Non-Building Structures PDF

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Non-Building Structures

by: Engr. Tan...

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4.2. Non-Building Structures: CE 305 - Principles of Earthquake Engineering

Lesson 4.1: Non-Building Structures Non-Building Structures Non-building structures include all self-supporting structures other than building that carry gravity loads and resist the effects of earthquakes. Non-building structures shall be designed to provide the strength required to resist the displacements induced by minimum lateral forces specified in this section. Design shall conform to the applicable provisions of other section as modified by the provisions contained in Section 208.8. The weight W, for non-building structures shall include all dead loads as defined for buildings in Section 208.6.1. For purposes of calculating design seismic forces in non-building structures, W, shall also include all normal operating contents for items such as tanks, vessels, bins and piping.

Lateral force procedures for non-building structures with structural systems similar to buildings (those with structural systems which are listed in NSCP 2015 Table 208-11) shall be selected in accordance with the provisions of Section 208.4. There is an exception for non-building structures. Intermediate 1

moment-resisting frames (IMRF) may be used in Seismic Zone 4 in Occupancy Categories III and IV if: the structure is less than 15m height the value R used in reducing calculated member forces and moments does not exceed 2.8 Rigid structures (those with period T less than 0.06s) and their anchorages shall be designed for the lateral force obtained from Equation 208-24

V = 0.7C a IW The force V shall be distributed according to the distribution of mass and shall be assumed to act in any horizontal direction. Flat bottom tanks and or other tanks with supported bottoms, founded at or below grade, shall be designed to resist seismic forces calculated using the procedure in Section 208.9 for rigid structures considering the entire weight of the tank and its contents. The total design lateral seismic force Fp to be used for tanks shall be:

Fp = 4Ca I p Wp Non-building structures that are not covered by Section 208.8.3 and 208.8.4 shall be designed to resist design seismic forces not less than those determined in accordance with the provisions in Section 208.5 with the following additions and exceptions: 1. The factors R and Ωo shall be as set forth in Table 208-12. The total design base shear determined in accordance with Section 208.5.2 shall not be less than the following:

V

= 0.56Ca

IW Additionally, for Seismic Zone 4, the total base shear shall also not be less than the following:

V

=

R vI 1.6 ZN

W

Example 1 A non-building structure with a concrete intermediate moment-resisting frame (IMRF) supports some rigid aggregate storage bins. Weights W1 and W2 include the maximum normal operating weights of the storage bins and contents as well as the tributary frame weight. The following information is given:

Structure is located in Zone 4 Importance Factor = 1.0 Soil Profile Type D Seismic Source Type C Distance to Seismic Source = 5km T = 2.0s R = 2.80 Determine the following: 1. Design base shear, V 2. Vertical distribution of seismic forces Solution

Example 2 A rigid ore crushing equipment is supported by a massive concrete pedestal and seismic design forces are to be determined. The following information is given: Structure is located in Zone 4 Importance Factor = 1.0 Soil Profile Type B Seismic Source Type B Distance to Seismic Source = 5km T = 0.02s

Determine the following: 1. Design base shear, V 2. Vertical distribution of seismic forces Solution...