Differences In Structural Behavior Research Articles

The Effect of Steel Over Strength Ratio on Structure Behavior

Seismic design of steel building structures according to SNI 7860:2020 determining the necessary strength of structural members based on the expected yield stress, Ry.Fy, and the expected tensile stress, Rt.Fu. However, the values of Ry and Rt in SNI 7860:2020 are not yet based on the testing of steel products in Indonesia and are still based on the provisions in AISC 341-16. This research was conducted by collecting data on steel tensile test results to obtain the over-strength ratio and then modeling the steel frame building using the over-strength steel provisions of SNI 7860:2020 and based on the tensile test results to determine the difference in structural behavior. Based on the tensile test results, WF300 steel has a yield strength ratio (Ry) of 1.78, which is higher than the SNI specification of 1.5, and a tensile strength ratio (Rt) of 1.35, which is higher than the SNI specification of 1.2. Based on pushover analysis, the deviation value at the initial formation of the plastic hinge on Structure A1 (Ry=1.5) in the x-axis direction of 79.352 mm is smaller than Structure B1 (Ry=1.78) by 94.01 mm. This indicates that the plastic hinge of Structure A1 is formed earlier than Structure B1.

Molecular dynamics of the human RhD and RhAG blood group proteins.

Introduction: Blood group antigens of the RH system (formerly known as "Rhesus") play an important role in transfusion medicine because of the severe haemolytic consequences of antibodies to these antigens. No crystal structure is available for RhD proteins with its partner RhAG, and the precise stoichiometry of the trimer complex remains unknown. Methods: To analyse their structural properties, the trimers formed by RhD and/or RhAG subunits were generated by protein modelling and molecular dynamics simulations were performed. Results: No major differences in structural behaviour were found between trimers of different compositions. The conformation of the subunits is relatively constant during molecular dynamics simulations, except for three large disordered loops. Discussion: This work makes it possible to propose a reasonable stoichiometry and demonstrates the potential of studying the structural behaviour of these proteins to investigate the hundreds of genetic variants relevant to transfusion medicine.

Seismic vulnerability assessment through global-and local-scale analyses for a historic masonry building constructed in 1896

The causes of collapse in masonry buildings are different than those of reinforced concrete and steel-framed buildings. This is due to differences in structural behavior as a result of the materials and techniques used in the construction of such buildings. The most significant contribution to this behavioral difference is made by the out-of-plane behavior of masonry buildings. Therefore, in addition to overall collapse, out-of-plane behaviors of the facade walls must also be determined in such buildings. Accordingly, not only global behavior but also local behaviors should be considered while evaluating structural performance. This paper, therefore, presents a seismic performance assessment of a masonry building by global-and local-scale analyses. The examined 3-story building was constructed in 1896 and used for different purposes. Linear, nonlinear, and kinematic limit analysis approaches were used. Shear forces on the walls and inter-story drifts obtained by the linear and nonlinear analyses were analogized with the limit values envisaged in the local building codes, thus the seismic vulnerability of the building was determined. Overturning, vertical bending and lateral bending mechanisms were obtained by local analysis

Laboratory and numerical analysis of failure of stone masonry arches with and without reinforcement

Nowadays, there are several existing masonry arch structures which are usually protected. Therefore, the maintenance and determination of their load-bearing capacity is a very important issue. Consequently, it is necessary to understand the behaviour of these structures, but the investigation of an old structure can cause difficulties. Nevertheless, a lot of tests can be performed on a smaller model under laboratory conditions. It is easier to understand their structural behaviour and determine the parameters that significantly influence the load-bearing capacity. It also gives the chance to build and verify a numerical model that can be used to model existing structures. In this research, destructive tests of small scale stone masonry arches were performed under laboratory conditions. The analyses were carried out with and without reinforcement to determine the differences in structural behaviour, load-bearing capacity, and failure type. For the tests, carbon fibre reinforced polymer (CFRP) plates were used to strengthen the arch. The properties of the building materials of the stone masonry arches were tested. The paper presents the results and experiences of the construction and the loading of small scale masonry arches. Furthermore, it gives a comparison between the behaviour of reinforced and unreinforced structures.

