Experimental studies on bolted glubam connections

2021 ◽  
pp. 136943322110179
Author(s):  
R.Z. Yang ◽  
Y. Xiao

This paper reports tensile and compressive test results of bolted glubam (glued laminated bamboo) connections. The tensile tests were carried out with two types of specimens designed for tensile loadings in the longitudinal and transverse directions in relevance to the orientations of the bidirectional bamboo strips (fibers). In each direction, the specimens were further divided into nine groups according to different combination conditions of end and edge spacings. Compressive tests were executed for three groups of bolted glubam connections, with varying thickness of the main board and bolting conditions. The tensile experiments show that the failure of the specimens is strongly influenced by the loading directions. Recommended end distance and side distance are provided, whereas the load carrying capacity is analyzed. Based on the compressive testing results, failure modes and load displacement relationships are analyzed, in which the yield bearing capacity is shown to be close to that given by the equations in existing design specifications for timber structure.

2011 ◽  
Vol 94-96 ◽  
pp. 1456-1462
Author(s):  
Xiao Hua Yang ◽  
Chao Yang Zhou ◽  
Xue Jun He ◽  
Teng Chen

In order to study the mechanical behaviors of post-tensioned unbonded prestressed concrete hollowed floors, a 1/4 scale post-tensioned unbonded prestressed reinforced concrete hollow slab-column structure model is used to act uniform distributed load on the floor. The test results showed that the load carrying capacity is enough. The points of maximum displacement are at the centers of slabs. By means of the experimental studies and elastic finite element analysis methods, the results showed that post-tensioned unbonded prestressed concrete hollowed floor presents anisotropy with layout of circular-tubes in one way. In direction parallel to layout of hollowed tubes, the continuity of floor is destruction and bending stiffness of slab is weakened. For studying the deformations of slab, it can still be considered continuous cross-slab in two directions.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
YouWu Xu ◽  
Jian Yao ◽  
Feng Hu ◽  
Ying Zhou ◽  
Shuai Jiang

Elliptical concrete-filled steel tubular (CFST) column is a new form of CFST columns, consisting of an outer elliptical tube filled with concrete. Although the study on mechanical performance of the elliptical CFST members is receiving more and more attention, they have been limited to static behavior. Against this background, an experimental study on elliptical CFST columns was carried out under combined axial compression and cyclic lateral loading. The failure modes, hysteretic curves, skeleton curves, load carrying capacity, deformability, stiffness degradation, and energy dissipation ability was obtained and discussed. The test results indicated that the elliptical CFST columns possess excellent seismic performance and ductility. Valuable experimental data were provided for the formulation of the theoretical hysteresis model of the elliptical CFST columns.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhaoyan Cui ◽  
Liuhui Tu ◽  
Ming Xu ◽  
Zhongfan Chen ◽  
Qingfeng Xu

The dowel-type connection is widely applied in timber and bamboo structures. It is ambiguous regarding the calculation method of engineered bamboo connections completely referred to the timber design codes. The steel-to-laminated bamboo dowel connections with slotted-in steel plate tests were conducted to investigate the mechanical performance under tension based on the ASTM-D5652-15. The effects of the thickness, dowel diameter, and end distance on the yield load, ultimate load, initial stiffness, and ductility of the connections were studied. The difference in the yield load for different end distance is negligible. With the same thickness of the connections, the lower the thickness to dowel diameter, the larger the load-carrying capacity. The three typical yield modes and corresponding load-displacement curves of the connections are observed. By considering the rigid-plastic model, the theoretical equation for the connections is proposed and proven to fit well with the experimental results. It presents a better prediction for the load-carrying capacity of steel-to-laminated bamboo dowel connections with slotted-in steel plate.


2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Qingfang Lv ◽  
Weiyang Wang ◽  
Ye Liu

In order to accord well with the requirements of sustainable development and green construction, a cross-laminated bamboo composed of an odd number of orthogonally oriented layers of bamboo scrimber is proposed in this paper. Adjacent bamboo layers are face-bonded by structural adhesives under pressure. The uniform mechanical and physical properties can be obtained through the orthogonal layup. Flexural performances of three groups of one-way CLB slabs and two groups of one-way CLB slabs strengthened with CFRP grids were investigated via four-point monotonic loading configuration until failure. Experimental parameters of thickness of the layer, number of layers, and manufacturing processes of CFRP grids were taken into consideration. Experimental observations showed that the failure of the CLB slab was brittle, and different failure modes were found in the CLB slab with CFRP grids via different manufacturing processes. Test results showed that the load-carrying capacity increased with the thickness of the layer, number of layers, and application of CFRP grids pressed in the bamboo layer, but the CFRP grids pressed in the interface of adjacent bamboo layers weakened the load-carrying capacity. The strain analysis demonstrated that the compression region was utilized with more efficiency via CFRP grids pressed in the bamboo layer, and the plane cross section assumption is suitable for both CLB slab and CLB slab strengthened with CFRP grids. A theoretical calculation method of flexural load-carrying capacity was proposed for the CLB slab, the accuracy of which was proved.


