scholarly journals Experimental investigations into the mechanical performance of glulam dowel-type connections with either bolts or screws as fasteners

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Zheng Li ◽  
Wei Feng ◽  
Jiajia Ou ◽  
Feng Liang ◽  
Minjuan He
Keyword(s):  
Failure Modes ◽  
Mechanical Performance ◽  
Damping Ratio ◽  
Experimental Investigations ◽  
Bolted Connections ◽  
Equivalent Viscous Damping ◽  
Moment Resisting ◽  
Loading Tests ◽  
Cyclic Loading Tests ◽  
Ductility Ratio

AbstractDowel-type connections are the most common connections in glulam structures. Bolts are often used as fasteners for dowel-type connections. However, the clearance between the bolts and the pre-drilled bolt holes leads to low rotational stiffness and insufficient moment-resisting capacity. To achieve better mechanical performance, screws can be used as alternative fasteners for dowel-type connections. In this paper, monotonic and cyclic loading tests were conducted on glulam dowel-type connections with either bolts or screws as fasteners. The failure modes, moment-resisting capacity, ductility ratio, stiffness degradation, and equivalent viscous damping ratio of the specimens were analyzed and reported. Results showed that compared with traditional bolted connections, the screwed connections had larger moment-resisting capacity and better ductility. The hysteretic loops of the screwed connections were plumper, and the pinching effect was gentler compared to those of traditional bolted connections.

scholarly journals Experimental Study on the Seismic Performance of a Partition Damped Wall-Filled Frame Structure

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Shuainan Zhai ◽  
Zuyin Zou ◽  
Zhanyuan Zhu ◽  
Zixing Zhang ◽  
Wei Liang ◽  
...  
Keyword(s):  
Failure Modes ◽  
Lateral Displacement ◽  
Steel Frame ◽  
Frame Structure ◽  
Comparison Analysis ◽  
Significant Damage ◽  
Loading Tests ◽  
Energy Dissipation Capacity ◽  
Mechanical Performances ◽  
Cyclic Loading Tests

In the past, earthquakes have caused significant damage to traditional masonry filler wall frame structures. To solve this problem, a new design scheme, the partition damping filler wall, is proposed in this paper to reduce the interaction between the filler wall and the frame structure. Low cyclic loading tests are carried out on the traditional and the new masonry filler wall frames. Besides, one full-scale-angled span layer frame without a filler wall is produced for comparison analysis. The mechanical performances of the different frames are studied, including the characteristics of the deformation failure modes, hysteretic curves, skeleton curves, rigidity degeneration, energy dissipation capacity, and the lateral displacement of the frame columns. The research results show that the partition damping filler wall can significantly decrease the diagonal bracing effect of the filler wall on the steel frame. Meanwhile, the setting of the low-strength mortar between the filler wall and steel frame and the arrangement of the damping layer can improve the stress distribution and delay the crack development of the wall. Furthermore, the stiffness degradation rate of the partition damping filler wall is obviously slower than that of the traditional masonry filler wall frame structure. In this paper, the partition damped wall-filled frame structure shows outstanding ductility and deformation capacity.

Experimental Study on Seismic Performance of Steel Reinforced Concrete Column with Recycled Coarse Aggregate

2012 ◽  
Vol 256-259 ◽  
pp. 2063-2066
Author(s):  
Hui Ma ◽  
Jian Yang Xue ◽  
Xi Cheng Zhang ◽  
Zong Ping Chen
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Failure Modes ◽  
Coarse Aggregate ◽  
Reinforced Concrete Column ◽  
Steel Reinforced Concrete ◽  
Recycled Coarse Aggregate ◽  
Proper Design ◽  
Loading Tests ◽  
Cyclic Loading Tests

In order to evaluate whether concrete with recycled coarse aggregate can be applied for steel reinforced concrete (SRC) under the earthquake, low cyclic loading tests of SRC with different recycled coarse aggregate (RCA) replacement percentage were carried out in this paper. Based on the tests of three SRRC column specimens, the failure modes, the hysteresis curves, the skeleton curves, the ductility, and the stiffness degradation of SRRC columns are investigated. The influence of variation in the RCA replacement percentage on the SRRC column is analyzed in detail. Test results show that the seismic performance of SRRC column is reduced to an allowable extent with the increasing magnitude of the RCA replacement percentage. The SRRC column still has a good seismic performance and the recycled coarse aggregate can be applied for steel reinforced concrete through the proper design.

