The topic of this Ph.D. theis is repairing and strengthening of historical wagon vaults (barrel vaults, tunnel vaults) using post tensioning with tendons (monostrands) in longitudinal direction. The vaults should be without an edge, that´s mean the baroque vaults are well appropriate for this method. The pointed barrel vault should be problematic. The stabilization is for a wagon vault created by semicircle or segment part of a circle as well as an elliptic shape. The study has been made for vault with a width of 1 m and for the prestressing force has been used one tendon only. Of course, this method could be apply for normal constructions with a width of many meters. In this case, more tendons should be use with a suitable spacing. The goal of this work was to monitor an experiment model of an wagon vault and a real strengthened baroque vault of a church in Švábenice. During the monitor time, the static Analysis has been made. For these analysis appropriate finite elements in Ansys program has been use. The results of this work is to amplify the knowledge of the real behaviour of strengthened vaults, which could be use like instruction for the civil engineers. Further the public information guide to build an appropriate model of an Vault with an interaction with post-tensioning tendons.

Gamla Årstabron i Stockholm uppvisade efter 80 år i drift omfattande skador på de bärande betongkonstruktionerna enligt en utredning som genomfördes 2006 av dåvarande Carl Bro AB på uppdrag av dåvarande Banverket Region Öst. Det konstaterades att omfattande reparationer och förstärkningar av brons betongvalv var nödvändiga för framtida rationell drift av bron. Det beslutades efter vidare utredning att de första tre valven på Södermalm i Stockholm skulle renoveras med injekteringsbetong. Renoveringen av de tre valven på fastlandet på Södermalm var ett prov i full skala för att hitta den optimala metodiken för den fortsatta renoveringen av resterande 17 betongvalv. Det här examensarbetet syftar till att utvärdera metoden med injekteringsbetong med hänsyn till injekteringsbetongens egenskaper, material och produktionsteknik.   Bakgrunden till detta examensarbete är att det finns ett stort behov av att följa upp renoveringsmetoden med injekteringsbetong eftersom den inte har använts i någon större utsträckning i Sverige sedan slutet av 1970-talet. Utvärderingen av injekteringsbetongens egenskaper har utförts genom att analysera resultaten av de provningar som utförts på betongen. Provningen har gått till så att utborrade kärnor och tillverkade provkuber har provats för bland annat tryck- och draghållfasthet (vidhäftning). Utvärderingen av material och produktionsteknik har gjorts genom observationer på arbetsplatsen där rapportförfattaren praktiserade hos NCC under juni och augusti 2008. Utöver praktiken har jag närvarat vid och dokumenterat många av de injekteringar som gjorts under projektets första år.   Huvudsyftet med att använda injekteringsbetong var att få fram en betong som uppvisar tillräckligt hög tryckhållfasthet, en viss draghållfasthet och en fri krympning av högst 0,2 ‰. Tyvärr var inte provtagningen tillräckligt omfattande för att dra statistiskt säkerställda slutsatser gällande betongens egenskaper. Det som dock kan sägas är att provtagningen samt information från nyckelpersoner från beställaren (numera Trafikverket) tenderar att bekräfta det som konstaterats i de förstudier som gjordes innan brorenoveringen startade, nämligen att injekteringsbetongen uppvisar en klart lägre krympning än konventionellt gjuten brobetong. Vad gäller tryck- och draghållfasthet så uppfyller den färdiga betongen de krav som ställdes.   Blandning av ingående material i form av ballast och cementbruk samt de enskilda materialens egenskaper visade sig vara en kritisk punkt, vilket bekräftar det som framgår av litteraturen på området. Att kravet på renhet hos ballasten, stenmaterialet, är uppfyllt är av yttersta vikt för slutresultatet. Dessutom är det mycket viktigt att cementbruket som blandas med vatten precis innan det injekteras i den stenfyllda formen håller mycket hög kvalité och är stabilt. I vissa aspekter ställer också metoden högre krav på yrkesarbetare, platsledning och övrig produktionspersonal som pumpförare jämfört med att gjuta med konventionell betong. Förutom de enskilda gruppernas kompetens är också samordningen och logistiken på arbetsplatsen en mycket viktig faktor. Att använda metoden innebär dessutom att beställare och specialister måste ha kunskap och förståelse för att metoden ur vissa synvinklar skiljer från konventionell betong, särskild med tanke på den begränsade användningen av metoden i Sverige i modern tid.   