Journal articles: 'Seismic forces'

1

Olmos, Bertha A., and Jose Manuel Roesset. "Seismic forces on piles." Structure and Infrastructure Engineering 9, no. 12 (December 2013): 1283–98. http://dx.doi.org/10.1080/15732479.2012.688976.

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McRae, Hamish. "Seismic forces of global change." Strategy & Leadership 24, no. 6 (March 1996): 6–11. http://dx.doi.org/10.1108/eb054569.

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Bolotbek, T., K. M. Mirlanov, A. Y. Telin, E. S. Chukanov, and A. T. Talgatov. "SPECTRAL METHODS FOR DETERMINING THE SEISMIC FORCES OF BUILDINGS." Herald of KSUCTA, №2, Part 1, 2022, no. 2-1-2022 (April 30, 2022): 426–34. http://dx.doi.org/10.35803/1694-5298.2022.2.426-434.

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The article discusses methods for calculating seismic effects on buildings and structures along the spectral curve, creating a dynamic calculation scheme for load-bearing structural elements, inertial reactions and displacements of building structures, natural and forced vibrations of buildings under the effect of seismic forces.

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Cheng, Yuan Bing, Hong Wei Du, Shi Yun Zhang, and Liu Zhong Xu. "Seismic Design of R.C. Stairs in Masonry Structure." Advanced Materials Research 163-167 (December 2010): 4133–37. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.4133.

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In view of masonry structures with rigid floor slab, seismic behavior of R. C. stairs and influence of stairs on the stiffness of lateral walls of stair well was analyzed, calculation formulae of the seismic internal forces of stairs were deduced, calculation method of the seismic shear forces considering the seismic effect of stairs on main structure were given out. Analysis and comparison on engineering ensamples were carried out. The results show K-type bracing function of step slabs to main structure is evident. Considering the bracing function, shear deformation of the floor layer and shear forces in the seismic walls are decreased, internal forces in R. C. stairs are increased. Seismic design recommendation of step slab to decrease the seismic forces was presented.

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Jaiswal, O. R., Durgesh C. Rai, and Sudhir K. Jain. "Review of Seismic Codes on Liquid-Containing Tanks." Earthquake Spectra 23, no. 1 (February 2007): 239–60. http://dx.doi.org/10.1193/1.2428341.

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Liquid storage tanks generally possess lower energy-dissipating capacity than conventional buildings. During lateral seismic excitation, tanks are subjected to hydrodynamic forces. These two aspects are recognized by most seismic codes on liquid storage tanks and, accordingly, provisions specify higher seismic forces than buildings and require modeling of hydrodynamic forces in analysis. In this paper, provisions of ten seismic codes on tanks are reviewed and compared. This review has revealed that there are significant differences among these codes on design seismic forces for various types of tanks. Reasons for these differences are critically examined and the need for a unified approach for seismic design of tanks is highlighted.

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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, no. 2 (February 28, 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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Chin, C. Y., Claudia Kayser, and Michael Pender. "Seismic earth forces against embedded retaining walls." Bulletin of the New Zealand Society for Earthquake Engineering 49, no. 2 (June 30, 2016): 200–210. http://dx.doi.org/10.5459/bnzsee.49.2.200-210.

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This paper provides results from carrying out two-dimensional dynamic finite element analyses to determine the applicability of simple pseudo-static analyses for assessing seismic earth forces acting on embedded cantilever and propped retaining walls appropriate for New Zealand. In particular, this study seeks to determine if the free-field Peak Ground Acceleration (PGAff) commonly used in these pseudo-static analyses can be optimized. The dynamic finite element analyses considered embedded cantilever and propped walls in shallow (Class C) and deep (Class D) soils (NZS 1170.5:2004). Three geographical zones in New Zealand were considered. A total of 946 finite element runs confirmed that optimized seismic coefficients based on fractions of PGAff can be used in pseudo-static analyses to provide moderately conservative estimates of seismic earth forces acting on retaining walls. Seismic earth forces were found to be sensitive to and dependent on wall displacements, geographical zones and soil classes. A reclassification of wall displacement ranges associated with different geographical zones, soil classes and each of the three pseudo-static methods of calculations (Rigid, Stiff and Flexible wall pseudo-static solutions) is presented. The use of different ensembles of acceleration-time histories appropriate for the different geographic zones resulted in significantly different calculated seismic earth forces, confirming the importance of using geographic-specific motions. The recommended location of the total dynamic active force (comprising both static and dynamic forces) for all cases is 0.7H from the top of the wall (where H is the retained soil height).

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Bai, Bing, Ze Yu Wu, and Xiao Shan Deng. "Longitudinal Seismic Forces of Long-Span Bridge." Advanced Materials Research 255-260 (May 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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Chernov, Yury T., and Jaafar Qbaily. "Evaluation of seismic forces under modified structural schemes in the process of vibrations." Structural Mechanics of Engineering Constructions and Buildings 17, no. 4 (December 15, 2021): 391–403. http://dx.doi.org/10.22363/1815-5235-2021-17-4-391-403.

