The civil structure

Difference between Prismatic Compass and Surveyor Compass

noreply@blogger.com (The civil structure) — Tue, 26 Sep 2023 22:07:00 +0530

Difference between Prismatic Compass and Surveyor Compass

Prismatic Compass and Surveyor's Compass are two different types of compasses used in surveying for measuring angles and bearings. They have distinct characteristics and applications:
Prismatic Compass:
Design: The prismatic compass is a simple and compact compass with a prism attached to it.
Use: It is primarily used for measuring magnetic bearings (angles relative to magnetic north) and is well-suited for reconnaissance surveys, preliminary surveys, and rough traversing.
Accuracy: Prismatic compasses are generally less accurate compared to surveyor's compasses and are suitable for less precise work.
Features: Prismatic compasses often have a sighting mechanism with a peephole and a hairline to aim at the target.
Portability: They are lightweight and easy to carry, making them suitable for fieldwork.

Surveyor's Compass (or Transit Compass):
Design: Surveyor's compasses are more sophisticated and precise instruments. They consist of a magnetic compass needle and an alidade (a sighting device) mounted on a graduated circle.
Use: They are used for measuring both magnetic bearings and angles in relation to true north. Surveyor's compasses are essential for more accurate land surveys, boundary marking, and topographic mapping.
Accuracy: These compasses are designed for high accuracy and can provide precise angle measurements.
Features: Surveyor's compasses often include additional features like vernier scales for more accurate readings, bubble levels for leveling the instrument, and sometimes telescopic sights for precise targeting.
Portability: While surveyor's compasses are bulkier and heavier than prismatic compasses, they are still portable enough for most field surveying tasks.

In summary, prismatic compasses are simpler, lightweight instruments suitable for less precise work and quick measurements, while surveyor's compasses are more complex and accurate instruments used for detailed land surveys and mapping tasks. The choice between them depends on the specific requirements and accuracy needed for a given surveying project.

Sludge disposal amd management

noreply@blogger.com (The civil structure) — Sat, 5 Dec 2020 14:42:00 +0530

Sludge disposal: -

Abstract :-

Sludge management is one of the most difficult and challenging tasks of wastewater treatment plants due to its high water content and poor dewaterability and strict regulation for sludge reuse or disposal. One of the recent goals of wastewater treatment plants is to develop more environmentally friendly processes to reduce the volume of sludge for disposal and to convert sludge into bioenergy. Energy recovery of the sludge generally includes the conversion of the sludge into biogas, syngas, and bio-oil which can be further converted into electricity, mechanical energy, and heat. In this chapter, methods for energy recovery from wastewater sludge in the forms of bio-oil and biogas are reviewed. An overview of different sludge types and the common methods for measuring their characteristics and bio-oil production from sludge through hydrothermal treatments are discussed. Hydrothermal treatment reaction pathways and the effects of various operating parameters such as reaction temperature and time, the presence of a catalyst, feedstock type, water-to-biomass ratio, and water at sub −/supercritical conditions are discussed. In addition, some available hydrothermal processes in pilot or demonstration scales are introduced. Biogas production from sludge through anaerobic digestion is also reviewed, and effects of various pretreatment methods such as thermal, chemical, thermochemical, and mechanical treatments on the anaerobic digestion performance and the final biogas yield are discussed. Furthermore, the established and emerging technologies for each pretreatment method are introduced.

Introduction

Sludge disposal :- The solids that result from wastewater treatment may contain concentrated levels of contaminants that were originally contained in the wastewater. A great deal of concern must be directed to the proper disposal of these solids to protect environmental considerations. Failure to do this may result in a mere shifting of the original pollutants in the waste stream to the final disposal site where they may again become free to contaminate the environment. A more reasonable approach to ultimate solids disposal is to view the sludge as a resource that can be recycled or reused.

All the sewage sludge produced at a treatment plant must be disposed of ultimately. Treatment processes such as have been described may reduce its volume or so change its character as to facilitate its disposal, but still leave a residue which in most cases must be removed from the plant site. Like the liquid effluent from the treatment plant, there are two broad methods for the disposal of sludge - (1) disposal in water, and (2) disposal on land. This applies regardless of whether or not the sludge is treated to facilitate or permit the selected method of disposal.

Methods for sludge disposal :-

Disposal in water :- This is an economical but not common method because it is contingent on the availability of bodies of water adequate to permit it. At some seacoast cities, sludge either raw or digested is pumped to barges and carried to sea to be dumped in deep water far enough off shore to provide huge dilution factors and vent any ill effects along shore.

In the past few years there has been an increased problem of pollutional loads, well above safe standards, affecting the south-shore beaches on Long Island, facilitating the closing of the beaches to the public. Some of these pollutional loads have been attributed to sludge deposits coming to shore form off-shore ludge barging operations. Where barged to sea, the value of some treatment such as thickening or digestion, depends on the relative cost of the treatment and savings in cost by barging smaller volumes, or the value of gas produced by digestion.

Land filling:- A site for the disposal of waste materials by burial and is the oldest form of waste disposal.

Some landfills are also used for waste management purposes, such as the temporary storage, consolidation and transfer, or processing of waste material (sorting, treatment, or recycling).

Problem with this method is that many landfills are filling up, and towns are having trouble finding places to put new ones.

(3) Composting :- Composting can be defined as the aerobic thermophilic decomposition of organic wastes to a relatively stable humus. Decomposition results from the biological activity of microorganisms which exist in the waste. A good compost could contain up to 2 percent nitrogen, about 1 percent phosphoric acid, and many trace elements. Its most valuable features, however, are not its nutrient content, but its moisture retaining and humus forming properties. Many types of microorganisms are involved in converting the complex organic compounds such as carbohydrates and proteins into simpler materials, but the bacteria, actinomycetes, and fungi, predominate. These organisms function in a composting environment that is optimized by copying the natural decomposition process of nature where, with an adequate air supply, the organic solids are biochemically degraded to stable humus and minerals. Compost is generally considered as a material to be used in conjunction with fertilizer, rather than as a replacement for fertilizer unless it is fortified with additional chemical nutrients.

Compost benefits the soil by replenishing the humus, inmproving the soil structure, and providing useful nutrients and minerals. It is particularly useful on old, depleted soils and soils that are drought-sensitive. In horticulture applications, compost has been useful on heavy soils as well as sandy and peat soil. It has been commonly applied to parks and gardens because it increases the soil water absorbing capacity and improves the soil structure.

