A lecture given by Randolph Langenbach that includes a large section on Haiti, is now available for viewing in its entirety on line at YouTube.com and Vimeo.com. 

CLICK HERE
to view video of the lecture

This slide presentation explores a comparison between traditional forms of construction and the most common contemporary construction type now used throughout much of the world – reinforced concrete with infill masonry. The session will discuss how one of the traditional construction typologies could form the basis for possible collapse-prevention improvements to standard reinforced concrete construction in earthquake areas, such as Sikkim, India, Van, Turkey, as well as earlier in Haiti and other parts of the world where many modern buildings have suffered pancake collapse.

This lecture includes a detailed discussion of Prof. Langenbach’s recent findings from his research using the PICTOMETRY oblique aerial photographs of the Port-au-Prince damage district.  This research has revealed an interesting fact:  the extent of the collapses – both in terms of total numbers of buildings collapsed, and amount of floorspace destroyed – in the downtown area of Port-au-Prince appears from the aerial documentary evidence to be much greater and more extensive than that found even in the informal settlements that ring the city – even though in both cases, the predominant construction is with reinforced concrete and cement block.  In the informal settlements, the often-photographed areas of widespread collapses were most often on steep slopes, where a lack of soil stabilization and retaining walls contributed to the failures, while the downtown commercial and residential buildings collapsed from failure of their superstructures, even though most had been constructed as a formal process, with design professionals and contractors.

This mission report documents the assessment process and outcomes, including mapping of the historic buildings, photographic documentation of damage, an online Gingerbread Damage Survey Database, a preliminary condition and repair feasibility analysis, recommendations for conservation strategies, and community workshops to advance the revitalization process.

This 85 page book is available in both English and in French as a free PDF from the World Monuments Fund website.  Please click on the title below.

English: Preserving Haiti’s Gingerbread Houses

Française: La préservation des maisons de style gingerbread d’Haïti

Clicking on title above will take you to the World Monuments Fund website where you can download a free copy.

NOTE: If you view it as a two-page spread, be sure to check “Show Cover during 2-up” on the  (on a Mac, it is “book mode” or words to that effect) in the View > Page Display Menu in the Acrobat Reader.  The Table of Contents and all odd numbered pages should appear on the RIGHT when you view the book correctly as designed.

CLICK HERE to read article

CLICK HERE to read article

The results of that meeting have just been published in PDF format, a copy of which is available here.  On page 17 and page 44, the document proposes that the Gingerbread Houses in Port-au-Prince located to the East of the National Palace be designated as an Historic District, and the preservation of the houses “should be supported.”  Here are the pages from the report.

To download the report, CLICK HERE:  COALITION REPORT: RECONSTRUCTION of PORT-AU-PRINCE

page 44 – To enlarge, click on image

page 17 – to enlarge, click on image

This meeting will be co-chaired by:
Dr.Steeve Ambroise assistant technical Director in charge of the building sector.
Kevin Rowell, Program Director for Kleiwerks International

With over 1.2 million Haitian in need of shelter in the short term and adequate housing in the long term, UN- Habitat and its partners invite you to participate in a Technical Working Group with aims at specifying opportunities for providing long term housing using building materials locally available to Haitians in various sectors.

In looking at other post disaster development in areas such as after the earthquake in Pakistan in 2005 lessons learned by the international community clearly indicate the need to focus on the improvement of traditional building technologies. Technologies that are economically accessible by larger portions of the population and rely on local, renewable resources. In the past 20 years much research has been conducted on the performance of these traditional materials including ones used extensively in the Haitian housing sector in Rural, peri-urban and urban areas.

Through this project we will provide methods that:

1: Evolve building construction with respect traditional architectural style and building methods.
2: Improve safety and durability of traditional structures made from local building materials.
3: Benefit local economies by improving homeowner and builders skills in providing safe, locally adapted, accessible and desirable housing.

The Goals of the technical working group at this point are:

Phase 1: Assessment: Duration = 2 months (Deliverables include a database of findings open to other organizations and a preliminary report on findings.)

