in Engineering Services Examination

Civil Engineering (2012 – 2018)

Volume - I (OBJECTIVE)

SUBJECTNo. of Questions

2012 2013 2014 2015 2016 2017

Building Materials 26 20 29 23 25 12

Solid Mechanics 32 22 31 43 28 21

Structural Analysis 15 19 17 11 12 14

Design of Steel structures 15 13 17 15 07 06

Design of Concrete & Masonry Structures 22 11 11 16 18 09

Construction Practice, Planning & Management 10 35 15 12 30 04

Total 120 120 120 120 120 66

ESE – 2018 (Prelims, Subjectwise Weightage)

SUBJECT No. of Questions SUBJECT No. of

Questions

Building Materials 13 Hydrology 07

Solid Mechanics 16 Irrigation Engineering 03

Structural Analysis 12 Environmental Engineering 16

Design of Steel structures 08 Geotechnical Engineering 17

Design of Concrete & Masonry Structures 08 Surveying 05

Construction Practice, Planning and Management 02 Geology 0

Fluid Mechanics & Hydraulic Machines 32

Transportation Engineering (Highways, Railways, Airports, Docks & Harbours,Tunnels)

11

TOTAL 150

Previous years Questions with Solutions, Subject wise & Chapter wise Civil Engineering (1991 – 2018)

MAIN INDEX

S.No. Name of the Subject Page No.

1 Building Materials 01 – 136

2 Solid Mechanics 137 – 412

3 Structural Analysis 413 – 622

4 Design of Steel Structures 623 – 724

5 Design of Concrete and Masonry Structures 725 – 874

6 Construction Practice, Planning and Management 875 - 1009

PageNo.1

UPSC Engineering Service (ESE)

SYLLABUS

Building Materials:

Stone, Lime, Glass, Plastics, Steel, FRP, Ceramics, Aluminum, Fly Ash, Basic Admixtures, Timber,

Bricks and Aggregates: Classification, properties and selection criteria; Cement: Types, Composition,

Properties, Uses, Specifications andvarious Tests; Lime & Cement Mortars and Concrete: Properties

andvarious Tests; Design of Concrete Mixes: Proportioning of aggregate sand methods of mix design.

PageNo.2

PreviousESEQuestions&Solutions

To BuildingMaterials

PageNo.3

ChapterNo.

NameoftheChapter QuestionsPageNo.

SolutionsPageNo.

01 Timber 04–17 18–31

02 Bricks 32–42 43–51

03 Cement 52–66 67–75

04 Aggregates 76–82 83–86

05 CementMortars 87–92 93–95

06 ConcreteandReinforcement 96–116 117–128

07 BrickMasonry 129–131 132–133

08 MiscellaneousTopics 134–134 135–136

CONTENTS

ACE Engineering Publications Hyderabad|Delhi|Bhopal|Pune|Bhubaneswar| Lucknow|Patna|Bengaluru|Chennai|Vijayawada|Vizag |Tirupati | Kukatpally| Kolkata

01. According to the relevant IS code, the weight

of the timber is to be reckoned at a moisture

content of (ESE – 1995)

(a) Zero (b) 4% (c) 8% (d) 12%

02. The strength of timber is maximum when

load applied is (ESE – 1995)

(a) Parallel to grain

(b) Perpendicular to grain

(c) Inclined at 45o to grain

(d) Inclined at 60o to grain

03. Assertion (A): Dimensional changes in

wood result due to variation in the moisture

content of the wood with atmospheric

condition.

Reason (R): The cell walls in wood are

highly hygroscopic and when exposed to

moisture, absorb large amounts of water and

swell. (ESE – 1995)

Codes:

(a) Both A and R are true and R is the

correct explanation of A

(b) Both A and R are true but R is not a

correct explanation of A

(c) A is true but R is false

(d) A is false but R is true

04. The nail diameter should not be more than

(t = least thickness of the wooden member to

be connected. (ESE-1996)

(a) t/6 (b) t/ 8 (c) t/ 10 (d) t/12

05. The expansion and shrinkage of ply woods

are comparatively very low as (ESE-1996)

(a) They are held in position by adhesives

(b) They are glued under pressure

(c) Plies are placed at right angles to each

other

(d) They are prepared from veneers

06. Seasoning of timber is required to

(ESE-1996)

(a) Soften the timber

(b) Harden the timber

(c) Straighten the timber

(d) Remove sap from the timber

07. Assertion (A): While painting on flush doors

of plywood, putty-filling is done after prime

coat.

Reason (R): This reduces the quantity of

paint and effort involved in the regular coats

of the paints. (ESE-1996)

Timber 1Chapter

: 5 : Timber


08. Match List-I with List-II and select the correct

answer using the codes given below the lists.

(ESE-1997)

List-I List-II

A. Deciduous 1. Soft wood

B. Conifer 2. Hard wood

C. Endogenous 3. Eucalyptus

D. Exogenous 4. Bamboo

Codes:

A B C D A B C D

(a) 1 2 3 4 (b) 2 1 3 4

(c) 2 1 4 3 (d) 1 2 4 3

09. During the conversion of timber by sawing, in

order to obtain strong timber pieces, the cuts

should be made by (ESE-1997)

(a) Ordinary sawing (b) Tangential sawing

(c) Quarter sawing (d) Radial sawing

10. A timber beam of effective span L and of

cross-section b d is said to be laterally

supported if d/b and L/b are respectively

(ESE-1997)

(a) Less than 1 and less than 48

(b) Less than 2 and less than 49

(c) Less than 3 and less than 50

(d) Less than 4 and less than 51

11. A timber column is made up of two individual

members with longitudinal axes parallel,

separated at the ends and middle points of

their length by blocking, and joined at the

ends by timber connectors. Such a column is

called (ESE-1997)

(a) Built-up column (b) Composite column

(c) Spaced column (d) Flitched column

12. The modulus of elasticity of timber is about

(ESE-1997)

(a) 24 mm/N100.1to5.0

(b) 24 mm/N105.1to0.1

(c) 24 mm/N100.2to5.1

(d) 24 mm/N105.2to0.2

13. The moisture content in structural timber

should be (ESE-1998)

(a) Less than 5% (b) 5 to10%

(c) 10 to 20% (d) 15 to 25%

14. Match List-I with List-II and select the correct

answer using the codes given below the lists:

(ESE-1998)

List-I

A. The innermost part of core of the stem of

a tree

B. The vascular tissue which encloses the

pith

C. A cellular tissue and woody fibre

arranged in distinct concentric circles

D. The thin layer below the bark not

converted into sapwood as yet

List-II

1. Transverse septa (medullary rays)

2. Annual rings

3. The cambium layer

: 6 : Building Materials


4. The outermost cover or skin of the stem

5. Medulla (pith)

Codes:

A B C D A B C D

(a) 2 5 3 4 (b) 5 1 2 3

(c) 4 3 2 1 (d) 5 1 4 3

15. Consider the following statements:

Casein glue is

1. obtained from milk

2. obtained form the blood of animals

3. used in painting of metals

4. used in the plywood industry

5. white in colour

6. red in colour

Which of these statements are correct?

