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CONTENTS
Volume 41, Number 5, December10 2021
 


Abstract
This paper examines the fire performance of uninsulated and uncoated restrained steel-concrete composite beams supplemented with externally prestressed strands through advanced numerical simulation. In this work, a sequentially coupled thermo-mechanical analysis is carried out using ABAQUS. This analysis utilizes a highly nonlinear three-dimensional finite element (FE) model that is specifically developed and validated using full-sized specimens tested in a companion fire testing program. The developed FE model accounts for nonlinearities arising from geometric features and material properties, as well as complexities resulting from prestressing systems, fire conditions, and mechanical loadings. Four factors are of interest to this work including effect of restraints (axial vs. rotational), degree of stiffness of restraints, the configuration of external prestressed tendons, and magnitude of applied loading. The outcome of this analysis demonstrates how the prestressing force in the external tendons is primarily governed by the magnitude of applied loading and experienced temperature level. Interestingly, these results also show that the stiffness of axial restraints has a minor influence on the failure of restrained and prestressed steel-concrete composite beams. When the axial restraint ratio does not exceed 0.5, the critical deflection of the composite beam is lower than that of the composite beam with a restraint ratio of 1.0.

Key Words
axial and rotational restraints; finite element analysis; fire resistance; prestressed composite steel-concrete beams

Address
Huanting Zhou and Shaoyuan Li: School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430072, China
Chao Zhang: College of Civil Engineering, Tongji University, Shanghai 200092, China
M.Z. Naser: Glenn Department of Civil Engineering, Clemson University, South Carolina, USA

Abstract
Nowadays, one of the practical, fast and easy ways to strengthen steel elements is the use of Carbon Fiber Reinforced Polymer (CFRP). Most previous research in the CFRP strengthening of steel members has carried out on straight steel members. The main difference between horizontal curved beams and straight beams under vertical load is the presence of torsional moment in the horizontal curved beams. In the other words, the horizontal curved beams are analyzed and designed for simultaneous internal forces included bending moment, torsional moment, and shear force. The horizontal curved steel beams are usually used in buildings, bridges, trusses, and others. This study explored the effect of the CFRP strengthening on the behavior of the horizontal curved square hollow section (SHS) steel beams. Four specimens were analyzed, one non-strengthened curved steel beam as a control column and three horizontal curved steel beams strengthened using CFRP sheets (under concentrated load and uniform distributed load). To analyze the horizontal curved steel beams, three dimensional (3D) modeling and nonlinear static analysis methods using ANSYS software were applied. The results indicated that application of CFRP sheets in some specific locations of the horizontal curved steel beams could increase the ultimate capacity of these beams, significantly. Also, the results indicated when the horizontal curved steel beams were under distributed load, the increase rate in the ultimate capacity was more than in the case when these beams were under concentrated load.

Key Words
horizontal curved beams; numerical investigation; SHS steel; CFRP; strengthening; theoretical analysis

Address
Amir Hamzeh Keykha: Department of Civil Engineering, Zahedan Branch, Islamic Azad University, Zahedan, Iran

Abstract
This paper presents experimental and analytical studies to understand the behavior of crumb rubber concrete (CRC)-filled fiber reinforced polymer (FRP) and steel tube double skin column (DSC) and beam (DSB) members under cyclic loading. The main test variable was the percentage of rubber which ranged from 0 to 40%. For column members, different heights corresponding to different aspect ratios were examined to understand the to understand the effect of DSCs' slenderness on the cyclic response of the columns. the. The behavior of the specimens in terms of failure mode, strain development, energy dissipation, load-displacement response were presented and compared. The ability of the current provisions of the Australian codes to predict the capacity of such double skin members was also evaluated based on the test results. This study concluded that the reduction in the concrete strength was more severe at the material level compared to structural level. Also, as the load changed from axial compression in columns to pure moment in beams the negative effect of rubber percentage on the strength became less significant.

