Structural analysis of high-rise reinforced concrete building structures during construction

Song, Xiaobin,Gu, Xianglin,Zhang, Weiping,Zhao, Tingshen,Jin, Xianyu Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.36 No.4

This paper presents a three-dimensional finite element method based structural analysis model for structural analysis of reinforced concrete high-rise buildings during construction. The model considered the time-dependency of the structural configuration and material properties as well as the effect of the construction rate and shoring stiffness. Uniaxial compression tests of young concrete within 28 days of age were conducted to establish the time-dependent compressive stress-strain relationship of concrete, which was then used as input parameters to the structural analysis model. In-situ tests of a RC high-rise building were conducted, the results of which were used for model verification. Good agreement between the test results and model predictions was achieved. At the end, a parametric study was conducted using the verified model. The results indicated that the floor position and construction rate had significant effect on the shore load, whereas the influence of the shore removal timing and shore stiffness have much smaller. It was also found that the floors are more prone to cracking during construction than is ultimate bending failure.

A curvature method for beam-column with different materials and arbitrary cross-section shapes

Xiaobin Song 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.43 No.2

This paper presents a curvature method for analysis of beam-columns with different materials and arbitrary cross-section shapes and subjected to combined biaxial moments and axial load. Both material and geometric nonlinearities (the p-delta effect in this case) were incorporated. The proposed method considers biaxial curvatures and uniform normal strains of discrete cross-sections of beamcolumns as basic unknowns, and seeks for a solution of the column deflection curve that satisfies force equilibrium conditions. A piecewise representation of the beam-column deflection curve is constructed based on the curvatures and angles of rotation of the segmented cross-sections. The resulting bending moments were evaluated based on the deformed column shape and the axial load. The moment curvature relationship and the beam-column deflection calculation are presented in matrix form and the Newton-Raphson method is employed to ensure fast and stable convergence. Comparison with results of analytic solutions and eccentric compression tests of wood beam-columns implies that this method is reliable and effective for beam-columns subjected to eccentric compression load, lateral bracings and complex boundary conditions.

ER-Fuzz:Conditional Code Removed Fuzzing

( Xiaobin Song ),( Zehui Wu ),( Yan Cao ),( Qiang Wei ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.7

Coverage-guided fuzzing is an efficient solution that has been widely used in software testing. By guiding fuzzers through the coverage information, seeds that generate new paths will be retained to continually increase the coverage. However, we observed that most samples follow the same few high-frequency paths. The seeds that exercise a high-frequency path are saved for the subsequent mutation process until the user terminates the test process, which directly affects the efficiency with which the low-frequency paths are tested. In this paper, we propose a fuzzing solution, ER-Fuzz, that truncates the recording of a high-frequency path to influence coverage. It utilizes a deep learning-based classifier to locate the high and low-frequency path transfer points; then, it instruments at the transfer position to promote the probability low-frequency transfer paths while eliminating subsequent variations of the high-frequency path seeds. We implemented a prototype of ER-Fuzz based on the popular fuzzer AFL and evaluated it on several applications. The experimental results show that ER-Fuzz improves the coverage of the original AFL method to different degrees. In terms of the number of crash discoveries, in the best case, ER-Fuzz found 115% more unique crashes than did AFL. In total, seven new bugs were found and new CVEs were assigned.

Structural analysis of high-rise reinforced concrete building structures during construction

Xiaobin Song,Xianglin Gu,Weiping Zhang,Tingshen Zhao,Xianyu Jin 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.36 No.4

This paper presents a three-dimensional finite element method based structural analysis model for structural analysis of reinforced concrete high-rise buildings during construction. The model considered the time-dependency of the structural configuration and material properties as well as the effect of the construction rate and shoring stiffness. Uniaxial compression tests of young concrete within 28 days of age were conducted to establish the time-dependent compressive stress-strain relationship of concrete,which was then used as input parameters to the structural analysis model. In-situ tests of a RC high-rise building were conducted, the results of which were used for model verification. Good agreement between the test results and model predictions was achieved. At the end, a parametric study was conducted using the verified model. The results indicated that the floor position and construction rate had significant effect on the shore load, whereas the influence of the shore removal timing and shore stiffness have much smaller. It was also found that the floors are more prone to cracking during construction than is ultimate bending failure.

A curvature method for beam-column with different materials and arbitrary cross-section shapes

Song, Xiaobin Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.43 No.2

This paper presents a curvature method for analysis of beam-columns with different materials and arbitrary cross-section shapes and subjected to combined biaxial moments and axial load. Both material and geometric nonlinearities (the p-delta effect in this case) were incorporated. The proposed method considers biaxial curvatures and uniform normal strains of discrete cross-sections of beam-columns as basic unknowns, and seeks for a solution of the column deflection curve that satisfies force equilibrium conditions. A piecewise representation of the beam-column deflection curve is constructed based on the curvatures and angles of rotation of the segmented cross-sections. The resulting bending moments were evaluated based on the deformed column shape and the axial load. The moment curvature relationship and the beam-column deflection calculation are presented in matrix form and the Newton-Raphson method is employed to ensure fast and stable convergence. Comparison with results of analytic solutions and eccentric compression tests of wood beam-columns implies that this method is reliable and effective for beam-columns subjected to eccentric compression load, lateral bracings and complex boundary conditions.

Generalizations of V-rings

Song, Xianmei,Yin, Xiaobin Department of Mathematics 2005 Kyungpook mathematical journal Vol.45 No.3

In this paper, we introduce a new notion which we call a generalized weakly ideal. We also investigate characterizations of strongly regular rings with the condition that every maximal left ideal is a generalized weakly ideal. It is proved that R is a strongly regular ring if and only if R is a left GP-V-ring whose every maximal left (right) ideal is a generalized weakly ideal. Furthermore, if R is a left SGPF ring, and every maximal left (right) ideal is a generalized weakly ideal, it is shown that R/J(R) is strongly regular. Several known results are improved and extended.