This phase will focus on assessment of traditional construction methods related to providing housing in rural – peri urban and urban areas where the building methods relied on local materials. There are many documented examples of such buildings using earth and stone as primary building materials. Some of the research is already being compiled by members of this team as relates to buildings in the urban area of Port Au Prince specifically around “Gingerbread” style houses. This project to preserve these historical buildings was funded by the World Monuments fund, Prince Claus fund, Foundation Fokal and UNESCO. Through this proposal we hope to broaden the assessment research beyond historical preservation and include some of the other 12 identified building styles that utilize earth and other local materials in modern construction.

Phase 2: Technical Improvement: Deliverables include: Preliminary testing data, at least one formal Conference in Haiti, formalized report of technical findings and outline for phase 3

Through collaboration with national and international building trades experts our team will begin to draft opportunities for improvement of local materials based on recent international code specifications including the newly revised ASTM international Earthen Building standard. This will include a series of collaborative workshops to take place in Haiti and with design teams and community representatives from sample communities, as well as ministry, UN and partner NGO’s. In this phase Testing of traditional materials will be conducted in conjunction with the Haitian National Laboratory for Building and Public Works to certify test findings.

Phase 3 Dissemination: Duration (2 months) Deliverables: Basic training manual/program. A series of workshops involving 3 levels of parties. 1: Haitian government officials and NGO, INGO representatives, 2: Haitian building professionals including architects, engineers, contractors, builders, etc. A final summary.

Partners will conduct a preliminary series of workshops and trainings around the findings and conclusions of the research. The focus of trainings will include groups with the highest potential to further disseminate technical findings. The structure of reporting will be guided by UN-Habitat who will help to facilitate the dialogue with the Haitian Government concerning incorporation of the studies finding into guidelines and or best practices where applicable.

Whatever your organizations mid and long term goals are in the housing sector are we will benefit from having the right people at the table. Thank you for your consideration and we look forward to collaborating.

Jürgen Becker

Institute of Bio- Architecture & Ecology

Udayan, Auroville, India, 2010

Background

The construction industry is at present polluting & environmentally unfriendly at every phase, aside from failing to provide a good living quality. It contributes  30% of the CO2 emission in India even through it caters to only 40 % of the Indian population, mostly in the urban areas. The rural population still lives in traditional mud huts, which are ecological but lack modern amenities. The conventional building industry uses materials that are not only un- natural, but are also harmful pollutants in cases such as asbestos roofing sheets, chemical paints that produce volatile organic compounds (VOC) or steel frameworks. The resultant buildings are therefore not healthy.

The production of materials used in building is also energy-intensive. In addition, the common material cement requires high technology & is therefore expensive. In any case the burnt bricks and cement construction are unable to provide an optimal indoor environment, resulting in the occupants spending energy and money in cooling or warming the house. The disposal of building waste is also a major cause of pollution besides being expensive.

Earth is one of the oldest construction material known to man, available everywhere, and is a viable alternate to cement and fired bricks which are seeing an escalating rise in energy costs during production. Earth is also reusable, and can be recycled for many uses-including construction- after its life-cycle in a building without causing pollution. Further earth is good at regulating indoor room climate, as its pores absorb humidity when it is more and releases it when it is less. Similarly, when mixed with light aggregates earth can act as a good insulator regulating temperature in a building, as well as providing sound- proofing. New scientific findings show that earth is good at shielding against high-frequency electromagnetic radiation such as those emitted by mobile phones.

There are many ways in which mud can be used in construction – rammed earth, poured earth, adobe (sun-dried bricks & blocks) compressed bricks, as well as combined techniques in which earth is used in combination with other natural material. Of this techniques sun –dried bricks are most popular. This technique has evolved from the conventional brick- making process, but in which firing has been replaced by a degree of compaction and the use of stabilizer. When mud is used for construction, it is stabilized, with cement, lime or bitumen, besides commercial chemicals. Natural products – fiber or wood – have also been tried and used to produce mud bricks. Straw is the common natural reinforcing element that has been used to stabilize mud, for many decades in Germany, which has been a pioneer in the production of light mud bricks. Natural materials prevent cracking on being dried by spreading the stresses caused by the shrinking of the mud across the entire mass of the material & reduce the weight of the material, making mud a great deal less dense and also increasing the tensile strength of the bricks. Production of 1500 sun-dried stabilized bricks per hour has been achieved by using brick presses in Germany and Denmark. They can be successfully produced by large scale plants or small units using lighter equipment. As it requires little capital investment, it is also suitable for production by rural self- help groups.

