0.9D - + (Standard Basic Load Combination 7) Ev Eh These seismic load effects can be used to determine bolt shear, and tension, (where a negative Vu Tu value indicates tension). In the calculations below, the signs of and have been selected to result SDS Fp in the largest value of Similar calculations would be performed to determine the maximum Tu. compressive force Cu. = 1.2D + 0.2SDSD + U ρQE = = -2,405 lb Tu = = 4,204 lb Cu = = 3,346 lb Vu = 0.9D - 0.2SDSD + U ρQE = = 2,630 lb Tu = = -3,980 lb Cu = = 3,346 lb Vu The vibration isolator would be designed to resist these forces. 18.4.4.2 Proportioning and Details. In this example, there is no component or a support in the load path leading to the structure that undergoes ductile yielding at a load level less than the design strength of the corresponding anchor, so the anchors are designed to resist the load combinations considering in Ω0 accordance with Section 2.3.6. In the calculations below, the signs of and have been Standard SDS Fp selected to result in the largest value of The geometry of the vibration isolators are shown in Figure Tu. 18.4-4. By inspection, the load combination that results in net tension on the anchors governs. Applying the load combinations of Section 2.3.6, Load Combination 7, the vertical design tension force Standard is: = 0.9D + (Standard Basic Load Combination 7) U Ev Emh – = (Standard Eq. 12.4-7) Emh Ω0QE
0.9D - Ev + Eh (Standard Basic Load Combination 7) These seismic load effects can be used to determine bolt shear, Vu and tension, Tu (where a negative value indicates tension). In the calculations below, the signs of SDS and Fp have been selected to result in the largest value of Tu. Similar calculations would be performed to determine the maximum compressive force Cu. U = 1.2D + 0.2SDSD + ρQE Tu = = -2,405 lb Cu = = 4,204 lb Vu = = 3,346 lb U = 0.9D - 0.2SDSD + ρQE Tu = = 2,630 lb Cu = = -3,980 lb Vu = = 3,346 lb The vibration isolator would be designed to resist these forces. 18.4.4.2 Proportioning and Details. In this example, there is no component or a support in the load path leading to the structure that undergoes ductile yielding at a load level less than the design strength of the corresponding anchor, so the anchors are designed to resist the load combinations considering Ω0 in accordance with Standard Section 2.3.6. In the calculations below, the signs of SDS and Fp have been selected to result in the largest value of Tu. The geometry of the vibration isolators are shown in Figure 18.4-4. By inspection, the load combination that results in net tension on the anchors governs. Applying the load combinations of Standard Section 2.3.6, Load Combination 7, the vertical design tension force is: U = 0.9D – Ev + Emh (Standard Basic Load Combination 7) Emh = Ω0QE (Standard Eq. 12.4-7)
121715_DesignExamples_15-18.docx