Size effect on the shear capacity of headed studs

2020 ◽  
pp. 136943322096903
Author(s):  
Ahmet Abdullah Dönmez
Keyword(s):  
Size Effect ◽  
Failure Modes ◽  
Three Dimensional ◽  
High Strength ◽  
Shear Capacity ◽  
Microplane Model ◽  
Effect Factor ◽  
Shear Connectors ◽  
Concrete Damage ◽  
Damage Constitutive Model

This study aimed to reveal the existence of size effect on the shear connectors used in the steel-concrete composite beams and slabs. The experimental study contains the monotonic tests of nine pushout specimens with the headed studs. Three-dimensional scaling was used for geometrically similar specimens of three sizes. High strength concrete slabs were used on both sides of the steel I-beam. The failure modes of the specimens include both concrete crushing and stud yielding. Finite element (FE) verification of the specimens was conducted using a realistic concrete damage constitutive model, Microplane Model M7. It is shown that there may be a non-negligible size effect based on the fracture patterns of the composite member. Bažant’s size effect law (SEL) can fit the size effect behavior of the shear connectors. The design equations which do not include a size effect term have high correction factors that overestimate the tested specimens. A new design equation can be drawn using the size effect factor for strength reduction of shear connectors.

scholarly journals Compressive behaviours of octet-truss lattices

2020 ◽  
Vol 234 (16) ◽  
pp. 3257-3269 ◽  
Author(s):  
Yifan Li ◽  
Huaiyuan Gu ◽  
Martyn Pavier ◽  
Harry Coules
Keyword(s):  
Failure Modes ◽  
Density Ratio ◽  
Three Dimensional ◽  
Compressive Load ◽  
High Strength ◽  
Detailed Comparison ◽  
Compressive Response ◽  
Beam Elements ◽  
Structural Applications ◽  
Octet Truss

Octet-truss lattice structures can be used for lightweight structural applications due to their high strength-to-density ratio. In this research, octet-truss lattice specimens were fabricated by stereolithography additive manufacturing with a photopolymer resin. The mechanical properties of this structure have been examined in three orthogonal orientations under the compressive load. Detailed comparison and description were carried out on deformation mechanisms and failure modes in different lattice orientations. Finite element models using both beam elements and three-dimensional solid elements were used to simulate the compressive response of this structure. Both the load reaction and collapse modes obtained in simulations were compared with test results. Our results indicate that three-dimensional continuum element models are required to accurately capture the behaviour of real trusses, taking into account the effects of finite-sized beams and joints.

scholarly journals Static Strength of Friction-Type High-Strength Bolted T-Stub Connections under Shear and Compression

2020 ◽  
Vol 10 (10) ◽  
pp. 3600 ◽  
Author(s):  
Gangnian Xu ◽  
Youzhi Wang ◽  
Yefeng Du ◽  
Wenshuai Zhao ◽  
Laiyong Wang
Keyword(s):  
Friction Coefficient ◽  
Ultimate Strength ◽  
Compression Ratio ◽  
Failure Modes ◽  
Load Condition ◽  
High Strength ◽  
Shear Capacity ◽  
Displacement Curve ◽  
Clamping Force ◽  
Bolt Diameter

The friction-type high-strength bolted (FHSB) T-stub connection has been widely used in steel structures, due to their good fatigue resistance and ease of installation. While the current studies on FHSB T-stub connections mainly focus on the structural behaviors under both shear and tensile force, no research has been reported on the mechanical responses of the connections under the combined effects of shear and compression. To make up for this gap, this paper presents a novel FHSB T-stub connection, which is simple in structure, definite in load condition, and easy to construct. Static load tests were carried out on 21 specimens under different shear–compression ratios, and the finite-element (FE) models were created for each specimen. The failure modes, initial friction loads and ultimate strengths of the specimens were compared in details. Then, 144 FE models were adopted to analyze the effects of the friction coefficient, shear–compression ratio, bolt diameter and clamping force on the initial friction load and ultimate strength. The results showed that the FHSB T-stub connection under shear and compression mainly suffers from bolt shearing failure. The load–displacement curve generally covers the elastic, yield, hardening and failure stage. If the shear–compression ratio is small and the friction coefficient is large, its curve only contains the elastic and failure stage. The friction coefficient and shear–compression ratio have great impacts on the initial friction load and ultimate strength. For every 1 mm increase in bolt diameter, the initial friction load increased by about 10%, while the ultimate strength increased by about 8.5%. For each 10% increase/decrease of the design clamping force, the initial friction load decreases/increases by 7.8%, while the ultimate load remains basically the same. The proposed formula of shear capacity and self-lock angles of FHSB T-stub connection can be applied to the design of CSS-enhanced prestressed concrete continuous box girder bridges (PSC-CBGBs) and diagonal bracing.

