scholarly journals Fire resistance of concrete walls with light aggregate

2018 ◽  
Vol 9 (4) ◽  
pp. 319-341 ◽  
Author(s):  
Kristian Hertz
Keyword(s):  
Bearing Capacity ◽  
Concrete Columns ◽  
Design Methods ◽  
Full Scale ◽  
Fire Exposure ◽  
Load Bearing Capacity ◽  
Concrete Walls ◽  
Aggregate Concrete ◽  
Content Type ◽  
Full Scale Tests

Purpose The purpose of this paper is to present the design methods for fire-exposed concrete columns and walls. In addition, it presents analyses and tests showing that the methods are applicable for designing columns and walls of lightweight aggregate concrete based on expanded clay aggregate as well as heavy normal weight concrete and that the methods fit smoothly with cold design, when the fire exposure varies towards no fire. Design/methodology/approach During the 1990s, some of these design methods were included in the Eurocode as “the zone method”. They are still a part of the code. The rest of the methods, which were not included, served in practice, teaching and research. The present paper derives calculation methods proving their connection with common design for load cases without fire exposure. Furthermore, the paper presents full-scale tests proving the validation of the design methods for structural members of light aggregate concrete in addition to the full-scale tests of heavy concrete members. Findings The design methods give correct estimates of the load-bearing capacity of eccentric loaded concrete columns. An extended version of the methods estimates load-bearing capacity for walls with fire exposure on one side with sufficient accuracy for the purpose of design. Originality/value The author developed the main parts of the design methods in the 1980s and 1990s and others have from time to time referred to some parts of them mainly the minor parts published in the Eurocodes. However, owing to work overload, the author has not published the derivation and verification of them before. This paper provides in particular a verification against full-scale tests of light-aggregate concrete walls not published before.

Experimental Study on All-Lightweight Aggregate Concrete Columns under Eccentric Loading

2012 ◽  
Vol 517 ◽  
pp. 392-397
Author(s):  
Yan Min Yang ◽  
Hao Zhang
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Lightweight Aggregate ◽  
Concrete Columns ◽  
Lightweight Aggregate Concrete ◽  
Fine Aggregate ◽  
Mechanical Behaviors ◽  
Load Bearing Capacity ◽  
Aggregate Concrete ◽  
Load Bearing

A kind of lightweight sand was only used as the fine aggregate to make the all-lightweight aggregate concrete, which can significantly reduce the gravity load of a structure and the foundation loads. Accordingly, the application of all-lightweight aggregate concrete in the construction projects can reduce the cost of foundation as well as construction project. In order to develop a new multi-story structural system which has a multifunction of load-bearing, lightweight and energy saving, the paper carried out an experimental study on the mechanical behaviors of six all-lightweight aggregate concrete columns with symmetrical reinforcement under eccentric loading. The failure modes, deformation characteristics and load-bearing capacity of the columns were analyzed. The effect of reinforcement ratio, stirrup ratio and eccentricity on the mechanical behaviors of the columns under eccentric loading were discussed. The test results show that all-lightweight aggregate concrete columns were loaded to failure with high load-bearing capacity and good ductility. The excellent mechanical behavior and the possibility of replacing the normal concrete with all-lightweight aggregate concrete were verified.

Experimental Research on Behavior of CFRP Circular Steel Tubular Confined Recycled Aggregate Concrete Columns under Axial Compression

2015 ◽  
Vol 744-746 ◽  
pp. 96-99
Author(s):  
Jiong Feng Liang ◽  
Ze Ping Yang ◽  
Ming Hua Hu
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Concrete Columns ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Compression Tests ◽  
Load Bearing Capacity ◽  
Aggregate Concrete ◽  
Load Bearing ◽  
Cfrp Wrapping

In order to further promote the use of recycled aggregate concrete in practice, axial compression tests were carried out for 7 CFRP circular steel tubular confined recycled aggregate concrete columns. The influence of the replace rate of recycled aggregate concrete, the wrapping method on axial compression behavior of CFRP circular steel tubular confined recycled aggregate concrete columns were analyzed. Based on the results of the tests, with the replace rate of recycled aggregate concrete increasing, the specimens have an decreasing trend in the load bearing capacity. The whole CFRP wrapping circular steel tubular confined recycled aggregate concrete columns have higher load bearing capacity than the three stripe wrapping ones.

scholarly journals ANALYTICAL AND NUMERICAL METHODS FOR DETERMINING THE CARRYING CAPACITY OF A PILE BARETT ON WEAK SOILS IN DEEP PITS

2021 ◽  
Vol 17 (3) ◽  
pp. 94-101
Author(s):  
Rashid Mangushev ◽  
Nadezhda Nikitina ◽  
Hieu Le Trung ◽  
Ivan Tereshchenko
Keyword(s):  
Bearing Capacity ◽  
Numerical Test ◽  
Full Scale ◽  
Construction Site ◽  
Weak Soils ◽  
Geological Conditions ◽  
Full Scale Tests ◽  
Soil Excavation ◽  
Deep Pits ◽  
The City

