modern construction technology introduction

Designs of man-made structures are more complex than ever before, and they are getting no-
simpler. Requirements are increasing. Human tendency to compare the previous project with the
future one is just one of the reasons. Other reasons for pushing the construction engineering off
limits, include increasing population, use of newly developed materials together with software
developments, which allow us to design these complex structures. The engineering techniques
required for the implementation of designs are highly specific in nature and vary from design to
design. Look alone at the simple construction of pavement designs. Here, the performance of the
pavement is largely dependent on the sub grade and base layers. Durability and stability of the
pavement are decided by the ability of the sub base layers to provide strength and modulus in the
moist and underground conditions.
Since the top most layer is usually the one facing the largest stress and hence coated with
premium materials, the foundation must be uniform and stiff to support them. Engineering
constructions have grown to become highly sophisticated and organized in nature. One of the
prominent reasons is the concern for the safety of human life. In the simple case of pavement
engineering itself, there are various ways to measure the quality of construction. One of them is
Ride Quality parameter which measures the ride quality on the pavement. Non-destructive testing
techniques include Ground Penetrating Radar (GPR) and Falling Weight Deflectometers (FWD).
We prepared and published this seminar abstract for final year engineering students seminar
research. You should do your own research additional to this information before presenting your
seminar.

plinth

1. Prevent leaking of water into foundation -
To prevent a house from settling it is
critical that no water be leaked into
foundation. Being made of cement, plinth
beam is impervious and therefore prevents
water from rain, flooding, etc. from leaking
into foundation.
2. Provides support for walls - For load
bearing houses, walls carry the weight of
the house. Plinth beam provides solid
footing to raise those walls.
3. Holds house together - Since plinth beam
sits across the periphery of the house, it
provides binding force across rooms. For
example, without plinth beam it is
possible for one of the rooms to settle
thus creating uneven floor level. Plinth
beam prevents that from happening.
Basic process to construct plinth beam is as
follows:
1. Mark-up width - Usually width of plinth is
half that of the foundation. In this case,
foundation is about 18" wide and so
plinth is 9" aligning with the outer edge of
the foundation. Inner 9" of foundation
meshes into the floor level of the house.
2. Lay down the steel beam - As the
adjacent picture shows beams are the
core of the plinth beam.  Beams have a
loop every 6" that holds it together.
3. Setup re-inforcement - Before concrete is
poured, re-inforcement has to be
established to provide rectangular shape
to the beam. This takes majority of effort
as planks have to be nailed properly in
place and once concrete is poured they
need to be removed.
4. Pour the concrete - Next step is to pour
the concrete. As concrete is poured,
mason ensures that it is evenly spread
and smoothens out any edges. He also
needs to ensure the height of the beam is
consistent throughout the periphery.
5. Remove re-inforcement - Concrete turns
solid within 24-hour and final step is to
remove the planks leaving the beam
intact.
This short video explains this process in
action.
Foundation Redone:
To give background context, ground level at
living room area is 1' higher than that at the
guest bedroom level. Typical height of plinth
level is 2.5' that includes 1' of plinth beam
and 1.5' of foundation masonry. Turns out
though that foundation masonry was 2.5' at
living room and 3.5' at guest bedroom. What
this meant was plinth height would be 3.5'
from natural ground level. This was realized
only when plinth beam casting was about to
start. To add to misery, by then Rainwater
tank was already done to align with 3.5' of
plinth !
My architect was clear that plinth level can
be no taller than 2.5' or else house would
look place oddly high. What followed was no
fun - We ended-up undoing a few days of
work. Specifically
Reduce Rainwater tank height
by 1' by chipping away at
just-finished concrete tank
Remove 1-layer of foundation
stone masonry from across
the house periphery to reduce
the foundation height by 1'.
Here is the clip of work being undone. It
could have been worse had plinth beam been
built. Good news was we caught it at a time
that cost us about a week and some cost in
material and labor. Having said that, there
were key lessons learnt -
1. Trust your gut instinct - Even though as
homeowners we may not be in
construction business, you have a feel for
what's going on. I certainly did feel that
foundation was looking tall. While "plinth"
was a new term and I didn't know that it
was 1' in height I concluded I knew no
better. That was the critical mistake. No
question is a dumb question especially
when you are new to the domain. Had I
had surfaced my instinct more strongly or
did some research things could have been
different.
2. Working drawing consultation - I
independently found my architect and
contractor. So they had no prior
relationship between them. When architect
released drawings there was no
consultation that occurred between the
two. So, architect didn't get a chance to
explain the nitty-gritty and contractor felt
drawings were clear-enough. A big no-
no ! It is critical that drawings are
released to contractor only after architect
has had a chance to explain them to the
contractor. It is best to have such
meetings at the site to relate paper
drawings to the actual mapping onsite.
Often times, what looks right on paper
doesn't feel right to the eye. If that's not
possible, have them meet at architect's
office.
3. Inspection schedule - Identify stages at
which architect would come and inspect
the site to validate it is built according to
the specifications. In this case, architect
mentioned a couple of times need to
schedule inspection. However, given that
this was first or second inspection we
were not as diligent as needed.
Again, in retrospect, it was not a terrible
setback.. Like many other things in life, none
of the lessons were new; rather they were re-
inforcement of what you would learn at many
other times. Lessons learnt were critical and
have since been put in practice. There is now
tighter collaboration between me or my wife,
architect and the contractor and crisper
conversation about respective point of view.
So, in the end it definitely had a silver lining !

