Articoli di riviste: "SEISMIC FORCE"

1

Hawkins, Neil M., e S. K. Ghosh. "Seismic-Force-Resisting Systems". PCI Journal 45, n. 5 (1 settembre 2000): 34–45. http://dx.doi.org/10.15554/pcij.09012000.34.45.

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Yan, Xian Li, Qing Ning Li, Chang Gao e Li Ying Wang. "Research on Dynamic Performance of Concrete-Filled Steel Tubular Trussed Arch Bridge under Earthquake". Advanced Materials Research 368-373 (ottobre 2011): 1222–26. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.1222.

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Taking a double span- swallows-type CFST (concrete-filled steel tubular) trussed arch bridge as an engineering example; a spatial finite element analysis model is established to calculate its dynamic characteristic. The seismic responses in different earthquake input directions are calculated based on the elastic dynamic time history method. Results show that: the out-plane stability of the bridge is weaker than that of the in-plane; the torsion resistance ability of the bridge deck is smaller than that of the arch ribs; the axial force-Fx, shear force-Fz and bending moment-My of the bridge are mainly controlled by longitudinal seismic forces, whereas the shear forces-Fy, bending moment-Mz and torque-Mx are mainly controlled by transverse seismic forces; vertical seismic force has a considerable effect on internal forces of the bridge, so it can not be ignored in seismic design.

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3

Bai, Bing, Ze Yu Wu e Xiao Shan Deng. "Longitudinal Seismic Forces of Long-Span Bridge". Advanced Materials Research 255-260 (maggio 2011): 1134–37. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.1134.

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Based on the numerical simulation and finite element method, the longitudinal seismic action of a long-span continuous bridge is systematically analyzed. Four load cases are considered, i.e. bridge without piers, bridge with piers, neglecting friction force and combining friction force and pier scouring respectively. Calculation results show that: when considering the piers, the contribution of piers to bridge longitudinal seismic forces is depending on the concrete problems; when the friction force of rubber supports is regarded, sliding support greatly enhances the longitudinal overall rigidity of the bridge, but the force is resolved to each rubber support and can improve the stress state of the fixed support; considering effect of scouring, the elongation of piers will lead to the decrease of longitudinal overall rigidity, thereby lowering the longitudinal seismic forces. From comparison of the two piers that, the relatively flexible structure has shock absorption to a certain extent, so it is more suitable for the bridge.

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4

Akhtar, Mohsin Aakib Shamim. "Dynamic Seismic Analysis of Multi Storey Buildings in Seismic Zone V". International Journal for Research in Applied Science and Engineering Technology 10, n. 2 (28 febbraio 2022): 108–15. http://dx.doi.org/10.22214/ijraset.2022.40154.

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Abstract: In India, multi-storied buildings area unit sometimes created because of high value and deficiency of land. Earthquake could be a phenomenon which might generate the foremost harmful forces on structures. Buildings ought to be created safe for lives by correct style and particularisation of structural members so as to possess a ductile sort of failure. To protect such civil structures from significant structural damage, the seismic response of these structures is analyzed along with wind force calculation and forces such as support reactions and joint displacement are calculated and included in the structural design for a vibration resistant structure. The primary objective is to make associate earthquake resistant structure by enterprise seismal study of the structure by static equivalent methodology of study and do the analysis and design of the building by using STAAD PRO software in both static and dynamic analysis Keywords: Dynamic Seismic Analysis, Staad.Pro.

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5

Xu, Qiang, e Xing Jun Qi. "Analysis on Seismic Pounding of Curved Bridge". Applied Mechanics and Materials 90-93 (settembre 2011): 800–804. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.800.

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Based on the impact phenomenon between the end of the beam and the bridge abutment of the curved continuous bridge during earthquakes, a spatial finite element calculating model with collision element is presented. The law of collision is studied by the nonlinear contact time history analysis method under two three-dimensional ground motions. The variation laws of relative displacement and the internal force at the bottoms of piers are researched. In addition the changing of displacement and internal force at the end diaphragm are studied. The results show that the pounding action can easily lead to significant collision forces between the end beam and the abutment of the curved bridge which increases the axial force of girder evidently. The collision forces and longitudinal displacements from the inner to outer of the diaphragm generally are showed by an increasing trend, and the pounding action is more fierce under Elcentro ground motion than that under Tianjin ground motion.There is no relative displacement of consolided pier, bending moment and shear force of the consolided pier are greater than that of the mobile pier.The conclusions from the present study may serve as a reference base for seismic design of continuous curved bridges.

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6

Chen, Hong Kai, Hong Mei Tang, Ting Hu, Yi Hu e Xiao Ying He. "Study on Numerical Simulation for Failure Process of Girder Bridge under Seismic Influence". Advanced Materials Research 530 (giugno 2012): 122–29. http://dx.doi.org/10.4028/www.scientific.net/amr.530.122.

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Based on the finite element analysis software Midas, it takes response spectrum analysis, and posts the failure mechanism and characteristics of Girder Bridge under intense earthquake. Through the seismic response spectrum displacement maps of Girder Bridge, it finds out that the abutment and foundation deformation is in evidence, especially the top of abutment foundation. Through the study of seismic internal force variation on girder and pier, it indicates that the longitudinal earthquake controls axial force, vertical shearing force and in-plane bending moment, transversal earthquake dominates transversal shearing force and out-planes bending moment. And it shows that the pier and mid-span section are seismic response sensitivity parts. The three parts, axial force, longitudinal shearing force and in-plane bending moment, becomes the controlling index of pier intensity. According to the seismic response spectrum displacement for pier and abutment, the transversal anti-seismic stiffness of pier is smaller than longitudinal one, longitudinal seismic force shows no effect on transversal displacement, and the transversal seismic force can augments longitudinal displacement. At the same condition, longitudinal seismic force changes the longitudinal distributing form of abutment and concaves it deeply, and the transversal seismic force can not change its shape, but augment its value.

