scholarly journals COMPOSITE REINFORCED CONCRETE BRIDGE GIRDERS FOR POST-CONFLICT RECONSTRUCTION OF THE DESTROYED TRANSPORT INFRASTRUCTURE

2021 ◽  
pp. 28-37
Author(s):  
M. HERNICH ◽  
S. KLUTCHNIK ◽  
D. SPIVAK
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Transport Infrastructure ◽  
Joint Work ◽  
Advantages And Disadvantages ◽  
Post Conflict ◽  
Reinforced Concrete Slabs ◽  
The Impact ◽  
Concrete Girder

Purpose. The purpose of this work is to analyze the existing composite reinforced concrete girder structures of bridges, determine their advantages and disadvantages, study of stress changes in the elements of the girder structure and its deflections caused by the coupling of metal beams and reinforced concrete roadway, the possibility of using these structures in post-conflict reconstruction. Methodology. Examination of the data covered in the literature. Studying the experience of design and construction of reinforced concrete girder structures of bridges in our country and abroad. Construction of the calculation model, its loading, change of thickness of a reinforced concrete plate, the analysis of results. Findings. The result of this work is collected data on the advantages and disadvantages of reinforced concrete girder structures of bridges under the railway, the impact on stress in the elements of the girder structure and on its vertical deflections by the joint work of metal beams and concrete slab, analysis of the possibility of using such girders for fast resumption of train traffic. Originality. It lies in that for the rapid and high-quality restoration of destroyed transport infrastructure, including railways, it is proposed to use metal beams of long-term storage (mobilization reserve), which are made on standard projects in the middle of last century, combined with reinforced concrete slab included in joint work, thereby obtaining composite reinforced concrete girder structures. This will allow rational use of the available reserve of materials, high recovery rates and reliable recovery of train traffic. Practical value. Based on the obtained data, it is possible to conclude that the method of combining the long-term stored metal beams and reinforced concrete slabs of the carriageway increases the load-bearing capacity of the obtained girder structures, so the use of these structures can ensure the effective restoration of war-torn railway structures in a short time.

THE EFFECT OF IMPACT LOADS ON PRESTRESSED CONCRETE SLABS

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Youmn Al Rawi ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Mohamad Elani
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Shear Mode ◽  
Reinforced Concrete Slab ◽  
Finite Element Program ◽  
Reinforced Concrete Slabs ◽  
The Impact

Many research studies have been conducted on the effect of impact loading on structures, and design procedures were proposed for reinforced concrete (RC) slabs; however the availability of these studies and procedures are limited for prestressed slabs. The proposed research will examine, using numerical analysis, the impact of rock fall on prestressed concrete slabs with equivalent moment capacity reinforced concrete slabs. It is expected that prestressed concrete slabs will have different behavior to resist impact loading compared with traditional reinforced concrete slabs. The thickness of the prestressed concrete slab will be 25cm whereas that of the reinforced concrete slab will be 30cm. The impact loading consists of 500Kg drop weight. The drop height will be 10m, 15m and 20m.The structural analysis is performed using a Finite Element program "ABAQUS". A comparison will be done between both slab types in terms of failure mode, damage, and deflection. It has been found that both slabs failed in punching. However, the RC slab performed better than the prestressed concrete slab with respect to the value of the deflection at mid-span, while both showed punching shear mode of failure.

BEHAVIOR OF REINFORCED CONCRETE SLABS UNDER ACCIDENTAL IMPACTS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Shamsoon Fareed
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
High Mass ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Numerical Predictions ◽  
Operational Life ◽  
The Impact

Loads resulting from activities such as rock fall, heavy drop weights (for e.g. equipment's, heavy machines during installation), missile and aircraft interaction with slabs may results in loading intensity which have higher magnitude as compared to static loading. Based on the velocity of the impacting object at the time of contact, these activities may result in impact loading. Therefore, slabs designed should provide resistance to these accidental loading during their entire operational life. In this study, a dynamic non-linear finite element analyses were conducted to investigate the behavior of the reinforced concrete slabs subjected to high-mass low-velocity impacts. For this purpose, initially an already published impact test results were used to validate the numerical predictions. Following validation, a study was conducted to investigate the influence of the impact velocity on the behavior of the reinforced concrete slab. Based on the numerical investigation, it was found that the velocity of the impacting object has a significant influence on the behavior exhibited by slab under impact loading. Furthermore, it was also found that the behavior of slab under impact is both local and global. Local behavior is associated with the damage caused at the contact area of the slab and the impactor, whereas global behavior refers to the overall deformation of the slab when stress waves move away from the impact zone and travel towards the supports.