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The aim of the work - development of one of the possible methods for seismic analysis that considers the inelastic behavior of structures under seismic loads. This requires the development of seismic analysis methods that take into account the change (decrease) in the bearing capacity or the destruction of individual elements until the final loss of the bearing capacity of the structure. Methods. The dependences and algorithms include determining seismic forces using the method of normal forms, which until now is the main one in solving problems of the seismic resistance theory in seismic regions, calculation formulas to calculate seismic forces at each time step are presented in the form of expansions into natural vibration modes, which regard the changes in the design scheme. The calculation is repeated at each time step as a static calculation for the action of seismic forces determined at the previous stage, before the building collapses. Results. The developed dependencies and algorithms allow to consider changes in the design scheme during vibrations at each time step, changes in the dynamic properties of the building and, as a result, the values of seismic forces. The value of the coefficient of inelastic work of structures K 1, which are given in regulatory documents, do not give fully correspond to the actual behavior of the structure under seismic influences. The proposed calculation method allows to determine the estimated values of seismic forces and their distribution taking into account the influence of damage of elements and the appearance of inelastic zones in the design process of fluctuations at each time step and to assess the dynamic behavior of the building.

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Rezaeian, Hooman, George Charles Clifton, and James B. P. Lim. "Compatibility Forces in Floor Diaphragms of Steel Braced Multi-Story Buildings." Key Engineering Materials 763 (February 2018): 310–19. http://dx.doi.org/10.4028/www.scientific.net/kem.763.310.

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Floors have a key role in the seismic behaviour of structures, especially in multi-story buildings. The in-plane behaviour of a floor system influences the seismic response of the structure significantly and affects the distribution of lateral forces between seismic resisting systems and over the height of the structure. In buildings where the seismic resisting systems are in the same location in plan on each floor over the height of the building, inertial and displacement compatibility shear forces are the principal shear forces generated at the interface between the floor system and the seismic-resisting system. These two are called interface diaphragm forces. These interface forces must be transferred into the appropriate lateral load resisting system and the interface must be well designed and detailed. Determination of the magnitude of the interface loads on concrete diaphragms are not well understood and still a matter of debate. There is no consensus of a design procedure for determining the diaphragm actions and distribution into the seismic resisting systems. In this paper, interface forces generated in floor diaphragms by asymmetrical actions of the braced framing system on each side of the building in the direction of analysis have been investigated. A numerical study using Numerical Integration Time History Analysis (NITH), has been undertaken to evaluate the interface forces of concrete floor diaphragms in a 12-story braced steel building. The results of nonlinear time history analyses using ground motion records from three different earthquakes are presented.

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Yan, Xian Li, Qing Ning Li, Chang Gao, and Li Ying Wang. "Research on Dynamic Performance of Concrete-Filled Steel Tubular Trussed Arch Bridge under Earthquake." Advanced Materials Research 368-373 (October 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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12

Humar, JagMohan, Soheil Yavari, and Murat Saatcioglu. "Design for forces induced by seismic torsion." Canadian Journal of Civil Engineering 30, no. 2 (April 1, 2003): 328–37. http://dx.doi.org/10.1139/l02-029.

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Eccentricities between the centres of rigidity and centres of mass in a building cause torsional motion during an earthquake. Seismic torsion leads to increased displacement at the extremes of the building and may cause distress in the lateral load-resisting elements located at the edges, particularly in buildings that are torsionally flexible. For an equivalent static load method of design against torsion, the 1995 National Building Code of Canada specifies values of the eccentricity of points through which the inertia forces of an earthquake should be applied. In general, the code requirements are quite conservative. They do not place any restriction on the torsional flexibility, however. New proposals for 2005 edition of the code which simplify the design eccentricity expressions and remove some of the unnecessary conservatism are described. The new proposals will require that a dynamic analysis method of design be used when the torsional flexibility of the building is large. Results of analytical studies, which show that the new proposals would lead to satisfactory design, are presented.Key words: torsional response to earthquake, natural torsion, accidental torsion, design for torsion, National Building Code of Canada, interdependence of strength and stiffness.

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13

Singh, M. P., L. M. Moreschi, L. E. Suárez, and E. E. Matheu. "Seismic Design Forces. I: Rigid Nonstructural Components." Journal of Structural Engineering 132, no. 10 (October 2006): 1524–32. http://dx.doi.org/10.1061/(asce)0733-9445(2006)132:10(1524).

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Singh, M. P., L. M. Moreschi, L. E. Suárez, and E. E. Matheu. "Seismic Design Forces. II: Flexible Nonstructural Components." Journal of Structural Engineering 132, no. 10 (October 2006): 1533–42. http://dx.doi.org/10.1061/(asce)0733-9445(2006)132:10(1533).

