05 Latur Reconst & Technology Options

8/13/2019 05 Latur Reconst & Technology Options

1/9

Impact Of Inappropriate Housing Technology 1

Housing Technology & Its Impact :Latur Earthquake Rehabilitation

Maharashtra State, India

A Case Study

Prepared By

Rajendra Desai & Rupal DesaiNCPDP, 204 Santoor Apartment, Near Parimal Crossing, C.G. Road

Ahmedabad 380009INDIA

Tel: 91 79 550 7841Fax: 91 79 550 7842

e-mail [email protected]

For

Workshop on Low Cost Housing and CommunityParticipation in Construction

At Cebu City, Philippines.

Organized By

A.C.H.R.

October 5, 1997.


2/9


Housing Technology & Its Impact :Latur Earthquake Rehabilitation, A Case Study

Background

Today for a literateIndian, almost anywhere in the country, baring a rare exception, if

the word house reminds him or her of cement, steel and bricks then that would be onlynatural. This is so since, more than likely, that person belongs to an urban area of thecountry. There for the past few decades now, an overwhelming majority of buildings,houses and other, are getting built out of these materials. It does not matter if it is asingle story house or a skyscraper. It does not matter if it is in Srinagar in North orTrivendrum in South. The common denominator is a construction technology based oncement, steel and possibly bricks.

In the same urban area there are the poor, living in the slums, who build just like theircounterparts in the villages out of any thing that they can lay their hands on in thesurrounding environment. It is the urban waste such as wooden crates, metal drums, tin

sheets, cardboard boxes, plastic sheets, woven polypropylene sacks etc. That theysalvage since that is what their resources permit. But they all aspire to build usingcement and bricks, and, if possible, steel. This has little to do with the availability ofthese materials in urban areas.

On the other hand the housing scene is markedly different in the rural locales of thecountry. Most house owners, barring a few very rich, and that too those who have comeunder much external influence, will think of what is naturally found in the surroundingenvironment such as stone, mud, timber, bamboo, leaves, grasses and bricks (which isnothing but transformed mud). This is a natural reflex since traditions, including that ofhouse building, have been little disturbed in these areas of the country, even as the

20th century is coming to a close. This does not imply that the people do not aspire tobuild using cement and steel. The information flow through improved communicationhas also begun to affect their aspirations. But the resource limitation leaves most themlittle choice.

In fact, most every one does aspire for cement and steel mainly because they areconsidered as the most visible signs of modernity and prosperity. Also wrongly or rightlythese materials are seen as sign of permanence.

Vernacular Building Technology

The Vernacular building technology is essentially the technology that has evolved in aparticular area over hundreds of years. In rural areas of our country and of otherdeveloping countries the house building technologies that one sees are the vernaculartechnologies. They have nothing to do with engineers and architects, and the modernsciences. But generations of wisdom and experience have gone in to them. Theyconform to the environment of their respective areas and, hence, depend entirely uponthe resources available in each locale. They provide the most optimum solution towardsmeeting the building needs of a given area. Using todays clich, these technologiesare Eco friendly since virtually all the materials used can be and are routinely recycled.The production of these materials cause, if at all, limited local environmental damage


3/9


that can be repaired. Lastly, vernacular building technology is very much interwovenwith the local culture.

India with its diversity provides a wide variety of vernacular technologies. To name afew, these range from round Bunga (round mud house) of Kutchh region made of mudand scraggly Babul (Acacia) wood, to stone houses with stone slab roofs of aridJodhpur in Rajasthan State, to elegant mud and thatch houses of Santhals in Orissa

State, to earth quake and wind resisting bamboo houses in Arunachal Pradesh in NEIndia etc.

Cost Factor

The greatest advantage of the vernacular building technology is that it is within an easyreach of the masses and tends to remain within their easy reach over a long period oftime. The cost of cement and steel based technologies rises faster than the vernacularones since they are energy intensive. Energy is a scarce resource in our country. Itscost rises faster than the household income of an average Indian family. So a largenumber of households which can afford the cement/steel based technology today verylikely will not be able to some time from now.

On the other hand the cost of traditional materials and skills do not go up any wherenearly as fast as those of energy, transportation and special skilled labour. The localmaterials entail little transportation cost if any. Often, the technologies are simpleenough to utilise the self-labour of the house owners. The costs of local technologiesare generally related to the cost of labour since the material preparation predominantlyuses human power. The local transportation involves little use of fossil fuel such aspetrol or diesel. Hence, from a long-term perspective the local technologies tend toremain within ones reach over a relatively longer period of time than those based on

cement and steel. Propagation of these technologies would certainly help improve thehousing scene.

The houses made of the vernacular technologies do require more frequentmaintenance than those of cement, bricks and steel. But the maintenance is easy andwithin the reach of the masses since it requires neither material nor skill which is notfound locally. And it is cheap, and more so if one is putting in ones own labour.

Sustainability

The vernacular construction technologies are significantly more sustainable than the

cement and steel based technologies because they....

make significant use of renewable resources, use materials that pollute little in their procurement and/or preparation, permit recycling of almost all the materials, do not lead to large scale exploitation of natural resources due their decentralised

mode of application.

Hence, use of these technologies would ensure housing for the most number ofpeople for a long time to come.


4/9


Vernacular Marathawada Construction Technology

Marathawada is no exception when it comes to vernacular construction. With basaltstone being most easily available the stone masonry has been the preferred medium ofwall construction. One finds most exquisite examples of stone construction in thevillages. The roofs consist of a thick layer of soil laid on a timber platform. Timber isobtained from the locally found neem and babul (acacia) trees.

MarathwadasettlementTraditional andstone mudtimber houses.

Interior view of

an introvertedtraditional house.