(ESE-1998)

(a) 1, 3 and 5 (b) 1, 4 and 5

(c) 2, 3 and 6 (d) 2, 4 and 6

16. Match List-I (Component of scaffolding)

with List-II (Function) and select the correct

answer using the codes given below the lists:

(ESE-1998)

List-I List-II

A. Putlog 1. Diagonal member

B. Ledger 2. Vertical member

C. Brace 3. Horizontal member

D. Standard 4. Transverse member

Codes:

A B C D A B C D

(a) 4 3 1 2 (b) 4 3 2 1

(c) 3 4 1 2 (d) 3 4 2 1

17. Assertion (A): Within a given species, green

timber of large moisture content dries in the

same length of time as that of lower moisture

content.

Reason(R): The sapwood which contains

most of the moisture, dries more

rapidly than the heartwood.

(ESE-1999)

18. Consider the following methods of

preservation of timber:

1. Dipping

2. Brushing or spraying

3. Pressure impregnation

The correct sequence in decreasing order of

the effectiveness of these methods of

preservation is (ESE-1999)

(a) 1, 2, 3 (b) 2, 1, 3

(c) 3, 1, 2 (d) 3, 2, 1

19. Radial splits in timber originating from

‘bark’ and narrowing towards the ‘pith’ are

known as (ESE-1999)

(a) Heart shakes (b) Star shakes

(c) Cup shakes (d) Knots

20. The moisture content in a properly seasoned

timber will be in the range of

(ESE-2000)

(a) 5% to 8% (b) 8% to 10%

(c) 10% to 12% (d) 12% to 15%

: 7 : Timber


21. The strength of timber is maximum in the

direction (ESE-2000)

(a) Perpendicular to the grains

(b) Parallel to the grains

(c) 45o to the grains

(d) At all angles

22. On application of external stress on timbers, it

behaves like (ESE – 2001)

(a) An elastic material

(b) Non-elastic material

(c) Visco elastic material

(d) Non-visco elastic material

23. The ratio of tangential shrinkage to radial

shrinkage of wood due to reduction in

moisture content is (ESE– 2001)

(a) In the range from 3.1 to 5.1

(b) In the range from 2 to 3

(c) In the range from 1 to 2

(d) Less than or equal to 1

24. The compressive strength in structural timber

is minimum in a direction (ESE – 2001)

(a) Parallel to the grains

(b) Perpendicular to the grains

(c) Along an axis inclined at 45o to the grains

(d) Along an axis inclined at 60o to the grains

25. Assertion (A): Trees which have broad

leaves and shed in the autumn are classified

as hard woods, while trees having needle-like

leaves, broadly evergreen are classified as

soft woods.

Reason (R): The term hard wood and soft

wood in relation to a species of tree do not

necessarily indicate relative hardness or

density. (ESE-2002)

26. Assertion (A): Knots, one of the common

features in wood, are associated with the

beginning of branches.

Reason (R): Knots greatly improve the

workability. (ESE-2002)

27. Timber can be made reasonably fire-resistant

by (ESE-2002)

(a) Soaking it in ammonium sulphate

(b) Coating with tar paint

(c) Pumping creosote oil into timber under

high pressure

(d) Seasoning process

28. Which one of the following statements is the

correct description of the structure of fibre

board? (ESE-2002)

(a) Thin slices of superior quality of wood

are Glued and pressed on the surface of

Inferior wood.

(b) Steamed mass of wood dusts, wood wool

and other vegetable fibres are pressed

hard a thickness varying from 3 mm to

12 mm.

(c) Thin and narrow wood shavings are

soaked in a refractory binder material

and pressed Hard.

(d) Wood veneer backed by fabric mat.



29. Consider the following methods of

preservation of timber:

1. Pressure application

2. Brush application

3. Dipping

4. Open tank application

The correct sequence of this method in the

increasing order of their effectiveness is

(ESE-2002)

(a) 1, 3, 4, 2 (b) 3, 4, 2, 1

(c) 2, 3, 4, 1 (d) 4, 2, 1, 3

30. Match List-I (Name of defect) with List-II

(Definition) and select the correct answer

using the codes given below the lists:

(ESE-2002)

List-I

A. Cupping

B. Bowing

C. Chucks

D. Knots

List-II

1. Caused by wood limbs encased by the

wood of the free trunk

2. Caused by grain irregularities in the board

and can be eliminated by proper stacking

3. Small cracks appearing at the ends of

boards caused by too rapid drying

4. Unequal shrinking in the radial and

tangential direction

Codes:

A B C D A B C D

(a) 1 2 3 4 (b) 4 3 2 1

(c) 1 3 2 4 (d) 4 2 3 1

31. The maximum deflection in timber beams or

joints should not be greater than (ESE-2002)

(a) span/300 (b) span/325

(c) span/360 (d) span/380

32. Assertion(A): Timbers used for engineering

construction are derived from deciduous

Trees.

Reason (R): Deciduous trees yield hard

wood while conifers yield soft wood.

(ESE-2003)

33. Assertion(A): Dry rot is a disease in wood

caused by spores germinating in wood Cells.

Reason(R): Decomposition and putrefaction

of tissues of a standing tree are indicators of

dry rot. (ESE-2003)

34. A well-seasoned timber has a moisture

content of about (ESE-2003)

(a) 15% to 20% (b) 10% to 12%

(c) 5% to 8% (d) 2% to 3%

35. Dry rot in timber is caused by (ESE-2003)

(a) lack of ventilation

(b) lack of light

(c) immersion in water

(d) alternate wet and dry atmosphere

: 9 : Timber


36. Wood is impregnated with creosote oil in

order to (ESE-2003)

(a) change its colour

(b) protect against fungi

(c) protect the annular layers

(d) fill up the pores


Hardest timber is obtained from the wood

grown in

1. the moderately dry climatic regions

2. the Himalayan slopes

3. the open areas

4. the thin jungles


(ESE-2004)

(a) 1 and 3 (b) 1 and 4

(c) 2 and 3 (d) 2 and 4


Dry rot in timber is due to

1. stacking wood in open areas

2. lack of ventilation

3. decomposition of sap

4. lack of preservatives


(ESE-2004) (a) 1 and 2 (b) 1 and 3

(c) 2 and 3 (d) 3 and 4

39. In static bending test Match List-I (Type of

failure) with List-II (Figure) and select the

correct answer using the codes given below

the lists: (ESE-2004)

List-I

A. Simple tension

B. Crossing grain tension

C. Splintering tension

D. Brash tension

List-II

1.

