scholarly journals Experimental Study of a New Precast Prestressed Concrete Joint

2018 ◽  
Vol 8 (10) ◽  
pp. 1871 ◽  
Author(s):  
Xueyuan Yan ◽  
Suguo Wang ◽  
Canling Huang ◽  
Ai Qi ◽  
Chao Hong

Precast monolithic structures are increasingly applied in construction. Such a structure has a performance somewhere between that of a pure precast structure and that of a cast-in-place structure. A precast concrete frame structure is one of the most common prefabricated structural systems. The post-pouring joint is important for controlling the seismic performance of the entire precast monolithic frame structure. This paper investigated the joints of a precast prestressed concrete frame structure. A reversed cyclic loading test was carried out on two precast prestressed concrete beam–column joints that were fabricated with two different concrete strengths in the keyway area. This testing was also performed on a cast-in-place reinforced concrete joint for comparison. The phenomena such as joint crack development, yielding, and ultimate damage were observed, and the seismic performance of the proposed precast prestressed concrete joint was determined. The results showed that the precast prestressed concrete joint and the cast-in-place joint had a similar failure mode. The stiffness, bearing capacity, ductility, and energy dissipation were comparable. The hysteresis curves were full and showed that the joints had good energy dissipation. The presence of prestressing tendons limited the development of cracks in the precast beams. The concrete strength of the keyway area had little effect on the seismic performance of the precast prestressed concrete joints. The precast prestressed concrete joints had a seismic performance that was comparable to the equivalent monolithic system.

2018 ◽  
Vol 21 (12) ◽  
pp. 1895-1910 ◽  
Author(s):  
Jianyang Xue ◽  
Xin Zhang ◽  
Rui Ren ◽  
Lei Zhai ◽  
Linlin Ma

This article mainly focused on the seismic performance of steel reinforced recycled concrete frame structure under low-cyclic reversed loading. To evaluate seismic performance of steel reinforced recycled concrete frame structure, a two-span three-storied steel reinforced recycled concrete frame was conducted at civil engineering laboratory of Xi’an University of Architecture and Technology. Experimental and numerical studies were implemented to investigate the crack status, failure modes, hysteresis loops, skeleton curves, energy dissipation capacity, load–displacement curves, P-Δ effect, and the influence of recycled concrete strength under low-cyclic reversed loading. Results indicate that the steel reinforced recycled concrete frame structure has good seismic behavior during test, and the spindle-shaped hysteresis loops illustrate that the frame has relatively high energy dissipation capacities. The design of steel reinforced recycled concrete frame satisfied the requirements of strong column weak beam, strong shear weak bending, and strong joint weak components. Finally, the simulated results obtained by OpenSees software agree well with the test, which verify the rationality and reliability of the proposed model. The conclusions of this article will be helpful for the design of steel reinforced recycled concrete structures in seismic regions.


Author(s):  
Xiandong Liao ◽  
Xiang Hu

The seismic performance of the internal connection of precast prestressed concrete frame was studied systematically, based on the experiment of full-scale model under low cyclic reversed loading. This study was mainly focused on failure pattern, load-carrying capacity, skeleton curves, and hysteresis curves. Furthermore, a nonlinear finite element analysis using Abaqus was carried out to study the characteristics of the internal connection of precast prestressed concrete frame. Results revealed that the damage was concentrated mainly on beam end owing to flexural action, while steel bars in the columns and stirrups in the core region remained elastic until failure occurred. The calculated value of the load-carrying capacity of the internal connection was similar to the experimental one. Present study can be referenced for the application of precast prestressed concrete frame in high seismic zones.


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.


2020 ◽  
Vol 10 (5) ◽  
pp. 1749
Author(s):  
Seung-Ho Choi ◽  
Jin-Ha Hwang ◽  
Sun-Jin Han ◽  
Hyo-Eun Joo ◽  
Hyun-Do Yun ◽  
...  

