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With the development of blind bolts that can be installed from the outer side of a section, the application of steel pipe hollow sections in prefabricated structures has become possible. The novel one-side bolt with a flip-top collapsible washer (FTW-OSB) is proposed, which can fold the washer at the end of the bolt to achieve a simple and efficient installation. Firstly, the components and installation process of the FTW-OSB are introduced. Additionally, axial tensile tests were carried out on three types of new bolts, and the failure mode, load–displacement curve, and ultimate capacity were analyzed. Based on this, the finite element model was verified, and through a series of finite element parameter analyses, the influence of washer size and construction, the friction coefficient, and the contact surface size on the new bolt were analyzed and optimized. The results show that the L-shaped washer can prevent washer rotation and has better anchoring performance than the I-shaped washer. The washer thickness, height, and upper contact surface size are the key factors affecting the anchoring performance of the FTW-OSB bolt. Among these factors, when the washer thickness increases from 0.1 d0 to 0.3 d0, the ultimate capacity and initial stiffness of the FTW-OSB bolt increase by 136.5% and 100.3%, respectively. The lower contact surface size and friction coefficient can be ignored. The failure model of the FTW-OSB is mainly washer shear failure and bolt tension failure. By effectively adjusting the washer thickness, side wall height, and upper contact surface size, shear failure of the washer can be avoided and an anchoring performance can be achieved that is the same as that of the same type of 10.9-grade ordinary high-strength bolt. [ABSTRACT FROM AUTHOR]

With the development of blind bolts that can be installed from the outer side of a section, the application of steel pipe hollow sections in prefabricated structures has become possible. The novel one-side bolt with a flip-top collapsible washer (FTW-OSB) is proposed, which can fold the washer at the end of the bolt to achieve a simple and efficient installation. Firstly, the components and installation process of the FTW-OSB are introduced. Additionally, axial tensile tests were carried out on three types of new bolts, and the failure mode, load–displacement curve, and ultimate capacity were analyzed. Based on this, the finite element model was verified, and through a series of finite element parameter analyses, the influence of washer size and construction, the friction coefficient, and the contact surface size on the new bolt were analyzed and optimized. The results show that the L-shaped washer can prevent washer rotation and has better anchoring performance than the I-shaped washer. The washer thickness, height, and upper contact surface size are the key factors affecting the anchoring performance of the FTW-OSB bolt. Among these factors, when the washer thickness increases from 0.1 d0 to 0.3 d0, the ultimate capacity and initial stiffness of the FTW-OSB bolt increase by 136.5% and 100.3%, respectively. The lower contact surface size and friction coefficient can be ignored. The failure model of the FTW-OSB is mainly washer shear failure and bolt tension failure. By effectively adjusting the washer thickness, side wall height, and upper contact surface size, shear failure of the washer can be avoided and an anchoring performance can be achieved that is the same as that of the same type of 10.9-grade ordinary high-strength bolt.

Copyright of Journal of Southeast University / Dongnan Daxue Xuebao is the property of Journal of Southeast University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The failure mechanism of thread-fixed one-side bolted T-stubs under tension was investigated by a finite element model to provide basic knowledge for its potential application in bolted beam-column endplate connection. The finite element model was verified through experimental results by considering four possible reference issues: the T-stub deformation, the force–displacement curve, the failure mode and the yield strength. Studied parameters included the bolt diameter ( d ), the bolt spacing ( s ) and the T-stub plate strength ( f y ). Based on numbers of plastic hinges in the T-stub flange, the failure modes were divided into three categories: Mode 1, complete flange yielding; Mode 2, flange yielding accompanied by bolt failure or hole thread failure; and Mode 3, bolt failure or hole thread failure. Furthermore, modified design equations integrating the potential hole thread failure were proposed to analyze the failure mode and the yield strength of the T-stub connection. Theoretical and numerical analyses showed that the thread hole could provide enough clamping force to fix the high strength bolt, which assured that the one-side bolted T-stub connection would not fail caused by pre-mature thread failure. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Failure modes and their corresponding tension strengths of thread-fixed one-side bolted T-stub were investigated experimentally and theoretically. The thread resistances of bolts fixed directly to plates were evaluated by experimental analysis. Except for the three failure modes described in the current Eurocode 3, two new failure modes and their corresponding design methods were proposed, which were (a) hole thread failure and (b) T-stub flange yielding with hole thread failure. Influences of the bolt pre-tension force, the thickness of T-stub flange, the existence of the standard nut, the screw depth of the bolt on the failure mode and the ultimate tension strength were studied. The bolt pre-tension force had little influence on the ultimate tension strength; however, it could improve the initial stiffness of the connection. The ultimate tension strength and tension stiffness of the T-stub increased with the increase in flange thickness. For the T-stub with thin flange, the thread hole could also provide sufficient clamping force to ensure the bolted T-stub not fail by thread failure. The existence of the nut did not improve the yield strength of the T-stub; however, it could prevent the separation of two T-stubs after flange yielding, thus the ultimate tension strength was increased. It depended on the screw depth whether the partially screwed bolt was failed by thread failure or bolt failure. Ultimate tension strengths of the T-stub measured from tests were much higher than those calculated by design equations. And under the design load, the bolted T-stub was still in elastic state, which demonstrated the applicable of the thread-fixed one-side bolted T-stub. [ABSTRACT FROM AUTHOR]

