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The aim of this paper is to present preliminary results regarding Engineered Cementitious Composites (ECC) and their behaviorwhen experimentally assessing their fracture energy, bymeasuring the flexural tensile strength (limit of proportionality, residual). As a characteristic of a ductile material, fracture energy is an important parameter when assessing ECC post-cracking residual stresses. With 2% fibers addition in the mixtures, the crack width can be controlled and the material's ability to bear a tensile strain-hardening capacity has been assessed. Ninety days flexural tensile strength tests were performed in order to obtain preliminary results on ECC prismatic specimens. [ABSTRACT FROM AUTHOR]

This paper is of design of an automated millet milling machine that targets the small-scale manufacturing. The demand of millet is high in the lowveld region in Zimbabwe and other arid to sub-arid regions in Asia. About 8 million tonnes of millet is produced in India per annum, accumulating to 40% of pearl millet's global production. The existing problem is that millet's demand is increasing due to health and food security reasons yet milling passes through many laborious stages and millet milling machines are relatively expensive to small scale manufacturers in developing countries. Data was collected from published scholarly documents, internet, experts in the field and local companies in the food processing industry. Extreme wearing of the rods with the hammers, development of cracks in neighbourhood of the holes contacting the rods to the hammers, with the likelihood of breakaway fracture and catastrophic results. Also, rolling contact bearings give difficult problems of balance uneven mass distribution and resonance. Numerous analysis of existing machine, use of local cheaper materials and combined mechanisms it was possible to produce a low cost and efficient product. The hammers hit the grains and shatter them before they can pass through the 0.5 mm hole screen surrounding the hammers. Hammer mill size reduction uses impact as the grain hits the projecting hammers, the screen material, and the mill cast iron casing. If this design is implemented, there will be positive benefits through supporting small manufacturing enterprises (SMEs) as stated in the Sustainable Socio-Economic Transformation agenda of Zim-ASSET. [ABSTRACT FROM AUTHOR]

A number of structures in the Czech Republic were affected by flooding in August 2002. In particular, damage to structures adjacent to the Vltava River in Prague was on an unprecedented scale. This paper reports on a forensic investigation to assess whether the flooding was exceptional and to identify the main causes of structural failure. The work included statistical analysis of hydrological data dating back to 1827, from which it was shown the 2002 event had a considerably long return period. However, the investigation also revealed that lack of structural robustness may have contributed to disproportionate failure. [ABSTRACT FROM AUTHOR]

This paper proposes a new method for visualizing the earth fissures of geological structure in three dimensional (3-D) domains on the basis of the seismic data and features information of earth fissures. The seismic data were interpreted for obtaining the stratagraphic data with various lithological information and the depth of the earth fissures. The spatial distribution of the ground fissures including the dip, strike and width were digitalized on an ArcGIS platform. Firstly, the 3-D geological structure was rebuilt using the Generalized Tri-Prism (GTP) method which is a real solid method for displaying geological structures. The GTP method can reflect the inner material of the strata and can simulate complicated geological structures such as faults and stratagraphic pinch outs. The upper and lower surfaces of each stratum consist of Triangle Irregular Networks (TIN). The inner solid between the two surfaces are a series of triangular prisms. Secondly, since the width of the ground fissure gradually decreases with depth, multiple edge lines of the earth fissures on the bottom stratum surface are deduced on the basis of the fissure characteristics. Then, the model of the earth fissures consisting of a series of triangular pyramids can be constructed using these points and the edge lines. A cutting operation was carried out on the 3-D geological structure using this ground fissures model. If the surfaces of the ground fissures model intersects with the GTPs in the geological structure model, new GTPs were generated within the local regions. During this process, the topological relations between TIN, triangular prism and lines were reconstructed so that the visualization of ground fissures in the geological structure model is realized. This method can facilitate the mechanism for studying fissures and avoid the gaps between the fissure solid and the geological structure to accurately reflect their 3-D characteristics. [ABSTRACT FROM AUTHOR]

A crack in the vibrant structures can lead to premature failure if it is not identified in early stages. The failure rate increases as the crack growth increases due to the structure becomes weaker. Therefore, crack identification and type of crack is a key issue. The existence of cracks which influence the performance of structure as well as the vibration parameters such as; natural frequencies, mode shapes, stiffness and modal damping. Our current investigation is to model an inclined open edge crack in a cantilever beam and analyze the model using a finite element package, as well as experimental approach. A finite element model has been developed in this paper to analyze the variation of modal parameters according to the location, size and inclination of a crack in the cantilever beam having inclined edge crack. The proposed method is based on measured frequencies and mode shapes of the beam. The experiments are also carried out using specimens having inclined edge cracks of different depths, positions and crack inclinations to validate the FEA results achieved. [ABSTRACT FROM AUTHOR]

The paper analyzes research on the formula proposed by Bazant, where the existence of size effect is shown. The beams made of different types of concrete loaded at three points, with a slot in the middle of the beam, were experimentally burdened to the point of fracture. The fracture energy (Gf) and the characteristic length in the fracture zone (cf) were determined. For the experiment beams of common, high-quality, lightweight concrete and concrete with steel fibers were used. As the fifth sample ordinary concrete with a change in the width of the bearing under load was made. The maximum size of aggregate grain for the concrete is 10 mm. The beams for the experiment were of three different sizes, and three samples of each size. A total of 45 beams were used. Cross-section of beams was changed proportionally. [ABSTRACT FROM AUTHOR]