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7

Paultre, Patrick, Éric Lapointe, Sébastien Mousseau e Yannick Boivin. "On calculating equivalent static seismic forces in the 2005 National Building Code of Canada". Canadian Journal of Civil Engineering 38, n. 4 (aprile 2011): 476–81. http://dx.doi.org/10.1139/l11-021.

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Several major changes were introduced in the seismic design provisions of the 2005 edition of the National Building Code of Canada (NBCC). The lateral earthquake design force at the base and the lateral force distribution along the building height depend on the design spectra and on modification factors that, in most cases, require a large number of interpolations and calculations. This note presents a spreadsheet that facilitates determination of the 2005 NBCC seismic design forces from the equivalent static force procedure.

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8

Liang, Jia. "Response and Parameter Analysis of Reinforced Retaining Wall under Earthquake Loading". Applied Mechanics and Materials 268-270 (dicembre 2012): 702–5. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.702.

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FEM is use for the mechanical analysis of reinforced retaining wall under earthquake loading. The main results are as following. The displacement and axial force increased with the increased seismic intensity. The displacement and axial force decreased with the increased the length of bar strip. The displacement and axial force decreased with the decreased the spacing of bar strip. The displacement and axial force decreased with the increased physical mechanics parameters of filling. Seismic response was similar under bilateral seismic loading and horizontal seismic loading, seismic response was slightly larger under bilateral seismic loading.

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9

Heidebrecht, A. C., e A. Rutenberg. "Evaluation of foundation tie requirements in seismic design". Canadian Journal of Civil Engineering 20, n. 1 (1 febbraio 1993): 73–81. http://dx.doi.org/10.1139/l93-008.

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A simple structural model is proposed to evaluate the axial force acting on tie beams interconnecting spread footings or pile caps due to differential ground motion estimated on the basis of the travelling wave assumption. The approach is intended to supplement the "ten percent rule" or similar multipliers specified by seismic codes as design axial forces on tie beams. It is shown that the axial force demand is rather modest. However, shear forces between footing and soil may be quite large depending on maximum column displacements and superstructure rigidity. Key words: foundations, tie beams, earthquake, travelling waves, seismic codes.

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10

Ustun, Ozgur, Omer Cihan Kivanc e Mert Safa Mokukcu. "A Linear Brushless Direct Current Motor Design Approach for Seismic Shake Tables". Applied Sciences 10, n. 21 (29 ottobre 2020): 7618. http://dx.doi.org/10.3390/app10217618.

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The progress in material and manufacturing technologies enables the emergence of new research areas in electromagnetic actuator applications. Permanent magnet (PM) linear motors are preferred to achieve precise position control and to meet the need for high dynamic forces in the seismic shake tables that are used in analyzing reactions of structure models. The design approaches on the linear motors used in the seismic shake tables may vary depending on the desired force, stroke and acceleration values. Especially, the maximum width, the maximum depth, the maximum linear motor length in longitudinal direction and the maximum travelling distance parameters are the primary design criteria in seismic shake table drive systems. In this paper, a design approach for a linear PM brushless direct current (BLDC) motor with high force/volume, force/weight and force/input power ratios is developed. The design was analyzed using two-dimensional (2D) and three-dimensional (3D) finite element method (FEM) approaches through the ANSYS Maxwell software. The mathematically designed linear BLDC motor was manufactured and subjected to displacement, acceleration and force tests that are used in seismic analyses. The results of the experimental tests validate the convenience of the proposed design approach and the selected parameters.

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11

Wang, Chang-xiang, Meijing Wang e Jianwen Liang. "Seismic analysis on cross joint of utility tunnel". MATEC Web of Conferences 295 (2019): 03004. http://dx.doi.org/10.1051/matecconf/201929503004.

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The finite element software ABAQUS is used to establish the seismic time-history analysis model of the utility tunnel joints. The viscoelastic boundary is employed to input the seismic wave through the equivalent nodal force. Considering the nonlinearity of the soil and concrete materials, the internal force of the cross-shaped utility tunnel is calculated, and the influence effect and influence range of the cross joints of the utility tunnel are also studied. Studies have shown that the internal forces near the cross joints increase significantly. The research has certain reference value for the seismic design of the cross joints in utility tunnel.

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12

Xin, Chun Lei, e Bo Gao. "Composite Lining Aseismic Design for Fault-Crossing Tunnel Structures". Advanced Materials Research 971-973 (giugno 2014): 30–34. http://dx.doi.org/10.4028/www.scientific.net/amr.971-973.30.

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Although underground structures have stronger aseismic performance than ground structures, seismic disasters of mountain tunnels were fairly conspicuous in Wenchuan Great Earthquake. On the basis of seismic disaster analysis, a composite lining designfor tunnel structures across active fault was put forward. Three-dimensional numerical simulation method was used to analyze aseismic and damping effect of this structure. The results show that: (1)After setting aseismic and damping structure, the maximum internal forces value in lining the pattern of internal forces will not change. (2)Aseismic and damping structure setting can directly reduce the bending moment value and increase the axial force and stress force value in lining structure. (3) Relative to aseismic and damping structure, grouting region around damping layer can ameliorate internal force condition in lining structure and improve the effect of aseismic and damping structure. The above research results contribute to provide reference for seismic fortification of tunnel structures across active faults.

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13

Deng, Jiang Dong, Zhou Hong Zong e Zhang Hua Xia. "Study on Seismic Strengthening Demand of Damage Concrete Bridge Piers". Applied Mechanics and Materials 178-181 (maggio 2012): 2070–74. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.2070.

