Method for Inferring the Design Value of the Resistance Based on Probabilistic Model

Methods for inferring the design value of the resistance based on test have long been studied extensively, but the existing methods have several limitations on unified guarantee rate ensurance and reliability control. Firstly, the rationales and deficiencies of the present methods in ISO 2394 : 2015 and EN 1990 : 2002 were generalized. Secondly, in view of the disadvantages, a new inferring method combining the probability model of resistance with statistical approach was put forward. The proposed method established a relationship among design resistance, probability characteristics of known factors, and statistical results of unknown factors and possessed a rigorous and sound theoretical basis on both conditions that the coefficient of variation of model uncertainty was unknown and full known. Lastly, a contrast work was carried out between the Eurocode method and the proposed method; the results showed that the latter method had a higher inferring value, which means a better inferring result.

Influence Of New Design Characteristics Of Wood On Determining The Longitudinal Bending Coefficient

The standard methodology for calculating the stability of wooden rods, in which the longitudinal bending coefficient depends on the ratio of the elastic modulus to the design resistance is implemented in a linear formulation. The use of this linear method for calculating wooden structures that have a creep in time is due to studies conducted in the last century, in which it was found that this ratio for wood is constant, both during short-term loading and long-term loading. Since then, this characteristic for wood, used in calculations for the design of wooden structures, has not changed practically and the method of calculating the stability has not lost its relevance. But in the latest version of the design standards for wooden structures, the design resistances and elastic modulus for lumber, glued wood and new material made of unidirectional veneer differ depending on the strength classes, and the ratio of the elastic modulus to the design resistance becomes variable. Therefore, the formula for calculating the longitudinal bending coefficient for wooden rods with a flexibility of more than 70, left unchanged in the latest version of the norms, requires adjustment. It is proposed to change this formula taking into account the new values of the calculated strength and deformation characteristics for solid and glued wood elements. At the same time, the method of assigning calculated values of the modulus of wood elasticity is being questioned.

COMPARATIVE STUDY ON ANALYSIS OF TELECOM TOWER USING INDIA AND AMERICAN STANDARDS

Self-supporting lattice tower are being effective structural system by considering simple, light weight, easy fabrication and installation for supporting telecom equipment at elevated heights. With increase in demand of lattice towers, a critical review on approach for analysis is highly essential to ensure reliable and safe structures. In this paper, a comparative study is taken up on methodologies followed in both national standards (India, America) for assessment of wind loads on bare tower, linear accessories, discrete accessories along with design resistance of members and connections for Two different configurations – Square angular tower, Triangular Hybrid Tower. From the detailed analysis, it is concluded that, American standard (ANSI/TIA-222H) is using Ultimate windspeed for calculation of wind loads based on risk category of structure along with strength reduction factors based on criticality of components compared to Indian Standards (IS 875(Part 3)-2015, IS 802) which resulted lesser wind load on structure i.e., 30% in Square Tower (Oblique wind direction) and 23% in Triangular Hybrid Tower using ANSI/TIA-222H. Also, no major difference observed for calculation of member capacity and connection. Therefore, it is concluded that Tower weights approximately reduces by 10-15% based on Tower configuration using ANSI/TIA-222H compared to Indian Standards

Optimization of the formulaof the design resistance of soil

The assumptions made in the derivation of the formula for the design soil resistance are considered. It is shown that in the conditions of the plane problem, taking into account the coefficient of lateral soil pressure leads to lower values of the initial critical load and, consequently, to a decrease in the design resistance. The equation of limiting equilibrium is implemented in the MathCad software package, which makes it possible to obtain isolines of deviation angles at any depth from the applied uniformly distributed load. To determine the initial critical load, a formula is given that takes into account the coefficient of lateral soil pressure K0. In the final part of the article, the solution to the problem is given according to the formula of N. P. Puzyrevsky and according to the formula derived by the author, taking into account K0, the difference in the isolines of the deflection angles is presented, and an analysis of a similar problem in the Plaxis 2D software package is carried out.

Elaboración de bloques de construcción a partir de residuos de arena sílica proveniente del proceso de fundición aluminio en una empresa automotriz

The objective of the project was to develop a procedure for the construction of building blocks with silica sand residues, from an aluminum smelting process of an automotive spinning company. The blocks obtained were evaluated in accordance with NMX-C-404-1997-ONNCCE standards for the design and formulations of the block, and NMX-C-036-ONNCCE for tests and compression calculations. Initially these arenas are used for the elaboration of the molds of the mechanical parts that are manufactured in the company, however, once the utility of these arenas for molding is fulfilled, they are sent to final disposal sites. For the elaboration of the blocks, the physical characteristics and chemical properties of the silica sand were initially determined (grain size, pH, structure, grain shape, humidity, specific gravity, bulk and bulk density). The mold was then designed and two formulations based on the residues of silica sand, cement, water and lime were tested. The product quality assessment included tests for drying, moisture absorption, design resistance to compression. Finally, the manufacturing costs were compared with the costs of existing commercial blocks in the market.

Structural Reinforcement of a Masonry Building

A structural reinforcement carried out on a 12th century mansion in masonry with the aim of a seismic improvement valued as a decrease in the Seismic Risk Class [4].The reinforcement technique combines the use of FRP systems with carbon fiber strips applied to the external perimeter walls and FRCM systems applied to the internal walls.The proposed solution allows the seismic improvement both in relation to local failure phenomena and in the overall behavior of the whole structure. Particular focus is given to the dimensional calculation of the reinforcements and to the combined contribution of the two techniques, highlighting the peculiarities of both. The FRP system is used to avoid overturning and to increase the resistance of the walls, while the FRCM system is used for the general improvement of the mechanical properties of the masonry. Particular attention is paid to the evaluation of the design resistance values related to the debonding failure by carrying on special technical measures in installation of aramid fiber or CFRP connectors.The intervention methodology allows an increase of the Seismic Risk Class of at least 3 levels, as deductible from the calculation of the PAM value.