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15

Quimby, T. Bartlett. "Seismic Forces in Spherical Domes: Membrane Solution." Journal of Engineering Mechanics 121, no. 11 (November 1995): 1272–75. http://dx.doi.org/10.1061/(asce)0733-9399(1995)121:11(1272).

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16

Kaynia, Amir M., and Saeed Mahzooni. "Forces in Pile Foundations under Seismic Loading." Journal of Engineering Mechanics 122, no. 1 (January 1996): 46–53. http://dx.doi.org/10.1061/(asce)0733-9399(1996)122:1(46).

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17

Palaskas, M. N., Limin He, and Michael Chegini. "Vertical Seismic Forces on Elevated Concrete Slabs." Practice Periodical on Structural Design and Construction 1, no. 3 (August 1996): 88–90. http://dx.doi.org/10.1061/(asce)1084-0680(1996)1:3(88).

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18

Haroun, Medhat A., and Rong Chang. "Internal Seismic Forces on Submerged Oil Tanks." Journal of Waterway, Port, Coastal, and Ocean Engineering 111, no. 6 (November 1985): 1000–1008. http://dx.doi.org/10.1061/(asce)0733-950x(1985)111:6(1000).

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19

Heidebrecht, A. C. "Insights and challenges associated with determining seismic design forces in a loading code." Bulletin of the New Zealand Society for Earthquake Engineering 28, no. 3 (September 30, 1995): 224–46. http://dx.doi.org/10.5459/bnzsee.28.3.224-246.

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This paper presents and discusses a number of important topics which affect the determination of seismic design forces in a loading code. These range broadly from seismic hazard through to design philosophy and include the following aspects: influence of uncertainty in determining seismic hazard, seismic hazard parameters, site effects, probability level of design ground motions, role of deformations in seismic design, performance expectations and level of protection. The discussion makes frequent reference to the seismic provisions of both the National Building Code of Canada (1995) and the New Zealand Loading Standard (1992). Also, comparisons are made of seismic hazard and seismic design forces for several Canadian and New Zealand cities.

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Ning, Hao, Xiao Yin Lv, and Yi Jun Wang. "Research on Longitudinal Seismic Calculation Theory of Single-Story Factory Building." Applied Mechanics and Materials 166-169 (May 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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Indulkar, Nitin, Prof A. N. Humnabad, and Prof Dr Navnath V. Khadake. "Comparative Study of Seismic analysis of Bridge Substructure in different Seismic Zones as per IRC Guidelines." International Journal for Research in Applied Science and Engineering Technology 10, no. 5 (May 31, 2022): 3551–57. http://dx.doi.org/10.22214/ijraset.2022.43016.

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Abstract: The capacity design philosophy has currently become design norm for the seismic design of structural systems. it is necessary to assess the overstrength capacity of piers before proceeding with the design of the foundation and superstructure. This paper is devoted to developing deterministic procedures for the seismic analysis of substructure and foundation. Therefore, a moment-curvature approach is analysed. A parametric study is then conducted to investigate the factors that causes the seismic forces in the system. A simplified analysis methodology is put forward based on IRC SP 114; 2018. It is applicable for seismic design of bridges with a design service life of 100 years, considering Design Basis Earthquake (DBE). It has covered the seismic map and spectral acceleration graphs as specified in IS: 1893-Part-I- 2016. It also adopts the method prescribed for evaluation of liquefaction possibility, as specified in IS: 1893-Part-I- 2016. For the evaluation of seismic forces, Elastic Seismic Acceleration method, Elastic Response Spectrum method and Linear Time History method are specified. The IRC Guidelines describe the various types of special investigations to be carried out for bridges to be constructed in near field zones, skew, and curved bridges and so on. For loads and load combinations, IRC 6-2017 provides the guidelines and specifications. Objective of this code is to provide common procedure for design of bridges. It deals with the various loads such as vehicular loads, braking forces, wind load, water current forces and their combinations. Keywords: Seismic design of Bridge Substructure, IRC guidelines, Seismic design, Seismic analysis, seismic zones.

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Garipov, A. I., and P. A. Pyatkin. "Seismic analysis method of steel structures connections." Вестник гражданских инженеров 17, no. 2 (2020): 51–59. http://dx.doi.org/10.23968/1999-5571-2020-17-2-51-59.

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The article presents a technique of calculating steel structures connections taking into consideration the results of seismic analysis of steel structure carried out by linear spectral method. This technique allows reaching the equilibrium of forces and moments applied to the connection, wherein extreme internal forces’ values received correspond to the internal forces’ values obtained according to the currently valid acting construction codes.

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Patil, Abhishek K., Adarsh P. Solanke, Kuldeep R. Dabhekar, Isha P. Khedikar, Rahul Agrawal, Pratik P. Rajput, and Pranav V. Chavan. "Comparative Analysis of Structure with and without Seismic Load." IOP Conference Series: Materials Science and Engineering 1197, no. 1 (November 1, 2021): 012028. http://dx.doi.org/10.1088/1757-899x/1197/1/012028.

