structures

Question 1

dead load and live load

Answer 1

dead load and live load
dead loads
are permanent static loads on a structure that remain relatively constant overtime.
example: weight of the structure itself, beams, walls.

love loads are produced by the occuoancy

Question 2

cold form sections

Answer 2

sreel sheets.
They are of extremely thin profiles.
Probles
1.2mm, 2mm, 3mm.
-
example
:
angle iron
c section
“Built up sections” are made up from two or more or hot rolled sections exclusively.
cold formed
They are made by means of connecting them.

Question 3

lateral torsional buckling

Answer 3

lateral torsional buckling
This occurs when the load applied on the flexural member causes it to displace laterally and twist.
The displacement occurs due to the magnitude of the applied load and the twisting occurs if the
torsional Stiffness of the member section is insufficient applied. If the member u
In comparison to the load
Us more prone to lateral torsional buckling, it has a
smaller flexural capacity: the member will fail eavily. The member is prevented from developing is full
flexural strength.

Question 4

cavity walls

Answer 4

A Two single leat walls built with a gap
in-between.
I act as one wall
m
There are Steel ties built into them, tying them together - Cavity ties.
-
3. Cavity ties should be provided at Spacing go 900mm horizontally & 28450mm vertically

4* Each single leat wall can be of a different thickness

These walls have better thermal and acoustic insulation

Question 5

faced walls

Answer 5

Faced wall
a faced wall is a wall built of two different material
It is structurally treated as abre same thickness wall
built with weaker material.

Question 6

factors affecting the strength of a slender wall

Answer 6

All Factors pertaining to short walls (In the Same way)
2) Number and Sizes of Caps at the edges off Mostar joints. ↑ ↓
I
3) Lateral Load on wall (wind etc.) ↑ ↓

Question 7

strength properties of timber

Answer 7

Tension Parallel to grain.
Bending Parallel to grain.
Compn // grain
Compn perpendicular grain
Shear // Grain
Modulus of Elasticity.
Perpendicular

Question 8

factors affecting the strength properties of timber

Answer 8

Moisture in Timber
2) Growth characteristics.
3) Duration of Load
4) Size & Shape of Member

Question 9

models of failure of solid timber flexural members

Answer 9

Splitting of Bottom Fibre
2) Lateral Torsional Buckling.
3) Shearing along Grain.
Members
4)Bearing at supports at concentrated loads
5)deflection

Question 10

fiber saturation point

Answer 10

When Timber starts drying first the free moisture is evaporated Ones the total amounts of free moisture is evaporated, the timber has reached the Fiber Saturation Point

When timber dries further than “Fibre Sat point”,”
*Strength proporties will increase Incect or fungal attacks will decrease

at this point the moisture Content is about 25% - 30%
Only the bound moisture is present
timber will not have any reduction in vol

Question 11

cellular walls

Answer 11

The stiffness of a cellular wall is greater since the overall thickness is more and slenderness is less

It has more strength for a Smaller amount of material

Question 12

factors of affecting the load transfer capacity

Answer 12

nail joints

diameter of nail Penetration of head point
Penetration of point side
Strength class of timber
Number of nails.
*hammered into Joints
*Clean Shaft and point

screw joints
Should be inserted perpendicular
to grain
Point Side penetration -2x
Number of screw.
Strength Class of timber.
*transfer Shear load as well
as withdrawal loads.
* driven into joints.

Question 13

Why is timber Considered as an hygroscopic and an isotropic material.
2020/

Answer 13

hygroscopic material - Possesing the ability to absorb and Shred water from a Environment

isotropic-

Proportis of timber material does depend on direction. Unlike steel which ever the direction you take strength properties remain the same

Question 14

timber seasoning

Answer 14



Timber Seasoning
I brought downto equilibrium moisture contenter this process. is called timber seasoning.
Go air dried.
kiln.
* timber treatment is to make sure that it’ll not decay, not attacked by insects, fungi.
local timber -graded into a grades

Question 15

method of treating timber

Answer 15

method of treatment.
1 Brush application / Sprayru 2) Open tank method
3) Hot & Cold Tank method. 9) Pressure Treatment

Question 16

Wood Based Products.

Answer 16

Wood Based Products.
1 Particle Board -chip bearch.
a) Fibre Board (you can’t see particles in this
high
MDF, HDF.
(medium
-3) Ply wood
density fibre
t
Built-up Sections
3) Laminated Timber-

Question 17

advantage of plywood

Answer 17

advantage of plywood
* you have grains running in both directions, good strength in both directions.
* Cost effective.

Question 18

why masonary walls should not be subjected to bending moments, unless accomplained with a sufficient Compressive load.

Answer 18

Masonary is generally very good in resisting compression has good Compressive strength…

However it is weak
when subjecte to tensile strength.

If a masonary wall is axially loaded and there is a chance of it built buckling and falling, as it will be in both tension and compression

Since masonary is poor in bending and tension, the wall will crack (assuming that self weight is 2000)
axial Toad
If theres the wall was an elastic material & the Stress
distribution will be (draw)
له
any element subjected to compression can buckle and it is one mode of faliure

Tension develops and then the wall.
fails

Tention develops on the inner curve of the “Column and Cashing develops so the wall fails due to buckling & Crushing.