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Initial damage often exists in the concrete piers of bridges in service. In this paper numerical analysis was used to study the seismic strengthening behavior of concrete bridge piers with different bending damage degrees, including seismic forces, pier top displacements, steel bar strain and energy dissipation, in order to obtain the strengthening demand to repair the damage piers. The results showing that: initial bending damage reduced the seismic force, increased the pier top displacements and the steel bar strain. After strengthening the pier top displacements and steel bar strain at the pier bottom decreased, energy dissipation increased, and the anti-seismic properties of damage piers effectively recovered, but the increase of the seismic force might make new plastic-hinges out the strengthened area. At last according to the mechanics properties the strengthening demand under different bending damage degrees was given.

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14

Burridge, R., e L. Knopoff. "Body Force Equivalents for Seismic Dislocations". Seismological Research Letters 74, n. 2 (1 marzo 2003): 154–62. http://dx.doi.org/10.1785/gssrl.74.2.154.

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15

Owen, Thomas E., e Edgar C. Schroeder. "Asymmetrical lateral force seismic source transducer". Journal of the Acoustical Society of America 83, n. 4 (aprile 1988): 1713. http://dx.doi.org/10.1121/1.395859.

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16

Ling, Hoe I., e Alexander H. D. Cheng. "Rock sliding induced by seismic force". International Journal of Rock Mechanics and Mining Sciences 34, n. 6 (settembre 1997): 1021–29. http://dx.doi.org/10.1016/s1365-1609(97)80011-1.

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17

Zhao, Jie, Gui Xuan Wang e Xu Hua Lu. "Seismic Analysis of Nuclear Project for Joint between Intake Tunnel and Circumfluence Groove". Advanced Materials Research 594-597 (novembre 2012): 1219–25. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.1219.

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By adopting dynamic time-history analysis method, the seismic analysis for the joint between intake tunnel and circumfluence groove is performed by FLAC3D. Aiming at the mechanical characteristics of this structure and rocky features, according to the design scheme, the analysis of seismic response is carried out, on the base of which envelopes of internal forces are given in this paper. The results show that change of the temperature has much influence on internal force in the same load effect combination. Temperature load also change the direction of internal force in some part. For the similar anti-seismic design, this paper has certain reference value and guiding sense.

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18

Fujii. "Prediction of the Maximum Seismic Member Force in a Superstructure of a Base-Isolated Frame Building by using Pushover Analysis". Buildings 9, n. 9 (5 settembre 2019): 201. http://dx.doi.org/10.3390/buildings9090201.

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It is essential for the seismic design of a base-isolated building that the seismic response of the superstructure remains within the elastic range. The evaluation of the maximum seismic member force in a superstructure is thus an important issue. The present study predicts the maximum seismic member force of five- and fourteen-story reinforced concrete base-isolated frame buildings adopting pushover analysis. In the first stage of the study, the nonlinear dynamic (time-history) analysis of the base-isolated frame buildings is carried out, and the nonlinear modal responses of the first and second modes are calculated from pushover analysis results. In the second stage, a set of pushover analyses is proposed considering the combination of the first and second modal responses, and predicted maximum member forces are compared with the nonlinear time-history analysis results. Results show that the maximum member forces predicted in the proposed set of pushover analyses are satisfactorily accurate, while the results predicted considering only the first mode are inaccurate.

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19

He, Jian, Yu Jiang, Qichao Xue, Chunwei Zhang e Jingcai Zhang. "Effectiveness of Using Polymer Bumpers to Mitigate Earthquake-Induced Pounding between Buildings of Unequal Heights". Advances in Civil Engineering 2018 (8 novembre 2018): 1–14. http://dx.doi.org/10.1155/2018/7871404.

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Collisions often happen between adjacent buildings without a sufficient gap under seismic loadings. Installing polymer bumpers may decrease the pounding forces between colliding buildings. This paper focuses on the analysis of suppressing pounding effects by using of polymer bumpers. In order to investigate pounding mitigation effectiveness in the condition with and without bumpers, different types of pounding force models are utilized to simulate and calculate frame vibration responses under seismic loads. Firstly, time-history results for pounding force, displacements, and shearing forces in selected floors are calculated in the condition with and without polymer bumpers. Secondly, differences between viscoelastic and elastic pounding force models are compared and discussed. And finally, parametric studies are carried out to investigate influences of different pounding parameters. The results show that polymer bumpers can reduce maximum values of pounding force but increase pounding times. And viscoelasticity of bumper materials has a certain range of influences on pounding force responses. Choosing improper material types and pounding parameters may lead to opposite effects.

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20

Ning, Hao, Xiao Yin Lv e Yi Jun Wang. "Research on Longitudinal Seismic Calculation Theory of Single-Story Factory Building". Applied Mechanics and Materials 166-169 (maggio 2012): 2471–77. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.2471.

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Regarding the distribution modes of longitudinal horizontal seismic forces of single-story factory building with no purlin concrete roof, there are conflicts between Sections 9.8.1 and 5.2.6 in the Seismic Design of Buildings GB50011-2010[1]. We suggested distributing the longitudinal seismic forces according to the proportion of the gravity loads on the subordinate areas of the lateral force components. We recommended replacing clause 1 of section 9.1.8 with “Don’t consider the effective stiffness of the enclosure walls or the partition walls”. Then for the example in Single-story Factory building Design Examples, we calculated the longitudinal seismic forces with two methods, and proved the our recommended method was correct.

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21

Jiang, Zhi Nan, e Zhong Hai Zhao. "Comparison of Base Shear Force Method in the Seismic Design Codes of China, America and Europe". Applied Mechanics and Materials 166-169 (maggio 2012): 2345–52. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.2345.

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Seismic design response spectrum and earthquake action in Chinese new seismic code (GB50011-2010), ASCE/SEI7-05 and Eurcode8 were gathered in this paper. Using base shear force method of each code, the authors computed the horizontal seismic forces of a three-story reinforced concrete frame building under the same conditions. The results show that the three static methods roughly approach, while the different parameters lead to discrepancies in calculated values.

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Li, Jun Qiang, Yi Fan Li e Yong Peng. "Theoretical Analysis of Seismic Response for Marine Drilling Risers". Applied Mechanics and Materials 423-426 (settembre 2013): 1531–36. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1531.