Phase transitions in the hexagonal tungsten bronze RbNbW2O9

The hexagonal tungsten bronze RbNbW2O9 is shown, by variable-temperature powder neutron diffraction and symmetry-mode analysis, to display a significantly different phase transition sequence compared to the related CsNbW2O9 composition. At ambient temperature, RbNbW2O9 adopts the polar orthorhombic space group Cmc21. Upon heating, the thermal evolution of the crystal structure proceeds via two transitions. These correspond to sequential loss of two distinct octahedral tilting modes, leading to space group P63mc at around 655K, and space group P6mm near 700 ​K. The polar distortion is retained up to the highest temperature studied here. The differences in structural behaviour between the proper ferroelectric RbNbW2O9 and the improper ferroelectric CsNbW2O9 emphasises the need for careful crystallographic analyses of materials of this type.

Experimental investigation on fatigue behavior of steel reinforced concrete composite beam-to-girder joints

Fatigue behavior and failure mechanism of steel reinforced concrete (SRC) beam-to-girder joints is discussed in this paper, which is intended for use in high-speed railway station structures due to their high stiffness and load capacity. Three identical SRC beam-to-girder joint specimens were designed and tested under static loading and two stages of fatigue loading. In the first stage of fatigue loading, the specimens were subjected to design fatigue load for 2 million cycles, while during the second stage, the specimens were loaded to failure under increased fatigue loading amplitude in order to know its fatigue strength and failure mechanism. The constructional details of SRC beam-to-girder joint specimen and the method of loading and testing are presented. The comparison in structural behavior of the joint is made between under static and fatigue loading. Fatigue failure characteristics of the joint are described in detail. It is found that the SRC beam-to-girder joints remained in their elastic range and the concrete surface crack did not exceed 0.1 mm when subjected to design static loading and 2 million cycles of design fatigue loading. There was no significant difference in structural behavior of each component of SRC composite beam between static and fatigue loading. Fatigue failure occurred after these joints were applied higher-level fatigue loading for another 0.70 to 0.91 million cycles. Fatigue crack was initiated at the tension flange of I-shape steel of beam connected by welding to the flange of I-shape steel of girder or at the hole in tension flange of I-shape steel of beam, and then the crack propagated along flange width and web height of the I-shape steel in beam until the I-shape steel lost loading capacity due to lack of enough cross section. The fatigue behavior of constructional detail of the I-shape steel played a key role in the fatigue strength of the SRC beam-to-girder joints. Discussions on improving the fatigue strength of SRC beam-to-girder joints and future research aspects are presented finally.

Origin of the Difference in Structural Behavior of Poly(acrylic acid) and Poly(methacrylic acid) in Aqueous Solution Discerned by Explicit-Solvent Explicit-Ion MD Simulations

The conformational and hydration behavior of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMA) in dilute aqueous solution, as a function of charge density, is studied using two different sets of force field parameters: FF-1 and FF-2. The two sets of force field parameters predict similar correlation distances between carboxylate groups and water. The simulations bring about the difference in the interaction of the counterions with the polyions PAA and PMA. FF-1 predicts that upon neutralization PMA shows stronger correlation with Na+ ions in comparison to PAA in aqueous solution. This difference in behavior agrees with the fact that, in poor solvents, the polyelectrolyte chain and the counterions interact strongly. The atomistic simulations using FF-1 parameters presented here bring about the difference in the conformational behaviors of PAA and PMA and the effect of solvent quality on the polyacrylate chain backbone structure.

