Experimental Investigations on the Seismic Behavior of Precast Concrete Columns with Novel Box Connections

2019 ◽  
Vol 14 (02) ◽  
pp. 2050007
Author(s):  
Xizhi Zhang ◽  
Shengbo Xu ◽  
Shaohua Zhang ◽  
Gaodong Xu

In this study, two types of novel box connections were developed to connect precast concrete (PC) columns and to ensure load transfer integrity. Cyclic loading tests were conducted to investigate the seismic behavior of the PC columns with proposed connections as well as the feasibility and reliability of novel box connections. The failure mode, hysteretic behavior, bearing capacity, ductility, stiffness degradation and energy dissipation were obtained and discussed. The test results indicated that the all PC columns exhibited the ductile flexural failure mode and that the proposed connections could transfer the force effectively. The adoption of novel box connections could improve the deformation capacity and energy dissipation capacity of PC columns. A higher axial compression ratio could enhance the bearing capacity of PC column with proposed connection but would significantly deteriorate the ductility and energy dissipation capacity. Finite element models were developed and the feasibility of the models was verified by the comparison with the test results.

2018 ◽  
Vol 22 (5) ◽  
pp. 1035-1048
Author(s):  
Qiuwei Wang ◽  
Qingxuan Shi ◽  
Yi Tao

A new type of fired perforated brick with void ratio of more than 30% has been developed to improve the applicability of brick masonry structures. When the new perforated bricks are used for load-bearing walls, it will be a question whether the seismic performance of walls could satisfy the requirements under not obviously increasing the cost. This article presents an experimental study to investigate the seismic behavior and shear capacity of new-type perforated brick walls with high void ratio. For this purpose, six cross walls and three longitudinal walls with constructional columns under low reversed cyclic loading were tested, and the failure patterns, hysteretic characteristics, skeleton curves, energy dissipation capacity, ductility and reinforcement strain were observed. The test results indicate that (1) most new-type perforated brick wall specimens display shear failure, and hysteretic curves of cross walls are plump while there is some pinch phenomenon for longitudinal walls; (2) the specimens have considerable deformation and energy dissipation capacity, with displacement ductility factors of over 2.0; (3) the bearing capacity of walls increases but the ductility decreases with an increase of vertical compressive stress, and the bearing capacity and deformation all increase while considering the effect of horizontal reinforcement; and (4) the central brick wall and construction columns could resist shear force together before the peak load, while the shear force would be mainly born by construction columns at the later loading stage. Based on the test results, the constraint coefficient in current Chinese code was modified, and the calculation formula of shear capacity for cross walls was proposed. Comparison of calculated results with test data shows that the method will provide a way to predict the shear capacity of new-type fired perforated brick walls.


2014 ◽  
Vol 919-921 ◽  
pp. 1812-1816 ◽  
Author(s):  
Quan Dong Xiao ◽  
Zheng Xing Guo

To study the seismic behavior of Double-Wall Precast Concrete (DWPC) shear wall, three full scale specimens are tested and compared under low-cyclic reversed loading, including two DWPC shear walls and one normal Cast-In-Situ (CIS) shear wall. By observing their experimental phenomena and failure modes, contrasting their displacement ductility coefficients, hysteretic curves, skeleton curves and energy dissipation capacity, the seismic behavior were synthetically evaluated on aspects of strength, stiffness, ductility and energy dissipation. Compared with CIS specimen, DWPC specimens have higher initial stiffness, increased cracking loads by 43% to 47%, and the ultimate loads increased by 22% to 23%. The displacement ductility ratios also meet the ductility requirements with value of 5. The hysteretic curves of three specimens are plump, and the trend of skeleton curves is basically the same. The DWPC specimens demonstrated a good energy dissipation capacity. All the specimens had shown favorable seismic performance.


2012 ◽  
Vol 517 ◽  
pp. 564-569
Author(s):  
Jin Song Fan ◽  
An Zhou ◽  
Li Hua Chen ◽  
Bing Kang Liu

Recycled concrete is a kind of new construction materials, and now received more and more attention from researchers and engineers, since its application in engineering projects can well cater to the increasing requirements of development for economic and environment-friendly society. Based on the pseudo static test of five recycled reinforcement concrete frame columns with different experimental axial compression ratios from 0.3 to 0.65, their failure modes, failure mechanism, hysteretic behavior, skeleton curves, bearing capacity, rigidity, ductility and energy dissipation capacity were discussed. Some possible influence factors and disciplines were also selected and analyzed. The study indicates that recycled reinforcement concrete frame columns in the case of relative low axial compression ratios usually exhibited similar and steady mechanical properties with common concrete columns. With the increase of axial compression ratio, its ductility and energy dissipation capacity are decreased and destruction forms tended to obvious brittle fracture, though its bearing capacity could slightly rise. The test results and analysis also manifest recycled concrete had expectative application potentials in most case.


BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6648-6667
Author(s):  
Xiaoli Han ◽  
Jian Dai ◽  
Wei Qian ◽  
Baolong Li ◽  
Yuanjun Jin ◽  
...  

The wooden columns in timber structures of ancient buildings have column foot tenons of various sizes. The main reason for these differences is their use for different roof loads. Six full-scale specimens with different sizes of column foot tenon were designed and manufactured. The tree species used for the specimens was larch. The quasi-static test was conducted on the specimens that were used in timber structures of ancient buildings. The effects of column foot tenon size on the mechanical properties of larch wooden columns were studied. The moment-rotational angle hysteretic curves, moment-rotational angle skeleton curves, ductility, stiffness degradation, energy dissipation capacity, slippages between the wooden column and the plinth, and the damage of the column foot tenons were examined. The test results showed that the column foot tenon played an important role in the mechanical behavior of the wooden column under low-cycle reversed cyclic loading. The rotation of the column foot tenon improved the energy dissipation capacity of the wooden column. As the rotational angle of the column base increased, the column foot tenon had different degrees of damage. Different sizes of column foot tenon had their own advantages and hysteretic behavior.


2019 ◽  
Vol 2019 ◽  
pp. 1-20
Author(s):  
Guofeng Xue ◽  
Wei Bao ◽  
Jin Jiang ◽  
Yongsong Shao

This study proposed a beam-to-column joint equipped with a new type of cast steel connector. The cast steel connector concentrated the primary portion of the deformation and energy dissipation of the joint and was installed with full bolted connections, rendering it a replaceable energy dissipation component and facilitating the rapid repair of the joint after an earthquake. Three full-scale specimens were fabricated and tested to investigate the hysteretic behaviors of the proposed joints under cyclic loadings. The results showed that the proposed cast steel connector exhibited reliable ductility and energy dissipation capacity. The beam-to-column joints with cast steel connectors under appropriate configuration can limit the deformation to the cast steel connector and protect the remaining joint components from plastic deformation. A more detailed finite element analysis was performed to investigate the hysteretic behavior of the joint further. The FEM results illustrated that the thickness of the vertical leg of the cast steel connector can significantly influence the stiffness and bearing capacity of the joint. Meantime, it would improve the hysteretic behavior effectively. The proposed beam-to-column joints with cast steel connectors can achieve the requirement of stiffness and load-bearing capacity and can be widely applicable in practical engineering.


2020 ◽  
pp. 136943322098273
Author(s):  
Baoxi Song ◽  
Weizhi Xu ◽  
Dongsheng Du ◽  
Shuguang Wang ◽  
Weiwei Li ◽  
...  

This paper provides a practical design method for hybrid unbonded post-tensioned precast concrete joints. Such joints featured with self-centering capacities have been widely favored in recent years. However, the absence of design methods hinders their further promotion. To solve the issue, two methods for calculating mechanical behavior of the joints were first studied: characteristic points method and iterative method. The effectiveness of the methods was verified by the existing test results. On this basis, a joint design method considering both yield bearing capacity and energy dissipation capacity was proposed. Moreover, to facilitate design, some factors affecting the bearing capacity were discussed. A five-story frame structure was designed by the proposed design method, and the influence of two design factors on structural response was analyzed by utilizing nonlinear time-history method. The analysis results show that: with the increase of energy dissipation factor αs, the post-earthquake residual deformation of the structure tends to increase linearly, while the accumulated damage of the structure will decrease continuously; both overdesign and underdesign of bearing capacity of the joint are unfavorable; and near-field earthquake may cause irreparable damage to structural columns, making the residual deformation of structures contrary to the self-centering capacity of joints, which shall be considered during engineering design.


