Page 20 - Damage Prevention Journal 2018 Issue 2
P. 20

commum mom PAGE 17


This procedure calls, iirst, iorclassitying the soil, then reterring to the charts  g 9. '

and illustrations in the OSHA standard to detei-inine the correct angle or the  W‘ '* g »
sloping or benching. , - ‘
From the osl-LA standard —: ' ‘ii

TypeS0i| Angle ofBarlk _ H V-‘:_
Stable Roek Vertical wall H J, 
2 — / " 
Type A Soil 3/4101 (H to V), or 53 degrees M 
Type B Soil 1 to 1 (H to V), or 45 degrees
TypeCSoi| 1‘/zto1 (H tov), or 34degrees :_ _; —;_\
. t _ r p A


This is a system or wooden walers, cross braces and uprights that support ’* 5 "— , .

the walls or a trench or excavation. The OSHA standard speciiies the sizes — — ' " 1 \.,, .

of timbers, based on the various types of soil, the depth ot the trench or ,

excavation and the type ot timber used to build the structure (oak or Douglas


Hydraulic shoring systems have replaced a lot or timber slioi-ing Developed a_, —'

in calitomia in the late 1950s, there are two main types of hydraulic shoring a  '

systems: vertical shores and horizontal walers. Both employ aluminum rails 2 _,§ V ‘

and hydraulic cylinders that apply pressure to the walls or a trench, creating , /"‘ ‘

an "arching ettect" in the adiacent soil that prevents the walls trom collapsing ‘ E , 7


Trench shields are aluminum or steel structures designed to protect workers

by withstanding the forces of a cavedn Regardless of the material they are

made or, the principles for trench shields are the same.


occasionally the charts in the osmt standard tor sloping and benching, or

timber shoring as well manutactured systems such as aluminum hydraulic 4 W H W 1, Wu 1' V W e m y M W M y W W W H
slioi-ing or trench shields, are not appropriate. There may be iohsite conditions V,y,,(j., gj,,;m ,,, ‘.,§,,,‘,,f,xfi,,f_,,f,o,, ‘.“,m,,,"§,,~. ‘ " ‘
or other tactors that prevent the use ot all these systems. in these siniations, a

registered protessional engineer must design a system speciiically tor the job.

The engineer has to be registered in the state where the system will be used .

and will have to "~'Ir1mp" the design There are additional requirements as To Summer-12:

well, all of which are covered in the osmt standard. Hy lmmg H Pmpmy mum and wflmnzzd
5.“, ,5 _ lnspm me Excavaiion competent Pnrwn onsite and following

the General Requirements section ot the
The properly trained and authorized competent Person must inspect OSHA smdmdy carefully dMif),,,g ‘hf
exravxmnna dmly for soil, then by ul|l|Zmg protective systems and
- indications of possible cave-ins; nsomusly and repeatedly Impeding Every
excavation, you and your employees can

' failure of pwmwe ~'y~'Ier-ls; work ~af2ly in trenches and excavations. Q
- hazardous atmospheres,

- or mher 1-azardou» cvndltinnm David Dow 15 Ct:-futmdcr uf Trctichsa/cty and
lnspections must be conducted prior to the start of \‘\’Ol'k and also as needed Swlgly ~ mun rm 7/ Undfrzmlmd Sflfvfy
throughout each shitt, atter rainstorms and atter other potential hazard. 5'I"'!""“’'’/ “C '”""" V“’”'”“5 “'5' ’""“'
increasing events. The Competent Person must also check adtacent areas and 9”“'1""'"”' "W" 5‘’'{‘‘9’ “"1 5“/W ”“"""X_’°
protective systems (before and during use) and look always tor indications of “’,“?’f""‘”"' ”“‘”"”"' """ “""fV ‘“”""”’”“
possible cave-ins and hazardous or potentially hazardous conditions V'5" ““"“’ T'““”5“/W-‘W ”’ “””’”-

is E Damage Frevemlun Juumal - em Issue 2

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