Texte remanié de: Ph. D.--Syracuse university, 1991. / Bibliogr. p. 190-206. Index.

Texte remanié de: Diss.--München, 1992. / Bibliogr. p. 191-198. Annexes.

Texte légèrement remanié de: Dissertation--Martin-Luther-Universität Halle-Wittenberg, Wintersemester 2003/2004. / Bibliogr. p. 435-482.

Modern building procedures and requirements demand that the selection and stabilisation of soils for the purposes of rammed earth construction be better quantified. This study examines the relationships between soil properties, stabiliser treatments, and stabilised strength and density for 111 soil samples taken from sites in New South Wales (Australia), and develops new quantitative criteria for soil assessment, selection, and stabilisation. Laboratory measurements of soil particle size distribution, plasticity, and shrinkage were made for each soil. Various quantities from 0-6 % of lime, cement, and asphalt were added to the soil samples, and the resulting 230 specimens were compacted, and cured for 28 days. Determinations were made of the optimum moisture content, maximum dry density, and compressive strength of the stabilised material. The samples showed stabilised strengths ranging from 1.0-5.4 MPa, with a mean of 2.62 MPa, and densities from 1.44-2.21 t/m3, with a mean of 1.86 t/m3. The results show that over 90 % of the variation in stabilised strength and density of the samples is due to variation in soil properties, with differences in stabiliser type or stabiliser quantity being relatively minor. The most important soil properties explaining stabilised strength are linear shrinkage and plasticity index. These properties have been used to categorise the soils into three groups on the basis of their suitability for stabilisation as measured against a compressive strength criterion of 2 MPa. Favourable soils have shrinkages of &lt 7.1 % and plasticities of &lt 16 %, and 90 % of these samples passed the 2 MPa criterion. Satisfactory soils have shrinkages of 7.1-13.0 % and plasticities of 16-30 %, and 65 % of these samples had strengths in excess of 2 MPa. Unfavourable soils have shrinkages of &gt 13 % and plasticities of &gt 30 %, and only 10 % of these samples exceeded the 2 MPa value. Soils in the favourable and satisfactory categories can be further discriminated using textural information. On that basis, all soils classified as favourable, and those classified as satisfactory and which also have sand contents &lt 60 %, are recommended as being suitable for stabilisation. Soils not fulfilling these criteria are unlikely to be successfully stabilised and should be rejected. These results stress the importance of selecting a soil favourably predisposed to stabilisation. Field techniques to search for such soils could be refined on the basis of the new soil criteria presented. Use of the criteria should also minimise unnecessary laboratory testing of the density and strength of soils that subsequently prove unsuitable for stabilisation. A flow chart is presented to guide practitioners through the different stages of soil testing, assessment, and rammed earth stabilisation.

Cette thèse est centrée sur les délibérations du tribunal de la Mercanzia de Florence. Pour les Florentins, l’accès au port de Pise, dont il est indirectement possible de reconstituer le trafic, est crucial et transcende les relations compliquées entre les deux villes. Mais, s’ils sont prêts à quitter Pise (1356-1369 et 1399-1406) ou à déclencher des guerres (1362-1364 et 1397-1398) pour défendre leurs exemptions de droits de douanes et de gabelles, leur analyse précise prouve la faible incidence sur les prix de vente. Ces sommes sont en réalité transférées à la nation florentine, dont la direction est bicéphale (un consul pisan, un notaire-syndic florentin). La découverte d’un statut de la nation (1381) permet de mieux connaître le rôle des dirigeants et la conservation d’un livre de compte (1374-1382) éclaire leur rémunération. Les structures communautaires sont centrées sur le fondaco de Porto Pisano, géré par la commune pisane, et sur la loggia, située dans le palais du seigneur de Pise de 1369 à 1392, ou 1395, date à laquelle la nation est transférée à Livourne et Piombino. Une double certification de la citoyenneté, par le serment de deux marchands et par l’envoi de lettres de la Mercanzia, est également mise en place. Les listes des traités bilatéraux ne recensent que les compagnies habilitées à prêter serment, ce qui rend difficile la prosopographie de la communauté. Le dernier chapitre montre la formation d’un champ judiciaire commun, capable de fonctionner durant les périodes de tension, à travers l’examen des procédures et du règlement de conflits concernant les franchises de taxes, le règlement des faillites et l’application du droit de représailles. / This PhD thesis focuses on the Deliberazioni of the Florentine court called Mercanzia. Access to the port of Pisa, the traffic of which can indirectly be reconstructed, is essential for Florentine people and transcends the difficult relationships between both cities. They are ready to leave Pisa (1356-1369 and 1399-1406) or to go to war (1362-1364 and 1397-1398) to defend their tax and customs exemptions, but an analysis of the specifics shows a weak impact on prices. These sums are transferred to two-headed Florentine natio (one Pisan consul, one Florentine notary-sindaco). The discovery of the natio’s statute (1381) improves our knowledge of the managers’ duties and the remaining accounts shows how they are paid. The structures of the community are concentrated on the fondaco of Porto Pisano, which is administrated by the Pisan city-state (commune), and on the loggia, located in the Pietro Gambacorta’s palace in Pisa from 1369 to 1392, or 1395, the year when the natio was transferred to Livorno and Piombino. Double certification of citizenship, first by an oath sworn by two merchants, second by the sending of letters by the Mercanzia, does exist. Lists in bilateral treaties only register the companies, whose members are able to declare one’s citizenship under oath, which makes the prosopography of the community even more difficult. The last chapter analyses the formation of a common judiciary field, able to function in times of strained relationship, through the presentation of bilateral procedures and of cases of conflict about tax exemptions, bankruptcy and reprisals.