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With the continuous development of the marine oil industry, risers have become necessary equipment in offshore drilling engineering. On the basis of mode-superposition response spectrum method which is used commonly in anti-seismic design, the seismic responses of the marine drilling riser is analyzed on the theoretical and the related anti-seismic calculation formulas of the discrete system are promoted to the continuous system. The earthquake force and the resultant internal forces when the earthquake happening are analyzed and calculated. The calculation formulas of shear force and bending moment for each cross section of a riser under the earthquake action are deduced, which can offers some theoretical reference for riser engineering design when considering earthquake action.

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23

He, Jian, Yu Jiang, Qichao Xue, Chunwei Zhang e Jingcai Zhang. "Energy response analysis of adjacent structures with polymer bumpers under seismic loadings". Advances in Mechanical Engineering 10, n. 12 (dicembre 2018): 168781401880915. http://dx.doi.org/10.1177/1687814018809157.

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Insufficient gap between adjacent buildings may lead serious poundings under seismic loadings. Installing polymer bumpers may decrease the pounding forces between colliding buildings, which can prevent column yielding from overlarge shearing forces. This article focuses on the analysis on energy responses of adjacent structures equipped with polymer bumpers. Based on a novel pounding analysis method, systematic comparisons of structural pounding performance are conducted and specific results are obtained and discussed. First, time history responses for pounding force, displacements, and yielding shearing forces in selected floors are calculated. Then, energy response analysis considering viscoelasticity of bumpers is investigated. Afterward, under different seismic waves, input energy response, pounding force procedures, and story displacements are studied and discussed. And finally, parametric studies on energy responses, including gaps, sizes, and viscoelasticity parameters, are carried out to investigate influence sensitiveness of bumper parameters. The results show that the novel viscoelastic pounding force model is effective in simulating and calculating adjacent structural pounding with polymer bumpers. Although, in many cases, viscoelasticity has little effect on pounding forces and energy response time histories, it still has certain influences on maximum values. And, equipping with polymer bumpers on adjacent buildings can decrease maximum pounding forces under all types of seismic waves, but pounding times and maximum displacements of stories increase after being equipped with bumpers. By comparing cases under different seismic waves, energy responses show sensitive characteristics to different earthquake waves. Besides, gaps, sizes of bumpers also have significant influence on energy performance. They affect peak yielding energy and peak damping energy significantly.

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Xiao, Jie Ling, Xian Kui Wei, Ping Wang e Meng Nan Zhang. "Research on Longitudinal Seismic Response of Continuous Welded Rail on Bridge with High-Pier and Long-Span". Advanced Materials Research 838-841 (novembre 2013): 1063–68. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.1063.

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Longitudinal seismic responses of CWR on bridges with high-piers and long-spans under uniform excitation and traveling wave effect were studied. Results are shown as follows: Under seismic action, rail longitudinal forces near beam joints increase greatly than rail expansion forces (due to beam expansion); Designing CWR on bridges with high-piers and long-spans needs to consider influences of traveling wave effect and wave spreading derection; With the increase of the apparent velocity of seismic waves, rail longitudinal force tends to decrease; We suggest that designing of CWR on bridges crossing high-intensity earthquake zone should consider impact of seismic action, and establish a reasonable check method.

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Wang, Guofu, Jinhua Shang, Xianfeng Ma e Xiyong Xu. "Equivalent Inertial Force Method of Seismic Calculation for Subway Station in Soft Site". Shock and Vibration 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/4751071.

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On the basis of the structural characteristics of subway stations, structural inertial force can be simplified as multiple concentrated force acting on the member connecting node by using equivalent inertial force method of seismic calculation in soft site, and then internal forces of the structure will be analyzed. According to the principle that the maximum bending moment values of equivalent inertial force method and dynamic time-history analysis method are equal and the location is the same, the value of equivalent inertial force is determined, and the shear and axial force are ensured by introducing correction factor. The result shows that the calculation results of equivalent inertial force method are accurate and reliable. It can meet the design requirements and improve computational efficiency.

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Lin, Zhenwei, Chao Zhang, Jucan Dong, Jianliang Ou e Li Yu. "Dynamic Response Analysis of a Multiple Square Loops-String Dome under Seismic Excitation". Symmetry 13, n. 11 (1 novembre 2021): 2062. http://dx.doi.org/10.3390/sym13112062.

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The interaction between multiple loops and string cables complicates the dynamic response of triple square loops-string dome structures under seismic excitation. The internal connection between the multiple square loops-string cables and the grid beams was studies to provide a favorable reference for an anti-seismic structure. With a finite element model of the Fuzhou Strait Olympic Sports Center Gymnasium, established by SAP2000 software, the structural dynamic characteristic parameters were obtained first, and then this study adopted a time-history analysis method to study the internal force response of the cables and the roof grid beams of the multiple square loops-string dome (MSLSD) under three types of seismic array excitation. The influence of two factors, namely the seismic pulse and the near and far seismic fields, on the dynamic response of this structure was analyzed by three groups of different types of seismic excitation (PNF, NNF, PFF). As shown from the results, the first three-order vibration modes were torsional deformations caused by cables, the last five were mainly the overall roof plane vibration and antisymmetric vibration. Under the excitation of the three seismic arrays, the internal force responses of stay cables, square cables in the outer ring and the string cables were largest, while the maximum internal force response of the struts changed with the direction of seismic excitation. The largest internal force response of the roof grid beams occurred in local components such as BX3, BX7 and BY7, and the largest deformation of the beam nodes occurred in JX7, JX12 and JY4. In general, the seismic pulse and the near seismic field weakened the internal force response of the struts and cables but increased the internal force response and deformation of the dome beams, while the near and far seismic fields outweighed the seismic pulse. All the above provides an important reference for structural monitoring and seismic resistance.

