Lateral Ties Research Articles

Siblings and the Bereaved Self: Identity (Re)Construction Following the Death of a Brother or Sister

Having and being a sibling can be vital in shaping one’s identity. Using data from a qualitative study exploring experiences of sibling bereavement over the life course, this article questions how the death and subsequent loss of a brother or sister impacts upon the way that surviving siblings (continue to) construct their sense of self. It explores how people re-assess the established similarities and differences they shared with living siblings and re-negotiate their positioning within the chronological sibling birth order. In doing so, this article emphasises the sociological importance of lateral kinship ties with siblings, demonstrating that being and having a sibling can have lasting implications for the way that people perceive and present themselves, even after death. As such, the article concludes that the dead can continue to maintain an important and influential, albeit liminal, position in the webs of relationships in which people are embedded.

Investigating dilation response in PET FRP-confined reinforced concrete: Experimental study

In compression, concrete undergoes dilation due to the Poisson’s effect. Beyond the elastic limit, rapid crack propagation causes unstable expansion, leading to stiffness degradation, reduced strength, and ductility. External confinement with fiber-reinforced polymer (FRP) composites effectively manages this dilation, maintaining core integrity at high strength and deformation levels. However, internal steel reinforcement, especially when poorly detailed, can hinder FRP's efficacy by inducing stress concentrations from longitudinal bar buckling, resulting in premature FRP failure. This study addresses this challenge by utilizing polyethylene terephthalate (PET) FRP with a large rupture strain (LRS) capacity to delay premature rupture to high strain levels. Experimental results on poorly detailed reinforced concrete (RC) externally confined with PET FRP are presented, with variables including PET FRP layers, longitudinal bar buckling length, and cross-sectional aspect ratio. Detailed discussions on the effects of these variables on lateral to axial strain ratio, dilation rate, and volumetric response of confined concrete are provided. Test results have shown that PET FRP effectively managed the unstable dilation of confined concrete, even with internal steel reinforcement. Following the yielding of lateral ties and the buckling of longitudinal bars, PET FRP efficiently handled local stress concentrations and redistributed internal concrete damage. Despite PET FRP's low elastic modulus causing significant lateral expansion, its LRS capacity maintained the integrity of the entire column under high deformation.

Comparison of polymethyl methacrylate skull implant fixation by three types of titanium fasteners

To evaluate mechanical strength of three methods of polymethyl methacrylate skull implant fixation in two experimental models. The first experiment was performed on a plastic model that was as close as possible to bone in structural characteristics. The second experiment was performed on a biological specimen (a ram's head). We assessed the quality of implant fixation to bone window edges by craniofixes, ties and microscrews and lateral intercortical screws. Craniofixes are feasible for small flat flaps, but not advisable for wide highly curved implants. They are also the most expensive method of fixation. Implant fixation by ties and microscrews is a universal method comparable in price to craniofix. Lateral intercortical fixation is effective both for small flat implants and wide implants with large curvature. However, this method is not always applicable. Combined fixation by lateral intercortical screws and ties allows for the most effective fixation while reducing the overall price of consumables.

Peak stress and peak strain evaluation of concrete columns confined with lateral ties under axial compression by artificial neural networks

Peak stress and peak strain evaluation of concrete columns confined with lateral ties under axial compression by artificial neural networks

Blast resistance of RC columns for varied detonation scenarios: Effect of shear detailing

The growing threat of accidental and malevolent blast loading to building structures has necessitated the consideration of blast-resistant design. Columns are the most vulnerable and critical component of a building, so they must be designed against blast to achieve defined performance goals. The influence of transverse rebar detailing on the ultimate capacity and failure modes of rectangular reinforced concrete (RC) columns against blast loads was investigated under different detonation scenarios. The performance of the columns was quantified using the failure charge mass and post-blast residual axial capacity. Pressure–impulse diagrams were used to study the failure modes. The analyses showed that special transverse detailing measures were the most effective for columns subjected to near-field surface bursts. The confinement of concrete due to ties and axial restraint played a critical role in improving the blast performance of columns. The provision of diagonal rebar improved the blast resistance by preventing direct shear failure, and was most effective when coupled with closely spaced lateral ties. Finally, the performance of code-compliant columns against blast was studied to determine the blast safety margin and the scenarios under which it would be necessary to undertake blast retrofitting of the columns in existing critical buildings.