2.

3.

4.

Codes:

A B C D A B C D

(a) 1 4 3 2 (b) 4 1 3 2

(c) 4 1 2 3 (d) 1 4 2 3

40. Match List-I (Product) with List-II (it use)

and select the correct answer using the

codes given below the lists: (ESE-2004)

List- I

A. Fibre board

B. Heartwood

C. Laminated timber

D. Plywood

List-II

1. Panelling

2. Insulation

3. Scantling

4. Arches/Trusses



Codes:

A B C D A B C D

(a) 3 2 1 4 (b) 3 2 4 1

(c) 2 3 4 1 (d) 2 3 1 4

41. Match List-I (Term) with List-II (Brief

description) and select the correct answer


(ESE-2005) List-I A. Heart shakes

B. Knot

C. Rot

D. Sap wood

List-II

1. Disintegration caused by fungi

2. Outer layers of a log of wood

3. A branch base embedded in timber by

natural growth

4. Cracks widest at centre and diminishing

towards the outer circumference

Codes:

A B C D A B C D

(a) 1 3 4 2 (b) 4 2 1 3

(c) 1 2 4 3 (d) 4 3 1 2


The disease of dry rot in timber is caused by

1. complete submergence in water

2. alternate wet and dry condition

3. lack of ventilation

Which of these statements is/are correct?

(ESE-2005)

(a) 1 only (b) 3 only

(c) 2 only (d) 2 and 3

43. Which one of the following is the correct

statement? (ESE-2005)

The strength of timber

(a) is maximum in a direction parallel to the

grain

(b) is maximum in a direction perpendicular

to the grain

(c) is maximum in direction 45o to the

grain

(d) remain same in all directions


Kiln seasoning of timber results in

1. reduced density

2. reduced life

3. dimensional stability


(ESE-2005)

(a) 1, 2 and 3 (b) 1 only

(c) 2 and 3 (d) 1 and 3

45. In a tree, the cambium layer is situated

between (ESE-2005)

(a) the outer bark and inner bark

(b) the inner bark and sap wood

(c) the sap wood and heart wood

(d) the pith and heart wood

: 11 : Timber


46. The timber preservative “creosote” belongs to

the group of (ESE-2006)

(a) water soluble salts

(b) organic solvent type

(c) tar oil type

(d) inorganic solvent type

47. The strength of timber is maximum in a

direction (ESE-2006)

(a) parallel to the grains

(b) perpendicular to the grains

(c) 45o to the grains

(d) 30o to the grains

48. Match List-I (Species) with List-II (Uses)

and select the correct answer using the codes

given below the list: (ESE-2006)

List-I List-II

A. Babul 1. Tennis rackets

B. Ben teak 2. Boats

C. Bijasal 3. Agricultural tools

D. Mulberry 4. Furniture

Codes:

A B C D A B C D

(a) 4 1 3 2 (b) 3 2 4 1

(c) 4 2 3 1 (d) 3 1 4 2

49. Which one of the following is the most

preferred wood for high quality and durable

furniture? (ESE-2007)

(a) Sandalwood (b) Deodar wood

(c) Teakwood (d) Shisham wood

50. As a natural material, timber is which one of

the following? (ESE-2007)

(a) Isotropic (b) Anisotropic

(c) Homogeneous (d) Heterogeneous

51. Shear strength of timber depends on which

one of the following? (ESE-2007)

(a) Lignin with fibres (b) Medullary rays

(c) Heartwood (d) Sapwood

52. The defect which develops due to

uncontrolled and non-uniform loss of

moisture from wood is known as which one

of the following?

(ESE-2007)

(a) Knot (b) Shake

(c) Warping (d) Cross gain

53. Assertion (A): Wooden window shutters

should be fitted, leaving proper tolerances for

dimensional changes.

Reason (R): Timber sections change in

volume with change in seasons.

(ESE-2007)

54. Match List-I (Wood element) with List –II

(Description) and select the correct answer


(ESE-2008) List –I

A. Pith B. Sapwood

C. Heart wood D. Cambium layer



List-II

1. Innermost portion of the tree

2. Inner annual rings surrounding the pith

3. Outermost annual rings

4. Thin layer of sap between sapwood and

inner Bark

Codes:

A B C D A B C D

(a) 1 3 2 4 (b) 2 4 2 3

(c) 1 4 2 3 (d) 2 3 1 4

55. In respect of moisture content in wood, the

fiber saturation point refers to which one of

The following? (ESE-2008)

(a) Free water present in the cells

(b) Free water present in cell walls and cell

(c) No moisture present in cell walls and cell

cavities

(d) No free water exists in cell cavities but

cell walls are saturated

56. The moisture content of timber used in

building frames can be (ESE-2008)

(a) 2% to 5% (b) 8% to 12%

(c) 12% to 18% (d) >20%

57. Match List – I (Disease of timber) with

List – II (Effect of disease) and select the

correct answer using the codes given below


List-I

A. Dry rot B. Grey rot

C. Wet rot D. White rot

List-II

1. Attack of sapwood by fungus

2. Damage to wood fibers due to chemical

decomposition of wood

3. Destruction of cellulose of wood due to

fungal attack

4. Destruction of lignin of wood due to

fungal attack

Codes:

A B C D A B C D

(a) 1 3 2 4 (b) 1 4 2 3

(c) 2 3 1 4 (d) 2 4 1 3

58. What is the ratio of the elastic modulus of

structural timber in longitudinal direction to

that in the transverse direction?

(ESE-2009)

(a) 1/2 to 1 (b) 1/10 to 1/20

(c) 1 to 2 (d) 10 to 20

59. What is the modulus of elasticity of standard

timber (Group B) in (MN/cm2)?