ground beam of building

GROUND BEAMS
Here at Performance Foundations we can provide you with
traditional or piled ground beams for any building project you
may have, such as, an extension, single plot or multiple plots. By
having ground beams installed you can improve construction programmes by reducing poor ground conditions.
Ground Beams are designed to support brick/blockwork or to form a permanent shutter to the edge of insitu
concrete floor slab. The amount of reinforcement introduced into the design will be used to suit specific loading
requirements and the beams can be designed to withstand any heave forces with the use of void forming or
compressible materials.
Installation may require piling, then once that is complete we excavate the ground to a width and depth required
by your design or shuttered above ground. Reinforcement is then placed and the pile reinforcement tied into the
ground beam. After inspection by the relevant authorities the beam will be concreted.
FLOOR STABILISATION
In situations where industrial floors and yards are subject to excessive loading, we can improve the loadbearing
properties of the surface by pile insertion. This is a quick and clean process and causes minimal disruption to
your business.
To support existing concrete ground floor slabs, we can install a permanent pile casing in a pre-bored hole to a
calculated 'set' to carry the working loads. Piles are installed at designed centres and constructed to support the
existing concrete slab by means of an enlarged head at the top of the pile.

steps of foundation of building

Survey and Stake
Before any construction can begin, the home site is surveyed to
establish the home's basic footprint and to ensure the home is set
back the appropriate distances from the property lines. The corners
of the home are marked by surveyor's stakes. Offset stakes, which
are about two feet out from the surveyor's stakes, also are placed.
The excavator will dig at the offset stakes, creating a slightly larger
hole than the foundation actually will occupy. The extra room
enables crews to work on the exterior of the foundation walls.
Excavation
The depth of the excavation is determined by a structural engineer
who considers the soil, the frost line and the height of the water
table (the depth in the soil at which you find water). Surface soil is
removed to expose soil that is compacted enough to bear the load of
the home. The excavation must be deep enough to place the top of
the footing below the frost line. This prevents the concrete from
cracking due to the freeze-thaw cycle of the surrounding soil. The
excavation cannot be so deep that it's below the water table,
however, because that can cause a chronically wet or flooded
basement.
Footings
Footings are poured concrete pathways that help to spread the
weight of the home from the foundation walls to the surrounding
soil. Footings are wider than the foundation walls they support, and
form the perimeter of the home. Sometimes, additional footings are
added inside the perimeter to support load-bearing interior walls.
Sub-slab Systems
Plumbing lines are run from the street to the home's basement, by
going under or over the footing. In some regions, soil gas mitigation
systems are added to collect the soil gases trapped under the slab
and vent them to the outside. Eventually, these systems will be
covered with the poured concrete slab that is the basement floor.
Foundation Drainage Tile System
This system collects subsurface water and moves it away from the
foundation. Foundation drainage tile consists of a continuous run of
perforated drainage pipes embedded in gravel along the outside
perimeter of the footings.
Some building codes require drainage pipes along the inside
perimeter of the footings as well.
Sump
In regions where the earth is flat or the soil tends to be wet, a sump
may be added to help collect subsurface water. A sump pump moves
the collected water away from the home.
Walls
Foundation walls are constructed by pouring concrete between sets
of form work (the total system of support assemblies for freshly
poured concrete, including mold, hardware and necessary bracing.)
Once the concrete gains its full strength, the form work is removed.
Foundation wall thickness is determined by a structural engineer
who considers the height of the wall and the load it has to bear.
(Structural load is the force or combination of forces of gravity,
wind, and earth that acts upon the structural system of a home).
Wall thickness varies from home to home, and even within a home.
Anchor Bolts
Anchor bolts are embedded at pre-determined points along the top
of the foundation walls. They'll be used during framing to secure the
framing to the foundation.
Beam Pockets
Beam pockets are cast in the top of the foundation walls to receive,
support, and hold beams in place.
Dampproofing and Waterproofing
A dampproofing or waterproofing seal is applied to the exterior of
the foundation walls that eventually will be below-ground. This
slows or stops water from traveling through the walls and into the
basement.
Slab
A 3-inch to 4-inch thick concrete slab is poured between the walls.
The slab helps to stabilize the base of the foundation walls, and
also forms the basement floor.
Backfill
Backfill is pushed into the trenches around the exterior of the
foundation walls, burying a portion or all of the walls below the
surface for added stability. Ideally, backfill is soil that drains easily.

