Cross Beam System Research Articles

ЕКСПЕРИМЕНТАЛЬНІ ДОСЛІДЖЕННЯ СЕРІЙНОЇ ДОРОЖНО-АЕРОДРОМНОЇ ЗАЛІЗОБЕТОННОЇ ПЛИТИ

The results of experimental studies of the load-bearing capacity and crack resistance of the serially produced road-airfield reinforced concrete slab PAG, manufactured at Velikodolinsky Reinforced Concrete Plant LLC by order of the Odessa State Academy of Construction and Architecture, are presented. In accordance with the regulatory documents in force in Ukraine, one of two possible loading schemes was considered ― with a load by a concentrated force applied on the cantilever part of the slab. The slab was tested on a specially made stand, which consists of four support posts connected in pairs by beams on which the slab rested. The load was applied along the width of the slab in steps ― 0.04 from the destructive load, along two concentrated vertical stripes. Each load stage ended with a five-minute hold, at the beginning and end of which readings were taken on the measuring instruments. All tests were carried out using two 30t jacks and a 50t dynamometer. The principle of operation of the jack was that its lower plane pressed on a two-level cross-beam system, and through it the load was distributed onto the slab. During testing, the applied load, deflections and deformations were recorded on the slabs. Dial indicators and deflectometers were used as measuring instruments. The process of crack formation on the surfaces of the slabs was observed using a Brinell tube in the places of the greatest opening of the cracks. As a result of the tests, the load-bearing capacity of the slab was 163.2 kN with a bending moment of 78.3 kNm. The load corresponding to the onset of cracking is 86.4 kN with a bending moment of 36.9 kNm. The maximum crack opening width was 1.0 mm. Based on the indicator readings, graphs of the dependence of relative deformation on load were constructed. Graphs of the dependence of deflections on load are constructed using data from two deflection meters. Before the first crack appears, the maximum deflection of the slab is 12.0% of the deflection recorded at the end of the tests.

EXPERIMENTAL STUDIES OF SERIAL REINFORCED CONCRETE PAG SLAB WITH ADDITIONAL STEEL FIBER REINFORCEMENT

Thus, in laboratory conditions, experimental studies of the bearing capacity and crack resistance of a serial PAG plate with additional steel fiber reinforcement in the amount of 1% were carried out. In accordance with the regulatory documents in force in Ukraine, one of two possible load schemes was considered ― when loaded by a concentrated force applied to the cantilever part of the slab. The plate was tested on a specially made stand consisting of four support racks connected in pairs by beams on which the plate rested. The load was applied across the width of the slab in steps of 0.04 from the destructive load, in two concentrated vertical strips. Each level of load ended with a five-minute exposure, at the beginning and end of which the readings on the measuring devices were taken. All tests were carried out using two 30-ton jacks and a 50-ton dynamometer. The working principle of the jack consisted in the fact that its lower plane pressed on a two-level cross-beam system, and through it the load was distributed on the slab. In the process of testing the plates, the applied load, deflections and deformations were recorded. Clock-type indicators and protractors were used as measuring devices. The process of crack formation on the plate surfaces was observed with the help of a Brinell tube in the places of the largest crack opening. 
 As a result of the tests, the bearing capacity of the plate was 211.2 kN with a bending moment of 101.4 kNm. The load corresponding to the beginning of crack formation is equal to 96.0 kN at a bending moment of 46.1 kNm. The maximum width of crack opening was 0.25 mm. According to the readings of the indicators, graphs of the dependence of the relative deformation on the load were constructed. Graphs of the dependence of deflections on the load, constructed from the data of two deflection gauges. Before the appearance of the first crack, the maximum deflection of the plate is 17.0% of the deflection recorded at the end of the tests.

Load-Bearing Capacity of Reinforced Concrete and Fiber Concrete Cross-Beam Systems

The results of experimental studies and computer modeling of reinforced concrete and fiber concrete cross-beam systems are presented. The authors have made a special stand, the design of which allows to carry out researches of bearing capacity and deformability of such systems under the concentrated and distributed static loads. Samples made of reinforced concrete and steel fiber concrete and consisting of four mutually perpendicular beams of rectangular cross-section were tested. The specimens were reinforced in the lower zone with longitudinal reinforcement of 8 mm in diameter, two rods in each beam. Steel-fiber concrete specimens have an additional dispersed reinforcement of steel fiber with bent ends in an amount of 1% by volume of concrete. A procedure of finite-element modeling and calculation of cross-beam systems in the licensed program ANSYS 17.1 was developed, and a comparison of the results obtained experimentally and on the basis of computer modeling was performed. The tests showed that dispersed reinforcement of the cross-beam system with steel fiber leads to an increase in its bearing capacity by 1.23 times. During modeling and finite-element analysis in the ANSYS 17.1 program, the increase in bearing capacity was 1.18 times. At the same time, the load-carrying capacity of the reinforced concrete cross-beam system obtained by the finite-element method was 13% lower than in the experiment, and that of the fiber-reinforced concrete system was 15% lower. At the same time, the discrepancy in the approaches considering torsion and not taking it into account is about 5% for all the samples studied in the work.

