Seismic Evaluation Report - MAMS Gym.pdf

MT ANGEL MIDDLE SCHOOL GYMNASIUM

460 E Marquam St, Mt Angel, OR 97362

Mt Angel School District

Seismic Evaluation Report For:

Prepared By:

ZCS Engineering & Architecture

Matthew R. Smith, PE, SE, Principal

524 Main Street, Suite 2, Oregon City, OR 97045

T: 503.659.2205 | E: MattS@zcsea.com

Mt Angel School District February 2022

Mt Angel Middle School Seismic Evaluation Project No: P-2615-21

Project Summary Information

Building

Part

Building Part

Name

Included in Retrofit

Year

Built

Building

Type***

Nonstructural

Retrofits

Included in

Scope Y/N***

Previous Seismic

Retrofit Y/N***

(Year if Yes)

A Gymnasium and

Cafeteria

Y 1968 URM Y N

B Music Room Y 1996 W2 Y N

C Classrooms N 1968 Y (2014)

D Science Building N 1996

E Main Office N 1968 Y (2014)

F Classrooms N 1968

G Library N 1968

*** Entries required ONLY for building parts included in proposed seismic retrofit

Nonstructural deficiencies posing life safety risk MUST be included in the scope of work and budget.

Seismic fragility inputs for existing buildings with previous seismic retrofits MUST be adjusted to reflect previous seismic retrofit measures completed for a building part.

Total Retrofit Cost $2,494,755

Retrofit Square Feet 18,700

Retrofit Cost per

Square Foot

$ 133.41

Is the campus within a tsunami, FEMA flood zone, landslide/slope instability, liquefaction potential or other high hazard area? If so, provide documentation.

No, see geotechnical report.

Engineering Report Checklist

☒ Engineering Report Cover Page

☒ Project Summary Page Page 1

☒ Building Parts Identification Page 5

☒ Statement of the Performance Objective Page 7

Summary of Deficiencies

☒ Structural Seismic Deficiencies Page 11

☒ Nonstructural Seismic Deficiencies Page 12

Summary of Mitigation/Retrofit

☒ Structural Mitigation/Retrofit Page 11

☒ Nonstructural Mitigation/Retrofit Page 12

Summary Construction Cost Estimate

☒ Direct Cost Page 15

☒ Indirect Soft Cost Page 15

☒ Certification Statement by Engineer Page 16

ASCE 41-17 Tier 1 Checklist

☒ Basic Configuration Checklist Appendix B

☒ Building System Structural Checklist Appendix B

☒ Nonstructural Checklist Appendix B

☒ Retrofit Drawings & Sketches Appendix C

☒ DOGAMI or Geotechnical Report Appendix D

☒ Itemized Construction Cost Estimate Appendix E

☒ Rapid Visual Screening Appendix F

1.0 Project Introduction

Mt Angel School District is located in Mt Angel, Oregon in Marion County. The District operates a number of schools located within the community including the property of interest, Mt Angel Middle

School. The District has retained ZCS Engineering and Architecture (ZCS) to perform a seismic evaluation of Mt Angel Middle School that provides the District with an objective, comprehensive analysis of the condition of the building’s seismic resisting systems. The purpose of the evaluation is to determine the seismic lateral resisting system deficiencies when compared to buildings designed using modern building codes. This evaluation was performed in accordance with the American Society of Civil Engineers

“Seismic Rehabilitation of Existing Buildings ASCE/SEI 41-17”.

SEISMIC EVALUATION SNAPSHOT

Street Address 460 E Marquam St, Mt Angel, OR 97362

Evaluation Standard ASCE 41-17 (Tier 1 Analysis)

Target Building Performance Level Immediate Occupancy – BSE-1E; Life Safety – BSE-2E

Target Non-Structural Performance Level Position Retention – BSE-1E; Hazards Reduced – BSE-2E

ASCE 41 Building Type URM, W2

Site Soil Classification D

Seismic Zone Hazard Level High

Cost Estimate $2,494,755

2.0 Building Description

The structures reviewed in our analysis include the original gymnasium and cafeteria building, which was constructed in 1967 with a footprint of approx. 17,100 sqft. The building includes gym, locker rooms, cafeteria, and other utility rooms. The building is a single-story building, with mostly under-reinforced masonry walls and a wood roof system. Gym roof consists of glue-lam arches, wood joists and sheathing.

The foundations are concrete stem walls and footings, and the floor is concrete slab on grade.

In 1996 a 1,600 sqft music room building addition was constructed. This building is a single-story building with wood framed walls and roof system, and an under-reinforced masonry partition wall. The foundations are concrete stem walls and footings, and the floor is concrete slab on grade.

Photographs of the building parts included in this report are located in Appendix A.