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Abstract Engineers are mostly adopting complex non-linear methods to research multi-storey residential apartment structure to withstand earthquake forces. This paper uses much simpler Equivalent Static method to analyse G+5 storey structure to repel earthquake forces using Staad pro software. The seismic analysis is further compared with non-seismic analysis of an equivalent structure using dead load + super load combination. it had been observed that the seismic results obtained consisted of significantly increased maximum moments and shear forces than the non-seismic analysis From past earthquakes it is proved that many of structure ar completely or partly broken because of earthquake. So, it’s a necessity to figure out unstable responses of such structures. The main aim of the present work is to make a comparative study of seismic and non-Seismic structure. The analysis was performed as per the specification of IS codes IS 1893, IS 875, IS 456:2000.

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LIVAOGLU, RAMAZAN, ALPER TURAN, M. HESHAM EL NAGGAR, and ADEM DOGANGUN. "THE NUMERICAL AND EMPIRICAL EVALUATION OF STRUCTURAL PERFORMANCE OF ELEVATED TANKS CONSIDERING SOIL–STRUCTURE INTERACTION EFFECTS." Journal of Earthquake and Tsunami 06, no. 02 (June 2012): 1250008. http://dx.doi.org/10.1142/s179343111250008x.

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Water tanks are an essential lifeline whose continuing availability and serviceability immediately after earthquake events are crucial for providing undisrupted emergency services. Their seismic performance is, therefore, of paramount importance. The seismic response of an elevated liquid tank situated on a soft soil deposit was studied by means of field vibration tests and numerical simulations. The ambient and forced vibration tests were conducted to identify the soil–structure interaction (SSI) effects on the small strain dynamic behavior of the structure. A series of time domain numerical analyses were performed to evaluate the seismic performance of these structures from a performance based design point of view. The results showed that consideration of SSI increased the displacement demand significantly. Thus, the calculated maximum displacement demand for supporting frame components of the tank may be underestimated significantly when the SSI effects are neglected. In addition, the seismic induced shear forces considering SSI effects were much smaller than the seismic shear forces for the fixed based case. For some soil types, the effect of this reduction on the overall response may become more prominent than the structural ductility mechanism. This resulted in the failure mechanism being initiated by a coupled compression — bending moment effect, rather than shear failure. Finally, the sloshing response is significantly increased due to the SSI.

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Goel, Rakesh K., and Anil K. Chopra. "Extension of Modal Pushover Analysis to Compute Member Forces." Earthquake Spectra 21, no. 1 (February 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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Poletto, Flavio. "Energy balance of a drill-bit seismic source, part 2: Drill-bit versus conventional seismic sources." GEOPHYSICS 70, no. 2 (March 2005): T29—T44. http://dx.doi.org/10.1190/1.1897039.

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The radiation properties of a downhole drill-bit seismic source are related to the amplitude and frequency of the forces exerted by the working bit. The main vibration modes of roller-cone and polycrystalline diamond compact (PDC) bits are investigated under different drilling conditions. The analysis includes vibrations produced by teeth indention, multilobed patterns, bouncing with periodic and random effects, single-cutter forces, stick-slip and whirling effects, mud-pressure modulation forces, and bit wear. Drill-bit radiation properties are calculated using the results obtained in part 1 of this paper and are numerically compared to the radiation of conventional vertical seismic profiling (VSP) sources.

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CHANDRASEKARAN, S., A. K. JAIN, and N. R. CHANDAK. "SEISMIC ANALYSIS OF OFFSHORE TRIANGULAR TENSION LEG PLATFORMS." International Journal of Structural Stability and Dynamics 06, no. 01 (March 2006): 97–120. http://dx.doi.org/10.1142/s0219455406001848.

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Oil and gas production from deep-water offshore fields represent a major structural engineering challenge for the industry. The tension leg platform (TLP) is a well-established concept for deep-water oil exploration. It is necessary to design an offshore TLP such that it can respond to moderate environmental loads without damage, and is capable of resisting severe environmental loads without seriously endangering the occupants. Seismic analysis of triangular TLP under moderate regular waves is investigated. The analysis considers nonlinearities due to the change in tether tension and nonlinear hydrodynamic drag forces. The coupled response of TLP under moderate regular sea waves due to change in initial pretension in the tethers caused by seismic forces (vertical direction) is then investigated. Seismic forces are imposed at the bottom of each tether as axial forces. The tether tension becomes unbalanced when the hull is under offset position. The vertical component of seismic force is an important item to take into consideration, because it is directly superposed to pretension of tethers. The change in initial pretension due to the vertical component of the earthquake affects the response of the triangular TLP in degrees-of-freedom experiencing such forces. The tether tension varies nonlinearly when the platform is subjected to seismic forces caused by the El Centro earthquake and artificially generated earthquake using Kanai–Tajimi's power spectrum. The response due to earthquakes varies with the intensity of the input ground motion. The seismic response of the triangular TLP exhibits nonlinear behavior in the presence of waves and it is non-proportionately influenced by the wave period and the wave height.