soil stabilization

Introduction
Soil stabilization refers to the process of changing soil
properties to improve strength and durability. There are many
techniques for soil stabilization, including compaction,
dewatering and by adding material to the soil. This summary
will focus on mechanical and chemical stabilization based
adding IRC materials. Mechanical stabilization improves soil
properties by mixing other soil materials with the target soil
to change the gradation and therefore change the engineering
properties. Chemical stabilization used the addition of
cementitious or pozzolanic materials to improve the soil
properties. Chemical stabilization has traditionally relied on
Portland cement and lime for chemical stabilization. There a
number of IRC materials that can be used individually, or
mixed with other materials, to achieve soil stabilization.
IRC Materials in Soil Stabilization Applications
Coal fly ash (CFA) has a long history of use in soil stabilization applications. Class F CFA is typically
added to both cement and lime stabilized soils because the pozzolanic reactions provide improved
strength and increased density and durability. In addition, self-cementing (Class C) CFA has been used
successfully to stabilize fined grained soils. It was found that the rapid reactions of the Class C CFA
reduced the plasticity of the soil, lowered the water content and increased the strength of the soil.
Similarly, blast furnace slag in the form of slag cement has also been used successfully for soil
stabilization. Slag cement can be used by itself or mixed with Portland cement, depending on the site
conditions. Slag cement is a cost effective way to dewater the soil and increases the strength. In addition,
work has shown that soil cement can help mitigate sulfate-induced heave than is often encountered
during lime stabilization of sulfate bearing soils.
It should be noted that the performance of CFA and slag cement in soil stabilization applications, like that
of lime and cement, is very dependent on the site conditions. The fines content and plasticity of the soil,
the presence of sulfates, depth to the water table and freeze-thaw conditions are all factors that need to
be considered when stabilizing soil. Test mixture should be made to determine the best mixture for the
site.
Foundry sand has also been shown to be an effective soil stabilization material when added to poor soils
to change the gradation. The foundry sand improves drainage, which leads to better engineering
performance.
Benefits
The use of coal fly ash, slag cement and foundry sand for soil
stabilization provides cost effective methods to improve the
engineering properties of marginal or problematic soils. Soils
stabilized with these materials have been extensively tested
and do not have any adverse environmental impact. In fact,
there is actually an added environmental benefit of reducing
green house gas emissions and energy consumption by using
less energy intensive materials like lime and cement, and by
reducing landfilling of high quality foundry sands.

methods of improving bearing capacity of soil

1. Increasing the depth of the footing is the simplest method of improve the bearing capacity of
soil, This method is restricted to sites where the sub-soil water level is much below and deep
excavations do not increase the cost of foundations disproportionately.
2. Drainage is a well known method to improve the bearing capacity of certain soils . Drains (with
open joints) are laid in trenches just at the footing base. The sub-soil water thus collected is
drained out through a system of pipe drains provided outside the external walls of the building.
3. By blending granular material, like sand, gravel or crushed stone into the natural soil by
ramming. The layer of soil thus formed is much stronger and is of improved bearing capacity.
4. By confining the soil in an enclosed area with the help of sheet piles. This method is used with
advantage in shallow foundations in sandy soils.
5. By driving sand piles. This method is based on the principle of reducing the void volume of the
natural soil. Holes are made in the soft soil with the help of wooden piles or other means and
then sand is filled in the holes and rammed. These are called sand piles. Bearing capacity of soft
soil can be appreciably improved by driving sand piles at close spacing.

