Seismic Response considering LSI for Steel Rectangular Water Purification Structures

Xuansheng Cheng,Bingbing Luo,Jia Chen 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11

In this paper, the finite element method (FEM) is used to analyze the dynamic response of steel rectangular water purification structure (SRWPS) considering liquid-solid interaction (LSI) in the water treatment project of the Zhuanglang Water Supply Company in Zhuanglang County. The near-field non-pulse Friuli wave, the near-field pulse Chi-Chi wave, the far-field long-period TOM wave and the Lanzhou wave are inputted along the x-direction of SRWPS, and LSI dynamics of the structure are studied under different earthquakes. The displacement, stress and liquid sloshing laws of SRWPS are obtained. SRWPS exhibits different displacement and stress responses under the action of four different seismic waves. The liquid sloshing wave height is only sensitive to long-field long-period waves. However, the structural deformation and liquid sloshing wave height are more sensitive to the Lanzhou wave. The structural deformation nephogram shows that the structural deformation of SRWPS is located in the middle of the non-hole partition, and the deformation between the open partition and the wallboard is small.

Seismic vulnerability of sliding isolation concrete rectangular liquid storage tanks

Xuansheng Cheng,Siyuan Yin,Wenjun Chen,Wei Jing 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.84 No.4

Based on the sliding isolation concrete LSS (liquid-storage structure), the specific seismic vulnerability is analyzed according to the general failure mode. In this study, 12 seismic inputs with different characteristics are used, and their acceleration peak values are modulated. By inputting these waves to the sliding isolation concrete storage structure, the finiteelement models of different concrete rectangular LSSs are obtained and analyzed, and the failure probabilities are obtained according to the IDA (incremental dynamic analysis) curves of the structure. The results show that when the seismic acceleration peak value gradually increases from 0.1 g to 1.0 g, the failure probability of LSS gradually increases with the increase in friction coefficient. However, the failure probability of a sliding isolation LSS is less than 100% and far less than the failure probability of a non-isolated rectangular LSS, which shows that an isolated liquid storage structure continues working under a big earthquake. Thus, the sliding isolation for the concrete LSS has a significant damping effect.

Calculation models and stability of composite foundation treated with compaction piles

Cheng, Xuansheng,Jing, Wei Techno-Press 2017 Geomechanics & engineering Vol.13 No.6

Composite foundation treated with compaction piles can eliminate collapsibility and improve the bearing capacity of foundation in loess area. However, the large number of piles in the composite foundation leads to difficulties in the analysis of such type of engineering works. This paper proposes two simplified methods to quantify the stability of composite foundation treated with a large number of compaction piles. The first method is based on the principle of making the area replacement ratios of the simplified model as the same time as the practical engineering situation. Then, discrete piles arranged in a triangular shape can be simplified in the model where the annular piles and compacted soil are arranged alternately. The second method implements equivalent continuous treatment in the pile-soil area and makes the whole treated region equivalent to a type of composite material. Both methods have been verified using treated foundation of an oil storage tank. The results have shown that the differences in the settlement values obtained from the water filled test in the field and those calculated by the two simplified methods are negligible. Using stability analysis, the difference ratios of the static and dynamic safety factors of the composite foundation treated with compaction piles calculated by these two simplified methods are found to be 3.56% and 5.32%, respectively. At the same time, both static and dynamic safety factors are larger than the general safety factor, which should be greater than or equal to 2.0 according to the provisions in civil engineering. This indicates that after being treated with compaction piles, the bearing capacity of the composite foundation is effectively improved and the foundation has enough safety reserve.