Seismic Performance of Medium Thick-Walled Cold-Formed Steel Top-and-Seat Angle Joint

2014 ◽  
Vol 501-504 ◽  
pp. 1609-1614
Author(s):  
Zhong Peng ◽  
Jun Huang ◽  
Shao Bin Dai ◽  
Ji Xiong Liu
Keyword(s):  
Energy Dissipation ◽  
Failure Modes ◽  
Mechanical Performance ◽  
High Strength ◽  
Initial Stiffness ◽  
Element Analysis ◽  
Equivalent Viscous Damping ◽  
Seat Angle ◽  
Cold Formed Steel ◽  
Energy Dissipation Capacity

3 medium thick-walled cold-formed steel top-and-seat angle joints were designed. The ABAQUS nonlinear finite element analysis on earthquake resistance behaviors of the joints were conducted under low cyclic loading. The results indicate that the failure processes and failure modes of 3 specimens are basically the same, the destruction of joints derive from buckling deformation of the top-and-seat angle and buckling of the steel beam flanges; the shapes of hysteresis curves of all specimens are obvious pinch together and present spindle, the displacement ductility factors are greater than 5.5, the equivalent viscous damping factors are greater than 0.158, all the specimens possess good energy dissipation capacity. The secant stiffness variations are almost similar, each specimen represents significant degradation. Increase the thickness of angle and diameter of high-strength bolt can improve the mechanical performance of the joints. Increase the bolt diameter, the ductility, energy dissipation capacity and initial stiffness enhance obviously, however, there is no apparent effect while increasing the thickness of angle.

Lateral Resisting Experiment of Prestressed-Tube Bolted Connection for Post-and-Beam Timber Construction

2013 ◽  
Vol 778 ◽  
pp. 631-638 ◽  
Author(s):  
Min Juan He ◽  
Yi Zhao ◽  
Ren Le Ma
Keyword(s):  
Damping Ratio ◽  
Hysteresis Curve ◽  
Lateral Stiffness ◽  
Loading Test ◽  
Bolted Connection ◽  
Equivalent Viscous Damping ◽  
Timber Construction ◽  
Moment Resisting ◽  
Good Potential ◽  
Timber Connections

Connections are key elements and the weak points for timber structures. The most commonly used bolted timber connections with slotted in steel plate have low lateral stiffness and poor ductility in post-and-beam construction. This paper introduces the prestressed-tube bolted connection to alleviate this problem. To evaluate its lateral resisting performance, the failure mode, strength, lateral stiffness, ductility, hysteresis curve and equivalent viscous damping ratio of the ordinary and improved connections, as determined by the monotonic and reversed cyclic loading test, are compared. The results demonstrate that the lateral stiffness of the prestressed-tube bolted connection has been significantly improved, and its ductility is also better than the normal bolted connection with no decrease in the ultimate moment resisting capacity. It is believed that the semi-rigid prestressed-tube bolted connection, as an alternative to current bolted solutions, may provide reasonable lateral stiffness and has good potential for use in post-beam timber construction.

scholarly journals Cyclic Behavior and Modeling of Bolted Glulam Joint with Cracks Loaded Parallel to Grain

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Jing Zhang ◽  
Zhi-Fang Liu ◽  
Yong Xu ◽  
Mai-Li Zhang ◽  
Liu-Cheng Mo
Keyword(s):  
Failure Modes ◽  
Damping Ratio ◽  
Three Dimensional ◽  
Material Model ◽  
Elastic Stiffness ◽  
Hysteretic Behavior ◽  
Cyclic Behavior ◽  
Equivalent Viscous Damping ◽  
Energy Dissipated ◽  
Initial Cracks