scholarly journals Failure Modes and Resistance of Perforated Steel Rib Shear Connectors under Uplift Forces

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Xiaoqing Xu ◽  
Yuqing Liu
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Analytical Models ◽  
Shear Connectors ◽  
Steel Bar ◽  
Concrete Damage ◽  
Uplift Resistance ◽  
Transverse Steel ◽  
Uplift Forces

In recent years, there is a rapid increase in the application of perforated steel rib shear connectors in steel and concrete composite structures. The connectors must not only ensure shear transfer but also sufficient uplift resistance. The shear behavior of connectors has been extensively investigated. However, studies on uplift resistance are lacking so far. Therefore, three push-out test specimens were tested to investigate the shear and tension behavior of perforated L-shaped and plain steel rib shear connectors. The failure modes of connectors were analyzed, and analytical models for the determination of uplift resistance were derived based on test results. The results showed that the ductility of perforated steel rib shear connectors under uplift force was smaller than that under shear force, and more severe concrete damage surrounding the rib and larger bending deformation of transverse steel bar was observed. The rib flange of L-shaped perforated rib has a significant contribution to the uplift resistance. It was suggested to increase the rib height of L-shaped rib to avoid the horizontal crack at the height of the rib flange. The validity of the proposed analytical models was confirmed by comparing the failure modes and capacities of specimens.

Analysis of seismic performance and research of load capacity of steel reinforced high strength concrete columns with rectangular helical hoops

2020 ◽  
pp. 136943322098165
Author(s):  
Jianyang Xue ◽  
Xin Zhang ◽  
Xiaojun Ke
Keyword(s):  
Failure Mode ◽  
Seismic Performance ◽  
Calculation Method ◽  
High Strength Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
High Strength ◽  
Shear Capacity ◽  
Strength Concrete ◽  
Shear Span

This paper mainly focused on the seismic performance and shear calculation method of steel reinforced high-strength concrete (SRHC) columns with rectangular helical hoops. An experimental investigation was performed in this paper. Eleven SRHC columns with rectangular helical hoops and one with ordinary hoops were constructed at the laboratory of Guangxi university. The failure modes, hysteresis loops, envelope curves, characteristic loads and displacements and cumulative damage analysis are presented and investigated. It can be seen from the test results that the failure modes of SRHC columns can be divided into three types with the shear span ratio increased, namely, shear baroclinic failure mode, flexure-shear failure mode and flexure failure mode. In addition, the specimens with rectangular helical hoops have plumper hysteretic loops. Shear span ratio is the main influencing factor of characteristic load; the axial compression ratio and concrete strength have less influence on characteristic load, while stirrup ratio has little effect on the characteristic load. Finally, a calculation method for shear capacity of SRHC columns under shear baroclinic failure and flexure-shear failure mode is proposed.

scholarly journals Nonlinear numerical simulation of punching shear behaviour of reinforced concrete flat slabs with shear-heads

2019 ◽  
Author(s):  
D.V. Bompa ◽  
A.Y. Elghazouli
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Numerical Models ◽  
Three Dimensional ◽  
Structural Response ◽  
Analytical Models ◽  
Shear Behaviour ◽  
Flat Slabs ◽  
Modes Of Failure ◽  
Concrete Damage

