scholarly journals Особенности деформаций главных балок железобетонных пролетных строений автодорожных мостов при их усилении внешней арматурой

2020 ◽  
Vol 44 (3) ◽  
pp. 151-158
Author(s):  
S. Tomilov
Keyword(s):  
Carrying Capacity ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Main Beam ◽  
Relative Deformation ◽  
Operational Parameters ◽  
The Road ◽  
External Reinforcement ◽  
Bridge Structures ◽  
High Degree

Так как в настоящее время в эксплуатации находится достаточно много автодорожных мостов, запроектированных и построенных в различные периоды, их, как и всю дорожную сеть, необходимо поддерживать в состоянии, соответствующем нормативам, а для этого проводить ремонт с использованием элементов усиления несущих конструкций. При качественном возведении и надлежащем уходе высокая степень сохранности мостов позволяет продлить срок их службы путем решения ряда конструктивных вопросов, наиболее актуальным из которых считают обеспечение нормативной грузоподъемности. Усиление с целью повышения грузоподъемности эксплуатируемых мостов достигается путем добавления элементов внешних или внедренных в состав существующего конструктива в зависимости от типа сооружения, его состояния и доступной технологии производства. Однако не только грузоподъемность, но и подверженность конструкций деформациям определяет транспортно-эксплуатационные параметры сооружения, характеризующие послеремонтное состояния моста. Цель настоящего исследования – анализ известного и широко востребованного способа усиления железобетонных балок внешним армированием как обеспечивающего минимальное вмешательство в существующие основные конструкции, технологичного и доступного в исполнении. Впервые дана оценка влияния стадийности включения в работу элементов усиления на общие деформации – прогибы главных балок. Ключевые слова: главная балка, грузоподъемность, усиление, внешняя арматура, свободная затяжка, стадийность работы, относительная деформация, прогиб. Currently, there are quite a lot of road bridges in operation, designed and built in different periods. It is necessary to maintain the road network including bridge structures in a condition that meets up-to-date standards, and for this repair should be carried out using reinforcing elements of the supporting structures. With high-quality construction and proper maintenance, a high degree of safety of bridges allows to extend their service life by solving a number of design issues, the most important of which is considered to be the provision of standard load capacity. Strengthening in order to increase the carrying capacity of operated bridges is achieved by adding elements external or incorporated into the existing structure, depending on the type of structure, its condition and available production technology. However, not only the carrying capacity, but also the susceptibility of structures to deformations determines the transport and operational parameters of the structure, which characterize the post-repair state of the bridge. The purpose of this study is to analyze the well-known and widely demanded method of reinforcing reinforced concrete beams with external reinforcement as providing minimal interference with the existing basic structures, technological and affordable in execution. For the first time, an assessment of the influence of the staging of the inclusion of reinforcement elements in the work on the general deformations – deflections of the main beams. Keywords: main beam, carrying capacity, reinforcement, external reinforcement, free rod, staging of work, relative deformation, deflection.

scholarly journals A critical assessment of domestic and foreign temporary vertical regulatory loads on road bridge structures, a way to eliminate their identified shortcomings

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Pavel Salamahin ◽  
Ilya Reshetnikov
Keyword(s):  
Carrying Capacity ◽  
Road Traffic ◽  
Load Capacity ◽  
Regulatory Documents ◽  
Combined Loads ◽  
Bridge Structures ◽  
The Usa ◽  
The Russian Federation ◽  
Uniformly Distributed Loads ◽  
Economic Considerations

The article critically assessed temporary vertical standard combined loads on road bridges in Western European countries, the USA and Russia. They are set with constant values of the parameters of their uniformly distributed loads and loads on the axles of trucks without regard to the composition of road traffic and out of communication with the length and shape of the lines of influence of force and deformation factors in the elements of bridge structures and are used in these and in many other countries in road bridge structures engineering and design. It is shown that the bridges constructed with different spans on the same road are designed to have different and unknown for designers, engineers and facility managers load capacity, which decreases when the length of the spans increases more than twice, but that is unacceptable for operational and economic reasons. The author found that the use of regulatory documents of other countries as a model for the modernization of domestic standards is unacceptable due to economic considerations. The article assesses the carrying capacity of such bridges as: the Crimean bridge and the Bugrinsky bridge in Novosibirsk. It is shown that these structures, in case of compliance with the requirements of modern regulatory documents of the Russian Federation, do not allow for the passage of columns of vehicles weighing more than 25–27 tons in a state of congestion. The ways of eliminating the identified deficiencies of these combined regulatory loads are indicated. The results of calculations are presented, indicating that a further increase in the parameter K of the AK load to large values is not an effective way of ensuring the required carrying capacity of bridge structures.

