Tension Members Research Articles

TENSILE FABRIC STRUCTURES. WORLD CONSTRUCTION EXPERIENCE AND PROSPECTS

The article is devoted to tensile fabric architecture. On the examples of the historical world experience in the construction of structures with tensile fabric coverings, the advantages and ways of further propagation of tensile fabric architecture are considered.
 The successful development of architecture in the context of scientific and technological progress is inextricably linked with the use of advanced achievements in various fields of science and technology and, above all, with the use of progressive structural systems and new effective building materials.
 Among modern building structures, the most rational for medium-span structures and the only possible for large-span structures are spatial coating systems. They allow, without a significant increase in labor costs for the manufacture and consumption of materials, in comparison with flat structures, to free the space to be overlapped from intermediate supports. This ensures the versatility of the use of the building, its more intensive operation, slows down its obsolescence, creates the necessary conditions for its adaptation to new functional and technological processes.
 Tensile fabric structures for roofing stand out from the spatial structures. They are economical, less material-intensive, have rich volumetric plastic capabilities and artistic and decorative qualities. Tensile fabric structures are building structures in which the main load-bearing elements mainly flexible (nets, cables, ropes, curved threads from rigid elements, etc.). These elements works exclusively in tension, which makes possible to use fully the load-bearing properties of high-strength materials (mainly steels). Due to the low weight of such structures, it is possible to cover a large space.
 Tensile fabric structures are widely used in construction. They influence the formation of the architecture of large-span structures, they are used in buildings with complex volumetric-spatial solutions, and their plastic qualities enrich the artistic palette of the architect.
 Tensile fabric coverings are successfully used in construction. The combination of steel tension members and modern synthetic materials makes it possible to create unique and effective solutions for both public buildings and industrial or agricultural structures.

Load Combinations for the Evaluation of Redundancy in Steel Bridges

Over the past decade, there has been considerable interest in the development of quantitative analytical procedures to determine if a primary steel tension member (PSTM) is a fracture critical member (FCM). Traditionally, this designation has most often been arbitrarily determined based simply on the bridge geometry, for example, the number of girders in the cross section, rather than an evaluation of the bridge in the faulted state. Clearly, such a redundancy evaluation must address the loading scenarios concurrent with failure of the PSTM, the likelihood of the member failure, the acceptable probability of load exceeding resistance in the faulted state, and the application of vehicular live load models. This research was conducted to develop a load model and load combinations that are specific to evaluating the performance of a bridge in the event a steel member was to fracture. Specifically, two load combinations were developed to evaluate the strength of a steel bridge, one for the event in which the failure of a PSTM occurs, and another for a post-failure service period. The development adhered to the reliability-based principles and procedures applied in the calculation of load combinations currently used in bridge engineering to facilitate direct implementation and to ensure consistency with current steel bridge design and evaluation procedures contained in the AASHTO LRFD Bridge Design Specifications.

In-Situ Condition Monitoring in Timing Belts for Automation Purposes -Challenges and Opportunities

The wear of tension members in timing belts results in a change in the pre-tensioning force. Therefore, a sensing timing belt was developed to measure the pre-tensioning force. For this purpose, a sensor system is integrated into a tooth, with which the acceleration is measured and sent to an external receiver via Bluetooth. In this publication, the detectability of the natural frequencies under different operating conditions is investigated. The acquired data is separated into span specific segments, as each trum segment has different natural frequencies. This paper will analyse occurring disturbance factors and evaluate the detectability of the natural frequencies.

Parametric study of tensegrity structures under seismic loading

Tensegrity structures are spatial structures made up of an assembly of pin-jointed, prestressed continuous tension members and discontinuous compressive members, arranged in different complex shapes. Limited research has been carried out to analyse the dynamic response of these structures under seismic loading. This paper presents a parametric study to identify the suitability of different forms of these structures under combined vertical gravity and lateral seismic loadings. Different tensegrity shapes were analysed, as simplex and complex structures, under wind and earthquake loadings. These responses of the structures were also compared to that of conventional steel structures of the same shapes. Different parameters such as the effect of varying bar diameter, bar thickness, cable diameter, and tower height, were studied, and behavioural trends were identified. It was found that if a suitable tensegrity shape is chosen and optimized, its behavioural trends can be very similar to that of the conventional steel structures, while saving materials and therefore cost. Modal frequencies of the structure were also identified and found to be low, which is beneficial under earthquake loading. Thus, these systems can prove to be a valuable replacement to conventional systems under adverse dynamic loading.

