Abstract

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.

Highlights

  • Box girder cracking and mid-span deflection are common problems of prestressed concrete (PSC)continuous box girder bridges (CBGBs) around the world [1,2,3,4,5]

  • Due to the ultimate strength of the MC-35 FE model is higher than the test value, the yield strengths of the MC-35 pressure plates were set to 550 MPa, and others were set to the test values; the yield strength of the high-strength bolted (HSB) was set to 940 MPa; the material density was set to 7850 kg/m3 ; the Young’ modulus was set to

  • This paper designed a novel friction-type high-strength bolted (FHSB) T-stud connection based on the structural features in the anchorage zone of a cable-stayed system (CSS)-enhanced PSC-CBGB

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Summary

Introduction

Box girder cracking and mid-span deflection are common problems of prestressed concrete (PSC). The results show a positive correlation between cable force, the pressure on the contract surfaces and the loss of shear force and the clamping force of the bolt This calls for further analysis on the friction load of FHSB connections [23]. The shear–compression ratio was adjusted by changing the size of the pressure plate On this carried out on 21 specimens under different shear–compression ratios, and the FE models were basis, the authors compared the specimens in failure mode, initial friction load and ultimate strength, created for each specimen. The shear–compression ratio was adjusted by changing the size of the summed up the relationship between shear capacity verified the FE pressure plate On this basis, the authors comparedand theshear–compression specimens in failure ratio, mode,and initial friction models.

Selection
Specimens
D D r d dD ttdes
Failure Modes of FHSB T-Stub Connection
Relationship between Compression Load and Strains of Bolt
Relationship between Shear–Compression Ratio and Pressure Features
Initial Friction Load of FHSB T-Stub Connection
Ultimate Strength of FHSB T-Stub Connection
Finite-Element Modeling
Validation of Test Results
Parametric Analysis Results
Effect of Friction Coefficient
Effect of the Shear–Compression Ratio
Effect of the Bolt Diameter
Effect of the Clamping Force
Bearing Capacity of the FHSB T-Stub Connection
Conclusions
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