scholarly journals Development of Novel Connections for Pre-cast Composite and Pre-cast Concrete Frames

2015 ◽  
pp. 397-404
Author(s):  
J.D Nzabonimpa ◽  
Won-Kee Hong ◽  
Seon-Chee Park ◽  
Sunkuk Kim
Keyword(s):  
Precast Concrete ◽  
Steel Plates ◽  
Structural Elements ◽  
Structural System ◽  
Concrete Frames ◽  
Structural Behaviour ◽  
Moment Connections ◽  
Composite Frame ◽  
Structural Capacity ◽  
Cast Concrete

In some applications, the conventional steel pipe racks were encased with concrete to protect the frame from fire. However, the concrete encasing steel is not considered to contribute to structural capacity at all. This paper proposed pipe rack frames encased by precast concrete, but with functions both as a part of structural elements contributing to flexural load bearing capacity and to fire proofing. The new steel-concrete composite structural system consisting of steel, concrete with reinforcements, extended steel plates with bolts designed based on inelastic finite element method provides efficient structural performances, reducing material quantities with the protection from fires. Additionally extended plate with bolts introduced for column-beam joint assembly played important roles in providing moment connections. AISC 358 introduced the use of extended plate similar to the proposed connection. Significant experimental and analytical investigations were performed to verify structural behaviour of the composite frame. Material quantities were also compared to demonstrate economy of the new frames compared with conventional pipe rack frames.

Nonlinear modelling and seismic behaviour of precast concrete structures with steel shear walls

2016 ◽  
Vol 49 (4) ◽  
pp. 293-304
Author(s):  
Farhad Behnamfar ◽  
Rafeek Artoonian ◽  
Mehdi Ghandil
Keyword(s):  
Precast Concrete ◽  
Shear Walls ◽  
Structural System ◽  
Concrete Frames ◽  
Seismic Behaviour ◽  
Fem Model ◽  
Shell Elements ◽  
Connection Type ◽  
Nonlinear Static ◽  
Good Agreement

A new structural system consisting of precast concrete frames and steel shear walls (SSW's) is introduced and studied numerically in this paper. Two different models, first using ''exact'' FEM and second using approximate equivalent strip model (ESM), are utilized for analysis of such a system with nonlinear static (pushover) procedure. In the FEM model use is made of shell elements while the ESM benefits from simple links that replace the wall panels in the model and are oriented such that they work in tension. Because of good agreement observed between the results of the models in smaller structures, for taller buildings only the ESM approach is followed where computationally applying the FEM approach is impractical. The lateral behaviour of the systems under consideration is investigated with regard to parameters such as number of stories and beam-column connection type. As a result, the ductility, overstrength and response modification factors are calculated for this new structural system as quantities required for their practical design.

scholarly journals Steel Beam-Column Joint with Discontinuous Vertical Reinforcing Bars

2015 ◽  
pp. 197-204
Author(s):  
Ju-Yun Hu ◽  
Won-Kee Hong ◽  
Seon-Chee Park ◽  
Jisoon Kim
Keyword(s):  
Load Transfer ◽  
Precast Concrete ◽  
Steel Plates ◽  
Steel Beam ◽  
Test Results ◽  
Reinforcing Bars ◽  
Concrete Frames ◽  
Steel Members ◽  
Column Joint ◽  
In Parenthesis

