Important things in civil engineering

Raft foundation being casted

Fixing of stirrups done here is wrong care should be taken to bend the end of stirrups at included angle of 45 degree as per IS code 456

Cutting of soil should be done in steps and in a definite slope

Support system being provided in case of casting of vertical concrete members

Type of formwork being used in case of semi-circular or circular casting of concrete members

Date should be mentioned on concrete members in order to avoid error regarding curing....

Pdestal

Stirrups

Stepwise procedure for executing a project in GIS

Step 1: Identify your objectives:
The first step of the process is to identify the objective of
the analysis. You should consider the following questions
when you are identifying your objectives:

. What is the problem to solve? How is it solved now?
Are there alternate ways to solve it using a GIS?
. What are the final products of the project.reports,
working maps, presentation-quality maps?
. Who is the intended audience of these products.the
public, technicians, planners, officials?
. Will the data be used for other purposes? What are the
requirements for these?
This step is important because the answers to these
questions determine the scope of the project as well as how
you implement the analysis.

Step 2: Create a project database
The second step is to create a project database. Creating the
project database is a three-step process. The steps are
designing the database, automating and gathering data for
the database, and managing the database.
Designing the database includes identifying the spatial data
you will need based on the requirements of the analysis,
determining the required feature attributes, setting the
study area boundary, and choosing the coordinate system to
use.
Automating the data involves digitizing or converting data
from other systems and formats into a usable format as well
as verifying the data and correcting errors.
Managing the database involves verifying coordinate
systems and joining adjacent layers.
Creating the project database is a critical and timeconsuming
part of the project. The completeness and
accuracy of the data you use in your analysis determines
the accuracy of the results.

Step 3: Analyze the data
The third step is to analyze the data. As you.ve seen,
analyzing data in a GIS ranges from simple mapping to
creating complex spatial models. A model is a
representation of reality used to simulate a process, predict
an outcome, or analyze a problem.
A spatial model involves applying one or more of three
categories of GIS function to some spatial data. These
functions are:
. Geometric modeling functions.calculating distances,
generating buffers, and calculating areas and perimeters.
. Coincidence modeling functions.overlaying datasets to
find places where values coincide.
. Adjacency modeling functions.allocating, pathfinding,
and redistricting.
With a GIS you can quickly perform analyses that would be
impossible or extremely time consuming if done by hand.
You create alternative scenarios by changing your methods
or parameters and running the analysis again.

Step 4: Present the results
The fourth step is to present the results of your analysis.
Your final product should effectively communicate your
findings to your audience. In most cases, the results of a
GIS analysis can best be shown on a map.
Charts and reports of selected data are two other ways of
presenting your results. You can print charts and reports
separately, embed them in documents created by other
applications, or place them on your map.

Types of analysis in GIS

Different types of analysis that can be done:

There are two types of GIS queries,
attribute and location queries.
Attribute queries, also called aspatial queries, find features
based on their attributes
Location queries, also called spatial queries, find features
based on where they are.

A third type of GIS analysis is finding what is near a
feature. One way to find what is near a feature is by
creating a buffer around the feature.

A fourth type of GIS analysis is overlaying different layers
of features.

There are several different spatial overlay and spatial
manipulation operations that you can use on layers
including union, intersect, merge, dissolve, and clip.

Steps for the project in GIS

Steps for a project:

The first step is to convert a question.

The next step is to create a database that contains the
geographic data required to answer the question. This may
involve digitizing existing maps, obtaining and translating
electronic data from a variety of sources and formats, making sure the layers are of adequate quality for the task,
making sure the layers are in the same coordinate system
and will overlay correctly, and adding items to the data to
track analysis result values.

The next step is to analyze the data. This usually involves
overlaying different layers, querying attributes and feature
locations to answer each logical part of the question,
storing the answers to the logical parts of the question, and
retrieving and combining those answers to provide a
complete answer to the question.

The final step in a project-based analysis is to
communicate the results of the analysis, usually to people
who do not use GIS and who have different levels of
experience in dealing with maps. Maps, reports, and graphs
are all used, often together, to communicate the answer to
the question.

