Reinforcement of wood with natural fibers

This paper describes an experimental programme which examines the reinforcement in flexure of timber beams with composite materials based on natural fibers in the form of fabrics made from hemp, flax, basalt and bamboo fibers. The industrial use of natural fibers has been continuously increasing since 1990s due to their advantages in terms of production costs, pollution emissions and energy consumption for production and disposal. The technique allows the reinforcement of the intrados of beams, avoiding the dismantling of the overlying part of the structure with significant savings in terms of costs and work time. The test program consists of three phases incorporating 45 beams. The bending tests on the wooden elements made it possible to measure the increase in capacity and stiffness resulting from the composite reinforcement. This was applied to beams, creating different arrangements and using different quantities (number of layers). Despite the diversity of the various tests carried out, the results obtained in some cases showed significant increases in terms of load-carrying capacity and in deflection ductility

Shear strengthening of masonry panels using a gfrp-reinforced mortar coating

The use of new composite materials for reinforcement of heritage masonry structures, especially in seismic prone areas, is of interest structural engineers and conservators. However, the need to increase the structural performance of masonry structures is often in contrast with the principles of conservation in terms of reversibility, limited visual impact, compatibility of new materials with masonry. With the aim at striking a balance between structural safety and heritage protection, this paper investigates strengthening stone and brickwork masonry walls using glass-fiber reinforced polymer (GFRP) meshes embedded into a coating of lime or cement mortar. An experimental research program was undertaken in the laboratory on large-scale wall panels. Both clay brick and stone work specimens were tested, with and without strengthening. Single-sided and double-sided strengthenings were considered, as it is often not practicable to apply the reinforcement to both sides of a wall. Static tests were carried out on twelve masonry panels, under in-plane diagonal shear loading. The mechanisms by which load was carried were observed, varying from the initial, uncracked state, to the final, fully cracked state. The results demonstrate that a significant increase of the in-plane shear capacity of masonry can be achieved by using the proposed retrofitting technique. The experimental data were used to assess the effectiveness of the strengthening, and a finite element (FE) numerical model is discussed and calibrated against experimental results. The FE model was used to investigate further aspects of the reinforced masonry under shear-loading

Determinant Factors of Dividend Payments in Brazil

This study identifies factors that shaped cash disbursement distribution policies employed by Brazilian public companies listed on the Brazilian Securities, Commodities and Futures Exchange (BM&FBOVESPA) from 1995 to 2011. Relationships between Dividends/Total Assets and potential determinants discussed in the literature, including firm size, corporate governance, profitability, leverage, market to book, liquidity, investment, risk, profit growth, information asymmetry and agency conflict, are examined. The following econometric methods are employed: (1) Tobit, given the nature of the dividend data, and (2) the Generalized Method of Moments (GMM) to control for endogenous regressors. Significant positive variables found include size, return on assets (ROA), market to book, liquidity and profit growth. It can thus be inferred that larger firm size, profitability, market value, liquidity and profit growth correlate with greater firm pro pensity to distribute money to shareholders, thus supporting the theory of corporate finance. Significant negative variables found include leverage, liquidity squared, capex, beta and tag along 100%. It is thus inferred that more significantly leveraged companies that invest more heavily in fixed assets and that exhibit high liquidity, higher risk and less conflict between controlling and minority shareholders will be less likely to pay dividends to shareholders.</p