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Yang, Xi Wen, e Zi Bao Lian. "Seismic Displacements Reduction for a Long-Span Cable-Stayed Bridge". Advanced Materials Research 255-260 (maggio 2011): 840–45. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.840.

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Floating or semi-floating systems are usually employed for long-span cable-stayed bridges to lengthen their fundamental periods, and accordingly, to reduce their seismic inertial force, but the structures’ seismic displacements could be increased by utilizing these systems. Taking Yong-jiang railway cable-stayed bridge which has a low center of gravity as engineering background, the function of viscous dampers in controlling seismic displacements is studied. Firstly, the rational parameters of dampers are determined by parametric analysis, and then the seismic displacements and forces of the bridge, utilizing and un-utilizing viscous dampers, are compared. The results show that: viscous dampers are efficient in controlling seismic displacements of the bridge; the seismic shear forces at the bottom of towers are reduced slightly and the corresponding moments are reduced in a larger extent for cable-stayed bridge with low center of gravity.

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Karande, Hrishikesh, e A. U. Bhalerao. "Analysis of RCC Building with Regular and Dumbbell Shaped Shear Wall in Different Types of Zones Using ETABS Software". International Journal for Research in Applied Science and Engineering Technology 11, n. 6 (30 giugno 2023): 14–22. http://dx.doi.org/10.22214/ijraset.2023.52921.

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Abstract: In structural engineering, a shear wall is a vertical element of a seismic force resisting system that is designed to resist in-plane lateral forces, typically wind and seismic loads. In many jurisdictions, the International Building Code and International Residential Code govern the design of shear walls. A shear wall resists loads parallel to the plane of the wall. Collectors also known as drag members; transfer the diaphragm shear to shear walls and other vertical elements of the seismic force resisting system. Shear walls are typically light-framed walls with shear panels, reinforced concrete walls, and reinforced masonry walls. The G+15 story structures situated in earthquake zones III, IV and V will be considered for study. All frames are designed under same gravity loading. Response spectrum method is used for seismic analysis. ETABS software is used and the results are compared. The results were obtained in the form of top story displacement, Story drift, Base shear and displacement

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Tong, Gen-shu, e Huang Jin-qiao. "Seismic force modification factor for ductile structures". Journal of Zhejiang University-SCIENCE A 6, n. 8 (agosto 2005): 813–25. http://dx.doi.org/10.1631/jzus.2005.a0813.

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Diwakar Chaudhary et al.,, Diwakar Chaudhary et al ,. "Performance of Tubular Structure under Seismic Force". International Journal of Mechanical and Production Engineering Research and Development 10, n. 3 (2020): 8983–92. http://dx.doi.org/10.24247/ijmperdjun2020854.

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Kim, Dae-Kon. "KBC Seismic Design Force for Nonstructural Element". Journal of the Korean Association for Spatial Structures 14, n. 1 (15 marzo 2014): 77–84. http://dx.doi.org/10.9712/kass.2014.14.1.077.

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Borzi, B., e A. S. Elnashai. "Refined force reduction factors for seismic design". Engineering Structures 22, n. 10 (ottobre 2000): 1244–60. http://dx.doi.org/10.1016/s0141-0296(99)00075-9.

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Chowdhury, Indrajit, e Shambhu P. Dasgupta. "Seismic Response of Piles Under Earthquake Force". Indian Geotechnical Journal 42, n. 2 (19 maggio 2012): 57–74. http://dx.doi.org/10.1007/s40098-012-0009-3.

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Ghosh, Sima, e Richi Prasad Sharma. "Force Polygon and Seismic Active Earth Pressure on the Back of a Retaining Wall Supporting c-F Backfill". International Journal of Geotechnical Earthquake Engineering 2, n. 1 (gennaio 2011): 20–28. http://dx.doi.org/10.4018/jgee.2011010102.

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The study presents a rational graphical approach to discover the dynamic active earth pressure on the back of a battered face retaining wall having inclined c-F backfill with surcharge load over the top of backfill. Considering the seismic forces as time independent inertia forces acting at the c.g. of the wedge soil, the law of force polygon is applied in the evaluation of seismic active earth pressure. A depth of tension crack in case of c-F backfill is also considered. A detailed parametric study has been made for the variation of seismic active earth pressure coefficients with respect to c, ca, F, d, kh, kv.

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35

Son, Kwang Ik, Byung Seung Kong, Won Suk Jang, Hee Joong Kim e Hack Soo Lee. "Probabilistic Approach for Cost Optimization of Structural Materials Using Plastic Hinge Mechanism". Advanced Materials Research 538-541 (giugno 2012): 3244–48. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.3244.

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In the seismic design, it is important to consider higher risks of damage under seismic design forces than under other general loads, such as live load, dead load, or wind load. Although the full strength of the structure can be developed to resist various types of earthquake forces with respect to increased safety factor, this design concept may be not appropriate when we consider the economic benefit since the design under the seismic force is normally 15 to 25 % more expensive than the design of elastic response. As a one of the seismic design approaches, plastic hinge mechanism has drawn an interest to ensure the economic design performance under the earthquake. In this paper, forecasted seismic motion was simulated using a Monte Carlo simulation to determine the seismic design load applied to the structure system. Then for each seismic load, the economical set of plastic hinge mechanisms was optimized using linear programming.

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36

Wang, Fei, Zhi Fang e Xin Feng Yin. "Experimental Study on Seismic Performance of Reactive Power Concrete Box Piers". Applied Mechanics and Materials 94-96 (settembre 2011): 464–68. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.464.

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Designing the reasonable cross-section and the structural conformation, three Reactive power concrete box piers samples were designed and studied under the constant axial force and reversed horizontal loads. The effect of the reversed horizontal load on the seismic performance of RPC box pier was studied. Such seismic performance as ductility, hysteresis curve, skeleton curve, etc. of RPC box piers is studied by pseudo-static test on three RPC box piers. The simulation results shows that RPC box piers exists excellent performance of resisting seismic force, the direction of horizontal load significant affect that performance, and the performance of resisting seismic force for the pier loaded by the force from main axial direction are better than that from other direction.