Under varying humidity and temperature conditions, with the constraint of metal fasteners to wood shrinkage, cracks along the bolt lines are generally observed in bolted glulam joints. A three-dimensional (3D) numerical model was established in software package ANSYS to investigate the cyclic behavior of bolted glulam joints with local cracks. A reversed cyclic loading was applied in the parallel-to-grain direction. The accuracy of numerical simulation was proved by comparison with full-scale experimental results. Typical failure modes were reproduced in the numerical analysis with the application of wood foundation zone material model and cohesive zone material model. The effect of crack number and length on the hysteretic behavior of bolted glulam joints was quantified by a parametric study. It was found that initial cracks impair the peak capacity and elastic stiffness of bolted glulam joints significantly. More decrease in capacity was observed in joints with more cracks, and longer cracks affect elastic stiffness more dramatically. Moreover, with the existence of initial cracks, the energy dissipated and equivalent viscous damping ratio of bolted joints are reduced by 24% and 13.3%, respectively.

scholarly journals Experimental Analyses of Mechanical Performance of CFST Column to Assembled Steel H-Beam Connections

2014 ◽  
Vol 8 (1) ◽  
pp. 270-278 ◽  
Author(s):  
Cui Chunyi ◽  
Zhao Jinfeng ◽  
Zhang Yannian ◽  
Zuo Wenxin
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Compression Ratio ◽  
Mechanical Performance ◽  
Axial Compression Ratio ◽  
Ring Plate ◽  
Loading Tests ◽  
Hysteretic Characteristics ◽  
H Beam ◽  
Cyclic Loading Tests

The mechanical performance of a new proposed type of cross-shaped connection with concrete-filled steel tubular (CFST) column and assembled steel H-beam was investigated. Cyclic loading tests on the cross-shaped connections are carried out by using MTS servo loading system. Comparative analyses are conducted based on the experimental results including hysteretic curves, skeleton curves and stiffness degradation curves as well as ductility coefficients of cyclic loading tests. Furthermore, effects of geometric parameters of ring-stiffened plate, axial compression ratio and backing plate on the deformation performance of cross-shaped connections are analyzed. The results show that the increase of width of ring plate and the shape change of ring plate from square to circle can both significantly improve the ductility and the hysteretic characteristics of connection. It is emphasized that the specimen with square ring plates is of better deformation performance but lower bearing capacity than the ones with circular ring plates. Besides, the backing plates always have positive effects on the hysteretic characteristics, ductility and energy dissipation of the CFST column connections. Conversely, the increase of axial compression ratio contributes negatively to both the bearing capacity and deformation performance of the connection specimens. It can be concluded that the presented cross-shaped connection is of good deformation performance relating to hysteretic characteristics, energy dissipation and ductility, which can provide reference towards engineering practice with potential perspective application.

scholarly journals Axial Compression Behaviours of Pultruded GFRP–Wood Composite Columns

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 755 ◽  
Author(s):  
Yujun Qi ◽  
Lei Xie ◽  
Yu Bai ◽  
Weiqing Liu ◽  
Hai Fang
Keyword(s):  
Axial Compression ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Slenderness Ratio ◽  
Experimental Investigations ◽  
Wood Composite ◽  
Compression Tests ◽  
Element Analysis ◽  
Load Bearing ◽  
Global Buckling

An innovative pultruded fiber reinforced polymer (FRP)–wood composite (PFWC) column with a lightweight southern pine wood core confined by outer FRP sheets was manufactured using an improved pultrusion process. Axial compression tests with both ends pinned as boundary conditions were employed to investigate the mechanical performance of such PFWC columns under concentric load. Through experimental investigations, the effects of the slenderness ratio on the failure modes and the axial load bearing capacities of the PFWC columns were evaluated. The failure modes showed that the specimens with a slenderness ratio less than 43.2 failed through compressive failure at junctions on FRP sheets, while those with slenderness ratios larger than 57.6 showed global buckling. Strain responses on specimens with different slenderness ratios are consistent with the observed failure modes. Finite element analysis was carried out to validate the experimental results, and satisfactory agreement was found between the failure modes and load–displacement curves. An empirical equation was developed with a new factor taking 0.65 into account to predict the load bearing capacities of the PFWC columns, and good agreement was found.

scholarly journals Seismic Performance Evaluation of RC Columns Retrofitted by 3D Textile Reinforced Mortars

