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Compression behaviour of structural clay block prisms with different shell and web thickness
Published in Claudio Modena, F. da Porto, M.R. Valluzzi, Brick and Block Masonry, 2016
C.Z. Valdameri, L.F. Coelho, K.M. Junior, M. Utzig, H.R. Roman
ABSTRACT: The Brazilian clay block industry increases every year in both, amount of fabricated products and production technology. The Brazilian standard for structural clay blocks specifies that the shell faces and webs of hollow ceramic blocks must have a minimum thickness of 8 mm and 7 mm respectively. The brickyards have experimentally produced structural blocks with thinner shell and webs thickness to study their structural behaviour in order to help future discussions about the specifications of the standard code. This works presents experimental results of compression tests with 3 courses clay block prisms of same geometry but different web and flanges thicknesses. Two different mortar mixes were used: 1:1:6 and 1:0,5:4,5 (cement:lime:sand) by volume. The blocks physical and mechanical properties tested were: compressive strength, dimensions, net area and water absorption. The mortars were tested on compressive strength and flexural tensile strength. The prism test results were statistically evaluated using factorial analysis and have shown that both the mortar and the block wall thickness significantly influence the prism compressive strength. Prisms made with thicker block webs and flanges have presented higher compressive strength regardless of the mortar type used. On the other hand, if the net area is considered, the block strength/prism strength relationship is the same independently of the web and shell face block thicknesses.
Determination of Ritter constant for hollow clay prisms under compression
Published in Jan Kubica, Arkadiusz Kwiecień, Łukasz Bednarz, Brick and Block Masonry - From Historical to Sustainable Masonry, 2020
G. Mohamad, F.S. Fonseca, H.R. Roman, T. Ottoni, A. Lubeck
The tests were conducted to evaluate the stress/strength and strain behavior of the blocks under compression until failure. For measurements, ten strain-gauges on both surfaces were used. For each block type, five samples were prepared and tested. The results indicate that the ultimate axial strain at failure varies from 2 to 2.5‰, as presented in Figure 5. The most interesting fact was the linear behavior for both hollow and solid face shell blocks. Also, a very abrupt and brittle failure was observed for blocks SFS. A linear trend line was fitted to the experimental data to determine the correlation between stress/strength and strain measurement of the blocks until failure.
Effect of negative phase of pulse loading on response of machine foundations vibrating under harmonic loads
Published in Mechanics Based Design of Structures and Machines, 2022
Kirtika Samanta, Priti Maheshwari
The analysis and design of foundations accommodating gas engines, stamping machines, and rotary compressors, subjected to static loading due to the weight of the machine and the foundation block, and dynamic loading due to the machine vibrating under its operating condition, are somewhat complex. Block type foundations are generally used for supporting gas engines, compressors, and forging hammers. Over the years, several research workers such as Gazetas (1983), Mironowicz and Śniady (1987), Nayfeh and Serhan (1989), Aşik (1999), Chehab and El Naggar (2004), Chen and Shi (2006), Chen, Liao, and Shi (2016), Adhikari and Singh (2019), and Uzun, Civalek, and Ö Yayli (2020) have analyzed the dynamic behavior of foundations. Main aim in designing these foundations is to limit their amplitudes within permissible limits.
Integrated production quality and condition-based maintenance optimisation for a stochastically deteriorating manufacturing system
Published in International Journal of Production Research, 2019
Abdelhakim Khatab, Claver Diallo, El-Houssaine Aghezzaf, Uday Venkatadri
To overcome the above-mentioned drawbacks of the joint PM and SPC approaches, Chen and Jin (2006) considered a quality-oriented-maintenance problem for tooling components in a discrete manufacturing process. In their approach, product quality deteriorates with the degradation of the tooling components. To improve the product quality, preventive replacements are carried out on tooling components. A quality-oriented-maintenance optimisation model is proposed while considering the joint and interactive impacts of multiple adjustable process variables on product quality. The optimisation model is formulated as a response model and determines the optimal replacement times for tooling components by minimising the total production cost composed of product quality loss due to process drifts, productivity loss due to catastrophic failures, in addition to maintenance costs. The work by Chen and Jin (2006) has been extended in Ji-wen et al. (2010) by considering catastrophic failures due to random shocks and the obsolescence cost in a multi-station machining system. Three maintenance policies, namely, age replacement, block replacement, and block replacement with minimal repair, are then investigated and analysed.
Numerical simulation tool for paving block structures assessed by means of full-scale accelerated pavement tests
Published in International Journal of Pavement Engineering, 2018
J. Füssl, H. Hengl, L. Eberhardsteiner, W. Kluger-Eigl, R. Blab
During testing the main problem was the rapid loss of jointing sand, since the sand joints within the newly constructed slab test sections had no time to consolidate and to develop conventional inter-locking status. Therefore, it was necessary to add jointing sand during the maintenance stops of the MLS10. However, inspection and refilling of joints are regular maintenance actions for paving block structures during their lifetime. For further tests on these types of pavements it is, thus, recommended that new test sections are exposed to environmental conditions (rain, dust) for a few weeks before the start of the APT until the jointing material consolidates. Nevertheless, it can be stated that the execution of the APT and the projected load applications were completed successfully (see Table 2).