scholarly journals Strengthening and Repair of a Precast Reinforced Concrete Residential Building

2020 ◽  
Vol 6 (12) ◽  
pp. 2457-2473
Author(s):  
M. Jamal Shannag ◽  
Mahmoud Higazey
Keyword(s):  
Reinforced Concrete ◽  
Residential Building ◽  
Minimum Cost ◽  
High Strength ◽  
Cost Effective ◽  
Steel Beams ◽  
Reinforced Concrete Structure ◽  
Design Error ◽  
Analytical Tools ◽  
Repair Techniques

The deterioration or ageing of the existing infrastructures coupled with increased safety requirements necessitate immediate strengthening. Developing long lasting and cost effective repair techniques and materials continue to capture the attention of concrete professionals worldwide. The main purpose of this investigation was to extend the life span of a multi-storey precast reinforced concrete structure built in Riyadh 40 years ago. The condition assessments relied on analytical tools, visual, field and laboratory experiments for core samples collected from the building. The analytical checks of the building revealed considerable deflections of some slabs because of design error. The field and chemical analysis tests performed, confirmed the occurrence of durability defects as a result of poor workmanship during the construction stage. Several state-of-the-art repair techniques and materials were used for enhancing the service life of the structure at a minimum cost. The Repair strategy implemented included, removal of the deteriorated concrete, pouring a bonding agent on the surface of the damage, followed by injecting high strength cementitious grouts, supporting the deflected slabs using I-section steel beams, using cathodic protection to prevent corrosion, strengthening the columns and beams using carbon fiber reinforced polymer (CFRP) sheets, and steel jackets. Doi: 10.28991/cej-2020-03091630 Full Text: PDF

Steel-Reinforced Concrete Floors With The Use Of Bent Steel Profiles

2020 ◽  
pp. 10-14
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Theoretical Research ◽  
Steel Beams ◽  
Reinforced Concrete Structure ◽  
Reinforced Concrete Slab ◽  
Steel Reinforced Concrete ◽  
Advantages And Disadvantages ◽  
Concrete Strengthening

The issues of designing a steel-reinforced concrete floor using bent steel profiles are considered. The steel-reinforced concrete flooring consists of a monolithic reinforced concrete slab arranged on a removable formwork, and steel bent profiles. The removable formwork during the concreting process rests on steel beams without additional mounting posts in the floor span. Steel beams accept the weight of the formwork and concrete during the pouring, working on bending. After concrete strengthening, they mainly work on stretching as part of composite steel-reinforced concrete structure. The article has identified the advantages and disadvantages of steel-reinforced concrete flooring with the use of light steel thin-walled bent profiles. Checking the strength of the beam at the concreting stage and evaluating the load-bearing capacity of the floor after the concrete strength is set confirm the performance of this structure. Using the regulatory methodology for SP 266.1325800.2016, the area of implementation of steel and concrete flooring with CFS beams and the nomenclature of applied steel beams have been established. For practical application of the presented design, it is recommended to conduct experimental and theoretical research and develop engineering methods.

UHPFRC as Repair Material for Fire-Damaged Reinforced Concrete Structure – A Review

2015 ◽  
Vol 802 ◽  
pp. 283-289 ◽  
Author(s):  
Muhd Afiq Hizami Abdullah ◽  
Mohd Zulham Affandi Mohd Zahid ◽  
Badorul Hisham Abu Bakar ◽  
Fadzli Mohamed Nazri ◽  
Afizah Ayob
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
High Performance ◽  
Steel Fibre ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Repair Material ◽  
Reinforced Concrete Structure ◽  
Normal Concrete ◽  
High Performance Fiber

Exposure of concrete to intense heat will cause deterioration of its strength and durability. Previously, the fire-damaged concrete was repaired using the shotcrete and normal concrete. Recent studies utilize fibre reinforced polymer (FRP) in repairing fire-damaged concrete. Ultra High Performance Fiber Reinforced Concrete (UHPFRC) mostly developed using fine size aggregate, cement, silica fume, super plasticizer and reinforced with steel fibre has an excellent mechanical properties compared to high strength concrete and with an addition of steel fibre in the UHPFRC enhances its ductility behaviour which is not possessed by normal concrete, hence, UHPFRC indicates a promising candidate as repair material to fire-damaged concrete. The aim of this paper is to review on the properties of UHPFRC to be utilized as repair material to fire-damaged concrete structure based on previous research on UHPFRC and fire-damaged structure.

scholarly journals Analysis of constructive parameters of vertical reinforced concrete structure with self-compacting concrete