Construction Year: 1968

Building Name: Gymnasium and

Cafeteria

Construction Type: URM

In Scope?: Yes

Construction Year: 1996

Building Name: Music Room

Construction Type: W2

In Scope?: Yes

Construction Year: 1968

Building Name: Classrooms

Construction Type: W2

In Scope?: No

Construction Year: 1996

Building Name: Classrooms

Construction Type: W2

In Scope?: No

Building Name: Main Office

Building Name: Classrooms

Building Name: Library

Figure 1

Mt Angel Middle School Key Plan

A

B

C

D

E

F

G

3.0 Definition of Building Types

After reviewing the facility and the existing drawings we have determined the lateral systems are defined as URM and W2. Per ASCE 41-17 the subject structure’s lateral system is defined as:

Unreinforced Masonry Bearing Walls URM – This building was initially reviewed as an RM1 construction type due to the presence of some reinforcing present in the wall construction. Through the RM1 Tier 1 evaluation it was determined that the walls are under-reinforced. Accordingly, this building is classified as a URM. These buildings have a perimeter bearing walls that consist of unreinforced clay brick, stone, or concrete masonry. Interior bearing walls, where present, also consist of unreinforced clay brick, stone, or concrete masonry. In older construction, floor and roof framing consists of straight or diagonal lumber sheathing supported by wood joists, which, in turn, are supported on posts and timbers. In more recent construction, floors consist of structural panel or plywood sheathing rather than lumber sheathing. The diaphragms are flexible relative to the walls. Where they exist, ties between the walls and the diaphragms consist of anchors or bent steel plates embedded in the mortar joints and attached to framing. The foundation system may consist of a variety of elements.

Wood Frames, Commercial and Industrial W2 – These buildings are commercial or industrial buildings with a floor area of 5,000 ft2 or more. There are few, if any, interior walls. The floor and roof framing consists of wood or steel trusses, glulam or steel beams, and wood posts or steel columns. The foundation system may consist of a variety of elements. Seismic forces are resisted by wood diaphragms and exterior stud walls sheathed with plywood, oriented strand board, stucco, plaster, or straight or diagonal wood sheathing, or they may be braced with rod bracing. Wall openings for storefronts and garages, where present, are framed by a post-and-beam framing.

4.0 Seismic Evaluation Methodology

The subject structure was evaluated using information gathered from site observations, available historic construction documents, and interviews with District staff. This information was then utilized to perform a structural evaluation as outlined in the American Society of Civil Engineer’s “Seismic Evaluation and

Retrofit of Existing Buildings – ASCE 41-17” (ASCE 41-17). ASCE 41-17 is referenced as the standard for seismic evaluations of existing buildings by the International Existing Building Code (IEBC) which is referenced by the Oregon Structural Specialty Code (OSSC). Further, ASCE 41-17 is the evaluation tool required by the Seismic Rehabilitation Grant Program for grant applications.

ASCE 41-17 provides several levels of evaluation (Tiers 1-3) depending on the level of evaluation and/or retrofit being performed. The Tier 1 evaluation is a quick checklist selected based on the type of construction and the performance objective of the building and is the baseline tool for preliminary seismic evaluations. In the case of this evaluation, a Tier 1 was performed to identify the likely structural deficiencies requiring retrofit to meet the performance objective stated below.

The OSSC classifies buildings into risk categories based on the type of building and occupancy type. The building’s risk category informs the required performance objective post retrofit. Risk categories I and II cover low risk structures. Risk category III includes school buildings that are not required to be used as emergency shelters and are relatively low occupancy. Risk category IV includes emergency service buildings and school buildings that are required to be designed as emergency shelters (high occupancy spaces). Figure 2, below, identifies the performance objective for each risk category.

The primary objective of the adjusting performance objectives relative to risk category is to ensure that the subject building is capable of performing in the necessary manner following a seismic event. In the case of a risk category III building, the intention is to ensure that the building is adequately stable following an earthquake to provide egress for occupants out of the building. Prior to reoccupation, the building would need evaluated and significant structural damage preventing reoccupation may be present. For risk category IV structures, the intent is that the building can be inspected then immediately reoccupied following a seismic event to function in its intended role as an emergency service building or as a high occupancy space capable of acting as an emergency structure.

In accordance with the table below, these sections A and B of this school are categorized as a risk category IV structures and were evaluated to meet the Life Safety structural performance and Hazards

Reduced nonstructural performance level for BSE-2E loading and the Immediate Occupancy structural performance and Position Retention nonstructural performance level for BSE-1E loading.

Figure 2

Building Performance Objectives

Source: Table 2-2, ASCE 41-17: American Society of Civil Engineers – Seismic Evaluation and Retrofit of Existing Buildings

5.0 Seismicity

Seismic design is based on site specific parameters that relate to the location of the building relative to faults and the soil that supports the building. The United States Geologic Survey has developed seismic design data that is utilized to perform the calculations specified in ASCE 41-17. The table below summarizes the factors appropriate for computing the seismic lateral loads for the design earthquake specified in ASCE 41-17.