Parameters: All composting processes attempt to create a suitable environment for thermophilic facultative If the environmental conditions for biological aerobic microorganisms. decomposition are appropriate, a wlde variety of organic wastes can be composted. The most important criteria for successtul composting are:

(a) complete mixing of organic solids,

(b) nearly uniform particle size,

(d) proper moisture content,

(e) proper temperature and pH, and

(f) proper carbon-nitrogen ratio in the raw solids.

(4) Other methods :-

Ocean Disposal - Dumping or controlled release of sewage sludge from a barge or other vessel into marine water.

Distribution and Marketing - The give-away, transfer, or sale of sewage sludge or sewage sludge product in either bagged or bulk form.

Surface Disposal - A controlled area of land where only sewage sludge is placed for a period of one year or longer. Sludge placed in this area is not provided with a daily or final cover.

CONCLUSION:-

Nothing is waste until you cannot use it anymore in anyway! At one time, wastes piled up and people did not think deep enough on how to use them. Today, it is gratifying to see the innovations in waste management - recycling wastes into usable products, generating methane for fuels, manufacturing new products for home/commercial usage such as fence posts, furniture… the list goes on. These are conclusions for waste management most important being ‘promoting brain power.’

(Thanks you)

Concrete vibrators

noreply@blogger.com (The civil structure) — Sun, 22 Nov 2020 09:58:00 +0530

CONCRETE VIBRATORS:-

Following are the four types of vibrators:-

1. Internal Vibrators:-

These vibrators consist of a metal rod which is inserted in fresh concrete.
Skilled and experienced men should handle internal vibrators. These vibrators are more efficient than other types of vibrators.

2. Surface Vibrators:-

These vibrators are mounted on platform or screeds.
They are used to finish concrete surfaces such as bridge floors, road slabs, station platform, etc.

3. Form Vibrators or shutter vibrators:-

These vibrators are attached to the formwork and external centering of walls, columns, etc. The vibrating action is conveyed to concrete through the formwork during transmission of vibrations. Hence they are not generally used.
But they are very much helpful for concrete sections which are too thin for the use of internal vibrators.

4. Vibrating Tables:-

These vibrators are widely used for making precast products. It is used for prestressing and concrete specimens

Period of Curing:- The curing period is about 7 to 14 days.

Deep foundation

noreply@blogger.com (The civil structure) — Fri, 20 Nov 2020 16:17:00 +0530

DEEP FOUNDATIONS :-

These foundations carry loads from a structure through weak incompressible soils or fills

on to the stronger and less compressible soils or rocks at depth.

These foundations are in general used as basements, buoyancy rafts, caissons, cylinders, shaft and piles

Basements:- They are constructed in place in an open excavations. They are hollow substructures designed to provide working space below ground level.
Buoyancy Rafts:- They are hollow substructures designed to provide a buoyant substructure beneath which reduce net loadings on the soil to the desired low density.
Caissons:- They are hollow s8ubstructures designed to be constructed on or near the surface and then sunk as single units to their required level.
Cylinders:- They are single small cell caissons.
Shaft Foundations:- They are constructed within deep excavation supported by lining constructed in place and subsequently filled with concrete.
Pile Foundations:- The pile foundation is a construction supported on piles. A pile is an element of construction composed of timber, concrete or steel or a combination of them. The piles may be placed separately or they may be placed in form of a cluster throughout the structure.

Classification of piles:

1. Classification based on function: Bearing Pile, Friction Pile, Screw Pile, compaction

Pile, Uplift Pile, Batter Pile and Sheet Pile

2. Classification based on materials and composition: Cement concrete piles, Timber

piles, Steel piles, Sand Piles, and Composite piles.

Click here for Raft foundation

Sand replacement method

noreply@blogger.com (The civil structure) — Thu, 19 Nov 2020 16:51:00 +0530

SAND REPLACEMENT METHOD :-

Used in case of hard and gravelly soils.
A hole in ground is made.
The excavated soil is weighed.
The volume of hole is determined by replacing it with sand.
Insitu unit weight is obtained by dividing weight of excavated soil with volume of hole.

RAFT FOUNDATION

noreply@blogger.com (The civil structure) — Fri, 24 Jul 2020 14:15:00 +0530

RAFT FOUNDATION :-

Raft foundation is generally a thick

concrete slab resting on a large area of

soil reinforced with steel rods and is

used to support columns or walls and

transfer loads from the structure to the

soil.

Raft foundation may be used under the
following conditions:

1 .The soil has a low bearing capacity.

2. Load of the structure has to be

Distributed over a larg area.

3. Individual or any other foundation area would approximately cover 50% of the

total ground area beneath the

structure.

2.The columns or walls are placed so

closely that the individual footings

would overlap.

3. Stress on the soils needs to be reduce.

4. There is a possibility of differential settlement in case individual footing is used.

5. When soil strata are unpredictable and contain Pockets of compressible soil.

6. The basement is to be constructed.

7. Any other type of footing cannot be

used advantageously.

Methods of Plane Table Surveying

noreply@blogger.com (Dushyant Chourke) — Fri, 10 Jul 2020 15:15:00 +0530

METHODS OF PLANE TABLE SURVEY

• Different operations are involved during the location of details through plane table surveying.

• To carry out the operations under different field conditions, different methods of plane table surveying have been evolved –

1. Method of Radiation

2. Method of Intersection

3. Method of Traversing

4. Method of Resect

• The method of radiation and the method of intersection are employed to locate objects and features present in the area of survey.

• The method of traversing is used to plot the network of stations and the method of resection is employed to determine and to plot the location of the plane table as well as to orient the table simultaneously.

1. METHOD OF RADIATION

• In this method, instrument is set up

at a station and rays are drawn to

various stations which are to be

plotted.

• Then distances are cut on a suitable

scale after actual measurement.

• It is suitable for small area where all

the points are visible and accessible

from the station.

• The method is convenient if

telescopic or digital alidade is used.

Otherwise, it is effective when

associated with tacheometer or

EDM for measurement of horizontal

distance.

2. METHOD OF INTERSECTION

• In this method, locating of a point on

the drawing sheet is done by

intersecting two rays drawn from

two different stations.

• Also called as GRAPHICAL

TRIANGULATION.

• It is preferred when distance

between stations is very large and

stations are inaccessible and ground

is undulating

3. METHOD OF TRAVERSING

Let us consider the stations A, B, C and D

Stations are to be chosen in such a way

that adjoining stations are visible

With the alidade pivoted at a, draw the rays

to B and D. Distances AB and AD are

measured and plotted on the respective

rays, ab and ad respectively.