scholarly journals Long-term study of the impact of temperature changes, material aging and service load on the strains of a reinforced concrete structure

2018 ◽  
Vol 66 ◽  
pp. 02006
Author(s):  
Adam Kanciruk
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Reinforced Concrete Structure ◽  
Reinforced Concrete Slab ◽  
Temperature Changes ◽  
Long Term Study ◽  
Monitoring Process ◽  
Service Load ◽  
The Impact

The article discusses five year long measurements of strains of a concrete floor of a hangar. That hangar, originally meant for servicing light military aircraft, was rebuilt with a view to making it fit for servicing larger and heavier passenger planes. As part of that redevelopment, a new floor - reinforced concrete slab, capable of withstanding the weight of the planes - was constructed. In the areas of the floor where the greatest loads occur, ie. in the areas of the concrete slab on which the wheels of the three undercarriage legs rest, three strain rosettes were installed so that the slab strains could be measured. The rosettes were connected to two meters - dataloggers. The latter were programmed in such a way as to register the measured strains and additionally temperatures many times during every 24 hours. The monitoring process, conducted in such an automatic way, demonstrated the occurrence of strains resulting from service load, aging of the reinforced concrete, as well as changes in its temperature.

scholarly journals MODERN STEEL-CONCRETE SPAN STRUCTURES OF SMALL AND MEDIUM-SPAN BRIDGES

2021 ◽  
pp. 25-34
Author(s):  
Roman Kaplin
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Automatic Welding ◽  
Reinforced Concrete Slab ◽  
Load Bearing ◽  
Metal Elements ◽  
Advantages And Disadvantages ◽  
Concrete Girder

The paper reviews the most common reinforced concrete girder structures of modern bridges used in Ukraine and other countries. The scope, advantages and disadvantages of reinforced concrete structures are considered. The peculiarities of the use of reinforced concrete structures in European countries are reviewed. The most common typical structural solutions of reinforced concrete girder structures used worldwide are given. Options for facilitation of reinforced concrete structures without significant loss of load-bearing capacity are also highlighted. Options for facilitation of structures are presented in the article by lightening the metal load-bearing elements and reducing the weight of the reinforced concrete slab of the carriageway. Reducing the weight of metal elements can be obtained through the use of perforated elements, which can be performed by waste-free technology. To reduce the cost of materials and reduce the weight of the reinforced concrete slab, it is designed lightweight – hollow or ribbed. When removing concrete from the stretched zone, only the ribs of the width required to accommodate the welded frames and ensure the strength of the panels on an inclined cross section are retained. In this case, the plate in the span between the ribs work on the bend as beams of T-section. The top shelf of the plate also works on the local bend between the ribs. During the inspection, the article presents a new design of reinforced concrete girder structure, using perforated box metal elements, made by waste-free technology, and lightweight reinforced concrete slab of the carriageway with hollow formers. Metal blocks are connected to each other by bolts. Metal blocks are made of perforated sheet elements made of waste-free technology. Each block consists of two main beams, transverse diaphragms and a lower plate. The upper belt of the main beams is implemented with the device of horizontal shelves along the entire length of the beams, performing the function of a supporting element for the reinforced concrete slab. Combining all structural elements into a single finished unit is carried out in the factory by automatic welding, which, in turn, allows us to achieve the high factory readiness. The diaphragms of the block are made with a comb along the upper border, on which a profiled steel sheet is placed, which is a fixed formwork for a reinforced concrete slab. The plate is made of non-removable formwork. To ensure the joint operation of the metal part and the reinforced concrete slab, a system of discrete-continuous connections in the form of rigid stops connected in the longitudinal and transverse directions by reinforcing rods is proposed.