Applications of gis in various fields

Various applications:

1.An engineering department
monitors the condition of roads
and bridges and produces
planning maps for natural
disasters.
2.A water department finds the
valves to isolate a ruptured water
main.
3.A transit department produces
maps of bicycle paths for
commuters.
4.A wastewater department
prioritizes areas for repairs after
an earthquake.
5.A hydrologist monitors water
quality to protect public health.
6.A biologist studies the impact of
construction plans on a
watershed.
7.A pipeline company finds the
least-cost path for a new
pipeline.
8.A meteorologist issues warnings
for counties in the path of a
severe storm.
9.A businessman evaluates locations
for new retail outlets by
considering nearby
concentrations of customers.
10.An emergency management
agency plans relief facilities by
modeling demand and
accessibility
11.A fire fighting team predicts the
spread of a forest fire using
terrain and weather data.
12.A water resource manager traces
upstream to find the possible
sources of a contaminant.

Coupler system

Couplers being fitted on the threaded portion (one end of the bar)

Coupler system-mechanical splicing method to prevent lapping(generally being provided in the site). This system provides more strength as well as prevent wastage of steel.(for detail please visit post named coupler system)

civil engineering machinery

Machine for smoothening the ribs(lugs/protrussions) longitudinal as well as transverse. For threading purpose.

Bar Cutting Machine

Bar Cutting Machine-different dia of bars can be cut by this machine upto 40 mm diameter

Concrete mixer

Bar Bending

How Bar Bending is being done in the site:

Honey combing

Defect in concrete due to honey combing and improper formwork

Honey combing one of the defects in concreting process which causes loss of strength in the structure and is being caused due to insufficient vibration.

Honey combing being corrected by the process of grouting.(mixture of cement and sand of appropriate strength is being injected into the honey combs after proper cleaning,chirping and applying necessary chemicals to it)

Surveying

Dumpy level and JCB in the site. JCB doing the levelling work. JCB can be used for various purposes in the site like-cutting,filling,transportation, as a supporting equipment(when concrete mixers(with rubber tyres) in the site get punctured it can give support).

Sort of benchmark (reference level).For surveying in the site or transfer of height of one object to another.

Dumpy level - instrument for checking the level in the site.For marking purposein the site generally chalk powder(lime powder) is being used as in the photo.

Transit mixer

Concrete mixer-hauling equipment. Used for transportation of concreting from batching plant to the site. These are of varying capacities ranging from 6 cubic metre to 8 cubic metre.One shown here is of 7.5 cubic metre capacity.

Transit mixer pouring its concrete in the pump for transportation of concrete to the desired place, further transportation of concrete is being done through pipe. For pumpable concrete slump should be in between 80mm to 120mm.

construction joint

Construction joint being provided in the raft foundation. it acts as the key of bondage in between the old and new concreting.

Cover block

Cover block kept in the pan. These cover blocks should have wire attatched or embedded in them in order to fix them nicely in bars for providing necessary cover.For providing cover of some distance only one cover block should be used at a time. These cover blocks should be of the same quality or grade being used in concreting process

Cover blocks should be tied to the reinforcement bars with the help of the wire embedded in it and coming out slightly(provided for tying purpose) firmly in order to provide necessary cover in the concrete members and maintain required distance in between the formwork and bars.

curing photos

curing being done for the vertical concrete members

METHOD OF DESIGN MIX

Parameters:

1. Characteristic strength of concrete ( grade of concrete )
2. Degree of quality control expected to be exercised at construction site
3. Type and max. size of aggregate
4. Degree of workability desired (slump or compaction factor )
5. Type of Exposure -mild, moderate, etc.
6. Standard deviation of compressive strength of concrete.