The plane table is then shifted to

station B, get it set and then

oriented by back sighting to

station A.

With the alidade pivoted at b, draw

a ray to C. Distance BC is

measured and plotted on the ray

as bc.

In this way, plane table is shifted to

stations C and D and corresponding

rays are drawn to obtain the plotting

of the traverse abcd.

• This method of plane table surveying is

used to plot a traverse in cases stations

have not been previously plotted by

some other methods.

• In this method, traverse stations are

first selected. The stations are plotted

by method of radiation by taking back

sight on the preceding station and a

fore sight to the following station.

• Here distances are generally measured

by tachometric method and surveying

work has to be performed with great

care.

4. Method of Resection

• It is the process of determining location of station occupied by the

plane table with reference to stations which are already plotted on the drawing sheet

a) Resection by Compass

b) Resection by Backsighting

c) Resection by 3 point problem

• In this method, three well defined points,

having locations already being plotted on

the drawing are involved. These are used to

find and subsequently plot the location of

the plane table station.

• if X, Y and Z are well defined objects

present in the field whose plotted positions

are x, y and z. Now, if the plane table is

oriented correctly, the three resectors Xx, Yy

and Zz get intersected at p which

represents the location of the plane table

station, P on the drawing sheet.

• in three point problem, if the orientation of the plane table is not proper, the

intersection of the resectors through the

three points will not meet at a point but

will form a triangle, known as triangle of

error

• The size of the triangle of error depends

upon the amount of angular error in the

orientation.

• In three point problem, orientation and

resection are accomplished in the same

operation.

• The trial and error method of three point

problem, also known as Lehman's method

minimises the triangle of error to a point

iteratively.

• The iterative operation consist of drawing

of resectors from known points through

their plotted position and the adjustment

of orientation of the plane table.

Definition of Pressure, density, specific weight, and gravity

noreply@blogger.com (The civil structure) — Wed, 8 Jul 2020 22:35:00 +0530

Pressure (P):

• If F be the normal force acting on a surface of area A in contact with liquid,then
pressure exerted by liquid on this surface is: P =F / A

• Units : N /m2 or Pascal (S.I.) and Dyne/cm2 (C.G.S.)

• Dimensions :-

• Atmospheric pressure:- Its value on the surface of the earth at sea level is nearly
1.01*10 5N/ m2 or Pascal in S.I. other practical units of pressure are atmosphere,
bar and torr (mm of Hg)

• 1atm = 1.01 *10 5Pa = 1.01bar = 760 torr

• Fluid Pressure at aPoint:- dP= dF/dA

Density ( ρ):

• In a fluid, at a point, density ρ is defined as: Mass/volume

• In case of homogenous isotropic substance, it has no directional properties, so is a scalar.

• It has dimensions [ML-3] and S.I. unit kg/m3 while C.G.S. unit g/ccwith
1g / cc = 10 3kg / m 3

• Density of body = Density of substance

• Relative density or specific gravity which is defined as :-

Specific Weight ( w):-

• It is defined as the weight per unit volume.

• Specific weight =Weight
Volume

Specific Gravity or Relative Density(s):-

• It is the ratio of specific weight of fluid to the specific weight of a standard fluid.

Standard fluid is water in case of liquid and Hidrogen gas or air in case of gas.

Specific gravity. =. Density 𝑜𝑓 𝐹𝑙𝑢𝑖𝑑
Density 𝑜𝑓 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝐹𝑙𝑢𝑖𝑑

Plane Table Surveying and its advantages and disadvantages

noreply@blogger.com (Dushyant Chourke) — Wed, 8 Jul 2020 18:51:00 +0530

Plane Table Surveying

• It is a graphical method of surveying in which field work and
plotting are done simultaneously

• It is mainly used for small and medium scale mapping (1:10 000 to
1: 25 00 000)

• Before starting plane table surveying, at first control stations are
established to cover entire area, then a suitable scale is decided

• After that surveyor starts collecting details from either of the
point and traverses all the stations

• Elevation of points of observation are determined with the help of
levelling, Indian Clinometer and telescopic alidade

Advantages of Plane Table Surveying

• It is suitable for location of details as well as contouring for large scale maps directly in the field.

• As surveying and plotting are done simultaneously in the field, chances of getting omission of any detail get less.

• The plotting details can immediately get compared with the actual objects present in the field. Thus errors as well as accuracy of the plot can be ascertained as the work
progresses in the field.

• Contours and specific features can be represented and checked conveniently as the whole area is in view at the time of plotting.

• Only relevant details are located because the map is drawn as the survey progresses.
Irrelevant details get omitted in the field itself.

• The plane table survey is generally more rapid and less costly than most other types of survey.

• As the instruments used are simple, not much skill for operation of instruments is
required. This method of survey requires no field book.

Disadvantages of Plane Table Surveying

• The plane table survey is not possible in unfavorable climates such
as rain, fog etc.

• This method of survey is not very accurate and thus unsuitable for large scale or precise work.

• As no field book is maintained, plotting at different scale require full exercise.

• The method requires large amount of time to be spent in the field.

• Quality of the final map depends largely on the drafting capability of the surveyor.

• This method is effective in relatively open country where stations can be sighted easily .

Limit State Method

noreply@blogger.com (Dushyant Chourke) — Wed, 8 Jul 2020 12:29:00 +0530

Limit State Method

• Limit state is the state at which the structure becomes unfit for use.

Two types of Limit states :

1. Limit state of Collapse

• Also known as Ultimate Limit State

• Adequate margin of safety shall be available for normal overloading

• This includes limit state of strength like overturning, sliding, buckling, fatigue, flexure, compression, etc

2. Limit State of Serviceablity

• Satisfactory performance under service load (deflection, crack, vibration, leakage, loss of durability, etc)

• If a structure has reached just before the limit state of serviceability and loads are removed, the structure

regains its original shape, however a structure achieving Collapse load can not recover its original shape and

dimension

Working Stress Method

noreply@blogger.com (Dushyant Chourke) — Wed, 8 Jul 2020 11:13:00 +0530

Working Stress Design

• Traditional method of design

• It is assumed that concrete is elastic

• Steel and Concrete together behaves elastically

• The basis of this method is that the permissible stress for concrete and steel are not

exceeded in any worst combination of working load

• The sections are designed assuming the materials obey Hooke’s law

Assumptions in Working Stress Method:

• A section which is plane before bending remains plane after bending

• Bond between steel and concrete is perfect within elastic limit of steel

• Tensile strength of concrete is ignored

• Concrete is elastic, i.e. stress in concrete varies linearly from zero at neutral axis

to a maximum at the extreme fiber

Drawbacks of Working Stress Method:

• Concrete is not elastic

• Difficult to account for shrinkage and creep in WSM

TURBULENT FLOW AND LAMINAR FLOW

noreply@blogger.com (The civil structure) — Sat, 11 Jan 2020 23:47:00 +0530

TURBULENT FLOW AND LAMINAR FLOW

Turbulent flow: That type of flow in which the fluid particles move in a zig-zag way or non uniform. In other words

In turbulent flow, fluid particles move in a random manner resuling in mixing of the
particles. Turbulent flow is possible at high velocities and when the fluid is less
viscous, in case of pipe flow.