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 592
Author(s):  
Siyun Kim ◽  
Sung Jig Kim ◽  
Chunho Chang
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Lateral Force ◽  
Hysteretic Behavior ◽  
Rc Columns ◽  
Seismic Performance Evaluation ◽  
Loading Tests ◽  
3D Textiles ◽  
Cyclic Loading Tests ◽  
Ductility Ratio

The paper investigates the seismic performance of rectangular RC columns retrofitted by a newly developed 3D Textile Reinforced Mortar (TRM) panel. The 3D-TRM used in this study consists of two components: self-leveling mortar and 3D textiles. Firstly, the flexural capacity of the 3D-TRM panel was investigated through the four-point flexural test. Secondly, a total of five specimens were constructed and experimentally investigated through static cyclic loading tests with constant axial load. One specimen was a non-seismically designed column without any retrofit, while the others were strengthened with either the 3D-TRM panel or conventional Fiber Reinforced Polymer (FRP) sheets. Experimental results in terms of hysteretic behavior, ductility ratio, and energy dissipation are investigated and compared with the cases of specimens with conventional retrofitting methods and without any retrofit. The maximum lateral force, ductility, stiffness degradation, and energy dissipation of RC columns with 3D-TRM panels were significantly improved compared with the conventional RC column. Therefore, it is concluded that the proposed retrofitting method can improve the seismic performance of non-conforming RC columns.

scholarly journals Experimental Study on In-Plane Seismic Performance of Reinforced Brick Walls Bonded with Mud

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Hui Wang ◽  
Jian-jun Chang ◽  
Shi-qin He ◽  
Qing-lei Zhang
Keyword(s):  
Experimental Study ◽  
Cyclic Loading ◽  
Bearing Capacity ◽  
Seismic Performance ◽  
Failure Modes ◽  
Cement Mortar ◽  
Experimental Results ◽  
Loading Tests ◽  
Low Cyclic Loading ◽  
Cyclic Loading Tests

Low-cyclic loading tests were carried on brick walls bonded with mud reinforced by three methods: packing belts, one-side steel-meshed cement mortar, and double-side steel-meshed cement mortar. The failure modes, hysteresis curves of the load-displacement, skeleton curves, and ductility were obtained. The results showed that the bearing capacity of the brick walls bonded with mud reinforced by the abovementioned three methods had been increased to 1.4, 1.7, and 2.2 times as much as that of the unreinforced brick walls, respectively, and the ductility of the reinforced brick walls had been increased to 4.7, 2.1 and 2.2 times, respectively. The integrity and ductility of the reinforced brick walls were effectively improved in different degrees. The experimental results provided specific seismic strengthening techniques for the farmhouses built with brick walls bonded with mud.

scholarly journals Experimental and Numerical Investigation of Light-Wood-Framed Shear Walls Strengthened with Parallel Strand Bamboo Panels

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1447
Author(s):  
Jing Di ◽  
Hongliang Zuo
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Shear Walls ◽  
Elastic Stiffness ◽  
Monotonic Loading ◽  
Construction Costs ◽  
Element Analysis ◽  
New Type ◽  
Loading Tests ◽  
Ductility Ratio

This paper describes experimental and numerical investigations on a new type of strengthened light-wood-framed (LWF) shear wall (SW) that has parallel strand bamboo (PSB) panels at each end. The experiments are divided into two parts: (1) monotonic loading tests of panel-to-frame joints representing different positions along the wall; (2) monotonic loading tests of a group of traditional full-scale SWs and two groups of strengthened walls with nailed or screwed PSB panels. The failure modes, load–displacement curves, ultimate bearing capacity, elastic stiffness, and dissipation are analyzed, and the mechanical properties of panel-to-frame joints and the lateral performance of SWs are discussed. Moreover, nonlinear finite-element analysis shows that the numerical results are in good agreement with the test results. Our findings suggest that using LWF SWs strengthened with nailed PSB panels effectively improves the failure mode and the ductility, stiffness, and dissipation of traditional walls. Using sheathing screws on the PSB panels increases the lateral bearing capacity and the dissipation of the walls, but decreases their ductility ratio. Setting end PSB panels improves the overturning resistance capacity by restricting the uplift of studs. The LWF SWs strengthened with end PSB panels are found to meet the design requirements and reduce construction costs.

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