Question 19

effective thickness

Answer 19

its not the actual thickness of the wall its effective thickenss depebds on varius factors such as

Factors affecting effective thickness.
Coefficient of stiffness (K)
thickness of wall (t).
gap between Piers from center to center (SP)
(4 breadth of pier (bp).
Thickness of wall with Pier (tp)

How effective thickness varies with thos factors
(K) increases (+) EFincreases ↑
(SP) increases. EF (bp) increases t
(TP) increases

BASICALY WHEN ALL THIESE INCREASE ET INCRESE

Question 20

Why 2 different PFOS is applied for love load and dead load

Answer 20

Pfos dead load= 1.4
PFOS live load= 1.6
Live loads create uncertainty due to its variance therefor it requires higher PFOS comp dead load which certain and can be calculated accurately

Question 21

Slenderness ratio

Answer 21

When slenderness ratio increases the tendency to buckleup increases

Question 22

Factors effecting the strength of slenderwalls

Answer 22

1.Slenderness ratio of the walls
2.Gaps in the edges of the wall
Due to shrinkage and workmanship motabed dsnt continue right throughout the bed
Lateral loads (wind load) acting on the load increases the weaker the wall

Question 23

Glu laminated timber

Answer 23

Glu large number of thin planks which is horizontal or vertical laminated, glu planks in the grain directing the longitudinal direction

Question 24

Adv laminated timber

Answer 24

Larger cross sections are possible by stacking on top of each other

Larger longer members by gluing and by vertical joints shouldn’t coincide

Better quality timber
By removing deflect and gluing the planks again

Efficient sections

By the top and bottom most plank has a strong variety of timber middle weaker timber where the stresses are low. Aka selective layering

Weaved members are possible
Grains to the longitude axis there for stronger

Easy cheap to treat

Question 25

Why masonry walls should not be subjected to bending moments unless accompanied by sufficient compressive loads

Answer 25

Masonry good atresistong compression not at tension/tensile strength

If axialy loaded it may buckleup and fail in both tension and compression

Since it’s poor at bending and tension it will Crack

Under compression ot will buckleup

Tension develops on the inner curve the column crushing develop and the walls fail.

Question 26

Modes of failure of solid timber flexual members

Answer 26

Splitting of bottom fibers
Tensile strength affected over the allowable stress the bottom fibers splits

Lateral torsional buckling
Bottom fibers stays straight while the top fibers buckle causing the timber to twist
Sjear along the grain
Timber is weak in the horizontal shear.
Timber is strong g on the horntal shear

Deflection (draw)

Bearing at supports at co centrated loads

Question 27

Moisture content

Answer 27

%of water contained in timber

Moisture cont= weight if water in timber sample/ weight of water in dry timber sample × 100

moisture will! The strength of the timber and will decay
As it’s subjected to seasoning

Question 28

Fiber saturation point

Answer 28

When timber starts drying first free moisture evaporated (water inbetween the cells draw)

When evaporated ot reaches its first evaporated point. The moisture content is 25-30%

Only bind moisture remains( moisture inside the cell)

Timber will not have any reduction in volume, strength proposes increases. Insect and fungi attacks will decrease.

Question 29

Equilibrium moisture content

Answer 29

When u further dry timber than bond moisture will start to evaporate then timber cell tubes will contract and the volume of the timber will reduce.

Below fiber saturation point it will reach the moisture content. This os where we use are timber structuraly

Moisture content is 8-20%

Question 30

Factor effecting the strength properties of timber

Answer 30

Moisture in timer
Growth characteristics of timber- slope of grains , knots and waves

Duration of loads

Size and shape of timber

Question 31

Hudroscopic

Answer 31

Possessing the ability to absorb and shed water from env to the env

Question 32

Composite slabs

Answer 32

Precast + insitu cast
AdV

Insitu conc= pured to obtain the thickness to woth hold the load

Lighter oannels easy to transport and cheaper
Form work not needed pre cast pannel act as a deck

Series of simply supported pannels

Question 33

Pre stressed concrete advantage

Answer 33

Small ant of construction material

Longer soan and length can be achieved

Few joints needed than traditional RC there low maintenance

Reduce the formwork as multiple uses of formwork is possible

Rapid construction with better quality

Requires small amt of construction materials

Question 34

DISADVANTAGES OF PRE STRESSED CONCETE

Answer 34

REQUIRE HIGHER strength concrete amd higher Tensile strength

Requires additional special equipment like Jackson and Anchorage
Concrete pretending requires skilled technology and high skill workers

Higher construction cost than RCC

Question 35

Role of reinforcement on a concrete beam

Answer 35

Reinforcement are designed to carry transverse external loads,

Loads cause bending shear and tortion across their lenth

Concrete stronger in compression not jn tension

Steel reinforcement is to take Tensile stress of the reinforce concrete

Question 36

Safe bearing capacity of soil

Answer 36

Dense soil has high bearing capacity
Loose clay has low bearing capacity
Peat has no bearing capacity
Normal soil has a about 100m

Geotypicak surveys are dine to find the soil properties msucj a s the bearing capacity.
Most typical foundation is pad footing provided separately for each column

And the column are categorized into shallow and deep foundation