Development of a hysteretic model for steel members under cyclic axial loading

Steel members present complex nonlinear behaviors due to the asymmetry of the seismic responses of steel members in tension and compression. This research proposed a hysteretic model for predicting the nonlinear behaviors of hot-rolled steel members under cyclic axial loading. The proposed hysteretic model overcomes the notable limitations of the existing hysteretic model and presents considerable advantages. There are a set of linear segments involved in the proposed hysteretic model and each segment is explicitly defined. The recommended values for the empirical parameters included in the proposed hysteretic model are determined through an optimization analysis based on the genetic algorithm. Compared with the available results of the steel members tested previously by other investigators, the proposed hysteretic model is found to be able to accurately predict the hysteretic curves, peak axial resistances and hysteretic energy dissipations of the steel members. The result comparisons indicate that the proposed hysteretic model realistically presents the complex physical behaviors of members including buckling effects in compression, pinching effects in tension reloading excursion, degradation of post-buckling strength, and degradations of subsequent buckling strength. It is also found that the proposed hysteretic model with the parameters properly selected can successfully replicate the hysteretic responses of the steel members tested previously in spite of their differences in cross-sectional shapes, slenderness ratios and end boundary conditions. Moreover, the genetic algorithm enables to identify the approximate parameters included in the mathematical expressions of the proposed hysteretic model with little computational effort.

A comparative assessment of ASM4 rockfall barrier modelling

One key element of flexible rockfall barriers is the net which intercepts the block trajectory. The ASM4 ring net is one of the widely spread net technology for medium to high energy impacts. The accurate modelling of its mechanical behaviour has thus been the aim of many research programs, most of which use the discrete elements method and tension members with material non-linearities. This paper proposes hence a comparison of the three main families of models: linear spring models, tensile ring models and flexural ring models. First, homogenisation techniques are used to characterise intrinsic properties at local scale. Then, the question of the experimental identification of these properties is addressed. Afterwards, the relevance of the identified behaviour is investigated through two case studies. The first one consists in a simple hyperbolic paraboloid structure which has a closed form solution involving large displacements. The second one is based on an experiment on a reduced scale barrier with centred impact and extend the comparison to various kind of data and loading cases. The conclusion presents the main results of the various comparisons, it gives insight on the features that each model can capture and provides some guidelines for designers at early stage design.

Global Sensitivity Analysis of Ultimate Limit States of Stainless Steel Structural Members

The article presents global Sobol sensitivity analysis of a rolled member in tension made from austenitic chromium-nickel stainless steel of type 1.4307/AISI 304 L. The statistical characteristics of yield strength and of the geometry of the rolled steel IPE cross-section are presented on the basis of published experimental research. The sensitivity analysis showed the dominant effect of the yield strength on the static resistance. The second dominant variable is the flange thickness. Higher-order sensitivity indices oriented at detecting the presence of interaction effects between input variables are very small. The characteristics of other types of sensitivity analyses oriented at quantiles or the probability of failure are discussed, especially in terms of a higher proportion of higher-order sensitivity indices. The results of Sobol sensitivity analysis of stainless steel are compared with similar results of carbon steels.

Corroded Tension Chord Model: Load‐deformation behavior of structures with locally corroded reinforcement

AbstractLocalised corrosion may considerably impair the load‐bearing and deformation capacity of reinforced concrete structures. The Corroded Tension Chord Model allows investigating the related effects. The model combines the effects of tension stiffening and strain localisation due to a local cross‐section loss to calculate the load‐deformation behaviour of tension members and entire structural elements containing locally corroded reinforcing bars on a sound mechanical basis. Based on simple equilibrium considerations, the critical loss of cross‐sectional area is introduced, beyond which most of a reinforcing bar's ductility or a structure's deformation capacity, respectively, is lost. For conventional European reinforcing steel, even small cross‐section losses may be sufficient to impair ductility drastically. Illustrative calculations on structural elements with various spatial corrosion distributions but identical mean cross‐section loss reveal that the load‐deformation behaviour strongly depends on the specific corrosion parameters: Structures with few heavily corroded reinforcing bars seem to be less critical regarding strength and deformation capacity than structures with many slightly corroded reinforcing bars.