Note : If R. >4000. flow is turbulent.

Laminar flow : Laminar word is derive from the word laminationt, which means one layer over other layers. In other words

The particle move in layers gliding smoothly over the adjacent layer.

Characteristics of laminar flow:

(i) low fluid velocity

(ii) Highly viscous

(iii) Flow is stream an parallel to each other so that to stream line does not intersect
each other.

Note : In case of pipe flow, if R <2000, flow is laminar.

SYMON'S NON RECORDING RAIN GAUGE

noreply@blogger.com (The civil structure) — Wed, 1 Jan 2020 19:31:00 +0530

SYMON'S NON RECORDING RAIN GAUGE

Standard non-recording
ingauge prescribed by the IMD is the Symon's raingauge.

The gauge consists of a funnel with a sharp edged rim of 127mm diameter, a
cylindrical body, a receiver with a narrow neck and handle and a splayed base swhich
is fixed in the ground.
The rain gauge should have a narrow-neck and should be sufficiently protected from radiation to minimize the loss of water from the receiver by evaporation.
To prevent rain from splashing in and out, the vertical wall of the sharp edgedrim ismade deep enough and the slope of ftunnel steep enough (at least
45°). The rain falling into the funnel is collected in the receiver kept inside the body and is measured by means of a special measure glass (supplied along with the gauge)
which is graduated in mm. The receiver has a capacity of 175 mm of rain. In regions of
heavy rainfall, raingauges with receivers of 375 mm or 1000 mm capacity may bei
used.
The measure glass has a capacity of 25 mm and can be read to nearest 0.1 mm. The
gauge is fixed on a masonry or concrete foundation of size 60 cm x 60 cn x 60 cm
which is sunk into the ground. Into this foundation the base of the gauge is cemented,
so that the rim of the gauge is exactly 30 cm above the ground level. The top of the
gauge should be perfectly horizontal.

ROAD ROLLER and their types

noreply@blogger.com (The civil structure) — Wed, 1 Jan 2020 19:00:00 +0530

ROAD ROLLER and their typs

Definition :- A road roller (sometimes called a roller-compactor, or just roller) is a compactor type engineering vehicle used to compact soil, gravel, concrete, or asphalt in the construction of roads and foundations. This typically only applies to the largest
:- examples (used for road-making).

This is most important for civil engineering construction.

TYPES OF ROLLERS:-

Depending upon the project requirement and soil to be compacted, different types of rollers are used for compaction work. The various types of rollers which are used for compaction are:

Sheep foot Rollers
Pneumatic tyred Rollers
Vibratory Rollers
Grid Rollers
Smooth Wheel Roller

The following types of road rollers are generally used.

(1) VIBRATORY ROLLERS:-

This type of roller is fitted with one or two smooth surfaced steel wheels 0.9 m to 1.5 m in diameter and 1.2 m to 1.8 m wide.
Self propelled vibratory rollers are now available weighing from 4 to 6 tonnes.
Vibrations are generated by the rotation of an eccentric shaft inside.
A vibratory roller is used for compacting granular base courses. It is sometimes used for asphaltic concrete work.

(2) GRID ROLLERS :-

These rollers have a cylindrical heavy steel surface consisting of a network of steel bars forming a grid with squire holes and may be ballasted with concrete blocks.
They are generally towed units and can operate at speeds between 5 and 24 km/h.
Typical weights vary between 5 tonnes net and 15 tonnes ballasted.
Grid rollers provide high contact pressure but little kneading action and are suitable for compacting most coarse grained soils.

(3) PNEUMATIC TYRED ROLLERS

This type of roller consists of a heavily loaded wagon with several rows of four to six closely spaced tyres. This is also called rubber tyred roller.
It provided uniform pressure throughout the width.

2 factors governing the amount of compaction are as follow

(1) Tyre pressure
(2) Area of contact

Tyre pressure may be upto about 7 kg/cm2
The coverage area is about 80%.
The gross weight of the roller is about 6 to 10 tonnes which can be increased to 25 tonnes by ballasting with steel section or other means.
The maximum density can be achieved by 8 passes of the roller. The optimum speed of roller is between 6 to 24 km/h.
Used for compacting cold laid bituminous pavements, soft base course materials or layers of loose soil. These rollers are also suitable for compacting closely graded sands, and fine-grained cohesive soils at moisture content approaching their plastic limits, though the compaction is not as high as that with the smooth wheel roller.

They are particularly efficient when used to finish off the embankment compacted by sheepsfoot roller or on loose sandy soils.

(4) sheep foot roller

These type of soil compaction equipment are most suitable for compacting fine grained soils such as heavy clays and silty clays. It can be used for compaction of soils in dams, subgrade layer in pavements and road construction projects. These rollers are also called tamping rollers.

Sheep foot roller consists of steel drum having many round or rectangular shaped lugs or foot on it. Different types of lugs or foot are namely spindle shaped with widened base, prismatic and clubfoot type. Different types of rollers are available having different diameters and widths of drum and different lengths and shapes of the lugs. The lugs size slightly varies from one sheepsfoot roller to another. Designing of the lugs of foots depend upon the specification and it varies from manufacture to manufacturers

Characteristics Sheepsfoot Roller:

The Ground coverage area of these roller is less. 8-12 % ground coverage under the lugs on drum.
Contact pressure up to 1400 to 7000 kpa.
Sheepsfoot roller work normally at speeds from 6-10 km/h.
Pressure on the feet may be increased by filling the drum with wet sand or some other material.
Mostly used for cohesive soils such as heavy clays and silty clays except for sandy soil.
Compactative efforts are static weight and kneading.
The thickness of compacting layer is kept minimum 5 cm or more, which depends on the length of foot.

