scholarly journals An Experimental Study on the Flexural Behavior of Precast Concrete Modular Beam Systems Using Inserted Steel Plates

2021 ◽  
Vol 11 (9) ◽  
pp. 3931
Author(s):  
Kyong-Min Ro ◽  
Min-Sook Kim ◽  
Chang-Geun Cho ◽  
Young-Hak Lee

Recently, interest in using precast concrete (PC) modules has increased due to their better seismic performance than steel modules. However, they must be joined by additional elements to ensure structural integration between the modules. The essential aim of the precast concrete module is to ensure structural performance with appropriate connection methods. However, the technical problem of connecting PC modules still needs to be improved. This study proposed a PC modular beam system for improved structural and splicing performance, and simple construction. This modular system consisted of modules with steel plates inserted to improve integrity of modules, ease of construction, and low cost. The structural performance of the proposed PC modular beam system was evaluated by flexural test on one reinforced concrete (RC) beam specimen consisting of a monolithic beam, and two PC specimens with the proposed modular system. The results demonstrated that the proposed PC modular beam system achieved approximately 80% of the structural performance compared to the monolithic specimen, with approximately 1.3-fold greater ductility.

2021 ◽  
Vol 11 (24) ◽  
pp. 12110
Author(s):  
Kyong Min Ro ◽  
Min Sook Kim ◽  
Chang Geun Cho ◽  
Young Hak Lee

In modular structures, prefabricated modular units are joined at the construction site. Modular structures must ensure splicing performance by connecting modular units sufficiently. The bolted connection using steel plates may suffer from alignment issues and corrosion problems. In a precast concrete (PC) modular system, there is difficulty grouting the sleeves when splicing reinforcing bars. This study proposed a PC modular beam using a bolted connecting plate to deal with issues in typical steel modules and PC modules. The structural performance was evaluated by flexural and shear tests on two monolithic beams and two proposed PC specimens. The test results showed that the structural performance of the PC modular specimen was 88% of that of the monolithic reinforced concrete (RC) beam specimen and 102% of the strength calculated by ACI 318-19. Therefore, the proposed PC modular system using bolted connecting plates can solve the problems observed in typical steel and PC modules and improve the structural performance.


Author(s):  
Jang-Woon Baek ◽  
Su-Min Kang ◽  
Tae-Ho Kim ◽  
Jin-Yong Kim

AbstractRecently, as a new precast concrete (PC) construction method for increasing economy and constructability, the PC double-beam system has been developed for factories or logistic centers, where construction duration is particularly important. In this study, half-scaled PC double beam–column connection was tested under gravity loading and cyclic lateral loading. The major test parameters included the use of the spliced PC column and the addition of reinforcement at the beam–column joint. In the gravity loading test, the flexural behavior of the PC double beam was investigated. The test results showed satisfactory flexural capacity at the PC double-beam section, validating the composite action between the PC and RC members. In the cyclic lateral loading test, the seismic performance of the PC double beam–column connection was investigated. Based on the test results, the failure mode, load-carrying capacity, deformation capacity, energy dissipation capacity, secant stiffness, and shear strength of the PC double-beam system were evaluated and compared with those of a conventional RC double beam–column connection. According to the test results, the structural performance of the PC double beam–column connection was comparable to that of the RC double beam–column connection and satisfied the acceptance criteria of moment frame in the ACI 374.1-05 provision.


2019 ◽  
Vol 9 (22) ◽  
pp. 4946 ◽  
Author(s):  
Sun-Jin Han ◽  
Jae-Hoon Jeong ◽  
Hyo-Eun Joo ◽  
Seung-Ho Choi ◽  
Seokdong Choi ◽  
...  

Half precast concrete slabs with inverted multi-ribs (Joint Advanced Slab, JAS), which enhance composite performance between slabs by introducing shear keys at connections between the slabs and improve structural performance by placing prestressing tendons and truss-type shear reinforcements, have recently been developed and applied in many construction fields. In this study, flexural and shear tests were performed to verify the structural performance of JAS members. Towards this end, two flexural specimens and four shear specimens were fabricated, and the presence of cast-in-place concrete and the location of the critical section were set as the main test variables. In addition, the flexural and shear performance of the JAS was quantitatively evaluated using a non-linear flexural analysis model and current structural design codes. Evaluation results confirmed that the flexural behavior of the JAS was almost similar to the behavior simulated through the non-linear flexural analysis model, and the shear performance of the JAS can also be estimated appropriately by using the shear strength equations presented in the current design codes. For the JAS with cast-in-place concrete, however, the shear strength estimation results differed significantly depending on the way that the shear contributions of the precast concrete unit and cast-in-place concrete were calculated. Based on the analysis results, this study proposed a design method that can reasonably estimate the shear strength of the composite JAS.


2017 ◽  
Vol 23 (4) ◽  
pp. 440-454 ◽  
Author(s):  
Ju-Yun HU ◽  
Won-Kee HONG

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%).