Test Data on materials required :

1. Sp. gravity of cement
2. Test data on cement - testing ( 28 days comp. strength if available )
3. Sp. gravity and water absorption of coarse and fine aggregate
4. Grading of coarse and fine aggregates

Steps of mix design :

1. Ascertain characteristic strength.
2. Select workability of concrete . ex-for pumpable slump required is 100 mm(80-120)or for manual 25 to 40 mm.
3. From the known degree of control and the required characteristic strength, determine the standard deviation(SD) (clause 9.2.4.2-IS 456) from table -8 IS-456.
4. Fix the target strength from the equation : Target strength=fck + 1.65*SD
5. Choose the brand of cement
6. Collect the curve of w/c ratio VS target mean strength from cement manufacturer
7. Determine free w/c ratio (from curve of cement manufacturer)
8. Determine Maximum free w/c ratio(IS-456 table -5) . If maximum w/c ratio is greater than w/c ratio chosen from curve then take value(from curve) as ok otherwise take maximum value as per code(lower of the two values).
9. Select and adjust water content - "maximum water content (table -6 of IS -10262) in accordance to use of super plasticizer or any admixture"
10. Select type and maximum size of aggregate
11. Select and adjust fine aggregate percentage -take 33% as per general thumb rule (i.e., fine aggregate-sp 23 table 36 and table 6 of IS -10262)
12. Calculate cement content-having known the quantity of water we go back to step -8 and taking that water-cement ratio , determine the weight of cement from the equation cement in kg=(water in kg /water –cement ratio ).

On going through the above steps , we have obtained the following values :

Cement in kg per Cu m of concrete
Water in kg per Cu m of concrete
The percentage of sand (fine aggregate) in the total aggregate.

13.Check minimum cement content (IS -456 table 5 ) and compare it with that obtained above and apply correction if required, adopt the greater of the two values .

14.Estimation of entrapped air (if required) .This correction is for the entrapped air in concrete. The percentage of entrapped air depends upon the degree of compaction. Even after good compaction, there will be some entrapped air in concrete. (IS – 10262 table -3).

15.Calculate aggregate content: the sand and coarse aggregate content are calculated by absolute volume method using the following equations :-

Equation 1 - V= [W+(c/Sc) + (1/p)*(fa/Sfa)]*(1/1000)

Equation 2- V= [W+(c/Sc) + (1/(1-p))*(Ca/Sca)]*(1/1000)

Where ,

V=absolute volume of fresh concrete, which is equal to gross volume in m3 minus the volume of entrapped air,(being 1% for 40 mm max size of agg, 2% for 20 mm max size of agg and 3 % for 10 mm max size of agg)

W=mass of water kg per m3 of concrete

C=mass of cement kg per m3 of concrete

Sc =specific gravity of cement .

p=ratio of fine aggregate to total aggregate by absolute volume,

fa ,Ca =total masses of sand and coarse aggregate, kg per m3 of concrete respectively

Sfa,Sca=specific gravities of saturated surface dry sand and coarse aggregate respectively.

16.Corrections are to be made in water and aggregate contents for the moisture . which is already there in the coarse, and fine aggregates as supplied at site . if not known, as first approximation one can assume it from experience . Generally, the coarse aggregates carries 0.5% and sand (Zone II to 2%)(sp 23 table 36 )

17.Select type and dosage of admixture-Calculate admixture content.(as per the dosage prescribed by the manufacturer for the type of cement being used in the site)

18.Blending of coarse aggregates-we have to take different sizes of aggregate in such a ratio so it should fall within the limits as per IS -383 table 2 and 5.

19.Tabulate initial trial mix .

20.Conduct the trial mix and check slump(initial, after ½ hr, after 1 hr) cast 9 nos of cubes for testing compressive strength of concrete- 3 cubes for 3 days , 3 cubes for 7 days , 3 cubes for 28 days.

21.Additional trial varying (water +/- 5% , cement +/- 5 %,admixture +/- 10 %) check slump in each of the six cases.

22.Choose the final concrete mix.

Assumptions : (if not given)

1. Specific gravity of fine(2.6) and coarse(2.67) aggregate .
2. Water absorption of fine(1%) and coarse(0.5%) aggregate.
3. Free surface moisture of fine(2%) and coarse(nil) aggregate.
4. Entrapped air(2%).
5. Degree of quality control(GOOD).