scholarly journals WORKS ON BRIDGE REINFORCEMENT ON THE ROAD N2

2019 ◽  
pp. 631-635
Author(s):  
Naser Morina
Keyword(s):  
Carrying Capacity ◽  
Road Traffic ◽  
Load Capacity ◽  
The State ◽  
Design Criteria ◽  
Structural Elements ◽  
The Road ◽  
Current State ◽  
On The Road ◽  
Near Future

The overall objectives of the project are identification and description of repair works and reinforced selected bridges on N2 road to meet the required level of security and services for international heavy road traffic. This is in line with the Eurocodes design criteria. Optimum repair methods and reinforcements are required taking into account the whole set of bridges. If possible, the total amount of repair works and reinforcements will be described as a set of additive works in such a way that parts of works can be selected in the near future. These works should be selected depending on the priority aspects of the load capacity, the safety of repair works and reinforcement are defined from the transition of the current state of the bridges to the requirements established in the Euro codes. The state of the bridge is evaluated with regard to the state of the structural elements in combination with the assessment of the carrying capacity of the bridge.

Experimental Study of Section Enlargement with Reinforced Concrete to Increase Shear Capacity for Damaged Reinforced Concrete Beams

2012 ◽  
Vol 256-259 ◽  
pp. 1148-1153 ◽  
Author(s):  
Yuan Dong Wang ◽  
Shen Yang ◽  
Miao Han ◽  
Xun Yang
Keyword(s):  
Reinforced Concrete ◽  
Epoxy Resin ◽  
Cross Section ◽  
Load Capacity ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Second Phase ◽  
Ultimate Shear Strength ◽  
Ultimate Load Capacity ◽  
External Reinforcement

This paper presents the results of reinforced concrete (RC) beams strengthened in shear by external reinforcement with RC or epoxy resin mortar. The test specimen was 2000mm long with a cross section of 150mm×200mm and after section enlargement the cross section was increased to 250mm×300mm, in addition, shear span to beam depth ratio of a/h0 was 2.35. All specimens had the same geometry and were distinguished by the configurations of stirrup which was the primary test variable. No shear reinforcement was provided in the first phase of test, while in the second phase external RC or epoxy resin mortar was provided to enable failure due to shear. Experiments are undertaken to investigate the influence of preexisting damage, configurations of stirrup and different methods on the strengthened behavior and mode of failure. A group unstrengthened control beams were tested and failed in shear. In contrast to the control beam, all of the strengthened beams showed a significant improvement in their ultimate load capacity when they were failing in shear. The enlarged section with reinforced concrete can significantly increase the ductility and ultimate shear strength of a concrete beam. The method of section enlargement with RC is a high effective technique to enhance shear ability. An analysis for shear strengthening of beams using external reinforcement with RC has also been carried out as well.

scholarly journals Design of Optimal Rainfall Monitoring Network Using Radar and Road Networks

Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 378
Author(s):  
Taeyong Kwon ◽  
Seongsim Yoon ◽  
Sanghoo Yoon
Keyword(s):  
Road Networks ◽  
Monitoring Network ◽  
Conditional Entropy ◽  
Radar Data ◽  
Disaster Risk ◽  
Water Levels ◽  
The Road ◽  
Dam Operation ◽  
A Site ◽  
High Degree

