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Simple Calculations

on

Vertical Loadingof the Indianola Dock

By: Lisa and Matt Fitch

For: Consideration by the

Commissioners of the Port of Indianola

11 August 2013

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Summary

Purpose Statement: Presentation provided to assist the Port Commissioners in risk

based assessment of vertical loads in support of re-opening thedock.

Bottom Line Up Front: Based on available facts and the load limit from CHE (45psf), the

area of dock should be able to vertically sustain up to 1,066adult males. Reasonable assessment of typical loading based onhistorical events would imply that this load should not be seenthis year.

Table of contents: The Math

Applied to the Indianola Dock

Points of Consideration

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The Math

Per the engineering report from CHE,

presented to the Port and the town, a

conservative allowable live load limit (LL) on

the dock is 45 pounds per square foot (psf).

If the LL is multiplied by an area in

consideration, the maximum loading

(MaxLoad) for that area can be calculated.

LL = 45psf (per CHE)

MaxLoad = Area x LL

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The Math (cont)

To identify the number of people associated with

a maximum allowable load, just divide by the

average weight of a person (AvgWeight).

Average weight of adults over the age of 20 years,

from the Center for Disease Control data, are: Male: 195.5 pounds (lbs)

Female: 166.2 lbs

# of people allowable =MaxLoad

AvgWeight

An AvgWeight of 200 lbs

can be used for

conservative calculations.

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The Math (cont)

Example of the math applied, assuming an

area 6 wide by 6 long:

Area = 6 x 6 = 36 square feet (sf)

MaxLoad = Area x Load Limit

= 36sf x 45psf (from CHE)

= 1,620 lbs

# of people allowable = MaxLoad / AvgWeight= 1,620 lbs / 200 lbs (from CDC)

= 8.1 adult men

Roughly 8 adult men could safely be in a 6x6 area

with these constraints. 5

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The Indianola Dock

(simplified) Dock Area Simplified:

700 long (rough, for calculations) walkway by 6 wide

539.5 sf end section

4,739.5 sf total area

Dock Loading (45 psf load limit from CHE):

Area x Load Limit / average weight = allowable number of people

4,739.5 sf x 45 psf / 200 lbs = 1,066 people

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6

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36sfeach

36sf x 45psf = 1,620 lbs

1,620 lbs / 200 lbs

8.1 adult men per 6 LF

539.5sf x 45psf = 24,277.5 lbs

24,277.5 lbs / 200 lbs

121 adult men

539.5 sf

31

20.5

15

14.5

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Points of Consideration

Based on available facts and the load limit from CHE(45psf), the total area of dock should be able to verticallysustain up to 1,066 adult males. Or, 8.1 adult men per 6linear feet of walkway and 121 adult men at the end of thedock.

Reasonable assessment of typical loading based onhistorical events would imply that this total load should notbe seen this year.

Authors opinion the dock could be opened right now,

with minimal risk to the public and to the Port, untilsummer 2014. If no mitigation efforts have beencompleted by that time, the dock could be closed for thehigher use period.

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