scholarly journals Mechanical Behavior and Calculation Method for RC Fifteen-Pile Cap of Mixed Passenger and Freight Railway Bridge

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Hongmeng Huang ◽  
Lu Cui ◽  
Wei Lu
Keyword(s):  
Mechanical Behavior ◽  
Bearing Capacity ◽  
Calculation Method ◽  
Concrete Strength ◽  
Reaction Force ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Strength Grade ◽  
Truss Model ◽  
Diameter Range

The thickness, reinforcement, and concrete strength grade of railway caps in China are generally determined according to the force, yet the method for calculating the force is unclear. To date, there is no desirable calculation method for analyzing the caps. Based on the fifteen-pile thick cap of mixed passenger and freight railway, the influencing factors on cap bearing capacity were analyzed using finite element method (FEM). The variations of load-bearing capacity and mechanical behavior of thick cap were characterized by introducing rigid angle α. Results indicated that ultimate load-bearing value of the cap increased linearly with the increase of concrete strength grade, and an increasing load-bearing capacity of the reinforcement distributed in the pile diameter range was larger than that of the uniform reinforcement; when the reinforcement ratio was 0.15%, it increased by 9.3%. The cap showed punching failure when α < 45°. The reaction force at each pile top under vertical load was not equal; thereby, the cap was not absolutely rigid. The principal compressive stress trajectories in the concrete were distributed in the range of connecting the pile and the outer edge of the pier, and the effective tensile stresses in the reinforcement were mainly distributed in the diameter range of pile and pile connection, which is in accord with the stress mode of the ordinary spatial truss model. Based on this, a spatial truss model applicable to the design of railway caps is proposed, and a method for calculating reaction force at pile top and formulas for calculating the bearing capacity of strut and tie were presented. The feasibility of the proposed method was also verified by comparison with FEM results.

scholarly journals Fire Performance of Columns Made of Normal and High Strength Concrete: A Comparative Analysis

2016 ◽  
Vol 711 ◽  
pp. 564-571 ◽  
Author(s):  
Thomas Gernay
Keyword(s):  
Bearing Capacity ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Strength Loss ◽  
Fire Performance ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Strength Concrete ◽  
The Impact

The use of high strength concrete (HSC) in multi-story buildings has become increasingly popular. Selection of HSC over normal strength concrete (NSC) allows for reducing the dimensions of the columns sections. However, this reduction has consequences on the structural performance in case of fire, as smaller cross sections lead to faster temperature increase in the section core. Besides, HSC experiences higher rates of strength loss with temperature and a higher susceptibility to spalling than NSC. The fire performance of a column can thus be affected by selecting HSC over NSC. This research performs a comparison of the fire performance of HSC and NSC columns, based on numerical simulations by finite element method. The thermal and structural analyses of the columns are conducted with the software SAFIR®. The variation of concrete strength with temperature for the different concrete classes is adopted from Eurocode. Different configurations are compared, including columns with the same load bearing capacity and columns with the same cross section. The relative loss of load bearing capacity during the fire is found to be more pronounced for HSC columns than for NSC columns. The impact on fire resistance rating is discussed. These results suggest that consideration of fire loading limits the opportunities for use of HSC, especially when the objective is to reduce the dimensions of the columns sections.

scholarly journals DEVELOPMENT AND IMPROVEMENT OF BEAM STRUCTURES ON THE BASIS OF COMPOSITE LOGS’ GIRDERS

2018 ◽  
Vol 15 (5) ◽  
pp. 760-773 ◽  
Author(s):  
V. A. Utkin ◽  
P. N. Kobzev ◽  
E. G. Shatunova
Keyword(s):  
Bearing Capacity ◽  
Calculation Method ◽  
Steel Plates ◽  
Load Bearing Capacity ◽  
Beam Structures ◽  
Load Bearing ◽  
Dowel Connections ◽  
Design And Construction ◽  
Composite Girders

Introduction. Experience in the design and construction of beam structures of wooden bridges with composite girders indicates the possibility of increasing the bearing capacity and the length of the overlapped spans.Materials and methods. The most rational load-bearing elements of composite girders can serve as the logs edged on two edges with the diameter of 28 to 32 cm with the maximum use of the most durable layers of sapwood and dowel connections of steel plates with blind cylindrical nags.Results. In contrast to the compounds of composite girders on lamellar nails, the proposed connection greatly simplifies the process of making the composite girders. Such connection also allows using the logging along the length, combining into three or four tiers and increasing the length of the span.Discussion and conclusion. The proposed solutions increase the load-bearing capacity of composite girders and allow them to be used in the structures of wooden bridges under modern automotive loads. Moreover, the calculation method of composite girders on the basis of the method of forces and discrete placement in the beams between the logs of concentrated elastic-datum shear bonds is developed.