affordable housing

The affordable housing segment has emerged
as one of the most vibrant and dynamic
sectors in the Indian real estate industry.
Various factors have contributed to this
growth—on the supply side it is the entry of
various real estate developers and
availability of financial options; whereas
rapid urbanization, growing trend of nuclear
families and rising income levels have fuelled
the demand for affordable housing. There is
hardly a dispute that there still is a
considerable supply shortage in this
segment.
As a concept, affordable housing is not a
new one. It is at least a decade old, with the
local development agencies of big cities
being the original pioneers with their lower
income group flats. While the market for
affordable homes never really diminished,
large real estate firms started focusing
almost exclusively on premium and luxury
projects between 2004 and 2008 as the
economy expanded rapidly and banks and
financial institutions adopted a more liberal
approach to giving out loans.
Since 2008, however, with the overall
changes in the economy and the real estate
market, companies, even large ones, have
turned to low-cost housing projects with a
renewed focus. Large scale real estate firms
have launched low-cost homes at various
locations in the price bracket of Rs.10 lakh
to Rs.30 lakh and investments in the
affordable housing sector are moving north.
A recent news report spotted a rising trend of
homes in the affordable segment being
bought for investment. These were bought by
people who do not plan to stay in them as
the houses are located too far away from
commercial areas and have lesser support
infrastructure. Gujarat, Bangalore, Madhya
Pradesh and Ahmedabad are among the
states that have seen traction in affordable
housing. Given the lower off-take of mid-
range and luxury units in India that are
clearly seeing some challenges, the growth is
going to be sustained from rural and
affordable housing in the range of about
18-20% coupled with the aspirational need
to have a house and by the acute shortage in
this sector.
While less than five years ago there were not
many financiers for customers of affordable
housing, today most big names are entering
rural housing with built-in risk pricing so as
to make it a viable business model. Big
names in the industry are rushing into the
sector to cater to the existing demand
supply gap. More and more projects are
being promoted across India. Tier II and III
cities have seen a higher rate of adoption for
these projects. Low-income customers are
happy with their new homes, improved living
conditions, safe neighbourhoods and
enhanced overall social status, which are
some of the benefits that the segment has
been able to provide. Many banks may be
slow to approach affordable housing
properties because of their remote location
and the estimated land value not meeting
their expectations. In such cases, loans
would be harder to come by and the
perceived higher rates of interest may deter
potential buyers from approaching non-
banking financial companies (NBFCs) that
now focus on retail housing finance business,
a sector dominated by commercial banks.
NBFCs, though, have been able to offer loans
at competitive rates. While banks have been
able to provide loans at relatively cheaper
rates since their cost of funds is lower, debt
markets have come in handy for NBFCs to
raise cheaper funds. Essentially, their focus
on growth segments, efficient loan recovery,
individual focus and simple processes have
helped them keep the cost low and reduce
interest rates on home loans, passing it on
to borrowers.
Indians consider their homes their most
important possession, and, therefore, make
paying their financial obligations towards
them their highest priority. In a challenging
economy, people may think twice before
making any new high-value financial
commitments. They tend to be very cautious
about doing so during times of financial
uncertainty but pursue their home ownership
dreams when they perceive that stability has
been restored in the economy.
The concept of affordable housing as a whole
has been well received by consumers,
developers and financiers; this has led to
end-to-end servicing of this segment, thus
becoming a lucrative proposition for one and
all. Housing finance companies are
expanding to new geographies and
encouraging developer perception of real
demand and ensuring there is enough
awareness and education being imparted to
prospective customers on the home
ownership process through standardization
of processes and campaigns. It helped that
in December, the Reserve Bank of India
allowed real estate developers and housing
finance companies to raise up to $1 billion
through external commercial borrowings to
promote affordable housing projects. This
will help them access cheap overseas funds
and reduce the overall costs. Affordable
housing is the “sunshine” sector for the next
five years from a developer and lender
perspective. To put it simply, this will be the
growth engine of the future for all
stakeholders.