scholarly journals Structural Performance of a Precast Concrete Modular Beam Using Bolted Connecting Plates

2021 ◽  
Vol 11 (24) ◽  
pp. 12110
Author(s):  
Kyong Min Ro ◽  
Min Sook Kim ◽  
Chang Geun Cho ◽  
Young Hak Lee
Keyword(s):  
Precast Concrete ◽  
Steel Plates ◽  
Structural Performance ◽  
Modular System ◽  
Beam Specimen ◽  
Test Results ◽  
Reinforcing Bars ◽  
Bolted Connection ◽  
Modular Units ◽  
Modular Structures

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.

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
Keyword(s):  
Low Cost ◽  
Precast Concrete ◽  
Technical Problem ◽  
Steel Plates ◽  
Flexural Behavior ◽  
Structural Performance ◽  
Modular System ◽  
Beam Specimen ◽  
Structural Integration ◽  
Beam System

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.

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.

STRUCTURAL PERFORMANCE OF DAMAGED OPEN-WEB TYPE SRC BEAM-COLUMNS WITH BOLT-CONNECTED BATTEN STEEL PLATES AFTER RETROFITTING

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Takahiro Kume ◽  
Takashi Fujinaga ◽  
Yuping Sun
Keyword(s):  
Axial Load ◽  
Steel Plates ◽  
Analytical Models ◽  
Structural Performance ◽  
Test Results ◽  
Beam Columns ◽  
Cyclic Lateral Load ◽  
Load Carrying ◽  
Lower Load ◽  
Constant Axial Load

In this paper, structural performance of damaged SRC beam-columns with open-web type of batten steel plate after retrofitting was investigated. Three open-web type SRC beam-columns with bolt-connected batten steel plates were fabricated and tested under combined constant axial load and cyclic lateral load. At first, each beam-column was　cyclically loaded to the targeted displacement. After the first loading, the test columns were retrofitted and reloaded till large deformation or failure. The damaged portion of each column was retrofitted with the polymer cement mortar and epoxy resin was injected into the cracks. The measured stiffness of retrofitted columns varied between 71.4% and 85.5% of the initial one. And, test results also indicated that the column which experienced the larger displacement and higher axial load showed lower load carrying capacity, but the others showed approximately the same capacities as the initial columns. Numerical analysis was also conducted to explain the retrofitted columns. Analytical results predicted the experimental behavior fairly well, which verifies the validity of the analytical models in low axial load.

Rotational Behavior of Bolted Glulam Beam-to-Column Connections Reinforced with Section Steel

2016 ◽  
Vol 858 ◽  
pp. 15-21 ◽  
Author(s):  
Yu Rong Ma ◽  
Xiao Bin Song ◽  
Tian Qi Xu ◽  
Lie Luo
Keyword(s):  
Brittle Failure ◽  
Steel Plates ◽  
Rotational Behavior ◽  
Timber Structures ◽  
Test Results ◽  
Average Increase ◽  
Bolted Connection ◽  
New Type ◽  
Ductility Ratio ◽  
Bending Failure

Bolted connections with slotted-in steel plates are commonly used to connect beams and columns in heavy timber structures. While due to the low tensile strength of wood in the perpendicular-to-grain direction, these connections are usually not able to present satisfying rotational performance. In order to solve this problem, a relatively new type of bolted connection, reinforced with section steel, was designed and tested in this paper. Two groups of total six specimens were tested under monotonic loading to investigate their rotational behavior. Tests showed that the brittle failure mode of wood splitting in the perpendicular-to-grain direction was fully restrained. Only slight cracks were observed in most specimens, except one that underwent bending failure in the beam member. Test results indicated an average increase of 78.7% in moment resistance and a 54.8% increase in ductility ratio for middle-storey connections, compared with conventional connections simply using slotted-in steel plates. Top-storey connections, without previous test results as comparison, also presented high moment-bearing capacity and reliable deformability. As a result, such connection may receive a broad application, especially in multi-storey heavy timber structures.

