The influence of imperfections on the load bearing capacity of reinforced concrete cantilever columns exposed to fire

2021 ◽  
Vol 121 ◽  
pp. 103294
Author(s):  
Ekkehard Richter ◽  
Jochen Zehfuß
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Load Bearing Capacity ◽  
Load Bearing

Experimental and numerical investigation on the vertical bearing behavior of discrete connected new-type precast reinforced concrete floor system

2020 ◽  
Vol 23 (11) ◽  
pp. 2276-2291
Author(s):  
Rui Pang ◽  
Yibo Zhang ◽  
Longji Dang ◽  
Lanbo Zhang ◽  
Shuting Liang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cover Plate ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Concrete Floor ◽  
New Type ◽  
Vertical Bearing ◽  
Floor System ◽  
Bearing Behavior

This article proposes a new type of discrete connected precast reinforced concrete diaphragm floor system that consists of precast flat slabs and slab joint connectors. An experimental investigation of discrete connected new-type precast reinforced concrete diaphragm under a vertical distributed static load was conducted, and the effect of slab joint connectors on the load-bearing capacity was evaluated. Then, a finite element analysis of discrete connected new-type precast reinforced concrete diaphragm, precast reinforced concrete floors without slab connectors, and cast-in-situ reinforced concrete floor were performed to understand their working mechanism and determine the differences in load-bearing behavior. The results indicate that the load-bearing capacity and stiffness of discrete connected new-type precast reinforced concrete diaphragm increase considerably as the hairpin and cover plate hybrid slab joint connectors can efficiently connect adjacent precast slabs and enable them to work together under a vertical load by transmitting the shear and moment forces in the orthogonal slab laying direction. The deflection of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction is mainly caused by the opening deformation of the slab joint and the rotational deformation of the precast slabs. This flexural deformation feature can provide reference for establishing the bending stiffness analytical model of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction, which is vitally important for foundation of the vertical bearing capacity and deformation calculation method. The deflection and crack distribution patterns infer that the discrete connected new-type precast reinforced concrete diaphragm processes the deformation characteristic of two-way slab floor, which can provide a basis for the theoretical analysis of discrete connected new-type precast reinforced concrete diaphragm.

scholarly journals Load Bearing Capacity Calculation of the System “Reinforced Concrete Beam – Deformable Base” under Torsion with Bending

2019 ◽  
Vol 97 ◽  
pp. 04059 ◽  
Author(s):  
Alexey Dem’yanov ◽  
Vladymir Kolchunov ◽  
Igor Iakovenko ◽  
Anastasiya Kozarez
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Concrete Beam ◽  
Equations Of State ◽  
Reinforced Concrete Beam ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Deformable Base ◽  
The Relationship

It is presented the formulation and solution of the load bearing capacity of statically indeterminable systems “reinforced concrete beam – deformable base” by spatial cross-sections under force and deformation effects. The solution of problem is currently practically absent in general form. It has been established the relationship between stresses and strains of compressed concrete and tensile reinforcement in the form of diagrams. The properties of the base model connections are described based on a variable rigidity coefficient. It is constructed a system of n equations in the form of the initial parameters method with using the modules of the force (strain) action vector. The equations of state are the dependences that establish the relationship between displacements which are acting on the beam with load. Constants of integration are determined by recurrent formulas. It makes possible to obtain the method of initial parameters in the expanded form and, consequently, the method of displacements for calculating statically indefinable systems. The values of the effort obtained could be used to determine the curvature and rigidity of the sections in this way. It is necessary not to set the vector modulusP, the deformation is set in any section (the module is considered as an unknown) during the problem is solving. This allows us to obtain an unambiguous solution even in the case when the dependence M–χ has a downward section, i.e one value of moment can correspond to two values of curvature.

Probabilistic Assessment of Historic Reinforced Concrete Bridge

2016 ◽  
Vol 821 ◽  
pp. 767-773
Author(s):  
Jan Krejsa ◽  
Miroslav Sýkora ◽  
Michal Drahorád
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Probabilistic Method ◽  
Concrete Bridge ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Reinforced Concrete Bridge ◽  
Factor Method ◽  
Partial Factor Method ◽  
Partial Factor

This paper is aimed at the reliability analysis of an existing reinforced concrete bridge from 1908. The load bearing capacity is assessed in accordance with valid standards using the partial factor method and probabilistic approach. Load bearing capacities obtained by these methods are critically compared. The application of probabilistic method leads to 40 % higher load bearing capacity then the partial factor method used for structural design.

scholarly journals Research on Intelligent Evaluation System of Load-bearing Capacity of Existing Reinforced Concrete Bridge

