Angle Shear Connectors Research Articles

EVALUATING THE STRUCTURAL EFFICACY OF ANGLE AND CHANNEL SHEAR CONNECTORS IN BRICK AGGREGATE CONCRETE AND STONE AGGREGATE CONCRETE AND COMPARISON

Composite structure is becoming prominent for its economy, less time consumption, and higher stiffness-mass ratio. Composite action of the steel-concrete composite structure mainly depends on the connector's geometry and materials. Proper choice of shear connector could make steel beam and concrete slab cross-section minimal. This study carries out push-out tests to evaluate the structural efficiency of channel and angle shear connectors in brick aggregate concrete and stone aggregate concrete. It specifically looks at the failure mode, ductility, load-slip behavior, and energy absorption capacity. In brick aggregate concrete, results show that under monotonic loading, channel connectors have been found to have 15.27% more shear capacity & 28.38% more slip than angle connectors. Similarly, in stone aggregate concrete, channel connectors have been found to have 14% more shear capacity & 12.97% higher slip than angle connectors. On average, stone aggregate concrete has been found to have 34.84% higher shear capacity and 6.7% greater slip than brick aggregate concrete. Strain energy and plastic energy were found 78% and 17.6% less in brick aggregate specimens than those in stone aggregate specimens, respectively. Experimental results were slightly lower for both shear connectors than the empirical values.

Pushout tests on demountable bolted angle shear connectors for steel-concrete composite structures

Welded connectors are commonly utilized in steel-concrete composite construction. However, these connectors lack demountability, hindering the recycling or reuse of steel sections. In response to this limitation, high-strength bolts have been proposed as alternatives to traditional welded shear connectors to facilitate demountability. Nevertheless, the use of numerous high-strength bolts may negatively impact construction costs due to their limited capacity. This paper introduces a novel solution: the bolted angle shear connector. Comprising a standard angle section, a smaller size angle section functioning as a hat, and a high-strength bolt, this connector aims to balance the demountability advantage while avoiding the drawbacks associated with high-strength bolts. To assess its performance, the proposed connector was embedded into a solid concrete block, and horizontal pushout tests were conducted on 31 specimens. Variables considered included the angle section size, bolt diameter, bolt grade, concrete compressive strength, loading direction, and bolt thread condition. The findings reveal that the proposed connectors demonstrate a ductile response, meeting the mandated slip capacity of at least 6 mm according to EN 1994–1-1. Two distinct failure modes were observed: bolt fracture and a combination of concrete crushing and angle bending. The shear resistances at 6 mm slip ranged from 146 kN to 280 kN, influenced by the angle size and concrete compressive strength. Capacities were formulated as functions of these variables, leading to the development of design recommendations, which are presented in this paper.

Failure investigation of steel and brick aggregate concrete composite construction with angle and channel shear connectors

ABSTRACT This investigation focuses mainly on the failure behaviour and performance of angle and channel shear connectors in composite structures made with steel and brick aggregate concrete. It was observed that both angle and channel shear connectors did not fail themselves. However, in some specimens, localised connector yielding was observed in channel shear connectors. In both cases, concrete strata failed as either concrete crushing and shearing, combined splitting and bending, or complete splitting mode of failure. Crushing and shearing failure was noticed in specimens having smaller web and flange and were brittle in nature as compared to the failure of specimens with larger web and flange. Other parameters, such as shear resistance, energy absorption, and load-slip behaviour, were also investigated. Web height and flange width of both connectors significantly affected the ultimate shear capacity and slip of the brick aggregate concrete specimen. Channel connectors were found more flexible and carried more shear than angle connectors. Channel connectors had an average of 32.41% and 116.17% more ultimate load and slip capacity than the angle connectors in brick aggregate concrete, respectively. The load-carrying capacity, slip, and failure behaviour of the brick aggregate concrete were found similar to those of stone aggregate concrete.