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Tso, W. K., A. Ghobarah, and S. K. Yee. "Seismic design forces for cylindrical tanks on ground." Canadian Journal of Civil Engineering 12, no. 1 (March 1, 1985): 12–23. http://dx.doi.org/10.1139/l85-002.

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A study is made on the hydrodynamic effect caused by seismic ground motions on the design of cylindrical on-ground liquid-storage tanks. The current techniques for determining the design base shear and overturning moment of the tank are reviewed, first treating the tank wall as rigid and then including the wall flexibility effect. By means of examples, these calculations are compared with those suggested by the National Building Code of Canada (NBCC). In addition, theoretically predicted values are compared with experimental data.It was found that in the case of tanks of high height to radius ratio and small wall thickness to radius ratio, the interaction of the fluid and wall flexibility can cause responses as high as two to three times those calculated based on rigid tank wall assumptions. The range of tank geometries under which the tank can be considered rigid is given. It is shown that the NBCC formula to establish seismic loads for tanks on ground is in general conservative, provided the acceleration ratio in the NBCC formulae takes on the value of maximum peak ground acceleration of the site. Key words: seismic, earthquake, hydrodynamic force, response, cylindrical tanks, design code.

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Xu, Yang, Jun Zhao, Xiao Yan Xu, and Dan Zhu. "Response Spectrum Analysis of a Large-Span Hangar Subjected to Multi-Dimensional Seismic Inputs." Advanced Materials Research 639-640 (January 2013): 906–10. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.906.

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The multi-dimensional seismic response of a single-span hangar was studied by response spectrum analysis method. The lateral displacements of the structure, forces of its supporting columns and its roof structure were calculated and compared with each other for cases of one-, two- and three-dimensional (1D, 2D and 3D) seismic inputs. The results show that, compared with the case of 1D earthquake input, the effects of horizontally 2D earthquake inputs on the internal forces and displacements of its supporting columns in the primary direction of input are obvious when it is along the symmetrical axis of the hangar and their effects in the secondary direction of input are even more important which results in great increases of the internal forces and displacements in that direction. The vertical seismic input has almost no effect on the internal forces and displacements of columns. The internal forces in different parts of the roof structure are controlled by horizontal or vertical inputs, respectively, and, compared with those from horizontally or vertically 1D inputs, the responses from 3D inputs are increased and the effects should be considered in seismic design.

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Chrysostomou, C. Z., N. Kyriakides, A. J. Kappos, L. Kouris, E. Georgiou, and M. Millis. "Seismic Retrofitting and Health Monitoring of School Buildings of Cyprus." Open Construction and Building Technology Journal 7, no. 1 (December 27, 2013): 208–20. http://dx.doi.org/10.2174/1874836801307010208.

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The vulnerability of existing buildings to seismic forces and their retrofitting is an international problem. The majority of structures in seismic-prone areas worldwide are structures that have been designed either without the consideration of seismic forces, or with previous codes of practice specifying lower levels of seismic forces. In Cyprus, after the three earthquakes that occurred in 1995, 1996, and 1999, the Cyprus State, acting in a pioneering way internationally, has decided the seismic retrofitting of all school buildings, taking into account the sensitivity of the society towards these structures, which house the future generation of the society. In this paper the overall assessment methodology is presented, along with details of the over 10 year ongoing retrofitting program of the school buildings of Cyprus, with emphasis on the description of the program and the development of a wireless monitoring system. In addition, mathematical models of selected school buildings are presented and comparison is made with in-situ measurement.

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Humar, J., M. Mahgoub, and M. Ghorbanie-Asl. "Effect of second-order forces on seismic response." Canadian Journal of Civil Engineering 33, no. 6 (June 1, 2006): 692–706. http://dx.doi.org/10.1139/l05-119.

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In a building structure subjected to seismic forces, the gravity loads acting through the lateral displacements lead to additional shears and moments. This is generally referred to as the P–Δ effect; it tends to reduce the capacity of the structure to resist the seismic forces and may lead to instability. It has been suggested that an increase in structural strength, in stiffness, or in both would mitigate the P–Δ effect and ensure stability of the structure. It is shown here that instability results when the P–Δ effect causes the stiffness of the structure to become negative in the post-yield range, in which case increasing the strength, the stiffness, or both does not ensure stability. In a single-storey structure, stability can be ensured if there is sufficient strain hardening that the post-yield stiffness is positive even in the presence of the P–Δ effect. For a multistorey building the vulnerability of the structure to P–Δ instability can be judged by obtaining a pushover curve. It is shown that as long as the maximum displacement produced by the design earthquake lies in the region of positive slope of the pushover curve, the structure will remain stable.Key words: seismic response, P–Δ effect, dynamic instability, stability coefficient, amplification factor, pushover analysis, nonlinear analysis.