The article provides an analysis of the bearing capacity of barrett piles in difficult geological conditions at a construction site in the city of Hanoi, Vietnam based on the results of analytical calculations according to Russian building codes, mathematical modeling and field full-scale tests. The paper describes a numerical test of a single barrette for Mohr-Coulomb and Hardening Soil models in the Midas GTS NX software package. The bearing capacity of a barrette in soft soils is also proposed to be determined by an analytical solution for calculating the settlement of a single pile, taking into account the unloading of the pit after soil excavation. The results of full-scale tests at the site of future construction, graphs of "load-settlement" of the barrette head from the applied vertical load and the general assessment of the bearing capacity of the barret pile by various methods are shown.

scholarly journals Applying the dimensional method for valuation of the strength loss of cement compositions exposed to elevated temperatures

2018 ◽  
Vol 251 ◽  
pp. 02005
Author(s):  
Nikita Levashov ◽  
Marina Akulova ◽  
Olga Potemkina ◽  
Alla Sokolova ◽  
Yulia Sokolova
Keyword(s):  
Experimental Data ◽  
Bearing Capacity ◽  
Fire Resistance ◽  
Elevated Temperatures ◽  
Classical Method ◽  
Strength Loss ◽  
Ultimate State ◽  
Load Bearing Capacity ◽  
Full Scale Tests ◽  
Loss Of Strength

The paper presents the basis of the analytical model for calcu-lating the loss of strength in ce-ment compositions exposed to elevated temperatures. This model is to replace the classical method of calculating the fire resistance of the loss of load-bearing capacity. The experimental data were taken as initial indicators. Based on the implemented calculations it would become possible to predict the occurrence of ultimate state by loss strength and the reliability of practical indicators obtained by means of full-scale tests

Load-bearing capacity of plain concrete walls

2009 ◽  
Vol 61 (3) ◽  
pp. 173-182 ◽  
Author(s):  
J. Hegger ◽  
T. Dressen ◽  
N. Will
Keyword(s):  
Bearing Capacity ◽  
Plain Concrete ◽  
Load Bearing Capacity ◽  
Concrete Walls ◽  
Load Bearing

Experimental determination of the residual compressive strength of concrete columns subjected to different fire durations and load ratios

2020 ◽  
Vol 11 (4) ◽  
pp. 529-543
Author(s):  
Anjaly Nair ◽  
Osama (Sam) Salem
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Concrete Columns ◽  
Fire Exposure ◽  
Fire Performance ◽  
Content Type ◽  
Residual Compressive Strength ◽  
Standard Fire ◽  
Strength Capacity

Purpose At elevated temperatures, concrete undergoes changes in its mechanical and thermal properties, which mainly cause degradation of strength and eventually may lead to the failure of the structure. Retrofitting is a desirable option to rehabilitate fire damaged concrete structures. However, to ensure safe reuse of fire-exposed buildings and to adopt proper retrofitting methods, it is essential to evaluate the residual load-bearing capacity of such fire-damaged reinforced concrete structures. The focus of the experimental study presented in this paper aims to investigate the fire performance of concrete columns exposed to a standard fire, and then evaluate its residual compressive strengths after fire exposure of different durations. Design/methodology/approach To effectively study the fire performance of such columns, eight identical 200 × 200 × 1,500-mm high reinforced concrete columns test specimens were subjected to two different fire exposure (1- and 2-h) while being loaded with two different load ratios (20% and 40% of the column ultimate design axial compressive load). In a subsequent stage and after complete cooling down, residual compressive strength capacity tests were performed on each fire exposed column. Findings Experimental results revealed that the columns never regain its original capacity after being subjected to a standard fire and that the residual compressive strength capacity dropped to almost 50% and 30% of its ambient temperature capacity for the columns exposed to 1- and 2-h fire durations, respectively. It was also noticed that, for the tested columns, the applied load ratio has much less effect on the column’s residual compressive strength compared to that of the fire duration. Originality/value According to the unique outcomes of this experimental study and, as the fire-damaged concrete columns possessed considerable residual compressive strength, in particular those exposed to shorter fire duration, it is anticipated that with proper retrofitting techniques such as fiber-reinforced polymers (FRP) wrapping, the fire-damaged columns can be rehabilitated to regain at least portion of its lost load-bearing capacities. Accordingly, the residual compressive resistance data obtained from this study can be effectively used but not directly to adopt optimal retrofitting strategies for such fire-damaged concrete columns, as well as to be used in validating numerical models that can be usefully used to account for the thermally-induced degradation of the mechanical properties of concrete material and ultimately predict the residual compressive strengths and deformations of concrete columns subjected to different load intensity ratios for various fire durations.

