Optimising Existing Structures Through Retrofitting
?Optimising ?Existing ?Structures Through Retrofitting
·??????Jit Kumar Gupta; [email protected]
Introduction
History of construction is said to be ?history of human civilization. Globally, construction sector is valued for leveraging economies, promoting industry and generating employment
When hit with disasters,?majority of existing structures face extensive damage, destruction and remain vulnerable due to improper design, poor quality of construction, lack of proper care and maintenance. This necessitates construction of new buildings, to compensate the ?buildings?damaged and destroyed. In addition, number of existing buildings are also being demolished and replaced by new structures. ?Demolishing ?and destruction of existing?buildings, causes colossal loss to the economy, environment, communities and nations. In order to minimize loss caused by the destruction/ demolition, it ?will be essential that not only quality of built environment is appropriately ensured, but also effectively monitored and efficiently maintained by ensuring ?time bound repair and maintenance. In addition,?mechanism of retrofitting also needs to be valued and adopted not only to?restore ?existing structures to their original health ?but also ?to ?put good structures to alternate use.
Retrofitting;
Retrofitting, as a concept and approach, had its genesis in the Second ?World War when weapons technology was advancing at an intense pace and planes/ ships were becoming outdated, even before their completion. Retrofitting was then found ?to be the option and applied to?completed craft with the addition/application of latest technology for ?making them appropriate for using them in the war. Retrofitting was later ?revived ?and made applicable to buildings, on a massive scale, during the energy crisis of the 1970s, when new features were added to millions of old houses to make them more energy-efficient. Later on, ?concept of retrofitting,?was ?extended to strengthen and make the structures safe against the damage?caused by natural disasters. Considering its?numerous and distinct advantages, retrofitting also became handy to be ?used for strengthening?existing structure to enhance its performance; restoring buildings to original health when structurally damaged by exposure to sun, rain, frost, water etc.; changing the use/typology of the structure from one purpose to another; improving the shear resistance and capacity of the structural members to resist seismic loads ; making addition of new technologies for improving the operational ?efficiency &reducing emissions?and making?structures safe against natural and manmade disasters. Retrofitting is extensively used for restoration, repairing and rehabilitating the heritage buildings, for maintaining their old glory and minimizing?damage caused , due to large number of people visiting them. Looking at the variety of damages caused ?and for ?making value additions ?to the structures, number
of options are being used for retrofitting. Five different typologies of retrofitting are ?generally used?for restoring the existing structures.
Typologies of Retrofitting;
·???????Energy Retrofit—Essentially includes and involves process of ?reducing the energy consumption to maintain the ambient temperature ; making existing buildings?energy efficiency and ?least consumers of energy, as compared to conventional buildings.?
·???????Disaster/Seismic Retrofit-- Includes the strengthening of the existing buildings to make them ?safe and resistant to disasters, both natural and manmade, involving earthquake/ cyclone/tsunamis/fire etc. Seismic retrofit is carried out primarily to protect; human lives and structures from total failure.
·???????Use Retrofit-- Process includes and involves, ?redefining the ?use ?and purpose of older buildings and to put them in new role/ order/use ?to meet the changed needs.
·???????Cultural Retrofit-Process followed ?involves?retaining/ restoring/enhancing ?the old glory and making value addition to ??historical /heritage ?buildings
·???????Storm water Retrofit--Process used for sites with?extensive?impervious surfaces ?to manage stormwater runoff?during rainstorms, to avoid?flooding and polluting?water bodies. Stormwater retrofit includes creating?rain gardens,?permeable paving?and?green roofs.
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Advantages
Retrofitting ?is known for its distinct advantage to the?owners, economy and communities, because it saves existing buildings from becoming obsolete, ?outdated and?possible ?damage and destructions. Retrofitting as a?process and mechanism, offers enormous advantages and makes value addition besides providing longevity to structures ?in terms of;
·???????Valuing ?existing structures?by ?avoiding demolition. Retrofitting the existing building ?invariably remains cost-effective?and time-efficient when compared with ?undertaking construction of new building.
·???????Making buildings sustainable
·???????Making buildings energy efficiency by bringing number of benefits to owners , tenants and occupants in terms of?reduced life-cycle operational cost.
