Study on Retrofitting of Heritage Structure: Construction & Problems

:- India is the land of heritage structure. It contains variety of heritage monuments and structure which are need to be conserved. Since we all know that India is country which is at high risk of been subjected to natural disaster such are earthquake, floods, cyclones etc more often every year in past 2 decade evidently. This phenomenon is increasing day by day. This paper draws the attention towards general problems encountered in development plan of heritage conservation. Heritages conservation lacks in methodologies used to rehabilitate, understandability of structural as well as material aspects. Also the economical aspects are another major part which hinders the initiative taken towards retrofitting of heritage building. Looking in scenario government of India has already started taking initiatives by making laws and making authorities appointing tasks etc. This paper discusses briefly about Geometrical layout & Material understanding of Heritage structure.

Although according to Natural disaster management Authority (NDMA) India has possibility to get exposed to high risk every year. i. Natural disaster such as cyclone or earthquake ii.
Erosion caused due to action of the hazardous materials. Also due to growth of vegetation on the buildings iii.
Damages due to aging and adverse environmental factors iv.
National priorities v.
Lack of cleanliness and Regular Maintenance RETROFITTING The process of upgrading the load bearing capacity of existing building to improve its structural performance is termed as Retrofitting. It's the method of restoring the lost strength of structure. There are varieties of Basic and advance techniques are available to retrofit any structure such Jacketing , Mass Reduction, Base Isolation, Bracing etc. So looking into the increase in damages and seismic activities many efforts had been made in past decades to restore the strength of heritages to make them capable to with stand seismic forces. Many cosmetic repairs run every day by the concerning authorities aiming to preserve the beauty of stones and material used in heritages (used in constructed by Kings). These repairs have helped the structure very well but repairing technique could not stay for long. They deteriorated the original material. Reason behind this failure was repair could not form the efficient bond with existing masonry. In several places the originality of structure has been totally vanished.

STRUCTURAL ASPECT
After studying the structural design of heritage structure many questions have raised in the minds of structure engineers. Although we have lot many heritage sites which are situated in the severe earthquake zone and cyclone prone areas (such as coastal region of south India) are still into existences, even after been hit by these natural disasters countless times in their life time. Past civilization had no structural intellect as it is available in today's world but looking into the giant structure constructed, true wisdom of architects and designers of ancient period are reflected. Understanding of structural design discovers that most of the existing heritage buildings are symmetrical in shape with their base wider compared to its top. It shows that in earlier period, the concept of symmetry was followed with a simple rule of physics which states that 'The resultant force of all the forces acting on the body should lie within middle third from the base region'. To assure the symmetry, the monolithic pattern of Arch and Dome can be seen commonly in Heritage structures. In common, the bases are made wider then top surfaces of monuments; it was done in order to trap the position of neutral axis within the base area when the high structure been subjected to disastrous thrust produced by winds and ground motion. This base enlargement was felt to be enough to accommodate the uplift cause by lateral forces.

MATERIAL ASPECT:
Apart for structure design the strength of building also depends upon the type and quality of material used for it construction. In earlier Period of time no man made material such as concrete and steel were available to resist the environment load and transfer them efficiently to the foundation. It is a big challenge for structural engineers to develop the knowledge about finding the similarities in type of material used since every other heritage sites are been constructed in different era by different civilizations which exhibits the unique authenticity of its own culture. So the material used in their construction are also as different as their periods of

Problem encountered with Material:
The material which was used by ASI in the repairing of Rumi Darwaza in Lucknow was failed after some time of application. The repair material which was used in construction did not fit with the quality and basic property of original material. Due to which whatever repair was applied was damaged again. This damage was even poorer as it was compared earlier.
Awadhi monument is made up of Lakhauri bricks and lime crushed brick aggregate. Mortar ratio is approximately 1:2 or 1:3 by volume.
The main reason behind the damage of repair work was variation is water absorption property.

Properties of original material:
Compressive strength of bricks used is approximately lies between 15Mpa to 17Mpa. Modulus of elasticity was found to be 5.7Gpa.Water absorption is almost 11.4%. Porosity was calculated to be 19.9%. Modulus of elasticity was determined to be close to 6.1GPa. Water absorption is 12.4 %.