Vibration characteristic of rubber isolation plate-shell integrated concrete liquid-storage structure

Xuansheng Cheng,Lei Qi,Shanglong Zhang,Yiting Mu,Lingyu Xia 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.6

To obtain the seismic response of lead-cored rubber, shape memory alloy (SMA)-rubber isolation Plate-shell Integrated Concrete Liquid-Storage Structure (PSICLSS), based on a PSICLSS in a water treatment plant, built a scale experimental model, and a shaking table test was conducted. Discussed the seismic responses of rubber isolation, SMA-rubber isolation PSICLSS. Combined with numerical model analysis, the vibration characteristics of rubber isolation PSICLSS are studied. The results showed that the acceleration, liquid sloshing height, hydrodynamic pressure of rubber and SMA-rubber isolation PSICLSS are amplified when the frequency of seismic excitation is close to the main frequency of the isolation PSICLSS. The earthquake causes a significant leakage of liquid, at the same time, the external liquid sloshing height is significantly higher than internal liquid sloshing height. Numerical analysis showed that the low-frequency acceleration excitation causes a more significant dynamic response of PSICLSS. The sinusoidal excitation with first-order sloshing frequency of internal liquid causes a more significant sloshing height of the internal liquid, but has little effect on the structural principal stresses. The sinusoidal excitation with first-order sloshing frequency of external liquid causes the most enormous structural principal stress, and a more significant external liquid sloshing height. In particular, the principal stress of PSICLSSS with long isolation period will be significantly enlarged. Therefore, the stiffness of the isolation layer should be properly adjusted in the design of rubber and SMA-rubber isolation PSICLSS.

Reduced Sloshing Effect in Steel Tanks

Xuansheng Cheng,Jia Chen,Bingbing Luo 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.5

How to eff ectively reduce the sloshing wave height of the liquid is an important direction for the optimal design of the steel liquid storage structure. To fi nd the optimal design for structure with reduce liquid sloshing, the liquid–solid coupling seismic responses of steel rectangular water purifi cation structure (SRWPS) under diff erent opening arrangements in a partition are studied. Based on the fi nite element method, the arrangements of the No. 11 partition with 2, 4 and 6 holes are selected as the parameters to study how the variation of liquid sloshing wave height, the wall displacement and the stress change with the number of holes in the partition. The results show that the liquid sloshing height is signifi cantly reduced and the deformation of the wall of SRWPS is small when the partition plate with holes compared to non-perforated partitions. With the increase of holes in the No. 11 partition, the magnitude of the principal stress shows an increasing trend. This means that the tensile strength of the partition itself needs to be focused on when designing the openings of a partition to avoid tensile damage to the partition. However, when the number of partition openings is controlled in a certain range, the overall strength of the structure is less aff ected due to the synergy of functional partition and perforated baffl es. The 4-hole layout scheme of the No. 11 partition is the best solution to reduce liquid sloshing, as determined by comparing the liquid sloshing wave height, the wall deformation, the stress state and the partition displacement of SRWPS under diff erent opening schemes. The hole layout scheme proposed by this paper provides a new perspective for the SRWPS reducing sloshing analysis.

Pounding Dynamic Responses and Mitigation Measures of Sliding Base-isolated Concrete Rectangular Liquid Storage Structuress

Xuansheng Cheng,Wei Jing,Lei Qi,Lijun Gong 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7

This paper adopts a simplified spring-mass mechanical model for a concrete rectangular liquid-storage structure (CRLSS). Using a nonlinear model to simulate the pounding effect based on the contact element method, the effects of pounding and parameters on the dynamic responses of a CRLSS are studied. Mitigation measures for the pounding effect are investigated. The dynamic responses and the liquid sloshing height are increased after pounding. A parameter analysis shows that impact stiffness, initial gap, peak ground velocity, isolation period, liquid height and length-width ratio (LWR) of the structure are the main factors affecting the pounding response. Certain intermediate gaps can maximize the amplification caused by pounding. The coefficient of restitution (COR) can be reduced by installing a bumper layer, and the COR decreases with an increasing bumper thickness. A reasonable bumper design not only allows the moat wall to limit the displacement but also effectively reduces the structure’s dynamic responses and number of collisions caused by pounding.