반복하중을 받는 하이브리드 프리캐스트 보-기둥 접합부의 성능평가

이 연구에서는 시공성과 경제성이 향상되고 중진 지역에서 사용할 수 있는 새로운 프리캐스트 콘크리트 보-기둥 접합부 상세를 복합구조로 개발하고 실험을 통하여 이를 검증하였다. 이 상세는 기둥 속에 매립된 각형강관과 보U형 단부를 갖는 보 단부에 매립된 플레이트를 볼트로 결합시킬 수 있는 구조로 되어있다. 하이브리드 스틸-콘크리트 접합합부에 앞서 콘크리트가 조기에 파괴되는 것을 막기 위하여 접합부 부분에 ECC(engineered cementitious composite)를 사용하였다. 개발된 접합부 상세에 대한 성능을 검증하기 위하여 보-기둥 접합부 실험체를 계획하여 이에 대한 내진성능 실험을 실시하였다. 내부 접합부에 있어서는 접합부 횡보강근 유무와 현장타성 범위를 변수로 3개의 실험체를 제작하였다. 실험은 기둥에 일정 축력을 가한 상태에서 PC기둥 단부에 액츄에이터를 설치하여 변위제어로써 반복가력 하여 실시하였다. 실험에서 얻은 자료를 접합부 내력, 강성, 에너지 소산능력 등에 대하여 분석하였으며, 그 결과 이 연구에서 제시한 새로운 보-기둥 접합부 상세는 강재와 콘크리트 그리고 ECC 사이에서의 다른 부착 특성 때문에 구조거동에서 차이점이 관찰되었으며, 기준 실험체를 제외한 두 실험체의 경우 ECC 및 철골연결재에 의해 소성힌지를 유도할 수 있는 것으로 나타났다. 그리고 프리캐스트 접합부는 높은 일체성과 모멘트 저항 능력을 보이며 중진 지역에서 사용 가능함을 보였다.

Comparative experimental study of hot-rolled and cold-formed rectangular hollow sections

Square and rectangular hollow sections are generally produced either by hot-rolling or cold-forming. Cross-sections of nominally similar geometries, but from the two different production routes may vary significantly in terms of their general material properties, geometric imperfections, residual stresses, corner geometry and material response and general structural behaviour and load-carrying capacity. In this paper, an experimental programme comprising tensile coupon tests on flat and corner material, measurements of geometric imperfections and residual stresses, stub column tests and simple and continuous beam tests is described. The results of the tests have been combined with other available test data on square and rectangular hollow sections and analysed. Enhancements in yield and ultimate strengths, beyond those quoted in the respective mill certificates, were observed in the corner regions of the cold-formed sections—these are caused by cold-working of the material during production, and predictive models have been proposed. Initial geometric imperfections were generally low in both the hot-rolled and cold-formed sections, with larger imperfections emerging towards the ends of the cold-formed members—these were attributed largely to the release of through thickness residual stresses, which were themselves quantified. The results of the stub column and simple bending tests were used to assess the current slenderness limits given in Eurocode 3, including the possible dependency on production route, whilst the results of the continuous beam tests were evaluated with reference to the assumptions typically made in plastic analysis and design. Current slenderness limits, assessed on the basis of bending tests, appear appropriate, though the Class 3 slenderness limit, assessed on the basis of compression tests, seems optimistic. Of the features investigated, strain hardening characteristics of the material were identified as being primarily responsible for the differences in structural behaviour between hot-rolled and cold-formed sections.

Composite Beams Subjected to Static and Fatigue Loads

This paper presents experimental results of 44 composite beam structures tested under static and fatigue loads. While designing the specimens, variables considered included: (1) the number of shear studs; (2) reinforcing method (deformed bars versus welded wire fabric); and (3) load levels and load ranges for fatigue tests. Results show that (1) cracks were initiated in the concrete slab; (2) propagation and connection of cracks led all specimens to fail; (3) the shear studs become stressed after formation of the cracks; (4) crushing of concrete near the shear studs was observed in some fatigue tests; and (5) the flexural stiffness of the specimens decreased through fatigue tests. The specimens containing wire mesh are superior to those containing steel bars. Moreover, no practical difference in structural behavior was found between the full composite and the 80% composite specimens.

Calculation Of Load And Deformation Behavior Of Structure Elements Taking Into Account 3-dimensional Heat Flow

This paper describes a numerical method for the calculation of load and deformation behavior of structural elements taking into account 3-Dimensional heat flow. The 3Dimensional heat flow influences the temperature distribution in the area of beam-to-column, beam-to-slab and slab-to-column connections. Because of this, the temperature distribution in the longitudinal direction is different between 2-D and 3-D calculations. However, the difference in structural behavior is small, when comparing calculation results from 2-D and 3-D analysis with test results of single elements under standard fire conditions.