(5) Smooth wheel roller

It is one of the field compaction equipment that comes under the category of heavy compaction equipment. It is otherwise named as smooth drum roller. The front side has one steel drum fixed along with one wheel, and the rear side has one or two wheel with drums which will not vibrate. When the rear side of the roller have only one wheel, then it is called as tandem roller. If the rear side has two wheels, then it is called as three-wheeled roller.

The size of rear side rollers is almost 6 feet in diameter and it is not more than two feet wide. The front side roller is smaller in diameter than that of the rear side.
It provides 100 percentage contact surface area under the roller, with the pressure in roller up to 400 kPa.
It is commonly used for finer aggregates, and silts. This is widely employed to do the rolling of the subgrade to a profile and compaction of asphalt pavement.

For doing the deep layer compaction in clay and sand, this equipment is not suitable. This is due to the reason that the empty voids in the soil cannot be minimised without the use of vibrators.

Click here for concrete vibrators.

Building material quiz and article about structure of a timber tree.

noreply@blogger.com (The civil structure) — Thu, 25 Apr 2019 14:26:00 +0530

STRUCTURE OF A TIMBER TREE:-

For building material quiz - go down

TIMBER DEFINITION :-

Timber is a type of wood which has been processed into beams and planks. It is also known as “lumber” in US and Canada. Basically, timber or Lumber is a wood or firewood of growing trees. Any wood capable of yielding a minimum dimensional size can be termed as a timber or lumber. It is a stage in the process of wood production. Timbers are used for the structural purpose. Those woods which are adapted for building purposes are timbers. Finished timber is supplied in standard sizes for the industry. Timber is used for building houses and making furniture.

CLASSIFICATION OF TREES:-

Trees are classified according to their mode of growth.

Following is the classification of trees:

1. Exogenous Trees: These trees increase in bulk by growing outwards and distinct consecutive rings are formed in the horizontal section of such a tree. These rings are known as the annual rings because one such ring is added every year and these rings are useful in predicting the age of the tree . The timber which is mostly used for engineering purposes is related to this category.

Exogenous trees are further subdivided into two groups.

(1) Conifers: They show distinct annual rings.

(2) Deciduous: They do not show distinct annual rings.

Conifers are also known as evergreen trees and leaves of these trees do not fall till new once are grown., as these trees bear cone-shaped fruits, they are named Conifers. These trees yield soft woods .

Deciduous trees are also known as broad leaf trees and leaves of these trees fall in autumn and new once appear in spring. Timber for engineering purposes is mostly derived from deciduous trees. These trees yield hard woods

2. Endogenous Trees: These trees grow inwards and fibrous mass is seen in their longitudinal sections. Timber from these trees has very limited engineering applications Examples of endogenous trees are bamboo, cane, palm, etc.

STRUCTURE OF A TIMBER TREE :-

From the visibility aspect, the structure of a tree can be divided into two categories:

(1) Macrostructure

(2) Microstructure

(1) Macrostructure:

The structure of wood visible to the naked eye or a small magnification is called the microstructure

1. Pith: The innermost central part or the core of the tree is called the pith or medulla

2. Heart Wood: The inner wood rings surrounding the pith is known as heart wood . It is usually dark in color.

It does not take active part in the growth of tree but it imparts rigidity to tree and hence. it provide strong and durable timber for various engineering purposes.

3. Sap Wood: The outer annual rings between the heart wood and cambium layer is known as sap wood . it is usually light in color and weight. It indicates recent growth and it contains sap.

It takes active part in the growth of tree and sap moves in an upward direction through it. Sap wood is also known as alburnum.

4. Cambium Layer: The thin layer of sap between sap wood and inner bark is known as cambium layer. It indicates sap which has not yet been converted into sap wood.

5. Inner Bark: It gives protection of cambium. layer from any injury.

6. Outer Bark: It Consists of cells of wood fibers and is also known as Cortex

7. Medullary Rays: The thin radial fibers extending from pith to cambium layer are known as medullary rays. The function of these rays is to hold together the annual rings of heart wood and sapwood.

( B ) Microstructure :
The structure of wood apparent only at great magnifications is called the microstructure ,

• Wood consists of living and dead cells of various sizes and shapes .

• A living cell consists of four parts , namely
( i ) membrane ,
(ii) protoplasm
( iii ) sap
( iv ) Core.
Cell membrane consists mainly of cellular tissue and cellulose . Protoplasm is a granular , transparent , VISCOUS , Vegetable protein composed of carbon , hydrogen , oxygen , nitrogen and sulpher. core of cell differs from protoplasm mainly by the presence of phosphorus and it is

generally oval .
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WHAT IS CONTOUR AND CHARACTERISTICS OF CONTOUR LINE?

noreply@blogger.com (The civil structure) — Sun, 21 Apr 2019 08:15:00 +0530

WHAT IS CONTOUR AND CHARACTERISTICS OF CONTOUR LINE?

CONTOUR :- A CONTOUR IS AN IMAGINARY LINE ON THE GROUND JOINING THE POINTS OF EQUAL ELEVATION.

IT is the line in which the surface of ground is intersected by a level surface. A contour line is a line on the map representing a contour.

CHARACTERISTICS OF CONTOUR:-

1 . Two contour lines of difference elevations cannot cross each other .

If they did the Point of intersection would have two different elevations which is absurd .

2. Contour lines of different elevations can intersect only in case of an overhanging cliff or a cave.

Overhanging cliff

3 . Contour lines close together indicate steep slope .

They indicate a gentle slope if they are far apart .

If they are equally spaced , uniform slope is indicated .

A series of equally spaced contour lines indicate plane surface.

4 . A contour passing through any point is perpendicular to the line of steepest slope at that point .

5 . One or more closed higher contour line inside , it represents a hill ( Summit).

6. One or more closed lower contour line inside , it indicate a depression ( pond ) .

7. A contour line must close upon itself , though not necessarily within the limits of the map .

8 . Contours deflect uphill at valley lines and downhill at ridge lines.

Contour lines U - shape cross a ridge and in V shape cross a valley at right angles .

The concavity in contour lines is towards higher ground in case of ridge and towards lower ground in case of valley .

9. Contour lines cross a watershed or ridge line at right angles .

They form curves of U-shape round it with the concave side of the curve towards the higher ground .

10 . The same contour appears on either sides of a ridge or valley .

For the highest horizontal plane that intersects the ridge must cut it on both sides.

11 . Contour lines meeting at a point indicate a vertical cliff .

