FACTS AND ASSUMPTIONS
IRP 1:
A flat roof design will be used in accordance with the university master plan
Roofing materials used include: 20 gauge metal decking, 2" fiberboard thermal insulation, a waterproof membrane, drop ceiling, suspended steel channel system, HVAC system, lighting components, and a roof decking
Floor materials used include 1.5" terrazzo tile, drop ceiling, suspended steel channel system, HVAC system, lighting components, and a floor decking
A slab of 3.5 inches of lightweight concrete will be used for the ground floor decking
Vulcraft was used to chose the roof and floor decking
Decks will be 3 eight ft spans at a length of 42 ft
The facility will include: dance floor/auditorium, stage, storage, and bathrooms
Beams and columns are wide flange and truss members are double angle
All columns are pinned at the foundation
All roof/floor beams and joists have simple connections
All truss connections are pinned
Parapet dead loads were calculated using ASCE C3.1-1a
Snow load for the New York area was found using ASCE Figure 7.2-1
Risk category III was used considering the building poses a high risk to human life in the event of failure (ASCE Table 1.5-1)
Exposure B was selected considering the mean roof height is less than 30 feet
Ground floor live loads were found using ASCE Figure 4.3-1
It is assumed that the snow load will be greater than 20 psf, thus the roof live load can be ignored
Assuming a Risk Category III, Exposure B, and a mean height of 20 ft, the wind loads can be calculated
IRP 2:
Self weight of roof joists RJ1 =15plf
Both roof trusses are identical due to symmetry
Roof truss has a height of 4 feet
Include truss member self weight in the dead load case in VA
Load case combinations 4 and 5 do not apply since they are not apart of the lateral load carrying system
Maximum Pu of a member (ie. Top Chord T5) is used to represent all members as the same Pu value (ie. Top Chords T1-8).
Pin-Pin Connection, so the effective length factor, K, equals 1.0
All truss members are equal leg double angles
The separation of the members is 3/8"
All beams are made from A36 Steel
Ae=0.75Ag
The truss may not exceed a snow load deflection greater than L/240
A maximum of 4 unique members can be included
The cost per pound of Steel is $0.50
The cost per truss node is $20
The cost per unique member Fabrication is $100
The cost per ton for Fabrication is $750
IPR 3:
Service load end reactions are applied from the beams and joists to the girders and then from the girders and beams to the leaning columns.
For lateral bracing members, assume the leaning columns are pinned at the base (foundation).
Governing LCC may change as you go down the load path.
Pass only service (unfactored) reactions down to the next member.
It is necessary to cope the flanges to facilitate connecting them into members
Nominal floor beam and girder depth should be at least 21 inches for making room for mechanical ducts.
For deflections, the member self-weight is not included.
Cambering can be used for dead load deflections only (total load criteria). Camber cannot be applied to live load deflections.
Loads are not factored when calculating deflections.
Select either of the two types of connections for beam to column/girder and use for FG1 to column connection.
Once the initial beams and girders are chosen, self-weight is included and load effects are recalculated.
Beams are continuously supported by the floor deck and have an unbraced length of zero feet (Lb= 0) due to spot welds to the deck along the length of the beam.
For girders, use an unbraced length equal to the beam spacing.
Column designs are pin-pin connections, so k=1.0