scholarly journals Evaluation of the Structural Performance of a Novel Methodology for Connecting Modular Units Using Straight and Cross-Shaped Connector Plates in Modular Buildings

2020 ◽  
Vol 10 (22) ◽  
pp. 8186
Author(s):  
Sang-Sup Lee ◽  
Keum-Sung Park ◽  
Ju-Seong Jung ◽  
Kang-Seok Lee
Keyword(s):  
Longitudinal Direction ◽  
Structural Performance ◽  
Building Structures ◽  
Drift Angle ◽  
Modular Units ◽  
Strength Capacity ◽  
Story Drift ◽  
Modular Buildings ◽  
Cyclic Loading Tests ◽  
Modular Structures

The strength capacity of modular buildings is determined by the weakest part, and connections between modular units are often weaker than the modular units themselves. Thus, to verify the safety of modular structures, the structural performance of connections between modular units should be evaluated; the practical suitability of connection methods under a range of construction conditions should also be determined. In conventional modular building structures, modular units are generally connected using bolts between connector plates, interlocking devices, or steel plate welding. However, current methods are not technically or practically suitable for all types of modular buildings, such as high-rise modular buildings. Here, we describe a novel technology for connecting modular units to ensure the safety of modular structures. In this study, straight and cross-shaped metal connectors that use rectangular tubular columns and channel beams were proposed for connecting modules. Their structural performance was evaluated through cyclic loading tests by controlling the story drift angle in the width and longitudinal directions. The experimental results demonstrated that all specimens exhibited relatively stable behavior up to a drift angle of 0.04 rad, and there was a superior response in terms of energy absorption capability in the longitudinal direction results compared to the width direction. However, in comparison to the cross-shaped connector plate, the stiffness of the straight connector plate decreased as the drift angle of the column increased.

scholarly journals Hysteretic Response of Tilt-Up Concrete Precast Walls with Embedded Steel Plate Connections

2020 ◽  
Vol 12 (19) ◽  
pp. 7907
Author(s):  
Hyun-Do Yun ◽  
Hye-Ran Kim ◽  
Won-Chang Choi
Keyword(s):  
Prestressed Concrete ◽  
Structural Integrity ◽  
Precast Concrete ◽  
American Concrete Institute ◽  
Steel Plates ◽  
Test Results ◽  
Wall Panel ◽  
Concrete Wall ◽  
Concrete Panels ◽  
Wall Panels

Many connection systems are available that can transfer tension and shear loads from a precast concrete wall panel to a floor slab. However, due to the insufficient anchor depth in relatively thin precast concrete panels, it is difficult to attain adequate ductility and stiffness to ensure structural integrity. Based on the authors’ previous research results, the supplementary reinforcement of embedded steel plates in precast concrete wall panels can enhance stiffness while maintaining allowable displacement and ductility. In this study, three full-size tilt-up precast concrete panels with embedded steel plates were fabricated. Lateral cyclic loads were applied to full support structures consisting of a precast concrete wall panel and a foundation. The test results were compared with the results predicted using existing code equations found in the American Concrete Institute 318-14 and the Prestressed Concrete Institute Handbooks. The test results confirm that the supplementary reinforcement of thin precast concrete wall panels can provide (i) the required strength based on current code equations, (ii) sufficient ductility, and (iii) the energy dissipation capacity to resist cyclic loading.

scholarly journals Structural Performance of PC Double Beam–Column Connection Under Gravity and Seismic Loading

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Jang-Woon Baek ◽  
Su-Min Kang ◽  
Tae-Ho Kim ◽  
Jin-Yong Kim
Keyword(s):  
Precast Concrete ◽  
Lateral Loading ◽  
Flexural Behavior ◽  
Structural Performance ◽  
Test Results ◽  
Moment Frame ◽  
Loading Test ◽  
Beam System ◽  
Double Beam ◽  
Secant Stiffness

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.