2020 ◽  
Vol 13 (5) ◽  
Author(s):  
Jordana Herbster Ferraz Serra ◽  
Antonio Eduardo Bezerra Cabral
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Residential Building ◽  
Accident Risk ◽  
Use Of Self ◽  
Reinforced Concrete Structure ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Self Compacting Concrete ◽  
Work Related

abstract: The objective of this paper is to quantify the improvements due to the use of self-compacting concrete (SCC) as a replacement to a conventional Portland Cement Concrete (PCC) in the production of a reinforced concrete structure of a typical residential building in Brazil. To achieve the proposed objectives, a SCC mix was developed in the laboratory and tests were performed in the fresh and hardened states. Two floors, consisting of columns, beams and slabs, were built with SCC and a third with PCC. Pouring time and its generated noise, appearance of pathological manifestations after pouring, amount of labor required for pouring, costs and the risk of work-related accidents were evaluated. The results indicate that the floors produced with the SCC obtained 60.5% less pouring time, a reduction of 50% and 62.8% in the quantity and costs of labor, respectively; 260.8% reduction in the accident risk factor and, finally, a reduction of 56.4% in the total cost.

scholarly journals An approach to increasing the load-bearing capacity of drilled injection piles

2021 ◽  
Vol 274 ◽  
pp. 03016
Author(s):  
Nikolay Sokolov
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Residential Building ◽  
Longitudinal Axis ◽  
Reinforced Concrete Structure ◽  
Load Bearing Capacity ◽  
Buried Structures ◽  
Load Bearing ◽  
Under Construction ◽  
Foundation Plate

The problem of strengthening weak or overloaded bases is an important objective of underground space development. It is especially urgent if there are alternating weak layers in the base. The paper presents a practical geotechnical case of strengthening the overloaded base of a reinforced concrete foundation plate for a 25-storey residential building under construction. Combined soil piles that consist of Jet (type 1) soil concrete piles reinforced along the longitudinal axis with drilled injection piles made by electric discharge technology (EDT piles) are used as buried structures. This method of arrangement of a combined buried reinforced concrete structure is conditioned by the need to increase the load-bearing capacity of a pile in soil by two or more times.

Calculation Model of a Complex Stress Reinforced Concrete Element of a Boxed Section During Torsion with Bending

2021 ◽  
pp. 9-26
Author(s):  
Н. И. Карпенко ◽  
Вл. И. Колчунов ◽  
В. И. Травуш
Keyword(s):  
Reinforced Concrete ◽  
Residential Building ◽  
High Strength ◽  
Complex Stress ◽  
Calculation Model ◽  
Deformation Model ◽  
Concrete Element ◽  
Scientific Publications ◽  
Curvature And Torsion ◽  
Deformation Models

Постановка задачи. На основе анализа отечественных и зарубежных научных публикаций и нормативных документов установлено, что известные деформационные модели для расчета сложнонапряженных железобетонных элементов при кручении с изгибом носят достаточно условный характер. В связи с этим в статье рассматривается решение задачи создания расчетной модели железобетонного элемента при кручении с изгибом в стадии после образования трещин, наиболее полно учитывающей специфику трещинообразования, деформирования и разрушения таких элементов. Рассмотрен случай, когда из возможных внешних воздействий наибольшее влияние на напряженно-деформированное состояние оказывает действие крутящего и изгибающего моментов. Результаты. На основе уравнений статики и физических соотношений железобетона определены расчетные параметры, такие как напряжения в бетоне сжатой зоны, высота сжатого бетона, напряжения в хомутах, деформации в бетоне и арматуре, кривизна и угол закручивания железобетонного элемента. Выводы. Полученные аналитические зависимости апробированы численным расчетом железобетонного обвязочного ригеля наружного контура жилого здания коробчатого сечения из высокопрочного бетона. Предложенная деформационная модель может быть использована при проектировании широкого класса железобетонных конструкций, работающих на изгиб с кручением. Statement of the problem. Based on the analysis of domestic and foreign scientific publications and guidelines, it is found that the known deformation models for the calculation of complex tensile reinforced concrete elements during torsional bending are quite conditional. Therefore the article considers the solution of the problem of designing a computational model of a reinforced concrete element during torsion with bending in the post-crack stage, which most fully accounts for the specifics of crack formation, deformation and destruction of such elements. The case is considered for when among all possible external influences the action of torques and bending moments has the greatest influence on the stress-strain. Results. Using the equations of statics and physical ratios of reinforced concrete, the calculated parameters are identified such as stresses in concrete of compressed zone, height of compressed concrete, stresses in clamps, deformations in concrete and reinforcement, curvature and torsion angle of reinforced concrete element. Conclusions. The obtained analytical dependences were tested by means of numerical calculation of the reinforced concrete strapping crossbar of the outer contour of a residential building of box section of high-strength concrete. The suggested deformation model can be employed in the design of a wide class of reinforced concrete structures working on torsional bending.

