Page 19 - Mississippi 811 Magazine 2017 Issue 2

CONTINUED FROM pass 15 g

ONION x17 sl.oEINc AND EENCHING ,

Thi. procedure calls, iirst, tor clas.iiying the soil, then reterring to the charts 4.. .;, '

and illustrations in the OsHA standard to determine the correct angle ui the " ' A j
.loping or benching .1 '

From the OSHA standard _f , “

TypeSoi| Angle ofBarIk I ii 5-_
t—.» t, , ., g .
Stable Rock Vertical wall ~o ‘g, '
Type ASoi| 3/no 1 (H to V), or 53 degrees V "'3'
Type B Soil 1 to 1 (H to V), or 45 degrees
Type C Soil 1 ‘/2 to 1 (H to V), or 34 degrees __ ;_\_
. , , , .

ONION :2 7 TLMEER SHORINC. . _

Tlii. is a systern or wooden walers, cros. braces and uprights that .upport " ' "_ V‘ J ' a -

the walls of a trench or nxcilvatlnn. The OS!-LA standard .peciae. the " " , \.. .
.ize. of tlmbeza‘, ha.ed on the various type. of soil, the depth of the trench .

or excavation and the type of timber u.ed to bulld the structure (oak or

Douglas i’-tr) .

ONION #3 7ALuMINuIvI HYDRAULIC SHORINC , _ — ’ ‘
Hydraulic slioi-ing .y.tems have replaced a lot of timber .horing. Developed cw’ * V

in calitornia in the late 1950s, there are two main type. of hydraulic .horing . ‘ _
.ystems vertical .hore. and horizontal waler.. Both employ aluminum 7 Jfi 4‘

rails and hydraulic cylinder. that apply pre.sure to the wall. of a trench, . , W

creating an "ilrchlng effect” in the ad,acent .oil that prevents the wall. trorn ' t ,

collap.ing. e /

ONION x4 7 TRENCH SHIELDS

Trench shields are aluminum or .teel structures designed to protect worker.

by with.tanding the torees of a cavein Regardless of the rnatenal they are

made of, the principle. tor trench shields are the same.

ONION #5 7 SITE-SPECIFIC ENGINEERED SYSTENB

Orcmionally the chart‘ In the OSHA Standard for slaving and bend-insr 4 star Ni‘m‘7A oarsuv..r.- Wtstlllt‘ may to Mt‘ Dt‘»‘Nt)Itmt)ll to
or timber .hormg, as well rnanutactured .y.tems such as aluminum millet‘: tmv1<t‘r< HI r-air... .irv.».aair.. ctttmhtm;
hydraulic shoring or trench .hield., are not appropriate. There may he

lubsltz conditions or other tactors that prevent the use of all these .y.tems

In these .ituatioiis, a registered protes.ional engineer rnust design a system T S . _

.pecifically tor the ]nb. The engineer ha. to he regi.tered in the state where “ “‘“'“‘““"

the system will he used and will have to "stamp" the design There are By having a properly trained and authorized
addllional requirement. a. well, all of which are covered in the OSHA competent Eenon on.ite and following
standard the General I<equirernent. section or the

ts -
The properly trained and autlionzed Competent Person must in.pect rigorously and repeatedly in.pectmg every
excavation. daily tor excavation, you and your employees can

_ mdmim of Pwible m2_im; work satcly in trenches and excavations. .
- tailure of protective systems;

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- or other hazardous conditions. Erptipvicrit, LLC whit-h piondcs aalca, rcatal

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Inspection. rnu.t he conducted prior to the start of work and al.o as needed :3, [;‘:n"";'f,.?:
throughout each .hirt, atter rainstorm. and atter other potential hazard. W, W“, T',m),s,,,C,’y_,L,m U, w’,L,w_ ‘’ ‘
increa.ing events The Competent Person must also check adlacenl areas and ,,m,,__,,.,,U,,,,ds,,W' ,0,"

protective .y.terns (before and during use) and look always tor indications ‘ ' '

of po.siIole cave-ins and hazardous or potentially hazardou. conditions. 2013 MM WWW an , 1,