Performance of angle shear connectors for U-shaped steel concrete infilled composite beams

The current design codes i.e. AISC 360-16, CSA-S16-19, EC-04 etc. provide empirical relationships to estimate the capacity of shear connectors which were developed based on pushout tests of headed studs and channels connectors in exposed type sections. Therefore, these equations may result inaccurate predictions for strength of connectors in infilled-type sections. This study presents a detailed experimental study investigating the performance of angle connectors in composite sections. The testing program consisted two series of pushout tests. A total of 36 specimens were tested, considering the influence of several important parameters i.e. the length (Lc), height (hc), and web-thickness (tw) of angle connector, length of the weld (w) and the direction of shear connector (forward/backward) etc. The tests results demonstrated that with increasing connector height hs, and thickness, the maximum load Pmax and slip δu were increased. The connector direction didn’t change much the load-slip behavior. The prediction accuracy of the existing shear capacity models was evaluated by comparing the predictions with experimental results. The current equations were noticed to be highly inconsistent in predicting the shear capacity of angle connectors, especially in case of infilled type sections. When the entire length of connector was taken as the effective length, the models overestimated the shear capacity. While in case when the welding length was taken as effective length in calculations, the models underestimated the shear strength of angle connectors.

Angle shear connectors: Pushout tests, numerical simulations and shear strength model

Despite several advantages i.e. ease in fabrication and installation, economic design, higher structural performance etc., the use of angle shear connector has been limited thus far. This is because, there exists no design equation for this connector type in the design standards. Currently, these connectors are designed through the equations originally developed for other connectors. In this study, the performance of angle shear connectors was investigated through experiments and numerical simulations. The experimental results revealed that the connector height influences the performance which is currently ignored in most of the design code equations for channel connectors. The influence of wide range of other parameters was studied through numerical simulations. A parametric study was conducted considering the effect of angle length, height, thickness, welding length, and strength of concrete. Finally, a theoretical model, capable of predicting the strength of angle shear connectors, was developed and verified against experimental results of this study and others from previous literature.

Flexural Behavior of Composite Beams with Angle Shear Connectors

Flexural Behavior of Composite Beams with Angle Shear Connectors

Experimental and analytical investigation of notched steel plate as a novel shear connector

To ensure durability and save time in construction, steel–concrete composite slabs are widely used in aging bridge replacement. This paper proposes a novel type of shear connector named notched steel plate (NSP). The shear properties of four types of NSP shear connectors with heights of 50 mm and 75 mm and thickness values of 9 mm and 12 mm were evaluated by conducting push-out tests. Concrete cracks occurred firstly during the loading. After removing the concrete block, fracture of NSP shear connectors at the welding zone between NSP and steel plate was observed. A finite-element (FE) analysis was conducted considering the nonlinear properties of materials and interface between the NSP and concrete block. The shear stiffness, shear capacity and failure pattern obtained using the FE model matched with the test data. The verified FE model was used to investigate the failure mechanism of NSP and to clarify the effect of the constraint force, concrete compressive strength and steel strength on the NSP shear capacity. The experimental shear capacity values were compared with the values calculated by the specifications for channel and angle shear connectors. The results of the NSP shear capacity were similar to those obtained based on the American Institute of Steel Construction (AISC) specifications and Eurocode 4.

Flexural behavior of large-scale U-shaped steel-concrete infilled composite beams with flat and embossed webs

Most popular shape of steel-composite beams is the exposed type in which wide-flange steel sections are connected to the reinforced concrete (RC) slab through shear connectors. However, recently innovative U-shaped steel–concrete infilled type composite beam sections are introduced which demonstrated promising structural performance. In these composite beams, the U-shaped steel section filled with concrete serves as formwork in fresh state of concrete while it behaves as main reinforcement during the service life of the structures. Although, active research has been conducted on former type, but research on the later infilled type beams seems insufficient. There exist several research questions which need to be addressed for optimized and efficient design of these innovative composite sections. In this paper, six large-scale U-shaped steel–concrete infilled composite beams with flat and embossed webs were tested to investigate their flexural behavior. The tested composite beams were designed with angle shear connectors which provide efficient shear transfer mechanism with economy. The main parameters of the tests were the shape of web and the spacing of the shear connectors. The effects of embossed web on horizontal shear transfer and its contribution to the flexural capacity were mainly focused. In addition, a detailed section analysis was conducted to comprehend the experimental observations.

