PCR TOOL 10
Quality of construction is a key factor in determining whether a building will withstand disasters. There is ample evidence to show that, when hazards of similar magnitude strike rich and poor countries, it is the latter which suffer more casualties. Similarly, within countries, the poor generally suffer more from a disaster than the rich. Poverty is an important factor in determining construction quality, however, it can be possible to considerably improve quality with relatively little extra cost. Experience from past reconstruction tells us that housing is built to varying degrees of quality, using various approaches to reconstruction. Donor-Driven Reconstruction (DDR), typically uses professionals for design and supervision, and contractors for construction, but does not always deliver adequate quality. However simply handing over total responsibility to home owners, through OwnerDriven Reconstruction (ODR) does not solve this, particularly if training and support is neglected. In People-Centred Reconstruction (PCR), people are in charge of the construction process, therefore quality control starts with them. They need to know why quality matters for building back safer, and have a basic knowledge of how to measure quality in the construction technologies they have chosen. This is easier if technologies
are chosen that are familiar. Building artisans also play an important role in ensuring quality of reconstruction by assisting in more specialist parts of construction. Although artisans may be in a position to help build back better, people need to be able to determine whether what they deliver is good quality. As in ODR, quality improvement does not happen spontaneously, but requires pro-active involvement of the supporting agency. The agency must determine, with the community, the existing skills levels of local actors and subsequently what training is needed to generate additional skills in building materials production, construction and quality control. They need to supervise and provide additional technical support to the construction process on a regular basis in order to make up for any deficiencies. Whilst training in construction and materials production is quite commonly provided in reconstruction projects, training in quality control is often neglected. This tool aims to help fill this gap.
Why is quality of construction important?
The quality of buildings is important to the occupants. Collapse of buildings is the most common cause of deaths, injuries and material damage in natural disasters. Evidence shows that a lack of quality in construction is a key factor in building collapse or damage. That is not to say that other factors, such as location, design or maintenance, can be ignored, but construction quality deserves special attention; for more on the design, see PCR Tool 8, Participatory Design. It is also clear, from past experience, that disasters affect the poor more than the rich, and there is a correlation between the quality of construction people can afford and its subsequent behaviour during a disaster. This apparent correlation, however, deserves further scrutiny at local levels. There is ample evidence that sometimes relatively poor people do build with technologies that resist disasters well and are not very costly; see also PCR Tool 3, Learning from Disasters. Certain vernacular technologies have evolved over centuries, and often taken on board disaster-resisting details in the process. For example, this is the case, in Pakistan, Peru and Turkey, where various timber frame technologies have been successfully adopted in
Poverty led to poor construction and maintenance in the Alto Mayo of Peru; when a moderate earthquake struck in 1990, it destroyed many houses such as this.
photo © Practical Action / Megan Lloyd-Laney
The poor are more vulnerable to disasters
When an earthquake measuring 6.9 on the Richter scale struck San Francisco on October 17th, 1989, it killed 62 people, affected another 3,757 and caused 5.6 billion US$ of damage. In contrast, a similar sized earthquake that hit Gujarat in India in January 2001, killed 20,005 people, left 167,000 injured and over one million homeless, at a slightly lesser loss of 5 billion US$. The next month, an earthquake measuring 6.8 just off the coast of Seattle, only killed one (from a heart attack, not building collapse), left 400 people injured and relatively few buildings damaged. But in 2003, the earthquake that affected Bam, in Iran, measuring only 6.6, killed 26,796, injured 30,000 and left 100,000 homeless. And the earthquake measuring 7.0 that struck Haiti on January 12th, 2010, killed a massive 222,570 (1 in 15 of the about 3.7 million affected) and injured around 300,000, many of those in the shanty towns of Portau-Prince; an estimated 1.5 million became homeless. In May the year before, a much larger earthquake measuring 7.9 struck Sechuan in China, killing 87,476 (only 1 in 595 of those affected) and injuring around 360,000 people; the damage caused was a massive 85 billion US$, but only about 240,000 were left homeless. Less than two months after the Haiti quake, on February 28th, 2010, one of the strongest earthquakes ever, measuring 8.8, hit Concepción in Chile; it only killed 562. See, for example. Suresh (2005) and the OFDA/CRED International Disasters Database, EM-DAT (http://www.emdat.be/naturaldisasters-trends, consulted on October 25th, 2010).
