scholarly journals Study on an Innovative Flange Bolted-Welded Connection

2015 ◽  
Vol 9 (1) ◽  
pp. 870-875
Author(s):  
Yufeng Jiao ◽  
Guo Zhao

This paper proposes a new type of spliced joint, named flange bolted-welded hybrid joint, which is designed to splice I-shape beam to facilitate the construction of industrialized buildings. The flange, welded with the bottom beam flange as well as the web close to bottom flange, are jointed by high strength bolts. Stiffening plate is welded at top of the flange while downhand welding and high strength friction grip bolts are used for the top beam flange and the beam web, respectively. The connection reduces the construction period and costs. In this paper, monotonic and reversed cyclic loading tests were conducted on three full-scale specimens of this innovative joint to investigate its load-bearing capacity, energy-dissipating capacity and failure modes. The results indicate that the joint has high load-bearing capacity and great ductility. The failure mode is due to the slippage of flange bolts as well as the gap development between the two flange plates. The experimental studies enabled improvement of the design of the connection to be used in moment-resisting steel frame structures.

2016 ◽  
Vol 20 (10) ◽  
pp. 1572-1585 ◽  
Author(s):  
Zi-qin Jiang ◽  
Yan-lin Guo ◽  
Ai-Lin Zhang ◽  
Chao Dou ◽  
Cai-Xia Zhang

The double rectangular tube assembled buckling-restrained brace is a new type of buckling energy consumption buckling-restrained brace. Because of its external restraining members, which are bound by high-strength bolts, its mechanical mechanism is more complicated and its failure modes are more varied. In this study, the double rectangular tube assembled buckling-restrained brace composition and three types of end constructions are introduced in detail. The influences of different design parameters on the performance of double rectangular tube assembled buckling-restrained brace are studied by numerical analysis methods; the possible failure modes and the influence of the end strengthening construction of double rectangular tube assembled buckling-restrained brace are also investigated, and a number of suggestions are proposed to improve this design. This study shows that the pinned double rectangular tube assembled buckling-restrained brace has four types of typical failure modes, namely, overall buckling failure, external end local pressure-bearing failure, bending failure of the extended strengthened core region and bolt threading failure. Rational design can prevent a buckling-restrained brace from losing its load-bearing capacity. In addition, compared with the end strengthening scheme with an external hoop, the end strengthening scheme with a strengthened bench can improve the load-bearing capacity of the double rectangular tube assembled buckling-restrained brace more effectively, and a reasonable design can also save materials.


2017 ◽  
Vol 2017 ◽  
pp. 1-20
Author(s):  
Ulf Arne Girhammar ◽  
Bo Källsner

The authors present an experimental and analytical study of slotted-in connections for joining walls in the Masonite flexible building (MFB) system. These connections are used for splicing wall elements and for tying down uplifting forces and resisting horizontal shear forces in stabilizing walls. The connection plates are inserted in a perimeter slot in the PlyBoard™ panel (a composite laminated wood panel) and fixed mechanically with screw fasteners. The load-bearing capacity of the slotted-in connection is determined experimentally and derived analytically for different failure modes. The test results show ductile postpeak load-slip characteristics, indicating that a plastic design method can be applied to calculate the horizontal load-bearing capacity of this type of shear walls.


2010 ◽  
Vol 163-167 ◽  
pp. 2171-2175 ◽  
Author(s):  
Jun Ping Liu ◽  
Yong Jian Liu ◽  
Jian Yang

Based on the experimental results, this paper presents the effects of concrete-filled in chord on the static behavior of rectangular hollow section (RHS) steel tubular trusses, including failure modes, load bearing capacity and structural stiffness. Failure of RHS trusses occurs at joints wether concrete-filled in chord or not, concrete-filled in chord changed the failure mode. Load bearing capacity and stiffness of joints subjected to compression load increased significantly, while it is limited to the tension joints. Concrete-filled in the compression chord tube can increase its stiffness significantly, while tension chord tube, it is not that obvious. Finally, based on the results discussed, failure modes and their formulas of calculating the load bearing capacity are discussed. Meanwhile, two methods, that is, amplified factor method and stiffness discounting method, which calculate the structural displacement when considering the joint deformation effects are presented.


2011 ◽  
Vol 311-313 ◽  
pp. 1941-1944
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo ◽  
Xiao Yan Sun

intermediate crack-induced debondingis one of the most dominant failure modes in FRP-strengthened RC beams. Different code models and provisions have been proposed to mitigateintermediate crack-induced debondingfailure.However, these models and provisions can not mitigate this failure mode effectively. Recnetly, new models have been proposed to solve this problem. Out of all the existing models, four typical ones are investigated in the current study. A comprehensivecomparison among these models is carried out in order to evaluate their performance and accuracy. Test results offlexural specimens with intermediate crack-induced debonding failurecollected from the existing literature are used in the current comparison. The effectivenessand accuracy of each model have been evaluated based on these experimental results. It is shown that the current modals are all conservative and inadequite to effectively mitigate intermediate crack-induced debonding in flexurally strengthened members.