Analytical Assessment of the Structural Behavior of a Specific Composite Floor System at Elevated Temperatures Using a Newly Developed Hybrid Intelligence Method

The aim of this paper is to study the performance of a composite floor system at different heat stages using artificial intelligence to derive a sustainable design and to select the most critical factors for a sustainable floor system at elevated temperatures. In a composite floor system, load bearing is due to composite action between steel and concrete materials which is achieved by using shear connectors. Although shear connectors play an important role in the performance of a composite floor system by transferring shear force from the concrete to the steel profile, if the composite floor system is exposed to high temperature conditions excessive deformations may reduce the shear-bearing capacity of the composite floor system. Therefore, in this paper, the slip response of angle shear connectors is evaluated by using artificial intelligence techniques to determine the performance of a composite floor system during high temperatures. Accordingly, authenticated experimental data on monotonic loading of a composite steel-concrete floor system in different heat stages were employed for analytical assessment. Moreover, an artificial neural network was developed with a fuzzy system (ANFIS) optimized by using a genetic algorithm (GA) and particle swarm optimization (PSO), namely the ANFIS-PSO-GA (ANPG) method. In addition, the results of the ANPG method were compared with those of an extreme learning machine (ELM) method and a radial basis function network (RBFN) method. The mechanical and geometrical properties of the shear connectors and the temperatures were included in the dataset. Based on the results, although the behavior of the composite floor system was accurately predicted by the three methods, the RBFN and ANPG methods represented the most accurate values for split-tensile load and slip prediction, respectively. Based on the numerical results, since the slip response had a rational relationship with the load and geometrical parameters, it was dramatically predictable. In addition, slip response and temperature were determined as the most critical factors affecting the shear-bearing capacity of the composite floor system at elevated temperatures.

Structural Performance of Channel and Angle Shear Connectors in Brick Aggregate Concrete

This study is based on the necessity of sustainable housing in earthquake-prone and wind-prone coastal locations. It focuses on determining the load-slip behavior, failure mode, and ductility of low-strength concrete made with brick aggregate containing channel and angle shear connectors fixed with the wide flanged beam. Under monotonic loading, channel connectors have an average of 15.11% and 54.81% higher shear capacity and slip than angle connectors in brick aggregate concrete slab. Shear loads from experiments are compared with some formulas. It is found that formulas give slightly higher results than experimental results for both channel and angle shear connectors of the brick aggregate concrete.

Finite Element Analysis of Novel Stiffened Angle Shear Connectors at Ambient and Elevated Temperature

This is a numerical study to investigate the behavior of novel stiffened angle shear connectors embedded in solid concrete slabs at both ambient and elevated temperatures. An advanced nonlinear finite element model is developed and validated with available experimental work by Nouri, K., et al. 2021. Additionally, parametric studies are performed to evaluate the variations in concrete strength and the connector’s dimensions. The results indicate that the ultimate strength of the stiffened angle shear connector drops by 92% in 1050 °C. Comparing studies show the strength of the stiffened shear connector at 700–850 °C is equivalent to the ordinary C-shaped shear connectors. The stiffened shear connector is more ductile at elevated temperatures as compared to ambient temperatures. The shear strength raised to 66% and 159.7% by increasing the height and width of the stiffened shear connector, respectively. Furthermore, the height of the stiffened shear connector is crucial to enhance the shear strength capacity as compared to the ordinary C-shaped shear connector.

Structural performance of novel aluminium alloy gusset joints for connecting four I-section beam members

This paper presents the seismic behaviour of an aluminium alloy grid shell structure with due consideration of the rotation performance of its two novel gusset joints. The two novel aluminium alloy gusset joints were designed for connecting cross-arranged I-section beam members by stainless steel swage-locking pins and stainless steel bolts. One full-scale gusset joint was tested under monotonic loading, with the failure mode, load-displacement response and stiffness classification fully reported. The solid-based refined finite element (FE) model of the joint was developed by using Abaqus program and validated against test results. Based on the validated FE model, parametric studies were performed to investigate the effect of key parameters, including the shape of gusset plates, the preload of fasteners, angle shear connector configurations, and the number and layout of pins, on the structural performance of the novel gusset joints. The failure modes, moment-rotation curves, initial stiffness and ultimate design resistance were identified and compared in groups for joint design optimization. The cyclic behaviour of two optimal gusset joints was numerically analysed, and then incorporated in the fibre-based macro FE model of the aluminium alloy grid shell structure developed by using OpenSees program. The seismic performance of the grid shell structure subjected to different earthquake hazard levels, including the displacement, joint rotation, beam stress and shear base responses, was comprehensively evaluated. Sound earthquake resistance of the aluminium alloy grid shell structure is demonstrated, with safety and reliability of the novel gusset joints used in it.