Stress–Strain Model of High-Strength Concrete Confined by Lateral Ties under Axial Compression

High-strength concrete can effectively reduce the cross-sectional size, increase space usage, and cut material costs. To analyze the mechanical properties of high-strength concrete vertical members, various confinement models have been proposed to define the ties-confined concrete stress–strain relationship. However, most existing models are divided into ascending and descending segments. These are continuous but not derivable at the peak point, which does not facilitate numerical calculations. Moreover, these models have a large number of parameters that are mostly obtained based on the fitting of experimental data, which may also lead to the limited applicability of the models. In this study, existing confinement models for high-strength concrete under axial compression are reviewed, and the differences between the models are discussed. Based on the results of normal triaxial experiments on high-strength concrete and the test data from other studies on ties-confined concrete columns, the effective confinement coefficient and empirical formula of ties strain at the peak stress of confined concrete are proposed. A confinement model is proposed based on the continuous derivable function, and it is validated based on the available experimental data. Results show that the proposed model can reflect the stress–strain relationship of the test specimens more simply while keeping the basic accuracy with other models.

Investigating the Effect of Parameters on Confinement Coefficient of Reinforced Concrete Using Development of Learning Machine Models

The current research aims to investigate the parameters’ effect on the confinement coefficient, Ks, forecast using machine learning. Because various parameters affect the Ks, a new computational model has been developed to investigate this issue. Six parameters are among the effective parameters based on previous research. Therefore, according to the dimensions of the variables in the problem, a supply–demand-based optimization (SDO) model was developed. The performance of this model is directly dependent on its main parameters, such as market size and iteration. Then, to compare the performance of the SDO model, classical models, including particle swarm size (PSO), imperialism competitive algorithm (ICA), and genetic algorithm (GA), were used. Finally, the best-developed model used different parameters to check the uncertainty obtained. For the test results, the new SDO-ANFIS model was able to obtain values of 0.9449 and 0.134 for the coefficient of determination (R2), and root mean square error (RMSE), which performed better than other models. Due to the different relationships between the parameters, different designed conditions were considered and developed based on the hybrid model and, finally, the number of longitudinal bars and diameter of lateral ties were obtained as the strongest and weakest parameters based on the developed model for this study.

Numerical simulation of axially loaded square high-strength concrete short columns with steel equal-angles as longitudinal reinforcement

Steel Equal-Angle (SEA) can be used to replace the longitudinal reinforcement in concrete columns to improve their strength and ductility. However, as a novel concept of applying SEA as longitudinal reinforcement in concrete columns, experimental and numerical studies are very limited on the behavior of SEA Reinforced Concrete (SEARC) columns constructed with high-strength concrete. This paper presents a numerical simulation model based on the fiber-element method for computing the axial performance of square SEARC short columns loaded axially. The model accounts for the inelastic buckling of SEA sections and confinement effects provided by SEA to the confined concrete. Available test data is used to examine the accuracy of the numerical model. It is shown that there is a good agreement between numerical simulation and experimental data. The numerical model is employed to investigate the influences of important parameters on the responses of short SEARC columns subjected to axial compression. It is demonstrated that the strength and ductility of SEARC columns are significantly affected by the width of SEA sections, compressive strength of concrete, and the spacing of the lateral ties. Finally, the applicability of the design codes, including Eurocode 2, ACI 318–19, and AS 3600 for conventional reinforced concrete columns, to the design of SEARC columns is examined. The results show that the design formulae specified by AS 3600 can be used to calculate the ultimate strength of SEARC columns with reasonable accuracy.