scholarly journals Effect of the Geometrical Constraints to the Wenner Four-Point Electrical Resistivity Test of Reinforced Concrete Slabs

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4622
Author(s):  
Kevin Paolo V. Robles ◽  
Jurng-Jae Yee ◽  
Seong-Hoon Kee
Keyword(s):  
Experimental Investigation ◽  
Electrical Resistivity ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Plain Concrete ◽  
Electrode Spacing ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Spacing Ratio ◽  
Geometrical Constraints

The main objectives of this study are to evaluate the effect of geometrical constraints of plain concrete and reinforced concrete slabs on the Wenner four-point concrete electrical resistivity (ER) test through numerical and experimental investigation and to propose measurement recommendations for laboratory and field specimens. First, a series of numerical simulations was performed using a 3D finite element model to investigate the effects of geometrical constraints (the dimension of concrete slabs, the electrode spacing and configuration, and the distance of the electrode to the edges of concrete slabs) on ER measurements of concrete. Next, a reinforced concrete slab specimen (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) was used for experimental investigation and validation of the numerical simulation results. Based on the analytical and experimental results, it is concluded that measured ER values of regularly shaped concrete elements are strongly dependent on the distance-to-spacing ratio of ER probes (i.e., distance of the electrode in ER probes to the edges and/or the bottom of the concrete slabs normalized by the electrode spacing). For the plain concrete, it is inferred that the thickness of the concrete member should be at least three times the electrode spacing. In addition, the distance should be more than twice the electrode spacing to make the edge effect almost negligible. It is observed that the findings from the plain concrete are also valid for the reinforced concrete. However, for the reinforced concrete, the ER values are also affected by the presence of reinforcing steel and saturation of concrete, which could cause disruptions in ER measurements

An Assessment of the Long-Term Durability of Concrete in Radioactive Waste Repositories

1985 ◽  
Vol 50 ◽  
Author(s):  
A. Atkinson ◽  
D. J. Goult ◽  
J. A. Hearne
Keyword(s):  
Reinforced Concrete ◽  
Radioactive Waste ◽  
Concrete Slab ◽  
Laboratory Studies ◽  
Preliminary Assessment ◽  
Reinforced Concrete Slab ◽  
Radioactive Waste Repositories ◽  
Waste Repositories ◽  
Durability Of Concrete

AbstractA preliminary assessment of the long-term durability of concrete in a repository sited in clay is presented. The assessment is based on recorded experience of concrete structures and both field and laboratory studies. It is also supported by results of the examination of a concrete sample which had been buried in clay for 43 years.The enoineering lifetime of a 1 m thick reinforced concrete slab, with one face in contact with clay, and the way in which pH in the repository as a whole is likely to vary with time have both been estimated from available data. The estimates indicate that engineering lifetimes of about 103 years are expected (providing that sulphate resisting cement is used) and that pH is likely to remain above 10.5 for about 106 years.

Experimental Study on Specimens of Steel Secondary Beam Embedded in Reinforced Concrete Girder of Frame Structure

2011 ◽  
Vol 243-249 ◽  
pp. 1072-1084 ◽  
Author(s):  
Qiong Yu ◽  
Zhou Dao Lu ◽  
Jiang Tao Yu ◽  
Xing Zhuang Zhao ◽  
Jin Dai
Keyword(s):  
Reinforced Concrete ◽  
Cantilever Beam ◽  
Concrete Beam ◽  
Concrete Slab ◽  
Frame Structure ◽  
Secondary Beam ◽  
Steel Beam ◽  
Rotational Angle ◽  
Pullout Failure ◽  
Concrete Girder

Test of two specimens (four different joints) of steel secondary beam embedded in reinforced concrete girder in frame structure and one specimen with steel cantilever beam embedded in reinforced concrete girder under static load were conducted. The steel beam up-flange was pulled out because of the concrete cracks caused by the moment, shear and torsion at the upper zone of the concrete beam near the steel beam end. Shear failure of the concrete beam and the top flange pullout failure are the most hazardous failure modes. Lacking restraint of concrete and the reinforcement of steel bar in the concrete slab and catenary action of restraint steel beam, the capacity of steel cantilever beam is much smaller than other beams. Load-slip curve of top flange of steel beam, load-rotation curve of the steel beam end are obtained through experiment. Primary calculation method of joints flexural capacity related to section size of composite steel beam, embedded depth of steel beam, flange width of steel beam embedded end, height of frame girder, is put up with. Analytical results of ABAQUS are shown as follows. Top flange pullout failure of steel beam is caused by the detachment of concrete and steel beam end, and the warp of the concrete slab near the support plays an unfavorable action on the performance of the steel beam. The end rotational angle of the steel beam with anchor bar is smaller than that without. The steel beam with shear connectors develops a smaller rotational angle and a higher load capacity.

scholarly journals Modeling of joint work of steel beam constructions with reinforced concrete ribbed floor slabs

2021 ◽  
pp. 44-57
Author(s):  
Yevhen Dmytrenko
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Precast Concrete ◽  
Concrete Slabs ◽  
Effective Width ◽  
Joint Work ◽  
Load Bearing ◽  
Reinforced Concrete Slabs ◽  
Industrial Buildings ◽  
Floor Slabs

Traditional methods of calculation of beam constructions of floors and coverings of industrial buildings assume their consideration when calculating separately from the frame structures, in particular, reinforced concrete slabs, without taking into account their joint work, which leads to a significant margin of safety. Today in Ukraine there is a significant number of industrial buildings and structures that need strengthening and reconstruction. In this regard, of particular importance are studies of the actual load-bearing capacity of the frames of single-storey and multi-storey industrial buildings, and both in the reconstruction and in new construction, the results of which will significantly reduce costs and more rationally design structures. At the same time, one of the most relevant areas is the study of the joint work of metal load-bearing structures with prefabricated reinforced concrete structures of rigid disks of coatings and floors in their calculation.           Moreover, in the national building codes, as well as in the educational and methodological literature, the calculation methods of taking into account the joint work of such constructions are not fully covered. The purpose of this work is to estimate the reduction of mass of the metal beam structure in its calculation in bending, taking into account the joint work with the rigid disk of the floor consist of precast concrete. As part of the study, the calculation of the floor beam according to the traditional calculation scheme - without taking into account the joint work with the floor slab, the calculation of its cross-section taking into account the joint work with floor slabs and experimental numerical study of the floor by the finite element method. Modeling of the floor fragment was performed in the software packages "SCAD Office" and "LIRA CAD 2019". Numerical research is aimed at verifying the feasibility of using the calculation methodology of DBN B.2.6-98-2009 to determine the effective width of the shelf when calculating the T-sections for prefabricated reinforced concrete slabs, which are included in the joint work with the floor beams. A comparative analysis of the obtained cross-section of the beam with the beam which was previously calculated by the traditional method of calculation  in stresses in the most dangerous cross section and the total mass of the beams. According to the results of the analysis, the correctness of the application of the above normative method for determining the effective width of the shelf of T-bending reinforced concrete elements was confirmed.

The Protection of Turkish Citizens Against Expulsion—This Far and No Further? The Impact of the Ziebell Case

2013 ◽  
Vol 14 (1) ◽  
pp. 239-267
Author(s):  
Kathrin Hamenstädt
Keyword(s):  
Case Law ◽  
Fundamental Rights ◽  
Association Agreement ◽  
Advantages And Disadvantages ◽  
Court Of Justice ◽  
Council Decision ◽  
European Court ◽  
The One ◽  
The Impact

This Article focuses on the Ziebell judgment, in which the European Court of Justice rejected the analogous application of the protection against expulsion for Union citizens to Turkish citizens covered by the Association Agreement. The judgment is placed in the context of the opinion of the Advocate General, the pre-Ziebell judgments of the Court, and judgments of German courts regarding the expulsion of Turkish citizens. On the one hand, against the background of previous case-law of the Court, the judgment might be seen as a setback. On the other hand, the Court's reference to the Long-Term Residents Directive also provides for new interpretative possibilities. Next to the applicability of the directive and the advantages and disadvantages for Turkish nationals triggered by this shift, the interpretative possibilities are discussed in light of fundamental rights and the stand-still obligation anchored in Association Council Decision 1/80.

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