·????????Increasing the market value of a buildings
·????????????Offering?most?economical and cost-effective option to ?increase the life?span of existing structures while preparing the buildings to?face adverse climatic conditions.
·????????????Strengthening the ?existing structure, abric and?saves on?the capital expenditure?while benefiting from new technologies
·????????????Making buildings economical?and owner/user-friendly, by reduced maintenance and increased reliability.
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Disadvantages of Retrofitting
Despite distinct advantages, retrofitting as a process , is also known for its ?limitations and disadvantages and accordingly needs to be used with care and caution. Retrofitting remains highly professional and scientific?process and??accordingly needs detailed study and analysis
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?the repair/remodeling and avoid ?any ?structural damage caused to the structure. The ?possible limitations of the retrofitting include;
·??????Retrofitting remains a time- intensive?exercise, due to?the need of ?detailed , in-depth , objective ,critical and expert analysis ?for?deciding about the extent of damage and options to be used for retrofitting.
·??????Retrofitting?needs high degree of precision and workmanship while undertaking repair. Minor ?mistake/irresponsibility ?in?execution can ?even cause?damage to the structure
·??????Retrofitting Heritage sites remains a highly demanding /high risk?time- consuming, cost-intensive and precision oriented process ??and accordingly needs trained manpower, ?appropriate expertise and ?thorough understanding of the basic fabric of the structure, materials and construction ?used in the building construction, for avoiding any disfiguring/damage to Heritage Site
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Analysis of Retrofitting
Before retrofitting any structure , it will be important to ?understand, consider, analyze and evaluate, critically and objectively, the status of ?existing structure in terms of its problems, deficiencies, damage and inadequacies, causes of the deterioration along with the symptoms which needs to be addressed to make building safe and usable. Only treating the symptoms, without proper understanding?the underlining cause of the problems, will invariably leads to camouflaging defects identification beneath the finished work. Analyzing existing?status of structure will require very specialized assessment and comprehension of the conduct of the?building, which is being fixed. Based on these studies and ?analysis, detailed strategy needs to be evolved in terms of process ,materials and method ?to be used for ?retrofitting. The choice to retrofit?a construction or its segments , needs to be made?after carrying out detailed ?cost- benefit analysis, based on?financial ?implications and availability of appropriate options for retrofitting. Steps involved in retrofitting should include; preparation of drawings and specifications of the building under retrofit; documenting condition, evaluation; determination of the main cause behind the deterioration;?selection of materials and methods of repair; execution process; maintenance after completion of the retrofitting work and checks and balance to monitor ?quality control during retrofitting.
.Prevailing Techniques for Retrofitting/Strengthening
Primary focus of retrofitting an existing structure is to increase its load bearing capacity with respect to its previous condition; improve the structural stability ; eliminate vulnerability of structure to any unforeseen disasters/shocks; improving its operational efficiency and changing the ?existing use/ operational framework of the structure. Established techniques which have been?used successfully for number of years ?have been ?recognized as ; Over Slabbing; Sprayed Concrete with Additional Reinforcement; Steel Plate bonding and External Prestressing.
Retrofitting has also been divided into two broad and distinct ?categories?ie Local and Global retrofitting. Local Retrofitting involves; jacketing of beams; jacketing of beam-column ?joints; strengthening individual footings and jacketing of columns, whereas Global Retrofitting includes; making addition of shear wall; adding infill wall; mass reduction and wall thickening. However, additional/ separate strategies will also be needed while changing the existing use of building for making it green or to meet the additional requirement of services and space. Options to be used for retrofitting will ?have to be based on the study and analysis carried out for the ?inadequacies and structural deficiencies ?existing in the ??building/structure ?to be retrofitted and appropriateness and suitability of the options selected. All the processes defined have their limitations, positivity’s, negativities, advantages and disadvantages and according choice has to be based on professional /detailed study and analysis.
