Modesto Junior CollegeScience Community Center

Design ChallengesFloor Vibration CriteriaTelescope Vibration CriteriaHorizontal Drift JointSpiral StairsSteel Subcontractor – Walked AwayMoment Frame – Grade Beam InterfacePlanetarium Door Widening

Floor Vibration CriteriaLab 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 million4 ½ month project

delaySteel pieces

scattered across the project site.

Moment Frame Column Base

Planetarium “Door Widening”