(ESE-2009)

(a) 0.5 to 1.0 (b) 1.0 to 1.25

(c) 1.25 to 1.5 (d) 1.5 to 1.75

60. What is the treatment for making timber fire

resistant? (ESE-2009)

(a) ASCU treatment (b) Abel’s process

(c) Creosoting (d) Tarring

: 13 : Timber


61. How is the process of treatment of wood

using a preservative solution and forcing in

at a pressure designated? (ESE-2009)

(a) Rueping process (b) Lawry process

(c) Full cell process (d) Empty cell process


1. Cambium layer is between sapwood and

heartwood.

2. Heartwood is otherwise termed as

deadwood.

3. Timber used for construction is obtained

form heartwood.


(ESE-2010)

(a) 1, 2 and 3 (b) 2 and 3 only

(c) 1 and 2 only (d) 2 only

63. The advantages in using plywood is that the

(ESE-2010)

(a) tensile strength is equal in all directions

(b) higher tensile strength in longer direction

(c) higher tensile strength in shorter direction

(d) lower tensile strength in longer direction

64. Which one of the following statements is

correct as regards tensile strength of wood?

(ESE-2010)

(a) Minimum in the direction parallel to the

grains

(b) Maximum in the direction parallel to the

grains

(c) Maximum in the direction across the

grains

(d) Same in all directions

65. Consider the following characteristics

regarding timber: (ESE-2010)

1. Stronger variety

2. Ability to take very smooth finish

3. Toughness

4. Difficult to season

Which of the above characteristics is/are

essential for timber to be used as beams?

(a) 1 only (b) 2 and 3

(c) 3 and 4 (d) 1 and 3


1. Dry rot in sap wood is caused by fungal

attack.

2. Brown rot in coniferous wood is a result

of fungal attack.

3. Alternate wetting and drying of

unseasoned timber causes ‘powdery’

form of decay in wood.


(ESE-2011)

(a) 1, 2 and 3 (b) 1 and 2 only

(c) 2 and 3 only (d) 1 and 3 only


Fibre saturation point in wood is reached

when

1. Free water is removed.

2. Cell water is removed



3. Shrinkage of wood is rapid

4. Strength gain is rapid


(ESE-2011)

(a) 1, 2 and 3 (b) 1 and 2 only

(c) 2 and 4 only (d) 1, 3 and 4

68. The radial splits which are wider on the

outside of the log and narrower towards the

pith are known as (ESE-2012)

(a) star shakes (b) annular rings

(c) cup shakes (d) heart shakes

69. Consider the following distinguishing

characteristics of hardwood:

1. They have distinct annular rings

2. They are non resinous

Which of these characteristics of hardwood

is/are correct? (ESE-2012)

(a)1 only (b) 2 only

(c) Both 1 and 2 (d) Neither 1 nor 2

70. Consider the following statements on the

specific gravity of wood:

1. It is always greater than 2.

2. It is less than 1.

3. It is not dependent upon temperature and

equilibrium moisture content.

4. It is dependent upon type of species.


(ESE-2012)

(a) 1, 2, 3 and 4 only (b) 1 and 3 only


71. The age of a log of timber can be estimated

by (ESE-2012)

(a) diameter of pith

(b) thickness of bark

(c) number of annular rings

(d) number of medullary rays


Seasoning of timber results in

1. increased strength

2. increased durability

3. reduced resilience

4. increased dimensional stability


(ESE-2012)

(a) 1, 2 and 4 (b) 1, 2 and 3

(c) 1, 3 and 4 (d) 2, 3 and 4

73. Match List – I with List – II and select the

correct answer using the code given below


List – I

A. Plywood

B. Fiberboard

C. Laminated timber

D. Commercial block-board

List – II

1. Furniture

2. Cantilever arches

3. Insulation

4. Lining of form-work in concrete

: 15 : Timber


Codes:

A B C D

(a) 1 2 3 4

(b) 4 3 2 1

(c) 1 3 2 4

(d) 4 2 3 1

74. Statement – I: Planks sawn from trees with

twisted fibers are stronger than those cut

from trees with normal growth.

Statement – II Timber from trees with

twisted fibers is used as poles.

(ESE-2012)

75. Statement-I: Timber suitable for tension

members is obtained from coniferous trees.

Statement-II: Coniferous trees have distinct

annular rings and straight grains.

(ESE-2012)

76. Which of the following statements are

correct?

1. Knots in a tree affect the continuity of

fibres.

2. Nail knots do not influence the strength

of timber.

3. Druxiness of wood is not a defect

4. Tall trees with twisted fibres given good

timber for poles (ESE – 2013)

(a) 1, 2 and 3 and 4 (b) 1, 2 and 4 only

(c) 1, 2 and 3 only (d) 2, 3 and 4 only

77. Excrescences in wood are:

1. Defects found in trees

2. Formed due to injuries inflicted on trees

when they are growing

3. Defects which render wood suitable as

firewood only

(ESE – 2013)

(a) 1, 2 and 3 (b) 1 and 2 only


78. What treatment is adopted for making timber

fire-resistant? (ESE – 2013)

(a) ASCU treatment (b) Abel’s process

(c) Creosoting (d) Tarring

79. Deterioration of structure of timber due to

dry rot is:

1. Caused by fungi

2. Due to dry-spell after heavy rains

3. Due to attack of termites

4. Indicated by surface stripes on

scantlings (ESE – 2013)

(a) 1 and 2 (b) 3 and 4

(c) 2 and 3 (d) 1 and 4

80. Alternate wetting and drying of timber:

1. Results in shrinkage and swelling

2. Brings about wet rot onset

3. Increases the durability

4. Causes transmission of spores from

germination (ESE – 2013)

(a) 1, 2 3 and 4 (b) 1, 2 and 4 only

(c) 1, 2 and 3 only (d) 2, 3 and 4 only



81. Which IS code is used for classification of

timber for seasoning purposes?

(ESE – 2014)

(a) IS: 4970-1973 (b) IS: 1708-1969

(c) IS: 1141-1958 (d) IS: 399-1963

82. Consider the following with regard to ‘the

application of preservation of timber ’:

1. increase in the life span of the member

2. increase in the strength of the timber

3. removal of moisture

4. prevention of growth of fungi by killing

them

Which of the above are correct?(ESE – 2014)

(a) 1,2,3 and 4 (b) 2 and 4 only


83. The plies in plywood are so placed that the

grains of each ply are (ESE – 2014)

(a) parallel to each other

(b) at right angle to one another

(c) 45 oblique to adjacent grain

(d) not constrained by any consideration

84. AsCu, a preservative for wood, developed by

the Forest Research Institute, Dehradun,

comprises of chemicals:

As2O5 . 2H2O, CuSO4. 5H2O and K2 Cr2O7 in

the proportion of

(ESE – 2015)

(a) 1 : 1 : 1 (b) 1 : 2 : 3

(c) 1 : 2 : 4 (d) 1 : 3 : 4

85. The minimum number of annular rings to be

seen in every 2.54 cm in the radial direction

from the core for timber to be classified as

‘Dense’ is (ESE – 2015)

(a) 10 (b) 20 (c) 25 (d) 30

86. Statement (I): Timber suitable for furniture

is obtained from conifers only.