The authors proposed steel beam-column connections for precast concrete frames in previous studies. The steel-concrete composite frames provided fast assembly time as steels with economy of concrete structures. However, when enough space is not available at column-beam joints steel sections from beams cannot be connected with column brackets. This paper suggests that some vertical reinforcing bars are disconnected at joints by connecting vertical steel reinforcements to steel plates placed above and below column steels to provide load transferring path. Loads from re-bars are transferred to steel plates, column steels and back to steel plates and re-bars below column steels. Re-bars connected to steel plates by bolts at above and below column steel are discontinued at joint to provide spaces for connections between column brackets and beam steels. Extensive experiments were performed to verify load transfer from re-bars to steel plates above joints and steel plates to re-bars below joint. The flexural load bearing capacity of a column with total of 24 vertical re-bars were compared to columns with discontinuous re-bars at joints. The number of discontinuous re-bars at joint used in column specimen was 0 (0.0%), 4 (16.7%), 12 (50.0%), and 20 (83.3%). The numbers in parenthesis are the percentages of discontinuous rebars to the total number of vertical re-bars of control column. Experiments showed how loads from vertical steel reinforcements that were cut off at joints were transferred to steel plate. The test results also demonstrated that a part of flexural capacities were reduced for specimen with discontinuous vertical re-bars. The reduction of 6.0 %, 13.7% and 54.0% of flexural capacities were observed for columns with 4 (16.7%), 12 (50.0%) and 20 (83.3%) discontinuous vertical rebars, respectively. The test results can be used to design vertical reinforcing bars and column joints that can provide space for column brackets to which steel members of beams are connected.

scholarly journals Steel beam–column joint with discontinuous vertical reinforcing bars

2017 ◽  
Vol 23 (4) ◽  
pp. 440-454 ◽  
Author(s):  
Ju-Yun HU ◽  
Won-Kee HONG
Keyword(s):  
Load Transfer ◽  
Low Cost ◽  
Precast Concrete ◽  
Steel Plates ◽  
Steel Beam ◽  
Reinforcing Bars ◽  
Concrete Frames ◽  
Transfer Path ◽  
Composite Frames ◽  
Column Joint

The authors have previously proposed steel beam–column connections for precast concrete frames. The steel–concrete composite frames combined the advantages of the fast assembly of steel and the low cost of concrete structures. However, when not enough space is available at column–beam joints, steel sections from beams cannot be connected with column brackets. To address this issue, this paper explores the strategy of disconnecting some vertical reinforcing bars at the joints by connecting vertical steel reinforcements to steel plates placed above and below column steels, to provide a load transfer path. Loads from re-bars are transferred to steel plates, column steels, and back to steel plates and re-bars below the column steels. This strategy provided space for beam–column joints of composite frames. Extensive experiments were performed to verify load transfer from re-bars to steel plates above joints and from the steel plates to re-bars below the joint. The flexural load-bearing capacity of a column with a total of 24 vertical re-bars was compared to that of columns with discontinuous re-bars at the joints; the number of discontinuous re-bars at the joint used in the column specimens tested was 0 (0.0%), 4 (16.7%), 12 (50.0%), and 20 (83.3%).

Behavior of HPFRC Connections for Precast Concrete Frames Under Reversed Cyclic Loading

PCI Journal ◽  
1998 ◽  
Vol 43 (6) ◽  
pp. 58-71 ◽  
Author(s):  
Rosa M. Vasconez ◽  
Antoine E. Naaman ◽  
James K. Wight
Keyword(s):  
Cyclic Loading ◽  
Precast Concrete ◽  
Concrete Frames ◽  
Reversed Cyclic Loading ◽  
Reversed Cyclic

scholarly journals Parametric Analysis of the Shear Lag Effect in Tube Structural Systems of Tall Buildings

2020 ◽  
Vol 11 (1) ◽  
pp. 278
Author(s):  
Ivan Hafner ◽  
Anđelko Vlašić ◽  
Tomislav Kišiček ◽  
Tvrtko Renić
Keyword(s):  
Parametric Analysis ◽  
Numerical Models ◽  
Tall Buildings ◽  
Structural Systems ◽  
Structural Elements ◽  
Structural System ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Lag Effect ◽  
Secondary Structural Elements

Horizontal loads such as earthquake and wind are considered dominant loads for the design of tall buildings. One of the most efficient structural systems in this regard is the tube structural system. Even though such systems have a high resistance when it comes to horizontal loads, the shear lag effect that is characterized by an incomplete and uneven activation of vertical elements may cause a series of problems such as the deformation of internal panels and secondary structural elements, which cumulatively grow with the height of the building. In this paper, the shear lag effect in a typical tube structure will be observed and analyzed on a series of different numerical models. A parametric analysis will be conducted with a great number of variations in the structural elements and building layout, for the purpose of giving recommendations for an optimal design of a tube structural system.

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