• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.706-711
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• 1998

Structural tests of the PSC Beam bridge using high strength concrete, concrete compressive strength 700kg/$\textrm{cm}^2$, are conducted for the application including durability and serviceability of the bridge. Current design safety factors with respect to the jacking force and the service design load DB-24 are applied to the design of the bridge. Concrete compressive strength 700kg/$\textrm{cm}^2$, girder depth 2.3m, girder space 3.2m, span length 20m, and slab thickness 27cm are selected for the bridge test. The Bulb-Tee section of the girders is applied instead of I section because it is well known more stable to the longer span(40m). Static load test(4 beams) with composite and non-composite section, and fatigue load test(1 beams) with composite section are conducted. Crack moment, ultimate load, deflections with load steps, and strains of the beam section for those bridges are investigated. The structural test results of the bridges showed a good performance for a safety and a serviceability.

• Steel and Composite Structures
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• v.42 no.5
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• pp.671-683
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• 2022

To investigate and predict the long-term time-dependent behavior, such as creep, shrinkage, and relaxation of PS strands, and prestress loss in prestressed steel-concrete composite beams, named Precom, full-scale tests were conducted and the collected data were compared with those obtained from the two proposed analytical models. The combined effective modulus method (EMM)-empirical model proposed with a flowchart considered the creep effect to determine the prestress loss. Conversely, the age-adjusted effective modulus method (AEMM) with CEB-FIP equation was developed to account for the concrete aging. The results indicated that the AEMM with CEB-FIP model predicts the long-term behavior of Precom effectively.

• Magazine of the Korea Concrete Institute
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• v.9 no.3
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• pp.137-147
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• 1997

Interface shear strength of' concrete under static loading and deterioratiion of interface strength by fatigue loading in shear were experimentally investigated using composite beam test specimens. Thirteen beams were constructed. Five composite beams were tested statically until interface delaminations were observed in the static tests. Seven composite beam and one monolithically cast beam were subjected to two to three million cycles of fatigue load. Test variables were interface roughness, interface shear reinforcement, and presence of interface bond. The average interface shear strength of the composite beams with bonded-rough interface was 6, 060 kPa. No interface delamination was observed after cycling for the composite beams with bonded - rough interface and interface bond was not influenced by repeated application of the shear stress of 2.000 kPa(about 1/3 of the static interface shear strength). Smooth interface and unbonded-rough interface with shear reinforcement deteriorated under repeated shear loading.

• Steel and Composite Structures
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• v.44 no.6
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• pp.883-898
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• 2022

A hollow-core partially-encased composite beam, named HPEC beam, is investigated in this paper. HPEC beam comprises I-beam, longitudinal reinforcement, stirrup, foam formwork, and cementitious grout. The foam formwork is located on both sides of the web, and cementitious grout is cast within the steel flange. To investigate the shear performance of HPEC beams, static loading tests of six HPEC beams and three control beams were conducted. The shear span ratio and the number of studs on the shear behavior of the HPECspecimens were studied. The failure mechanism was studied by analyzing the curves of shear force versus both deflection and strain. Based on the shear span ratio (𝜆), two typical shear failure modes were observed: shear compression failure when 1.6 ≤ 𝜆 ≤ 2; and diagonal compression failure when 𝜆 ≤ 1.15. Shear studs welded on the flange can significantly increase the shear capacity and integrity of HPEC beams. Flange welded shear studs are suggested. Based on the deformation coordination theory and superposition method, combined with the simplified modified compression field model and the Truss-arch model, Modified Deformation Coordination Truss-arch (M.D.C.T.) model was proposed. Compared with the shear capacity from YB9038-2006 and JGJ138-2016, the calculation results from M.D.C.T. model could provide reasonable predictions.

• Steel and Composite Structures
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• v.15 no.3
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• pp.299-322
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• 2013

In the case of seismic-resistant composite dual moment resisting and eccentrically braced frames, the current design practice is to avoid the disposition of shear connectors in the expected plastic zones, and consequently to consider a symmetric moment or shear plastic hinges, which occur only in the steel beam or link. Even without connectors, the real behaviour of the hinge may be different from the symmetric assumption, since the reinforced concrete slab is connected to the steel element close to the hinge locations, and also due to contact friction between the concrete slab and the steel element. The paper presents the results and conclusions of experimental tests on composite portal eccentrically braced frames and beam-to-column moment-resisting joints, carried out within the CEMSIG Research Centre of the Politehnica University of Timisoara, in order to check the validity of the assumption stated above. Reference steel and composite specimens with and without connectors in the plastic zones have been tested under monotonic and cyclic seismic type loading.