Statement (II): Woods with distinct annual

rings are conifers. (ESE – 2015)

87. Statement (I): Seasoning of timber gives

dimensional stability, safety against attack by

fungi and improved workability.

Statement (II): Seasoning of timber removes

moisture in the form of sap from timber.

(ESE – 2015)


1. There will be no defects in select grade

timbers.

2. The codal values for strength of grade-II

timber without defects may be reduced

by 37.5%

3. For timber used as columns, the

permissible stress in ungraded timbers is

adopted with a multiplying factor of

0.50.

4. In case of wind force and earthquakes a

modification factor of 1.33 is adopted.

Which of the above statements are correct?

(ESE – 2016) (a) 1 and 3 only (b) 1 and 4 only


: 17 : Timber


89. Consider the following statements regarding

timber:

1. The strength of timber increases by Kiln

seasoning.

2. Cutting of wood is to be done prior to

treatment.

3. Water seasoning is good for prevention

of warping.

4. ASCU treatment enhances the strength

of wood.

Which of the above statements are correct?

(ESE – 2016)

(a) 1, 2 and 3 only (b) 2, 3 and 4 only

(c) 1, 3 and 4 only (d) 1, 2, 3 and 4

90. Gas(es) emitted during rotting or

decomposition of timber is/are mainly

(ESE – 2016)

(a) Methane and Hydrogen

(b) Hydrogen Sulphide

(c) Carbonic acid and Hydrogen

(d) Ammonia

91. In the cross-section of a timber, cambium

layer can occur in (ESE – 2016)

(a) Inner Bark and Sap Wood

(b) Pith and Heart Wood

(c) Sap Wood and Heart Wood

(d) Outer Bark and Sap Wood

92. Statement (I): Splitting of fibres is a type of

seasoning defect in wood

Statement (II): Seasoning of timber is a

general requirement for structural purposes.

(ESE – 2016)

93. Statement (I): Hardwoods are used in

special purpose heavy constructions.

Statement (II): Hardwoods too are porous in

nature. (ESE – 2016)

94. Statement (I): ‘Compreg’ timbers have

higher specific gravity of up to 1.30 and are

stronger than other timbers.

Statement (II): Impregnation of resins and

special curing methods are adopted to

develop ‘Compreg’ timbers (ESE – 2017)

95. Statement (I): Air seasoning of structural

timber renders it more durable, tough and

elastic.

Statement (II): Air seasoning of timber is

the most economical and eco-friendly

method of treatment when time is not a

constraining criterion. (ESE – 2018)

`



Key Sheet

01. (d) 02. (a) 03. (a) 04. (a) 05. (c) 06. (d) 07. (a) 08. (c) 09. (d) 10. (c)

11. (c) 12. (a) 13. (c) 14. (b) 15. (b) 16. (a) 17. (d) 18. (c) 19. (b) 20. (c)

21. (b) 22. (a) 23. (a) 24. (b) 25. (b) 26. (d) 27. (a) 28. (b) 29. (c) 30. (d)

31. (a) 32. (a) 33. (a) 34. (b) 35. (d) 36. (b) 37. (a) 38. (c) 39. (a) 40. (c)

41. (d) 42. (c) 43. (a) 44. (d) 45. (b) 46. (c) 47. (a) 48. (b) 49. (c) 50. (c)

51. (a) 52. (c) 53. (a) 54. (a) 55. (d) 56. (b) 57. (a) 58. (c) 59. (b) 60. (b)

61. (b) 62. (b) 63. (a) 64. (b) 65. (d) 66. (a) 67. (d) 68. (a) 69. (b) 70. (d)

71. (c) 72. (d) 73. (b) 74. (d) 75. (a) 76. (b) 77. (b) 78. (b) 79. (a) 80. (b)

81. (c) 82. (c) 83. (b) 84. (d) 85. (a) 86. (d) 87. (a) 88. (b) 89. (a) 90. (c)

91. (a) 92. (b) 93. (b) 94. (a) 95. (a)

01. Ans: (d)

Sol: According to IS:399 weight of timber is

taken at standard moisture content ≯ 12%.

02. Ans: (a)

Sol: For good tensile strength, load should be

applied parallel to grains.

For good compressive strength, load should

be applied perpendicular to grains.

Tensile strength perpendicular to grains

is 10-20 times more than its strength

perpendicular to grains.

Tensile strength depends on density of

wood.

Compressive strength of wood is half of

the corresponding tensile strength.

Shearing strength of wood is 10 to 15%

of its tensile strength.

Solutions

: 19 : Timber


In the question maximum strength of

timber is asked. It must be tensile

strength of timber.

Therefore, tensile strength is maximum

parallel to grains.

03. Ans: (a)

Sol: Moisture gets deposited on cell walls of

wood due to atmospheric changes.

Therefore volumetric changes occur in

wood.

Cell walls of wood are highly hygroscopic

(they absorb moisture from air) in humid

climatic conditions.

Due to increase in moisture level volumetric

and dimensional changes occur.

(The student should think logically to pick

up right answer)

04. Ans: (a)

Sol: The diameter of nail should be within a

range of 4

1 to

6

1 of thickness of wooden

block.

05. Ans: (c)

Sol. Ply arrangement should be right angular to

each other in alternate layers to have less

shrinkage and expansions.

06. Ans: (d)

Sol: Seasoning is the process of removing

sapwood and moisture in timber. Seasoning

will not soften or harden the timber. It will

not increase the strength.

Due to seasoning strength, elasticity and durability properties are developed.

07. Ans: (a)

Sol: After prime coat, the minute voids on

timber surface are filled up, then putty is

applied, so that the total quality of paint

used can be reduced.

08. Ans: (c)

Sol: Endogeneous- Bamboo (C-4)

Deciduous – hardwood (A-2)

Endogenous trees: These trees grow along

length Bamboo, Canes, Palms, Coconuts,

limited engineering use.