Effectiveness of Lateral Load Resisting Systems for Open Ground+20 Storied RC Framed Structure

Abstract: In a highly populated country like India, problem of parking of the vehicles arises, this problem leaves no option for design of open ground storey buildings. Since there are no infill walls in ground storey, stiffness in the upper storey is much more than the ground storey. The columns in the ground storey are heavily stressed, therefore it is required that the ground storey columns must have sufficient strength and adequate ductility, the increased base shear is resisted entirely by the columns of ground storey only. These buildings are vulnerable due to the sudden lowering of stiffness and strength in the ground storey. This results in the attraction of more earthquake forces for the lower time periods, which also results in snapping of lateral ties in column, crushing of core concrete, buckling of longitudinal bars and finally shear failure in open ground storey columns due to lateral earthquake forces. Solution for this problem is to prevent the failure of open ground storey columns due to lateral earthquake forces by providing the lateral load resisting system. Many times, stiffness of walls is not considered while designing, this results in inaccurate designing of elements. An Open Ground +20 storied RC frame subjected to strong motion earthquakes viz. Duzce in Turkey (12/11/1999), Erzincan in Turkey (13/03/1992), Imperial valley at El-centro (19/05/1940), Landers (28/06/1992) and Nahanni in Canada (23/12/1985) creating soft storey effect at ground storey so it should be provided with lateral load resisting systems viz, Shear wall, steel bracing, lead rubber bearing base isolator with different configurations. Performance of equivalent diagonal strut provided to structure is compared with brick work modelled as actual brick work, equivalent diagonal struts, and considering only the mass of brick work. Time History Analysis is used in a RC framed building using ETABS Version18 and SAP2000 Version20 software in comparison with Response quantities Roof displacement, soft storey check, Base shear, overturning moment and storey drift. In this research, equivalent diagonal struts are provided as brick masonary, which shows accurate behavior of structure under strong ground motions as mass and stiffness both are considered during analysis. When Open ground storied structure is subjected to strong ground motions, stiffness at ground storey is drastically reduced. When structure is assigned with Lateral Load Resisting Systems, shear wall with configuration shear wall at ground storey and 1st storey, stiffness at ground storey is increased to 81% and 82% in X and Y direction respectively within permissible limits. Hence it can be concluded that when there is soft storey effect at open ground, structure becomes hazardous in presence of strong ground motions. When structure is subjected to strong ground motions, the vulnerability condition is high. Since we have performed non-linear dynamic time history analysis, more accurate results can be obtained as non-linear analysis considers vertical irregularities

Residual strength and strengthening capacity of reinforced concrete columns subjected to fire exposure by numerical analysis

AbstractThis study is a numerical investigation of the performance of reinforced concrete (RC) columns after fire exposure. This study aims to investigate the effect of introducing lateral ties and using the RC jacket on improving post-fire behavior of these columns, the effect of the duration of the fire on ultimate load of columns. The analysis was performed through ABAQUS, a 3D – non-linear finite element program. 4 m tall lengthening square RC column with a cross- section of 0.4 m × 0.4 m was used as a test specimen. The RC column was reinforced by 4Ø28 mm longitudinal bars bonded by steel tie bars of Ø10 mm spaced at 400 mm. The firing temperature was increased to 600°C for 60 min. The results indicated that as the fire load duration increases, the load’s capacity diminishes. The effect of increasing the steel ratio of the RC column resulted in a decrease in the percentage of load reduction following combustion. It was concluded that strengthening columns by RC jackets is efficient and that the axial load capacity of reinforced columns was enhanced.

Performance of Concrete Column Using Welded Wire Mesh as Lateral Ties Subjected to Lateral Loading

AbstractThe present study recommends a confining reinforcement mechanism, welded wire mesh (WWM), to enhance the performance of columns during seismic loading. Experimental studies were done on con...