This paper examines the structural response of reinforced concrete flat slabs, provided with fully-embedded shear-heads, through detailed three-dimensional nonlinear numerical simulations and parametric assessments using concrete damage plasticity models. Validations of the adopted nonlinear finite element procedures are carried out against experimental results from three test series. After gaining confidence in the ability of the numerical models to predict closely the full inelastic response and failure modes, numerical investigations are carried out in order to examine the influence of key material and geometric parameters. The results of these numerical assessments enable the identification of three modes of failure as a function of the interaction between the shear-head and surrounding concrete. Based on the findings, coupled with results from previous studies, analytical models are proposed for predicting the rotational response as well as the ultimate strength of such slab systems. Practical recommendations are also provided for the design of shear-heads in RC slabs, including the embedment length and section size. The analytical expressions proposed in this paper, based on a wide-ranging parametric assessment, are shown to offer a more reliable design approach in comparison with existing methods for all types of shear-heads, and are suitable for direct practical application.

scholarly journals Finite element analysis of bolt shear connection of steel-concrete composite structure

2020 ◽  
Vol 198 ◽  
pp. 01027
Author(s):  
Zhishun Pan
Keyword(s):  
Finite Element ◽  
Composite Structure ◽  
Composite Structures ◽  
Mechanical Performance ◽  
Concrete Strength ◽  
High Strength ◽  
Shear Capacity ◽  
Simulation Software ◽  
Element Analysis ◽  
Shear Connectors

Bolted shear connectors are an important component to ensure that steel-concrete composite structures can work together. High-strength bolt shear connectors can replace traditional stud connectors because of their disassembly, good mechanical performance and fatigue resistance. It applied to steel-concrete composite structure. In order to study the influencing factors of the bearing capacity of high-strength bolted shear connectors, this paper uses ABAQUS finite element simulation software as a research tool to establish a reasonable finite element model to study the influence of bolt strength, bolt diameter and concrete strength on bolted shear connectors. Studies have shown that increasing the diameter, strength, and concrete strength of bolted connections can effectively increase the bolt’s shear capacity.

scholarly journals Study on Shear Behavior of Multi-Bolt Connectors for Prefabricated Steel–Concrete Composite Beams

2021 ◽  
Vol 8 ◽  
Author(s):  
Wei Wang ◽  
Xie-dong Zhang ◽  
Xi-long Zhou ◽  
Lin Wu ◽  
Hao-jie Zhu
Keyword(s):  
Mechanical Performance ◽  
Concrete Strength ◽  
Three Dimensional ◽  
Shear Stiffness ◽  
Element Model ◽  
Composite Beams ◽  
Shear Capacity ◽  
Construction Time ◽  
Shear Connectors ◽  
Shear Performance

Multi-bolt shear connectors (MBSCs), arranging bolts as a group in several rows, can be applied in prefabricated steel–concrete composite beams or bridges (SCCBs) to reduce the construction time and meet the requirements of sustainable development. The mechanical behavior of bolt shear connectors has been broadly investigated in recent years, but they were mainly focused on the normal arrangement. The shear performance of MBSCs is not consistent with that of the same number of single bolts. In this study, a three-dimensional (3D) finite element model (FEM) was developed to investigate the multiple bolts effect and its mechanical performance. Material non-linearities and the interactions among all components were included in the FEM. The accuracy and reliability of the proposed FEM were initially verified against the available push-out test results. The validated FEM further studied the load–slip relationship, shear capacity, and shear stiffness of the MBSCs. A parametric study was carried out to determine the effect of the bolt spacing, bolt row numbers, the concrete strength, and the bolt diameter on the shear performance of MBSCs. Based on the extensive parametric analyses, design recommendations considering the multiple bolts effect for predicting the shear resistance per bolt in multi-bolt connectors were proposed and verified.

