August 31, 2018 Design Management, Inc. Attn: Ms. Lila ...

August 31, 2018

Design Management, Inc. Attn: Ms. Lila Bellamente Re: Temporary Excavation / Shoring Recommendations Single Family Residence at 3841 Jason Street Denver, CO 80211

TRIAX Project No.: D18G119-TempShoring Ms. Bellamente:

Pursuant to your request, we are happy to present the following recommendations for the shoring of proposed temporary excavation at the above mentioned project site. It is our understanding that the proposed construction will be a new single family residence at the above mentioned project site.

We infer the following from the proposed excavation plan provided by the client.

• The maximum depth of excavation will be approximately 8 ft from the existing grade at the south side of the residence at the location of the proposed basement.

• The excavation will remain open for approximately three weeks and will be backfilled up on the completion of the construction of crawl space walls.

• The minimum distance from the top of excavation on all sides, to the property line is a minimum 5-ft.

• Where the foundation is designed as crawl space and the maximum depth of footings are 4-ft from existing grade, shoring piers may not be necessary. Where the total depth of excavation is less than 4-ft (based on 1H:1V), temporary excavation recommendations and benching requirements shall be followed.

The shoring pier design is based on our geotechnical investigation for the above mentioned project (Triax Project #D18G119, dated March 16, 2018).

The shoring piers should be installed a minimum of 5-ft beyond the excavation on

both sides, as indicated in the attached shoring plan. These piers must be installed a minimum of one week prior to the excavation of the site to allow concrete to partially cure. The supporting piers on the south side of the excavation shall be twelve inches in diameter and drilled twice the depth of the excavation plus one foot.

GEOTECHNICAL ENGINEERINGvQA/QC TESTING AND INSPECTIONSvENVIRONMENTAL SITE ANALYSES

As an example, a five feet excavation would require a minimum of seventeen (17) feet deep shoring piers, for a maximum excavation depth of 8-ft.

Pier spacing shall be a maximum of thirty six inches on center along the south

wall of the excavation abutting the neighboring property and to up to five feet beyond the excavation. Shoring piers may not be necessary where the foundation walls (of typical single family residences) are beyond 12-ft from the excavation and a minimum of 1.5H:1V temporary slopes can be safely constructed.

Based on our previous experience working at the vicinity of the project site and

available data from our boring logs, the subsurface soils can be classified as Type B per OSHA (1926 Subpart P App A). Soils classified as Type B could be excavated in a 1H:1V sloped configuration for a maximum depth of 20-ft. Benching of slope, if desired could be accomplished with a maximum of a 4-ft bench. To confirm our assumptions, We will require onsite inspection during the time of the excavation to observe the behavior of the soil and make adjustments to our recommendations if necessary. In such an event shoring piers or other structural shoring / bracing/ underpinning elements may be required to stabilize the excavation walls and affected structures.

Table 1 Shoring Piers (Excavation Depth = 8-ft Max)

Location Pier Diameter

(in.)

Pier Spacing

(in)

Embedment Depth (ft)

Total Length (ft) Reinforcing

South side of excavation

12 36 in. on center

Excav Depth +1 ft

(Excav. Depth *2 )+ 1-ft

3x #4 bars (Or)

4x#3 bars East and West

side of Excavation

Slope or Bench as desired at 1H:1V Max excavation depth = 4-ft at crawlspace locations (Excavation minimum of 5-ft from property line)

North side of excavation

Slope or Bench as desired at 1H:1V (except at basement location) Max excavation depth = 4-ft at crawlspace locations

(Excavation minimum of 5-ft from property line) The exposed face of the wall shall be protected from weather events such as rain

or snow. If significant sloughing of soils on other sides is observed, additional measures to stabilize the sloughing such as lagging or shotcrete might be required.

The piers shall be reinforced their entire length as outlined in table 1, placed in a

round configuration two inches from the sides of the piers. This design is approved for the soils found in the exploratory test holes at the

project site only and should not be used elsewhere. Should water be encountered during the drilling of these piers, casing and/or pumping may be required. Due to the types of soils encountered at the project site, casing of boreholes may be required. The drilled pier holes should be filled immediately after drilling so that loose soil or water does not infiltrate the holes and to avoid distortions of the holes. During the excavation process,

Not to Scale

Date:

Project No:

1173 S Madison Street

Shoring Piers (Actual Number of piers may vary based on field conditions)

BEDROOM 4

LIVING AREA

UP

CRAWL SPACE

GARAGE SLABABOVE

MECH./STORAGE

BATH. 4

1 1/4"=1'-0"BASEMENT LEVEL PLAN N

ORT

H

GF.1A B2 DC

1

4

3

5

6

2

5.1

E.1B1B FE

3040 CSM3040 CSM3040 CSM

A3.01

A3.01 2668

[email protected]"14T@11"