Tests were carried out to investigate the one-side bolted T-stub through thread holes under tension strengthen with backing plate. For the thread length is limited by the flange thickness of T-stub, which might lead to the premature failure of the connection due to the failure of thread. The thread length could be increased by adding a backing plate. Two new failure models of the bolted T-stub were proposed to consider the potential failure of hole thread. And the design methods for tension strength of corresponding failure modes were presented. Studied parameters included the bolt pre-tension force and the T-stub flange thickness. The bolt pre-tension force almost did not affect the tension strength of a bolted T-stub, while the initial stiffness could be improved. Effects of the backing plate on the tension strength and load-displacement curve of T-stub under tension were presented through comparing those without backing plate. Test results showed that the backing plates could be efficiently improve the tension strength of the T-stubs. However, for T-stubs with same screw depth, it was more efficient to increase the flange thickness directly. The comparison between test results and calculated results from design methods indicated that the proposed design methods could be used to predict the tension strength and failure modes of the one-side bolted T-stub through thread holes and strengthened with screwed backing plates. Under the design load, the bolted T-stub was still in elastic state, which could meet the design requirement. [ABSTRACT FROM AUTHOR]

The One-side bolts are widely used in the connection of the closed section members in the prefabricated buildings. As a novel type of one-side bolt, T-head Square-neck One-side Bolt has the advantages of the simple structure, the convenient installation, and no need for special installation tools. In this paper, the sub-model for the tension region of the T-stub bolted beam-column connection was selected as the research object, and the cyclic test was conducted on four T-head Square-neck One-side Bolted Connections (TSOBCs) for T-stub to Hollow Section Steel Column (HSSC) and two Traditional High-strength Bolted Connections (THBCs) for comparison. The results of the test including the failure modes, the applied force-displacement hysteretic curves, the applied force-displacement envelope curves, the deformation capacity and ductility, the strength degradation, the stiffness degradation, the energy dissipation, and the strain evolution are discussed and analyzed in this paper. The experimental results denote that: (1) There are two failure modes in the test, mode i, HSSC wall yielding and mode ii, T-stub flange yielding; (2) The initial stiffness and peak bearing capacity of the TSOBCs decreased by 2.5% ~ 35.6% and 21.7% ~ 39.4%, respectively, compared with those of the THBCs; (3) When the failure mode ii occurred, the ductility and the equivalent damping coefficient of the TSOBC with vertical mounting holes are 42.5% and 5.4% higher than those of the THBC, respectively. Besides, the plastic deformation, rigid displacement, and bolt offset in the TSOBCs are analyzed using finite element models. [Display omitted] • A novel T-head Square-neck One-side Bolted Connection (TSOBC) was proposed. • Test on TSOBC of T-stub to hollow section column under cyclic load was conducted. • Cyclic performances of TSOBC were compared with traditional bolted connection. • Vertical mounting hole improves the ductility and energy dissipation of TSOBC. [ABSTRACT FROM AUTHOR]