Structural Test:
Structural test of Rumi Darwaza was conducted by the researches in order to make it stronger to with stand the seismic ground motion. During this structural analysis understandability lead the engineers towards the parts of structure which may damage due to ground motion. The crown area which contains major arch and dome was more vulnerable to stresses and moments caused to due seismic To make structure more seismically stronger the retrofitting of the structure was done using the modern technique of jacketing which has changed the original looks to drafted one.  Material : Properties of Lakhuri bricks used for The bricks are examined and the test report is below:- Mortar : Mortar was prepared using lime coarse sand and surkhi (ratio of 1:1:2). Hydraulic lime was used. Mortar used was also added with gur, urd, batasha, basen , juite, gum etc. to produce binding material. The thickness of mortar joint in this brick masonry was observed almost 2 times the size of brick.

Causes of Defect:
The caused behind these defects are following. Foundation: The whole monument rest over well type foundation filled with rubble masonry. The thickness of foundation is about 12m appox. The soil mass below it contains the sandy strata of 9.5 m followed by 65 m thick layer of clayey soil.

LAWS & ACTS
Many Law and Act are been passed by government in order conserve heritage and looks after the remains. Following are listed below i.
The Bengal Regulation XIX of 1810 and the Madras Regulation VII of 1817 are laws which were made in for heritage conservation. ii.
In 1863 Act XX was passed, which empowers the government to conserve structures of historical or architectural value.

iii.
The Ancient Monuments Preservation Act, 1904 permits government authority over privately owned heritage structures. iv.
The Ancient Monuments and Archaeological Sites and Remains Act 1958, passed for the preservation of ancient and historical monuments and archaeological sites and remains of national for the protection of sculptures, carvings and other like objects. v.
An amendment in 2010 provided for the constitution of the National Monument Authority charged with the grading and classifying of protected monuments and areas.

vi.
The Antiquities and Art Treasures Act 1972 was enacted for effective control over the moveable cultural property consisting of antiquities and art treasures.

vii.
India's commitment to heritage was further emphasized when it became a signatory to UNESCO's World Heritage Convention for the protection of global and national heritage. viii.
The Ancient and Historical Monuments and Archaeological Sites and Remains Preservation Act, 1956 of Uttar Pradesh provides for the "preservation of ancient and historical monuments and archaeological sites and remains in (the state) other than those declared by Parliament by law to be of national importance". ix.
In In India, to begin with, built heritage is under-funded by either public or private sources. Neither are banks and financial institutions keen in extending loans for the protection and development of heritage assets. Banks are wary about putting their money into heritage projects, as the financial viability of such projects is not always easy to establish. "Linkages between heritage conservation and economic development, particularly in the context of promoting tourism, are still being understood, leading banks to be cautious in funding urban heritage conservation projects" Cess from tourism receipt: Some heritage sites have the potential to generate tourism and their upkeep can help achieve financial viability.
International donors and crowd sourcing: It should also be possible to seek monetary assistance from the World Heritage Fund. Citizens could come forward with voluntary contributions of money, skill and expertise. Other means such as crowd sourcing could provide handsome sums of money. Heritage properties that are under private ownership pose a particular problem: as they are averse to the listing of their properties as "heritage", they do not fall under the purview of government conservation agencies.

CONCLUSION:
According to understandability of the past efforts of retrofitting Heritage buildings required to be so conserved as close to their original as possible.

International Journal of Engineering Research & Technology (IJERT)
ISSN: 2278-0181 http://www.ijert.org Compatibility with the existing material being repaired and adhesion must guarantee durable jointing effect. Compatibility of material refers to properties i.e. the mechanical, physical, rheological and chemical features of both the materials must correspond to each other.
Restoration work needs plenty of time and financial resources. During natural disaster where people have been killed and homes have been destroyed, in such a situation heritage structures will not be accorded the top priority. Due to this heritages are left for later to be given attention to.