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Way Forward
Retrofitting remains one of the best options to restore the existing derelict buildings to their original health and make buildings operationally efficient and usable for all human operations. Retrofitting should not remain confined?only to meet the structural inadequacies or?needs of repair and restoration. It?needs to be extended and taken forward by making use of its enormous capacity ?it provides to make buildings energy efficient and more livable. Retrofitting can help in reshaping, reframing?and putting to new use/options the existing structure, without ?resorting to demolition and?destruction. Potential of retrofitting has not been properly studied, understood, appreciated and exploited in the context of building industry to make existing buildings more livable, cost-effective, operationally efficient, ?having larger/ extended life-span?and reducing their adverse impact on the environment and ecology. It needs to be done on priority to make building industry more sustainable and least consumer of energy and resources besides generators of?minimum waste. Few of the options which can be leveraged ?to make buildings sustainable will include;
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·??????Achieving Sustainable Development Goal 11
UN has mandated that in order to promote global sustainability, cities ?will have to be made sustainable, safe , resilient and inclusive. Accordingly, a dedicated goal 11 has been made part of 17 SDGs to achieve the objective. Under the said goal, indicator 11-C has been included to make buildings Green, as part of making cities?sustainable. Further it has been mandated that by 2030, all nations will ensure to make?new construction to be net-zero and by 2050, all existing buildings will also be retrofitted to make them ?net zero-energy. Prime Minister of India has already committed in COP 26, to make?India Net Zero by the year 2070. Achieving?the said objective ?will be both difficult & impossible, without making buildings green and zero-energy.?Retrofitting offers?best option to achieve the target given by the Hon PM. Accordingly, it will be important for the professionals and professional institutes like IBC, IE, IIA to find out simple, cost-effective and time -efficient retrofit techniques to promote a culture of green buildings, both in new and old categories of buildings.
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·??????Retrofitting Existing Buildings to make them Sustainable ;
Buildings are known to be major consumers of energy and resources besides generators of the waste. Buildings also are known to be major determent of global sustainability. Statistically, there?exists more old buildings than new buildings, Majority of existing ?buildings remain highly energy inefficient. In order to ?promote energy efficiency; ?reduce carbon footprints ?and minimize energy demand in the ?existing built environment, it will be essential that in addition to making buildings structurally safe , ?it will also be critical?that concerted efforts should?focus on?making these buildings?energy/resource efficient and carbon neutral. Accordingly, energy efficient ?process/mechanisms of Retrofitting buildings, needs to be leveraged on large scale.
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Despite distinct and far reaching advantages offered, retrofitting has been used on a very small/limited scale to make the existing buildings?green and sustainable. Understanding the potential of retrofitting in making cities/buildings carbon-neutral; Singapore has?drawn a master plan to make all the existing buildings green through a collaborative policy framework involving residents, property owners and the government. The policy involves and includes,?adopting retrofitting as the process to achieve the defined objectives. Detailed ?retrofitting guidelines have been framed and norms defined,?for the existing buildings?to?make them sustainable.
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?In addition, in USA process of retrofitting has ?also been leveraged to reduce the energy consumption of high rise buildings; minimize their carbon footprints and reducing their heat island impact on the city and surrounding buildings. Retrofitting of Empire State Building of New York (one of the tallest structure globally) under the said initiative of the city, was led by replacing more than 6000 windows with double glass, rationalizing the air-conditioning system, generating solar energy; improving ?operational efficiency ?of chillers and rationalizing the requirement of air-conditioning, light and ventilation through artificial intelligence , which resulted in?achieving reduction of electricity load of the building to the tune of 3.5 MW and ?lowering greenhouse gas emissions by 1,00,000 tons over a 15 years period. The payback/recovery of the $13.1 million spent on retrofitting of building, has already been achieved in 3.5 years, due to lower connected electric load, ?saving on energy, lighting, air conditioning etc.
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In view of the above, Retrofitting needs to be ?promoted?and made mandatory ?to make ?existing buildings green, sustainable and least consumers of energy and resources. Considering the?large ?constructed buildings ?and?700-9000 million sqm of new?built space to be added annually in the urban India, local/state authorities need to?prepare a ?roadmap for each city and define the?detailed agenda and ?guidelines to make ?both existing/new buildings, green and energy efficient, using the process of retrofitting.
·??????Making retrofitting integral part of Study Curricula
Retrofitting, as an options to improve the operational efficiency and making built environment sustainable, does not find much favour with academic institutions involved in teaching-learning of designing, construction and management of?built environment and accordingly remains marginalized. This leads to professionals graduating, having low competency and understanding of the process and advantages of retrofitting. Considering the important role of the technology, it will be important that Retrofitting must be made and taught as integral part of the curricula as a separate and dedicated subject of study of the profession for promoting deeper understanding of the process and technique.