Baserat på slutresultatet av renoveringen, de provningar som utförts samt omdömen från nyckelpersoner hos beställaren var injekteringsbetong rätt metod att använda för att renovera Gamla Årstabron. / According to an investigation conducted in 2006 by the former Carl Bro AB commissioned by the former Swedish railway authority (Banverket), the old Årsta bridge in Stockholm, Sweden, was  after 80 years in operation showing signs of extensive damage on the load-bearing concrete structures. It was pointed out that the concrete vaults of the bridge needed to be repaired and reinforced in order to keep the bridge in an operational state. After further investigation it was decided that the first three vaults on the north side of the bridge were to be renovated by using pre-placed aggregate concrete. The renovation of the three vaults on the north side served as a full-scale test to find the best possible methodology for the continued renovation of the concrete structures that consists of another seventeen concrete vaults. This thesis aims to evaluate the method of using pre-placed aggregate concrete regarding its properties and materials as well as the construction technology.   The reason for this thesis is that there is a great need to follow up the renovation method using pre-placed aggregate concrete since it hasn’t been used in any great extent in Sweden since late 1970’s.The evaluation of the concrete’s properties has been done by analyzing the results of the testing that has been performed on the concrete. Test specimens consisting of concrete cores and fabricated cubes have been tested for compressive and tensile (bond) strength. The evaluation of materials and construction technology has been done by practical observations on the work site where the author worked as an intern for the contractor NCC during June and August 2008. Apart from my internship I also attended and documented many of the grouting occasions during the first year of the project.   The main intention of using pre-placed aggregate concrete was to produce a concrete with high compressive strength, certain tensile strength and a free shrinkage of at most 0,2 ‰. The testing of the concrete was unfortunately not extensive enough to draw any unambiguous conclusions concerning the properties of the concrete. The results of the tests performed as well as information from key persons from the current Swedish traffic administration (Trafikverket) do however tend to confirm what was found during the pilot studies conducted before the renovation of the bridge started, namely that the pre-placed aggregate concrete has a much lower shrinkage than conventional concrete normally used in bridges. As for compressive and tensile strength, the pre-placed aggregate concrete meets the quality requirements.    The mix of included materials, aggregate and cement-based grout, as well as the properties of the materials themselves turned out to be critical for the result, which the literature in the field confirms. The purity of the aggregate is essential for the result. Moreover, it’s very important that the cement-based grout is of high quality and stable. When comparing with traditional concreting, the method imposes higher requirements on the workforce, management and subcontractors, in some aspects. Two other key factors, apart from the competence of each group, are the coordination and the logistics on the worksite. Using pre-placed aggregate concrete also implies that clients and specialists must have knowledge and understanding concerning the differences compared to traditional concreting, especially since the method hasn’t been used in any greater extent in Sweden the last 40 years.   Based on the result of renovation, tests conducted and reviews from key persons at the Swedish transport administration the decision to use pre-placed aggregate concrete was the right one.