Exogenous trees:

Grow outwards Conifers (narrow leaves) like pine and

fir and all deciduous (broad leaves) teak & rose wood.

These are engineering timbers. Deciduous: The trees which shed leaves in

autumn are deciduous.

These are widely used in engineering

construction

Eg: Oak, Maple, Lemon

These give hard wood

Conifers:

Tree with narrow leaves Gives soft wood.



09. Ans: (d)

Sol: Radial sawing gives strong timber so that

the layer distribution is uniform.

Quarter sawing:

Also called quarter cutting

Growth rings are parallel to the short

face.

Long face of every board is close to

radial face.

Best for hard wood which collapse

during drying.

Advantages:

Best grains show on face

Good wearing surface for floors,

furniture.

Low width shrinkage on drying

Less wrap and cupping

Can be easily reconditioned

Disadvantages:

Slower seasoning

Nailing on face more prone to splitting

Tangential Cutting / Back Sawn Cutting

Helps to obtain high grade timber from

legs

In this short face is close to a radial face

and long face is close to a tangential

face.

For asesthetic appearance this method is

used.

The maximum depth can be just less

than the diameter of the log

Advantages:

Gives strongest boards used for beams &

boards

Seasons more rapidly

Good figure on face

Less prone to splitting when nailing

Wide sections are possible

Few knots on edge

Disadvantages:

Shrink more across when drying

More likely to warp and cup.

Collapsed timber is more difficult to re-

condition.

Radial Sawn Timber:

It makes optimal usage of logs

Because of cutting pattern, each piece of

radially sawn timber is a wedge shape. It

has sap wood on the wider edge and pith

or core wood at the point.

Used for flooring, clading, decking,

poles, wedges and timber screens.

Advantages:

Dimensional stability

Less prone to warping, cupping

Less waste in milling

: 21 : Timber


Disadvantages:

Wedge shape cross-section

More difficult to detail

More difficult to stack

Through sawing/ ordinary sawing:

This is most common method of sawing

The log is cut in parallel cuts in the

direction of the grains.

Advantages:

Low cost and fast

Maximum width of logs obtained from

log

Little wastage

Reveals attractive grain pattern, especially

in softwoods.

Disadvantages:

Not suitable for structural timber

With this method cupping caused by

tangential shrinkage is a problem (cupping

is the warping of the plank away from the

heart of the face)

12. Ans: (a)

Sol: Modulus of Elasticity of timber

Group A > 12.5 kN/mm2

Group B 9.8 – 12.5 kN/mm2

Group C 5.6 – 9.8 kN/mm2

13. Ans: (c)

Sol: Moisture content of good timber will be

around 10-20% according to atmospheric

humidity of a place.

Most appropriate answer is (c)

14. Ans: (b)

Sol: Innermost core of the stem of a tree is

pith (A should match to 5)

Concentric circles in a stem are annular

rings (C should match to 2)

15. Ans: (b)

Sol: Casein is the name for a family commonly

found in milk. This is white in colour.

Casein is also used in plywood industry as a

binder.

Through sawing Radial sawing

Tangential sawing Quarter sawing



FRAME

LEDGE

BRACES

BATTENS

16. Ans: (a)

Sol: In a door ledger is a horizontal member

(B-3)

Brace is a diagonal member (C-1)

Standard / Batten is a vertical member

Put log is a log placed transverse /

perpendicular to the wall

18. Ans: (c)

Sol: The correct sequence of preservative based

on its effectiveness is

Pressure impregnation: All the voids by

pressure are filled by preservatives.

Dipping: by gravity voids are filled by

preservatives.

Brushing or spraying: only surface is

treated by preservatives.

19. Ans: (b)

Sol: Star shakes:

20. Ans: (c)

Sol: A well seasoned piece of wood should on

other hand contain only 10 to 12 percent

moisture.

An important object of seasoning is to dry

the timber to the equilibrium moisture

content before use, so that gross

dimensional changes through shrinkage,

which inevitably occurs in green wood as it

tends to attain equilibrium with the

surrounding atmosphere, are eliminated.

21. Ans: (b)

Sol: In tension load applied parallel to grains

will give higher strength.

22. Ans: (a)

Sol: Even though timber is a brittle material on

application of confining pressure, its

elasticity can be increased.

23. Ans: (a)

Sol: Linear shrinkage = 0.1 to 0.3

Radial shrinkage = 3 to 6 %

Tangential shrinkage = 7 to 12 %

Ratio of tangential shrinkage to the radial

shrinkage of wood = 3

7to

6

12%

24. Ans: (b)

Sol:

Perpendicular to the grains compressive

strength will be minimum

Star shakes

: 23 : Timber


25. Ans: (b)

Sol: Broad leaved trees (Deciduous trees like

teak wood) give hardwood.

Needle like or ever green trees(coconut)

give soft wood.

Hard wood and soft woods are relative

terms which give hardness or softness.

26. Ans: (d)

Sol: Knots are defects in wood sometime

associated with the starting point of

branches.

Knots, generally, reduce workability,

due to irregular texture of timber.

Reason is a wrong statement.

27. Ans: (a)

Sol: Soaking timber in Ammonium sulphate

increases its fire resistance. Fire resistant

timber is also called refractory timber

28. Ans: (b)

Sol: Fibre board is a type of engineering wood

product that is made of wood fibres.

Adhesives like urea-formaldehyde (UF) (or)

Phenolic- formaldehyde resins (PF) are used

for attachment with high pressure.

This includes particle board, medium

density fibre board (MDF) and hard board.

Applications:

1. Sound proofing

2. Structural sheathing

3. Low slope roofing

29. Ans : (c)

Sol: Increasing order of the effectiveness of

timber preservatives.

Brushing: only surface is protected

dipping, only top layer is protected

Soaking in open tank: most of the parts of

wood are protected.

Pressure application: All the minute pores

are filled with preservative and protects

timber more effectively.

30. Ans: (d)

Sol: Cupping: Unequal shrinkage in radial &

tangential directions cause the wood to form

a cup.

Bowing: Bending in the form of a bow. Due

to irregularities in the board can be

eliminated by proper stacking while

seasoning.

Chucks: Splits at the end of boards due to

rapid drying.

Knots: Circular form of fibres due to

cutting of limbs (or) branches of a tree on

main stem.

31. Ans: (a)

Sol: Maximum deflection of timber beams ≯

span/300.



32. Ans: (a)

Sol: Deciduous trees shed leaves in autumn,

have hard wood, which can be used in

engineering practices.