250,000 200,000 150,000 100,000 50,000 0 1 62 562 6.8 6.9 8.8 7.9 6.9 6.6 87,476 7.0 10 9 8 7 6 5 4 3 20,005 26,796 2 1 0 Magnitude of quake: Richter scale
Number of casualties
Each of these earthquakes struck relatively populated areas and the figures clearly indicate that in disasters of similar magnitude, rich countries suffer less than poor countries. Furthermore, within countries, the poorer neighbourhoods such as the shantytowns of Port-au-Prince are more affected. There appears therefore to be a correlation between poverty and disaster impact. Rich countries like the USA and Chile, are able to build to high quality standards, incorporating disaster-resistance. Besides, the majority of their population can afford to comply with these standards. Other countries, such as India, have adequate construction standards, but stark inequality within the population means many people cannot afford to build according to these standards. In most poor countries like Haiti, over half of the urban population cannot afford to build according to prevailing standards. They construct houses as best they can, but often their quality is inadequate to sufficiently withstand disasters. post-earthquake reconstruction (see case 3 in the Applications section). There is also a growing body of evidence that the cost of improving the disaster-resistance of buildings is relatively modest compared to the huge losses that can result from the impact of disasters on unprotected buildings (see: Benson and Twigg, with Rossetto, 2007). In Bangladesh, for example, it can cost only an additional five per cent to make simple modifications to improve the cyclone
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Reconstruction using dhajji dewari, a traditional timber frame wall, filled in with stone and mud, in Kashmir, Pakistan
Woman rebuilding a house in Chincha, Peru, using improved quincha; this is a relatively simple and familiar technology that self-builders can use with good results
resistance of traditional (kutcha) houses, while retrofitting hospitals against hurricanes in St Lucia and Dominica added only one or two per cent to the cost. However, the Gujarat earthquake in India caused an estimated five billion US$ in direct and indirect losses while Hurricane Mitch in Honduras in 1998 caused losses estimated at 41 per cent of GDP and Hurricane Luis in 1995 in Antigua and Barbuda led to losses equivalent to 65 per cent of GDP. Thus, there are ways of achieving quality, even when resources are scarce. This requires information about appropriate technologies, capacity building, and quality control. Finally, construction quality also matters to the agencies supporting reconstruction. They are accountable not only to their beneficiaries, but also to the donors who are funding them. Donors need to be reassured that their money has been well spent, and they will not have to finance more reconstruction in the same location in the future as a result of poor building. Thus, agencies and donors alike have to strike a balance between the quantity of houses they can build within a given budget (which determines the number of people they are able to reach), and the quality-standards these houses must reach in order to be disaster-resistant.
• The design must be such that building artisans and families can implement them. Preferably, technologies should be selected that they are familiar with. Where essential skills are lacking, training must be provided; • Building artisans, materials producers and families rebuilding their houses must be aware of the need for quality to ensure building safety, and have basic skills to control quality; • Building materials and components must be produced to an adequate standard and, where necessary, protected from climate and contamination during storage; • Agencies involved with PCR need to provide adequate technical support and supervision during construction works; • Further extensions to houses must utilise similarly safe designs and technologies. Technologies chosen for reconstruction therefore need to be affordable in the long run, not just in immediate reconstruction when extra external resources are available; • People must be able to maintain houses in a safe condition; • Reconstruction grants need to cover the cost of building according to an approved design and standard, and accommodate for inflation.
What to do to achieve quality of construction?
For houses and other buildings to stand up to future hazards: • All key partners involved in reconstruction need to be aware of the need to mitigate future disaster risks and have a basic knowledge of building structural features that can help with this; • The design must be structurally sound to withstand anticipated risks (see: PCR Tool 6, Participatory Design;
What may go wrong and reduce quality?
Past reconstruction experience tells us that projects often work out differently in practice than was expected. Below are some examples of where and how this has happened, how it has negatively affected reconstruction quality and how such mistakes can be prevented: • Housing plans, designs, specifications and guidelines drawn up by somebody with
photo © Practical Action Latin America
photo © UN Habitat
inadequate knowledge of the structural performance of buildings in disasters. To prevent this, structural engineers or suitably qualified built environment professionals need to check these documents, better yet, produce them themselves. Building materials and components passed as fit for purpose when they have not been checked adequately. It is important that materials and components can be traced back to source if a deficiency is discovered. Building materials or components not stored or handled properly resulting in deterioration or damage; it is particularly important to keep cement dry, to keep aggregates free from contamination (by wind, animals, children etc), and to protect timber from excessive sun and rain. Builders lack the technical skills to undertake the construction properly. It is important to assess the technical skills of builders in the area and to provide training to address deficiencies. Competent builders can be issued with certificates that show their level of proficiency. Site supervision may be lax. Supervisors must be aware of all the construction jobs to be undertaken. They need to be able to interpret drawings and specifications or instructions issued by professionals. They also must be able to communicate clearly with the builders. Supervisors given too many house construction sites to supervise. In post-tsunami reconstruction in Sri Lanka, the upper limit for a caseload was set at 100 houses, but some technical officers had to deal with 130 in two locations an hour apart; others were supposed to visit 25-30 sites per day. Under such conditions, supervision and support cannot be adequate. Builders take shortcuts to get a job done quicker or reduce costs; sometimes home owners do the same. This is particularly tempting when construction uses expensive materials such as cement or steel, a particular problem once concrete or mortar has set as it becomes more difficult to check its quality on site. Builders try to save in other ways, for example, not adequately curing concrete, mortar or stabilised soil whilst hardening, especially where water is scarce, or by mixing excessively large quantities of mortar in one go to continuously use for hours by adding small quantities of water. Inadequate inspection of building sites. Inspection is different from regular supervision in that it tends to be done at intervals only, often by an independent party. Its main aim is to check whether the work is up to standard
and in order to approve instalments of reconstruction grants. Inspectors may face other problems which can mean that deficiencies get overlooked: too many cases to deal with; lack of transport; unwilling to risk confrontation, or may themselves be corrupt. • Whilst there tends to be ample information on general construction, especially using modern materials, there is less on disaster-resistant building or on good vernacular construction. That which exists may be of questionable quality and not structurally verified. This lack of information affects those involved at all levels of safe building, from families to professionals.