Large-angle articulated beam truss design methodology considering offset joint modeling

Adaptive space structures (deployable trusses, large space antennas) can use actuated members to vary their geometry. In particular, variable geometry trusses can use the same set of actuators for both deployment and subsequent articulation. Such articulating trusses can be applied in space crane orbital construction applications. Previous structural analyses have used idealized truss models; members connect at a point at each node. Further analysis of practical truss models in articulated geometries will show the difference in structural behavior compared to ideal trusses and the need to include realistic geometric modeling, such as including the hinge offsets to give the correct packaged truss geometry. An analytic example truss verifies the finite element modeling technique used. Stiffness sensitivity trends for a range of articulated geometries reveal two causes of stiffness reduction: decreased truss effective bending inertia because of shortened actuators and batten bending caused by asymmetric geometry and hinge offsets. The analyses lead to a structural design methodology, including an initially curved geometry, to alleviate the stiffness reduction for improved structural performance. The initially curved articulating truss allows the location of maximum stiffness to be designed and provides compact packaging, self-deployment, and geometric articulation. c d[ E F

Vibrational Characteristics and Structure of Heavy Metal Fluoride Glasses Containing Thorium and Zirconium

This paper reports a vibrational spectroscopic study of a series of glasses composed of Li-Ba-Th-Zr-fluoride in which Th/sup 4 +/ is progressively replaced by Zr/sup 4 +/. In these glasses, Zr/sup 4 +/ shows a more pronounced variation in coordination number than previously observed. Distinct infrared reflectance and polarized Raman bonds due to Th/sup 4 +/ polyhedra are present only in the glasses containing less than 10 mole% ZrF/sub 4/. In the glasses containing 10 or more mole% ZrF/sub 4/, Raman and infrared bands due to Zr/sup 4 +/ polyhedra dominate the vibrational spectra, even in glasses where the ThF/sub 4/ concentration is greater than the ZrF/sub 4/ concentration. The difference in structural behavior or the Th/sup 4 +/ polyhedra as compared to the Zr/sup 4 +/ polyhedra is believed to be due to the smaller electric field intensity of the Th/sup 4 +/ and to the relatively restricted ability of Th/sup 4 +/ to vary its coordination number in response to the availability of F/sup 1 -/.

Deterministic seismic design procedures for reinforced concrete buildings

A brief review is given of a deterministic design philosophy with respect to earthquake resisting ductile structures for reinforced concrete buildings. This was developed recently mainly in New Zealand. In this approach a preferred hierarchy in the development of energy dissipating mechanisms is postulated. Some applications of ‘capacity design procedures’ relevant to beams, columns and shear walls, are outlined. The paramount importance of quantifiable good detailing is emphasized and the relevance of this with respect to shear effects in plastic hinges, the confinement of compressed concrete, and bond between reinforcement and concrete are examined. These aspects of the specific seismic environment are also utilized to show fundamental differences in structural behaviour when effects of gravity loads or seismic displacements are compared.

Use of small models in design and analysis of prestressed-concrete reactor vessels

A series of small prestressed-concrete reactor vessel (PCRV) models was analyzed and tested to investigate the suitability of small-scale ( ≤ 1 20 ) mortar models and epoxy models for determining elastic stress distributions and cracking and failure modes of concrete vessels, and to demonstrate the relative accuracy of two- and three-dimensional elastic finite-element structural analyses of PCRV's. In addition to a small concrete vessel that served as the prototype, there were two small-scale mortar models, a prestressed epoxy model, and a simple axisymmetric epoxy model. The test results from each model were compared with those from the other models and with finite-element predictions. The prototype and the two mortar models were tested to failure with internal pressure. The prototype and one mortar model were pressurized hydraulically, but the other mortar model was tested pneumatically to examine possible differences in structural behavior. The epoxy models were tested in the elastic range only. Structural behavior of the small-scale mortar models closely duplicated that of the concrete prototype. The behavior characteristics of the two mortar models indicated that failure, whether caused by pneumatic pressure or hydraulic pressure, was gradual and not catastrophic. Both two- and three-dimensional finite-element analyses were used to analyze the models, and comparison of the predicted behavior with test results showed reasonably good agreement, even with the two-dimensional analyses, thus demonstrating the reliability of the finite-element computer analyses currently being used for evaluating PCRV's.