Thesis (MEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The suitability of local construction materials for construction purposes is governed by several rock mechanical properties. Strength, durability, performance and petrography of aggregates all influence the decisions engineers make in deciding if the aggregate is suitable and sustainable throughout the lifetime of a structure. This thesis investigates these properties by combining engineering, chemistry and geological disciplines to make informed decisions. The pertaining project for which the research was conducted is the construction of the gravimeter vault at the Matjiesfontein Geodesy and Earth Observation Observatory (MGO) although the research acquired can be used for other projects of a similar nature and other outbuildings at the MGO. Material at and around the site were tested for strength and durability according to certain South African National Standards (SANS). Slake durability was tested as certain rock types tend to slake when exposed to the atmosphere such as tillite of the Dwyka formation and shale of the Karoo Supergroup. Concrete cube strength was determined on cubes containing crushed rock from Matjiesfontein as well as river sand. Cube strength was conducted to analyse performance and to establish a mix design that would be sustainable throughout the lifetime of the project. Petrographic examination using Powder X-ray diffraction (PXRD), X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM) and inspection under a petrographic microscope were conducted. These methods were used to determine if a risk exists for alkali-silica reactivity (ASR) in concrete when the rock types are used as aggregate, particularly if high quartz-bearing rock types such as quartzite of the Table Mountain group were to be used as coarse aggregate. Inspection of thin sections for strained quartz under a petrographic microscope and SEM imaging were important in determining if ASR may occur. The gravimeter vault was constructed using materials sourced mainly from Laingsburg. Tillite satisfied all tests and analyses conducted during the research, making it more suitable for construction than the other materials from Matjiesfontein. The slake durability test indicates that tillite is nearly as durable as quartzite, which is considered the most durable rock type at Matjiesfontein. This is due to atmospheric conditions in the Karoo being very dry with low humidity in comparison to the coast where slaking is known to occur. Slaking properties were most prominent for shale at Matjiesfontein and if excavated, it is recommended to cover the exposed shale with a layer of asphalt or cement to prevent slaking. The 10% fines aggregate crushing test (10%FACT) value for tillite was over the 210 kN prerequisite and the wet-to-dry ratio over 75% making it suitable for road construction according to the 10%FACT. All cube tests reached the desired 40 MPa prerequisite although the mixtures containing local river sand were unworkable. Unlike quartzite and quartzitic sandstone from Matjiesfontein, tillite is low in quartz and has minimal strained quartz. Therefore, no risk exists for ASR if tillite were to be used as aggregate in concrete. / AFRIKAANSE OPSOMMING: Die geskiktheid van plaaslike konstruksiemateriale vir konstruksiedoeleindes word deur sekere rots meganiese eienskappe beïnvloed. Sterkte, duursaamheid, volhoubaarheid en petrografie van aggregaat beïnvloed die besluite wat ingenieurs moet neem sodat die aggregaat aan standaarde voldoen en gedurende die leeftyd van ‘n struktuur volhoubaar is. Hierdie tesis ondersoek die genoemde eienskappe deur ingenieurs-, chemiese- en geologiese dissiplines te kombineer. Die voorgenome projek, waarvoor die navorsing ter sprake is, is vir die konstruksie van die gravimeterkluis by die “Matjiesfontein Geodesy and Earth Observation Observatory (MGO)”, alhoewel die navorsing ook gebruik kan word vir soortgelyke projekte, sowel as die konstruksie van die res van die geboue by die MGO. Materiale van die terrein en die omgewing is volgens sekere Suid-Afrikaanse kodes vir sterkte en duursaamheid getoets. Die blusbaarheid van materiale is getoets omdat sekere materiale, soos tilliet van die Dwyka-formasie en skalie van die Karoo Supergroep blus wanneer dit aan die atmosfeer blootgestel word. Die betonsterkte van kubusse, waarin plaaslike gesteentes en riviersand van Matjiesfontein vir aggregaat gebruik is, is bepaal. Die kubusse is getoets om die sterkte daarvan te analiseer en om ‘n betonmengsel, wat tydens die leeftyd van die projek volhoubaar is, daar te stel. Petrografiese eksaminering deur X-straal difraksie (XRD), X-straal fluoressensie (XRF), Skandeerelektronmikroskopie (SEM) en inspeksie onder ‘n petrografiese mikroskoop is gedoen. Met die doel om die petrografiese samestelling van materiale van Matjiesfontein te bepaal, is hierdie metodes gevolg om te uit te vind of daar ‘n risiko vir alkalie-silikaat reaksies (ASR) bestaan, as die gesteentes in beton gebruik word. Veral gesteentes met ‘n hoë hoeveelheid kwarts, soos kwartsiet van die Tafelberg-groep, is hier ter sprake. Inspeksie van dunsnitte vir gespanne kwarts onder ‘n petrografiese mikroskoop en SEM was belangrik om die risiko vir ASR te bepaal. Die gravimeterkluis is hoofsaaklik met materiale afkomstig van Laingsburg gebou. In vergelyking met die ander gesteentes by Matjiesfontein is tilliet, volgens alle toetsparameters, die mees geskikte gesteente vir konstruksiedoeleindes. Die blusbaarheid van tilliet vergelyk goed met kwartsiet, wat as die sterkste en duursaamste gesteente by Matjiesfontein, beskou word. Die rede hiervoor is die atmosferiese toestande wat baie droër is, asook die laer humiditeit in die Karoo, in vergelyking met gebiede nader aan die kus waar blusting meer algemeen voorkom. Die blusbaarheid van skalie by Matjiesfontein kom algemeen voor. As daar dus uitgrawing in hierdie gebied plaasvind, word dit aanbeveel dat ‘n laag sement of asfalt oorgegooi word om die blusting te verhoed. Die 10%FACT waarde vir tilliet was bo die vereiste 210 kN, asook bo die 75% nat-teenoor-droog-verhouding en daarom is dit volgens die 10%FACT-toets as padboumateriaal geskik. Alhoewel mengsels, wat plaaslike riviersand bevat het, onwerkbaar was, het alle toetsmonsters (kubusse) die vereiste 40 MPa- sterkte bereik. In vergelyking met kwartsiet en kwarsitiese sandsteen, bevat tilliet min kwarts en ook minimale gespanne kwarts. Daar bestaan dus geen risiko vir ASR indien tilliet van Matjiesfontien in die beton gebruik word nie.

<p> </p><p>The aim of this Master Thesis is to assess the load carrying capacity of the Glomman Bridge outside of the Swedish city Örebro. The Glomman Bridge is an unreinforced concrete single span arch bridge with backfill. The bridge was constructed in 1923 on assignment from the Swedish National Railways (SJ).</p><p>The failure criteria used in this thesis is that the bridge collapses when any cross section in the concrete arch reaches its ultimate capacity. In reality, the bridge may manage heavier loads than this. When the capacity is reached in a cross section, a hinge is formed and the arch relocates the forces to other parts of the arch that can carry higher stresses. The real bridge will not collapse until a fourth hinge is formed, and by that a mechanism. To be able to calculate the cross section forces in the arch, it was necessary to know the influences of the loads on the arch when they were run along the bridge. For this purpose, influence lines were obtained from a 2D finite element model created in ABAQUS, a general FE-analyses software. A calculation routine to find the least favourable load combination was then created in Matlab, a numerical calculation software. The routine was made to find the worst case among different load cases and to combine the standardized axle pressures with the present number of axles.</p><p>A parametric survey was also performed because the material properties for the different parts of the bridge are very uncertain. In the survey, the initial values were changed one at a time to study the outcome on the load factor. The load factor is the ratio between the ultimate limit load and the actual load. The studied parameters are the compressive strength, the Young's modulus, the density and the Poisson's ratio of the different parts of the bridge. The parameters are studied individually irrespective of possible correlation. The studied parts of the bridge are the backfill, the arch, the abutments and the asphalt. The clearly most important component is found to be the backfill. With increased stiffness or increased Poisson's ratio in the backfill follows increased load factor.</p><p>The equations behind the failure envelope can be derived from equilibrium equations for the unreinforced cross section. The influence lines are normalised with respect to the capacity of the cross section to get the degree of efficiency along the whole length of the arch, instead of the common influence lines that give the cross section forces. This is done because the failure is not caused by large cross section forces but by an exceeded ultimate stress. As the different loads are run along the bridge, the largest positive and negative efficiency for bending moment and normal force are localised. The normalised cross section forces are plotted together with the failure envelope and the load factor is then calculated.