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37

Yan, Bin, e Peng Liu. "Study on Seismic Performance of Double Spherical Bearing". Advanced Materials Research 255-260 (maggio 2011): 2488–91. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.2488.

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Continuous Beam Bridge was widely used, while seismic problem of it was prominent in meizoseismal area. According to mechanism of DSB, seismic performance of DSB was studied and the parameters of DSB were analyzed later, based on non-navigable bridge of Hong Kong-Zhuhai-Macau Bridge in deep water. It was found that DSB was an effective seismic-isolation device which could significantly reduce the seismic force although seismic displacement of bridge was increased. Yielding force and post-yielding stiffness were two main parameters of DSB.

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38

Priestley, M. J. N. "Performance based seismic design". Bulletin of the New Zealand Society for Earthquake Engineering 33, n. 3 (30 settembre 2000): 325–46. http://dx.doi.org/10.5459/bnzsee.33.3.325-346.

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One of the major developments in seismic design over the past 10 years has been increased emphasis on limit states design, now generally termed Performance Based Engineering. Three techniques - the capacity spectrum approach, the N2 method and direct displacement-based design have now matured to the stage where seismic assessment of existing structures, or design of new structures can be carried out to ensure that particular deformation-based criteria are met. The paper will outline and compare the three methods, and discuss them in the context of traditional force-based seismic design and earlier design approaches which contained some elements of performance based design. Factors defining different performance states will be discussed, including the need, not yet achieved, to include residual displacement as a key performance limit. Some emphasis will be placed on soil-related problems, and the incorporation of soil/structure interaction into performance-based design. It will be shown that this is relatively straightforward and results in consistent design solutions not readily available with force-based designs using force-reduction factors.

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39

Das, Satrajit, e James M. Nau. "Seismic Design Aspects of Vertically Irregular Reinforced Concrete Buildings". Earthquake Spectra 19, n. 3 (agosto 2003): 455–77. http://dx.doi.org/10.1193/1.1595650.

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Seismic building codes such as the Uniform Building Code (UBC) do not allow the equivalent lateral force (ELF) procedure to be used for structures with vertical irregularities. The purpose of this study is to investigate the definition of irregular structures for different vertical irregularities: stiffness, strength, mass, and that due to the presence of nonstructural masonry infills. An ensemble of 78 buildings with various interstory stiffness, strength, and mass ratios is considered for a detailed parametric study. The lateral force-resisting systems (LFRS) considered are special moment-resisting frames (SMRF). These LFRS are designed based on the forces obtained from the ELF procedure. The results from linear and nonlinear dynamic analyses of these engineered buildings exhibit that most structures considered in this study performed well when subjected to the design earthquake. Hence, the restrictions on the applicability of the equivalent lateral force procedure are unnecessarily conservative for certain types of vertical irregularities considered.

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40

Razavian Amrei, Seyed Amin, Reza Vahdani, Mohsen Gerami e Gholamreza Ghodrati Amiri. "Correlation Effects of Near-Field Seismic Components in Circular Metro Tunnels: A Case Study—Tehran Metro Tunnels". Shock and Vibration 2020 (30 maggio 2020): 1–13. http://dx.doi.org/10.1155/2020/3016465.

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Seismic evaluation of underground structures such as tunnels requires nonlinear dynamic analysis, due to the complex dynamic behavior of soil and the interaction of soil and structure. Simulation of the seismic response of the structure using nonlinear dynamic analysis is possible only with proper acceleration time history. Considering the vertical component of the earthquake (such as near-fault earthquakes) on the site is an important factor to achieve real structural responses. In the current study, soil-tunnel system has been modeled in ABAQUS software, considering Mohr–Coulomb nonlinear model for soil and concrete damage plasticity model for tunnel lining. In order to investigate the effect of seismic components correlation under different combinations of loads on the acceleration, axial force, and maximum shear force in tunnel lining, nonlinear dynamic analysis has been performed under four near-field earthquakes with different horizontal and vertical component ratios, considering 15 load combinations. The results show that increasing the vertical-horizontal component ratio has an insignificant effect on the maximum horizontal acceleration experienced by the tunnel lining. Also, the results of axial forces and shear forces indicate that increasing the ratio of vertical to horizontal components of the earthquake is the most effective factor on the axial force response.

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41

Goel, Rakesh K., e Anil K. Chopra. "Extension of Modal Pushover Analysis to Compute Member Forces". Earthquake Spectra 21, n. 1 (febbraio 2005): 125–39. http://dx.doi.org/10.1193/1.1851545.

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This paper extends the modal pushover analysis (MPA) procedure for estimating seismic deformation demands for buildings to compute member forces. Seismic demands are computed for six buildings, each analyzed for 20 ground motions. A comparison of seismic demands computed by the MPA and nonlinear response history analysis (RHA) demonstrates that the MPA procedure provides good estimates of the member forces. The bias (or error) in forces is generally less than that noted in earlier investigations of story drifts and is comparable to the error in the standard response spectrum analysis (RSA) for elastic buildings. The four FEMA-356 force distributions, on the other hand, provide estimates of member forces that may be one-half to one-fourth of the value from nonlinear RHA.

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42

Huang, Jinshan, Yongping Rao, Hao Qiu e Ying Lei. "Generalized algorithms for the identification of seismic ground excitations to building structures based on generalized Kalman filtering under unknown input". Advances in Structural Engineering 23, n. 10 (3 marzo 2020): 2163–73. http://dx.doi.org/10.1177/1369433220906225.

