Skip to main content

Deflection: steel or wood

For EITHER steel or wood beams, a question that asks for the allowable deflection limit (maximum) for live loads only requires which of the following equations?
A. L/240
B. L/360
C. ∆ = 5wl⁴ / 384EI
D. ∆ = 5Wl³ / 384EI

AnswerB. L/360 or span in inches divided by 360.
ARE 4.0 exam prep: SS

Note on calculations: From posted discussions on AREforum, memorization of most equations is not advised. However, even when the equation may be available in in-exam reference, selection of the appropriate equation requires correct identification.

Comments

Try These Too!

Roof pitch

Which one of the following slopes in this illustration corresponds with an 8:12 pitch roof? A. 45° B. 36.87° C. 33.69° D. 26.57°

Roof diaphragm

From this plan of a simple wood frame structure (1-story height), what is the maximum chord force at the east and west edges of the roof diaphragm if 110 lbs/foot lateral wind load is exerted as shown? A. 18,340 lbs B. 367 lbs C. 3,670 lbs D. 4,600 lbs Answer D. 4,600 is correct. The lateral wind load here is similar to a uniform load acting on a simple beam turned on its side. To find the maximum chord force at the edges of the diaphragm, use the equation for maximum moment wl²/8 ÷ building plan depth. 110 lbs per foot x (100 ft)² / 8 ÷ 30ft = 4,583.33 ARE 4.0 exam prep: SS

Building Efficiency

Convert the usable area of classrooms planned with medium efficiency level of new construction to the gross building area given the following model factors: Net Assignable Square Feet: 10,000, Space Factor: 1.5, Building Efficiency Ratio: 67%