scholarly journals Design analysis of strengthening a damaged supporting structure in a swimming pool building

2019 ◽  
Author(s):  
Leopold Kruszka ◽  
Ryszard Chmielewski
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Structural Damage ◽  
Strength Class ◽  
Construction Material ◽  
Technical Condition ◽  
Swimming Pool ◽  
Reinforcing Bars ◽  
Total Load ◽  
Supporting Structure

The issue of strengthening the supporting structure of the swimming pool building, with a special attention on damaged reinforced concrete pillars in the sub-pool, is presented. The technical condition of those pillars in the basement of the swimming pool was defined as the risk of structural collapse. Numerous cracks and the occurrence of deformation of reinforcing bars were noticed. Three columns were damaged in basement rooms. First of all, the cause of damage was determined. The actual load carrying capacity of the built pillars was checked. To this aim, the geometry of the columns was checked first and the actual strength class of built-in concrete. It was found that all columns were made of concrete of the same strength class and good homogeneity of concrete, but this concrete did not meet the standard requirements as a construction material for reinforced concrete structures. The new supporting structure was designed in the form of four-leg cross-sections made of an isosceles angle profile. Due to structural damage, an additional safety factor was adopted, increasing the total load per pillar by 50%. This approach took into account the possible redistribution of loads in the building structure that occurred as a result of damages.

scholarly journals Initial crack effect on the strength of oblique cross sections of reinforced concrete beams strengthened with carbon fiber

2019 ◽  
Vol 110 ◽  
pp. 01053
Author(s):  
Alexandr Shilov ◽  
Petr Polskoy ◽  
Dmitriy Mailyan ◽  
Petr Shilov
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Cross Sections ◽  
Structural Damage ◽  
Concrete Beams ◽  
Experimental Studies ◽  
Reinforced Concrete Beams ◽  
Shear Span ◽  
The Impact ◽  
Initial Cracks

In the theory of reinforced concrete, the issue on strength of the oblique beam sections is more complicated than that on the standard sections, since it depends on many factors. The change of at least one of them leads to a significant change in the carrying capacity and in the structural damage pattern. This is due to the fact that at the operating level of the load, all conventional reinforced concrete structures work with cracks, which must be considered in the calculation. However, in the existing regulatory documents and public sources, this issue is not specified. This paper considers the effect of initial cracks on the strength of oblique cross sections of the reinforced concrete beams strengthened with carbon fiber. The experimental studies results obtained through the transverse force testing of forty-two prototypes made of heavy concrete of B30 design grade are presented. The test samples had initial oblique cracks of 0.6-0.9 mm width and were reinforced with three composite U stirrups from the fabric based on unidirectional carbon fibers in the shear span. Initial cracks in the beams were formed at three values of the shear span – 1.5h0, 2h0 and 2.5h0. The test data show the impact of initial cracks on the efficiency of composite reinforcement of oblique cross sections of the prototypes at various values of shear spans.

scholarly journals Statistical and Reliability Study on Shear Strength of Recycled Coarse Aggregate Reinforced Concrete Beams

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3321
Author(s):  
Hyunjin Ju ◽  
Meirzhan Yerzhanov ◽  
Alina Serik ◽  
Deuckhang Lee ◽  
Jong R. Kim
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Construction Material ◽  
Safety Margin ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Rc Structures ◽  
Coarse Aggregates

The consumption of structural concrete in the construction industry is rapidly growing, and concrete will remain the main construction material for increasing urbanization all over the world in the near future. Meanwhile, construction and demolition waste from concrete structures is also leading to a significant environmental problem. Therefore, a proper sustainable solution is needed to address this environmental concern. One of the solutions can be using recycled coarse aggregates (RCA) in reinforced concrete (RC) structures. Extensive research has been conducted in this area in recent years. However, the usage of RCA concrete in the industry is still limited due to the absence of structural regulations appropriate to the RCA concrete. This study addresses a safety margin of RCA concrete beams in terms of shear capacity which is comparable to natural coarse aggregates (NCA) concrete beams. To this end, a database for reinforced concrete beams made of recycled coarse aggregates with and without shear reinforcement was established, collecting the shear specimens available from various works in the existing literature. The database was used to statistically identify the strength margin between RCA and NCA concrete beams and to calculate its safety margin based on reliability analysis. Moreover, a comparability study of RCA beams was conducted with its control specimens and with a database for conventional RC beams.