Mechanical Behavior of Masonry Specimens Strengthened by Carbon Bundles Subjected to a Splitting Test

2017 ◽  
Vol 747 ◽  
pp. 518-524
Author(s):  
Angelo Di Tommaso ◽  
Susanna Casacci ◽  
Cristina Gentilini
Keyword(s):  
Mechanical Behavior ◽  
Bearing Capacity ◽  
Failure Mechanism ◽  
Initial Crack ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Experimental Campaign ◽  
Splitting Test ◽  
Water Based

In this study the results of an experimental campaign that involves masonry specimens subjected to a purposely designed splitting test are presented. The specimens are reinforced in the mortar joints by means of carbon bundles impregnated with a water based resin. Unreinforced specimens are also tested for comparison purposes. Some specimens are characterized by an initial crack obtained artificially by cutting the bricks to highlight the crack arrestor function of the carbon bundles. Results show that the failure mechanism from brittle becomes ductile and a load bearing capacity increment is registered in reinforced specimens.

scholarly journals DETERMINATION OF THE CRITERIA OF DEFORMATION IN A SPECIAL LIMITING STATE

2021 ◽  
Vol 17 (1) ◽  
pp. 108-116
Author(s):  
Nikolay Trekin ◽  
Emil Kodysh ◽  
Sergey Shmakov ◽  
Tere Terekhov ◽  
Konstantin Kudyakov
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Rational Design ◽  
Progressive Collapse ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Load Bearing Capacity ◽  
Limiting State ◽  
Load Bearing

Constructive measures taken to ensure the integrity of the entire building or its part in emergency situations with design based on the existing criteria of the limiting state method leads to a significantincrease of the construction cost. One of the ways to reduce additional costs of construction while the protection design against progressive collapse is the possible use of additional reserves of deformability of load-bearing elements. It leads to redistribution of loads and the use of non-destroyed structures. It also leads to possible changes of limiting states in non-standard emergency design situations, taking into account the peculiarities of the operation of structures in a special limiting state at a stage close to destruction. In the GOST 27751-2014 «Reliability for constructions and foundations. General principles» calculated states of the firstand second groups of limiting states are given, and for a special limiting state only the area of its permissible application is indicated. The work of reinforced concrete structures at the stage close to the depletion of the load-bearing capacity is little reflectedin the scientificand technical literature; the work of reinforced concrete structures at the unloading stage due to the redistribution of forces is represented in single publications. The article presents theoretical studies based on experimental data on the deformation of bent reinforced concrete beam elements at a stage close to the maximum load-bearing capacity and at the stage of unloading up to the transformation of a structural element into a mechanism. The influenceof the longitudinal reinforcement, the class of reinforcement, prestressing and the concrete strength on the deformation of reinforced concrete bending elements is considered in the article. The research of the behavior of structural elements continuation at this stage is relevant and contributes to the development of economical and rational design solutions for protection against progressive collapse and in the design of earthquake-resistant buildings.

scholarly journals Concrete-filled round-ended steel tubular stub columns under concentric and eccentric loads

2018 ◽  
Author(s):  
Ana Piquer Vicent ◽  
David Hernández-Figueirido ◽  
Carmen Ibáñez Usach
Keyword(s):  
Bearing Capacity ◽  
Mechanical Behaviour ◽  
Mechanical Response ◽  
Concrete Strength ◽  
High Strength ◽  
Load Bearing Capacity ◽  
Cross Sectional ◽  
Load Bearing ◽  
Composite Columns ◽  
Stub Columns

In the past, many works to study the mechanical behaviour of concrete filled steel tubular (CFST) stub columns have been conducted. Some of the applications of these composite columns oblige to meet higher requirements of ductility and load-bearing capacity. Traditionally, circular and rectangular tubes have been employed but recently new cross-sectional shapes of these composite columns are being designed and investigated with the aim of optimizing their mechanical behaviour. In this line, concrete-filled round-ended steel tubular columns (CFRT) have appeared as an alternative. However, the number of experimental programs to characterize their mechanical response is still scarce. In order to contribute to the test results database, in this paper an experimental study of 9 concrete-filled round-ended steel tubular stub columns is presented. All the specimens were designed with the same cross-sectional round-ended shape and have the same dimensions. In this program, both normal and high-strength concrete were employed as infill. During the tests, the columns were subjected to axial compression loads but under different eccentricities. The influence of eccentricity and concrete strength on the ultimate load bearing capacity of the concrete-filled round-ended steel tubular are discussed. Besides, the combined action of both components in this type of concrete-filled tubes as well as the effect of the concrete infill are studied.

Experimental Behavior of Concrete-Filled Square Steel Tube of Mid and Long Columns Subjected to Eccentric Compression

2011 ◽  
Vol 255-260 ◽  
pp. 118-122
Author(s):  
Bin Wang
Keyword(s):  
Experimental Investigation ◽  
Bearing Capacity ◽  
Concrete Strength ◽  
Limit Load ◽  
Steel Tube ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Eccentric Compression ◽  
Experimental Behavior ◽  
Square Steel Tube

This paper presents an experimental investigation of the mechanic behavior of 9 concrete-filled square steel tube columns (CFSST) subjected to eccentric loading. The primary parameters of the specimens are eccentricity ratios, slenderness ratios and concrete strength. The results showed that the eccentricity ratios and slenderness ratios are the primary factors to influence the load-bearing capacity of CFSST columns, with the increase of eccentricity ratios and slenderness ratios, the limit load-bearing capacity reduced gradually. The influence of concrete strength to load-bearing capacity decreased gradually with the increase of eccentricity ratios and slenderness ratios.