All necessary skills such of stone quarrying and shaping, carpentry and soil preparationare easily available locally. With the exception of the door and window hinges andlatches, and little cement used for sealing the open joints in the masonry, all materialsare locally found. As a result it is easy and affordable to maintain or repair the houses.

Since the wall and roof, both, are thick, they insulate the interior very well, thus keepingit cool on a hot summer afternoon and warm on a cold winter night. Windows are tiny, ifat all, to keep the heat out. Generally in every room a small 6X6 opening is providedin the roof for ventilation and diffused lighting.


5/9


The rainwater drains off the soil-covered roof since the soil layer is impervious. It isnecessary to remove the weeds a couple of times every year to prevent water fromseeping down. Any leak is tackled by simply placing a few inches of impervious soil.

The stone walls are finished with mud plaster, at times followed by lime wash. Annualmaintenance of these walls is very easy and entails little or no cost. In cooking area thewalls are devoid of lime wash. Hence, the soot-covered walls are frequently finished in

mud and cattle dung slurry to give a new appearance all the time.

Mud timberroof tilted bythe quake.

Earthquake RehabilitationProgramme Houses

The vernacular Latur houses weremade to face heat, cold, rain robbersand invaders, but not earthquake. As a

result they succumbed to just amoderate earthquake.

What is now required is to bring infeatures that would simply improve theseismic strength in these houses so thatthey can continue taking care of allother needs of the people whileremaining within their easy reach.These features have been identified

and well demonstrated by AhmedabadStudy Action Group, a non-profitorganisation that has been working inLatur region for the past three yearswith the affected communities.

De-lamination in thick stone walls.

Unfortunately the massive rehabilitation programme which has essentially become areconstruction programme has brought in construction technologies which tackle onlythe need for safety while sacrificing all other needs that the vernacular housing

technology satisfies.


6/9


With a wide variety of groups at work there is a broad range of technologies at work.The technologies could be listed as....

Geodesicdomes -

Rehabilitation?

Corrugated GalvanisedIron sheet roof with

false ceiling supportedon hollow cementblock masonry walls.

RCC slab on hollowcement block masonrywalls

RCC slab on brickmasonry walls

RCC slab on RCCcolumns with brick orhollow cement blockwalls

RCC slab on RCCwalls

Sophisticated pre-cast concrete technology -Going over board with safety?

RCC slab on Cast in-situ hollow core RCC walls RCC slab on walls made of pre-cast hollow core RCC panels Ferro-cement Geodesic dome

These technologies are significantly more expensive than that based on local materials.As compared to US$26 ( July, 1994) per sq. m. as demonstrated by A.S.A.G. thesecost US$70 to US$110 per sq. m.

The problems posed by these alien technologies are as follows... High cost results in to very small, inadequate dwelling. Leaky RCC roofs require expensive water proofing. Todays CGI roofing degrades in five years. False ceiling invites rats and is difficult to maintain. Leaky RCC roof results in to rusting of steel bars which leads to breaking off of

concrete from underside.


7/9


RCC roof causes hotinterior temperature insummer nights.

In is impossible for thevillagers to drive nailsin to RCC walls. Thus

storage on wallsincluding hanging isnot feasible.

Inhollowcorewall snails or screws simplydo not hold. Thusstorage on walls is notfeasible

Quake resistant stone mud house - Appropriate option.

Hollow core slabs are alreadyshowing signs of rustingreinforcement.

Geodesic domes have little soundand heat insulation.

It is difficult to create partition undergeodesic domes for privacy for theoccupants.

Geodesic domes often developtemperature cracks which results into rain leaks.

Complicated and expensive tarfelting is required to make themwater proof.

All the above options make theconstruction of seismically safeextension to the house difficult andexpensive.

The geodesic dome permits nopossibility of expansion at rural level.

The plastered whitewashed walls

and ceilings darkened by soot fromwood burning stoves are difficult andexpensive to maintain.

Adobe construction with enhanced seismicresistance - Even poor can have safety.

Large windows will bring in a lot ofheat in summer and a lot of cold inwinter


8/9


Proud owner of retrofitted house -knee braces for added seismic safety.

Preparation for roof level RCC band onstone mud wall.

Taking care of all of theabove problems is beyondthe rural skills andresources. They will resultinto long term hardshipsthat the people will haveto simply bear. Thehouses that can not bemaintained will degraderather rapidly.

Retrofitted stone wall with RC bond elements to prevent delamination

One more drawback of these modern technologies is that they contribute very little, if atall, to the rural economy since the money invested in cement, steel and special skillsend up some where far away.

The house construction is an economic activity that simultaneously createsemployment. By resorting to technologies that depend upon distant resources theactivity contributes little to the local employment scene. In other words large-scaleconstruction as in Latur area had resulted into large scale unemployment of the

traditional artisans.


9/9


Expensive technologies use up scarce national resources for the benefit of far too fewhouseholds. Technologies more efficient in Indian context could benefit many morehouseholds.

Yet another critical issue is the water requirement of these technologies. In area likeLatur which is almost always water starved, being in the rain shadow of Western Ghats

mountain range, has little water to spare for cement based construction. Hence, thewater available is rarely adequate for curing needs. This leaves the structuressignificantly less strong than they are expected to be. Such weaker structures degraderapidly with time and may not be able to withstand the elements such as rain, wind andearthquake.

In short the wrong choice of construction technology results into....

Long term hardship to the occupants, shorter than th designed life of the structure, Reduced safety of the occupants, Drain of local resources, Local unemployment Uncertainty about future housing, Inefficient use of scarce resources.

Rajendra Desai,Consultant for Housing & Disaster MitigationAhmedabad Study Action GroupAhmedabad, Guj, India.

May 1997.

Documents

05 Latur Reconst & Technology Options