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In this article, the problem peak-to-peak gain control (also known as [Formula: see text]-gain control) via static output-feedback scheme is studied for discrete-time positive linear systems with diverse interval delays. By novel comparison techniques involving steady states of upper- and lower-scaled systems with peak values of exogenous disturbances, a characterization for [Formula: see text]-induced norm of the input–output operator is formulated. The obtained characterization is then utilized to derive necessary and sufficient conditions subject to [Formula: see text]-induced performance with prescribed attenuation level. On the basis of the analysis results, and based on a vertex optimization technique, a complete solution to the synthesis problem of a static output-feedback controller that minimizes the worst case amplification from disturbances to regulated outputs subject to peak-to-peak gain is addressed. The derived stabilization conditions are formulated in terms of tractable linear programming conditions, which can be effectively solved by various convex algorithms. Numerical examples and simulations are given to illustrate the effectiveness of the proposed method.

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The damage of reinforced concrete columns due to shear is often serious, so this type of failure should be avoided from the design. In this paper, a model derived based on the discrete computational method is proposed to calculate the shear strength of column carried by multi-spiral transverse reinforcement, accounting for the effect of compression depth. Furthermore, based on this model, a method is proposed to predict the failure mode of multi-spiral columns. The test database of multi-spiral columns from previous studies is used to validate both the shear strength and failure mode predictions. The proposed model with a crack angle of 40 degrees gives the best estimation of the shear strength of multi-spiral columns, and the proposed method predicts well the failure mode of these columns. To avoid shear failure, the ratio of the minimum shear strength calculated from the proposed model with a crack angle of 40 degrees to the shear force based on the moment-curvature analysis is suggested to be larger than 1.2.

Due to rapid industrialization and modernization, a large number of both fly ash (FA) and ground granulated blast furnace slag (GGBFS), both by-products from thermal power plants and steel factories, are increasing day by day. Thus, recycling these industrial wastes to produce lightweight foamed concrete (LFC) was investigated in this study. Eight LFC mixtures were designed with different FA content and foam content to investigate their effect on the properties of LFC. Test results indicate that both FA and foam contents had a significant influence on the properties of LFC. The quality of LFC decreased with increasing foam content while the presence of FA improved its properties. The properties of LFC and its dry unit weight had a close relationship, and the correlation between them was described by linear regression. For example, high foam content resulted in more void volumes inside the LFC thus reducing its properties. Meanwhile, the presence of FA minimized the void volume and enhanced the LFC’s properties. All LFCs in this investigation showed good quality, which were classified as grade M3.5-12.5 based on TCVN 9029:2017, which means they can be used as unburnt bricks with significantly low unit weight and thermal conductivity.