Guiron le courtois, vaste roman de chevalerie en prose composé du Roman de Meliadus et du Roman de Guiron a été copié, remanié, compilé dans de nombreux manuscrits depuis sa création, entre 1235-1240, jusqu'à la fin du Moyen Âge. Sa matière ouverte à toutes les continuations en fait une œuvre aux contours flous. Le manuscrit BnF fr. 340 (fin XIVe-début XVe siècle), associant le Roman de Meliadus et la Compilation de Rusticien de Pise, forme un ensemble où se dessine la chevalerie errante des pères des grands héros arthuriens, animée par la violence des combats, l'abondance du sang versé, mais aussi par la joie des rencontres et de la parole échangée. C'est cette communauté vivante que cette thèse entreprend d'analyser, à travers l'exploration conjointe du texte et de l'image du manuscrit BnF fr. 340, dont l'analyse iconographique sera ouverte à d'autres programmes de manuscrits de la même période

Rammed earth is one of the earliest building materials used for structural walls. Stabilised rammed earth is a variant of traditional or pure rammed earth that involves addition of a small amount of cement to improve strength and durability. Rammed earth buildings experience in-plane shear forces as well as flexural stresses due to out-of-plane bending especially during earthquakes. The thesis attempts to examine the behaviour of cement stabilised rammed earth wall elements and building models subjected to lateral loads. A brief introduction to rammed earth construction followed by a review of literature on rammed earth and details of the existing codes of practice on rammed earth is provided in Chapter 1. Chapter 2 deals with the flexural strength, modulus of rupture, stress-strain relationships and free vibration characteristics of cement stabilised rammed earth (CSRE) in greater detail. Properties of raw materials used in the experimental investigations followed by a detailed description of the experimental programme, method of preparation of various types of specimens and their testing procedures are provided. Flexure strength and modulus of rupture were determined in both the orthogonal directions. Influence of (a) thickness of the specimen, (b) direction of compacted layers with respect to the flexural tension developed and (c) effect of cement slurry coating between the compacted layers on the flexural strength of CSRE were examined. The investigations show that flexure strength increases with the increase in the specimen thickness and a coat cement slurry on the compacted layers leads to improvement in flexure strength. The flexural strength parallel to compacted layers is higher when compared to flexure strength perpendicular to compacted layers. Stress-strain relationships show that the initial tangent modulus of CSRE in saturated condition is about 60% of that in dry condition. Damping ratio as obtained from the free vibration studies is found to be 0.022 in the two orthogonal directions. Dynamic characteristics of CSRE building models are presented in Chapter 3. A simple alternative to shake table called as “Shock Table” was used in the present investigation for providing base motion to the building model. A half-scale CSRE building model with R.C lintels only above door and window openings (with no earthquake resistant features) was constructed on the Shock Table. The wall thickness of the building model was 100 mm. Procedure for construction, instrumentation and testing of the CSRE building model is presented. Responses measured and damages observed are discussed in detail. Finite element (FE) analyses were performed on six different building models with different earthquake resistant features using commercially available FE software (NISA V17). Both free vibration and forced vibration analyses were performed. Natural frequencies and forced vibration responses (acceleration) of building model (BM1) obtained from experiment and FE analysis were compared. Responses (free vibration and forced vibration) of other five building models were predicted using FE analysis. Crack patterns of the building models with roof and without roof are compared. The thesis ends with a summary of the results and concluding remarks in Chapter 4.