Key Words
crumb rubber concrete; cyclic compressive loading; double skin columns; flexural behavior; fibre reinforced polymer (FRP); Steel tube

Address
Danda Li, Reza Hassanli, Yue Su, Yan Zhuge and Xing Ma:University of South Australia, UniSA STEM, Mawson Lakes, SA 5095, Australia

Abstract
To elucidate the differences in the collapse behavior between a single-story beam-column assembly and multi-story frame, two 1/3-scale two-bay composite frames, including a single-story composite beam–column assembly and a three-story composite sub-frame, were designed and quasi-statically tested. The load–displacement responses, failure modes, and internal force development of the two frames were analyzed and compared in detail. Furthermore, the resistance mechanisms of the two specimens were explored, and the respective contributions of different load-resisting mechanisms to the total resistances were quantitatively separated to gain deeper insights. The experimental tests indicated that Vierendeel action was present in the two-dimensional multi-story frames, which led to an uneven internal force distribution among the three stories. The collapse resistance of TSDWA-3S in the flexural stage was not significantly increased by the structural redundancy provided by the additional story, as compared to that of TSDWA-1S. Although the development of the load response was similar in the two specimens at flexural stage, the collapse mechanisms of the multi-story composite frame were much more complicated than those of the single-story beam–column assembly, and the combined action between stories was critical in determining the internal force redistribution and rebalancing of the remaining structure.

Key Words
multi-story composite sub-frame; progressive collapse; single-story composite beam–column assembly; static test; performance analysis

Address
Wei-hui Zhong: School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China;
Key Laboratory of Structural Engineering and Earthquake Resistance, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
Zheng Tan, Li-min Tian, Bao Meng, Yu-hui Zheng and Shi-chao Daun:School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China

Abstract
Many existing transmission or communication towers designed several decades ago have undergone nonreversible performance degradation, making it hardly meet the additional requirements from upgrades in wind load design codes and extra services of electricity and communication. Therefore, a new-type non-destructive reinforcement method was proposed to reduce the on-site operation of drilling and welding for improving the quality and efficiency of reinforcement. Six built-up steel angle members were tested under compression to examine the reinforcement performance. Subsequently, the cyclic loading test was conducted on a pair of steel angle tower sub-structures to investigate the reinforcement effect, and a simplified prediction method was finally established for calculating the buckling bearing capacity of those new-type retrofitted built-up steel angles. The results indicates that: no apparent difference exists in the initial stiffness for the built-up specimens compared to the unreinforced steel angles; retrofitting the steel angles by single-bolt clamps can guarantee a relatively reasonable reinforcement effect and is suggested for the reduced additional weight and higher construction efficiency; for the substructure test, the latticed substructure retrofitted by the proposed reinforcement method significantly improves the lateral stiffness, the non-deformability and energy dissipation capacity; moreover, an apparent pinching behavior exists in the hysteretic loops, and there is no obvious yield plateau in the skeleton curves; finally, the accuracy validation result indicates that the proposed theoretical model achieves a reasonable agreement with the test results. Accordingly, this study can provide valuable references for the design and application of the non-destructive upgrading project of steel angle towers.

Key Words
built-up steel angle; non-destructive reinforcement; overall bending capacity; reinforcement behavior; substructure tower test

Address
Jian-Tao Wang: Department of Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, P.R. China
Department of Civil Engineering, Tsinghua University, Beijing 100084, P.R. China
Xiao-Hong Wu: School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, P.R. China
Bin Yang and Qing Sun: Department of Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, P.R. China

Abstract
In this work, a simple quasi 3-D parabolic shear deformation theory is developed to examine the bending response of antisymmetric cross-ply laminated composite plates under different types of mechanical loading. The main feature of this theory is that, in addition to including the transverse shear deformation and thickness stretching effects, it has only five-unknown variables in the displacement field modeling like Mindlin's theory (FSDT), yet satisfies the zero shear stress conditions on the top and bottom surfaces of the plate without requiring a shear correction factor. The static version of principle of virtual work was employed to derive the governing equations, while the bending problem for simply supported antisymmetric cross-ply laminated plates was solved by a Navier-type closed-form solution procedure. The adequacy of the proposed model is handled by considering the impact of side-to-thickness ratio on bending response of plate through several illustrative examples. Comparison of the obtained numerical results with the other shear deformation theories leads to the conclusion that the present model is more accurate and efficient in predicting the displacements and stresses of laminated composite plates.