2010 ◽  
Vol 133-134 ◽  
pp. 1233-1239
Author(s):  
Li Xue Jiang ◽  
Feng Zhou ◽  
Qiao Wen Zheng

Four steel beam-column connections were tested under cyclic loads to investigate effects of the concrete cover and the cast-in-situ slabs on the failure modes, stiffness, load-carrying capacity, ductility and energy-dissipation capacity. The test results show that the stiffness and bending strength of the non-rigid steel connections are significantly increased due to the presence of concrete cover and the cast-in-situ slabs can further enhance the connections. Moreover, the connection with slab is prone to debonding failure along beam-slab interface resulting in a remarkable decrease of the stiffness and strength. Practical methods are also presented for analyzing and assessing the steel frames with non-rigid connections considering effects of concrete cover.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3013
Author(s):  
Leszek Czechowski

The paper deals with an examination of the behaviour of glued Ti-Al column under compression at elevated temperature. The tests of compressed columns with initial load were performed at different temperatures to obtain their characteristics and the load-carrying capacity. The deformations of columns during tests were registered by employing non-contact Digital Image Correlation Aramis® System. The numerical computations based on finite element method by using two different discrete models were carried out to validate the empirical results. To solve the problems, true stress-logarithmic strain curves of one-directional tensile tests dependent on temperature both for considered metals and glue were implemented to software. Numerical estimations based on Green–Lagrange equations for large deflections and strains were conducted. The paper reveals the influence of temperature on the behaviour of compressed C-profile Ti-Al columns. It was verified how the load-carrying capacity of glued bi-metal column decreases with an increase in the temperature increment. The achieved maximum loads at temperature 200 °C dropped by 2.5 times related to maximum loads at ambient temperature.


2021 ◽  
Vol 28 (1) ◽  
pp. 71-83
Author(s):  
Mazin Abdulrahman ◽  
Shakir Salih ◽  
Rusul Abduljabbar

In this research, an experimental study is conducted to investigate the behavior and strength of high strength reinforced concrete corbels externally bonded with CFRP fabric sheets and Plates with different patterns taking into account the effect of adopted variables in enhancing the ultimate strength; the effect of shear span to effective depth (a/d), configuration, type and amount of bonding. Eleven high strength reinforced corbels were cast and tested under vertical loads. Test results showed there was an improvement in the behavior and load carrying capacity of all strengthened corbels. An increasing in the ultimate strength of strengthened corbel by inclined CFRP strips reached to (92.1%) while the increasing reached to (84.21%) for using one horizontal CFRP Plates compared to un-strengthened reference specimen. Also, it can be conducted that the increase of (a/d) ratio from (0.6 to 0.8) resulted in decreasing by 21.05% in ultimate load capacity of corbels and from (0.4 to 0.6) by 31.25% and 58.69% in cracking and ultimate loads respectively Using CFRP .


1987 ◽  
Vol 2 (3) ◽  
pp. 77-80 ◽  
Author(s):  
Marvin R. Pyles ◽  
Joan Stoupa

Abstract In order to quantify the stump anchor capacity of small second-growth Douglas-fir (Pseudotsuga menziesii [Mirb]. Franco) trees, load tests to failure were conducted on 18 stumps from trees 7 to 16.5 in dbh. The tests produced ultimate loads that varied as the square of the tree diameter. However, the ultimate load typically occurred at stump system deformations that were far in excess of that which would be considered failure of a stump anchor. A hyperbolic equation was used to describe the load-deformation behavior of each stump tested and was generalized to describe all the test results. West. J. Appl. For. 2(3):72-80, July 1987.


2017 ◽  
Vol 26 (6) ◽  
pp. 096369351702600
Author(s):  
Min Hou ◽  
Jiangfeng Dong ◽  
Lang Li ◽  
Shucheng Yuan ◽  
Qingyuan Wang

In order to make an effective use of the recycled aggregate concrete (RAC), a total of six steel tube RAC columns and six basalt fiber (BF) reinforced RAC columns, including six columns that were externally strengthened with aramid fiber reinforced polymer (AFRP) sheets, were fabricated and tested. This were to provide a strengthening solution to upgrade the load carrying capacity, ductility and rigidity of the RAC filled steel tube columns. Besides, the recycled coarse aggregate (RCA) replacement ratios for production of RAC was analyzed. The results show that the load carrying capacity and ultimate displacements of the RAC filled ST columns could be improved greatly by adding of basalt fiber, especially for the specimens with 50% and 100% RCA replacement ratio. The similar result was also found for the specimens strengthened with AFRP reinforcement, along with the stiffness of the columns were enhanced obviously. Moreover, the highest improving on the load carrying capacity, stiffness and ultimate displacement was found in the specimens both reinforced by adding of BF and strengthening of AFRP. However, the failure modes of the specimens with BF reinforced RAC gave a higher deformability than the one with AFRP strengthening arrangement.


2020 ◽  
Vol 54 (26) ◽  
pp. 4025-4034
Author(s):  
Chang Xu ◽  
Wenjing Wang ◽  
Zhiming Liu ◽  
Chen Fu

As the weakness zone of composite structures, joints are of great concern. Adding fasteners in the bonded joint is another type of jointing, technology used in engineering. In this research, considering a new type of flat-joggle-flat carbon fibre reinforced plastic (CFRP) joint, a prediction model based on the commercial software ABAQUS was proposed to predict the joint load carrying capacity and analyse the joint failure modes. Tensile tests were performed to verify the validity of the model. Furthermore, the orthogonal design was applied to explore the effects of four kinds of factors on the hybrid joints. The results showed that the load-carrying capacity of the hybrid joint improved by 40.5% and 31.9% on average, compared with that of the adhesively bonded joint and the bolted joint, respectively. The carrying capacity for the bonded joint, bolted joint and hybrid joint predicted by the model has error values of 3.5%, 2.7% and 3.1%, respectively, which illustrates good accuracy with the test results. The width-to-diameter ratio appears to have the most substantial effect on the first drop load and the maximum load of the hybrid joint. The failure modes are influenced by the width-to-diameter ratio, edge-to-diameter ratio and stacking sequence.


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