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Levelling important definitions, terms and quizzes.

noreply@blogger.com (The civil structure) — Fri, 19 Apr 2019 22:46:00 +0530

LEVELLING :- very important definition and terms.

👇 For surveying quiz go down 👇 👇

LEVELLING :-

Levelling is a branch of surveying the object of which is :

( 1 ) to find the elevations of given points With respect to a given or assumed datum , and
( 2 ) to establish Points at a given elevation or at different elevations with respect to a given or assumed datum .

Levelling deals with measurements in a vertical plane .

1. Level Surface :-  A level surface is defined as a curved surface which at each point is perpendicular to the direction of gravity at the point . The surface of a still water is a truly level surface . Any surface parallel to the mean spheroidal surface of the earth is , therefore , a level surface .

2. Level Line .:- A level line is a line lying in a level surface . It is , therefore , normal to the plumb line at all points .

3. Horizontal Plane:- Horizontal plane through a point is a plane tangential to the level Surface at that point . It is , therefore , perpendicular to the plumb line through the point .

4. Horizontal Line:- . It is straight line tangential to the level line at a Point . It is also perpendicular to the PLUMBE line .

5. Vertical Line :- It is a line normal to the level line at a point .it is commonly considered to be the line defined by a plumb line .

6. Datum ,:-  Datum is any surface to which elevations are referred . The mean Sea level affords a convenient datum / world over , and elevations are commonly given as So much above or below sea level . It is often more convenient , however , to assume some other datum , specially if only the relative elevations of points are required .

7. Elevation :-  The elevation of a point on or near the surface of the earth is its vertical distance above or below an arbitrarily assumed level surface or datum . The difference in elevation between two points is the vertical distance between the two level surfaces in which the two points lie .

8. Vertical Angle:-   . Vertical angle is an angle between two intersecting lines in a vertical plane . Generally , one of these lines is horizontal .

9. Mean Sea Level :-. Mean sea level is the average height of the sea for all stages of the tides . At any particular place it is derived by averaging the hourly tide heights over a long period of 19 years .

10. Bench Mark .:-  Bench Mark is a relatively permanent point of reference whose elevation with respect to some assumed datum is known . It is used either as a starting Point for levelling or as a point upon which to close as a check .

11. Station :- In levelling , a station is that point where the level rod is held and not Where level is set up. It is the point whose elevation is to be ascertained or the point that is to be established at a given elevation.

12. Height of Instrument ( H . L ) :- For any set up of the level , the height of instrument is the elevation of plane of sight ( line of sight ) with respect to the assumed datum . It does not mean the height of the telescope above the ground where the level stands .

13. back Sight ( B . S . ) :-  . Back sight is the sight taken on a rod held at a point that of known elevation , to ascertain the amount by which the line of sight is above point and thus to obtain the height of the instrument . Back sighting is equivalent to measuring up from the point of known elevation to the line of sight . It is also known as a plus Sight
as the back sight reading is always added to the level of the datum to get the height of the instrument .
The object of back sighting is , therefore , to ascertain the height of the plane of sight .

14. Fore Sight ( F . S . ) .:-  Fore sight is a sight taken on a rod held at a point of unknown elevation , to ascertain the amount by which the point is below the line of Sight and thus to obtain the elevation of the station . Fore sighting is equivalent to measuring down from the line of sight .
It is also known as a minus sight as the fore sight reading is always subtracted ( except in special cases of tunnel survey ) from the height of the instrument to get the elevation of the point .
The object of fore sighting is , therthere, to ascertain the elevation of the point.

15. Turning Point ( T . P . ) :-. Turning point or change point is a point on which both minus sight and plus sight are taken on a line of direct levels. The minus Sight ( fore Sight ) is taken on the point in one set of instrument to ascertain the elevation of the point while the plus Sight ( back sight ) is taken on the same point in other set of the instrument to establish the new height of the instrument .

16. Intermediate Station ( I . S . ) .:-  Intermediate station is a point , intermediate between two turning points , on which only one sight ( minus sight ) is taken to determine the elevation of the station.
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NOW ITS SURVEYING QUIZ TIME...

Surveying quiz and article about theodolite and its important terms

noreply@blogger.com (The civil structure) — Thu, 18 Apr 2019 21:20:00 +0530

THEODOLITE AND ITS IMPORTANT TERMS :- -

(for SURVEYING QUIZ.,go down)

THEODOLITE :-

The Theodolite is the most precise instrument designed for the measurement of horizontal , vertical angles and has wide applicability in surveying such as laying of horizontal angles, locating points on line, prolonging survey lines, establishing grades, determining difference in elevation, setting out curves etc.

Theodolites may be classified as:-

(1) Transit theodolite.

(2) Non-transit theodolite

A transit theodolite (or simply 'transit) is one is which the line of sight can be reversed by revolving the telescope through 180° in the vertical plane. The non-transit theodolite either plain theodolite or Y-theodolite in which the telescope cannot be transited. The transit is mainly used and non-transit theodolite have now become obsolete.

ITS COMPONENTS PARTS....

How Does a Theodolite Work?

A theodolite works by combining optical plummets (or plumb bobs), a spirit (bubble level), and graduated circles to find vertical and horizontal angles in surveying. An optical plummet ensures the theodolite is placed as close to exactly vertical above the survey point. The internal spirit level makes sure the device is level to to the horizon. The graduated circles, one vertical and one horizontal, allow the user to actually survey for angles.

DEFINITIONS AND TERMS : -

(1) The vertical axis:- The vertical axis is the axis about which instrument can be rotated in a horizontal plane. This is the axis about which the lower and upper plates rotate.

2) The horizontal axis. :-

The horizontal or trunnion axis is the axis which the telescope and the vertical circle rotate in vertical plane.

(3) The line of sight or line of collimation.:-

It is the line passing through intersection of the horizontal and vertical cross-hairs and the optical center of the object glass and its continuation.

(4) the axis of level tube:-

The axis of the level tube or the bubble line is a straight line tangential to the rectangular curve of the level tube at its center. The axis of the level-tube is horizontal when the bubble is central .

(5) Centring :-

The process of setting the theodolite is exactly over the station mark is known as centering.

(6) Transiting.:-

It is the process of turning the telescope in vertical plane through 180 ° about the trunnion axis. Since the line of sight is reversed in this operation, it is also known as plunging or reversing .

(7) Swinging the telescope :-

It is the process of turning the telescope in horizontal plane. If the telescope is rotated in clock-wise direction, it is known as right swing. If telescope is rotated in the anti-clockwise direction, it is known as the left swing.