When designing structures to Serviceability Limit State it is essential to prove the cracks are within the ultimate values. Cracks do not always hinder a structure if their widths do not exceed the prescribed limit values usually conditioned by corrosion, impermeability to liquids or gasses, or by appearance of the structure. Procedures given in various codes such as [ENV 1992-1-1:dec. 1991], [BS EN1992-1-1:2004] as well as [DIN 1045-1]), for determination of crack widths and only for members subject to pure bending are considered in this paper work. Calculation of crack width in RC member is presented through examples and for short term (t = 0) and long term (t = ∞) loading, according to ENV 1992-1-1 and BS EN 1992-1-1:2004, while limiting of crack width without direct calculations is done based on the provisions within ENV 1992-1-1:2004, BS EN 1992-1-1:2004 and DIN 1045-1. [ABSTRACT FROM AUTHOR]

This paper analyses the fracture behavior of the brazed BCBN grain by comparison with brazed PCBN grain through grinding test of Nickel-based superalloy. The self-sharpening effect is created by timing micro-fracture behavior for BCBN abrasive grains, but by macro-fracture behavior for PCBN abrasive grains. During grinding with brazed BCBN abrasive grains, the material is removed together with the consumption of the CBN particle. While for PCBN ones, the fracture pattern consists of the intercrystalline fracture and the intergranular bond fracture. The service life of brazed BCBN grinding tool is around 1.67 times longer than that of PCBN one, furthermore the material removal of PCBN grinding tool is just about 73% of that of BCBN grinding tool in this investigation. [ABSTRACT FROM AUTHOR]

Structural failures during construction or in service nearly all result in claims and litigation, the outcome of which is strongly influenced by forensic investigations. Identifying causes of failure and the party responsible, plus technical presentation of subsequent claims and defences, generally requires all parties to engage forensic engineers as witnesses. This paper is an overview of the highly active professional practice of forensic structural engineering in the USA, possibly the world's most litigious environment for construction. It discusses the origins and causes of failures, the process of forensic investigation, the role of expert witnesses and a list of further reading. [ABSTRACT FROM AUTHOR]

Concrete is the most used material in the construction industry, being prone to cracking. Following the action of aggressive external agents, through cracks, access routes to the embedded reinforcement are created. By enclosing in concrete various materials that can induce the self-healing property, by taking actions when the cracks appear, the access of the external aggressive agents to the reinforcement can be stopped, therefore creating more durable materials. The aim of the research is to design a micro concrete with self-healing properties, based on Engineered Cementitious Composites principles from the literature and using local raw materials. [ABSTRACT FROM AUTHOR]

Continuous measurements of deformation have been made in Chino, California across an earth fissure and nearby unfissured soil since 2011 in two buried, horizontal, 150mm pipes, 51m long, which are connected by sealed boxes enclosing vertical posts at mostly 6m intervals. Horizontal displacements and normal strain are measured in one line using nine end-to-end quartz tubes that are attached to posts and span fissured or unfissured soil. The free ends of the tubes are supported by slings and move relative to the attachment post of the next quartz tube. Linear variable differential transformer (LVDT) sensors measure the relative movements. Five biaxial tilt sensors were also attached to selected posts in that line. Relative vertical movement was measured at nine locations along the line in the second pipe using low-level differential pressure sensors. The second pipe is half full of water giving a free water surface along its length. Data are recorded on a Campbell CR10 using multiplexers. The quartz-tube horizontal extensometers have exhibited more than 3mm of predominantly elastic opening and closing in response to about 32m of seasonal drawdown and recovery, respectively, in an observation well 0.8 km to the south. The nearest production well is 1.6 km to the west. The horizontal strain was 5:9×10-5 or 30% of the lowest estimate of strain-at-failure for alluvium. Maximum relative vertical movement was 4.8 mm. Maximum tilt in the fissure zone was 0.09 arcdeg while tilt at a separate sensor 100m to the east was 0.86 arcdeg, indicating a wider zone of deformation than is spanned by the instrumentation. High correlation of horizontal displacements during drawdown, and especially recovery, with change in effective stress supports differential compaction as the mechanism for earth-fissure movement. The continuous measurements of horizontal strain coupled with water-level fluctuations and vertical borehole extensometry can provide a real-time adaptive management tool for restricting pumping if strain approaches the lower limit of strain-at-failure or a stress-strain curve deviates from the previous mostly elastic regimen. [ABSTRACT FROM AUTHOR]

The Gaoliying ground fissure in Beijing has caused building cracking and road damage, and has seriously influenced city construction. Based on investigations and trenching, the influences of the fault and the variation of groundwater levels on the formation mechanism of the Gaoliying ground fissure were investigated by using FLAC3D. The results indicated that (1) the surface location of Gaoliying fissure is controlled by the underlying normal fault activity, and over pumping further exacerbates development of the ground fissure; (2) when the groundwater level declines, obvious differential settlement occurs at both sides of the ground fissure, in which greater settlement occurs in the vicinity of the hanging wall, the greater the distance from the hanging wall, the smaller the ground subsidence, however smaller ground subsidence occurs in the vicinity of the footwall, the greater the distance from the footwall, the greater the ground subsidence; (3) the vertical velocity of the ground fissure triggered by the fault activity and groundwater decline ranges from 15.5 to 18.3mma-1, which is basically in line with the monitoring data. The fault activity contributes about 28-39 %, and the groundwater contributes about 61-72% to the deformation of the ground fissure, respectively. [ABSTRACT FROM AUTHOR]