Numerical Analysis of Cold rolled structural steel angle sections subjected to tension members

Finite element method is a precise and flexible technology for predicting the performance, load conditions of a structure, mechanism or process. During the tests, the structural behaviour was used to build a FEM, especially for the nonlinear analysis. As the failure approaches, angles under tension exhibit non-linear behaviour. Everything is constructed, including the static structural component and all of its modules. Like ANSYS MAPDL modules (Mechanical Ansys Parametric Design Language). Build geometry, define materials, generate mesh, apply load, solving the model, and reviewing the results are all part of the static analyses of FEA. In order to determine the various structural investigations of a single or double section, a number of models have been developed. There were 72 specimens used in the analysis; they were modelled by bolt tensioners that were attached to the specimen. In order to calculate equivalent stress, equivalent elastic strain, and total deformation of single angle and double angle sections, equivalent stress, elastic strain, and total deformation of single angle and double angle sections were examined. In order to find out the ultimate load-carrying capacity of the single angle specimens and double angle specimens, a non-linear static analysis was done. The findings from the experiments, computational codes, and worldwide investigations into load capacity tension members are detailed in the paper. Failure modes are observed, too. In an ANSYS simulation using a numerical model, which used the ANSYS angle algorithm, researchers discovered that experimental and international codes values closely match each other.

Experimental Study on Axial Tension Members of a New Epoxy Resin Concrete

Epoxy resin concrete, as a new kind of polymer concrete, holds a good application prospect because of its excellent material properties, such as high strength, good crack resistance, and others. In this workr, the material tensile property and axial tensile member stress performance of epoxy resin concrete were studied via axial tensile experiments. Before experiments, the original set of drawing clamps on the tester was replaced with a customized steel plate clamps to suit the size of the tensile specimen. The results showed that epoxy resin concrete has better tensile strength and crack resistance compared with ordinary concrete, as well as material uniformity and good integrity. The relevance of the results reported in this work is that the mechanical property study on axial tension members of the new epoxy resin concrete allows improving the tensile failure mechanism and design theory basis of new epoxy resin concrete as structural members, which provides strong support for further study on the development of epoxy resin concrete. The cracking axial force of the epoxy resin concrete was 118 kN, which is 68.6% higher than the ordinary concrete.

Analysis of the Shear Lag Factor for Slotted Rectangular HSS Members

Rectangular HSS tension members are often connected by slotting two opposite walls and welding the slotted walls to a gusset plate. Due to a nonuniform stress distribution in these connections, the tensile rupture strength of the member is dependent on a shear lag factor. The accuracy of the 2016 AISC Specification provisions for the tensile rupture strength of slotted HSS tension members was evaluated using existing data from five previous research projects. The results revealed that the current equations are excessively conservative. The accuracy can be improved by replacing the existing equation for the connection eccentricity with the equation proposed in this paper.

Failure Modes Of Cold Formed Steel Angle Sections

Tension members consisting of single and double angles, single channels and similar sections are frequently used for lateral bracing and as truss elements. Such members normally have eccentric connections which results in bending of tension member. It is often permitted, by current design specifications, to neglect this eccentricity in the design of the member. The present study is focus on mode of failure on cold formed steel angle. This analysis carries single angles and double angles sections of 2mm under plain (without Lipped) and with Lipped conditions subjected to tension. Analyses were carried out for thirty-six numbers of angle sections under condition such as double angle were connected same side to gusset plate and connected to opposite side. Figure shows connection failure and mode of failure. Local buckling, global buckling, tearing failure, net section failure, and block shear failure.

