Nonlinear Structural Analysis of Fire-Exposed Reinforced Concrete Column

2015 ◽  
Vol 1095 ◽  
pp. 267-275
Author(s):  
Li Xian Liu ◽  
Long Lv ◽  
Yan Feng Zhao
Keyword(s):  
Reinforced Concrete ◽  
Structural Analysis ◽  
Computer Program ◽  
Fire Resistance ◽  
Mechanical Response ◽  
Concrete Strength ◽  
Reinforced Concrete Column ◽  
Rc Columns ◽  
Nonlinear Structural Analysis ◽  
Nonlinear Structural

A nonlinear structural analysis is presented for reinforced concrete (RC) columns exposed to fire. The analysis includes two steps: the first step is the calculation of the temperature distribution in concrete members, and the second the determination of the mechanical response due to elevated temperature and applied loading. In the thermal analysis, the effect of moisture is taken into account. The use of the computer program for evaluating the response of a RC column from the initial preloading stage to collapse, due to fire, is illustrated. The validity of the numerical model used in the program is verified by comparing the predictions from the computer program with measured results from full-scale fire resistance tests. The computer program can be used to predict the fire resistance of RC columns for any values of the significant parameters, such as load level, section dimensions, column length, concrete strength, concrete cover, aggregate type and reinforcement ratio.

scholarly journals NON-LINEAR ANALYSIS OF HOLLOW REINFORCED CONCRETE COLUMN QUARE CROSS-SECTION WITH VARIOUS LOAD ECCENTRICITY AND CONCRETE STRENGTH

2018 ◽  
Vol 5 (1) ◽  
pp. 33 ◽  
Author(s):  
Pingkan Nuryanti ◽  
Djoko Sulityo ◽  
Bambang Suhendro
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Graduate Program ◽  
Concrete Strength ◽  
Concrete Column ◽  
Reinforced Concrete Column ◽  
Rc Columns ◽  
Modes Of Failure ◽  
Cross Sectional Dimension ◽  
Non Linear

