ARCH 2615-5615 Building Technology II: Structural Elements
Spring 2022
Jonathan Ochshorn
Practice problems for Prelim 1
In addition to multiple choice and true-false questions based on the various lectures, there will be problems worth 8 points each for column, beam, and girder design. Use the online calculators to solve these three problems. What follows are examples of such problems: note that the geometry is described, but not "drawn" as a section and framing plan. Feel free to draw such diagrams yourself if it helps!
Using online calculators, select the lightest "post and timber" interior second-floor column, based on the following specifications: 4-story building, so the column is supporting 2 floors and the roof; the typical column bay (spacing between columns) is 24 feet x 18 feet; the column "unbraced" height along both axes is 12 feet; dead load, D = 18 psf for all floors and roofs; live load, L = 40 psf; snow load, S = 45 psf; Lr = 30 psf; use live load reduction; account for wood's duration of load factor; and use Spruce-Pine-Fir No. 2.
a) 6x6; b) 10x10; c) 10x12; d) 12x12
Using online calculators, select the lightest interior beam, based on the following specifications: the beam's span = 18 feet; the spacing between beams = 8 feet; all loads can be assumed to be uniformly distributed on the beam; dead load, D = 18 psf; live load, L = 40 psf; use live load reduction; assume typical deflection criteria of L/240 (total load) and L/360 (live load); and use Spruce-Pine-Fir No. 2.
a) 4x16; b) 6x22; c) 6x24; d) 8x22
Using online calculators, select the lightest interior girder, based on the following specifications: the girder's span = 24 feet; the spacing between girders = 18 feet; all loads are transferred to the girder at its third-points; dead load, D = 18 psf; live load, L = 40 psf; use live load reduction; assume typical deflection criteria of L/240 (total load) and L/360 (live load); and use Spruce-Pine-Fir No. 2.
a) 18x24; b) 16x24; c) 14x24; d) 12x24
Solutions
Column design
Governing load calculator (newer version)
The governing load = 51 kips with Cd = 1.15 (Fig. 1)
Wood column calculator: Select 10x12 (Fig. 2)
Beam design
Wood beam design calculator: Select 6x22 (Fig. 3)
Girder design
Wood beam design calculator: Select 16x24 (Fig. 4)
Copyright
2021 J. Ochshorn. All rights reserved. First posted: 4 March 2021 | last updated: 17 February 2022
ARCH 2615-5615 Building Technology II: Structural Elements
Spring 2022
Jonathan Ochshorn
Practice problems for Prelim 1
In addition to multiple choice and true-false questions based on the various lectures, there will be problems worth 8 points each for column, beam, and girder design. Use the online calculators to solve these three problems. What follows are examples of such problems: note that the geometry is described, but not "drawn" as a section and framing plan. Feel free to draw such diagrams yourself if it helps!
Using online calculators, select the lightest "post and timber" interior second-floor column, based on the following specifications: 4-story building, so the column is supporting 2 floors and the roof; the typical column bay (spacing between columns) is 24 feet x 18 feet; the column "unbraced" height along both axes is 12 feet; dead load, D = 18 psf for all floors and roofs; live load, L = 40 psf; snow load, S = 45 psf; Lr = 30 psf; use live load reduction; account for wood's duration of load factor; and use Spruce-Pine-Fir No. 2.
a) 6x6; b) 10x10; c) 10x12; d) 12x12
Using online calculators, select the lightest interior beam, based on the following specifications: the beam's span = 18 feet; the spacing between beams = 8 feet; all loads can be assumed to be uniformly distributed on the beam; dead load, D = 18 psf; live load, L = 40 psf; use live load reduction; assume typical deflection criteria of L/240 (total load) and L/360 (live load); and use Spruce-Pine-Fir No. 2.
a) 4x16; b) 6x22; c) 6x24; d) 8x22
Using online calculators, select the lightest interior girder, based on the following specifications: the girder's span = 24 feet; the spacing between girders = 18 feet; all loads are transferred to the girder at its third-points; dead load, D = 18 psf; live load, L = 40 psf; use live load reduction; assume typical deflection criteria of L/240 (total load) and L/360 (live load); and use Spruce-Pine-Fir No. 2.
a) 18x24; b) 16x24; c) 14x24; d) 12x24
Solutions
Column design
Governing load calculator (newer version)
The governing load = 51 kips with Cd = 1.15 (Fig. 1)
Wood column calculator: Select 10x12 (Fig. 2)
Beam design
Wood beam design calculator: Select 6x22 (Fig. 3)
Girder design
Wood beam design calculator: Select 16x24 (Fig. 4)
Copyright
2021 J. Ochshorn. All rights reserved. First posted: 4 March 2021 | last updated: 17 February 2022