Mud constructions are particularly useful for earthquake prone regions. Earth- quake proof houses can be solid construction using heavy and solid materials or made from light and flexible materials to produce resilient buildings. In the case of solid construction the structural stability derives from the stiffness and rigidity of the materials. If the stress caused by the quake becomes too extreme, the brittle material simply disintegrates and collapses. With lightweight and flexible constructions the earthquake stresses are eliminated horizontally and vertically through elastic deformation. This effect is substantially increased using mud, particularly when it is reinforced with coconut fibers.

The tropical alternative

However the materials and techniques developed in a particular socio-cultural and climatic condition are not interchangeable, so it is necessary to research with locally available materials as well as test known techniques to verify suitability to tropical conditions. Straw, the common reinforcing agent used in Europe is not suitable for tropical conditions as it gets fungus and its high cellulose content attracts insect pests.

After years of research, the Institute of Bio- Architecture and Ecology (IBE) has identified coir (coconut fibers) and coir- pith as the locally available natural material in the tropics that can be used with mud in construction. These have a high lignin and low cellulose content and are therefore more resistant to damage by insect, fungus and water. Coir- pith, which is the loose particulate present between coconut fibers, is an abundant waste product of the coir industry and  constitutes a pollution hazard as it does not decompose fast. Use of coir- pith in developing new products for construction would reduce pollution, as well as provide additional income to the largely rural based coir industry.

Besides use in bricks, coir and coir- pith can also be used to produce many kind of insulation material that can be used in conventional houses as well as in house made completely with mud, to regulate temperature & humidity, as well as sound- proofing. It is essential to look for ways to bring down energy costs to cool buildings by providing better insulation, as operational costs to maintain optimum indoor environment account for 80 % of the energy costs of a building in its life- cycle.

Our research task at IBE has been to find the right proportion between coir, coir- pith and mud for each product. Once the product specifications are ready, identification of the right technique and machines to be able to produce the articles on a large scale economically and ecologically, which is not energy intensive and that incorporates use of alternate energy sources, are undertaken.

Two coir-pith based clay products that have been developed, down to details of low energy production techniques are…..

Earthquake proof light-coir-pith bricks and blocks.

Earthquake proof inter-locking light mud bricks and blocks.

Current research focuses on Light mud- coir-pith insulation sheets.

Prefabricated light mud walls and panels in combination with coir and coir- pith.

The Institute of Bio- Architecture & Ecology has so far tested light coir-mud bricks and coir- mud mixture in combination technique in two experimental earth- quake proof houses that were constructed in Indonesia after the tsunami of 2004.

Theoretically one could use any material to construct absolutely earthquake safe buildings. Assuming that one designs and builds technically correct in a manner appropriate to the building material, absolute earthquake safety is only a matter of size, shape and proportions. These must be assessed differently for each material and construction method.

In reality things are rather different. Absolutely earthquake safe buildings are extremely rare. In most cases after an earthquake, it has been established that the injuries and deaths in a collapsed building can be blamed on the building contractor, the designer and finally the construction supervisor and are only indirectly the result of the materials and techniques used. Usually it is simply a matter of cost: corners are cut and regulations are not adherent to. This can only be tackled by continual and strict building controls.

Nevertheless evaluations of earthquake damage have shown that traditional buildings are less affected and also that the scale of their damage is far less than modern buildings for example, in particular multi- storey concrete constructions, which are known for their “ pancake effect”.

While even the smallest defect in a solid structure can be lethal- one thinks of the heavy bricks or wall and ceiling components that can cave in – defects in lightweight construction do not lead to such serious destruction and, above all, the victims can be rescued without the need for heavy lifting gear.