2020 ◽  
Vol 165 ◽  
pp. 04056
Author(s):  
An Zhao ◽  
Qiang Xu ◽  
Jianyong Song
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Evaluation System ◽  
Limit State ◽  
Concrete Bridge ◽  
Parametric Modelling ◽  
Limit States ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Reinforced Concrete Bridge

The intelligent evaluation system of existing reinforced concrete bridge “BLP” is a special software for the load-bearing capacity rapid analysis and evaluation of the existing reinforced concrete bridge, which was developed by the Highway Research Institute of the Ministry of Transport. Based on the parametric modelling method, it can quickly and easily establish the finite element plane model of the bridge structure for the static analysis of ultimate bearing capacity limit states and serviceability limit state, under variety norms. And it can easily and quickly build variable-section beams and rebars, with the special module. According to the comprehensive modification method of the load-bearing capacity evaluation, it can automatically recommend checking sections, and automatically calculate partial modification coefficient of resistance effect, and conveniently judge the safety coefficient of the sections, and quickly get the results of bridge load-bearing capacity. In summary, this system can significantly improve the work efficiency and accuracy of load-bearing capacity for exiting reinforced concrete bridge. This paper introduces in detail the characteristics of the intelligent analysis technology, calculation principle and real bridge application examples of the system.

Simulation of Performance of CFST Elements Containing Differentiated Profile Tubes Filled with Reinforced Concrete

2019 ◽  
Vol 968 ◽  
pp. 281-287 ◽  
Author(s):  
Glib Vatulia ◽  
Alexey Lobiak ◽  
Vitaliy Chernogil ◽  
Mariia Novikova
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Accurate Method ◽  
Iteration Algorithm ◽  
Stress Strain ◽  
Load Bearing Capacity ◽  
Limiting State ◽  
Load Bearing ◽  
The Core

The approach to calculating CFST elements is considered in which physical non-linearity of materials, geometric non-linearity of the tube and the effect of increasing the strength of the core are taken into account. Finite element models are developed and proposed as the basis for more accurate method of calculating concrete-filled steel elements consisting of differentiated profile tubes filled with reinforced concrete. The technique uses a step iteration algorithm involving analytical dependencies and finite element simulation. The criterion for determining the load bearing capacity of CFST elements was the achievement of the stresses in the tube of the characteristic strength. The possibility of estimating the load bearing capacity of elements by limiting stresses in the core concrete is also implemented. The result of the calculations was obtaining the stress-strain and limiting state of the differentiated profile tubes with CFST elements, and graphic analysis of the regularities of stress redistribution at different stages of performance of columns. In general, with the accepted problem statement we could establish the exact stress-strain state, take into account the elastic-plastic deformations of concrete, its cracking and destruction, and geometric nonlinearity of the tube. The effect of performance of the corrugated sheet as a tube was established.

Experimental Study on Residual Load Bearing Capacity of SRC Eccentric Columns after Exposure to Fire

2010 ◽  
Vol 163-167 ◽  
pp. 2240-2246 ◽  
Author(s):  
Jun Hua Li ◽  
Yue Feng Tang ◽  
Ming Zhe Liu
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Ultimate Strength ◽  
Room Temperature ◽  
Ultimate Load ◽  
Flexural Rigidity ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Steel Reinforced Concrete

This paper provided three test data pertaining to the mechanical properties of steel reinforced concrete (SRC) eccentric columns after exposure to fire and one comparative test data pertaining to the mechanical properties of steel reinforced concrete columns at room temperature. The influence of eccentricity on failure mode, distortion performance and ultimate load bearing capacity are mainly studied. Test results show that the failure modes of steel reinforced concrete eccentric columns after exposure to fire are similar to that at room temperature. Strain along the section height at mid-span section of eccentric columns before loaded to 90% ultimate load bearing capacity is linearly distributed and well agree with the plane section supposition. After exposure to fire, the flexural rigidity and load bearing capacity of specimens are all declined compared with that at normal temperature. In various loading stages from the initial loading to 80% ultimate strength, the ratio of flexural rigidity of SRC eccentric columns after exposure to fire and at normal temperature is ranged from 0.30 to 0.59. With the same concrete strength and heating condition, the ultimate strength of specimens decreases with the increasing of eccentricity. The ultimate bearing capacity of all specimens at normal room temperature is calculated on the method proposed by Chinese regulation JGJ 138-2001. The compared results of experimental values and calculating values show that the residual load bearing capacity of SRC eccentric columns after exposure to fire is about 69% to 81% of that at room temperature.

Sign in / Sign up

Export Citation Format

Share Document