Quality Evaluation of Steel Plate Reinforced Concrete via Nondestructive Ultrasonic Wave Measurement After Standard Fire Condition

2011 ◽  
Vol 21 (1) ◽  
pp. 17-28
Author(s):  
Shih-Yi Kuo
Author(s):  
Huiyun Li ◽  
Guangyu Shi

The steel plate reinforced concrete (SC) walls and roofs are effective protective structures in nuclear power plants against aircraft attacks. The mechanical behavior of the concrete in SC panels is very complicated when SC panels are under the action of impacting loading. This paper presents a dynamic material model for concrete subjected to high-velocity impact, in which pressure hardening, strain rate effect, plastic damage, and tensile failure are taken into account. The loading surface of the concrete undergoing plastic deformation is defined based on the extended Drucker–Prager strength criterion and the Johnson–Cook material model. The associated plastic flow rule is utilized to evaluate plastic strains. Two damage parameters are introduced to characterize, respectively, the plastic damage and tensile failure of concrete. The proposed concrete model is implemented into the transient nonlinear dynamic analysis code ls-dyna. The reliability and accuracy of the present concrete material model are verified by the numerical simulations of standard compression and tension tests with different confining pressures and strain rates. The numerical simulation of the impact test of a 1/7.5-scale model of an aircraft penetrating into a half steel plate reinforced concrete (HSC) panel is carried out by using ls-dyna with the present concrete model. The resulting damage pattern of concrete slab and the predicted deformation of steel plate in the HSC panel are in good agreement with the experimental results. The numerical results illustrate that the proposed concrete model is capable of properly charactering the tensile damage and failure of concrete.


2015 ◽  
Vol 22 (5) ◽  
pp. 585-596 ◽  
Author(s):  
Damian BEBEN ◽  
Adam STRYCZEK

The paper presents a numerical analysis of corrugated steel plate (CSP) bridge with reinforced concrete (RC) relieving slab under static loads. Calculations were made based on the finite element method using Abaqus software. Two computation models were used; in the first one, RC slab was used, and the other was without it. The effect of RC slab to deformations of CSP shell was determined. Comparing the computational results from two numerical models, it can be concluded that when the relieving slab is applied, substantial reductions in displacements, stresses, bending mo­ments and axial thrusts are achieved. Relative reductions of displacements were in the range of 53–66%, and stresses of 73–82%. Maximum displacements and bending moments were obtained at the shell crown, and maximum stresses and axial thrusts at the quarter points. The calculation results were also compared to the values from experimental tests. The course of computed displacements and stresses is similar to those obtained from experimental tests, although the absolute values were generally higher than the measured ones. Results of numerical analyses can be useful for bridge engineering, with particular regard to bridges and culverts made from corrugated steel plates for the range of necessity of using additional relieving elements.


2006 ◽  
Vol 302-303 ◽  
pp. 138-149 ◽  
Author(s):  
Gai Fei Peng ◽  
Sammy Yin Nin Chan ◽  
Qi Ming Song ◽  
Quan Xin Yi

This paper presents a review on the effect of fire on concrete, citing 43 references. It was found that most of them are on the behavior of concrete under high temperature conditions more or less different from the standard fire condition. The problem of spalling, which high-strength concrete encounters when exposed to fire, is especially urgent to solve. Since the literature on the behavior of concrete under fire conditions is very limited, the literature even under elevated temperature has to be used as a part of the base of further research. The further research needs urgently to be carried out under the standard fire condition. Residual mechanical properties reported in most previous literature might be overestimated, where natural cooling was usually employed. Proper evaluation of fire resistance of concrete needs more experimental data obtained under various cooling regimes such as water spraying or water quenching.


2010 ◽  
Vol 163-167 ◽  
pp. 1445-1450
Author(s):  
Gui He Tang ◽  
Bo Wu

Using the computer program SAFIR, the behaviors of restrained reinforced concrete (RC) beams with slab exposed to ISO834 standard fire are analyzed. The influences of three parameters (i.e., width of slab, axial restraint stiffness ratio, and rotational restraint stiffness ratio) on the beams’ behaviors in fire are investigated. Simulation results show that: (a) the axial force in the slab is much larger than that in the beam on the whole; (b) after 0.5 hour of heating the axial force in the slab decreases gradually with an increasing of the slab width ranging from 1.0 m to 2.5 m, but the influence of the slab width ranging from 1.0 m to 2.5 m on the axial force in the beam is limited; and (c) the effect of the rotational restraint stiffness ratio on the axial force in the beam/slab is very limited, but the beam’s peak hogging moment increases gradually with an increasing of the rotational restraint stiffness ratio.


2018 ◽  
Vol 4 (4) ◽  
pp. 712 ◽  
Author(s):  
Abdelraouf Tawfik Kassem

Reinforced concrete slabs are elements in direct contact with superimposed loads, having high surface area and small thickness. Such a condition makes slabs highly vulnerable to fire conditions. Fire results in exaggerated deformations in reinforced concrete slabs, as a result of material deterioration and thermal induced stresses. The main objective of this paper is to deeply investigate how circular R.C. slabs, of different configurations, behave in fire condition. That objective has been achieved through finite element modelling. Thermal-structural finite element models have been prepared, using "Ansys". Finite element models used solid elements to model both thermal and structural slab behaviour. Structural loads had been applied, representing slab operational loads, then thermal loads were applied in accordance with ISO 843 fire curve. Outputs in the form of deflection profile and edge rotation have been extracted out of the models to present slab deformations. A parametric study has been conducted to figure out the significance of various parameters such as; slab depth, slenderness ratio, load ratio, and opening size; regarding slab deformations. It was found that deformational behaviour differs significantly for slabs of thickness equal or below 100 mm, than slabs of thickness equal or above 200 mm. On the other hand considerable changes in slabs behaviour take place after 30 minutes of fire exposure for slabs of thickness equals or below 100 mm, while such changes delay till 60 minutes for slabs of thickness equals or above 200 mm.


2018 ◽  
Vol 206 ◽  
pp. 01014
Author(s):  
Ahmed K. Taha ◽  
Zhengguo Gao ◽  
Dahai Huang

Aluminum foam is a lightweight material with high energy absorption capacity. In this study A Nonlinear three-dimensional hydrocode numerical simulation was carried out using autodyn-3d, which is an extensive code dealing with explosion problems. In this simulation, a high explosive material (comp B) is blasted against several concrete panels. The model was first validated using experimental tests carried out by Chengqing and has shown good results. Several numerical tests were carried out to study two parameters that affect the deflection of reinforced concrete panels. The parameters included are the thickness of concrete target and the thickness of steel plate. The results showed that increasing the thickness of the steel plate has an insignificant effect on the deflection of the reinforced concrete target while increasing the thickness of the concrete panel has a significant effect on the deflection of the concrete target.


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