鉛直荷重下単層ラチスドームの静的および動的応答における弾塑性挙動の比較 [in Japanese] COMPARISON STUDY OF ELASTO-PLASTIC BEHAVIOR ON STATIC AND DYNAMIC RESPONSES FOR SINGLE LAYER LATTICE DOMES UNDER VERTICAL LOADING [in Japanese]
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This paper focuses on the elasto - plastic behavior of static and dynamic responses for single layer lattice domes, which are subjected to vertical loads. The purpose is to make clear the relationship between seismic responses and static responses such as static absorbed energy properties after and before yielding, and to estimate bearable seismic levels with the information of static elasto - plastic behaviors. The two responses compared are shown in Fig. 14. The dimensions of both figures are equal in multiplying or dividing by circular frequency.<br> The single layer lattice domes are shown in Fig. 1. Half open angle of members and self-weight are adopted as numerical parameters as shown in Table 3. The static elasto - plastic behaviors are shown in Fig. 3. In the figure, The solid lines are the equivalent velocity of strain energies, the dotted and dashed lines are that of static absorbed energies and the dashed lines are that of potential energy performed by the product of self-weight and vertical displacements. These relationships obtained are simplified into bi-linear relationships as shown in Fig. 4 to obtain the static elasto - plastic property coefficient j. The obtained results of coefficient j are shown in Table 4.<br> Secondary, the dynamic elasto - plastic behaviors are estimated against 4 seismic waves of Fig. 5. The dynamic behavior obtained is the relationships between maximum ground acceleration PGA and strain energies. The obtained results are shown in Figs. 6-9 and simplified into bi-linear relationships to obtain the dynamic elasto - plastic property coefficient q, as shown in Fig. 14(b). The obtained results are shown in Table 5.<br> In comparing the two property coefficients j and q as shown in Fig. 10, BCJ wave is relatively large about the dynamic effect. On the contrary, El Centro wave is the smallest among the four waves. This reason is made clear in considering the input acceleration power history as shown in Fig. 11. BCJ wave of Fig. 11(a) has many peaks during the motions, but El Centro wave of Fig. 11(b) has a few peaks during the first half of motions. These strong characteristics of seismic waves can be considered with the input energy spectrum V<sub>E</sub> as shown in Fig. 12. Then the ratios q/j are compared with the ratios V<sub>E</sub>/S<sub>V</sub>. The ratio q/j decreases as the ratio V<sub>E</sub>/S<sub>V</sub> increases.<br> The Eqn. 5 is the regression formula obtained by the data distributed in the quadrangle of Fig. 13, expressed as dotted and dashed line in the figure. The PGA corresponding to the limit state deformations can be estimated with Eqns. 4 and 5. The predicted results are shown in Fig. 15 and Table 6.<br> The following conclusions are obtained in the present study: (1) The relationship of maximum earthquake input acceleration PGA and strain energies of domes shows bi-linear type such as the relationships of static absorbed energies and displacements. (2) In comparing the preceding two relationships as for dynamic and static responses, the change ratios among elastic and plastic ranges are dependent upon the seismic waves. The distribution tendencies are able to be explained with the information of input acceleration power history of seismic waves. (3) The ratios of dynamic property q against static property j becomes smaller, as the ratios of energy spectrum V<sub>E</sub> against velocity response spectrum S<sub>V</sub> becomes larger. (4) The present estimation method of PGA corresponding to limit state deformations shows a relatively good accuracy.
- Journal of Structural and Construction Engineering (Transactions of AIJ)
Journal of Structural and Construction Engineering (Transactions of AIJ) (747), 709-716, 2018-05
Architectural Institute of Japan