Transcript Modesto Junior College Science Community Center Design Challenges  Floor Vibration Criteria  Telescope Vibration Criteria  Horizontal Drift Joint  Spiral Stairs  Steel Subcontractor.

Modesto Junior College
Science Community Center
Design Challenges
 Floor Vibration Criteria
 Telescope Vibration Criteria
 Horizontal Drift Joint
 Spiral Stairs
 Steel Subcontractor – Walked Away
 Moment Frame – Grade Beam Interface
 Planetarium Door Widening
Floor Vibration Criteria
 Lab Consultant:
 W3 x 18 with 4 ½” normal weight concrete over the top of flutes;
total thickness = 7 ½”.
 Vibration Criteria was Excessive – Added an additional $1,000,000 in
steel floor beam cost to the project – $500,000 per floor.
 Compromise Solution – District not having vibration issues in current
facility:
 Floor Beams:
Design for 125 psf Live Load, Non-reducible
Limit deflection to:
L/240 DL + LL
L/360 LL Only
Design floor beams as “non-composite” then install Nelson studs @ 12”
oc.
Foundation Model:
Design for 80 psf Live Load (reducible) & 20 psf partition load
(Designs like this give engineers a bad name!)





Telescope Vibration Criteria
Telescope Independent Space Frame
Horizontal Drift Joint
Spiral Stairs
Steel Subcontractor Disappeared!
Total number of
subcontractors on the
project =63
Number of
subcontractors that
filed for bankruptcy
during construction
of the Science
Community Center
= 33
Impact of steel
subcontractor going
away:
$2.4 million
4 ½ month project
delay
Steel pieces
scattered across
the project site.
Moment Frame Column Base
Planetarium “Door Widening”