Infrastructure damage and economic losses due to natural disasters
All over the world, with increasing population, the construction of habitations, work areas and similar structures goes on at a fast pace. This is particularly true for the developing economies in Asia such as India, Srilanka, Nepal, etc. In order to save time and cost, many facilities are often constructed with ad hoc planning, poor workmanship, low quality materials and in a haphazard manner without much concern for systematic construction to attain quality and long term performance. When a natural disaster (earthquake, flood, tsunami, etc) strikes, many poorly constructed facilities collapse rapidly. Tremendous human and economic losses and infrastructure damage result from such natural disasters. Figure 1 shows two photographs of typical large scale infrastructure damages due to the recent strong earthquakes in Kathmandu, Nepal.
Natural disasters can destroy a large number of infrastructure systems covering habitats, educational buildings, industrial areas, etc. causing significant damage and losses in both public and private domains. For example, the damage and losses experienced by Tamil Nadu and Pondicherry States after the Indian Ocean earthquake and tsunami in 2004 were 2.45% and 4.02% of GSDP (i.e. Gross State Domestic Product). Also, very large financial inputs (in a short period of time) are required for the post disaster reconstruction efforts.
The issues with the current reconstruction approaches
Often the affected people are in a hurry to retrofit or rebuild the destroyed facilities to regain the original levels of functionality as early as possible. A few sections of the population may get appropriate shelters and other benefits in a short period of time. However, the general speed of reconstruction/rehabilitation is mostly not sufficient to meet the demands of large populations, especially the weaker sections of the society. For example, according TIME magazine, even after 5 years after the 2010-earthquake, there are many partly destroyed buildings around Port-au-Prince in Haiti with about 1.5 million people yet to be rehabilitated. In November 2014, the US Government Accountability Office reported that only about 900 houses have been built in Haiti using the USAID funds – as opposed to the initial plan of building 15,000 houses (CEPR, 2014). This is only about 6% of the target. According to the UNOSEH (2011) report, 357,785 Haitians are still relegated to living in the 496 tent camps throughout the country – indicating the ground reality of very slow construction process. Moreover, in the developing world, due to the poor and ad-hoc disaster management approaches, the qualities of the rebuilt systems are often very poor. Unfortunately, such reconstruction leads to a set of new infrastructure systems that are highly vulnerable to another upcoming disaster. This generally happens because of the absence of a time-tested system of construction, which would deliver quality projects in a quick, efficient and economical manner. Also, the sheer scale of the fast-track reconstruction activities could result in poor quality facilities if appropriate systems of construction are not adopted.
Precast Concrete Construction – A ‘System Construction’ technique for reconstruction
‘System Construction’ technique can be defined as a technique that can be established rapidly to deliver results with the required speed, quality and cost, and with excellent possibility of easy replication in large scale. Reconstruction of the destroyed infrastructure in the developing world would be a fitting example where ‘System Construction’ approaches would be of great use. The Precast Concrete Construction (PCC) technology is an excellent example of ‘System Construction’, which can lead to rapid reconstruction with good quality and reasonable costs. With the support of the Government of Gujarat, system construction has proved its worth in the rapid reconstruction (after the 2001 earthquake) of the Bhuj area in India. Similarly, the Government of Nepal can institutionalize a standard ‘System Construction’ scheme for rapid and large scale reconstruction of quality infrastructure, with large numbers of identical elements/systems (i.e. beams/columns/panels for mass housing projects, girders for bridges, etc.). In this article, the feasibility of the use of PCC for rapid reconstruction of quality infrastructure in earthquake-hit Nepal is explored and some suggestions for implementation are offered.
PCC is not a new development and has been in use for many decades for a variety of construction projects all over the world. In Eastern Europe and Russia, PCC was institutionalized to a great extent with a considerable degree of standardization and factory-based production to great advantage. The PCC technique is well-known and time-tested over many decades in various geographical areas including the UK, Finland, Malaysia, Singapore, South Africa, the USA etc. PCC is based on the concept of large- scale production of standardized building elements in a factory-like production centre, using standard designs and moulds. These elements are then transported to the construction site and erected using ‘System Construction’ methods, employing automation with various types of construction machinery. Precasting can be done generally with two types of building schemes: (1) Framed structural schemes with precast slab elements and (2) Large panel walls supporting the slabs (see Figure 3a and b).