Experimental Study on CFRP-Bonded Steel Plates with Thickness Reduction Using Underwater Epoxy

2011 ◽  
Vol 117-119 ◽  
pp. 373-379
Author(s):  
Xiao Chen ◽  
Yasuo Kitane ◽  
Yoshito Itoh
Keyword(s):  
Epoxy Adhesive ◽  
Steel Plates ◽  
Fiber Reinforced Polymer ◽  
Structural Performance ◽  
Carbon Fiber Reinforced Polymer ◽  
Curing Process ◽  
Test Results ◽  
Initial Stiffness ◽  
Reinforced Polymer ◽  
Loading Tests

This paper presents a series of uniaxial loading tests on the thickness-reduced steel plates bonded with carbon fiber reinforced polymer (CFRP) strand sheets using underwater epoxy as adhesive. Four sets of material test are carried out on epoxy coupons at different curing times. Repaired performance of CFRP-bonded steel plates is investigated in terms of initial stiffness, yield strength, and failure mode of the specimens. Test results showed that the structural performance of CFRP-bonded steel plates does not reach the expected design level due to a slow curing process of epoxy adhesive in this study. The curing effects of epoxy adhesive on the repaired performance are discussed.

EXPERIMENTAL AND NUMERICAL STUDIES OF STRUCTURAL PERFORMANCE OF NOTCH DAMAGED STEEL BEAMS

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Said Elkholy ◽  
Bilal El-Ariss
Keyword(s):  
Three Dimensional ◽  
Structural Performance ◽  
Steel Beams ◽  
Beam Specimen ◽  
Test Results ◽  
Numerical Studies ◽  
Bare Steel ◽  
Three Dimensional Models ◽  
Good Agreement ◽  
Opening Width

Performance of notch damaged unrepaired steel I-shaped beam specimens was examined experimentally and numerically simulated using finite element modeling. Nine U-shaped notch damaged specimens and one control beam specimen were considered. The nine unrepaired laterally unsupported I-shaped full-scale steel specimens were tested in two-point loadings and the parameters considered in the study were the size and location of the notch. The notch size was 30 mm, 40 mm, and 60 mm in depth with a constant opening width of 20 mm. The location of the notch was at one-quarter, one third, and middle of the specimen clear span. All pre-damaged specimens had notches on one side of the tension flange with respect to the beam web except for two specimens where two notches were cut at the middle of the specimen clear span on both sides of the tension flange. The test specimens were modeled analytically using three-dimensional models of the bare-steel I-shaped specimens for comparison of the analytical predictions with experimental results. The test results showed the strength of the notched beams was hardly affected by the notch size or location. However, the stiffness of the beams was slightly decreased as the notch got closer to the mid-span with increased ductility. The corresponding analytical results were in good agreement with the test data.

Bending and Shear Strength of I-Slab with Polystyrene Forms

2008 ◽  
Vol 385-387 ◽  
pp. 353-356 ◽  
Author(s):  
Seung Hun Kim ◽  
K.K. Lee ◽  
Han Seung Lee ◽  
K.J. Lee ◽  
In Seok Kang
Keyword(s):  
Precast Concrete ◽  
The Self ◽  
Punching Shear ◽  
Structural Performance ◽  
Displacement Curve ◽  
Test Results ◽  
Construction Period ◽  
Experimental Works ◽  
Concrete Deck

Where the self weight of the overall slab needs to be considered, the quantity of in-situ concrete required can be reduced by the introduction of polystyrene void forms supplied and fixed to the precast panel during manufacture. In this study, new I-slab system with polystyrene form and precast concrete deck is proposed to reduce the construction period and the self weight of the slab. This paper presents experimental works on the bending and shear of the I-slabs. Five specimens were tested. The main parameters of experiments were the hole diameter of polystyrene form and the thickness of slab. Structural performance of I-slab was evaluated on the basis of failure mode, load-displacement curve, and ultimate strengths. Based on the test results, the critical punching shear sections were changed as test variables, so the punching shear strengths were very different. Test results indicated that the developed I-slab were very effective to increase the strength because of self weight reduction.

Sign in / Sign up

Export Citation Format

Share Document