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Bosco, M., A. Ghersi, E. M. Marino, and P. P. Rossi. "A Capacity Design Procedure for Columns of Steel Structures with Diagonals Braces." Open Construction and Building Technology Journal 8, no. 1 (December 31, 2014): 196–207. http://dx.doi.org/10.2174/1874836801408010196.

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According to modern seismic codes, in concentrically braced frames the seismic input energy should be dissipated by means of the hysteretic behaviour of braces while all the other members (i.e. beams and columns) have to remain elastic. Accordingly, the design internal forces of braces are determined in these codes by elastic analysis of the structure subjected to seismic forces obtained by the design spectrum. The internal forces of the non-dissipative members, instead, are calculated by means of specified rules for the application of capacity design principles. According to some recent numerical analyses, the yielding or buckling of columns may take place before braces achieve their axial deformation capacity. This paper investigates the reasons of this unsatisfactory behaviour and proposes technological suggestions and a design procedure to improve the seismic performance of columns of building structures with diagonal braces.

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Xiao, Jie Ling, Xian Kui Wei, Ping Wang, and 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 (November 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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Abovyan, Avetik. "Simulating seismic impacts using vibrating machines." MATEC Web of Conferences 251 (2018): 04027. http://dx.doi.org/10.1051/matecconf/201825104027.

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The article presents a method to reproduce seismic impacts on structures according to an accelerogram of an earthquake. Three powerful vibrating machines have to be installed on different floors of the structure, where oscillation characteristics are selected based on the spectrum of acceleration of the earthquake and so that the values of the inertial forces arising in the structure during their operation are equal to the true values of seismic forces which arise during the same earthquake. Key words: vibrating machine, eccentric, accelerogram, structure, model.

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Yang, Xi Wen, and Zi Bao Lian. "Seismic Displacements Reduction for a Long-Span Cable-Stayed Bridge." Advanced Materials Research 255-260 (May 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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Zdravkovic, Slavko, Biljana Mladenovic, and Dragan Zlatkov. "Seismic hazard in the design of oil and gas pipelines." Facta universitatis - series: Architecture and Civil Engineering 9, no. 2 (2011): 231–40. http://dx.doi.org/10.2298/fuace1102231z.

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Criteria that are adopted in earthquake resistant design of pipelines and gas lines have to take into account seismic movements and seismic generated forces that are of significantly high probability level of appearance along the length of pipeline. A choice of criteria has to include an acceptable level of seismic hazard, while design criteria should be calculated. Seismic hazard is defined as a part of natural hazard and means probability of appearance of earthquake of corresponding characteristics in certain time and place. For design needs and calculation of influences caused by seismic forces the most important is seismic hazard of maximal horizontal acceleration due to ground vibration during earthquake. The methodology of seismic hazard calculation as base for micro seismic zoning is presented in the paper. It is shown calculation of seismic hazard of maximal horizontal acceleration due to ground vibration that is applied for 985 points at the territory of Republic of Serbia, based on which maps for return periods of 50 and 200 years are drawn.

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Sharma, S., and A. Prashant. "Two mechanisms in reinforced soil structures subjected to seismic forces." IOP Conference Series: Materials Science and Engineering 1260, no. 1 (October 1, 2022): 012049. http://dx.doi.org/10.1088/1757-899x/1260/1/012049.

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Abstract Internal stability analysis of reinforced soil structures assumes different failure surface generally applicable to geosynthetic reinforcement and steel reinforcement, considering those as extensible and inextensible, respectively. The same assumption is applicable to seismic design too. However, a wall reinforced with geosynthetic reinforcement of high stiffness or small spacing and comparatively rigid facia can depict behaviour similar to walls reinforced with inextensible reinforcement. It is imperative to understand this behaviour and see applicability of different mechanisms depending on relative extensibility of reinforcements during seismic loading. A 2D Finite Element model of a wrap-around reinforced soil structure is developed in OpenSees and subjected to seismic forces. Analysis is focused on the development of failure plane, defined on the basis of the locus of maximum reinforcement forces. The reinforcements with low stiffness in general showed a failure plane that follows Rankine’s active condition and with relatively high stiffness it showed roughly vertical failure mechanism. The locus of maximum reinforcement forces was also observed to be coincident with the zone of localized shear strains. These observations are useful in developing guidelines for safe and economical seismic design of reinforced soil structures.

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Son, Kwang Ik, Byung Seung Kong, Won Suk Jang, Hee Joong Kim, and Hack Soo Lee. "Probabilistic Approach for Cost Optimization of Structural Materials Using Plastic Hinge Mechanism." Advanced Materials Research 538-541 (June 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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Chernov, Yu T., and J. Qbaily. "Accounting for horizontal torsional vibrations of foundations when calculating seismic load." Bulletin of Science and Research Center “Stroitelstvo” 31, no. 4 (December 22, 2021): 66–78. http://dx.doi.org/10.37538/2224-9494-2021-4(31)-66-78.