‘I dress in silk and velvet’: women, textiles and the textile-text in 1930s Uzbekistan

ABSTRACT In the 1930s, luxury textiles such as silk and velvet appeared frequently in agitation and propaganda addressed toward women in Uzbekistan. After examining the cultural and material significance of luxury textiles for Central Asian women before collectivization, this article investigates how luxury textiles were used in the effort to mobilize Central Asian women during the years of collectivization and cottonization (c.1929–37). The article concludes with a close reading of several ‘textile-texts’ produced by Central Asian women, focusing particularly on women’s poetry about luxury textiles. The article argues that the discourse of ‘silk and velvet’ tapped into affective resonances rooted in, among other conditions, the local gift economy, Central Asian women’s material conditions, Orientalist discourses and Stakhanovite propaganda. The discourse of silk and velvet thus bolstered hierarchical relations between Central Asian women and the Party–state, while at the same time it generated lateral ties to a public of other Central Asian women. The article relies on research in a variety of archival sources and the Uzbek-language Soviet press, particularly the women’s press.

Influence of restrainer bar chairs on the compression and flexural behaviour of reinforced masonry walls

Lateral restrainers are traditionally provided in reinforced masonry (RM) walls to prevent the vertical steel bars from buckling. In the current version of the Australian Masonry Standards (AS 3700–2018), the use of lateral restrainers in RM walls is relaxed, if the vertical rebars are surrounded by grout annulus of twice the diameter of the bars. However, it is challenging to maintain the verticality of the reinforcing bars in the block cores to satisfy the grout annulus requirement without lateral restrainers. To address this challenge, restrainer bar chairs can be used in the construction of RM walls which are easier to employ in comparison to lateral restrainer ties. However, the implications of adopting restrainer bar chairs as an alternative to restrainer ties in RM wall construction are not well verified. In this study, the influence of restrainer bar chairs and conventional lateral ties restraining methods on the axial compression and out-of-plane bending characteristics of RM walls have been investigated. In total, twelve RM walls of dimensions 1390 mm height × 590 mm length × 190 mm thickness were constructed and tested, of which, four walls each were tested under concentric and eccentric compression and four-point bending. The experimental results revealed that the performance of RM walls with restrainer bar chairs and conventional lateral ties were similar, in terms of the observed failure modes, strength, load–displacement characteristics obtained under both compression and out-of-plane loading conditions. Strain measurements on rebars indicated that a composite action was ensued in both restrainer configurations. The capacities of the RM walls under compression and out-of-plane bending were also verified with three different masonry standards provisions and were found adequate with reasonable safety. Overall, it can be concluded that the restrainer bar chairs can effectively be used in RM walls to enable quick and accurate vertical positioning of the rebars and ensure adequate grout annulus around them.

Improved design provisions for reinforced concrete block masonry walls under axial compression

The provisions pertaining to design of reinforced masonry (RM) walls under axial compression in the Australian masonry standard AS 3700 (2018 version) have been revised based on the recent findings that the lateral restraining ties do not significantly affect the performance under axial compression. The other design codes such as Canadian (CSA S304.1-14), American (MJSC) and previous version of Australian (AS 3700-2011) standards consider the RM walls as unreinforced masonry (URM) under axial compression, if they are not restrained with lateral ties in both directions. However, it is widely believed that these provisions are stringent and over-conservative, as proven by the experimental studies that the compression bars in RM are effectively restrained by the surrounding well compacted grout. Hitherto, no systematic studies have been carried out to determine the applicability of these provisions to the reliability of the compression design approaches of RM walls. Therefore, in this research an attempt has been made to evaluate the accuracy and reliability of the design provisions outlined in the selected design standards (AS 3700, CSA S304.1-14 and MSJC). The experimental database generated in the authors’ previous study was used to verify the reliability of the design provisions. The reliabilities of the design expressions were verified using the first-order reliability method (FORM). The reliability analyses revealed that the provisions specified in the standards are quite conservative as they have exceeded the target reliability index of 3.6 for the analysed RM walls. The current provisions of AS 3700 (2018 version) have shown to predict the axial capacities of the walls better than other standards, while satisfying the target reliability limit. Thus, it can be stated that revisions made in AS 3700 (2018 version) are effective and economical for designing the RM walls as they have eased the requirement of lateral restrainers and account for a realistic contribution of grout and compression steel strengths in determining the axial capacity.