Experimental and numerical investigation on progressive collapse resistance of RC frame structures considering transverse beam and slab effects

In order to investigate the load carrying mechanisms in resisting progressive collapse for reinforced concrete (RC) structures while considering transverse beam and slab effects, a series of four 1/4-scale RC substructural specimens were tested and the failure modes, load-displacement relationships, and load redistribution responses are presented in this paper. Two beam-column subassemblies were tested as control specimens. The third specimen was a cross-beam subassembly composed of a transverse beam and a longitudinal beam which had the same reinforcement detailing as the control specimens to investigate the transverse beam effects excluding RC slab. The last specimen had identical beams with the third specimen, but including an RC slab to consider the slab effects, which could be used to simulate the mechanism to resist progressive collapse developed in a practical frame structure. Test results showed that the load-carrying capacity of a cross-beam system at the compressive arch stage was almost equal to the sum of the load-carrying capacities of these two crossed beams, whereas the transverse beam and slab effects could increase the capacity of a two-span beam by as much as 340%. Thus, transverse beam and slab effects should not be ignored in the simulation of progressive collapse for RC frame structures. Based on the simplified models calculating nonlinear static load-deflection responses for RC two-span beams proposed in the previous study and load-displacement relationships obtained in this test, computational models calculating load-deflection responses for cross-beam subassembly excluding or including slab were established and verified.

Optimization of the Configuration of Cross-Beam System Dimensional Structure Depending on the Specified

This article presents an analysis of cross-beam systems made of wood-composite materials made of glued wood, highlights their positive aspects, including a significant reduction in the weight of the structure, as well as disadvantages that prevent the spread of this technology in Russia. The experience of calculation and construction of structural plates in Russia is considered. the most progressive method of arrangement of the core structure is determined experimentally. The possibilities of using cross-beam systems for the construction of public buildings and structures are considered.

Разработка технологии монтажа пространственной конструкции на основании экспериментально-теоретических исследований перекрестно-балочной системы

For the prospective development of life in the Arctic zone and the territories of the Far North of Russia, research is needed on the design and development of technologies for the construction of buildings and structures for various purposes. This article considers and analyzes the presently used cross-beam systems made of laminated timber and the principles of calculating these systems. Analytical calculations were carried out, which made it possible to identify the optimal design for the location of the rod system, including the one which significantly reduces the total structural weight. Furthermore, on the basis of the calculations, there was determined the most progressive way of solving the geometric parameters of the spatial rod structure. The technology of installation of laminated wood structures is proposed, and the possibility of its application in the construction of buildings and structures in the severe conditions of the Arctic and the Far North is discussed.

Ion-induced Auger electrons contrast on cross-beam systems

The article deals with the basic aspects of ion-stimulated Auger process. The authors suggested using the standard Everhart–Thornley detector to obtain a contrast of ion-induced Auger electrons on cross-beam systems using mathematical processing of the image which is based on spectroscopic information. As a result, this work consisted of obtaining images that showed the contrast distribution of Auger electrons and the sputtering yield on aluminum thin films samples.

Sensitivity Analysis of Dynamic Characteristics of Steel Plate Composite Girder Bridge with Supported Cross Beam System

A steel plate composite girder bridge with support beam system was selected in the case study and the software of SAP2000 was adopted to build its refined seismic finite element model. A sensitivity analysis about the dynamic characteristics of the bridge was carried out and the design parameters included relative stiffness ratio of beam to slab, shear stiffness of shear nails and steel beam. The results show that: the stiffness ratio of beam to plate has little influence on the low-order modes of structure, but more significant influence on the high-order modes. Furthermore, in the high order modes, the effect of the stiffness of concrete slabs on the dynamic characteristics of high order modes of structures is greater than that of the stiffness of steel girders. Large reduction of the stiffness of shear nails significantly affects the natural vibration period, the order of mode shapes and the mass participation coefficient. Its influence on the vertical dynamic characteristics of bridge is significantly greater than the dynamic characteristics in the longitudinal direction and the in the horizontal direction. Steel beams have little influence on the dynamic characteristics of structures.

Production of excited H–atoms in electron collisions with adenine

Dissociative excitation of adenine (H5C5N5) into excited atomic fragments has been studied in the electron impact energy range from threshold to 400 eV. A crossed beam system coupled to a vacuum ultraviolet (VUV) monochromator is used to study emissions in the wavelength range from 90 to 200 nm. The beam of adenine vapor from a stainless steel oven is crossed at right angles by the electron beam and the resultant VUV radiation is detected in a mutually orthogonal direction. Excitation of the H Lyman series, the strongest features in the spectrum, is considered in detail.