PCI Journal ◽  
2008 ◽  
Vol 53 (4) ◽  
pp. 62-82 ◽  
Author(s):  
Nabil Grace ◽  
Tsuyoshi Enomoto ◽  
Ahmed Abdel-Mohti ◽  
Yahia Tokal ◽  
Sreejith Puravankara

2021 ◽  
Vol 11 (2) ◽  
pp. 506
Author(s):  
Sun-Jin Han ◽  
Inwook Heo ◽  
Jae-Hyun Kim ◽  
Kang Su Kim ◽  
Young-Hun Oh

In this study, experiments and numerical analyses were carried out to examine the flexural and shear performance of a double composite wall (DCW) manufactured using a precast concrete (PC) method. One flexural specimen and three shear specimens were fabricated, and the effect of the bolts used for the assembly of the PC panels on the shear strength of the DCW was investigated. The failure mode, flexural and shear behavior, and composite behavior of the PC panel and cast-in-place (CIP) concrete were analyzed in detail, and the behavioral characteristics of the DCW were clearly identified by comparing the results of tests with those obtained from a non-linear flexural analysis and finite element analysis. Based on the test and analysis results, this study proposed a practical equation for reasonably estimating the shear strength of a DCW section composed of PC, CIP concrete, and bolts utilizing the current code equations.


2019 ◽  
Vol 253 ◽  
pp. 02004
Author(s):  
Wael Alnahhal ◽  
Omar Aljidda

This study investigates the effect of using different volume fractions of basalt macro fibers (BMF) on the flexural behavior of concrete beams made with 100% recycled concrete aggregates (RCA) experimentally. A total of 4 reinforced concrete (RC) beam specimens were flexural tested until failure. The parameter investigated included the BMF volume fraction (0%, 0.5%, 1%, and 1.5%). The testing results of the specimens were compared to control beam specimen made with no added fibers. The experimental results showed that adding BMF improves the flexural capacity of the tested beams.


Author(s):  
Philipp Andreazza ◽  
Andreas Gericke ◽  
Knuth-Michael Henkel

AbstractArc brazing with low-melting copper-based filler materials, which has long been established and standardized in the thin sheet sector, offers numerous advantages in the processing of predominantly electrolytically galvanized steel structures. In steel and shipbuilding, on the other hand, equipment parts made of thick steel sheets are hot-dip galvanized at low cost and with good corrosion-inhibiting properties. Quality welding of such constructions is not possible without special precautions such as removing the zinc layer and subsequent recoating. With regard to greater plate thicknesses, arc brazing was analyzed in these investigations as an alternative joining method with regard to its suitability for practical use. Within the scope of the investigations, CuSi3Mn, CuMn12Ni2, and four different aluminum bronzes were examined on different sheet surface conditions with regard to the geometrical and production parameters. This was carried out by build-up and connection brazing, executed as butt and cross joints. Quasi-static tensile tests and fatigue tests were used to assess the strength behavior. In addition, metallographic analyses are carried out as well as hardness tests. The suitability for multi-layer brazing and the tendency to distortion were also investigated, as well as the behavior of arc brazed joints under corrosive conditions.


2005 ◽  
Vol 8 (3) ◽  
pp. 247-257 ◽  
Author(s):  
Y. Fukumoto ◽  
T. Takaku ◽  
T. Aoki ◽  
K. A. S. Susantha

This paper presents the innovative use of hot-rolled thickness-tapered mill products, longitudinally profiled (LP) plates, for the seismic performance of bridge bents of single and portal framed piers. The study involves the inelastic cyclic testing and numerical analysis of tested beam-columns and portal frames in order to evaluate the effects of tapering ratios of LP plates, penetration of yielding, and number of locally buckled panels on their structural ductility. A structural design method is proposed for the portal frames having LP panels under cyclic loadings.


2007 ◽  
Vol 34 (7) ◽  
pp. 885-889 ◽  
Author(s):  
H El Naggar ◽  
E N Allouche ◽  
M H. El Naggar

Concrete pipes represent the backbone of the municipal storm and wastewater collection systems of Ontario, Canada. Industry and academia partnered on a research effort that aimed at developing new precast-concrete pipe products that provide added value to the final user in comparison with existing products. This paper describes a full-scale experimental evaluation of the design, manufacturing, and performance aspects of a "cellular" concrete pipe, a precast concrete pipe in which multiple continuous conduits were incorporated within its wall. Two fully-instrumented prototype segments of the proposed cellular concrete pipe were manufactured using standard dry-cast manufacturing procedures. The pipe segments were subjected to a D-load test to evaluate their structural performance. The observed structural performance was found to be comparable to solid-wall specimens, particularly when a four-conduit configuration was used. Of the six materials used as conduits, PVC and aluminum were found to perform the best. The presence of the conduits appears to delay the on-set of major cracks, thus increasing the D-load value. Key words: precast, concrete, pipe, experimental, conduit system, trenchless construction methods.


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