The free vibration characteristics, such as fundamental frequency and mode shape of stiffened plates employing standard finite element analysis, are investigated in this paper. The parametric study is presented for free vibration characteristics of stiffened plates with various parameters, such as type, orientation and number of stiffeners, boundary conditions and aspect ratio of plates and stiffener depth to plate thickness ratio. Typical mode shapes are also presented for clamped square eccentrically stiffened plates. Finally, design charts with non-dimensional parameters are proposed to determine the fundamental frequency of commonly adopted clamped stiffened plates in construction. These charts will be very much useful for designers for obtaining the fundamental frequencies of the stiffened plates of different dimensions without doing much complicated analysis or using standard computer codes.

A large part of the global brick manufacturing industry has evolved based on knowledge transmitted from generation to generation without developing a consistent scientific approach. The purpose of this article is to contribute to this approach by discussing the state-of-the-art and future trends of the design and construction of artisan brick kilns (ABK). The methodology proposed for this study is based on a systematic literature review whereby main question is: What research exists on brick kilns? Based on the results of this review, it is recommended that appropriate emerging technologies that should be incorporated to ABKs for either medium or small enterprises should be: mechanical fans, envelope thermal insulation, organic waste of uniform size as fuel, automatic control of process variables and computer simulations of phenomenological processes. This should be accompanied by technical training for the brick-makers and greater access to financing funds. The technologies reviewed throughout the paper will allow for a more thermally efficient design of kilns, which will emit less hazardous greenhouse gases and atmospheric pollutants.

Tires are an industrial waste that has become a worldwide environmental problem. To minimize this effect, tire waste is used in construction as a concrete aggregate. Additionally, carbon dioxide in the atmosphere affects the carbonation of concrete. This study analyzes the effect of carbonation in concrete with tire rubber aggregate as a 0%, 10%, 20%, 30%, 40%, 50% and 60% proportional replacement for the fine aggregate. The carbonation test was conducted for 2, 4, 6 and 24 hours. The compressive strength of the concrete decreased depending on the tire rubber content in the mixes, while the concretes with tire rubber percentages greater than 30% were affected by carbonation.

The pulp industry generates large amounts of wood biomass ash (WBA) as waste, which causes economic and environmental problems. However, WBA has pozzolanic and cementing properties that can complement cement in concrete production. Many studies have been published on the replacement of cement by WBA, but few discuss the replacement of other concrete components such as sand. The objective of this research is to determine the effect of volume replacement of sand with ash on the mechanical resistance of concrete. A reference concrete was made with a specified strength of 30 MPa at 28 days. Samples with 5%, 10%, 13%, 15% and 20% WBA were compared. A water-cement ratio of 0.49 was maintained, plasticizer was added to maintain an acceptable workability, and compression tests were conducted at 7, 28 and 63 days. The results indicate that WBA decreases the workability of the fresh concrete mixture. However, the compressive strength increases in most cases, thus demonstrating the possibility of using WBA as an addition to the concrete to improve its mechanical properties, and at the same time reduce the environmental impact of this waste material.

The relationship between various steel strip geometries and the bonding energy through pull-out tests of aerated concrete specimens is investigated. Prismatic concrete samples containing embedded steel strips with and without holes of differing sizes and quantities were analysed. Improvements of the bonding energy through pull-out tests by 70% are possible by increasing the number of holes on a steel strip from one to four while maintaining a constant surface area. The energy increased even up to 130% for strips containing holes compared to strips without. In addition, the tests have been carried out with a novel easy to assemble set-up containing a freely adjustable ball-joint and a plate with embedded bolts to avoid eccentricity during pull-out tests.