Rammed earth is a technique of forming in-situ structural wall elements using rigid formwork. Advantages of rammed earth walls include flexibility in plan form, scope for adjusting strength and wall thickness, variety of textural finishes, lower embodied carbon and energy, etc. There is a growing interest in the construction of rammed earth buildings in the recent past. Well focused comprehensive studies in understanding the structural performance of rammed earth structures are scanty. Clear-cut guidelines on selecting soil grading and soil characteristics, assessing strength of rammed earth walls, density strength relationships, limits on shrinkage, standardised testing procedures, behaviour of rammed earth walls under in-plane and out of plane loads, etc are the areas needing attention. The thesis attempts to address some of these aspects of cement stabilized rammed earth for structural walls. Brief history and developments in rammed earth construction with illustrations of rammed earth buildings are presented. A review of the literature on rammed earth has been provided under two categories: (a) Unstabilised or pure rammed earth and (b) stabilised rammed earth. Review of the existing codes of practice on rammed earth has also been included. Summary of the literature on rammed earth along with points requiring attention for further R&D are discussed. Objectives and scope of the thesis are listed. The thesis deals with an extensive experimentation on cement stabilised rammed earth (CSRE) specimens and walls. Four varieties of specimens (cylindrical, prisms, wallettes and full scale walls) were used in the experiments. A natural soil and its reconstituted variants were used in the experimental work. Details of the experimental programme, characteristics of raw materials used in the experimental investigations, methods of preparing different types of specimens and their testing procedures are discussed in detail. Influence of soil grading, cement content, moulding water content, density and delayed compaction on compaction characteristics and strength of cement stabilised soil mixes were examined. Five different soil gradings with clay content ranging between 9 and 31.6% and three cement contents (5%, 8% and 12%) were considered. Effect of delayed compaction (time lag) on compaction characteristics and compressive strength of cement stabilised soils was examined by monitoring the results up to 10 hours of time lag. Influence of moulding water content and density on compressive strength and water absorption of cement stabilised soils was examined considering for a range of densities and water contents. The results indicate that (a) there is a considerable difference between dry and wet compressive strength of CSRE prisms, and the strength decreases as the moisture content at the time of testing increases, (b) wet strength is less than that of dry strength and the ratio between wet to dry strength depends upon the clay fraction of soil mix and cement content, (c) saturated moisture content depends upon the cement content and the clay content of the soil mix, (d) optimum clay percentage yielding maximum compressive strength is about 16%, (e) compressive strength of compacted cement stabilised soil increases with increase in density irrespective of cement content and moulding moisture content, and the strength increases by 300% for 20% increase in density from 15.70 kN/m3, (f) compressive strength of rammed earth is one - third higher than that of rammed earth brick masonry and (g) density decreases with increase in time lag and there is 50% decrease in strength with 10 hour time lag. Stress-strain relationships and elastic properties of cement stabilised rammed earth are essential for the analysis of CSRE structural elements and understanding the structural behaviour of CSRE walls. Influence of soil composition, density, cement content and moisture on stress-strain relationships of CSRE was studied. Three different densities (15.7 – 19.62 kN/m3) and three cement percentages (5%, 8% and 12% by weight) were considered for CSRE. Stress-strain characteristics of CSRE and rammed earth brick masonry were compared. The results reveal that (a) in dry condition the post peak response shows considerable deformation (strain hardening type behaviour) beyond the peak stress and ultimate strain values at failure (dry state) are as high as 3.5%, which is unusual for brittle materials, (b) modulus for CSRE increases with increase in density as well as cement content and there is 1 to 3 times increase as the cement content changes from 5% to 12%. Similarly the modulus increases by 2.5 to 5 times as the dry density increases from 15.7 to 19.62 kN/m3 and (c) the modulus of CSRE and masonry in dry state are nearly equal, whereas in wet state masonry has 20% less modulus. Compressive strength and behavior of storey height CSRE walls subjected to concentric compression was studied. The results of the wall strength were compared with those of wallette and prism strengths. The wall strength decreases with increase in slenderness ratio. There is nearly 30% reduction in strength as the height to thickness ratio increases from 4.65 to 19.74. It was attempted to calculate the ultimate compressive strength of CSRE walls using the tangent modulus theory. At higher slenderness ratios, there is a close agreement between the experimental and predicted values. The storey height walls show lateral deflections as the load approaches failure. The walls did not show visible buckling and the shear failure patterns indicate material failure. The shear failures noticed in the storey height walls resemble the shear failures of short height wallette specimens. The thesis ends with a summary of the results with concluding remarks in the last chapter.