Dynamic Responses of Blast-Loaded Shallow Buried Concrete Arches Strengthened with BFRP Bars

This paper proposes a prefabricated basalt fiber reinforced polymer (BFRP) bars reinforcement of a concrete arch structure with superior performance in the field of protection engineering. To study the anti-blast performance of the shallow-buried BFRP bars concrete arch (BBCA), a multi-parameter comparative analysis was conducted employing the LS-DYNA numerical method, which was verified by the results of the field explosion experiments. By analyzing the pressure, displacement, acceleration of the arch, and the strain of the BFRP bars, the dynamic response of the arch was obtained. This study showed that BFRP bars could significantly optimize the dynamic responses of blast-loaded concrete arches. The damage of exploded BBCA was divided into five levels: no damage, slight damage, obvious damage, severe damage, and collapse. BFRP bars could effectively mitigate the degree of damage of shallow-buried underground protective arch structures under the explosive loads. According to the research results, it was feasible for BFRP bars to be used in the construction of shallow buried concrete protective arch structures, especially in the coastal environments.

STRUCTURAL SOLUTIONS FOR STRENGTHENING DAMAGED STONE ARCH STRUCTURES

Рассмотрены исторические аспекты возникновения каменных арочных конструкций перекрытий, материалы, которые использовались для их возведения в различные исторические периоды, классификация арочных конструкций, а также основные конструктивные решения и технологические аспекты их возведения. Приведены результаты работ, выполненных по определению численных значений геометрических параметров и обследованию технического состояния арочных конструкций зданий старой постройки, расположенных в центральной (исторической) части г. Казани. Приведены результаты исследования работ других авторов по определению наиболее часто встречающихся дефектов и повреждений в арках, а также причины их возникновения. Рассмотрены технические решения различных авторов по усилению арочных конструкций, с использованием различных материалов, в том числе и композитными материалами на основе однонаправленных углеродных волокон. Описана область применения и изложены технические решения, разработанные авторами статьи для усиления арочных конструкций, которые учитывают особенности их конструктивных решений и повреждений. We considered the historical aspects of the emergence of stone arched structures of ceilings, the materials used for their construction in various historical periods, the classification of arched structures, as well as the main design solutions and technological aspects of their construction. We present the results of the work performed to determine the numerical values of geometric parameters and to survey the technical condition of arched structures of old buildings located in the central (historical) part of Kazan. As well we demonstrate the results of a study of the works of other authors to determine the most common defects and damages in arches and the causes of their occurrence. We show the technical solutions of various authors to strengthen arched structures using various materials, including composite materials based on unidirectional carbon fibers. We describe the scope of application and outline the technical solutions developed by the authors of the article for strengthening arched structures that take into account the features of their design solutions and damages.

PENGGUNAAN SISTEM STRUKTUR RANGKA ATAP TIPE PELENGKUNG 3 SENDI

So far, the system of the roof structure of residential and office buildings is dominated by conventional frame types. The use of a 3-joint arch structure system is only familiar to warehouse buildings and the like. The purpose of this study is to identify the feasibility of using type 3 joint arches on the roof of a residential building. The research scenario is focused on calculations using SNI 7973-2013, namely Design Specifications for Wooden Construction and Specific Static Structural Analysis Methods for 3 Joint Arch Structures based on the length of the truss span model, which is 9 m. The calculation result indicates that 1). The 3-joint curve type is worth using as it proves stable and safe 2). The distance between the truss of the roof truss affects the dimensions of the truss. The implication is that the construction of the roof of a residential house can use a 3-joint arch structure system while the basic material for modeling uses Code E20 wood material with Quality B, depending on the length of the span and the slope of the roof.

Evaluating the Seismic Capacity of Dry-Joint Masonry Arch Structures via the Combined Finite-Discrete Element Method

The behaviour of dry-joint masonry arch structures is highly nonlinear and discontinuous since they are composed of individual discrete blocks. These structures are vulnerable to seismic excitations. It is difficult for traditional methods like the standard finite element method (FEM) to simulate masonry failure due to their intrinsic limitations. An advanced computational approach, i.e., the combined finite-discrete element method (FDEM), was employed in this study to examine the first-order seismic capacity of masonry arches and buttressed arches with different shapes subjected to gravity and constant horizontal acceleration. Within the framework of the FDEM, masonry blocks are discretised into discrete elements. A finite element formulation is implemented into each discrete element, providing accurate predictions of the deformation of each block and contact interactions between blocks. Numerical examples are presented and validated with results from the existing literature, demonstrating that the FDEM is capable of capturing the seismic capacities and hinge locations of masonry arch structures. Further simulations on geometric parameters and friction coefficient of masonry buttressed arches were conducted, and their influences on the seismic capacities are revealed.

Evaluation of Behaviour of Plan Curved Structure Supported by Arch

New type of plan curved structure has been developed within the research of arch footbridges at Faculty of Civil Engineering of Brno University of Technology. Structural arrangement came out of study of behaviour of plan curved upper deck arch structures of various radii of curvature. The design method of such structures with ideal shape of arch was the outcome of the research. Results of numerical analysis were verified on physical model in scale 1:10, which has been built and tested. The model has been mounted with gauges – 41 strain gauges at various positions on concrete and steel part of the structure and 5 deflection sensors. Then the structure has been subjected to loads in various positions corresponding with load positions of variable loads in calculation model. The paper describes evaluation of measurement of stresses and deformations of physical model of plan curved structure supported by an arch. Obtained values of stresses and deformations were compared with values derived from FE calculation model.

Transfer relations: useful basis for computer-aided engineering of circular arch structures

Purpose Transfer relations represent analytical solutions of the linear theory of circular arches, relating each one of the kinematic and static variables at an arbitrary cross-section to the kinematic and static variables at the initial cross-section. The purpose of this paper is to demonstrate the significance of the transfer relations for structural analysis by means of three examples taken from civil engineering. Design/methodology/approach The first example refers to an arch bridge, the second one to the vault of a metro station and the third one to a real-scale test of a segmental tunnel ring. Findings The main conclusions drawn from these three examples are as follows: increasing the number of hangers/columns of the investigated arch bridge entails a reduction of the maximum bending moment of the arch, allowing it to approach, as much as possible, the desired thrust-line behavior; compared to the conventional in situ cast method, a combined precast and in situ cast method results in a decrease of the maximum bending moment of an element of the vault of the studied underground station by 46%; and the local behavior of the joints governs both the structural convergences and the bearing capacity of the tested segmental tunnel ring. Originality/value The three examples underline that the transfer relations significantly facilitate computer-aided engineering of circular arch structures, including arch bridges, vaults of metro stations and segmental tunnel rings.