In recent years, a variety of strengthening methods have been developed to improve the seismic performance of reinforced concrete (RC) frame structures with non-seismic details. In this regard, this study proposes a new type of seismic strengthening method that compresses prefabricated precast concrete (PC) walls from the outside of a building. In order to verify the proposed method, a RC frame structure strengthened with precast walls was fabricated, and cyclic loading tests were performed. The results showed that specimens strengthened using the proposed method exhibited further improvements in strength, stiffness and energy dissipation capacity, compared to RC frame structures with non-seismic details. In addition, a nonlinear analysis method, capable of considering the flexural compression and shear behaviors of the walls, was suggested to analytically evaluate the structural behavior of the frame structures strengthened by the proposed method. Using this, an analysis model for frame structures strengthened with precast walls was proposed. Through the proposed model, the analysis and test results were compared in relation to stiffness, strength, and energy dissipation capacity. Then, the failure mode of the column was evaluated based on the pushover analysis. In addition, this study proposed a simplified analysis model that considered the placement of longitudinal reinforcements in shear walls.


2008 ◽  
Vol 400-402 ◽  
pp. 893-899 ◽  
Author(s):  
Jian Guo Cai ◽  
Jian Feng ◽  
Hong Jin Zhu ◽  
Ya Fei Liu ◽  
Li Feng Huang

An experimental investigation was undertaken into the seismic performance of a precast prestressed concrete frame system. A total of three beam-to-column connection models were designed, built, and tested to failure to evaluate their strength and ductility properties under cyclic loading. The comparative study showed that the hysteretic loops were full and the joints had better energy dissipation capacity. It was concluded that satisfactory seismic performance could be expected from this frame system if the slip of the U-shaped reinforcing steel bar was controlled well on the zone of joint. Then the finite element method (FEM) was used to analyze the specimen and the calculation results were in good agreement with those of the test.


Author(s):  
Yadong Li ◽  
Fangfang Geng ◽  
Youliang Ding ◽  
Libin Wang

The self-centering precast concrete frame structure combines the advantages of industrialization and low earthquake damage, and its energy dissipation capacity and seismic performance have always been the focus of research. This paper proposed a kind of self-centering precast concrete frame with hysteretic dampers (SCPCHD). Its modular design makes the energy dissipation device and components easy to repair and replace. In order to obtain the optimal design, the finite element models of SCPCHD frames with different layout types of post-tensioned (PT) tendons and different shapes of hysteretic dampers are established, and the elastoplastic dynamic time-history analyses are carried out. The results show that the layout types and vertical margin of PT tendons have little effect on the displacement response of the frame structure. Compared to linear PT tendons, polygonal PT tendons can better bear the bending moment of the beam and reduce the stress of longitudinal reinforcements in the beam. The reduce effect of shortening the vertical margin on the tensile damage of beam concrete is obvious in the frame with polygonal PT tendons, but not obvious in the frame with linear PT tendons. Rational design of the prestressing force also plays a crucial role in the energy dissipation capacity of SCPCHD frames.


2013 ◽  
Vol 353-356 ◽  
pp. 1879-1882
Author(s):  
Yi Xiang Xu ◽  
Wen Pan ◽  
Sheng Lan Zhu

The multi-storey reinforced concrete frame structure whose frame has been added with a kind of unsymmetrical K-type friction energy dissipation brace is taken as an example in this article. The time history analysis of different angles of unsymmetrical K-type friction energy dissipation brace and symmetrical K-type friction energy dissipation brace under the rare earthquake has been done by using the finite element software SAP2000. The analysis and comparison on the seismic performance shows that symmetrical K-type friction energy dissipation brace under certain conditions. Plan layout could be more flexible by using the result obtained which could become a reference for design in days to come.


2012 ◽  
Vol 626 ◽  
pp. 85-89 ◽  
Author(s):  
Kay Dora Abdul Ghani ◽  
Nor Hayati Hamid

The experimental work on two full-scale precast concrete beam-column corner joints with corbels was carried out and their seismic performance was examined. The first specimen was constructed without steel fiber, while second specimen was constructed by mixed up steel fiber with concrete and placed it at the corbels area. The specimen were tested under reversible lateral cyclic loading up to ±1.5% drift. The experimental results showed that for the first specimen, the cracks start to occur at +0.5% drifts with spalling of concrete and major cracks were observed at corbel while for the second specimen, the initial cracks were observed at +0.75% with no damage at corbel. In this study, it can be concluded that precast beam-column joint without steel fiber has better ductility and stiffness than precast beam-column joint with steel fiber. However, precast beam-column joint with steel fiber has better energy dissipation and fewer cracks at corbel as compared to precast beam-column joint without steel fiber.


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