Experience with traditional buildings.

As investigations have shown, timber framed structures (wattle and daub, the behareque, and clay- daubed latticework) are the most earthquake resistant techniques. However, in some regions affordably-priced timber is not always available in sufficient quantities. In addition quite often people do not want this “cheap method for the poor”. In these cases it is better to adopt solid mud construction – either the adobe techniques, with different sized bocks, or as rammed earth: though it should be noted that all types of earthen construction depend on proficient design and implementation!

Earthquake proofing.

All right- angled changes in direction (example corner of a wall), whether horizontal or vertical, as well as all openings in a building are potential failure or weak spots in a building with regard to earthquake safety. Since not all right angles and openings can be avoided, the essential openings should only represent a maximum of one third of the wall surface or have commensurate proportions and should be correctly positioned (see Minke).

Use of round or segmental arches for windows and doors is recommended because these not only eliminate door and window lintels but also the right angles of the windows and doors. Using a template and appropriately beveled bricks/blocks, the archer is quite easy to construct, in load-bearing walls the doors and windows can easily be planned to occur between essential supporting posts.

Earthquake-resistant light – mud post- and beam- construction.

For the model house that was made in Indonesia, the timber post- and beam construction was chosen, since the requirements in Sumatra for earthquake safety are extremely rigorous. Furthermore flood protection also had to be taken into account.

The light- mud post and beam-construction suits these requirements particularly well and is also appropriate for tropical conditions. There are several reasons for this, including natural cooling principles, building materials and CO2 reduction measures. Traditional post- and beam construction techniques can be found in most countries and Indonesia is no exception. It makes sense to integrate these techniques as far as possible, for this makes construction simpler, faster and ultimately cheaper.

Framework infilling was achieved with a modified wattle and daub and willow lattice technique, whereby the horizontal and veridical elements (a right- angled grid structure) are strengthened by the addition of diagonal struts. Only in this way is triangulation achieved which, unlike the usual right- angled grid, does not deform. The first principal grid, with strut centers at ca. 20 to 30 cm, is formed with branches or laths of max. 2 cm thickness or with 2 to 3 cm wide split bamboo. The centers are reduced by weaving in additional thinner and shorter reinforcement struts.

Trough the horizontal, vertical and diagonal interweaving of the flexible reinforcement – which can be bamboo, but also any other wood or even branches – these stand under tension like an arch. These invisible forces ensure that the wall straightens up again after deformation (elastic distortion). The wall behaves like a feather. This elasticity is necessary, so that during an earthquake the forces that pass though the construction framework, imposing pressure on the infill panels, are absorbed and, through friction and by retaining elasticity, eliminate the distortion. Since the framework and the wattle of the infill are both timber, all the main physical elements match and harmonies.

The wattle is now filled from the bottom upwards with the mud mixture. The rich mud, which has already been tempered with coconut granules, is worked in by kneading into the coconut fibers, which have been twisted together into loose strands. These mud/coconut fiber strands of 15 to 30 cm length and approximate thickness of 2 to 5 cm are now woven into the wattle of horizontal, vertical and diagonal staves. After weaving these in, the individual strands are each pressed down onto the strand below and tightly consolidated from both sides by pressing with the flat hand and smoothed over. With this technique very thin walls of only 5 to 10 cm thickness can be made. Since there is hardly any mass to retain the heat, these are purely separating walls and quite sufficient for most domestic purposes.

The timber wattle is further stabilized through the interweaving of the mud/ coconut fiber strands. Since the coconut fibers consist of over 45% lignin, this building material also harmonizes excellently with the wood of the framework and the wattle. Due to the high proportion of coconut fibers, the elasticity of the walls is improved still further.

If the wall is not thin, nail and screws can be directly applied. Fatigue tests showed that the test samples did not break but when load applied they deflected so far that they slipped right out of the test rig. At the point where the bending occurred, although the mud crumbled, the coconut fiber held both components together.