Approaches to determining the quality of reconstruction
There are a number of approaches that authorities and agencies involved in reconstruction can take to come to a decision on the level at which quality control should be set. These range from: adopting international standards; adhering to a national regime already in place; setting regulations specific to a national reconstruction strategy; or allowing the people to decide on the desired level of quality. In People-Centred Reconstruction, it is important for those affected by disasters to have a say in the quality of construction that is adopted, as well as in the design and construction itself. If other stakeholders set quality at alternative levels that appear unachievable or unreasonable to the affected peoples, it can subsequently become difficult to obtain their interest and participation in projects. The most appropriate approach to adopt depends on the local context and therefore needs to be decided on a case-by-case basis. The issue of standards for reconstruction will be covered in more detail in a future PCR tool.
Quality Control in practice
Ensure that building materials and components used are of adequate quality
The use of materials that are poorly produced or inadequate for the intended purpose can be a significant factor in the collapse or damage of buildings in natural disasters. This can be a particular problem with materials produced by small enterprises, often in the informal sector, or those produced or gathered by residents themselves. As it is difficult to ensure the quality of materials produced in a decentralised way, some programmes consider pre-fabricating them in a few central locations where support and supervision can be provided regularly. However, even materials produced by larger formal enterprises may sometimes be sold without adequate checks, especially in the absence of national material standards.
Women making concrete girders for a housing project in Madaripur, Bangladesh
It is important for the engineers and architects involved in reconstruction to inspect the damage done by a disaster, together with local builders and residents (see PCR Tool 3: Learning from Disasters). This may highlight why particular buildings failed. If poor materials or components are suspected as a cause, these should not be used for reconstruction until a further investigation is carried out and steps taken to improve their quality. Where production has been to a poor standard, consider providing additional training to materials producers. In addition, the quality of materials produced needs to be closely monitored for at least half a year following training, and further spot checks taken after that. Any sub-standard batches must be discarded. If particular producers continue to regularly produce materials or components of poor quality, they need to be de-listed as suppliers. This approach is often the most suitable to stimulate the re-building of local livelihoods and markets. An alternative approach to addressing poor production standards is to identify a selection of
producers known to provide adequate quality and utilise only their products. Such producers could be selected by a project team, together with local builders and residents. Reconstruction, however, usually requires large quantities of materials, and in this case, this may mean that some producers may have to be selected that are much further away, or even abroad, with a less positive impact on the local economy. Residents and local builders will often have to purchase materials or components that are not locally produced, from shops in their area. It is therefore important that such building merchants or hardware shops are also made aware of the importance of quality of materials or components in a reconstruction programme. Ultimately, a project team could select or de-select such local shops in a similar way as it would with local materials producers, and only allow purchases to be made from the ones that qualify. A project team can only do so much to guarantee the quality of materials produced or supplied locally. Although it is ultimately the decision of residents and their local builders as to how to build their houses, it is important to raise awareness of the need to use good quality materials. The damage assessment after a disaster can help raise awareness, as it can open the eyes of those participating to what is good or bad practice and quality. In addition, a project team can provide some training on how to check the quality of local components and materials in simple ways. For example using visual means (is sand clean and sharp? Is timber straight?), touch (does the cement have any lumps?) or sound (do two fired bricks, when knocked against each other, make a clear ringing sound?). It is beyond the scope of this Tool to list such simple tests for the many materials that could be used in reconstruction worldwide. The information required for that can usually be distilled from standards or textbooks, but it will need to be translated into a format that is appropriate to local users (see PCR Tool 9: Communicating better building).
photo © Neil Cooper
Ensure that construction is of adequate quality
Poor quality of construction is another major factor contributing to collapse and damage of buildings in natural hazards. Similar to the materials, a damage assessment will often point out what is good and bad practice in construction. A reconstruction programme should, where possible, accommodate good local practice. Any technologies that performed badly in a disaster should be avoided in reconstruction, as should those building practices that contributed to collapse., However, it will be possible to improve on some through awareness raising and training, or some form of reinforcement,
Testing of the quality of bricks for a reconstruction programme for IDPs in the Vavunya area of Sri Lanka
photo © Singamuthu Jayesegaram
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