Экспериментальные исследования систем перекрестных балок из деревянных элементов на квадратном плане при изменении динамических и статических нагрузок

Экспериментальные исследования систем перекрестных балок из деревянных элементов на квадратном плане при изменении динамических и статических нагрузок

Collinear, two-color optical Kerr effect shutter for ultrafast time-resolved imaging.

Imaging with ultrashort exposure times is generally achieved with a crossed-beam geometry. In the usual arrangement, an off-axis gating pulse induces birefringence in a medium exhibiting a strong Kerr response (commonly carbon disulfide) which is followed by a polarizer aligned to fully attenuate the on-axis imaging beam. By properly timing the gate pulse, imaging light experiences a polarization change allowing time-dependent transmission through the polarizer to form an ultrashort image. The crossed-beam system is effective in generating short gate times, however, signal transmission through the system is complicated by the crossing angle of the gate and imaging beams. This work presents a robust ultrafast time-gated imaging scheme based on a combination of type-I frequency doubling and a collinear optical arrangement in carbon disulfide. We discuss spatial effects arising from crossed-beam Kerr gating, and examine the imaging spatial resolution and transmission timing affected by collinear activation of the Kerr medium, which eliminates crossing angle spatial effects and produces gate times on the order of 1 ps. In addition, the collinear, two-color system is applied to image structure in an optical fiber and a gasoline fuel spray, in order to demonstrate image formation utilizing ballistic or refracted light, selected on the basis of its transmission time.

AN EXPERIMENTAL STUDY ON THE CONNECTION OF CROSSBEAMS IN A MODULAR BRIDGE

A recently the application of modular bridge system, an assembly of the structural members, has been required to minimize traffic congestion, to reduce the period of construction, and to improve the quality and workability during the new construction and reconstruction of the bridge. For this reason, the modular bridge system is necessary to prepare for near future. In this study, alternative crossbeam system for modular prestressed concrete (PSC) T-girder bridge was developed. Static loading test was performed to inspect the structural characteristics of the alternative crossbeam system. Experimental results were analyzed and compared with each data. Therefore, the appropriate crossbeam system for modular PSC T-girder bridge was proposed.

An Experimental Study on the Connection of Diaphragm in Prefabricated Bridge

A recently new construction and reconstruction of the bridge have been required to minimize traffic congestion, environmental disadvantage, to reduce the period of construction, and to improve the quality and workability during the construction. For this reason, the application of modular bridge system, which is assembly of the structural members, is necessary to prepare for near future. Fall of girders can occur at the moment to connect between precast girders during the construction, so appropriate cross beams should be installed to solve the mentioned problem. In this study, understanding the structural characteristics and status of cross beam, alternative cross beam system for modular bridge was developed. To inspect the structural characteristics of the alternative system, specimens were built and static loading test was performed. Afterward, the behavior of cross beam in terms of joints and load distribution was observed. Experimental results were analyzed and compared with each data. Therefore, the appropriate cross beam system for modular bridge will be chosen and proposed in this paper.

Security: virtualisation's last frontier

Server virtualisation offers the promise of delivering irresistible benefits, including the consolidation of several autonomous servers into a single virtualised environment, the ability to scale the performance of servers as the business grows, the flexibility to quickly adapt to changing business needs and the capability to deliver automation that will keep applications running at peak performance. However, virtualising the server infrastructure is only a small component of deploying an efficient and cost effective datacentre. Many organisations have adopted server virtualisation because of the business benefits it offers. However, key areas of the next-generation datacentre have been overlooked, specifically in the area of network security infrastructure. In order to realise the full potential of the virtualised server architecture, the supporting infrastructure must deliver the same consolidation, scale, adaptability and automation benefits. Transitioning to a virtualised security infrastructure in co-ordination with virtualised servers can properly align the supporting security, explains Brian Robertson of Crossbeam Systems.