Experimental Study on Axial Compression Performance of Full-Scale Square Columns of Reinforced Concrete Confined by High-Strength Reinforcement Hoops

2012 ◽  
Vol 446-449 ◽  
pp. 981-988
Author(s):  
Zhen Bao Li ◽  
Wen Jing Wang ◽  
Wei Jing Zhang ◽  
Yun Da Shao ◽  
Bing Zhang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Yield Strength ◽  
Bearing Capacity ◽  
Axial Compression ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Full Scale ◽  
Compression Performance ◽  
Deformation Ability

Axial compression experiments of four full-scale reinforced concrete columns of two groups were carried out. One group of three columns used high-strength steel with the yield strength of 1000MPa as reinforcement hoops, and the second group used the ordinary-strength steel with yield strength of 400MPa. The axial compressive performances between these two groups were assessed. Compared to the specimen using the ordinary-strength steel, the axial compressive bearing capacity of using the high strength steel dose not increase significantly, while the deformation ability increases greatly. The results also indicate that the stress redistributions of the hoops and the concrete sections are obvious, and long-lasting when specimens achieve the ultimate bearing capacity after the yield of the rebar and local damage of concrete materials, at this time the strain of the specimens developes a lot, especially stress - strain curves of speciments with high-strength hoop all show a wide and flat top.

Glass Columns under Impact - Experimental and Numerical Analyses

2017 ◽  
Vol 755 ◽  
pp. 82-89
Author(s):  
Chiara Bedon ◽  
Roman Kalamar ◽  
Martina Eliášová
Keyword(s):  
Bearing Capacity ◽  
Numerical Models ◽  
Construction Materials ◽  
Careful Consideration ◽  
Full Scale ◽  
Structural Glass ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Glass Columns ◽  
Traditional Construction

Compared to traditional construction materials, structural glass members subjected to main compression are relatively unusual in buildings, despite a substantially high material compressive strength. The major limit for the use of glass columns is in fact represented by an overall residual load-bearing capacity highly affected by the tensile brittle fracture of glass. An optimal and fail-safe design approach, in this regard, should take care of a multitude of geometrical and mechanical aspects, including boundary details and possible defects, as well as accidental loading scenarios. Aiming to assess the feasibility and vulnerability of structural glass members, based on earlier research efforts, the paper deals on the load-bearing performance of a reference set of full-scale glass columns. Careful consideration is in fact paid for the experimental investigation of glass members with square hollow cross-section and subjected to dynamic impacts, being representative of an accidental loading scenario. Full-scale experimental results are presented, as well as further considered for validation and calibration of Finite Element (FE) numerical models accounting for possible damage propagation in all the structural components, hence allowing to assess the residual load-bearing capacity of the examined structural typology.

scholarly journals Mechanical Properties of Concrete Pipes with Pre-Existing Cracks

2020 ◽  
Vol 10 (4) ◽  
pp. 1545
Author(s):  
Zongyuan Zhang ◽  
Hongyuan Fang ◽  
Bin Li ◽  
Fuming Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Bearing Capacity ◽  
Three Dimensional ◽  
Compressive Load ◽  
Full Scale ◽  
Element Analysis ◽  
Concrete Pipes ◽  
Concrete Pipe ◽  
Full Scale Tests

Concrete pipes are the most widely used municipal drainage pipes in China. When concrete pipes fall into years of disrepair, numerous problems appear. As one of the most common problems of concrete pipes, cracks impact on the deterioration of mechanical properties of pipes, which cannot be ignored. In the current work, normal concrete pipes and those with pre-existing cracks are tested on a full scale under an external compressive load. The effects of the length, depth, and location of cracks on the bearing capacity and mechanical properties of the concrete pipes are quantitatively analyzed. Based on the full-scale tests, three-dimensional finite element models of normal and cracked concrete pipes are developed, and the measured results are compared with the data of the finite element analysis. It is clear that the test measurements are in good agreement with the simulation results; the bearing capacity of a concrete pipe is inversely proportional to the length and depth of the crack, and the maximum circumferential strain of the pipe occurs at the location of the crack. The strain of the concrete pipe also reveals three stages of elasticity, plasticity, and failure as the external load rises. Finally, when the load series reaches the limit of the failure load of the concrete pipe with pre-existing cracks, the pipe breaks along the crack position.

Experimental Research on Full-Scale Reinforced Concrete Columns with Strong Confinement under Concentric Compression

2012 ◽  
Vol 166-169 ◽  
pp. 836-842
Author(s):  
Wei Jing Zhang ◽  
Bing Zhang ◽  
Zhen Bao Li ◽  
Jinjin Wang ◽  
Wen Jing Wang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Columns ◽  
Full Scale ◽  
Tensile Yield Strength ◽  
Reinforced Concrete Columns ◽  
The Core ◽  
Deformation Ability ◽  
Strong Confinement ◽  
Core Concrete

To investigate the axial compressive behavior of reinforced concrete columns with strong confinement, a total of five full-scale reinforced concrete columns with stirrup characteristic values in the range 0.22~0.47 and section dimension 600mm×600mm were tested under concentric compression loading. The test results indicated that all specimens failed in a similar way. The longitudinal bars buckled in compression; the peripheral stirrups bowed out and several stirrups fractured; the cover concrete in the mid-height section of specimens spalled seriously; however, the core concrete of specimens was not crushed. The axial compressive bearing capacity and deformation ability of reinforced concrete columns could be improved by strong confinement. When specimens reached the ultimate bearing capacity, the longitudinal reinforcement yielded and provided axial bearing capacity for specimens; the transverse reinforcement reached tensile yield strength and provided effective confinement for the core concrete.

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