Comparative study of confining reinforcement used for the rectangular concrete short column

Columns play a major role in reinforced concrete building frames. It is observed that one of the cause of the failure is the insufficient confining reinforcement provided in the columns. The transverse reinforcement provided in the columns also plays a crucial role in preventing the failure of the column under critical conditions. Only the lateral ties used in the columns do not provide safety against deformation and damage. Hence, columns need to be strengthened by providing additional material as a means of confining reinforcement. In this research work, a comparative study of rectangular reinforced concrete short columns is presented. The experimental study of ten different column configurations was carried out using confining materials such as welded wire mesh, ferro cement wall panels, glass fiber mesh, nylon polymer mesh, spot welding, combination of welded wire mesh and chicken mesh, additional diagonal ties and stapled stirrups. Each of the ten configurations consists of three sets of M25 grade columns of size 150×230×550mm. The columns were tested under axial compressive load and the test results were compared with respect to ultimate load carrying capacity of the columns, vertical and lateral deformation of the columns, ductility, practical feasibility and the cost of the columns. The test result shows that the ultimate load carrying capacity of the column for all means of confinement was increased from 16.48 % to 89.24%. A significant improvement in ductility was also observed. Columns confined with nylon polymer mesh (NPM) were found to be efficient and economical as compared to other materials used for confinement.

Investigating Optimal Confinement Behaviour of Low-Strength Concrete through Quantitative and Analytical Approaches.

Reinforced concrete is used worldwide in the construction industry. In past eras, extensive research has been conducted and has clearly shown the performance of stress–strain behaviour and ductility design for high-, standard-, and normal-strength concrete (NSC) in axial compression. Limited research has been conducted on the experimental and analytical investigation of low-strength concrete (LSC) confinement behaviour under axial compression and relative ductility. Meanwhile, analytical equations are not investigated experimentally for the confinement behaviour of LSC by transverse reinforcement. The current study experimentally investigates the concrete confinement behaviour under axial compression and relative ductility of NSC and LSC using volumetric transverse reinforcement (VTR), and comparison with several analytical models such as Mander, Kent, and Park, and Saatcioglu. In this study, a total of 44 reinforced-column specimens at a length of 18 in with a cross-section of 7 in × 7 in were used for uniaxial monotonic loading of NSC and LSC. Three columns of each set were confined with 2 in, 4 in, 6 in, and 8 in c/c lateral ties spacing. The experimental results show that the central concrete stresses are significantly affected by decreasing the spacing between the transverse steel. In the case of the LSC, the core stresses are double the central stress of NSC. However, increasing the VTR, the capacity and the ductility of NSC and LSC increases. Reducing the spacing between the ties from 8 in to 2 in center to center can affect the concrete column’s strength by 60% in LSC, but 25% in the NSC. The VTR and the spacing between the ties greatly affected the LSC compared to NSC. It was found that the relative ductility of the confined column samples was almost twice that of the unrestrained column samples. Regarding different models, the Manders model best represents the performance before the ultimate strength, whereas Kent and Park represents post-peak behaviour.

Cyclic behaviour of precast reinforced concrete beam-columns connected with headed bars

This paper evaluates the structural behaviour of precast reinforced concrete (RC) beam-columns connected with novel ribbed headed bars, and compares with conventional anchorage system of development length and partial development length. Additionally, the effect of encasement with expa-mesh and varying spacing of lateral ties in precast RC column is also investigated. Precast RC beam-column joints were subjected to the displacement controlled quasi-static reversed cyclic loading on the beam end and constant axial load on the column. Structural behaviour was assessed with regards to damage pattern, cyclic load capacity, stiffness degradation, deformation characteristics and energy dissipation; and performance assessment carried out in accordance with ACI 374.1–05. Most of the specimens experienced crack at the interface of beam-column joint at yield limit. Ultimate failure was beam rebar rupture along with separation of beam and column, thus forming plastic hinge at the joint, rather than in the beam element. Both headed bar and conventional specimens surpassed their nominal moment strength and design shear force, thus exhibiting satisfactory performance. On the other hand, specimens with partial development length attained their nominal moment strength but failed to reach joint shear. The strength parameters of headed bar specimens were well comparable to that of conventionally detailed specimens and satisfied the acceptance criteria of ACI 374.1–05, which can be considered as a benchmark to adopt the proposed ribbed headed bar system of anchorage for precast RC beam-column joints in light of its certain advantages over conventional anchorage system.

