COMPARISON STUDY OF ELASTO-PLASTIC BEHAVIOR ON STATIC AND DYNAMIC RESPONSES FOR SINGLE LAYER LATTICE DOMES UNDER VERTICAL LOADING

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. 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. 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. 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 VE as shown in Fig. 12. Then the ratios q/j are compared with the ratios VE/SV. The ratio q/j decreases as the ratio VE/SV increases. 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 cor