Key Words
bending response; cross-ply laminated plates; quasi 3-D; thickness stretching

Address
Kada Draiche: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria;
Department of Civil Engineering, University of Tiaret, BP 78 Zaaroura, 14000 Tiaret, Algeria
Mahmoud M. Selim: Department of Mathematics, Al-Aflaj College of Science and Humanities, Prince Sattam bin Abdulaziz University,
Al-Aflaj 710-11912 Saudi Arabia
Abdelmoumen Anis Bousahla: Laboratoire de Modélisation et Simulation Multi-échelle, Université de Sidi Bel Abbés, Algeria
Abdelouahed Tounsi: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria;
YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea;
Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals,
31261 Dhahran, Eastern Province, Saudi Arabia;
Interdisciplinary Research Center for Construction and Building Materials, KFUPM, Dhahran, Saudi Arabia
Fouad Bourada: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria;
Département des Sciences et de la Technologie, université de Tissemsilt, BP 38004 Ben Hamouda, Algérie
Abdeldjebbar Tounsi: Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria
S.R. Mahmoud: GRC Department, Jeddah Community College, King Abdulaziz University, Jeddah, Saudi Arabia

Abstract
The seismic performance of rigid steel frames is widely investigated, but that of semi-rigid (SR) steel frames are not studied extensively, especially for near-field earthquakes. In this paper, the performances of five and ten-story steel SR frames having different degrees of semi-rigidity are evaluated at four performance points in the four different deformation states, namely, the elastic, elasto-plastic, plastic, and near collapse states. The performances of the SR frames are measured by the response parameters including the maximum values of the top floor displacement, base shear, inter-story drift ratio, number of plastic hinges, and SRSS of plastic hinge rotations. These response parameters are obtained by the capacity spectrum method (CSM) using pushover analysis. The validity of the response parameters determined by the CSM is evaluated by the results of the nonlinear time history analysis (NLTHA) for both near and far-field earthquakes at different PGA levels, which are consistent with the performance points. Results of the study show that the plastic hinges of SR frame significantly increase in the range of plastic to near-collapse states for both near and far-field earthquakes. The effect of the degree of semi-rigidity is pronounced only at higher degrees of semi-rigidity. The predictions of the CSM are fairly well in comparison to the NLTHA.

Key Words
CSM; far-field; near-field; NLTHA; performance points; semi-rigid

Address
Vijay Sharma: Department of Applied Mechanics, Government Engineering College, Palanpur 385001, India
Mahendra K. Shrimali, Shiv D. Bharti and Tushar K. Datta: National Centre for Disaster Mitigation and Management, Malaviya National Institute of Technology Jaipur, JLN Marg Jaipur, 302017, India

Abstract
The purpose of this paper is to investigate the axial bearing capacity and residual properties of steel reinforced recycled aggregate concrete (SRC) column after elevated temperature. A total of 48 SRC columns were designed for the static loading test after elevated temperature. The variables include replacement ratios, designed temperature, target duration, thicknesses of cover concrete, steel ratios and stirrup spacing. From this test, the mass loss ratio and stress load-deformation curve were obtained, and the influence of various parameters on residual bearing capacity were analyzed. ABAQUS was used to calculate the temperature field of specimens, and then got temperature damage distribution on the cross-section concrete. It was shown that increasing of the elevated temperatures leaded to the change of concrete color from smoky-gray to grayish brown and results in reducing the bearing capacity of SRC columns. The axial damage and mechanism of SRC columns were similar to those of reinforced natural aggregate concrete columns at the same temperatures. Finally, the calculation method of axial compressive residual bearing capacity of SRC columns recycled concrete columns after high temperature was reported based on the test results and finite element analysis.