Analysis Of Light Gauge Steel By Using Fem Subjected To Tension Load

The effective sectional area concept was adopted to conduct the analysis of cold-formed Tension members. ANSYS software was utilized to simulate the behavior of cold-formed steel angle under tension load. The paper describes the results from a finite element investigation into the load capacity tension members of single angle sections of 1.5,.1.6,2 3,4 mm and double angles sections of 2mm under plain (without Lipped) and with Lipped conditions subjected to tension. Numerical investigations were carried out using finite element software ANSYS. In order to simulate the experimental behavior using the analytical model, material non-linearity’s and geometric nonlinearity’s were incorporated. The ultimate strength for cross – sectional dimensions with varying eccentricity loads under tension loading conditions was achieved through the ANSYS 15.0 workbench. In the numerical investigation, 180 specimens were modeled on tensioning elements attached to bolts. To find equivalent stress, equivalent elastic strain and total deformation of single and double-angle sections were investigated.

A Study on the Shear Lag Effects in Longitudinally Welded Connections Subject to Eccentricity

AbstractIn United States design specifications, shear lag in longitudinally welded connections is accounted for by means of a tabulated factor, which until 2010 was only applicable to plate‐type members having equal length welds on each side, subject to the further constraint of having a minimum weld length equal to the distance between the welds. This created the paradox that connections with longitudinal welds shorter than the distance between the welds were considered by the Specification to have no capacity at all. Research in extant literature based on historical experimental data developed alternative factors that augmented and replaced the previous approaches, making them applicable to longitudinally welded plates, angles, channels, tees, and wide‐flange shapes having equal or unequal weld lengths, and without any weld length‐to‐connection width limitation. This paper presents the results of an experimental study of shear lag effects in longitudinally welded tension members under both in‐plane and out‐of‐plane eccentricity. Forty specimens were tested representing twenty configurations and the experimental results were compared to three theoretical values – (a) the shear lag factor from the 2016 American Institute of Steel Construction (AISC) Specification, (b) the shear lag factor based on a bi‐planar model found in literature, and (c) the shear lag factor from the 2010 AISC Specification. It is concluded that the shear lag factor provided in the 2016 AISC Specification offers the best prediction of the capacity of longitudinally loaded welded connections subject to both in‐plane and out‐of‐plane eccentricity.

Torsional load-bearing capacity of half-shell segments for prestressed concrete towers

This article deals with the torsional load-bearing behaviour of concrete half-shell structures. The analogy between the bending stressed tension members according to second order theory and torsional members with warping hindered cross-section leads to a significantly simplified calculation of the additionally occurring warping stresses. This eliminates the need for the laborious solution of complex differential equations of the classical torsional warping theory to determine the load-bearing behaviour of warped cross-sections. The load redistribution approach projects the global torsion load of the segment tower onto the individual half-shell. The combination of the two approaches enables the analytical calculation of the torsional load-bearing behaviour of the concrete half-shell construction as a function of the global torsional moment and the system variables of the half-shell.The objective is to investigate and describe the torsional load-bearing behaviour of segmented half-shell structures in an engineering model. Compared to closed circular ring segments, the vertical joints have a significant influence, especially on the torsional rigidity. In order to determine the horizontal joint bearing capacity of these innovative constructions, it is essential to understand the load transfer of the torsional load. The presented approach allows to separate the individual effects of the load transfer in half-shell constructions from each other and thus to identify the factors influencing the torsional load-bearing behaviour.