Coniferous, ever green trees, yield soft

wood.

Wet rot: This is due to cellar fungus

(Coniophora puteana).

Wet rot fungi obtain food by breaking

down the walls of wood cells resulting in a

loss of strength of wood.

These fungus are not destructive as dry rot

but spreads in wet area.

Timber affected by wet rot will feel spongy

and look darker than surrounding timber.

When dry timber can crumble and crack

into finer particles.

33. Ans: (a)

Sol: Dry rot or brown rot is a disease due to

fungal (Serpula Lacryans) effect. White

powder develops on the surface of wood.

Dry rot is not due to decomposition of

wood. Dry rot is most serious problem in

timber. This can spread and destroy timber

seriously. Dry rot occurs in dried timber of

ships (or) buildings and caused by internal

fermentation or decomposition.

34. Ans: (b)

Sol: Well seasoned timber to be used for

engineering purposes, should have moisture

content around 10 to 12%

35. Ans: (d)

Sol: A wet winter followed by warm summer is

the ideal conditions for the growth of dry

rot fungus also called as brown rot. Dry

rot needs air and very little moisture.

36. Ans: (b)

Sol: Creosote oil (coal tar) is impregnated into

timber with high pressure to prevent fungal

effect, Insect bite and rodent attack.

37. Ans: (a)

Sol: In tropical countries like India hard wood is

obtained from deciduous trees. Which are

Broad leaved trees (like teak wood) .

: 25 : Timber


38. Ans: (c)

Sol: Dry rot is due to improper ventilation .

Dry rot needs air and very little moisture.

Stacking in open areas causes dry rot

Dry rot is due to decomposition of wood by

fungus.

39. Ans: (a)

Sol: Student should remember these failure

modes.

40. Ans: (c)

Sol: Scantling: A piece of sawn timber, such as

rafter in a truss, that has a small cross-

section. For rafters strong (Heart) wood is

used.

Ply wood is used for paneling purpose,

in partitions, flooring etc.

Laminated timber is used in arches/

trusses

Fiber boards are of medium density.

They are used for insulation electrical

boxes.

41. Ans: (d)

Sol: Heart shakes: Widest at the centre and

diminishing towards outer circumference

(A-4)

Knot: Damaged branch of a tree, which

causes twists in the grain arrangement.(B-3)

Dry rot and wet rot are due to fungal

effects (C – 1)

42. Ans: (c)

Sol: Dry rot is very aggressive when wood is

stored in a place where air circulation is

very high and the wood is subjected to

alternate dry and wet seasons.

43. Ans: (a)

Sol: Maximum tensile strength of wood can be

obtained by applying tensile force parallel

to grains.

44. Ans: (d)

Sol: Kiln seasoning of timber reduces density by

removing excess moisture, therefore, no

shrinkage or warping when it is used for an

engineering purpose. The life of timber

increases due to kiln seasoning.

45. Ans: (b)

Sol: Cambium layer is situated between inner

bark and sap wood.

46. Ans: (c)

Sol: Creosote is a purified coal tar. It is a good

preservative for timbers when used under



soil. The timber treated by creosote losses

its appearance.

Becomes black in colour.

It is effective in preventing fungus, Insect

and Rodent attack.

47. Ans: (a)

Sol: Tensile strength of timber is maximum when

tensile force is applied parallel to the grains.

48. Ans: (b)

Sol: Babul: Agricultural instruments, bullock

cart wheels, tool handles etc (A – 3)

Mulberry: Hockey sticks, tennis rockets

etc (D-1)

49. Ans: (c)

Sol: Teak wood is the best for furniture work.

Which takes good polish and easy to carve

also.

50. Ans: (c)

Sol: Timber is a homogeneous and orthotropic

material.

Homogeneous: Material. A material of

uniform composition throughout that cannot

be mechanically separated into

different materials.

Orthotropic: Materials have material

properties that differ along three mutually-

orthogonal axes.

51. Ans: (a)

Sol: Alignment of layers of wood is an important

factor for acquiring shear strength.

52. Ans: (c)

Sol: Differential shrinkage of timber causes

warping of timber.

53. Ans: (a)

Sol: Due to seasonal change in moisture content

of timber, its dimensions may change.

While fixing dimensions of the window or

door shutters proper tolerances should be

considered.

54. Ans: (a)

Sol: Pith: inner most portion of the trunk of a

tree (A-1)

Cambium layer: The layer between sap

wood and inner bark (D-4)

55. Ans: (d)

Sol: Fiber saturation point (FSP): The

moisture content at which all of the free

water is removed - the cell cavities are

empty - but the cell walls are still

completely saturated.

This is a key concept in wood design since

moisture affects the physical and

mechanical properties of wood

56. Ans: (b)

Sol: For building frames moisture content can be

upto 12%

: 27 : Timber


57. Ans: (a)

Sol: Due to Dry (Brown) rot: Sapwood is

attacked by fungus.

Wet rot: Damage of wood fibres due to

chemical decomposition of wood.

Grey rot: Destruction of cellulose into

grey colour due to fungal attack.

White rot: Destruction of lignin (an

amorphous, cellulose like, organic

substance which acts as a binder for

cellulose in wood and adds strength and

stiffness to cell walls) due to fungal attack.

58. Ans: (c)

Sol: 2to1E

E

transverse

allongitudin

59. Ans: (b)

Sol: Modulus of Elasticity of timber

Group A > 12.5 kN/mm2

Group B 9.8 – 12.5 kN/mm2

Group C 5.6 – 9.8 kN/mm2

60. Ans: (b)

Sol: To make timber fire resistant Sir Abel’s

process is adopted. In this process lime and

sodium silicate are used.

ASCU treatment is used to preserve timber

using Arsenic upper sulphate solution.

Creosoting is mixture of coal tar chemical

used to preserve timber against fungus and

insects.

Tarring, is also used in preservation of

timber tar is sprayed on timber.

61. Ans: (b)

Sol: Rueping process: is used to preserve wood

with the use of minimum amount of coal

tar. Creosote by alternating pressure and

vacuum so that only the walls of the wood

cells are coated and cells themselves are not

filled.

Lawry process: The preservative is forced

into the wood under pressure. The air inside

the wood then expands when the pressure is

released causing excess preservative to be

forced out of wood.

Full-cell process/Bethell process:

In this process wood is sealed in a pressure

chamber and vacuum is applied in order to

remove moisture from the wood cells. Then

pressure is applied with preservatives in

order to inpregnate the full wood cells. Coal

tar substances such as creosote, oil based

chemicals such as penta chlorophenol

(PCP) are used as preservatives. In this

process chemical is completely filled in

cells and slowly dry down. Therefore, high

quantity of preservative is required.