Refractory Performance of the Axial Tensile Welded Hollow Spherical Joint

Xiaobin Qiu,Bingsheng Huang,Haoyu Song,Zhen Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.6

To study the refractory performance of the axial tensile welded hollow spherical joint, the steady-state test of heating under constant load was carried out on the joint specimens with different load levels. The failure modes, temperature field, displacement-time curves, and refractory performance of the spherical joints exposed to fire are investigated and analyzed. The experimental results indicate that the failure modes of the joints exposed to fire are pull-out failures. The failure location is at the intersection of the steel tube-hollow sphere. The lowest temperature is located at the intersection of the steel tube-hollow sphere. The closer you get to the equator of the hollow sphere, the higher the spherical temperature. The smaller the load level, the higher the refractory temperature and the longer the refractory limit of the joints. The correctness of the numerical model was verified by comparison with the experimental result. Numerical simulations show that with the increase of the load levels, the refractory performance of the joints gradually decreases, and the downward trend gradually slows down. Compared to the refractory temperature code-recommended, the refractory temperature of the tensile joints is very conservative.

Study of Fire Resistance Performance of Stiffened Welded Hollow Spherical Joint Under Axial Tension

Xiaobin Qiu,Tao Chen,Bingsheng Huang,Jingrui Zhu,Zhen Zhang,Haoyu Song 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.2

To study the fire resistance performance of stiffened welded hollow spherical joints under axial tension, two specimens with load ratios of 0.4 and 0.6 were subjected. The temperature distribution, failure mode, and fire resistance performance of stiffened welded hollow spherical joints under axial tension were obtained. The test results show that the failure mode of the joint was a pull-out failure. During the heating process, the closer to the spherical equator, the higher the spherical temperature, and the temperature of the sphere at the stiffener is lower than that of the sphere at the non-stiffener. The load ratio has a great influence on the refractory performance of the stiffened welded hollow sphere joint. When the load ratio of the specimen is reduced from 0.60 to 0.40, the fire resistance time of the specimen increases by 4.47 min, and the critical temperature increases by 21.3 °C. According to the European Code, the finite element model for the stiffened welded hollow spherical joints is established. The effect law of various influencing factors on the fire resistance performance of stiffened welded hollow spherical joints is studied. The research results show that reducing the load ratio and increasing the thickness of the sphere can significantly improve the fire resistance performance of the joint. The calculation formula of the critical temperature of steel members in the current standard not suitable for the calculation of the critical temperature of the welded hollow spherical joint. The critical temperature values with different load ratios recommended by the current standard were relatively more conservative. Taking the ambient temperature as the fire resistance temperature, the finite element analysis results were fitted, and the formula for calculating the fire resistance temperature of the stiffened welded hollow spherical joint was proposed.

Heat-resistant Poly(methyl methacrylate) Modified by Biomass Syringaldehyde Derivative: Preparation, Thermostability and Transparency

Xiaobin Gao,Song Mei,Xueyong Yong,Danyu Zhao,Jinpeng Bao,Jianping Deng 한국섬유공학회 2019 Fibers and polymers Vol.20 No.11

Poly(methyl methacrylate) (PMMA) has found a lot of practical uses, however, how to efficiently and costeffectivelyimprove its relatively low thermal properties remains as an intractable academic challenge. This article reports anovel strategy for improving heat-resistance of PMMA by using biomass syringaldehyde. Syringaldehyde methacrylate(SMA) was first synthesized and then used as comonomer to copolymerize with methyl methacrylate (MMA) through bulkpolymerization and solution polymerization. The copolymers can be obtained in high yield and demonstrate remarkablyimproved heat-resistance according to differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) andderivative thermogravimetry analyses (DTG). Moreover, the modified PMMA still maintains good light transmittance invisible range. The study provides a new alternative for modifying PMMA, and the modified PMMA may find newapplications as heat-resistant polymeric material which cannot routinely achieved by PMMA itself. In addition, SMA as anew type of green heat-resistant modifier derived from renewable biomass syringaldehyde may have potential applications inheat-resistant modification of materials.

Synergetics based damage detection of frame structures using piezoceramic patches

Xiaobin Hong,Jiaobiao Ruan,Guixiong Liu,Tao Wang,Youyong Li,Gangbing Song 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.17 No.2

This paper investigates the Synergetics based Damage Detection Method (SDDM) for frame structures by using surface-bonded PZT (Lead Zirconate Titanate) patches. After analyzing the mechanism of pattern recognition from Synergetics, the operating framework with cooperation-competition-update process of SDDM was proposed. First, the dynamic identification equation of structural conditions was established and the adjoint vector (AV) set of original vector (OV) set was obtained by Generalized Inverse Matrix (GIM).Then, the order parameter equation and its evolution process were deduced through the strict mathematics ratiocination. Moreover, in order to complete online structural condition update feature, the iterative update algorithm was presented. Subsequently, the pathway in which SDDM was realized through the modified Synergetic Neural Network (SNN) was introduced and its assessment indices were confirmed. Finally, the experimental platform with a two-story frame structure was set up. The performances of the proposed methodology were tested for damage identifications by loosening various screw nuts group scenarios. The experiments were conducted in different damage degrees, the disturbance environment and the noisy environment, respectively. The results show the feasibility of SDDM using piezoceramic sensors and actuators, and demonstrate a strong ability of anti-disturbance and anti-noise in frame structure applications. This proposed approach can be extended to the similar structures for damage identification.