Analysis of Reinforced Concrete Culvert considering Concrete Creep and Shrinkage

1996 ◽  
Vol 1541 (1) ◽  
pp. 120-126
Author(s):  
Charles J. Oswald
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Cross Sections ◽  
Soil Structure ◽  
Silty Clay ◽  
Soil Pressure ◽  
Concrete Creep ◽  
Long Span ◽  
Creep And Shrinkage ◽  
Good Agreement

Measurements made on a long span reinforced concrete arch culvert under 7.3 m (24 ft) of silty clay backfill were compared with results from finite-element analyses of the soil-structure system using the CANDE finite-element code. The culvert strains and deflections and the soil pressure on the culvert were measured during construction and during the following 2.5 years at three instrumented cross sections. The CANDE program was modified to account for the effects of concrete creep and shrinkage strains after it was noted that the measured postconstruction culvert deflection and strains increased significantly whereas the measured soil pressure on the culvert remained relatively constant. Good agreement was generally obtained between measured and calculated values of the culvert strain and deflection and the soil pressure during the entire monitoring period after the code was modified.

Closed-form moment-curvature relations for reinforced concrete cross sections under bending moment and axial force

2016 ◽  
Vol 129 ◽  
pp. 67-80 ◽  
Author(s):  
Pedro Dias Simão ◽  
Helena Barros ◽  
Carla Costa Ferreira ◽  
Tatiana Marques
Keyword(s):  
Reinforced Concrete ◽  
Closed Form ◽  
Axial Force ◽  
Cross Sections ◽  
Bending Moment

Experimental of Inverted-T Shape Reinforced Concrete Wall Subjected to Blast Load

2021 ◽  
Vol 879 ◽  
pp. 254-262
Author(s):  
Mazlan Abu Seman ◽  
Sharifah Maszura Syed Mohsin ◽  
Ahmad Mujahid Ahmad Zaidi ◽  
Md Fuad Shah Koslan ◽  
Zainorizuan Mohd Jaini
Keyword(s):  
Reinforced Concrete ◽  
Blast Resistance ◽  
Retaining Wall ◽  
Construction Material ◽  
High Strength ◽  
Steel Reinforcement ◽  
Blast Load ◽  
Structural Element ◽  
Concrete Wall ◽  
Flexural Reinforcement

Reinforced concrete (RC) widely used as the construction material for the main structural element for many significant structures such as bridge and building because of its relatively high strength and economical. However, there still lacks research published regarding the appropriate reinforcement steel arrangement in a complete RC structure subjected to blast load. Most of the published experimental works focused on the small rectangular or square RC panel. From the record search, the approved design by professional engineers, when RC wall subjected to the possibility of blast load, both RC wall details either retaining wall or shear wall implemented. Therefore, the full-scale blast experiment is vital to appraise the appropriate steel reinforcement arrangement in the RC wall. The blast experiment indicated, with different steel reinforcement arrangement in the RC wall, the better blast resistance with the number of cracks on the RC wall is significantly less from one another for the wall with the arrangement of horizontal flexural reinforcement tied-outside the vertical flexural reinforcement and the hooked-in direction of vertical flexural steel reinforcement into the wall base.

The Lima earthquake of October 3, 1974: Damage distribution

1977 ◽  
Vol 67 (5) ◽  
pp. 1441-1472
Author(s):  
R. Husid ◽  
A. F. Espinosa ◽  
J. de las Casas
Keyword(s):  
Reinforced Concrete ◽  
Structural Damage ◽  
Concrete Structures ◽  
Effective Length ◽  
Reinforced Concrete Structures ◽  
Severe Damage ◽  
Original Design ◽  
Reinforced Masonry ◽  
Water Tanks ◽  
Story Building

abstract The October 3, 1974, earthquake caused severe damage to buildings of adobe and quincha construction, and also to masonry, reinforced masonry, and reinforced-concrete structures in Lima and vicinity. Most of the damage to well-built structures was due, in part, to the lack of lateral resistance in the original design and to the fact that this earthquake had more energy around 0.4 seconds period than prior destructive earthquakes. Water tanks on the roofs of structures with four or five stories were damaged. Well-engineered single-story buildings were less affected than taller structures. Considerable structural damage to reinforced-concrete structures occurred in the districts of Barranco, La Campiña Molina, and Callao. In La Campiña three-story building partly collapsed and other buildings sustained considerable damage. In La Molina, the buildings of the Agrarian University sustained severe damage, and some collapsed. In Surco, the district adjacent to La Molina, there was no appreciable damage. In Callao, a four-story building collapsed, and the upper half of a concrete silo collapsed. In reinforced-concrete structures, column ties were frequently small in diameter, widely spaced, and not well connected. Usually, the reinforcement of resisting elements had no relation to their stiffnesses. Front columns in school buildings were restrained by high brick walls and had rather short effective lengths to allow building displacement in that direction. The windows in the rear walls gave the rear columns a much greater effective length. Therefore, a longitudinal displacement induces large shear forces in the front columns where most of the severe damage occurred. This problem was not considered in the design of these structures.