Key Words
axial compression; bearing capacity; fire test; static test; structural steel reinforced recycled concrete column

Address
Zongping Chen: College of Civil Engineering and Architecture, Guangxi University, 100# east daxue road, Nanning, 530004, China;
Key Laboratory of Disaster Prevention and Structure Safety of Chinese Ministry of Education,Guangxi University,
100# east daxue road,Nanning, 530004,China
Yuhan Liang, Linlin Mo and Maogen Ban: College of Civil Engineering and Architecture, Guangxi University, 100# east daxue road, Nanning, 530004, China

Abstract
Built-up Double-I (BD-I) columns have been commonly used for mid-rise steel-frame structures in Iran. These columns consist of two hot rolled IPE sections which are connected by two cover plates and fillet welds. Until 2017, BD-I columns were employed in intermediate moment resisting frames (MRF) using welded flange plate (WFP) connections. To evaluate the seismic behavior of the connections, four samples were made and tested based on cyclic loading according to AISC 341-16. It was concluded that typical samples cannot satisfy the seismic provisions related to intermediate MRFs. In contrast, the proposed connections retrofitted with two-part external diaphragms were able to satisfy not only the seismic requirements related to intermediate MRFs but also those related to special MRFs according to AISC. The numerical modeling of these samples was performed using ABAQUS finite element software. This study compared the hysteresis moment-rotation curves, plastic strains, and behavior modes in both experimental samples and numerical models.

Key Words
built-up double-I column; cyclic load; external diaphragm; steel moment resisting frame; WFP connection

Address
Amir Tabebordbar and Farshid Fathi: Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
Seyed Mehdi Dehghan and Mohammad Amir Najafgholipour: Department of Civil and Environmental Engineering, Shiraz University of Technology, Shiraz, Iran

Abstract
This study presents a 3D non-linear finite element (FE) assessment of dynamic soil-structure interaction (SSI). The numerical investigation has been performed on the time domain through a Finite Element (FE) system, while considering the nonlinear behavior of soil and the multi-directional nature of genuine seismic events. Later, the FE outcomes are analyzed to the recorded in-situ free-field and structural movements, emphasizing the numerical model's great result in duplicating the observed response. In this work, the soil response is simulated using an isotropic hardening elastic-plastic hysteretic model utilizing HSsmall. It is feasible to define the non-linear cycle response from small to large strain amplitudes through this model as well as for the shift in beginning stiffness with depth that happens during cyclic loading. One of the most difficult and unexpected tasks in resolving soil-structure interaction concerns is picking an appropriate ground motion predicted across an earthquake or assessing the geometrical abnormalities in the soil waves. Furthermore, an artificial neural network (ANN) has been utilized to properly forecast the non-linear behavior of soil and its multi-directional character, which demonstrated the accuracy of the ANN based on the RMSE and R2 values. The total result of this research demonstrates that complicated dynamic soil-structure interaction processes may be addressed directly by passing the significant simplifications of well-established substructure techniques.

Key Words
3D dimension; ANN; soil–interaction; time domain

Address
Bin Han: School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China

J.B. Sun:School of Design and the Built Environment, Curtin University, Perth, WA 6102, Australia

Milad Heidarzadeh: Department of Civil Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran

M.M. Nemati Jam: Department of Civil Engineering, K.N. Toosi University of Technology, Tehran, Iran

O. Benjeddou: Prince Sattam bin Abdulaziz University, College of Engineering, Department of Civil Engineering, Saudi Arabia, Alkharj, 16273


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