</p><p>Several masonry arch bridges were loaded until collapse in a study performed by the British Transport and Road Research Laboratory. One of the bridges in the study, the Prestwood Bridge, has been used in this thesis as a comparison to the Glomman Bridge. The load carrying capacity of the Prestwood Bridge is known, and is used to verify that the method using the failure envelope is applicable.</p><p>To compare the results from the cross section analysis from the failure envelope model to another method, the Glomman Bridge and the Prestwood Bridge were also tested in the commercial software RING 2.0. The method used in RING 2.0 differs from the failure mode in this thesis by calculating the load factor when four different cross sections reach their capacity and the bridge collapses.</p><p>The failure envelope method allows an A/B-value (Axle- and Bogie load) of 102 kN/147 kN when using very poor values of the parameters and 181 kN/226 kN when using a reference case with normal parameters.</p><p>Although the load capacity is found to be acceptable, the uncertainties are still large. To get a more accurate apprehension of the condition of the actual bridge, further research should be carried out, such as e.g. a non-linear model.</p> / <p>Syftet med föreliggande examensarbete är att uppskatta bärförmågan hos bron Glomman utanför Örebro. Glomman är en oarmerad betongvalvbro i ett spann med ovanliggande jordfyllning. Bron byggdes 1926 på uppdrag av Statens Järnvägar (SJ).</p><p>Brottkriteriet i detta examensarbete är att bron går till brott när något tvärsnitt i betongbågen uppnår sin kapacitet. I själva verket är det möjligt att bron kan klara tyngre last än detta. När kapaciteten nås i ett tvärsnitt uppstår en led och bågen omlagrar krafterna till andra bågdelar som klarar större spänningar. Den verkliga bron rasar inte förrän en fjärde led har utvecklats, och därmed en mekanism. För att kunna beräkna tvärsnittskrafterna i bågen, var det nödvändigt att känna till trafiklasternas påverkan på bågen när de kördes över bron. För detta ändamål erhölls influenslinjer från en tvådimensionell finita elementmodell skapad i ABAQUS, ett generellt FE-program. En beräkningsrutin för att finna värsta tänkbara lastkombinering skapades i Matlab, ett numeriskt beräkningsprogram. Rutinen utformades för att hitta värsta fallet bland olika lastfall samt för att kombinera standardiserade axeltryck med det aktuella antalet axlar.</p><p>En parameterstudie utfördes också då materialegenskaperna för de olika delarna i bron är mycket osäkra. I parameterstudien ändrades ingångsvärdena ett åt gången för att studera utslaget på lastfaktorn. Lastfaktorn är förhållandet mellan brottgränslasten och den verkliga lasten. De parametrar som studeras är tryckhållfastheten, <em>E</em>-modulen, densiteten och tvärkontraktionen för de olika brodelarna. Parametrarna studeras enskilt utan hänsyn till eventuell korrelation. De brodelar som studeras är fyllningen, bågen, fundamenten och asfalten. Den klart viktigaste komponenten visar sig vara fyllningen. Med ökad styvhet eller ökad tvärkontraktion i fyllningen följer ökad last­faktor.</p><p>Ekvationerna bakom brottenveloppet kan härledas ur jämviktsekvationer för det oarmerade tvärsnittet. Influenslinjerna normeras med avseende på tvärsnittets kapa­citet för att få ut utnyttjandegraden längs hela bågen. Detta görs då det egentligen inte är för stor tvärsnittskraft som orsakar brott utan för stor spänning. Högsta och lägsta utnyttjandegrad för böjande moment och normalkraft lokaliseras när de olika typlasterna körs över bron. Utnyttjandegraderna placeras i brottenveloppet för att sedan räkna fram en lastfaktor.</p><p>Ett flertal liknande broar har lastats till brott i en studie genomförd av British Transport and Road Research Laboratory. En av broarna i studien, Prestwood Bridge, har använts i denna rapport som jämförelse med Glomman. Då bärförmågan hos Prestwood Bridge är känd används den till att bekräfta att metoden med brott­enveloppet är tillämpbar.</p><p>För att jämföra resultaten från tvärsnittsanalysen i brottenveloppmetoden med en annan metod, testades även Glomman och Prestwood Bridge i det kommersiella programmet RING 2.0. Metoden som används i RING 2.0 skiljer sig från brottmoden i denna rapport genom att istället beräkna lastfaktorn när fyra olika tvärsnitt har uppnått sina kapaciteter och bron kollapsar.</p><p>Metoden med brottenvelopp tillåter ett A/B-värde (Axel- och Boggitryck) på 102 kN/147 kN när mycket dåliga parametervärden används och 181 kN/226 kN när referensfallet med normala parametervärden används.</p><p>Även om bärförmågan kan anses vara acceptabel är osäkerheterna stora. För att få en nogrannare uppfattning om brons faktiska tillstånd bör fortsatta studier utföras, som t.ex. en icke-linjär modell.</p>