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The article presents a method for calculating in-plane vibrations of building structures under seismic load taking into account the possibility of foundation displacement, which is similar to horizontal torsional vibrations when calculating earthquake forces. The method is illustrated by the structural design of a seven-storey tower-like building with a massive foundation. We develop transfer functions for a massive rigid body, which are subsequently used for calculating the response of the foundation subject to base shears and moments applied to the outer plane of the foundation under seismic forces. The structural calculations conducted for ductile structures with the first frequency of ~2.4 Hz and for more rigid structures with the first frequency of 7.1 Hz showed that, depending on the building stiffness, reduced seismic forces increase by 1.5–2 times. According to the results obtained, when designing structures in areas of high seismic hazard, account should be taken of possible foundation flexibility effects depending on different types of soil and structural solutions of particular buildings.

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Vasudev, Deepali. "Comparative Study on Seismic Analysis of Multi Storied RC Framed Structure with and without Diaphragm Discontinuity." International Journal for Research in Applied Science and Engineering Technology 9, no. 10 (October 31, 2021): 657–62. http://dx.doi.org/10.22214/ijraset.2021.38474.

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Abstract: Any Structure that is designed in today’s world has to be designed not only for aesthetics but also for stability. These days high rise multi storied structures are quiet prominent. These types of structures, should not only be designed for aesthetic point of view but also must be designed to resist earthquake forces which are subjected on these structures. These earthquake forces acting on the structures are also known as seismic forces. Due to architectural purposes, some buildings, have openings, provided in them, this creates structural discontinuities in the building. These openings or discontinuities can change the load transfer path of the structures which may cause significant change in the building behavior, under the application of the seismic forces. In this paper pushover analysis is carried out to study the behavior of the building in case of architectural opening for staircase or cut outs etc which results in discontinuity in the structure. Keywords: Diaphragm, Discontinuity, ETABS, Pushover Analysis, Seismic

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Zubrickiy, Maksim, Oleg Ushakov, and Linar Sabitov. "Account for the contribution of higher vibration modes under seismic resistance estimation of system with elastomeric supports by nonlinear static method." Construction and Architecture 8, no. 1 (February 4, 2020): 59–66. http://dx.doi.org/10.29039/2308-0191-2020-8-1-59-66.

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The article presents higher vibration modes accounting method to evaluate system seismic resistance by nonlinear static method. As part of the study, in order to verify the proposed method for finding the inertial forces modified system series of dynamic and static calculations was performed. Proposed inertial forces modified system can be applied for seismic resistance estimation of system with elastomeric supports. The results difference varies within 12%.

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Esinovsky, Victor A., Mikhail P. Sainov, Boris A. Zaitsev, and Sergey A. Filippov. "SEISMIC STABILITY OF THE MOORING WALL ACCORDING TO THE RESULTS OF NUMERICAL SIMULATION." Stroitel stvo nauka i obrazovanie [Construction Science and Education], no. 4 (2019): 2. http://dx.doi.org/10.22227/10.22227/2305-5502.2018.4.2.

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Introduction. New building codes provide for a significant increase in the magnitude of seismic loads that should be perceived by hydraulic structures. In this regard, even in areas with low seismic activity, there may be a problem of ensuring the seismic stability of hydraulic structures. This is particularly acute in berthing facilities. As a rule, they are not so massive to withstand seismic loads. The issue of seismic stability of berthing facilities has not yet been properly considered. The results of numerical simulation of the seismic stability of the mooring-dividing wall during a 7-point earthquake are considered. A structure about 24 m high located on a non-rock base was investigated. Materials and methods. The seismic stability of the mooring structure was estimated by calculating its stress-strain state under the action of seismic forces. Calculations were carried out by the finite element method. Seismic loads on the structure were determined in two ways — by linear-spectral theory and by dynamic theory. For the calculation of seismic loads, 30 lower frequencies and the natural mode of the structure were determined together with an array of its base. When calculating according to the dynamic theory, the seismic effect was specified in the form of an accelerogram adopted for similar conditions. The direction of seismic impact was assumed horizontal. Results. According to the dynamic theory, seismic loads turned out to be lower than according to linear-spectral theory. However, the results of the calculation of the stress-strain state of the mooring structure were close. It was found that the seismic forces on the mooring wall will reach about a quarter of the weight of the structure. Under the influence of such forces, the mooring wall will lose its stability. Conclusions. To ensure seismic stability, it is recommended to combine the mooring wall and the base plate into a single monolithic structure, as well as to strengthen the lower part of the structure and facilitate the upper one.

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Vandanapu, Swamy Nadh, and Muthumani Krishnamurthy. "Seismic Performance of Lightweight Concrete Structures." Advances in Civil Engineering 2018 (2018): 1–6. http://dx.doi.org/10.1155/2018/2105784.