(8) Face left observation.:-

If the vertical circle is the left of the observer, the observation of the angle (horizontal or vertical) is called face left observation.

(9) Face right observation:-

If the face of the vertical circle is the right of the observer The vertical circle is to the observer the observation is know as face right observation.

(10) Telescope normal:-

A telescope is said to be normal or direct when the face of the vertical circle is to the left and "the bobble ( of the telescope) up " .

(11) Telescope inverted.:-

A telescope is said to inverted or reversed when the vertical circle is to the right and" bobble down ".

(12) Changing face.:-

It is an operation of bringing the face of the telescope from left to right and Vise versa.

Advantages of Using a Theodolite:-

Theodolites have many advantages when compared to other leveling instruments:

Greater accuracy.
Internal magnifying optical system.
Electronic readings.
Horizontal circles can be instantly zeroed or set to any other value.
Horizontal circle readings can be taken either to the left or right of zero.
Repeat readings are unnecessary.

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ANALYSIS OF STRESS AND MOHR'S CIRCLE IMPORTANT TERMS AND DEFINITIONS.

noreply@blogger.com (The civil structure) — Thu, 18 Apr 2019 09:08:00 +0530

ANALYSIS OF STRESS AND MOHR'S CIRCLE

IMPORTANT TERMS AND DEFINITIONS.:-

1. Body Force : A force acting distributed over the volume of body is termed as a body forces.

BODY FORCE = Force/Volume OR Unit mass

2. Surface Force : A force which acts distributed over the surface area is called a surface force.

Surface force = Force/ Surface Area

3. Principal plane : The plane on which only normal stresses acts and no shear stress is called as principal plane.

Plane AB, BC, CD and AD as shown in figure carries only normal stress and no shear stress. These planes are called as principal planes.

4. Principal stress : The magnitude of normal stress acting on the principal plane is called as principal stress.

5. Major principal stress:

It is maximum value of normal stress acting on the principal plane.
It is the maximum intensity of direct stress.

6.Minor principal stress :

It is the minimum value of normal stress acting on the principal plane.
It the minimum intensity of direct stress.

7. Major principal plane : plane which carries the major principal stress is called as major principal plane

8. Minor principal plane : plane which carries the minor principal stress is called as minor principal plane

9. Resultant stress : The resultant of the normal stress and the tangential stress is called as resultant stress.

It is denoted by "σ.r"

where ,σ.n = Normal stress,
て = Tangential stress

10. Angle of obliquity : The angle made by the resultant stress with the normal stress is called as angle of obliquity. It is denoted by "Φ" .
TanΦ = て/σ.n

11. Stresses on a oblique section of a body: Following are various cases, for determination of stresses on an oblique section of body:

A member subjected to axial stress.
A member subjected to normal stresses in two mutually perpendicular directions.
A member subjected to shear stress.
Member subjected to normal stresses in two mutually perpendicular direction accompanied by a simple shear stress.

MOHR'S CIRCLE METHOD OF STRESS ANALYSIS.

A graphical method of finding principal stresses, normal, tangential and RESULTANT stress with the help of circle is called Mohr's circle method .

In this method, direct stress 'σ' is represent on x-axis and shear stress 'て' on y-axis .
Tensile direct stress is taken on x-axis and compressive direct stress on negative x-axis.
Shear stress produced clockwise moment in the element is considered positive and anticlockwise moment is negative.
Centre of circle is found by,
where o, and o, are direct stresses.
Radius of circle,
In Mohr's circle , the angle between the planes will be represented by double the angle.
For eg. when circle drawn from centre C with radius R, it cuts x-axis at points and B where shear stress is zero. The angle between AOB-180 but angle between two principal planes is 90.
At point A and B, since there is no shear stress, OA and OB represents principal stresses.
Radius of circle mohr's circle indicates the maximum shear stress, which is located at 2 0 with respect to x-axis, i.e. at 2x45=90 .

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SIMPLY SUPPORTED BEAM

noreply@blogger.com (The civil structure) — Thu, 18 Apr 2019 09:02:00 +0530

SIMPLY SUPPORTED BEAM :-

A simply supported beam is a type of beam that has pinned supported one end and roller support at the other end. Depending on the load applied, it undergoes shearing and bending. It is the one of the simplest structural elements in existence.

(UDL AND POINT LOAD CONDITIONS)

Stress in a bending beam can be expressed as :-

σ = y M / I

where
σ = stress (Pa (N/m2), N/mm2, psi)
y = distance to point from neutral axis (m, mm, in)
M = bending moment (Nm, lb in)
I = moment of Inertia (m4, mm4, in4)

Beam Supported at Both Ends - Uniform continuous Distributed Load

Maximum moment in a beam with uniform load supported at both ends:

Mmax = W L2 / 8

where
Mmax = maximum moment (Nm, lb in)
q = uniform load per length unit of beam (N/m, N/mm, lb/in)
L = length of beam (m, mm, in)

Moment in position x:

Mx = qx (L - x) / 2

where
Mx = moment in position x (Nm, lb in)
x = distance from end (m, mm, in)

Maximum Stress

Maximum stress in a beam with uniform load supported at both ends:

σmax = ymax q L2 / (8 I)

where
σmax= maximum stress (Pa (N/m2), N/mm2, psi)
ymax = distance to extreme point from neutral axis (m, mm, in)
1 N/m2 = 1x10-6 N/mm2 = 1 Pa = 1.4504x10-4 psi
1 psi (lb/in2) = 144 psf (lbf/ft2) = 6,894.8 Pa (N/m2) = 6.895x10-3 N/mm2

Maximum deflection:

y_M = - (5/384) [q.L³/EI]

where
Ym = maximum deflection (m, mm, in)
E = Modulus of Elasticity (Pa (N/m2), N/mm2, psi)

Note! - deflection is often the limit factor in beam design. For some applications
beams must be stronger than required by maximum loads, to avoid unacceptable deflections.