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The exact information of seismic excitation and structural state is a prerequisite for structural seismic safety assessment and vibration control. When the seismic excitation to a structure is not measured, the seismic excitation can be identified as an inversed problem from measured structural responses. Although some relevant approaches have been developed, there are certain limitations or drawbacks in the existing approaches. To circumvent these problems, two generalized algorithms are proposed for the identification of seismic ground excitation to multi-story and tall buildings, respectively. When the seismic ground excitation to a structure is not measured, the data measured by a structural health monitoring system are structural absolute responses. So the structural motion equation in the absolute coordinate system is derived, in which the unknown seismic ground excitation is treated as unknown external force acting on the structure. First, the identification of unknown seismic excitations to multi-story building structures is studied. A generalized Kalman filtering under unknown input is proposed for the identification of structural state and unknown seismic excitation without the observation of structural absolute acceleration responses at the location of unknown external force. The derivation of the proposed generalized Kalman filtering under unknown input is based on the classical Kalman filter, but is more general than the existing identification approaches based on Kalman filter with unknown input in the deployments of accelerometers in the building structure. Then, it is extended to explore the identification of unknown seismic excitations to tall building structures. To avoid substructural identification from the top to bottom in a sequential manner, the motion equation in absolute coordinate system is reduced by modal expansion. Moreover, instead of the identification of unknown modal forces in previous approaches, the seismic excitation is directly identified without increasing the number of unknown forces. To demonstrate the proposed algorithms, numerical examples of identifying seismic excitations to a 6-story shear building and an 18-story tall building are investigated.

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43

Ghobarah, A. "Seismic behaviour of highway bridges with base isolation". Canadian Journal of Civil Engineering 15, n. 1 (1 febbraio 1988): 72–78. http://dx.doi.org/10.1139/l88-008.

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A study is made on the seismic behaviour of highway bridges with lead–rubber base isolation. The system of base isolation is considered as a bilinear spring. Single- and two-span highway bridges subjected to representative strong earthquake ground motion records were analyzed. The effect of various parameters such as the isolator's stiffness, pier stiffness, and pier eccentricity on the system response was evaluated.It was found that the use of base isolation shifts the fundamental frequency of the bridge system towards the longer period. Proper design of the base isolation tends to reduce the design forces on the bridge piers and is accompanied by larger displacements. Simplified design guidelines are adequate as long as the bridge system can be represented by a single degree of freedom model. The reduction in pier stiffness of a two-span bridge may increase the displacement and the force transmitted to the abutment. The increased forces at the abutments are accompanied by reduction in the shear force transmitted to the pier. Increased displacements and forces may also result when the location of the pier departs from the centre and unequal spans are created. In this case, the maximum displacements and forces occur at the abutment adjacent to the long span. Key words: dynamic, seismic, response, highway, bridges, earthquake, base isolation, design.

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44

Lin, Li, Jichao Zhang, Yadong Li, Zhuwei Rao e Zheng Sen. "3D Finite Element Analysis of Seismic Response of Rigid Pile Composite Foundation with Microprobe Group". International Journal of Analytical Chemistry 2022 (8 luglio 2022): 1–9. http://dx.doi.org/10.1155/2022/6129134.

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In order to study the seismic performance of the rigid pile composite foundation, a three-dimensional finite element analysis of the seismic response of the rigid pile composite foundation with microprobe group was proposed. The three-dimensional finite element method is used to analyze the dynamic response law of pile group rigid pile composite foundation under the action of the earthquake, especially the internal force response of the pile body. It is worth noting that when the internal force response of pile decreases significantly, the maximum internal force of the whole pile is also significantly smaller than the maximum internal force of pile foundation. However, when the pile body is located on a layered foundation and the modulus of adjacent soil layers differs greatly, the earthquake action will cause the pile body to generate a large internal force. The seismic performance of the rigid pile composite foundation is feasible, and it can be extended and applied to the similar seismic performance test of other composite foundations.

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45

Novikasari, Inas, e Anis Rosyidah. "Link Slab Capacity In Bridges Supported By Lead Rubber Bearing And Elastomer". Wahana Teknik Sipil: Jurnal Pengembangan Teknik Sipil 24, n. 2 (31 dicembre 2019): 73. http://dx.doi.org/10.32497/wahanats.v24i2.1725.

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Debris accumulation in bridge slab gaps which use expansion joints can restrain deck expansion, causing undesirable forces on floor deck and damage to the structure. In order to avoid the worst possibility that can occur, an alternative using link slab is utilized. The use of link slab at high level seismic force location, requires the Seismic Isolation System on bridge to reduce the seismic force. The application of Seismic Isolation System can be conducted by Lead Rubber Bearing (LRB) type of seismic isolator. This study compares the use of Lead Rubber Bearing (LRB) and elastomer on bridge link slabs against the dimension of the link slab. In this study structural modeling used 2 models: bridges supported by elastomer and bridges supported by LRB with software-made. The link slab analysis approach used were analytical methods or classical methods. Based on results of the analysis, the width of the crack that occured on bridge supported by LRB is 0.218 mm while on the bridge supported by elastomer is 0.269 mm. The use of Lead Rubber Bearing (LRB) type of support will give more advantages to the design of the link slab since it results in smaller crack design criteria.

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46

Goudarzi, M. A., S. R. Sabbagh-Yazdi e W. Marx. "Seismic Analysis of Hydrodynamic Sloshing Force on Storage Tank Roofs". Earthquake Spectra 26, n. 1 (febbraio 2010): 131–52. http://dx.doi.org/10.1193/1.3283902.

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Large-amplitude sloshing caused by earthquakes may result in liquid impact on the roof of liquid storage tanks. The motivation for this study is better understanding of the sloshing-induced impact via experimental investigations and establishing an analytical approach for evaluation of the maximum impact force on tank roofs. The experimental tests are carried out using a rectangular liquid tank excited by harmonic oscillations. The effects of geometric parameters such as the tank aspect ratio, excitation amplitude and freeboard on maximum liquid impact force are investigated by conducting 140 tests. Based on the conservation of fluid momentum, an analytical solution is developed to model sloshing impact force on tank roofs. The analytical solution parameters are calibrated using the experimental measurements. Finally, the analytical scheme is extended for a systematic process to evaluate the hydrodynamic and hydrostatic components of impact forces for earthquake engineering application.