scholarly journals STRESS-STRAIN STATE OF PREFABRICATED MONOLITHIC BENDING ELEMENT AT GRADUAL INSTALLATION AND LOADING

2019 ◽  
pp. 101-114
Author(s):  
A. A. Koyankin ◽  
V. M. Mitasov ◽  
I. Ya. Petuhova ◽  
T. A. Tshay
Keyword(s):  
Bearing Capacity ◽  
Strain State ◽  
Concrete Strength ◽  
Experimental Models ◽  
Stress Strain ◽  
Load Bearing Capacity ◽  
Total Load ◽  
Load Bearing ◽  
Regulatory Documents ◽  
Stress Strain State

The stress-strain state of the prefabricated monolithic element depends on its gradual installation and loading. Regulatory documents of the Russian Federation indicate the need to calculate precast-monolithic structures for two stages of construction: before and after the specified monolithic concrete strength acquired. In this case, the stress-strain state that appeared in the prefabricated elements before the specified monolithic concrete strength should be considered.  However, the construction and loading stages at issue and accumulation of stresses and strains are not disclosed in the regulatory documents. In addition, this problem is insufficiently studied.  In this regard, the aim of this paper is to study the pre-loading effect of the prefabricated element on its stress-strain state and the load-bearing capacity.  During the experiments, a pre-loaded prefabricated part is studied. The obtained results are compared with instantaneously loaded test samples. Other parameters of the experimental models are completely identical. In all, 5 samples are tested (step-by-step loading of 3 samples and instantaneous loading of 2 samples).  It is shown that pre-loading of the preloaded prefabricated part significantly affects the stress-strain state of the whole structure and its total load-bearing capacity.  

Post-Tensioned Composite Bridge: Reliability-Based Optimization of Selected Design Parameters

2016 ◽  
Vol 837 ◽  
pp. 38-43
Author(s):  
Ondrej Slowik ◽  
David Lehky ◽  
Martina Somodikova ◽  
Drahomir Novak
Keyword(s):  
Bearing Capacity ◽  
Concrete Strength ◽  
Optimization Method ◽  
Small Sample ◽  
Design Parameters ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Composite Bridge ◽  
Bridge Reliability ◽  
Post Tensioned

In the paper small-sample double-loop optimization method is employed to find selected design parameters of a single-span post-tensioned composite bridge to ensure its reliability and load-bearing capacity. The selected approach consists in nesting the computation of the failure probability with respect to the current design within the optimization loop. The analyzed bridge is made of precast post-tensioned concrete girders, each composed of six segments that are connected by the transverse joints. Bridge spatial deterioration brings uncertainty into actual values of concrete strength in transversal joints and of actual loss of pre-stressing. Due to their significant effect on the bridge load-bearing capacity, both were considered as uncertain design parameters with the aim to find their critical values corresponding to desired reliability level and load-bearing capacity.

Fire resistance of partially encased composite columns subjected to eccentric loading

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abdelkadir Fellouh ◽  
Abdelkader Bougara ◽  
Paulo Piloto ◽  
Nourredine Benlakehal
Keyword(s):  
Bearing Capacity ◽  
Thermal Behaviour ◽  
Analytical Method ◽  
Calculation Method ◽  
Load Capacity ◽  
Simple Calculation ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Content Type ◽  
Composite Column

PurposeInvestigate the fire performance of eccentrically loaded concrete partially encased column (PEC), using the advanced calculation method (ANSYS 18.2, 2017) and the simple calculation method in Annex G of Eurocode 4 (EN 1994-1-2, 2005). This work examines the influence of a range of parameters on fire behaviour of the composite column including: eccentricity loading, slenderness, reinforcement, fire rating and fire scenario. In this study, ISO-834 (ISO834-1, 1999) was used as fire source.Design/methodology/approachCurrently, different methods of analysis used to assess the thermal behaviour of composite column exposed to fire. Analytical method named simplified calculation methods defined in European standard and numerical simulations named advanced calculation models are treated in this paper.FindingsThe load-bearing capacity of the composite column becomes very weak in the presence of the fire accident and eccentric loading, this recommends to avoid as much as possible eccentric loading during the design of construction building. The reinforcement has a slight influence on the temperature evolution; moreover, the reinforcement has a great contribution on the load capacity, especially in combined compression and bending. When only the two concrete sides are exposed to fire, the partially encased composite column presents a high load-bearing capacity value.Originality/valueThe use of a three-dimensional numerical model (ANSYS) allowed to describe easily the thermal behaviour of PEC columns under eccentric loading with the regard to the analytical method, which is based on three complex steps. In this study, the presence of the load eccentricity has found to have more effect on the load-bearing capacity than the slenderness of the composite column. Introducing a load eccentricity on the top of the column may have the same a reducing effect on the load-bearing capacity as the fire.

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