·??????Skilling Manpower in Retrofitting
Major roadblock in promoting Retrofitting as a methodology and a construction practice, is the non-availability of adequate number of professionally skilled manpower in the construction sector. Accordingly, it will be vital, that adequate opportunities for training and skilling ?the manpower in the ?art and science of retrofitting are created at the state/regional/local levels in order?to produce?large number of??professionally trained?competent manpower?required for Retrofitting, keeping in view ?immense potential and large demand generated by making existing buildings energy efficient and sustainable.
·??????Promoting Research
Considering the numerous advantages Retrofitting holds and opportunities and employment it can generate, by making value addition to the construction sector, it will be prudent on the part of all Academic Institutions engaged in imparting education in architecture, Engineering, Construction, Management; Development Authorities, Housing Boards, Improvement Trusts; Associations of Developers, Promoters and Builders, NARDCO; Parastatal agencies and?Urban Local Bodies to come forward, provide resources and create facilities ?and promote research in the area of Retrofitting of buildings constructed , in order to make buildings safe and sustainable. Even when the?nation has launched Housing for All ,as the goal to provide pucca house to all Indian national having no permanent shelter, it will be prudent on the part of the government to include Retrofitting as integral part of the PMAY, ?so that buildings constructed remain relevant and donot become obsolete in the fast changing physical and economic scenario.
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Consultancy in Retrofitting?also needs to be be?promoted to aid, advise, assist and guide the stakeholders in making buildings safe and to make value addition to existing buildings besides changing their?usage. A dedicated fund needs to be created?for focusing on R&D for the construction industry on the pattern followed in Singapore, where in the year 2007, Government launched a S$50 million “Research Fund for the Built Environment” to kick-start R&D efforts in sustainable construction
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·??????Redefining Construction Practices
?For construction sector to be really effective and efficient, its scope must not be limited to structural integrity and stability of buildings but should also ?include functional efficiency and safety of both users and occupiers. In majority of cases there does not exist any well-defined mechanism to keep a check on the quality of building during designing, construction and maintenance .For promoting quality built environment, it will be rational to evolve a detailed mechanism of checks and balances for promoting best construction practices and?adherence to process improvements.
?Learning ?from the collapse of Hotel New World, Singapore in March 1986, passed a legislation in the year 1989 , which mandated all construction projects to undergo mandatory checks at the stages of design, construction and completion of buildings. It also made mandatory for all construction projects to seek certified design reviews prior to the commencement of construction; independent construction supervision during the construction and periodic structural inspections of buildings, after completion, occupation and use of buildings; through the process of Periodic Structural Inspections (PSI). Conducting PSIs ensures early detection of structural defects, wear and tear of building which normally goes undetected and which ultimately leads to eventual partial or full collapse of the ?building. If ?periodic certification of buildings is conducted based on highest professional standards at the design, construction and post construction phases, then any subsequent rectification work becomes minimal. Periodic post- construction checks are also known to help in making buildings more cost- effective over its entire life span because of low cost of maintenance involved and longer life of building. Based on the Singapore experiences, it would be desirable that similar legislation in India also needs to be put in place on priority, to ensure that construction ?and maintenance of buildings is carried out in a most professional manner and built environment is made safe, qualitative, productive, inclusive and sustainable.
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Bibliography;
·??????The Future of Construction Sector in India,?Build Tech Magazine India -?September 9, 2016
·??????McKinsey Global Institute: “India’s Urban Awakening: Building Inclusive Cities, Sustaining Economic Growth”, April 2010
·??????World Green Building Council; https://www.worldgbc.org/what-green-building
·??????Wikipedia; Green Buildings; sustainable construction principles
·??????Wikipedia; Retrofitting; ?en.wikipedia.org/wiki/Retrofitting
Authors:
* Ar. Jit Kumar Gupta???????????????????????????????????????????????????????????
?Founder Director; College of Architecture, I.E.T, Bhaddal???
????????#344, Sector 40-A; Chandigarh- 160036??Email; [email protected]
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