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Concrete structures are prone to earthquake due to mass of the structures. The primary use of structural lightweight concrete (SLWC) is to reduce the dead load of a concrete structure, which allows the structural designer to reduce the size of the structural members like beam, column, and footings which results in reduction of earthquake forces on the structure. This paper attempts to predict the seismic response of a six-storied reinforced concrete frame with the use of lightweight concrete. A well-designed six-storey example is taken for study. The structure is modelled with standard software, and analysis is carried out with normal weight and lightweight concrete. Bending moments and shear forces are considered for both NWC and LWC, and it is observed that bending moments and shear forces are reduced to 15 and 20 percent, respectively, in LWC. The density difference observed was 28% lower when compared NWC to LWC. Assuming that the section and reinforcements are not revised due to use of LWC, one can expect large margin over and above MCE (maximum considered earthquake; IS 1893-2016), which is a desirable seismic resistance feature in important structures.

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Hernández-Martínez, Alejandro, Andrés E. Ortíz-Vargas, Adrián D. García-Soto, Jesús G. Valdés-Vázquez, and Mabel Mendoza-Pérez. "Influence of Seismic Behavior Factor on the Design of Building Structures for Low Seismic Demands Regions." Open Civil Engineering Journal 9, no. 1 (May 28, 2015): 274–80. http://dx.doi.org/10.2174/1874149501509010274.

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The use of reduced seismic forces obtained from elastic response spectra analysis is a common practice for structural design purposes. This procedure is used: (a) To take advantage of the nonlinear behavior of the structural elements that conform the entire structure, and (b) To reduce the initial cost of the construction, allowing certain degree of damage if a severe earthquake occurs, but trying to avoid collapse with good structural design and construction detailing. In this paper, structural analyses were performed using several seismic reduction coefficients and the considered structures were designed for low seismic design regions according to the Mexico construction codes for both, serviceability limit states and ultimate limit states. Results show that the final design is strongly dependent on allowed interstory drift, associated to lateral displacements. Results also showed that, reducing significantly the seismic forces is not directly associated with a reduction in the initial cost of the structure, i.e., the final design for different seismic behavior factor may have similar seismic vulnerability.

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ABE, Junichi, Hiroyuki SUGIMOTO, and Tadatomo WATANABE. "A STUDY ON CALCULATION OF SEISMIC DSIGN FORCES FOR STRUCTURES CONSIDERING THEIR SEISMIC RISKS." STRUCTURAL ENGINEERING / EARTHQUAKE ENGINEERING 25, no. 2 (2008): 75s—90s. http://dx.doi.org/10.2208/jsceseee.25.75s.

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ABE, Junichi, Hiroyuki SUGIMOTO, and Tadatomo WATANABE. "A STUDY ON CALCULATION OF SEISMIC DESIGN FORCES FOR STRUCTURES CONSIDERING THEIR SEISMIC RISKS." Doboku Gakkai Ronbunshuu A 63, no. 4 (2007): 780–94. http://dx.doi.org/10.2208/jsceja.63.780.

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Shingu, Kiyoshi, and Kinya Fukushima. "Seismic Isolation and Fuzzy Vibration Control of Shell Structure Subjected to Vertical Seismic Forces." Transactions of the Japan Society of Mechanical Engineers Series C 60, no. 577 (1994): 2999–3005. http://dx.doi.org/10.1299/kikaic.60.2999.

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Chen, Bai Ben, Zhong Ren Feng, and Xiong Jiang Wang. "Analysis for Influence of Structural System on Nonlinear Seismic Response of Cable-Stayed Bridge." Advanced Materials Research 1065-1069 (December 2014): 856–59. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.856.

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For different structural system of cable-stayed bridge, the dynamic characteristics have obvious difference under seismic load. Dynamic time-history analysis of earthquake was applied, and the EI Centero seismic wave with modified peak acceleration was chose as the earthquake acceleration time-history input. As Jiangsu Siyang special-shaped single tower cable-stayed bridge for engineering background, considering geometric nonlinear of structure, the differences of dynamic characteristics of cable-stayed bridge structures were gained under two different situations. The single longitudinal seismic ground motion was chose under the first situation, while the longitudinal, lateral, and vertical seismic ground motion are introduced. For floating system, the displacements are the largest and the inner forces are the smallest. For rigid frame system, the displacements are the smallest and the inner forces are the largest. The others are not much difference. Comprehensively, semi-floating system has better performance under seismic load.

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La Mendola, Lidia, Maurizio Papia, and Gaetano Zingone. "Stability of Masonry Walls Subjected to Seismic Transverse Forces." Journal of Structural Engineering 121, no. 11 (November 1995): 1581–87. http://dx.doi.org/10.1061/(asce)0733-9445(1995)121:11(1581).

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Rutenberg, Avigdor. "Seismic shear forces on RC walls: review and bibliography." Bulletin of Earthquake Engineering 11, no. 5 (May 30, 2013): 1727–51. http://dx.doi.org/10.1007/s10518-013-9464-1.

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Journal articles on the topic 'Seismic forces'

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