Wyniki wyszukiwania - BazTech

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Prawidłowość wykonywania wycięć w strunobetonowych płytach kanałowych oraz konsekwencje błędów w tym zakresie i sposoby naprawy

Błaszczyński Tomasz Z., Gwozdowski Błażej, Sinacki Dawid

Builder

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2020

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R.24, nr 9

36--40

PL

Stosowanie prefabrykowanych płyt strunobetonowych stało się tak powszechne, że zajmują się nimi już wszyscy, uważając te elementy za nieskomplikowane. Dotyczy to również wykonawstwa oraz modernizacji już zrealizowanych obiektów budowlanych. Pomimo szczegółowych wytycznych producentów i projektantów tego rodzaju płyt problemem wciąż jest zbyt duża dowolność w ich wycinaniu i wykonywaniu otworów, zwłaszcza na etapie realizacji lub zmian sposobu użytkowania w trakcie istnienia obiektów budowlanych. W pracy przedstawiono ogólne zasady bezpiecznego wycinania i otworowania prefabrykowanych płyt strunobetonowych oraz przypadki błędów popełnionych przy projektowaniu i realizacji stropów płytowych, prowadzące do stanów awaryjnych.

EN

The usage of prefabricated prestressed hollow-core slabs has become so widespread that everyone is already considering these elements as simple. This also concerns the execution and modernization of already realized buildings. Despite the detailed guidelines for designers of this type of slabs, still is a problem with incorrectly make cut-offs and holes, especially at the stage of implementation or changes in the way of use during the existence of buildings. The paper presents general principles for safe cutting and opening of prefabricated prestressed hollow-core slabs and cases of errors made in the design and implementation of slab floors, leading to emergency conditions.

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Mode frequency analysis of antisymmetric angle-ply laminated composite stiffened hypar shell with cutout

Chaudhuri Puja Basu, Mitra Anirban, Sahoo Sarmila

Mechanics and Mechanical Engineering

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2019

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Vol. 23, nr 1

162--171

EN

This article deals with finite element method for the analysis of antisymmetric angle-ply laminated composite hypar shells (hyperbolic paraboloid bounded by straight edges) that applies an eight-noded isoparametric shell element and a three-noded beam element to study the mode-frequency analysis of stiffened shell with cutout. Two-, 4-, and 10-layered antisymmetric angle-ply laminations with different lamination angles are considered. Among these, 10-layer antisymmetric angle-ply shells are considered for elaborate study. The shells have different boundary conditions along its four edges. The formulation is based on the first-order shear deformation theory. The reduced method of eigen value solution is chosen for the undamped free vibration analysis. The first five modes of natural frequency are presented. The numerical studies are conducted to determine the effects of width-to-thickness ratio (b/h), degree of orthotropy (E11/E22), and fiber orientation angle (θ) on the nondimensional natural frequency. The results reveal that free vibration behavior mainly depends on the number of boundary constraints rather than other parametric variations such as change in fiber orientation angle and increase in degree of orthotropy and widthto-thickness ratio.

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Analytical and Experimental Studies of Stability of Cylindrical Shells with a Cut-Out

Stasiewicz P.

Mechanics and Mechanical Engineering

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2013

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Vol. 17, nr 2

167--176

EN

Thin-walled structure, by its nature, is subjected to loss of stability. In addition, the shell has a cutout, which reduces the critical load. The aim of this study is to determine critical stress of the shell under pure bending. The goal was achieved in two ways: experimentally and analytically. Experimental studies were carried out on a specially designed test bench with the use of a resistive strain gauge. In the analytical solution the form of buckled shell was assumed, and then Bubnov-Galerkin method was applied.