Models of Transverse Vibration in Conveyor Belt—Investigation and Analysis

The transverse vibration frequency of conveyor belts is an important parameter describing the dynamic characteristics of a belt conveyor. This parameter is most often identified from theoretical relationships, which are derived on the basis of an assumption that the belt is a stationary elastic string. Belt vibrations have a number of analogies to other tension member systems, such as, for example, power transmission belts. Some research findings suggest that in the case of a limited length of the belt section, a more accurate description of its vibration can be obtained with a beam model rather than with a string model. Experimental research has so far mostly revolved around measurements of stationary belts. This article presents the results of vibration measurements performed for a moving belt and obtained for various operating parameters of the conveyor, as well as for several configurations of the distance between idler supports. The analysis was conducted on a moving steel-cord belt. Belts of this type are commonly used in the majority of mines and industrial plants. The measurement results were compared with the model of a string and with the model of a beam in tension. Both of the theoretical models allowed for the belt speed, whose influence was demonstrated in both theoretical calculations and experimental tests to be negligible. On the other hand, the tensile force in the belt was observed to have a significant impact on the vibration frequency. Depending on the idler spacing, the measurement results are approximate to those of the beam model or of the string model. For spacing smaller than 1.6 m, the belt shows properties approximate to an elastic beam, while for spacing greater than 1.6 m, the belt behaviour can be better represented through a string model. A beam model is, therefore, more applicable in analyses of vibrations in the upper strand of the belt, while a string model is more useful in analyses of vibrations in the lower strand.

Modeling and analysis of a pin jointed plane frame using Biomimicked structural elements

Biomimicry can be termed as the concept that involves the imitation of models, systems and elements of the nature to solve complex human problems. When compared to the conventional techniques, it is an efficient, innovative and sustainable way and thus has scope in future. The various levels in biomimicry are utilized in the construction of the structures inspired from the nature thus paving way to innovation and sustainability. Various information can be learnt from nature when it comes to solving our challenges in a sustainable way. Nature builds to shape, because shape is cost effective and it minimizes the expenditure on materials while maximizing the effectiveness to achieve the desired functions. In this study the analysis of the conventional pin jointed plane frame is done first using STAAD. Pro to identify the compression and tension members in the frame. The various conventional frame models are modelled and analyzed. The finite element analysis is done using ANSYS 2020R2. A conventional pin jointed plane frame of height 4 m, bay width 4 m and strut length of 5.66 m were analyzed to know its member properties. A conventional pin jointed frame with horizontal springs provided at both the sides of the frame was modelled and analyzed. The optimized mimicked members are assembled to form the mimicked frame and analyzed. The various parameters such as total deformation, directional deformation, normal stress, equivalent stress, maximum principal stress and minimum principal stress were compared for the pin jointed plane frames. The present study helps in the reduction of material usage and self-weight of elements thus resulting in a sustainable and efficient structure

Evaluation of bond‐slip behavior of reinforcement in ultra‐high‐performance fiber‐reinforced concrete

AbstractBond strength of steel reinforcement embedded in ultra‐high‐performance fiber‐reinforced concrete (UHPFRC) plays a vital role in the post‐cracking behavior of reinforced UHPFRC members in flexure or tension. This paper presents an analytical study on the bond strength of steel reinforcement in UHPFRC. Three different bond‐slip models, namely the modified fib model, Marchand model and the proposed model are compared in the analytical method and explicit equations are also proposed. Comparisons with test data suggest that the proposed model and explicit equations can evaluate the bond‐slip behavior of reinforcement with good accuracy. Marchand model shows similar predictions of bond‐slip behavior to the proposed model at different load levels, whereas the modified fib model is accurate only when the reinforcement nearly yields in tension. The embedment length required for embedded reinforcement to develop its yield and ultimate strengths can also be calculated from the analytical method and explicit equations.

Evaluation of Carbon Fiber Grid Reinforced Concrete Panel for Disaster Response and Improved Seismic Performance

The purpose of this study is to enable emergency recovery of damage caused by earthquakes in structures and prevent secondary damage by controlling progressive collapse. Although there have been many previous studies using reinforcing bars and meshes, there have been few studies using carbon grid fibers as a substitute for tension members. This study aims to quantitatively present disaster response seismic performance by manufacturing concrete panels with no layers, one layer, or two layers of carbon fiber grids inserted and to compare the flexural strength and energy dissipation capacity. Flexural strength increased by 7% with one layer and 15% with two layers compared with no layer. Energy dissipation capacity increased by 30 times with one layer and by 56 times with two layers compared with no layers, and showed great improvement in terms of seismic performance. Especially because of the large increase in the energy dissipation capacity, the carbon fiber grid reinforcement method is considered to be an effective method for improving seismic performance.

Behaviour of a single angle tension member welded at single leg and both legs

Behaviour of a single angle tension member welded at single leg and both legs