• Steel and Composite Structures
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• v.9 no.2
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• pp.103-118
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• 2009

It has been reported that more than thirty five percent of steel bridges in the USA are structurally deficient because of structural degradations. The degraded structures need either full replacement or rehabilitation such that they are able to provide the required services for a longer period of time. The cost for repair in most cases is far less than the cost of replacement. Moreover, repair method generally takes less time than replacement and also reduces service interruption time. Modern advanced composites have been used in aerospace and automotive fields since World War II. In the recent past, because of the high strength-to-weight ratio and high stiffness-to-weight ratio, these composite materials have been introduced to civil engineering infrastructures primarily for repair and rehabilitation of concrete structures. However, only a few preliminary studies on repair of corroded steel structures using theses composite materials are reported in the literature available in the public domain. Thus, in this study, a series of laboratory tests was undertaken to evaluate the effectiveness of this repair method using carbon fiber reinforced polymer composite. The paper discusses the test method and test results obtained from these tests.

• International Journal of Concrete Structures and Materials
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• v.18 no.3E
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• pp.199-205
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• 2006

The composite frame system with reinforced concrete column and steel beam can be improved in its structural efficiency by complementing the shortcomings of the two systems. The system, however, has many inherent problems in practical design and construction process due to the dissimilarities of the materials. Considering these circumstance, this research aims for the development of a composite structural system which connects the steel beams to the R/C columns with higher structural safety and economy. Basically, the proposed connection system is composed of four split tees, structural angles reinforced by a stiffener, high strength steel rods, connecting plates and shear plates. Structural tests have been carried out to investigate the moment transfer mechanism 1Tom the beam flange to steel rods or connecting plates through the structural angle reinforced by a stiffener. The four prototype specimens have been tested until the flange of the beam reached a plastic state. The test results indicated that no distinct material dissimilarities between concrete and steel have been detected for the proposed hybrid beam-column connection system and that the stress transfer through the structural angle between the beam flange and steel rods or connecting plates was very encouraging.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.76-79
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• 2005

Bending deformation and energy absorption characteristics of aluminum-composite hybrid tube beams have been analyzed for improvement in the bending performance of aluminum space frame by using experimental tests combined with theoretical and finite element analyses. Hybrid tube beams composed of glass fabric/epoxy layer wrapped around on aluminum tube were made in autoclave with the recommended curing cycle. Basic properties of aluminum material used for initial input data of the finite element simulation and theoretical analysis were obtained from the true stress-true strain curve of specimen which had bean extracted from the Al tube beam. A modified theoretical model was developed to predict the resistance to the collapse of hybrid tube beams subjected to a bending load. Theoretical moment-rotation angle curves of hybrid tube beams were in good agreement with experimental ones, which was comparable to the results obtained from finite element simulation. Hybrid tube beams strengthened by composite layer on the whole web and flange showed an excellent bending strength and energy absorption capability.

• Earthquakes and Structures
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• v.12 no.1
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• pp.23-34
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• 2017

Composite steel plate deep beam (CDB) is proposed as a lateral resisting member, which is constructed by steel plate and reinforced concrete (RC) panel, and it is connected with building frame through high-strength bolts. To investigate the seismic performance of the CDB, tests of two 1/3 scaled specimens with different length-to-height ratio were carried out under cyclic loads. The failure modes, load-carrying capacity, hysteretic behavior, ductility and energy dissipation were obtained and analyzed. In addition, the nonlinear finite element (FE) models of the specimens were established and verified by the test results. Besides, parametric analyses were performed to study the effect of length-to-height ratio, height-to-thickness ratio, material type and arrangement of RC panel. The experimental and numerical results showed that: the CDBs lost their load-carrying capacity because of the large out-of plane deformation and yield of the tension field formed on the steel plate. By increasing the length-to-height ratio of steel plate, the load-carrying capacity, elastic stiffness, ductility and energy dissipation capacity of the specimens were significantly enhanced. The ultimate loading capacity increased with increasing the length-to-height ratio of steel plate and yield strength of steel plate; and such capacity increased with decreasing of height-to-thickness ratio of steel plate and gap. Finally, a unified formula is proposed to calculate their ultimate loading capacity, and fitting formula on such indexes are provided for designation of the CDB.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.4 s.56
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• pp.159-169
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• 2009

In this study, static loading tests and numerical analyses of the composite beam strengthened by multi-stepwise thermal prestressing method were carried out to evaluate the prestressing effect of the thermal prestressing prestress and the sectional effect of the installed cover-plate on the increase in the load-carrying capacity of composit beam. From this study, the strengthening method using multi-stepwise thermal prestressing method (TPSM) can be applied to reduce the deflection of the composite beam as well as to strengthening the composite beam by inducing the prestress in case of the occurrence in the large deflection by the insufficiency of the section properties of the composite beam. because of the expectation of the increase in the yield load and the sectional properties of the composite beam.