Advantages of adopting Precast Concrete Construction (PCC)
In PCC technique, the concrete elements are precast in a factory/controlled environment in a parallel timeframe along with the development of the main construction site. This enables considerable savings in the overall construction time. The prefabrication can be done either by precasting in a specific yard nearby/outside the main construction location or in a standard production factory. With large number of repetitions covering many similar structures to be erected, the scale effect and the reduced overall construction period enable the optimisation of overall construction costs. The precast elements are of standard designs (with emphasis on good detailing) developed by an expert agency and produced in a factory under standard conditions.
This ensures a high level of quality control for the entire project. Once the complete system is developed and standardised, it is possible to rapidly procure the standard building elements from many geographically distributed production centres and use them for constructing large-scale projects in different geographical areas in a fast track manner. If an adequate level of standardisation has been attained, and if proper quality control is exercised in the various factories, it is possible to use products from different factories in the same structure in an interchangeable manner with required levels of functionality. Typical complaints on the use of precast concrete construction often arise from reduced levels of functionality, involving water leakages from outside, unsightly joints, etc. However, such issues are solely because of poor quality production, lack of standardisation and absence of System Procedures. With good designs and quality productions, precast concrete construction has delivered highly functional structures all over the world. These structures along with properly engineered and constructed connections between the precast elements can be designed to resist earthquakes and will have good durability over many decades.
Present status of Precast Concrete Construction in India
PCC has been prevalent in India for many years. However, its usage has been confined to only a few practitioners, who were well versed with Automation and System Construction techniques. Accordingly, the number of examples available for buildings constructed with PCC is very small. In the recent past, many Indian cities are adopting PCC for infrastructure projects such as the elevated sections of Metro Railway projects and large scale high-rise building/housing projects, very successfully (see Figure 4). Apart from captive precasting facilities set up near the construction sites (see Figure 5a) set up by some of the leading construction companies, around 50 manufacturing facilities (see Figure 5b) have been set up in the private sector all over the country. A noticeable area of growth in Indian precast industry is the widespread use of hollow-core slabs in building projects. Some international manufacturers of hollow core slabs are supporting Indian entrepreneurs to set up efficient specialist factories.
Many agencies (including IIT Madras) have pursued considerable research to identify the factors inhibiting the extensive usage of this highly utilitarian method of construction in India. Some of the factors inhibiting the growth of this industry in India are seen to be: (i) lack of official standards, (ii) levy of excise duty on manufactured precast concrete products, (iii) lack of appropriate transportation infrastructure for carrying large and heavy manufactured elements to construction sites, (iv) lack of a large number of precasting factories well distributed around the country, (v) poor encouragement from the government, etc. However, of late, many clients including real estate developers have realized the great potential of PCC and are now keenly looking to PCC to realize projects rapidly.
Recently IIT Madras had constructed a 2-storey house in Chennai with precast Glass-Fibre Reinforced Gypsum (GFRG) large panels in-filled with reinforced concrete (shown in Figure 6). This building having adequate seismic resistance and constructed in a short period of 29 days, is performing well at present. The Indian Concrete Institute (ICI), with support from IIT Madras, is on the verge of publishing a Handbook for “Precast Concrete Construction”. These developments augur well for the advancement of PCC in India. So much so that India may now be in a position to support neighbouring countries with technology for PCC.
Suggested methodology for using Precast Concrete Construction
After the recent devastating earthquake in Nepal, the speed at which Indian agencies (including IIT Madras and IIT Jodhpur) involved themselves for assistance, as well as the breadth and depth of such involvement, show the commitment India has towards helping its friendly neighbor. Continuing this altruistic tendency, India can also help in the reconstruction efforts, which are expected to be very extensive and which need to produce results very rapidly to provide shelters for the displaced persons. According to The Economic Times dated 17th May, 2015, the Government of Nepal have earmarked a NPR 200 billion Fund for reconstruction and have also mentioned that they would need huge expert foreign assistance. Possibly the Government of India can extend a line of credit to Nepal for the reconstruction efforts and this credit could be realised in the form of construction to be carried out by Indian agencies. However, there would be a need to ensure that the projects constructed would have the right functionality required, have proper quality, be economical and be constructed rapidly. The Government of India can set up a Task Force, possibly under the aegis of INAE (Indian National Academy of Engineering), to chalk out the steps required for such involvement. Typically, some of the steps required would be as follows:
– Study the ground situation in Nepal and identify the various types of structures required
– Identification of two or three typical standard structural schemes, which could be used for the buildings. Once the basic scheme is designed using modular concepts, the size of structures can always be modified quickly to suit the various requirements.