Tests with models have shown that with this sort of construction, after a severe physical event (impact), the render only crumbles on the inside. This damage is therefore extremely easy to repair. The wattle and daub technique is by no means a technique only for the poor. It is also an outstanding method for luxurious and larger buildings.

Earthquake-resistant adobe construction

For the earthquake safe adobe technique too, coconut fiber and granules were used as reinforcement and as a tempering material for the bricks and blocks. The adobe bricks, in regular dimension (20 X 10 X 8 cm) or as blocks (50 X 20/25 x 15 cm), are supplemented with up to 30% coconut fibers and granules.

With the bricks and blocks we are talking about a fish- shaped interlocking system. Whereas most interlocking systems presuppose straight and right- angled building, the fish form is ideal for construction rounded corners, which eliminates a significant weakness: the right- angled corner. One can, of course, also achieve straight lines and right- angles, if one really wants to. But rounded construction are not only earthquake proof bat also hurricane proof. For Haiti on other imported point.

In the longitudinal axis of the bricks/blocks there is a ca. 2 X 2 cm groove along the middle. When constructing a wall, this groove is filled with clay mortar, as is the vertical groove on the end face and undersides of the brick/blocks. The hard, horizontal 2 x 4 cm clay core in the groove between the brick courses impedes lateral – horizontal – movement. To increase the friction between the bricks, I bond the bricks/ blocks together; to increase the friction is just to accommodate irregularities in the bricks and is needed to fill the horizontal and vertical

Grooves. The grooves core is joined on both sides to the vertical grove filling. In the roves one can place reinforcement rods, split bamboo for example. I favor coconut fiber strands. These are flexible and behave much like a sealing ring in a socket. They also adjust to the material better. Old chains placed in the grooves between the layers are also excellent for strengthening the corners. Because of the differing positions of the chain links, these are bonded firmly into the mud mortar and the bricks.

Apart from the construction technique, the reinforcement of the mud with coconut fibers is, in my opinion, the most important factor in the earthquake resistant method of construction described above. By adding coconut fibers and granules, the mud bricks and with them the wall becomes more flexible. Their behavior under compression also changes.

Under even pressure, the reinforced bricks and blocks does not break into small fragments but tolerates compression, where it is spreads out without fragmenting. When the pressure strain eases the block relaxes in accordance with the proportion of flexible deformation. The ratio of permanent and flexible deflection is determined by the addition of coconut fibers granules. The addition of these alters the physical properties of the mud products.

The higher the proportion of fibers and granules, the more wood-like the mixture becomes. Reinforced adobe blocks and bricks made in this way can accept nails and screws and are best worked using woodworking tools. This type of surface can be polished with sandpaper and treated with oils and waxes.

The supporting posts of a load- bearing adobe wall should project from the inside face of the building. In this way only one face is affected by water from the outside. Posts positioned on the outer surface, on the other hand, can become wet on three faces, which lead logically to faster saturation of post and consequent loss of stability. Although the earthquake resistance of post and beam structures is not affected by becoming saturated, an adobe wall rapidly loses its stability and bearing capacity.

This bricks and blocks are also suitable for infilling reinforced concrete skeleton construction. In the event of an earthquake, firm but nevertheless flexible contact with the frame ensures that the infill reacts to movements of the frame with elastic deformation without being destroyed or becoming displaced. Using these mud bricks for filling can stabilize the framed structure, since support capability is not influenced by the infill. Since the coconut fibers reinforced clay does not crumble like fired bricks or cement blocks but accommodates compression, the so-called pancake effect can also be avoided.

The earthen brick can be used as the infill, even in buildings that are not subject to earthquakes, anywhere in the world, to reduce energy wasted proportionally in construction and benefit from the cooling effects of earth.

Conclusions

Clay and earth can are still one of the most important building materials in developing regions. One- third of the world’s inhabitants live in earthen houses, where building houses – with mud – is part of the core skills in traditional societies. Modifying the materials and technique could ensure that clay would not loose it relevance in modern times and continue to be used, while providing sustainable answers to many problems created by conventional construction. Mud is a building material with a great past and a still grater future.