Hollow due to plumbing system has an effect to the building's visual and the aesthetic quality in terms of architecture. To overcome this, the pipe is planted in a construction structure such as a column. However, this will affect on the strength degradation and modes of failure of structural elements such as a column. The objective of this research is to study the strength, stiffness, ductility, cracking patterns, and modes of failure of hollow RC columns with square cross-section with various load eccentricity and concrete strength. In this research, 13 reinforced concrete columns with square cross section were made. Two of them were massive columns (C1E1, C1E2) with cross-sectional dimension of 150 x 150 mm2 and 800 mm long, six of them were hollow with the same size (C2E1, C3E1, C4E1, C2E2, C3E2, C4E2). Concrete strength fc'=34.52 MPa with eccentricity=60mm  and fc'=35.72 MPa with eccentricity 100 mm. Models were analyzed by nonlinear finite element method using ATENA v.2.1.10 software. The FE model is calibrated against recent experimental results from Zacoeb (2003). Once validated, the model is used to examine stiffness, ductility, cracking patterns, and modes of failure of hollow RC columns with a square cross-section with various load eccentricity. The numerical results show that the different ultimate load strength of C1E1, C2E1, C3E1, C4E1, C1E2, C2E2, C3E2, C4E2 are  0,32%, 2,22%, 1,61%, 7,74%, 1,25%, 0,65%, 2,63%, 1,94%, while the differents stiffnes are 18,30%, 21,30%, 23,79%, 31,57%, 15,22%, 22,67%, 21,39%, 14,41%, and the differents ductility are 48,71%, 33,64%, 3,39%, 41,04%, 52,30%, 22,99%, 18,11%, 7,76%. Crack pattern occurred in C1E1, C2E1, C3E1, C4E1, C1E2, C2E2, C3E2, C4E2 are flexural crack and shear cracks. Exhibit modes of failure of C1E1, C2E1, C3E1, C4E1 are compression failure and C1E2, C2E2, C3E2, C4E2 are tension failure.Keywords: ATENA, columns, eccentricity, failure, hollow, nonlinearANALISIS NON-LINEAR KOLOM BETON BERTULANG PENAMPANG SEGIEMPAT BERONGGA DENGAN VARIASI EKSENTRISITAS BEBAN DAN MUTU BETONLubang akibat pemasangan pipa pada konstruksi untuk keperluan instalasi (air hujan, sanitasi, listrik dan lain-lain) dapat berpengaruh pada visualitas bangunan dan akan mempengaruhi kualitas estetika dari segi arsitektur. Untuk mengatasi hal tersebut pipa ditanam didalam struktur konstruksi seperti kolom. Akan tetapi hal ini akan  menyebabkan  degradasi kekuatan beton dan  pola keruntuhan struktur pada kolom. Selain secara eksperimental, penelitian  ini dapat juga dilakukan secara numeris menggunakan  metode elemen hingga nonlinier. Penelitian ini bertujuan untuk mengetahui kekuatan, kekakuan, daktilitas, pola retak dan model keruntuhan kolom beton bertulang penampang persegi berongga dengan variasi eksentrisitas beban dan variasi mutu beton. Dalam penelitian ini dimodelkan 8 jenis kolom beton bertulang penampang segiempat yang terdiri dari 2 kolom masif (C1E1 dan C1E2) dan 6 kolom berongga (C2E1, C3E1, C4E1, C2E2, C3E2, C4E2) dengan ukuran 150 x 150 mm2, panjang 800 mm. Mutu beton fc'=34.52 MPa dengan eksentrisitas =60mm dan mtu beton fc'=35.72 MPa dengan eksentrisitas =100mm. Kolom dianalisis menggunakan software elemen hingga nonlinier ATENA V.2.1.10 dan hasilnya dibandingkan dengan hasil eksperimen sebelumnya  dari Zacoeb (2003). Setelah  model divalidasi, dilakukan perhitungan kekakuan, daktilitas, pengamatan pola retak dan jenis keruntuhan yang terjadi pada kolom penampang segiempat berongga dengan variasi eksentrisitas beban . Hasil penelitian menunjukkan bahwa kolom beton bertulang  berongga yang dimodelkan dengan ATENA yaitu untuk model kolom validasi C1E1, C2E1, C3E1, C4E1, C1E2, C2E2, C3E2, C4E2 mempunyai perbedaan beban maksimum dengan hasil eksperimen secara berturut-turut sebesar 0,32%, 2,22%, 1,61%, 7,74%, 1,25%, 0,65%, 2,63% dan 1,94%, dengan perbedaan kekakuan secara berturut-turut sebesar 18,30%, 21,30%, 23,79%, 31,57%, 15,22%, 22,67%, 21,39% dan 14,41%, dan perbedaan daktilitas  secara berturut-turut sebesar 48,71%, 33,64%, 3,39%, 41,04%, 52,30%, 22,99%, 18,11% dan 7,76%. Pola retak yang terjadi adalah pola retak lentur dan retak geser.  Pola keruntuhan pada C1E1, C2E1, C3E1, C4E1 merupakan keruntuhan tekan, sedangkan C1E2, C2E2, C3E2, C4E2  merupakan keruntuhan tarik.Kata-Kata kunci: ATENA, berlubang, eksentrisitas, keruntuhan, kolom, nonlinear.REFERENCESCervenka et al. (2007). Superior Material Models for Numerical Simulation of Concrete Cracking under Severe Conditions. Cervenka Consulting. Czech Republic.Public Work Ministry. (2007). SNI 03-2847-2007, Tata Cara Perhitungan Struktur Beton Bertulang untuk Bangunan Gedung. Bandung.Poston et al. (1985). Numerical Models for Non-prismatic Solid Cross-Section Behavior and Rectangular Cross-Section on Biaxially-Bred ColumnsSuprabowo, S. (1996). Analysis of Reinforced Concrete Column Capacity Perforated. Thesis. Department of Civil Engineering, Gadjah Mada University. Yogyakarta.Supriyadi. (1997). The Effect of Holes on Strongly Reinforced Concrete Column Boundaries. Thesis. Graduate Program. Gadjah Mada University. Yogyakarta.Zacoeb. A. (2003). Flexural Capacity of Reinforced Concrete Short Column with Variations Hole, Thesis. Graduate Program. Gadjah Mada University. Yogyakarta.