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47

Hardage, Bob A., e Donald Wagner. "S-S imaging with vertical-force sources". Interpretation 2, n. 2 (1 maggio 2014): SE29—SE38. http://dx.doi.org/10.1190/int-2013-0097.1.

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We show examples of S-S images created from multicomponent seismic data generated by vertical-force sources that can be quite useful to seismic interpreters. Two source types are used: vertical vibrators and shot-hole explosives. We first discuss S-S images made from data generated by a vertical vibrator and recorded with vertical receiver arrays of 3C geophones. We next show images extracted from surface-based 3C geophones deployed around this VSP well as a 3D seismic grid. The energy sources used to generate these surface 3D seismic data were shot-hole explosives. In all data examples, we observe that each type of vertical-force source (vertical vibrator and shot-hole explosive) produces abundant direct-S energy on radial and transverse geophones. We find only minimal amounts of P-wave energy on transverse-receiver data. In contrast, radial-receiver data have significant P-wave events intermingled with radial-S events. The minimal amount of P-wave noise on transverse-receiver data makes it easier to study S-S wave physics and to create S-S images with transverse-S data. The data examples focus on transverse-S data created by vertical-force sources because interpreters will find it more convenient to process and use this S-mode. Subsequent publications will assign equal weight to radial-S and transverse-S data.

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48

Jia, Liang, Shikai He, Na Li, Wei Wang e Kai Yao. "Stability of Reinforced Retaining Wall under Seismic Loads". Applied Sciences 9, n. 11 (28 maggio 2019): 2175. http://dx.doi.org/10.3390/app9112175.

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Based on the horizontal slice method (HSM) and assuming a log spiral slip surface, a method to analyze the stability of a reinforced retaining wall under seismic loads was established in this study by calculating the tensile force of the reinforcement. A parametric study was conducted on the normalized tensile force of the reinforcement, and it was observed that the normalized tensile force tends to increase with acceleration of the seismic load and the height of the backfill. Moreover, it also increases with soil unit weight, while it decreases with increased friction angle of the backfill soil, and the influence of soil cohesion on the normalized tensile force is not significant. The HSM method is proved to be suitable for analyzing the tensile force of reinforcement in retaining walls under seismic loads.

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49

Sultanov, Karim Sultanovich, e Nikolai Ivanovich Vatin. "Wave Theory of Seismic Resistance of Underground Pipelines". Applied Sciences 11, n. 4 (18 febbraio 2021): 1797. http://dx.doi.org/10.3390/app11041797.

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The object of the research is an underground straight horizontal pipeline subjected to seismic impact. The research method was analytical. The results were compared with the experimental results of other authors and computer calculations. It was shown that the main disadvantage of the dynamic theory of seismic resistance of underground pipelines is the neglect of the dynamic stress state in soil under seismic wave propagation. The next drawback of the dynamic theory is an inaccurate, approximate accounting for the displacement of the soil medium to which the underground pipeline is embedded. The complete interaction process includes the stages of nonlinear changes in the interaction force (the friction force) by manifesting its peak value and the Coulomb friction. The contact layer of soil undergoes shear deformations until complete structural destruction of the soil contact layer. The interaction force is the friction force, and its peak value does not appear. The seismic resistance of underground pipelines should be considered based on the theory of propagating seismic waves in a soil medium and the interaction of seismic waves with underground pipelines, i.e., based on the wave theory of seismic resistance of underground pipelines. A one-dimensional coupled problem of seismic resistance of underground pipelines under seismic impacts was posed based on the wave theory. An algorithm and a program for the numerical solution of the stated wave problems were developed using the method of characteristics and the method of finite differences. An analysis of the laws of interaction of underground pipelines with soil under seismic influences shows that it is necessary to use in the calculations the laws of interaction that account for the complete interaction processes observed in experiments. The analysis of the obtained numerical solutions and the posed coupled problems of the wave theory of seismic resistance of underground pipelines show the occurrence mechanisms of longitudinal stresses in underground pipelines under seismic influences. The results of calculations stated that an account for the dynamic stress normal to the underground pipeline’s outer surface leads to multiple increases in longitudinal stress in the underground pipeline. This multiple increase is due to the transformation of the interaction force into an active frictional force, resulting from a greater strain in soil than the one in the underground pipeline. Based on the analysis results, a theory of the seismic wave propagation process in an underground pipeline and surrounding soil was proposed.

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Zinco, Adamo, Fernando Fraternali, Gianmario Benzoni e Enzo Martinelli. "On the Distribution in Height of Base Shear Forces in Linear Static Analysis of Base-Isolated Structures". Buildings 10, n. 11 (1 novembre 2020): 197. http://dx.doi.org/10.3390/buildings10110197.

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Abstract (sommario):

Although base isolation is nowadays a well-established seismic-protection technique for both buildings and bridges, and several issues are still open and attract the interest of the research community. Among them, the formulation of computationally efficient and accurate analysis methods is a relevant aspect in structural design of seismic-isolated buildings. In fact, codes and guidelines currently in force in various parts of the world generally include the possibility for designers to utilize linear-elastic analysis methods based on equivalent linearization of the non-linear force-displacement response of isolators. This paper proposes a formula for defining the force distribution in height that should be considered in linear-static analyses to obtain a more accurate approximation of the actual structural response, supposedly simulated by means of non-linear time history analysis. To do that, it summarizes the results of a wide parametric analysis carried out on a batch of structures characterized by three different heights and various properties of base isolators. The reported results highlight that the equivalent static force distribution provided by both Italian and European codes tend to underestimate the actual seismic lateral forces acting on base-isolated buildings, whereas the inverted triangular distribution, proposed in various American codes and standards, is often conservative.

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