2016 ◽  
Vol 711 ◽  
pp. 564-571 ◽  
Author(s):  
Thomas Gernay

The use of high strength concrete (HSC) in multi-story buildings has become increasingly popular. Selection of HSC over normal strength concrete (NSC) allows for reducing the dimensions of the columns sections. However, this reduction has consequences on the structural performance in case of fire, as smaller cross sections lead to faster temperature increase in the section core. Besides, HSC experiences higher rates of strength loss with temperature and a higher susceptibility to spalling than NSC. The fire performance of a column can thus be affected by selecting HSC over NSC. This research performs a comparison of the fire performance of HSC and NSC columns, based on numerical simulations by finite element method. The thermal and structural analyses of the columns are conducted with the software SAFIR®. The variation of concrete strength with temperature for the different concrete classes is adopted from Eurocode. Different configurations are compared, including columns with the same load bearing capacity and columns with the same cross section. The relative loss of load bearing capacity during the fire is found to be more pronounced for HSC columns than for NSC columns. The impact on fire resistance rating is discussed. These results suggest that consideration of fire loading limits the opportunities for use of HSC, especially when the objective is to reduce the dimensions of the columns sections.


2020 ◽  
Vol 8 (3) ◽  
pp. 36-39
Author(s):  
Yulia Kustikova

The results of experimental studies and tests of concrete structures with basalt-plastic reinforcement to determine the load-bearing capacity, as well as the mechanism of adhesion of basalt-plastic rods to concrete are considered.


Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 647 ◽  
Author(s):  
Tsai-Po Chien ◽  
Te-Hsin Yang ◽  
Feng-Cheng Chang

In this study, Japanese cedar (Cryptomeria japonica (L. f.) D. Don) harvested from a plantation in Taiwan was used to develop built-up beams using self-tapping screws as metal connectors and resorcinol formaldehyde resin as glue to assemble components based on various assembly configurations. Results showed that adding glue provided flexural rigidity, whereas assembly using self-tapping screws resulted in built-up beams with high ductility but relatively low flexural bearing capacity. Beams used glue exhibited approximately linear behavior, whereas those using only screws exhibited some undulating and stepwise responses, implying that shear force between the flanges and the web may cause buckling as well as the dislocation of the self-tapping screws. When using components of similar grades, adding another web can improve the performance. Furthermore, the grades of flanges can strongly influence the flexural load-bearing capacity. In addition, a smaller spacing between the screws can improve the flexural load-bearing performance, but also cause wooden components to crack. Typical bending failure modes were observed in the developed built-up beams, indicating tension failure of the bottom flange as well as slippage between flanges and the web due to horizontal shear, which also caused buckling deformations in the screws.


Author(s):  
Anne K. Kawohl ◽  
Jörg Lange

Prior investigations of the load bearing capacity of bolts during fire have shown differing behaviour between bolts that were loaded by shear or by tensile loads. The interaction of the two loads has not yet been examined under fire conditions. This paper describes a preliminary test series on the post-fire performance of high-strength bolts of the property class 10.9 under combined tension and shear. The results show that how the bolt is loaded influences the load bearing capacity. It is assumed that this is also true at elevated temperatures. Further, atest set-up for experiments at elevated temperatures and a more detailed test series on the post-fire performance under combined tension and shear is presented.


Author(s):  
Marat Z. Yamilev ◽  
◽  
Egor А. Tigulev ◽  
Andrey А. Raspopov ◽  
◽  
...  

The metal welding is accompanied by the formation of mechanically non-homogenous sections of welded connection. The pipeline welded connections also have sections, which are different in structure, chemical composition and mechanical properties. The mechanical inhomogeneity affects the load bearing capacity of welded connection and the structure as a whole, which is necessary to take into consideration when performing calculation analysis. So far, the specialists have established the dependencies in assessment of welded connection strength with various types of heterogeneous sections. However, this phenomenon has received little attention in case of pipeline welded connections made of low carbon steels. The existing theoretical models do not reflect actual anisotropy of mechanical properties of the welded connections and weld adjacent zone. The present study considers the model of welded connections of K56 pipe steels with various strength characteristics of sections of welded seam and weld adjacent zone, without defects. The assessment of mechanical inhomogeneity influence on load bearing capacity of welded connections was performed by applying the finite-element modelling of its stress-strain state. The developed numerical model helps to determine and optimize the criteria of testing of full scale samples of pipe steel welded connections with regards to the implementation of local strengthening effect. The research results demonstrated that the degree of contact strengthening in welded connections with X-shape grooving is higher than in welded connections with V-shaped grooving by 8 % at similar relative thickness of soft interlayer. The suggested numerical model can be applied for detailed calculations of pipelines with regards to the mechanical inhomogeneity of its welded connections.


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