Uncertainty in the rainfall network can lead to mistakes in dam operation. Sudden increases in dam water levels due to rainfall uncertainty are a high disaster risk. In order to prevent these losses, it is necessary to configure an appropriate rainfall network that can effectively reflect the characteristics of the watershed. In this study, conditional entropy was used to calculate the uncertainty of the watershed using rainfall and radar data observed from 2018 to 2019 in the Goesan Dam and Hwacheon Dam watersheds. The results identified radar data suitable for the characteristics of the watershed and proposed a site for an additional rainfall gauge. It is also necessary to select the location of the additional rainfall gauged by limiting the points where smooth movement and installation, for example crossing national borders, are difficult. The proposed site emphasized accessibility and usability by leveraging road information and selecting a radar grid near the road. As a practice result, the uncertainty of precipitation in the Goesan and Hwacheon Dam watersheds could be decreased by 70.0% and 67.9%, respectively, when four and three additional gauge sites were installed without any restriction. When these were installed near to the road, with five and four additional gauge sites, the uncertainty in the Goesan Dam and Hwacheon Dam watersheds were reduced by up to 71.1%. Therefore, due to the high degree of uncertainty, it is necessary to measure precipitation. The operation of the rainfall gauge can provide a smooth site and configure an appropriate monitoring network.

scholarly journals Finite element analysis of reinforced concrete deep beam with large opening

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Elsayed Ismail ◽  
Mohamed S. Issa ◽  
Khaled Elbadry
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
The Other ◽  
Deep Beam ◽  
Web Openings ◽  
Design Load ◽  
Large Opening

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.

The Application Research of Reinforced Concrete Multi-Ribbed Hollow Composite Slab in the Road Slab Culvert

2011 ◽  
Vol 368-373 ◽  
pp. 307-311
Author(s):  
Dong Qi Zhao ◽  
Yi Jun Tang ◽  
Hui Li ◽  
Gui Feng Song ◽  
Feng Ling Guan
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Concrete Cover ◽  
Reinforced Concrete Beams ◽  
Application Research ◽  
Composite Slab ◽  
The Road ◽  
High Integrity ◽  
Cover Design ◽  
Bottom Slab

Reinforced concrete cover in the road culvert cover design, in order to facilitate the construction, usually using precast reinforced concrete solid slab, but the overall cost is not low. This article researched a reinforced concrete multi-ribbed hollow composite slab, it based on the theory of reinforced concrete multi-ribbed slab structures, using a precast reinforced concrete ribbed slab as the bottom die, then poured reinforced concrete beams and panels rib ,and them constituted a whole stack of reinforced concrete ribbed hollow slab. This kind of cover, compared with the precast reinforced concrete solid cover, is not only good mechanical properties, high integrity, but also saving concrete, steel, and bottom slab appeared smooth and fine, lower construction cost.

About Determing the Microhardness of Composite Coatings

2021 ◽  
Vol 1037 ◽  
pp. 486-493
Author(s):  
Sergey Y. Zhachkin ◽  
Anatoly I. Zavrazhnov ◽  
Nikita A. Penkov ◽  
George V. Kudryavtsev ◽  
Paul V. Tsisarenko
Keyword(s):  
Composite Coating ◽  
Mechanical Treatment ◽  
Composite Coatings ◽  
Operational Parameters ◽  
Deposition Parameters ◽  
Cylinder Liners ◽  
High Degree ◽  
Applied Coating ◽  
Positive Effect ◽  
Selection Of

One of the fundamental tasks in restoring the operability of cylinder liners is the application of a composite coating with a predetermined microhardness value. The authors have developed a technology for applying composite coatings based on iron on cylindrical surfaces, which makes it possible to vary the physical, mechanical and operational parameters of the formed iron-containing coating due to the planned selection of the deposition parameters. This eliminates the need for mechanical treatment of the applied coating, which is the reason for the high degree of rejection parts that undergo the iron-on operation. Contact interaction of the working tool with the formed layer of the composite coating has a positive effect on the value of its roughness.

