Drystone walls have been used extensively around the world as earth retaining structures wherever suitable stone is found. Commonly about 0.6m thick (irrespective of height), there are about 9000km of drystone retaining walls on the UK road network alone, mostly built in the 19th and early 20th centuries, with an estimated replacement value in excess of £1 billion[1]. Drystone wall design is traditionally empirical, based on local knowledge of what has worked in the past. Methods vary from region to region, driven by both custom and the nature of the materials available. Design is not necessarily optimised, and includes unknown margins of safety. There is a recognised need for guidance on the assessment and maintenance of dry stone retaining walls, as no suchdocumentscurrentlyexist. Thisthesisdocumentstheconstructionofaseriesoffull-scaletestsdesignedto provide sufficient information to validate current theoretical and numerical analysis techniques. The development of a unique test rig is detailed, in addition to the testing regime and results from a programme of five 2.5m high drystone retaining walls. The walls were subjected to localised surcharging and foundation movements, recreating the conditions that many in-situ walls are subject to. Movements such as toppling, bulging and sliding were observed, and recorded using a broad range of instrumentation. This has provided high quality, quantitative data relating to the factors which influence these mechanisms, and their affect on wall stability. Also documented are the associated laboratory tests which have been conducted to determine the mechanical properties of backfill and the walls themselves, as well as the manner in which they interact together. To assist in the analysis of these full-scale tests, a limit equilibrium program has been developed. This package allows the rapid generation of a wall of any size and constructed with any materials. The limit equilibrium program has then been used in conjunction with the data from the full-scale and laboratory tests to analyse observed drystone wall behaviour. These include the phenomena of toppling, bulging, bursting, sliding and individual block rotation. In each case, the underlying causes of such movements have been determined, and the critical parametersidentified.

Digitized by Kansas Correctional Industries

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This study concerns the strength and behaviour of low-rise shear walls made from high-strength concrete under reversed cyclic loading. The response of such walls is often strongly governed by the shear effects leading to the shear induced or brittle failure. The brittle nature of high-strength concrete poses further difficulties in obtaining ductile response from shear walls. An experimental program consisting of six high-strength concrete shear walls was carried out. Specimens were tested under inplane axial load and reversed cyclic displacements with the test parameters investigated being longitudinal reinforcement ratio, transverse reinforcement ratio and axial load. Lateral loads, lateral displacements and the strains of reinforcement in edge elements and web wall were measured. The test results showed the presence of axial load has a significant effect on the strength and ductility of the shear walls. The axially loaded wall specimens exhibited a brittle behaviour regardless of reinforcement ratio whereas the specimen with no axial load had a lower strength but higher ductility. It was also found that an increase in the longitudinal reinforcement ratio gave an increase in the failure load while an increase in the transverse reinforcement ratio had no significant effect on the strength but influenced the failure mode. A non-linear finite element program based on the crack membrane model and using smeared-fixed crack approach was developed with a new aggregate interlock model incorporated into the finite element procedure. The finite element model was corroborated by experimental results of shear panels and walls. The finite element analysis of shear wall specimens indicated that while strengths can be predicted reasonably, the stiffness of edge elements has a significant effect on the deformational results for two-dimensional analyses. Therefore, to capture the deformation of walls accurately, three-dimensional finite element analyses are required. The shear wall design provisions given in the current Australian Standard and the Building Code of American Concrete Institute were compared with the experimental results. The comparison showed that the calculated strengths based on the codes are considerably conservative, specially when there exists the axial load.

Wide spaced reinforced masonry (WSRM) walls that contain vertical reinforced cores at horizontal spacing up to 2000mm are commonly used in high wind zones of Australia although their inplane shear resistance is not well understood. This thesis aims at providing better insight into the behaviour of WSRM walls subjected to inplane lateral loading through experimental and numerical investigations. The interactions between the unreinforced masonry (URM) panels and vertical reinforced cores are first determined using an elastic finite element analysis and the potential failure paths hypothesized. The hypotheses are then validated using a series of full-scale WSRM and Non-WSRM wall tests under monotonic and cyclic lateral loading by keeping the spacing between the vertical reinforced cores as the main design variable. Load-displacement response of these shear walls indicates that the current classification of the WSRM in AS3700 (2001) as those walls containing vertical reinforced grouted cores at 2000mm maximum spacing is appropriate. A finite element model (FEM) based on an explicit solution algorithm is developed for predicting the response of the masonry shear walls tested under static loading. The FEM has adopted macroscopic masonry failure criteria and flow rules, damaged plasticity model for grout and tension-only model for reinforcing bars reported in the literature, and predicted crack opening and post-peak load behaviour of the shear walls. By minimising the kinetic energy using appropriate time scaling, the FEM has provided reasonable and efficient prediction of load flow, crack patterns and load–displacement curves of the shear walls. The FEM is further validated using full-scale tests on WSRM walls of aspect ratios and pre-compression different to that tested before. The validated FEM is used to examine the appropriateness of the prescriptive design details for WSRM concrete masonry shear walls provided in AS3700 (2001) allowing for a large scatter in material properties. It is shown that the inplane shear capacity formula provided in AS3700 (2001) for squat WSRM shear walls is non-conservative.