– Identification of good Indian Consultants to carry out the earthquake-resistant structural designs, evolving modular standards for the various elements and designing the connections to ensure good functionality, etc.
– Development of structural and material testing standards and mobilizing reputed testing agencies to ensure good quality control of the new construction.
– An enormous amount of construction debris is lying all over Nepal as a result of earthquake damage. Indian agencies have expert knowledge in the reuse of such debris as construction materials (such as coarse and fine aggregates) through appropriate segregation/crushing/ extraction procedures. This can be another advantage of using Indian expert agencies.
– Identification of Indian precasting agencies with the strengths and capabilities for precasting the required elements and tying up with them for supplying the specified elements with the required quality/quantity and as per stipulated timeframes. Special-purpose factories may have to be set up in Nepal at various locations to supply the elements easily at different geographical locations, which may not have good road connectivity with the rest of the country.
– Identification of Indian construction agencies with the strengths and proven capabilities for assembling the precast elements rapidly with adequate mechanization.
– Extension of tax incentives to minimise the costs.
– Coordination and supervision of the whole process to ensure that the projects are delivered satisfactorily.
In view of the critical requirements of precasting systems covering modularity, standardisation, and detailing of good joints / connections, it is necessary to have a holistic approach towards the entire project and bring in high-level experts and adequate supervision at every stage to ensure that the country’s name is not spoiled in poor execution of lofty ideals.
It is well known that Nepal has an urgent need for rapid reconstruction and may be finding it difficult to mobilize by itself the required resources in terms of technology and finance. In view of the advanced technology available in India, necessary assistance should be extended to our friendly neighbor expeditiously. Precast concrete construction would be the most appropriate technology to ensure rapid reconstruction with quality, economy and flexibility to cover a wide range of functionalities. An Indian government line of credit could support this assistance and such a large-scale operation for reconstruction would also benefit the Indian precasting industry to come out of its present status of low levels of utilisation. As the needs of Nepal are urgent, much time should not be lost to take the necessary steps to put in place an organization, which has the required expertise and agility for carrying out the above exercise.
– ADPC (Asian Disaster Preparedness Centre), “Social and Economic Impact of December 2004 Tsunami”, <http://cmsdata.iucn.org/downloads/social_and_economic_impact_of_december_ 2004_tsunami_apdc.pdf> (May 30, 2015)
– CEPR (2014) “USAID Houses Found to be of Poor Quality, Will Cost Millions to Repair”, The Center for Economic and Policy Research, <http://www.cepr.net/blogs/haiti-relief-and-reconstruction-watch/usaid-houses-found-to-be-of-poor-quality-will-cost-millions-to-repair> (May 30, 2015)
– The Economic Times (May 17, 2015) “Nepal to establish Rs 200 billion fund for reconstruction” <http://articles.economictimes.indiatimes.com/2015-05-17/news/62276975 _1_koirala-reconstruction-national-disaster> (May 28, 2015)
– The Times of India (May 9, 2015) “Team headed by IIT-Jodhpur director to help Nepal assess its quake damage” <http://timesofindia.indiatimes.com/city/jaipur/Team-headed-by-IIT-Jodhpur-director-to-help-Nepal-assess-its-quake-damage/articleshow/47210035.cms> (May 28, 2015)
– TIME (Jan 12, 2015) “Haiti Earthquake: Five Years After” URL: http://time.com/3662225/haiti-earthquake-five-year-after; (Last accessed on May 28, 2015
– UNOSEH (2011), “Has Aid Changed, Channeling assistance to Haiti before and after the earthquake”, United Nations Office of the Special Envoy Haiti, June 2011 <www.haitispecialenvoy.org>