Study of the Influence of the Beam-Column Line Stiffness Ratio on the Frame Structure Load Capacity Based on MATLAB

2011 ◽  
Vol 71-78 ◽  
pp. 4194-4198
Author(s):  
Shao Qin Zhang ◽  
Hua Hu Cheng
Keyword(s):  
Engineering Design ◽  
Carrying Capacity ◽  
Calculated Result ◽  
Load Capacity ◽  
Frame Structure ◽  
Stiffness Ratio ◽  
Displacement Method ◽  
Structure Form ◽  
The Matrix ◽  
Internal Forces

Statically indeterminate frame, composed of beams and columns, is a widely used structure form in civil engineering. The frame carrying capacity under various actions is related to the absolute stiffness of frame components and relative beam-column line stiffness ratio. The matrix displacement method and programming based on MATLAB were employed in this study to calculate the internal forces and displacements of a 2-bay 2-story frame structure under the action of horizontal loads. The influence of the beam-column line stiffness ratio on the frame load capacity was discussed based on the calculated result. Furthermore some advises were provided about the reasonable beam-column line stiffness ratio for engineering design.

scholarly journals RETROFITTING AND DACTILITY OF REINFORCED CONCRETE BEAMS USING AN EXTERNAL REINFORCEMENT METHOD

2019 ◽  
Vol 3 (2) ◽  
pp. 135
Author(s):  
Novita Ike Triyuliani ◽  
Sri Murni Dewi ◽  
Lilya Susanti
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Concrete Block ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Building Structures ◽  
Average Increase ◽  
External Reinforcement ◽  
Strength And Ductility

The innovations strengthening building structures are important topics. Failure in structures such as beams and columns due to time, re-functions of a building, even initial design errors that are weak or lack the safety factor of a building structure. External reinforced concrete beams are one of the beams currently being developed. It is a concrete block with reinforcement of steel reinforcement on the outer (external) of the beam. This study aims to determine the index of increasing beam strength and ductility after retrofitting external steel reinforcement, which has the dimension of beams 15 x 15 x 100 cm, repeating 12 pcs, with external reinforcement each 6 pcs 2Ø6 and 3Ø6. The results from this study are an increasing the index of beam flexural strength after retrofit with external steel reinforcement. Meanwhile, beams after retrofit with 2Ø6 external steel have an average increase index of 1.25 and 1.21 while for external steel 3Ø6 are 1.29 and 1.60 respectively. The ductility depends on the value of ultimate load and maximum deflection that occurs, where the ductility value for the comparison of each specimen experiences a reduction in the average ductility value with 2Ø6 external steel which is 37.74% and 70.95% while with 3Ø6 external steel is 61,65% and 60.62%. Berbagai inovasi upaya peningkatan kekuatan struktur bangunan telah menjadi bahasan yang penting. Kegagalan pada struktur seperti balok dan kolom karena umur, alih fungsi suatu bangunan, bahkan kesalahan desain awal yang lemah atau kurang memenuhi faktor keamanan suatu struktur bangunan. Balok beton bertulangan eksternal adalah salah satu balok yang sedang dikembangkan pada saat ini, yaitu balok beton dengan perkuatan tulangan baja di sisi terluar (eksternal). Penelitian ini bertujuan untuk mengetahui indeks peningkatan kekuatan balok dan daktilitas setelah dilakukan perbaikan menggunakan tulangan baja eksternal, dengan dimensi balok 15 × 15 × 100 cm berulang 12 buah, penambahan tulangan baja eksternal masingmasing 6 buah 2Ø6 dan 3Ø6. Hasil yang didapat dari penelitian ini adalah indeks peningkatan kekuatan lentur balok setelah dilakukan perbaikan menggunakan tulangan baja eksternal. Dimana balok setelah dilakukan perbaikan dengan baja eksternal 2Ø6 memiliki indeks peningkatan rata-rata 1,25 dan 1,21 sedangkan untuk baja eksternal 3Ø6 masing-masing 1,29 dan 1,60. Daktilitas tergantung dari nilai beban ultimit dan lendutan maksimum yang terjadi, dimana nilai daktilitas untuk perbandingan tiap benda uji mengalami reduksi nilai daktilitas rata-rata dengan baja eksternal 2Ø6 yaitu sebesar 37,74% dan 70,95% sedangkan dengan baja eksternal 3Ø6 sebesar 61,65% dan 60,62%.

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