Empty cell process: Are of two types

1. Rupeing process 2. Lawry process

In these process the cell layers are coated

will chemicals and the chemical in cell

space is removed less chemical is required.



62. Ans: (b)

Sol: Cambium layer is located between inner

bark and sap wood.

Heart wood is strong wood, where

nutrients are not transferred, which gives

strength only. Therefore heart wood is most

suitable for construction work.

Cambium layer, infact, lies between inner

bark and sap wood. The cambium creates

cells that eventually become bark on outside

and cells that add to the sap wood

( Statement 1 is wrong)

Heart wood: The older, harder and

nonliving central wood of trees that is

usually darker, denser, less permeable, and

more durable than surrounding sap wood.

The best timber for construction is obtained

from heart wood. Heart wood supports the

tree. ( Statements 2 and 3 are correct).

63. Ans: (a)

Sol: In ply-wood grains of different layers are

arranged in such away that tensile strength

in mutually perpendicular directions must

be the same. Appropriate answer is (A).

64. Ans: (b)

Sol: Tensile strength is maximum in the

direction parallel to gains.

65. Ans: (d)

Sol: For a beam main important character

required is strength followed by stiffness or

toughness. There is no need to achieve

smooth finish in beam, except in case of

architectural buildings.

66. Ans: (a)

Sol: Dry rot is due to fungal attack.

Brown rot generally occurs in coniferous

(soft) wood is also due to fungal attack.

Dry rot is due to drying and wetting in the

open air.

67. Ans: (d)

Sol: Fiber saturation point (FSP): The

moisture content at which all of the free

water is removed - the cell cavities are

empty - but the cell walls are still

completely saturated.

This is a key concept in wood design since

moisture affects the physical and

mechanical properties of wood

69. Ans: (b)

Sol: Hard wood doesn’t have distinct annual

rings.

70. Ans: (d)

Sol: specific gravity of wood is around one. It

depends on species of timber.

: 29 : Timber


71. Ans: (c)

Sol: Annular rings on heart wood indicates age

of the tree.

72. Ans: (d)

Sol: Proper seasoning of timber will not effect

strength. It increases durability.

73. Ans: (b)

Sol: Plywood: lining of form-work in concrete.

Fibre board: Insulation

Laminated timber: Cantilever arches

(generally for Arches/ trusses)

Commercial block board: Furniture

74. Ans: (d)

Sol: Planks sawn from trees with twisted fibres

are not stronger

75. Ans: (a)

Sol: Timber from coniferous trees will have

distinct annular rings and straight grains

(like bamboo, coconut) they can be used as

tension members.

76. Ans: (b)

Sol: Drauxiness: Defect in timber, to cambium

layer due to fungal attack. This can be

identified by white spots on timber.

Foxiness: This defect is indicated by red or

yellow tinge in wood or reddish brown

stains or spots round the pith of tree

discolouring timber. This is due to poor

ventilation during storage or by timber.

77. Ans: (b)

Sol: Excrescences are the upsets or irregularities

appear on the body of timber.

The wood can be used for engineering

purposes by removing defected part of

wood.

78. Ans: (b)

Sol: Abel’s process is used to make timber fire

resistant. (Repeated. ESE, 2009)

79. Ans: (a)

Sol:

Dry rot is due to fungal attack. Humid and

dry atmospheric conditions cause dry rot.

Dry season after rainy season is the best

season for growth of fungus.

Dry rot is not related to termites.

No surface strips are formed.

80. Ans: (b)

Sol: Alternate wetting and drying decreases

durability. (Statement -3 is wrong).

81. Ans: (c)

Sol: IS code is used for classification of timber

for seasoning purpose IS 1141 – 1958.

(Memory oriented question)



82. Ans: (c)

Sol:

Preservatives increases life span of timber

(which preserves timber to last for a long

time)

Strength is a property of timber, which

can not be altered by preservatives.

Improper preservation reduces strength.

Preservative cannot reduce moisture.

Seasoning removes moisture.

Preservatives kills fungus, borers,

thermites etc and gives long life.

83. Ans: (b)

Sol: In plywood grains should be perpendicular

to each other to increase stiffness and

strength.

84. Ans : (d)

Sol: ASCU powder consisting of

Arsenic pentoxide (As2O5 2H2O) 1 part

Copper sulphate (CuSO4 5 H2O) : 3 parts

Potassium dichromate (K2 Cr2O7) : 4 parts

6 Parts of ASCU with 100 parts of water is

mixed to get ASCU solution.

86. Ans: (d)

Sol: Wood obtained from conifers is mostly soft

wood which doesn’t possess strength to be

used for commercial purposes.

87. Ans : (a)

Sol:

Seasoning of timber removes moisture

from sap wood therefore, wood becomes

dimensionally stable

Shrinkage, warping of wood will be

minimum.

88. Ans: (b)

Sol:

In select grade timber defects are not

allowed.

In select grade strength should be

uniform. It has sleek, uniform, and clean

appearance.

For earthquake design the strength

modification factor is 1.33.

89. Ans: (a)

Sol: ASCU treatment cannot enhance hardness

or density of wood. Therefore there is no

enhancement to strength.

Statement -4 is false

The only option without (4) is (a)

90. Ans: (c)

Sol: White rotting of timber gases emitted are

carbonic acid and hydrogen.

91. Ans: (a)

Sol: Cambium layer occurs between inner bark

and sap wood.

: 31 : Timber


92. Ans: (b)

Sol: Improper seasoning causes splitting of

timber. Seasoning is required to reduce

moisture in timber and to make it as

structural use. Both the statements are

individually true no relation between each

other.

93. Ans: (b)

Sol: Hardwood is non porous. It is dense.

Statement-2 is wrong.

94. Ans: (a)

Sol: ‘Compreg’ timber, pressed with resins, has

high specific gravity and having higher

strength.

The higher strength is achieved by

impregnation of resins.

95. Ans: (a)

Sol: Air seasoning takes a long time but it yields

durable, tough and elastic timber. Therefore

statement-1 is true, statement-2, explains

and supports statement-1

ACE Prelims CIVIL... · Foreword UPSC Engineering Services in Civil Engineering Volume - I...

Documents

Transcript of ACE Prelims CIVIL... · Foreword UPSC Engineering Services in Civil Engineering Volume - I...