Parametric investigations on shear behavior of perforated transverse angle connectors in steel–concrete composite bridges

The perforated transverse angle connectors (PTACs), that posses excellent shear capacity and good ductility, have been proposed to address the casting obstruction of the bottom concrete decks in prestressed composite (PC) box-girder with corrugated steel webs (CSPWs). The structural performance of steel–concrete composite bridges largely depends on the behavior of the mechanical shear connectors. In this study, numerical analyses on the shear behavior of the PTAC were performed. The finite element (FE) model was developed using ABAQUS and validated by comparing its predictions with test data available in the literature. The comparisons indicated that the numerical model could reflect the experimental results closely. Parametric studies were then carried out to determine the influential factors on the PTAC shear capacity. It was found that the shear strength of the PTAC increased linearly with the increase of the concrete strength. The flange and web thickness had great effect on the PTAC shear capacity, while the flange and web height slightly influenced. The group PTAC arrangement had a significant influence on the shear strength and this effect can be ignored when the spacing was more than 400 mm. In addition, the perforating rebar contributed little to the shear capacity but obviously enhanced the ductility. The FE analysis results were used to verify the applicability of the current design provisions for the PTAC shear strength. It was noted that the formulas in these provisions conservatively predict the shear strength due to the effect of the flange welded on the steel girder was ignored. An empirical formula was developed to evaluate the shear strength of angle shear connectors. The mean of the ratio of the predicted results to test ones ranged from 0.981 to 1.018, which denoted the proposed design formula could accurately be used to predict the PTAC shear capacity.

Shear resistance of embedded connection of composite girder with corrugated steel web

Embedded shear connection with reinforced concrete dowels between corrugated steel webs and concrete flanges is emerging as an alternate connection type to conventional headed studs, perfobond, channel, angle shear connectors, owing to its inherent advantages, such as ease of installation, economical, efficient and better fatigue resistance. In present study, experimental investigations are carried out to understand the influence of embedment depth, concrete dowel with or without reinforcement, area of dowel bar reinforcements on shear resistance of composite system with corrugated steel web and concrete flanges using push-out tests. Totally six push-out specimens are cast by varying (i) depth of embedment, (ii) concrete dowel with and without reinforcement and (iii) area of dowel reinforcement. From the experimental investigations, it is observed that the increase in depth of embedment of web increases the load carrying capacity whereas increase in area of the dowel bar reinforcement increases load as well as slip. It is also observed that the embedded shear connection with concrete dowels showed enormous slip before failure and hence could be classified as ductile shear connector according to EN-1994-1-1. The experimental results are used to establish the influence of different parameters on shear resistance and also used to identify different means that contribute to the shear resistance of embedded shear connection. Further, multiple linear regression analysis is carried out on the data of present study and results reported in the literature to arrive at an expression for most reliable estimate of shear resistance of embedded shear connection for composite girder with corrugated steel web.

Hybridization of metaheuristic algorithms with adaptive neuro-fuzzy inference system to predict load-slip behavior of angle shear connectors at elevated temperatures

Steel-Concrete Composite floor systems are one of the essential components in the construction industry. Recent studies have shown that fire-induced problems damage shear connectors and change the behavior of composite systems. To predict the performance of connectors, experimental tests are generally conducted at elevated temperatures or fire conditions. However, these tests need plenty of time, cost, and effort. This paper aims to propose a soft computing (SC) approach to predict the behavior of angle shear connectors at elevated temperatures. For this purpose, an adaptive neuro-fuzzy inference system (ANFIS), a particle swarm optimization (PSO) algorithm, and a genetic algorithm (GA) are hybridized and a novel ANFIS-PSO-GA model is proposed. To evaluate the performance of the ANFIS-PSO-GA model, a radial basis function network (RBFN) along with an extreme learning machine (ELM) are also developed. Finally, the performance of the ANFIS-PSO-GA, RBFN, and ELM are compared in the terms of different statistical indicators. The results of the paper show that the SC approach is applicable in the behavior prediction of angle connectors at elevated temperatures. Besides, it was concluded that the ANFIS-PSO-GA model can provide better estimations of load and slip in comparison with those of RBFN and ELM models.