Phosphatidylinositol mannosides (PIMs) isolated from mycobacteria have been identified as an important class of glycolipids that possess significant immune modulating properties. To provide discrete synthetic compounds for biological assay, this thesis describes the syntheses of three PIM molecules, namely dipalmitoyl PIM2 (12), PIM4 (84), and PIM6 (108), and two PIM2 analogues designed for increased stability, PIM2ME (147) and PIM2MA (148). The synthesis of all of these molecules involved mannosylation of 1-O-allyl-3,4,5-tri-O-benzyl-D-myo-inositol (22), which was prepared from methyl α-D-glucopyranoside in 8% yield over 8 steps, using a Ferrier reaction strategy. A common intermediate, 3,4,5-tri-O-benzyl-2,6-di-O-(2,3,4,6-tetra-O-benzyl-α-D-mannopyranosyl)-D-myo-inositol (9), was used for the syntheses of 12, 147, and 148. This compound was prepared by bis-mannosylation of the C-1 and C-6 hydroxyl groups of 22 with 2-O-acetyl-3,4,6-tri-O-benzyl-α-D-mannopyranosyl trichloroacetimidate (63) to give, after protecting group manipulations, the α,α-pseudo-trisaccharide 9 in 37% over 4 steps. The selectivity of the desired α,α-product was found to be increased by the selection of Et₂O as the solvent for the glycosylation reaction. The C-1 hydroxyl group of 9 was coupled to benzyl (1,2-di-O-palmitoyl-sn-glycero)-diisopropylphosphoramidite (28) using 1H-tetrazole. Global debenzylation of the resulting product gave PIM2 (12) in 23% yield over 6 steps from 22. In a similar fashion 9 was coupled to 1-O-hexadeconyl-2-O-hexadecyl-sn-glycero-3-O-benzyl-(N,N-diisopropyl)-phosphoramidite (156), and subsequent deprotection gave PIM2ME (147) in 30% yield over 2 steps from 9. Coupling of 9 with 2-deoxy-1-O-hexadeconyl-2-O-hexadeconylamino-sn-glycero-3-O-benzyl-(N,N-diisopropyl)-phosphoramidite (172) and subsequent deprotection gave PIM2MA (148) in 47% yield over 2 steps from 9. A modified approach was required for the syntheses of PIM4 (84) and PIM6 (108). A selective glycosylation of the C-6 hydroxyl of 22 with an orthogonally protected mannose donor would allow extension of the manno-oligosaccharide in a 2+3 or 4+3 glycosylation strategy required to build the pseudo-pentasaccharide or pseudo-heptasaccharide core of 84 or 108 respectively. Sequential mannosylation of 22, firstly at the more reactive C-6 hydroxyl, with 2-O-acetyl-3,4-di-O-benzyl-6-O-tert-butyldiphenylsilyl-α-D-mannopyranosyl trichloroacetimidate (85), was followed by mannosylation at the C-2 hydroxyl with 63. Removal of the silyl protecting group followed by a 2+3 coupling with the dimannoside donor, 2-O-acetyl-6-O-(2-O-acetyl-3,4,6-tri-O-benzyl-α-D-mannopyranosyl)-3,4-di-O-benzyl-α-D-mannopyranosyl trichloroacetimidate (95), gave a pseudo-pentasaccharide intermediate. Protecting group manipulations followed by coupling of the of the C-1 hydroxyl group of the inositol ring to phosphoramidite 28, and a global debenzylation, gave PIM4 (84) in 6% yield over 9 steps from 22. During the synthesis of PIM6 (108), thioglycosylation chemistry was explored and found to be comparable to reactions with trichloroacetimidate donors. Similar methodology was used for the synthesis of PIM6 (108) as had previously been carried out for the synthesis of PIM4 (84). Mannosylation at the more reactive C-6 hydroxyl of 22 with either phenyl 2-O-benzoyl-3,4-di-O-benzyl-6-O-triisopropylsilyl-1-thio-α-D-mannopyranoside (112) or 2-O-benzoyl-3,4-di-O-benzyl-6-O-triisopropylsilyl-α-D-mannopyranosyl trichloroacetimidate (113), was followed by mannosylation at the C-2 hydroxyl with 63. Removal of the silyl group followed by a 4+3 coupling with either of the tetramannoside donors, phenyl (2-O-benzoyl-3,4,6-tri-O-benzyl-α-D-mannopyranosyl)-(1[to]2)-(3,4,6-tri-O-benzyl-α-D-mannopyranosyl)-(1[to]2)-(3,4,6-tri-O-benzyl-α-D-mannopyranosyl)-(1[to]6)-2-O-benzoyl-3,4-di-O-benzyl-1-thio-α-D-mannopyranoside (109) or (2-O-benzoyl-3,4,6-tri-O-benzyl-α-D-mannopyranosyl)-(1[to]2)- (3,4,6-tri-O-benzyl-α-D-mannopyranosyl)-(1[to]2)-(3,4,6-tri-O-benzyl-α-D-mannopyranosyl-(1[to]6)-2-O-benzoyl-3,4-di-O-benzyl-α-D-marmopyranosyl trichloroacetimidate (131) gave a gave a pseudo-heptasaccharide intermediate. Protecting group manipulations followed by coupling of the of the C-1 hydroxyl group of the inositol ring to phosphoramidite 28, and a global debenzylation, gave PIM6 (108) in 9% yield over 9 steps from 22. To aid characterisation of 108, a sample was deacylated to afford dPIM6 (144) which gave the same spectral data as a sample from a natural source. The compounds PIM2 (12), PIM4 (84), PIM2ME (147), and PIM2MA (148) were assayed for adjuvant activity and were found to have comparable activity to fractions isolated from natural sources. The analogue PIM2ME (147) gave the best results and is currently undergoing further development.

Includes bibliographical references (p. 217-227).

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 357-378).

Thesis--M. Sc.(Eng.), University of Hong Kong. / Mimeographed.

Thesis (M. Phil.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 181-186).