scholarly journals MODELING THE WORK OF THE STRUCTURE STRENGTHENING STRUCTURE STRUCTURE BY THE METHOD OF CONNECTING A FOUNDATION BOARD WITH A REMOVABLE FORMWORK IN A TRAY

2020 ◽  
Vol 8 (1) ◽  
pp. 39-47
Author(s):  
Vitaliy Subbotin

The conditions of creating a model for conducting experimental studies in a tray of a patented reinforcement design of existing strip foundations are considered. It is proposed to simulate and investigate the effectiveness of the new design of reinforcement of the strip foundation, allowing to take into account the rheological processes in the soil of the base when performing measures for structural reinforcement using a profiled sheet in conjunction with monolithic elements. Based on the rules of modeling and similarity theory, it is proposed to determine the optimal conditions for experimental modeling of a solution to strengthen existing monolithic reinforced concrete strip foundations by working together with a monolithic reinforced concrete slab divided by a profiled sheet in height into two parts (upper and lower) with injection wells for injection of a hardening mortar directly under fixed formwork from a profiled sheet

2014 ◽  
Vol 13 (2) ◽  
pp. 265-274
Author(s):  
Marek Łagoda ◽  
Krzysztof Śledziewski

The theme of the paper is the effect of scratching of reinforced concrete slab on the work of a steel-concrete composite beam. The paper evaluates the state of knowledge in the field of composite structures, in particular, statically indeterminate structures with concrete in tension zones. Additionally, in a nutshell, it describes the current practice of design. Moreover, experimental studies were described on continuous beams that were made by the authors. A proposal for further work on this topic was also presented.


The analysis of various regulatory methods for calculating reinforced concrete slabs for punching and comparing with experiment results is made. The tested sample, measuring equipment and test bench are described. Dimensions and materials for the production of the prototype were chosen on the basis of experience in the construction of girderless and capless regular monolithic reinforced concrete frames. The results of experimental studies of a fragment of a slab reinforced concrete structure in order to study the stress-strain state, when implementing the mechanism of punching, are presented. The results of observations obtained during the tests are presented. A comparison of the nature of operation of the tested fragment of the slab with the nature of operation of the full-fledged construction is given. A comparative analysis of the stress-strain state of the tested sample and the results of the calculation of the bearing capacity for punching according to various normative methods is performed. According to the results of the experiment, the main criteria determining the implementation of the punching mechanism are established, and a new method for calculating girderless floors is proposed on the basis of a fundamentally different approach in determining the bearing capacity.


2019 ◽  
Vol 968 ◽  
pp. 361-367 ◽  
Author(s):  
Andrii Kovalov ◽  
Yuriy Otrosh ◽  
Mykola Surianinov ◽  
Tatiana Kovalevska

The unsatisfactory technical condition of many buildings and structures is due to their aging and requires a quick technical condition assessment. The most promising way for experimental researches data verification is computer modeling of structures, also during a fire. It is advisable to use the ANSYS software. Experimental fire tests of reinforced concrete slabs were carried out. In order to assess the experiment quality and the reliability of the received temperature distribution data, it was used a reinforced concrete slab computer simulation in the ANSYS R.17.1 software system. There was provided a comparative analysis of experimental studies results and numerical data analysis. The results confirm that method of conducted experimental research and computer simulation with further numerical analysis can be recommended for practical application. The mathematical model makes possible operative prediction for the controlled parameters values of building structures.


2021 ◽  
Vol 3 (2) ◽  
pp. 64-74
Author(s):  
I. Korneieva ◽  
◽  
D. Kirichenko ◽  
O. Shyliaiev ◽  
◽  
...  

The results of experimental studies of deformability and crack resistance of models of aerodrome slabs made of reinforced concrete and steel-fiber concrete, made on the basis of serial slab PAG-18 taking into account the scale factor, are presented. Two series of slabs were tested - two models of reinforced concrete and two models with one-percent dispersed reinforcement. The load was applied in steps, the instrument readings were recorded twice at each step and the crack opening width was measured starting from the moment of the first crack formation. Dial gauges, deflectometer and microscope MPB-3 were used as measuring instruments. In accordance with the normative documents acting in Ukraine, one of two possible loading schemes was considered - with the loading by the concentrated force applied in the span part of a plate which had a hinged support along its short sides. Plate models were tested on a specially made stand. Each load step ended with a five-minute dwell time, at the beginning and the end of which readings were taken on the measuring instruments. The deformations at the same levels were measured with dial gauges. The process of crack formation was observed with a Brinell tube in the places of the greatest crack opening. Breaking load for fiber concrete slab was 1.52 times higher than for reinforced concrete slab, and the moment of cracking initiation was 1.22 times higher. The process of cracking in the fiber concrete slab begins at higher loads than in the reinforced concrete slab. The initial crack opening width of the slabs is almost the same, and the final crack opening width of all the cracks in the fiber concrete slab is significantly lower than in the reinforced concrete slab. The deformations in steel-fiber concrete slabs when the load is applied in the span, both for compressed and stretched fibers, are higher than in reinforced concrete slabs. The experimental studies indicate that dispersed reinforcement of airfield slabs with steel fiber leads to their higher crack resistance.


2020 ◽  
Vol 310 ◽  
pp. 00051
Author(s):  
Barbara Wieczorek

The paper presents the problem of protection of reinforced concrete slab-column structures against the occurrence of a progressive collapse caused by punching in the support zone. The experimental studies and effects of recorded collapses indicate the necessity to use the appropriate reinforcement type, which will significantly increase the load capacity of the slab-column connection after punching. One of the ways to protect the structure is to use an integrity reinforcement as the most optimal method of strengthening. The contents explain the reasons for the application and description of issues related to this type of reinforcement. The conclusions from the use of this reinforcement based on the results of laboratory tests were presented.


Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7113
Author(s):  
Kevin Paolo V. Robles ◽  
Dong-Won Kim ◽  
Jurng-Jae Yee ◽  
Jin-Wook Lee ◽  
Seong-Hoon Kee

The main objectives of this research are to evaluate the effects of delamination defects on the measurement of electrical resistivity of reinforced concrete slabs through analytical and experimental studies in the laboratory, and to propose a practical guide for electrical resistivity measurements on concrete with delamination defects. First, a 3D finite element model was developed to simulate the variation of electric potential field in concrete over delamination defects with various depths and lateral sizes. Second, for experimental studies, two reinforced concrete slab specimens (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) with artificial delamination defects of various dimensions and depths were fabricated. Third, the electrical resistivity of concrete over delamination defects in the numerical simulation models and the two concrete slab specimens were evaluated by using a 4-point Wenner probe in accordance with AASHTO (American Association of State Highway and Transportation Office) T-358. It was demonstrated from analytical and experimental studies in this study that shallow (50 mm depth) and deep (250 mm depth) delamination defects resulted in higher and lower electrical resistivity (ER) values, respectively, as compared to measurements performed on solid concrete locations. Furthermore, the increase in size of shallow defects resulted in an increase in concrete resistivity, whereas the increase in sizes of deep delamination defects yielded opposite results. In addition, measurements done directly above the steel reinforcements significantly lowered ER values. Lastly, it was observed from experimental studies that the effect of delamination defects on the values of electrical resistivity decreases as the saturation level of concrete increases.


A combination of outstanding advantages of concrete filled steel tube (CFST) column with reinforced concrete (RC) flat slab creates the effective and potential structure to replace traditional reinforced concrete frame structures in high-rise buildings. The CFST column – RC slab connection is the key factor for this structure type to work properly and effectively. Currently, the studies mainly focus on inner CFST column and RC slab connection, there are very few experimental studies on connection of edge or corner CFST columns and RC flat slab. This paper proposes edge and corner CFST columns to RC flat slab connection structures using H-shaped shear head and then conducts two large size tests to investigate behaviors of the connection.


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