Experimental investigation on shear performance of transverse angle shear connectors

To overcome the concrete casting obstruction of the bottom slabs in prestressed concrete box-girders with corrugated steel webs (CSWs), transverse angle shear connectors were adopted in some cases. The overall behavior of such steel–concrete structures highly depended on the shear behavior of the connectors. Seven large-scale push-out specimens, with different height and spacing of shear connectors, were tested to examine the shear performance of transverse angle shear connectors. The failure modes, load-slip relationships, ultimate shear strengths, initial stiffness and ductility of specimens were explored. Based on the experimental results, this study suggests that both of the connector height and spacing impacted the shear strength of transverse angle connectors. The initial stiffness of specimens improved with the increasing of both connector height and number. The ductile characteristic can also be observed in the load-slip relationship. Compared with traditional longitudinal PBL shear connector, the transverse angle shear connectors also showed apparent strength enhancement and acceptable ductile characteristic. The equation for angle shear connectors suggested in Eurocode 4 can be used for predicting the shear strength of transverse angle shear connectors with spacing ranged from 350 mm to 450 mm.

Experimental and Theoretical Study on Shear Stiffness of Angle Shear Connectors

Experimental and Theoretical Study on Shear Stiffness of Angle Shear Connectors

Structural performance of steel angle shear connectors with different orientation

This paper presents a study of angle shear connectors with two types of orientations. Shear connectors are used to transfer shear forces through the steel–concrete. In Ecuador constructors make buildings using different types of shear connectors and most of them have not been studied. Indeed, using angles is cheaper than studs and channels. In this study, fourteen composite specimens containing steel angle shear connectors were prepared to determine the full capacity of those angles. The angles were set in 45° and 90° orientation. Monotonic, cyclic load, and push out loading tests were applied, and shear strength, ductility, failure modes and stiffness were discussed. Comparing the two groups it was concluded that Group A (45°) presents less scatter than Group B (90°). In both groups, first cracks appeared when samples reach 50 % of the expected failure load and became greater and longer about 80 %, and all samples experienced failure of the connector. Group A specimens had a better behavior in terms of the ultimate shear capacity and satisfied ductility criteria given by Eurocode. Group B specimens presented similar results to Group A, but with a larger scatter. Finally, shear capacities from tests are compared with some code formulas, using an analogy, and it is found that codes give slightly lower results.

Experimental and numerical investigations of composite concrete steel flexural members with angle shear connectors under negative moment

Experimental and numerical research has been conducted to investigate the role of using angle shear connectors as a replacement of headed stud (HS) on the performance of the composite beams under the effect of the negative bending moment (NBM). The replacement was done by using the same cross-section area for both connectors. A total of five specimens were fabricated and tested under the effect of NBM. Shear connector type, bond interaction (partial and full), and angle shear connectors arrangement were considered as the main parameters. A finite element model (FEM) was built using commercial software for modeling the composite beams. The experimental results, the ultimate strength decreased by 4.12% for single angle shear connectors, compared to the specimens with HS shear connectors. The numerical results showed a good agreement with the experimental results in terms of load-displacement relation and mode of failure.

Analyzing shear strength of steel-concrete composite beam with angle connectors at elevated temperature using finite element method

Steel- concrete composite beams are widely used in the construction of tall building with steel floors. In these floors, the bearing capacity of beams in which the performance of concrete and steel is composite is more than 30% of the same beams with non-composite performance. Fire, especially in buildings, has a devastating effect on the components of the structure including the columns, beams, floors, etc. Also, fire indirectly affects the shear connectors buried in floor concrete and reduces their strength, thus reducing the overall strength of the floor. In this research, the behavior of angle shear connectors as a type of shear connectors used in the steel-concrete composite floor due to temperature increase was investigated numerically. Thermo-mechanical finite element modeling was performed using Abaqus software on push-out samples, and the results have been compared with the results obtained from the laboratory tests. Similar to the laboratory conditions, samples with different dimensions of angle shear connectors were modeled at different temperatures including 25, 550, 700 and 850 degrees Celsius. According to the laboratory process, 24 samples were modeled in Abaqus software thermally. The research results showed that the models made in the software were able to accurately predict the laboratory results including shear strength and slip. It was found that the maximum shear force error between analytical and laboratory results is 21.6% and the minimum shear force error in some samples is near to zero. As the temperature increases, the error rate between the laboratory and analytical results increases. Also, shear connector dimensions, concrete strength and temperature value have direct effect on the final strength of steel-concrete composite floors and load slip diagrams. It was also concluded that increasing the angle height to a certain extent could increase the final shear strength of the steel-concrete floor and increasing the angle height after a certain limit had no effect on increasing the shear strength and results in material loss and uneconomical design. Moreover, results indicated that increasing the temperature up to 850C leads to reducing the shear strength of the samples by approximately 56%.