Question

1. The structure shown below has a special moment resisting moment frame for a lateral force resisting system. It is carrying the load of emergency generator. The soil profile is Site Class D. Based on the USGS map, spectral response acceleration parameters, Ss and S1 are 2.3g and 0.8g respectively. The weight of rigid floor is 15 kips. The emergency generator weighing 35 kips is located on the center of the rigid floor. (20 points) 1) Find the period of structure using the stiffness of the sections shown. Do not use approximate period method. (10 points) 2) Determine seismic base shear. (10 points) 11' Emergency Generator 35 kips 11' Bottom of the column is fixed against the translation and rotation. Rigid Floor Top of the column is free to translate in lateral direction, however, it is fixed against rotation Total weight of the rigid floor is 15 kips W 12x72 each column

Answer 1

Solūlion: Given that The soil profile is site class D. USGS map Based on the Spectral response acceleratiers para melen, Ss 9.38 0.89 SI 15 kips. The weight of digid floor = The emergency generālos Weight 35 kips. (localed on the centre of the digid Floor.). The Lateral stiffness of the frame 1. 126 KL WEI 3 -H L3 24 E 1 _3 of H1QxT2 cation. EI is flexural vigiding Ix=597 in 4 EI - 29000 ksi 22X12 - CSScanned with CamScanner 2764".

KL ay x29000 x 597 (264)' Thie 99.58 Hlin → Time period! T = IT KL m= Total mass mass of Food + mass of generaloo 15 + 35 9 50 Eps 89.2 X12 m 0.13 kips s²lin ㅜ शा 0.13 T 0.475 sec CSScanned with CamScanner

Ss - 0.33 Si = 0.89 SITE class 'D' Bose Shear V= ( sh SIS Cs R Veing table 13.3.1 ASCE 7 R=8 Ic=1 Fo=1 from table 11.4.1, ASCE 7 from table 11.4.2, ASCE 7 + Ford = 1.7 Sms Fa Ss - 1 x8.39 8.39 → Smi Fv XS, 1.7 X0.89 SDS - = 1.369 27 / 3 Sms 27/33 x 2.3g CSScanned with CamScanner

= 1.538 Soi 3x Smi 8 x 1.36 .6 g = 0.90679 Ts Sos Sos 0.9067 1.53 0.59 sec TL TS , C (0.475 20:59) 1.53 (8/1) = 0.19125 Base Shear CS hl 0.19125 x 50 9.5625 tips V = 9.5625 tips CSScanned with CamScanner