scholarly journals Value of Information (VoI) for the Chloride Content in Reinforced Concrete Bridges

2020 ◽  
Vol 10 (2) ◽  
pp. 567
Author(s):  
Ivan Zambon ◽  
Monica Patricia Santamaria Ariza ◽  
José Campos e Matos ◽  
Alfred Strauss
Keyword(s):  
Reinforced Concrete ◽  
Minimum Cost ◽  
Cost Effective ◽  
Chloride Content ◽  
Concrete Bridges ◽  
Chloride Ingress ◽  
Maximum Cost ◽  
Initiation Phase ◽  
Reinforced Concrete Bridges ◽  
The Cost

The corrosion of reinforcement caused by chloride ingress significantly reduces the length of the service life of reinforced concrete bridges. Therefore, the condition of bridges is periodically inspected by specially trained engineers regarding the possible occurrence of reinforcement corrosion. Their main goal is to ensure that the structure can resist mechanical and environmental loads and offer a satisfactory level of safety and serviceability. In the course of assessment, measuring the chloride content, through which corrosion could be anticipated and prevented, presents a possible alternative to visual inspections and corrosion tests that can only indicate already existing corrosion. It is hard to determine the cost-effectiveness and actual value of chloride content measurements in a simple and straightforward way. Thus, the main aim of the paper was to study the value of newly gained information, which is obtained when a chloride content in reinforced concrete bridges is measured. This value was here analyzed through the pre-posterior analysis of the cost of measurement and repair, taking into account different types of exposure and material properties for a general case. The research focus was set on the initiation phase in which there are no visible damages. A relative comparison of costs is presented, where the cost of possible reactive/proactive repair was compared with the maximum cost of measurement, while the measurement is still cost effective. The analysis showed a high influence of the initial probability of depassivation on the maximum cost of the cost-effective measurement, as well as a nonreciprocal relation of the minimum cost of cost-effective reactive repair with the measurement accuracy.

Research on Bearing Capacity of Axiallycompressed Short Columns

2013 ◽  
Vol 405-408 ◽  
pp. 958-963 ◽  
Author(s):  
Ying Zi Yin ◽  
Yan Zhang ◽  
Gen Tian Zhao
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
High Strength Concrete ◽  
High Strength ◽  
Reinforced Concrete Structure ◽  
Design Specification ◽  
Steel Reinforced Concrete ◽  
Strength Concrete ◽  
Short Columns ◽  
High Building

Abstract: Steel reinforced concrete structure (SRC) is commonly used in high building, but the research on properties of steel reinforced high strength concrete structure (HSRC) composed of high strength concrete and steel reinforced concrete is rarely carried out. In this paper, a series of problems in HSRC structure application is studied, including the steel radio, the stirrup ratio. The conclusions can be served for design specification of steel reinforced high strength concrete column

scholarly journals CALCULATION MODEL OF A COMPLEX STRESS REINFORCED CONCRETE ELEMENT OF A BOXED SECTION DURING TORSION WITH BENDING

2021 ◽  
pp. 7-26
Author(s):  
N. I. Karpenko ◽  
Vl. I. Kolchunov ◽  
V. I. Travush
Keyword(s):  
Reinforced Concrete ◽  
Residential Building ◽  
High Strength ◽  
Complex Stress ◽  
Calculation Model ◽  
Deformation Model ◽  
Concrete Element ◽  
Scientific Publications ◽  
Curvature And Torsion ◽  
Deformation Models

Statement of the problem. Based on the analysis of domestic and foreign scientific publications and guidelines, it is found that the known deformation models for the calculation of complex tensile reinforced concrete elements during torsional bending are quite conditional. Therefore the article considers the solution of the problem of designing a computational model of a reinforced concrete element during torsion with bending in the post-crack stage, which most fully accounts for the specifics of crack formation, deformation and destruction of such elements. The case is considered for when among all possible external influences the action of torques and bending moments has the greatest influence on the stress-strain. Results. Using the equations of statics and physical ratios of reinforced concrete, the calculated parameters are identified such as stresses in concrete of compressed zone, height of compressed concrete, stresses in clamps, deformations in concrete and reinforcement, curvature and torsion angle of reinforced concrete element. Conclusions. The obtained analytical dependences were tested by means of numerical calculation of the reinforced concrete strapping crossbar of the outer contour of a residential building of box section of high-strength concrete. The suggested deformation model can be employed in the design of a wide class of reinforced concrete structures working on torsional bending.

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