Experimental Study on the Structural Performance of Beam-Column Joints in Old Buildings without Designed Shear Reinforcement under Earthquake

2017 ◽  
Vol 902 ◽  
pp. 33-40
Author(s):  
Cong Thuat Dang ◽  
Ngoc Hieu Dinh
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Test Results ◽  
Shear Reinforcement ◽  
Reinforcing Bars ◽  
Reinforced Concrete Buildings ◽  
Concrete Buildings ◽  
Gravity Load ◽  
Load Beam

Old reinforced concrete buildings constructed around 1980’s in many developing countries have been designed against mainly gravity load. Beam-column joints in these buildings contain slightly or no shear reinforcement inside the panel zones due to the construction convenience, and are vulnerable to shear failure in beam-column joints under the action of earthquake loads, especially for the exterior beam-column joints. This experimental study aimed to investigate the seismic performance of five half-scale exterior beam-column joints simulating the joints in existing reinforced-concrete buildings with non-shear hoop details. The test results showed that the structural performances of the beam-column joints under earthquake including failure mode, load-drift ratio relationship, shear strain of the joints and energy dissipation are strongly affected by the amount of longitudinal reinforcing bars of beams.

Flexural Performance Evaluation of Fiber-Reinforced Concrete Incorporating Multiple Macro-Synthetic Fibers

2018 ◽  
Vol 2672 (27) ◽  
pp. 1-12 ◽  
Author(s):  
Michael Dopko ◽  
Meysam Najimi ◽  
Behrouz Shafei ◽  
Xuhao Wang ◽  
Peter Taylor ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Residual Strength ◽  
Performance Enhancement ◽  
Construction Material ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Test Beam ◽  
Synthetic Fibers ◽  
Flexural Performance ◽  
Strength And Toughness

Fiber-reinforced concrete (FRC) is a promising construction material mainly because of the crack-controlling mechanisms that discrete fibers can impart to inherently brittle concrete. Macrofibers, in particular, have been proven effective for providing post-crack ductility and toughness, while synthetic fibers are a promising solution to avoid corrosion-related durability issues. To assess the performance enhancement provided by macro-synthetic concrete fibers, this study performs flexural tests on FRC beams containing three different types of macro-synthetic fibers. The selected fibers include polypropylene (PP), polyvinyl alcohol (PVA), and alkali-resistant glass (ARG) macrofibers mixed at volume fractions of 0.5%, 1.0%, and 1.5%. Static and dynamic fresh properties are monitored using the vibrating Kelly ball (VKelly) test. Beam specimens are then placed under a third point bending configuration, as per ASTM C1609 Standard, to measure load versus mid-span deflection. Strength and toughness parameters are derived from the load–deflection data to assess the flexural performance of the FRC composite systems under consideration. The parameters of interest include first peak strength (pre-crack flexural strength) and post-crack residual strength and toughness provided by fiber addition. Of the mixtures tested, ARG fiber mixtures show the highest residual strength and toughness values, followed by PP and PVA fiber mixtures. ARG fibers produce the most workable mixtures at all fiber volumes, while PVA fibers show a tendency to encounter dispersion issues at higher volume doses. The outcome of this study is expected to facilitate the selection of fibers by giving insight into their relative contribution to fresh and hardened flexural properties of FRC.

Designing Compressed Reinforcement Cross-Sections by Curvature and Nominal Stiffness Methods

2015 ◽  
Vol 797 ◽  
pp. 69-78
Author(s):  
Krzysztof Kamiński ◽  
Piotr Nowicki
Keyword(s):  
Reinforced Concrete ◽  
Comparative Analysis ◽  
Cross Sections ◽  
Concrete Columns ◽  
Computer Programs ◽  
Significant Issue ◽  
Reinforced Concrete Columns ◽  
Small Eccentricity ◽  
Standard Methods ◽  
Surface Reinforcement

The paper attempts to discuss the still significant issue of methods of design of the reinforced concrete columns according to PN-EN 1992-1-1:2008/A1:2015-03. Two algorithms of the dimensioning sections were developed according to two standard methods of dimensioning eccentrically compressed sections: the method of nominal stiffness (NS) and the method of nominal curvature (NC). Using both algorithms, computer programs in Excel were created. A comparative analysis of several examples of calculation were performed to compare the results of dimensioning of sections eccentrically compressed. The results obtained by the NC method give about 10% less surface reinforcement when loaded with big eccentricity and over 50% less when small eccentricity is applied.

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