조립식 교량의 가로보 연결에 관한 실험적연구

최근 교량의 신설 및 교체 공사 중 요구되고 있는 교통 혼잡의 최소화, 환경 영향의 최소화, 공사기간의 단축, 품질과 시공성 향상 등을 위해 조립식 교량 시스템의 적용이 시대적 요구로 대두되고 있다. 조립식 교량 시공 중 거더 간의 연결 시 발생할 수 있는 전도 및 추락 사고는 교량 시스템에 적합한 가로보의 사용으로 해결이 가능할 것으로 보여 진다. 본 연구에서는 가로보의 구조적 특성을 조사하고 국내 외 적용현황을 분석하여 조립식 PSC T형 거더 교량에 접합한 가로보 대안을 설정하여 가로보 연결부의 특성을 규명하고자 실험체를 제작하여 정적 하중 재하실험을 실시하였다. 정적 하중 실험을 통하여 실험체의 접합부의 거동과 하중분배에 대해 살피고 실험결과를 비교, 분석하였고 실험을 통한 구조 성능의 결과 치, 시공성을 고려하여 조립식 PSC T형 거더 교량에 접합한 가로보 대안을 제안 하였다. Recently new construction and reconstruction of the bridge have been required to minimize traffic congestion, environmental disadvantage, to reduce the period of construction, and to improve the quality and workability during the construction. For this reason, the application of modular bridge system, which is assembly of the structural members, is necessary to prepare for near future. Fall of girders can occur at the moment to connect between precast girders during the construction, so appropriate cross beams should be installed to solve the mentioned problem. In this study, understanding the structural characteristics and domestic and international case of cross beam, alternative cross beam system for modular bridge was developed. To inspect the structural characteristics of the alternative system, specimens were built and static loading test was performed. Afterward, the behavior of cross beam interms of joints and load distribution was observed. Experimental results were analyzed and compared with each data. Therefore, the appropriate cross beam system for modular bridge will be chosen and proposed in this paper.

Large amplitude forced vibration analysis of cross-beam system through energy method

Large amplitude forced vibration behaviour of cross-beam system under harmonic excitation is studied, incorporating the effect of geometric non-linearity. The forced vibration analysis is carried out in an indirect way, in which the dynamic system is assumed to satisfy the force equilibrium condition at peak load value, thus reducing the problem to an equivalent static case. The two beams of the system are solved individually either by a direct substitution method employing successive relaxation technique or a multi-dimensional secant method, known as Broyden’s method. An iterative scheme, based on the reaction force between the two beams of the system and equality of vibration amplitude at the contact of two beams, is developed to obtain the response of the system under external harmonic excitation. The present method is validated through results generated in ANSYS 11.0. The system response is studied for various loading type and contact location of the beams. The results are presented in terms of plots of vibration amplitude of the contact point versus frequency of forcing excitation in dimensional plane. Keywords: Cross-beam, Forced vibration, Geometric non-linearity, Variational methods, Harmonic excitation

Elastic scattering of electrons from alanine

Differential cross sections (DCSs) for elastic scattering of electrons from alanine, have been measured using a crossed beam system for incident energies between 20 and 80eV and scattering angles from 10° to 150°. The experimental data were placed upon an absolute scale by normalisation to calculated absolute integral cross sections obtained using the corrected independent-atom method incorporating an improved quasifree absorption model. The calculated data-set includes DCSs and integral elastic and inelastic cross sections in the incident energy range between 1 and 10,000eV. These theoretical results are found to agree very well with the experimental data both in the shape and magnitude of DCSs except at the smallest scattering angles.

Optical fibre transducer

Server virtualisation offers the promise of delivering irresistible benefits, including the consolidation of several autonomous servers into a single virtualised environment, the ability to scale the performance of servers as the business grows, the flexibility to quickly adapt to changing business needs and the capability to deliver automation that will keep applications running at peak performance. However, virtualising the server infrastructure is only a small component of deploying an efficient and cost effective datacentre.Many organisations have adopted server virtualisation because of the business benefits it offers. However, key areas of the next-generation datacentre have been overlooked, specifically in the area of network security infrastructure.In order to realise the full potential of the virtualised server architecture, the supporting infrastructure must deliver the same consolidation, scale, adaptability and automation benefits. Transitioning to a virtualised security infrastructure in co-ordination with virtualised servers can properly align the supporting security, explains Brian Robertson of Crossbeam Systems.

Formation of H(2p) and H(2s) in collisions of He+ with H atoms

Cross sections for excitation of the H(2p) and H(2s) states in He+-H collisions have been determined within the energy range 2.5-25 keV amu-1. Measurements have been based on observations of both spontaneous and electric field induced Lyman alpha radiation emitted by excited H atoms in a modulated crossed beam system developed previously in this laboratory. The measurements usefully extend previous low energy measurements and allow comparison with a number of theoretical predictions. In general the theory fails to provide a satisfactory description of both the observed magnitude and strong energy dependence of the measured cross sections for this two-electron system.

Chemi-ionization reactions of electronically excited lithium

Chemi-ionization reactions of atomic lithium in the 4 2S1/2 state have been observed with NO2, Cl2, and F2 collision partners in a crossed-beam system. The reaction products have been analyzed with a mass filter to be Li++NO2−, LiCl++Cl−, and Li++F+F−, with reaction cross sections of 0.02, 0.2, and 2×10−16 cm2, respectively.