Nonlinear Dynamic Responses of Sliding Isolation Concrete Liquid Storage Tank with Limiting-Devices

Xuansheng Cheng,Wei Jing,Huan Feng 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7

Based on potential flow theory (PFT), the lower limit for large amplitude liquid sloshing of rectangular liquid storage tank (RLST) is obtained, and a 3-D numerical model of sliding isolation concrete rectangular liquid storage tank (CRLST) with displacement limiting-devices is established. Results calculated by two-way coupling method are compared with those obtained by finite element method (FEM) based on nonlinear PFT, dynamic responses of isolation and no-isolation CRLSTs are compared, and parameter analysis is conducted. Results show that sliding isolation has a good damping effect on the dynamic responses. The more the dimension of seismic action is, the greater the dynamic responses will be; Dynamic responses increase with the increase of liquid level height; The nonlinear liquid sloshing becomes more pronounced as the PGA increases, but the effect of PGA on tensile stress of the structure is not significant after sliding isolation being taken; the resonance problem caused by excitation frequency should be paid enough attention to.

Seismic reliability of concrete rectangular liquid storage structures

Xuansheng Cheng,Peicun He,Dongjiang Yu 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.70 No.5

To analyze the seismic reliability of concrete rectangular liquid storage structures (CRLSSs), assuming that the wall thickness and internal liquid depth of CRLSSs are random variables, calculation models of CRLSSs are established by using the Monte Carlo finite element method (FEM). The principal stresses of the over-ground and buried CRLSSs are calculated under three rare fortification intensities, and the failure probabilities of CRLSSs are obtained. The results show that the seismic reliability increases with the increase of wall thickness, whereas it decreases with the increase of liquid depth. Between the two random factors, the seismic reliability of CRLSSs is more sensitive to the change in wall thickness. Compared with the over-ground CRLSS, the buried CRLSS has better reliability.

Flexural Performance of Prestressed Beams with Grouting Material of Various Compactnesses

Xuansheng Cheng,Haibo Liu,Jiaxuan Su,Liang Ma,Guoliang Li 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.8

Presently, there is no reliable conclusion on the effect of grouting compactness on the mechanical behavior of a prestressed concrete structure. To study the influence of grouting compactness on the performance of prestressed concrete, the flexural behaviors of 8 prestressed beams fabricated by using different sheaths materials with grouting material of various compactnesses were studied experimentally, and the flexural bearing capacity and flexural stiffness of the prestressed beams were discussed. The results showed that the variation in the average strain along the beam height has a linear distribution. The load-deflection curves included two turning points, which indicate concrete cracking and steel yielding. The effect of grouting compactnesses on the early stage of beam cracking is small, but the effect becomes increasingly obvious after beam cracking. The distribution of cracks in the prestressed beams with fuller grouting is more concentrated compared to that of beams with lower grouting compactness; when the crack spacing is smaller, the beam ductility is reduced, and the bearing capacity is improved. The fracture resistance and overall bearing capacity of metal sheaths prestressed concrete beams are better than those of plastic sheaths prestressed concrete beams. However, the ductility of prestressed beams with plastic sheaths is better than that of prestressed beams with metal sheaths. A reference is provided for such prestressed concrete beams, but in practical engineering, the relevant parameters should be reevaluated because the number of studied samples is limited.

Flexural performance test of a prestressed concrete beam with plastic bellows

Xuansheng Cheng,Junliang Hong,Liang Ma,Guoliang Li 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.2

The flexural performance of 8 types of prestressed concrete beams with plastic bellows under different grouting compactness is examined in this paper. By applying concentrated load and symmetrical load to 8 types of prestressed concrete test beams with plastic bellows, the flexural performance test of each test beam is carried out, and the mechanical characteristics and failure morphology of each test beam under different grouting compactness are discussed. The influence of duct grouting compactness on the strain of steel bars and concrete, mid-span deflection and stiffness of prestressed concrete beam are analyzed. The results show that the cracking load and ultimate load of the test beam increases constantly with the increase of the duct grouting compactness, and the flexural bearing capacity of prestressed concrete beams has also been significantly improved. After the concrete is cracked, the mid-span deflection of the prestressed concrete beam gradually decreases with the increase of the duct grouting compactness under the same load form and load grade. At the same load grade, the mid-span deflection change of prestressed concrete beams under concentrated load is much larger than that under symmetric load. The ductility coefficient of prestressed concrete beams with plastic bellows decreases as the grouting compactness increases. In engineering practice, the quality of duct grouting compactness about the prestressed concrete beam should be strictly controlled and improved.