CE 5803Fall 2015Homework - 1Due to: October 13th, 2015

1. For the column shown in figure what is EI necessary to give the frequency equals to 3 Hz. Let the mass is 1.2 tons and l is 4 m.

2. Assume that we have a structure with a fixed base period 2.0 sec. on an isolation system with a period of 2 sec. Take the damping in the structure is 2% and that for the isolation system 10% and assume that the specified spectrum is a constant velocity spectrum of 600 mm/s at 5% damping.

A. Compute the displacements and base shear coefficients of the fixed base and isolated systems.

B. Now assume that the structure is completely rigid and the constant velocity spectrum is 500 mm/s. Compute the displacements and base shear coefficients of the fixed base and isolated systems.

Discuss the results of part a and b. Discuss also benefits and limitations of the isolation for a flexible (part a) and for a rigid (part b) structure.

Note: In case if you need a response spectrum use the one given below.

M

EIl

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