1

2 3

8

A3.12

A3.12

A3.11

A3.11

FURN. WHCRAWL SPACEACCESS

DROPPEDSOFFIT, RE:STRUCTURALDWGs

A4.13

EGRESS

CRAWL SPACE VENT, SEE VENT CALCS. SHT, A5.1

EGRESS EGRESS



1 1

1 1

1

1

PERIMETERDRAIN

1

1

1

1

26682668 2868

2468

12

14

9



CO

PYRI

GH

D18G119.TempShoring

8/31/18

Installed at 36 inches on center to the extent of foundation wall + 5-ft

Temporary Shoring3841 Jason StreetDenver CO

1 SHORING PLAN

NOT TO SCALE

Notes:1. Piers reinforced with 3x#4 or 4x#3 rebar placed in triangular configuration 2. Shoring pier concrete shall have average 28 day compressive strength f'c = 4000 psi and average 28 day compressive strength f'c = 4000 psi3. Piers shall be drilled in alternative sequence. A B A B A B A B A: Piers drilled first day, (concrete placed and allowed to cure minimum one day before piers designated B are drilled) B: Piers drilled second day4. Piers shall extend a minimum of 5-ft beyond excavation

1.5H:1V slope

Shoring Pier

S.1

1

Sheet S.0

S.1

2or4

Please note that thedrawing is not toscale. Number ofpiers shall beadjusted based onactual measurementson the field.

Ý

Not to Scale

Date:

Project No:

1173 S Madison Street

Shoring Piers (Actual Number of piers may vary based on field conditions)

D18G119.TempShoring

8/31/18

1 EXCAVATION CROSS SECTIONNOT TO SCALE

Bottom of Excavation

D =

9-ft

H=2

D+1

Max

imum

Dep

thof

Cut

= 9

-ft

3 SHORING PIER REINFORCING DETAILNOT TO SCALE

D =12 in.

Temporary Shoring3841 Jason StreetDenver CO

3 #4 Barsor 4x#3Bars

8-ft

2 Sloped Excavation (1.5V:1H)NOT TO SCALE

Sheet S.1

8-ft

1H1V

4 Benching DetailNOT TO SCALE

4-ft max

4-ft max

1H:1V

Top of Exc.

Bottom of Exc.

Letterfrom neighbourto be provided by architectinforming them about the excavation

vinodRavindran

Line

vinodRavindran

Line

"Design Management"ClientShoring Piers

"3841 Jason St."ProjName

Height of Cantilever, 9Hc "D18G119.Tempshoring"ProjNo

Surcharge Wt 200Ws

Concrete Strength 4000fc

Allowable Yield StrengthRein. Steel Yield Strength ksi60fy ksi60σall

Pier Diameter 12Dia

Pier Spacing 36S

9DfDepth of Foundation (ft)

Ground Water Level 35Hw

Stratum 1 Stratum 2

13s1 10S2

105γ1 108γ2

200c1 0c2

0.8c1c1corr 0.8c2c2corr

160c1corr 0c2corr

2c1corrqu1 2c2corrqu2

320qu1 0qu2

deg25φ1 deg32φ2

0.08π180φ1ACF

2ACF24EW

round , 112ACF

EWAPW

4APW

12S12Dia

ACFf 0.67f

4 Sep 2018 11:09:01 - shoring - 3346 Josephine.sm

1 / 4

sin φ11

sin φ11ka1t sin φ21

sin φ21ka2t

0.31ka2t0.41ka1t

0.33ka20.41ka1

sin φ11

sin φ11kp1temp

sin φ21sin φ21

kp2temp0.8kp1tempkp1temp 0.8kp2tempkp2temp

1.97kp1temp2.6kp2temp1.97kp1

2.4kp2Compute Pressures

Wska1p1 82p1

ka1c1corr2Hcγ1ka1p2 182.55p2

ka2c2corr2Distγ2round , 2ka2p3

ka2c2corr2γ2round , 2ka2p3part 35.64p3part

kp2c2corr2Distγ2round , 2kp2p4

γ2round , 2kp2p4part 259.2p4part

Compute Forces

DfHcp1F1 0F1

Hcp221F2

821.48F2

Distp2p1F3 p2p1F3part 264.55F3part

Distp321F4

p3part0.5F4Part 17.82F4Part

Distp421F5

p4part0.5F5Part 129.6F5Part

ΣM@0 = 0

F5Dist31F1Hc

21DistF2Hc

31DistF3Dist

21F4Dist

31M0


2 / 4

F5Part31F4Part3

1D3terms37.26D3terms

F3part21D2terms

132.28D2terms

F1F2D1terms 821.48D1terms

F1Hc21F2Hc

31D0Terms

3102.46D0Terms

D0TermsxD1terms2

xD2terms3

xD3termsf x

solve , x0f xres resDist7.6res

Approximate Result0M0

ft1resDist1.2DistDistFS

ft9DistFS Depth of Embedment

Find point of Zero ShearΣFh=0F1+F2+F3+F4-F5=0

F1F2xF3part2

xF5PartF4Partg x

solve , xg xres1

4.141.77

res1ft6yFMax

ft6yFMax Point of Zero Shear


3 / 4

Maximum moment occurs at point of zero shear

5y

D0TermsyD1terms2

yD2terms3

yD3termsMMax

ftkip10001MMaxMMax

ftkip5.22MMax Maximum Moment

Amount of Steel Needed

σall

MMaxSecMod

3in1.04SecMod

in1Diaσall0.81

3MMaxAs

2in0.32As

round , 0BarArea

AsNoOfBarsin

83BarDia 2

in0.11BarArea1. "#3"BarNo

3NoOfBars

Alternative

in21BarDia 2

in0.2BarArea2. "#4"BarNo

round , 0BarArea

AsNoOfBars

2NoOfBars

Use alternate minimum of 3 #4 bars or 4 #3 bars in a triangle configuration


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August 31, 2018 Design Management, Inc. Attn: Ms. Lila ...

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