Stress–strain model for high-strength concrete tied columns under concentric compression

Providing accurate constitutive stress–strain relationships for confined concrete can increase the reliability of the moment curvature (MC) analyses in the displacement-based seismic design of reinforced concrete (RC) columns. This paper presents a new stress–strain model for high-strength concrete (HSC) tied square columns which exhibit a more brittle behavior than normal strength concrete (NSC) members. Introducing the concept of least confined volume in the damage localization zone at the middle of the concrete core, a new approach is developed for the confinement stress distribution of lateral ties. In order to determine the lateral stresses acting on the vertical surfaces of the least confined volume, the effective confinement stresses are reduced considering the tie configuration. The peak strength and the ductility of the column should therefore be calculated for the confined concrete in this region. A concrete failure criterion applicable to multi-axial compression due to the reduced confinement stresses in two orthogonal directions, is then used to determine the ultimate strength of HSC columns. Moreover, plotting the compression meridian of the failure criterion, a simple and design-oriented formula is proposed for the ultimate strength of HSC tied columns. The validity of the proposed approach and the performances of two well-known analytical models are verified against the test results of eighty-six HSC columns from five different experimental studies for both the axial stress–strain behavior and the ultimate strength. Besides, the implementation of the concept of the reduced confinement stress in the Mander’s model leads to a significant improvement in its capability of predicting the triaxial strength of HSC.

Strengthening of compression member by ferrocement with high performance mortar – Jacketing technique

External strengthening using Jacketing technique can suitably use for increasing the Axial and shear strength of RC square Column [1] . This paper includes an experimental investigation for studying the effectiveness and suitability of high performance ferrocement mortar mixes as a retrofitting material and its use as jacket for square columns. The experimental programme included development of high performance ferrocement mortar mix by adding 10% of silica fumes and 1% of super plasticiser and its use in retrofitting of square column specimens which were either intact or distressed earlier to certain level [2] . The experimental programme consisted of testing 2 controlled specimens and 6 retrofitted specimens initially distressed to 80–85% of theoretical stress level, repairing, and retrofitting prior to testing. The control specimens were of dimension 100mmx100mm and 500 mm height, cast in M30 conventionally vibrated concrete, reinforced longitudinally with four bars of 8 mm diameter and six lateral ties of 6 mm diameter as transverse reinforcement [3] . Three different mixes proportions of 1:1.5, 1:2, 1:3, were used for jacketing around the columns. The jacket was reinforced with mild steel welded wire mesh 50 mm × 50 mm made of 1.16 mm diameter wire. The retrofitted specimens were tested after 28 days of curing. Carbon Fibre Reinforced Polymer (CFRP) Sheet is provided at top and bottom of the specimens. And then the results are compared at the end the Retrofitted specimen of 1:1.5 Ferrocement mix has more Load carrying capacity than other Ferrocement mix when compared with controlled of 8.85%.

Investigation of Confinement Effects for Determining Moment Curvature and Interaction Diagram of Reinforced Concrete Column

This paper presents the relevance of using various material models to represent the inherent material non-linearity of the cross-section in generating moment curvature relationship. Further, confinement effects are imposed on geometry and P-M diagram is constructed of typical cross-section of column adopted in Nepal. Also, the modelling capability and user defined modelling aspects in terms of section, material behavior is assessed and suitability of modelling criteria to depict the actual displacement capacity is studied. It was observed the ultimate curvature of the un-confined concrete section considered was obtained approximately to be 0.16 per m while for studied confined material models the curvature was obtained approximately to be 0.66 per m. This increase in curvature is due to the confinement effect of the lateral ties. It was observed that the loss of strength of concrete in cover is compensated by use of the confinement since gain in axial and bending capacity of the confined concrete in comparison to unconfined one in compression control region. Hence, it is suggested to adopt the confined material model as user-defined for generating hinge property for non-linear analysis of the structures.