2018 ◽  
Vol 763 ◽  
pp. 541-548 ◽  
Author(s):  
Eugene Boadi-Danquah ◽  
Duncan MacLachlan ◽  
Matthew Fadden

One approach to making modern structures more economically and environmentally sustainable is designing and constructing them to be adaptable to rapidly changing markets and building occupancies. At the same time, these structures are required to be resilient to seismic events. As a step towards meeting these goals, a lightweight, two-way, rapidly constructible and reconfigurable modular steel floor (RCRMSF) system has been developed. The system is fabricated from light-gauge steel plates sandwiching a grillage of orthogonally arranged cold formed Z-purlins, can span 9.1 m x 12.2 m, requires only girder supports, and fits within current steel construction framework. This study investigates the seismic behavior of the RCRMSF diaphragm through the use of high fidelity nonlinear finite element (FE) models. Six full-scale cantilever diaphragm models have been developed to study the effect of varying RCRMSF configurations and end support details. Both monotonic and cyclic loading protocols are used to determine the stiffness, strength, energy dissipation capacity, and general hysteretic behavior of the diaphragms. Based on the FE models, the behavior of the RCRMSF diaphragm is influenced primarily by the plate thickness and perimeter connection detail to the supporting steel frame. Overall, the RCRMSF has adequate diaphragm stiffness and strength, and shows favorable energy dissipation capacity due to its post-peak inelastic behavior. This observation implies that the RCRMSF can serve as an alternative solution to current seismic design and construction practices.


2014 ◽  
Vol 08 (04) ◽  
pp. 1450012
Author(s):  
Haozhi Tan ◽  
Liang Huang ◽  
Libo Yan ◽  
Hongwei Yi ◽  
Xin Tian

Bracing is one of the most effective systems which is widely used to improve the seismic performance of reinforced concrete (RC) plane frames. However, studies on the use of bracing in newly constructed RC space frame (RCSF) are rare. This paper presents the experimental results of two 1/4-scale, two-story, and three-bay RCSFs under cyclic loading. A RCSF without brace was designed and constructed as a control system, which was termed as "RCSF". Another one was constructed and strengthened with steel X-braces, which was termed as "SBRCSF". The seismic performance of RCSF was compared with those of SBRCSF. The test results show that compared with the RCSF, the seismic performance of the SBRCSF was improved significantly in terms of hysteresis loop, strength, stiffness degradation, and energy dissipation capacity. In addition, unlike the inter-story failure mechanism of the RCSF, the SBRCSF specimen exhibited an overall failure mechanism, which is significant for the seismic design of RCSFs. Moreover, the tested SBRCSF could bear loads in a manner similar to that of untested RCSF after the failure of the steel braces, thereby revealing the redundancy of SBRCSF and showing the advantageous of the use of steel braces for space frame.


2010 ◽  
Vol 150-151 ◽  
pp. 571-575
Author(s):  
Yun Peng Chu ◽  
Yong Yao ◽  
Shu Lian Xiao ◽  
Yue Chen

As a key part in concrete-filled steel tubular frames, the seismic behavior of joints between concrete-filled steel tubes and beams needs more research because of the complexity of stress under the reciprocating load. the behavior of 9 strengthened joints connecting concrete-filled steel tube with H-shaped steel beam have been analyzed under reversed cyclic loading condition by using finite element analysis software ANSYS, and the result show that: (1) The ultimate bearing capacity, energy dissipation capacity and ductility of strengthened joint are obvious better than that of ordinary welded joint; (2) Compared to concrete-filled steel tube the ultimate bearing capacity, energy dissipation capacity and ductility of double-layer concrete-filled steel tubes are better; (3) For the joints connecting double-layer concrete-filled steel tubes with beams, the shape of inner tube have certain effect on the ultimate bearing capacity but little on the energy dissipation capacity and ductility. (4) The shape of stiffened plate has significant influence on the ultimate bearing capacity, energy dissipation capacity and ductility of nodes.


2012 ◽  
Vol 178-181 ◽  
pp. 179-183 ◽  
Author(s):  
Yang Wen

This paper refers to currently the 1.5MW cone tube type wind-driven generator tower, design the model of the concrete-filled steel tube wind turbine tower with three limb columns, and research on the force performance, such as the change of internal force, the process of failure, hysteretic behavior, bearing capacity, ductility and energy dissipation capacity by the pseudo-static experiment on the scale model of wind turbine tower. The study shows that the P- hysteretic curve of lattice concrete-filled steel tube wind-driven generator tower with three limb columns is asymmetric, relatively full “spindle” and the phenomenon of “knead shrink” is not obvious, which account for it has good force behavior and energy dissipation capacity. This kind of tower structure, of which the reverse bearing capacity is greater than the positive, and the reverse ductility coefficient is less than the positive, indicates that it’s reverse plastic deformation ability of the tower structure is weaker than it’s positive.


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