Failure Mode Attribution Analysis of PBL Shear Connector

2013 ◽  
Vol 351-352 ◽  
pp. 683-686
Author(s):  
Wen Jiang Zhang ◽  
Er Xia Du ◽  
Bei Zhan Liu ◽  
Shao Chong Yang
Keyword(s):  
Failure Mode ◽  
Material Properties ◽  
High Strength Concrete ◽  
Failure Modes ◽  
Steel Plate ◽  
High Strength ◽  
Shear Connector ◽  
Related Factors ◽  
Shear Connectors ◽  
Attribution Analysis

Investigation on PBL shear connectors failure modes and their related factors is conducted. On the basis of analysis on the detail mechanism of PBL shear connectors failure modes, the relations between the construction factors and failure modes are summarized. A reasonable way of failure mode is proposed for exerting the material properties of all components in PBL shear connector. As reference to construction and design of PBL shear connector, it is advised that the high strength concrete should be used, and the strength of steel plate should be not less than that of rebar. The position and posture of rebar cannot be ignored.

Seismic performance of prefabricated high-strength concrete tube column–steel beam joints

2017 ◽  
Vol 21 (5) ◽  
pp. 658-674 ◽  
Author(s):  
Xizhi Zhang ◽  
Jiawei Zhang ◽  
Xuejian Gong ◽  
Shaohua Zhang
Keyword(s):  
Seismic Performance ◽  
High Strength Concrete ◽  
Failure Modes ◽  
High Strength ◽  
Frame Structure ◽  
Steel Beam ◽  
Seismic Region ◽  
Strength Concrete ◽  
Shear Connectors ◽  
Cracking Pattern

This study proposes a new type of fabricated hybrid frame structure, which is a prefabricated high-strength concrete tube column–steel beam joint hybrid frame structure. A series of six full-scale cruciform prefabricated high-strength concrete tube column–H-shaped beam joint specimens was tested under cyclic loading to investigate the seismic performance of the new fabricated hybrid frame structure. We designed the connection in the manner that the capacity of beam was higher than that of the column. The cracking pattern, failure modes, energy dissipation capacity, and strain profiles of the specimens were obtained and discussed. The test results showed that some specimens collapsed due to ring plate tearing failure and weld fracture, while other specimens collapsed due to column flexural failure. Shear connectors (i.e. shear studs and shear reinforcement) could ensure the reliable transmission of shear force, and the compound stirrups can effectively improve bearing capacity and joint ductility. The stiffness degradation of specimens was smooth with a linearly decreasing trend because of the prestressed reinforcement. The new joints could be applied in a seismic region.

scholarly journals Finite Element Analysis on Shear Behavior of High-Strength Bolted Connectors under Inverse Push-Off Loading

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 479
Author(s):  
Wei Wang ◽  
Xie-dong Zhang ◽  
Fa-xing Ding ◽  
Xi-long Zhou
Keyword(s):  
Finite Element ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Three Dimensional ◽  
High Strength ◽  
Element Model ◽  
Composite Beams ◽  
Element Analysis ◽  
Shear Connectors ◽  
Parametric Analyses

High-strength bolted shear connectors (HSBSCs), which can be demounted easily and efficiently during deconstruction, are recommended to replace the conventional steel studs in steel–concrete composite beams (SCCBs) to meet the requirements of sustainable development. The existing investigations on the behavior of HSBSCs mainly focus on the positive moment area of composite beams, in which the concrete slab is in compress condition. In this paper, a three-dimensional finite element model (FEM) was developed to investigate the performance of HSBSCs subjected to inverse push-off loading. Material nonlinearities and the interactions among all components were included in the FEM. The accuracy and reliability of the proposed FEM were initially validated against the available push-off test results. Load-carrying capacity and load–slip response of the HSBSCs under inverse push-off loading were further studied by the verified FEM. A parametric study was carried out to determine the influence of the concrete strength, the diameter and tensile strength of bolt and the clearance between the concrete slab and the bolt as well as the bolt pretension on the shear performance of HSBSCs. Based on the extensive parametric analyses, design recommendations for estimating the shear load at the first slip and load-bearing resistance of HSBSCs were proposed and verified.

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