Valvbågar är frekvent förkommande bland historiska byggnadsverk, då det är en gammal byggnadsteknik som tillämpats i flera tusen år. En metod att analysera och dimensionera valvbågar med är trycklinjeanalys. I detta arbete jämfördes två olika valvbågar, den uppmätta bärförmågan jämfört med bärförmågan enligt de teoretiska beräkningarna. Mätningarna utfördes på Linnéuniversitetet och beräkningarna utfördes i programvaran GeoGebra som baseras på trycklinjeanalys. Resultatet från det första testet visade att valvbågen hade en kapacitet på cirka 60 procent av den beräknade kapaciteten. I det andra testet uppnådde valvbågen en kapacitet på cirka 84 procent av den beräknade kapaciteten. Slutsatsen är att det är viktigt att vara noga med att rätt information sätts in i beräkningarna angående valvbågens geometri, om detta inte görs på rätt sätt är risken stor att analysen blir fel. Den viktigaste parametern att ta hänsyn till vid analysen är upplagsförhållanden för valvbågen. Ett sätt att ta hänsyn till eventuella avvikelser från verkligheten och beräkningarna skulle vara att implementera en säkerhetsfaktor i programmet. / Arches is frequently used in historic buildings, since it is an old building technique that has been applied for several thousand years. A method to analyze and design of arches is funicular analysis. In this thesis, two different arches were compared, the measured bearing capacity compared to the bearing capacity to the theoretical calculations. The measurements were carried out at Linnaeus University and the calculations were performed in the GeoGebra software, which is based on funicular analysis. The result of the first test showed that the arch reached a capacity of about 60 percent of the calculated capacity. In the second test, the arch reached a capacity of about 84 percent of the calculated capacity. The conclusion is that it is important to be careful that the correct information is inserted into the calculations regarding the arch geometry, if this is not done correctly, the risk is that the analysis will be wrong. The most important parameter to take into account in the analysis is the support conditions for the arch. One way to take into account any deviations from reality and the calculations would be implemented a safety factor in the program.

La 1ère partie de la thèse comprend trois volets. Le premier rappelle les connaissances générales sur la construction médiévale, en particulier le problème des plans. Ont été considérés plus en détail les plans du St­ Sépulcre d’Arculf et la reconstitution du temple futur de Richard de St ­Victor. Le 2nd volet fait le point sur les connaissances médiévales en mathématiques et en physique. Le 3e résume les théories sur la stabilité des voûtes développées du XVIIe au XXe siècle, par des mathématiciens et des ingénieurs, puis par des restaurateurs et historiens de l’architecture. La 2e partie est consacrée à l’étude de l’église de Brion (Maine ­et ­Loire), qui est remarquable par la qualité et la diversité de ses voûtes : en berceau sur le chœur, voûtes d’ogives primitives sur le transept, coupole nervée sur la croisée, voûtes à croisée d’ogives de type angevin sur la nef, et une voûte nervée complexe, apparentée à celles du chœur de St ­Serge d’Angers, au haut du clocher. La principale originalité de la thèse réside dans l’étude géométrique et mécanique de ces voûtes. L’analyse de modèles numériques réalisés par un procédé photogrammétrique a permis d’identifier la forme des voûtains. On a constaté notamment que ceux des voûtes d’ogives sont cylindriques, et que la direction des assises ne dicte pas leur géométrie. L’analyse mécanique utilise la théorie de l’élasticité. Elle a permis de montrer l’importance de plusieurs points : fonction des doubleaux qui soulagent la voûte en berceau, rôle de la colonnette centrale d’un fenêtre géminée, contraintes importantes qui apparaissent autour du trou de passage des cloches, fonctionnement des voûtes angevines comme des coupoles. / The 1st part of the thesis consists of three sections. Section 1 recalls the general knowledge about medieval construction, especially the problem of plans. Arculf’s plans of the Holy Sepulchre and the reconstruction of the future temple by Richard of St. Victor were considered in more detail. Section 2 is a review of medieval knowledge in mathematics and physics. Section 