Forces acting on the ends:

R1 = R2
= q L / 2

where
R = reaction force (N, lb)

Maximum slop :-

θ = θ_A = -W.L²/24EI

Example - Beam with Uniform Load :-
The maximum stress in a "W 12 x 35" Steel Wide Flange beam, 100 inches long, moment of inertia 285 in4, modulus of elasticity 29000000 psi, with uniform load 100 lb/in can be calculated as

σmax = ymax q L2 / (8 I)

= (6.25 in) (100 lb/in) (100 in)2 / (8 (285 in4))
= 2741 (lb/in2, psi)

The maximum deflection can be calculated as
δmax = 5 q L4 / (E I 384)

= 5 (100 lb/in) (100 in)4 / ((29000000 lb/in2) (285 in4) 384 = 0.016 in

Beam Supported at Both Ends - Load at Center

Maximum moment in a beam with centercload supported at both ends:

Mmax = F L / 4

Maximum Stress

Maximum stress in a beam with single center load supported at both ends:

σmax = ymax F L / (4 I)

where

F = load (N, lb)

Maximum deflection can be expressed as

δmax = F L3 / (48 E I)

Forces acting on the ends:

R1 = R2

= F / 2

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How to beam fail :-

Design of column

noreply@blogger.com (The civil structure) — Sat, 13 Apr 2019 09:32:00 +0530

Design of Column

Column design

Working Stress Method<

Slenderness ratio (λ)

If λ > 12 then the column is long.

Load carrying capacity for short column

where, A_C = Area of concrete,

σ_SC Stress in compression steel

σ_CC Stress in concrete

A_g Total gross cross-sectional area

A_SC Area of compression steel

Load carrying capacity for long column

where,

C_r = Reduction factor

where, l_eff = Effective length of column

B = Least lateral dimension

i_min = Least radius of gyration and

where, l = Moment of inertia and A = Cross-sectional area

Effective length of column

Effective length of Compression Members

Column with helical reinforcement

Strength of the column is increased by 5%

for short column

for long column

Longitudinal reinforcement

(a) Minimum area of steel = 0.8% of the gross area of column

(b) Maximum area of steel

(i) When bars are not lapped A_max = 6% of the gross area of column

(ii) When bars are lapped A_max = 4% of the gross area of column

Minimum number of bars for reinforcement

For rectangular column 4

For circular column 6

Minimum diameter of bar = 12 mm

Maximum distance between longitudinal bar = 300 mm

Pedestal: It is a short length whose effective length is not more than 3 times of lest lateral dimension.

Transverse reinforcement (Ties)

where dia of main logitudnal bar

φ = dia of bar for transverse reinforcement

Pitch (p)

where, φ_min = minimum dia of main longitudinal bar

Helical reinforcement

(i) Diameters of helical reinforcement is selected such that

(ii) Pitch of helical reinforcement: (p)

where,

d_C = Core diameter = d_g – 2 × clear cover to helical reinforcement

A_G = Gross area

d_g = Gross diameter

V_h = Volume of helical reinforcement in unit length of column

φ_h = Diameter of steel bar forming the helix

d_h = centre to centre dia of helix

= d_g – 2 clear cover - φ_h

φ_h = diameter of the steel bar forming the helix

Some others IS recommendations

(a) Slenderness limit

Unsupported length between end restrains 60 times least lateral dimension.
If in any given plane one end of column is unrestrained than its unsupported lengthAll column should be designed for a minimum eccentricity of

Limit state method

Slenderness ratio (λ)
if
λ<12 Short column

Eccentricity

If then it is a short axially loaded column.
where, P_u = axial load on the column
Short axially loaded column with helical reinforcement
Some others IS code Recommendations

(a) Slenderness limit

(i) Unsupported length between end restrains 60 times least lateral dimension.

(ii) If in any given plane one end of column is unrestrained than its unsupported length

(b) All column should be designed for a minimum eccentricity of

Concentrically Loaded Columns

Where e = 0, i.e., the column is truly axially loaded.

This formula is also used for member subjected to combined axial load and bi- axial bending and also used when e > 0.05 D.

*****

The civil structure

Difference between Prismatic Compass and Surveyor Compass

Difference between Prismatic Compass and Surveyor Compass

Sludge disposal amd management

Sludge disposal: -

Concrete vibrators

Deep foundation

DEEP FOUNDATIONS :-

Sand replacement method

SAND REPLACEMENT METHOD :-

RAFT FOUNDATION

RAFT FOUNDATION :-

Raft foundation may be used under thefollowing conditions:

Methods of Plane Table Surveying

Definition of Pressure, density, specific weight, and gravity

Pressure (P):

Density ( ρ):

• Relative density or specific gravity which is defined as :-

Specific Weight ( w):-

Specific Gravity or Relative Density(s):-

Plane Table Surveying and its advantages and disadvantages

Limit State Method

Working Stress Method

TURBULENT FLOW AND LAMINAR FLOW

SYMON'S NON RECORDING RAIN GAUGE

ROAD ROLLER and their types

ROAD ROLLER and their typs

(4) sheep foot roller

Building material quiz and article about structure of a timber tree.

STRUCTURE OF A TIMBER TREE:-

For building material quiz - go down

STRUCTURE OF A TIMBER TREE :-

WHAT IS CONTOUR AND CHARACTERISTICS OF CONTOUR LINE?

WHAT IS CONTOUR AND CHARACTERISTICS OF CONTOUR LINE?

CHARACTERISTICS OF CONTOUR:-

Levelling important definitions, terms and quizzes.

LEVELLING :- very important definition and terms.

👇 For surveying quiz go down 👇 👇

LEVELLING :-

Levelling is a branch of surveying the object of which is :

NOW ITS SURVEYING QUIZ TIME...

Surveying quiz and article about theodolite and its important terms

THEODOLITE :-

How Does a Theodolite Work?

DEFINITIONS AND TERMS : -

(11) Telescope inverted.:-

(12) Changing face.:-

Advantages of Using a Theodolite:-

ANALYSIS OF STRESS AND MOHR'S CIRCLE IMPORTANT TERMS AND DEFINITIONS.

ANALYSIS OF STRESS AND MOHR'S CIRCLE

IMPORTANT TERMS AND DEFINITIONS.:-

MOHR'S CIRCLE METHOD OF STRESS ANALYSIS.

SIMPLY SUPPORTED BEAM

SIMPLY SUPPORTED BEAM :-

A simply supported beam is a type of beam that has pinned supported one end and roller support at the other end. Depending on the load applied, it undergoes shearing and bending. It is the one of the simplest structural elements in existence.

(UDL AND POINT LOAD CONDITIONS)

Stress in a bending beam can be expressed as :-

σ = y M / I

Beam Supported at Both Ends - Uniform continuous Distributed Load

Maximum deflection:

Maximum slop :-

Beam Supported at Both Ends - Load at Center

Maximum moment in a beam with centercload supported at both ends:

Mmax = F L / 4

How to beam fail :-

Design of column

Design of Column

Column design

Working Stress Method<

Limit state method

Raft foundation may be used under the
following conditions: