scholarly journals Analysis of steel-reinforced high-strength concrete deep beam displacement under dynamic loads

2018 ◽  
Vol 67 (3) ◽  
pp. 165-183
Author(s):  
Waldemar Cichorski

The paper presents an analysis of the deformation of a dynamically loaded rectangular reinforced-concrete deep beam, including the physical nonlinearity of construction materials: concrete and reinforcing steel. The solution was acquired with the use of the method presented in [15]. The displacement of three plate types under various loads, up to dynamic load capacity depletion, was analysed. The results of numerical solutions are presented, with particular emphasis on the impact of the very high strength of concrete and steel on the reinforced concrete plate displacement. The work confirmed the correctness of the assumptions and deformation models of concrete and steel as well as the effectiveness of the methods of analysis proposed in the paper [1, 15] for the problems of numerical simulation of the behaviour of reinforced concrete deep beams under dynamic loads. Keywords: mechanics of structures, reinforced concrete structures, deep beams, dynamic load, physical nonlinearity.

2018 ◽  
Vol 67 (4) ◽  
pp. 15-40
Author(s):  
Waldemar Cichorski

The paper presents an analysis of the dynamic load capacity of a dynamically loaded rectangular reinforced-concrete deep beam made of high-strength materials, including the physical nonlinearity of the construction materials: concrete and reinforcing steel. The solution was acquired with the use of the method presented in [15]. The dynamic load capacity of the reinforced concrete beam was determined. The results of numerical solutions are presented, with particular emphasis on the impact of the very high strength of concrete and steel on the reinforced concrete beam’s dynamic load capacity. The work confirmed the correctness of the assumptions and deformation models of concrete and steel as well as the effectiveness of the methods of analysis proposed in the paper [1, 15] for the problems of numerical simulation of the behaviour of reinforced concrete deep beams under dynamic loads. Keywords: mechanics of structures, reinforced concrete structures, deep beams, dynamic load, physical nonlinearity.


2018 ◽  
Vol 67 (3) ◽  
pp. 129-154
Author(s):  
Waldemar Cichorski

This work demonstrates an analysis of the displacement state of rectangular concrete deep beams made of very high strength concrete grade C300 under a dynamic load, including the physical nonlinearity of construction materials: concrete and reinforcing steel. The analysis was conducted with the method presented in [1]. Numerical solution results are presented with particular reference to the displacement state of a rectangular concrete deep beam. The work confirmed the accuracy of the assumptions and deformation models of concrete and steel as well as the effectiveness of the methods of analysis proposed in the paper [1] for the problems of numerical simulation of the behaviour of reinforced concrete deep beams under dynamic loads. A comparative analysis was conducted on the effect of the high-strength concrete and the steel of increased strength on the displacement of a grade C300 concrete deep beam vs. the results produced in [10] for grade C100 and C200 concrete deep beams. Keywords: mechanics of structures, reinforced concrete structures, deep beams, dynamic load, physical nonlinearity.


2018 ◽  
Vol 67 (2) ◽  
pp. 25-48
Author(s):  
Waldemar Cichorski

The dynamic load displacements were analysed of rectangular concrete deep beams made of very high strength concrete, grade C200, including an evaluation of the physical non-linearity of the construction materials: concrete and reinforcing steel. The analysis was conducted using the method presented in [1]. The numerical calculation results are presented with particular reference to the displacement state of rectangular concrete deep beams. A comparative analysis was conducted on the effect of the high-strength concrete and the steel of increased strength on a class C200 concrete deep beam versus the results produced in [10] for a class C100 concrete deep beam. Keywords: mechanics of structures, reinforced concrete structures, deep beams, dynamic load, physical non-linearity


2018 ◽  
Vol 67 (1) ◽  
pp. 141-174
Author(s):  
Waldemar Cichorski

The work presented is a three-part set of studies containing a comparative analysis of the displacement state of rectangular concrete deep beams made of concrete of different classes of very high strength, loaded dynamically. The analysis was carried out on the basis of the method presented in this paper [1], which allows for the physical nonlinearity of structural materials: concrete and reinforcing steel to be taken into account. Each part of the work contains the results of numerical solutions of the displacement state of the deep beams separately for the concrete strength of C100 grade, C200 grade, and C300 grade, in each case reinforced with ordinary steel and increased strength steel. Comparative analysis is carried out in Part Two and Part Three, where the results obtained in these parts are respectively compared with the results obtained in the preceding parts. The analysis includes the mutual relations of mechanisms for achieving dynamic load carrying — capacity. The results describing the variation of displacements in time indicate the characteristic features of the deep beam effort and allow for the inference on reaching the state of the dynamic load carrying — capacity. In general, the work confirmed the accuracy of the assumptions and deformation models of concrete and steel as well as the effectiveness of methods of analysis proposed in paper [1] for the problems of numerical simulation of reinforced concrete deep beams behaviour under dynamic loading. The key assumptions used in the analysis are presented in the first part of the paper. The characteristic features of structural materials: concrete and reinforcing steel are presented, taking into account the modified idea of modelling of the dynamic properties of concrete as a material of very high strength. An analysis of the displacement state of rectangular reinforced concrete deep beams made of very high strength concrete of C100 grade under dynamic load for two types of reinforcing steel — ordinary and increased strength — was carried out. Key words: mechanics of structures, reinforced concrete structures, deep beams, dynamic load, physical nonlinearity


Author(s):  
Valery Stanislavovich Lesovik ◽  
Aleksandr Dmitrievich Tolstoy ◽  
Ruslan Valeryevich Lesovik ◽  
Aleksandr Anatolevich Volodchenko ◽  
Hans-Bertram Fisher

Nowadays, with the advancement of science and technology, a big step has been taken in strengthening and improving concrete structures. Structure reinforcement with composite materials is one of the methods that has been considered and used in civil industry in recent years. One of the application domains of composite materials is to improve and increase the load capacity. This paper investigates the composite structure performance under the dynamic loads. Findings showed that these structures are low risk in the high and dynamic loads, which improves the structure life time. Increased corrosion resistance of the structure is a significant improvement in these materials. The load-bearing capacity of composite surfaces is 7 times that of reinforced concrete surfaces, while their weight is very light.


2020 ◽  
Vol 14 (1) ◽  
pp. 51-69
Author(s):  
Hayder H. H. Kamonna ◽  
Qasim M. Shakir ◽  
Haider A. Al-Tameemi

Background: When a beam is loaded on two opposite faces and the beam’s depth is increased such that either the span-to-depth ratio is smaller than four or the shear-span-to-depth ratio is less than two, it will behave like a deep beam. Strain distribution in deep beams is different from that of ordinary beams because it is nonlinear along with the beam depth. If the beam is cast monolithically with a slab in the slab–beam system, it is considered a T-deep beam. The behavior of the resulting member is more complicated. Objective: The effect of flange width on the behavior of high-strength self-consolidated reinforced concrete T-deep beams was investigated. Methods: Experimental and numerical studies were conducted. Two shear span-to-depth ratios (1.25 and 0.85) were adopted for two groups. Each group consisted of four specimens: one rectangular beam that served as a reference beam and three flanged beams with flange widths of 440, 660 and 880 mm. All specimens had an overall depth of 450 mm, a width of 160 mm and a total length of 1600 mm. The tests were performed under a two-point load with a clear span of 1400 mm. A nonlinear analysis was also performed using ANSYS software. Results: Throughout the study, the performance of the T-deep beams has been investigated in terms of cracking loads, failure loads, modes of failure, loading history, rate of widening of cracks and ductility index. Results revealed that such parameters have a different ranges of effect on the response of T-deep beams. Calibration of the ANSYS model has been done by comparing results of load-deflection curves, cracking and failure loads with that obtained experimentally. Conclusion: The study’s results indicated that increasing the flange width yielded an 88% improvement in the failure load and an approximately 68% improvement in the cracking load. This positive effect of flange width on the failure load was more pronounced in beams with higher shear span to- depth ratios and flange widths of 660 mm. In addition, the beam’s ductility was improved, especially in cases corresponding to a higher shear span-to-depth ratio. The finite element simulation showed good validation in terms of the load-deflection curve with a maximum failure load difference of 9%. In addition, the influence of longitudinal steel reinforcement on the behavior of such members was studied. Some parameters that reflect the effect of changing the flange width on the behavior of deep beams were also presented. Increasing the flange width is more effective when using normal strength concrete than when using high-strength concrete in terms of cracking load, beam stiffness, and failure load.


Author(s):  
Elsayed Ismail ◽  
Mohamed S. Issa ◽  
Khaled Elbadry

Abstract Background A series of nonlinear finite element (FE) analyses was performed to evaluate the different design approaches available in the literature for design of reinforced concrete deep beam with large opening. Three finite element models were developed and analyzed using the computer software ATENA. The three FE models of the deep beams were made for details based on three different design approaches: (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978), (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006), and Strut and Tie method (STM) as per ACI 318-14 (ACI318 Committee, Building Code Requirements for Structural Concrete (ACI318-14), 2014). Results from the FE analyses were compared with the three approaches to evaluate the effect of different reinforcement details on the structural behavior of transfer deep beam with large opening. Results The service load deflection is the same for the three models. The stiffnesses of the designs of (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) and STM reduce at a load higher than the ultimate design load while the (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) reduces stiffness at a load close to the ultimate design load. The deep beam designed according to (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) model starts cracking at load higher than the beam designed according to (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) method. The deep beam detailed according to (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) and (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) failed due to extensive shear cracks. The specimen detailed according to STM restores its capacity after initial failure. The three models satisfy the deflection limit. Conclusion It is found that the three design approaches give sufficient ultimate load capacity. The amount of reinforcement given by both (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) and (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) is the same. The reinforcement used by the STM method is higher than the other two methods. Additional reinforcement is needed to limit the crack widths. (Mansur, M. A., Design of reinforced concrete beams with web openings, (2006)) method gives lesser steel reinforcement requirement and higher failure load compared to the other two methods.


Author(s):  
A.A. Komarov ◽  

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.


2021 ◽  
Vol 28 (1) ◽  
pp. 71-83
Author(s):  
Mazin Abdulrahman ◽  
Shakir Salih ◽  
Rusul Abduljabbar

In this research, an experimental study is conducted to investigate the behavior and strength of high strength reinforced concrete corbels externally bonded with CFRP fabric sheets and Plates with different patterns taking into account the effect of adopted variables in enhancing the ultimate strength; the effect of shear span to effective depth (a/d), configuration, type and amount of bonding. Eleven high strength reinforced corbels were cast and tested under vertical loads. Test results showed there was an improvement in the behavior and load carrying capacity of all strengthened corbels. An increasing in the ultimate strength of strengthened corbel by inclined CFRP strips reached to (92.1%) while the increasing reached to (84.21%) for using one horizontal CFRP Plates compared to un-strengthened reference specimen. Also, it can be conducted that the increase of (a/d) ratio from (0.6 to 0.8) resulted in decreasing by 21.05% in ultimate load capacity of corbels and from (0.4 to 0.6) by 31.25% and 58.69% in cracking and ultimate loads respectively Using CFRP .


2011 ◽  
Vol 243-249 ◽  
pp. 514-520
Author(s):  
Chun Yang ◽  
Ming Ji He ◽  
Jian Cai ◽  
Yan Sheng Huang ◽  
Yi Wu

Based on strut-and-tie model (STM) in deep beams, steel truss reinforced concrete (STRC) deep beam was developed. Experimental investigations of mechanical performances of STRC deep beams were carried out, and results show that STRC deep beam is of high ultimate bearing capacity, large rigidity and good ductility; Strut-and-tie force transference model is formed in STRC deep beams, and loads can be transferred in the shortest and direct way. Then Steel reinforced concrete (SRC) strut-and-tie model (SSTM) for determining the shear strength of STRC deep beams is proposed. The contribution of SRC diagonal strut, longitudinal reinforcements, stirrups and web reinforcements to the shear strength of STRC deep beams are determined with consideration of softened effects of concrete, and for safe consideration, superposition theory is employed for SRC struts. Computer programs are developed to calculate the shear strength of STRC deep beams and verified by experimental results.


Sign in / Sign up

Export Citation Format

Share Document