3 summarizes the theories on the stability of vaults developed from the 17th to the 20th century, by mathematicians and engineers, then by restorers and architectural historians.The 2nd part is devoted to the study of the church of Brion (Maine ­et­ Loire), which is remarkable for the quality and diversity of its vaults : barrel vault on the choir, primitive rib vault on the transept, ribbed dome on the crossing, Angevin type rib vaults on the nave, and a complex ribbed vault, similar to those of the choir of St­Serge in Angers, at the top of the bell tower. The main originality of the thesis lies in the geometrical and mechanical study of these vaults. The analysis of numerical models carried out by a photogrammetric method made it possible to identify the shape of the serveries. It has been found, in particular, that those of rib vaults are cylindrical, and that the direction of the courses does not determine their geometry. Mechanical analysis uses the elasticity theory. It has shown the importance of several points : the function of the transverse arches which support the barrel vault, the role of the mullion of a double window, the important constraints that appear around the bell hole, the Angevin vaults working as cupolas.

<p>ABSTRACT</p><p>Billions of people are living without access to safe hygienic means of personal sanitation. The sanitation gap is wide in developing countries where more people are increasingly becoming urbanised. Sanitation related diseases are some of the leading cause of mortality and morbidity among the population in developing countries especially children under age of 5 years. The responsible institutions are faced with challenge to provide suitable and affordable services to this increasing population. In Uganda, the urban poor are residing in the peri urban areas with inadequate sanitation facilities. The provision of conventional sanitation facilities are seen not be sustainable options due to contamination of both surface and underground water sources, congested housing structure and at the same time makes recycling and reuse of nutrients difficult.</p><p>This study investigated attitudes towards urine diverting toilets in one of the peri urban areas in Kampala, with the aim of finding out strategies to improve on awareness of ecological sanitation as well as popularise their use as alternative sanitation. Respondents’ views were collected through face to face interviews with 40 household respondents using a semi structured questionnaire and field observations of the household’s toilet in use as well as solid waste disposal. Four focus group discussions and 6 key informant interviews were also performed.</p><p>The respondents’ acceptance of the urine diverting toilets was relatively positive. Most of the respondents reported that the ecosan toilets are a viable option due to congested housing pattern, desire to own a toilet (for those who never had a toilet before), improved privacy, and convenience among other factors. Respondents who have no urine diverting toilets also preferred urine diverting toilets and expressed their willingness to replicate them. It was also found that residents in Kamwokya II parish prefer a double vault design to one which uses bucket. The findings also reveal that reuse of sanitized urine and faecal matter within the community is not possible since there is no space for urban agriculture. However, the respondents acknowledged a willingness to eat or buy food from a garden fertilized with sanitized urine and faecal matter. It was also found that there are no cultural and religious beliefs against reuse of sanitized urine and faecal matter. Some challenges that affected implementation of the pilot project were people’s reluctance to adopt at the beginning, delayed completion of some facilities and part time employees. Currently there is limited replication of toilets because of low cash income among the residents, delayed completion of some facilities and sceptical views by some residents.</p><p>Among the difficulties faced in use of toilet include forgetfulness by some people to spray ash after defecating, misplaced water entering the toilet vault during cleaning, children playing with the urine container etc. The provision for anal cleansing for Muslims, squat hole covers, closed urine chamber among others were suggested for system improvements. The study recommends more awareness campaigns through social marketing of toilet and reuse of nutrients, modification of design, government’s commitment and household change of behaviours are fundamental for encouraging more adoption and replication of the toilets.</p>