scholarly journals Analysis of Fire Resistance of Square-Cased Square Steel Tube Reinforced Concrete (ST-RC) Columns

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5541
Author(s):  
Gaoxiong Wang ◽  
Yanhong Bao ◽  
Li Yang ◽  
Yang Yu
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Load Ratio ◽  
Internal Force ◽  
Steel Tube ◽  
Fe Model ◽  
Cross Sectional ◽  
Rc Columns

Based on the finite element (FE) analysis software Abaqus, an FE model of square-cased square steel tube reinforced concrete (ST-RC) columns under the hybridized action of high-temperature and load is established. The accuracy of the FE model is verified using experimental data from existing studies. This model is used to analyze the temperature change, internal force distribution, and failure characteristics of the square-cased square ST-RC columns under the action of fire, as well as the factors affecting the fire resistance limit of the column. The results of FE analysis show that under the action of fire, the maximum internal temperature of the square-cased square ST-RC columns occurs in the corner of the section. Moreover, the stress and strain reach their maximum values at the concrete corner outside the tube. During the heating process, an internal force redistribution occurs in the square-cased square ST-RC column. At the same time, the proportion of the axial force and the bending moment of the reinforced concrete outside the pipe decreases gradually, while the proportion of the internal force of the core concrete-filled steel tube (CFST) increases gradually. In essence, it is a process of load transfer from the high-temperature to the low-temperature zone. In addition, the section size, load ratio, slenderness ratio, cross-sectional core area ratio, steel content, and external concrete strength are the main parameters affecting the fire resistance limit of the square-cased square ST-RC columns. Among them, the cross-sectional core area ratio, section size, steel ratio, and external concrete strength are positively correlated with the fire resistance limit of the composite column. On the contrary, with the increase in the load ratio and the slenderness ratio, the fire resistance limit of the square-cased square ST-RC columns decreases. On this basis, a simplified formula to calculate the fire resistance limit of square-cased square ST-RC columns is proposed. The research results can be used as a theoretical reference for the fire protection design of this kind of structure in practical engineering.

Short reinforced concrete column capacity under biaxial bending and axial load

2000 ◽  
Vol 27 (6) ◽  
pp. 1173-1182 ◽  
Author(s):  
H P Hong
Keyword(s):  
Reinforced Concrete ◽  
Probabilistic Analysis ◽  
Axial Load ◽  
Failure Surface ◽  
Biaxial Bending ◽  
Reinforced Concrete Column ◽  
Rc Columns ◽  
Nonlinear Stress ◽  
Modeling Errors ◽  
Error Optimization

The paper describes the development of a simple theoretical approach in estimating the capacity of short reinforced concrete (RC) columns under biaxial bending and axial load. The developed approach considers the nonlinear stress-strain relations of concrete and reinforcing steel and does not make the assumption about the limiting strain of extreme compression fiber of concrete. The solution is obtained using a nonlinearly constrained optimization algorithm. The approach was used to estimate the theoretical capacities of many tested RC columns found in the literature. A probabilistic analysis of the modeling errors was carried out using the ratios of the test-to-predicted results. The probabilistic analysis was extended to include two simplified theoretical methods: the reciprocal load method given by Bresler and the failure surface method given by Hsu.Key words: biaxial bending, modeling error, optimization, probability distribution.

scholarly journals Parallel in Time Algorithms for Nonlinear Iterative Methods

2018 ◽  
Vol 63 ◽  
pp. 248-257 ◽  
Author(s):  
Mustafa Gaja ◽  
Olga Gorynina
Keyword(s):  
Boundary Condition ◽  
Structural Analysis ◽  
Iterative Methods ◽  
Numerical Experiments ◽  
Numerical Results ◽  
Contact Boundary ◽  
Nonlinear Structural Analysis ◽  
Nonlinear Structural

In this paper we investigate the feasibility of applying the Parareal algorithm [5, 6] for quasi-static nonlinear structural analysis problems. We describe how this proposal has been realized and present some preliminary numerical results of applying this algorithm to a beam undergoing nonlinear deflection with a contact boundary condition. Further numerical experiments are needed to provide an evidence for the effciency of the method.

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