SITE SPECIFIC SEISMICITY

Soil Density Stiff soil

ASCE 7-16 Soil Classification D

BSE-1E:

Sxs 0.321

Sx1 0.182

BSE-2E:

Sxs 0.758

Sx1 0.552

Soil Condition Amplification Factors (FV, FA) Fv = 1.6 - Fa = 2.4

ASCE 41 Site Seismicity High

Source: SEAOC and OSHPD Seismic Design Maps, https://seismicmaps.org/

6.0 Site Specific Hazards

Site specific hazards were assessed as part of our engineering evaluation. The hazards evaluated in our analysis included liquefaction, slope failure, surface fault rupture, and tsunami potential. These potential hazards were evaluated using ASCE 41-17 guidelines, as well as information provided by the online

Oregon HazVu: Statewide Geohazards Viewer, maintained by the Department of Geology and Mineral

Industries (DOGAMI). Tsunami risk was evaluated using the ASCE Tsunami Hazard Tool. Results from the

HazVu analysis are included in Appendix D along with a geotechnical report. Unless noted below, the hazards listed above are not present at the site.

Liquefaction

This project is located within a liquefaction hazard area as identified by the DOGAMI Oregon HazVu. To ensure that an acceptable level of due diligence was performed during the application phase of the project a geotechnical engineer was hired to perform a review of the hazard and make recommendations based on available information with respect to the severity. Per the geotechnical report, attached in Appendix D, liquefaction is considered a low risk for the site and no mitigation is required.

7.0 Deficiencies and Repairs

The table below summarizes both the structural and nonstructural deficiencies noted in the Tier 1 evaluation and states both the proposed retrofit methodology and the plan key note that corresponds to the scope items in the preliminary plans and the cost estimate. See Appendix B for complete Tier 1 check sheets. Drawings illustrating the proposed retrofit measures are attached in Appendix C.

Tier 1

Deficiency

Description

Deficiency Statement Repair Statement

Plan

Key

Note

LOAD PATH The structure does not contain a complete, well-defined load path, including structural elements and connections, that serves to transfer the inertial forces associated with the mass of all elements of the building to the foundation.

Provide a complete, well-defined load path by installing new elements and connections as needed to transfer inertial forces from all elements of the building to the foundation.

S1

REDUNDANCY The number of lines of shear walls in each principal direction is less than 2.

Install new shear walls to ensure a minimum of 2 shear lines in each principal direction.

S2

WALL

ANCHORAGE

Exterior concrete or masonry walls that are dependent on the diaphragm for lateral support are not anchored for out-of-plane forces at each diaphragm level with steel anchors, reinforcing dowels, or straps that are developed into the diaphragm. Connections do not have strength to resist the connection force calculated in the Quick Check procedure of Section 4.4.3.7.

Install new out-of-plane anchorage.

S3

WOOD LEDGERS The connection between the wall panels and the diaphragm induces cross-grain bending or tension in the wood ledgers.

Install new out-of-plane anchorage.

S4

TRANSFER TO

SHEAR WALLS

Diaphragms are not connected for transfer of seismic forces to the shear walls, or the connections are not able to develop the shear strength of the walls or diaphragms.

Install new hardware for transfer of seismic forces from diaphragm to shear walls.

S5

PROPORTIONS The height-to-thickness ratio of the shear walls at each story is greater than the following:

Top story of multi-story building 9

First story of multi-story building 15

All other conditions 13

Install new steel strongback columns to resist out-of-plane forces or strengthen existing wall elements using fiber-reinforced polymer (FRP) or brace URM walls with new wood shear walls.

S6

PLAN

IRREGULARITIES

There is not tensile capacity to develop the strength of the diaphragm at reentrant corners or other locations of plan irregularities.

Provide new drag elements. S7

CROSS TIES There are not continuous cross ties between diaphragm chords.

Provide new continuous cross ties between diaphragm chords.

S8

DIAGONALLY

SHEATHED AND

UNBLOCKED

DIAPHRAGMS

Not all diagonally sheathed or unblocked wood structural panel diaphragms have horizontal spans less than 30 ft and aspect ratios less than or equal to 3-to-1.

Install new blocked plywood diaphragm.

S9

EMERGENCY

POWER

Equipment used to power or control

Life Safety systems is not anchored or braced.

Anchor and brace equipment used to power or control Life

Safety system.

N1

UNREINFORCED

MASONRY

Unreinforced masonry or hollow-clay tile partitions are not braced at a spacing of at most 10 ft in Low or

Moderate Seismicity, or at most 6 ft in

High Seismicity.

Brace under-reinforced masonry partitions.

N2

PENDANT

SUPPORTS

Light fixtures on pendant supports are not attached at a spacing equal to or less than 6 ft. Unbraced suspended fixtures are not free to allow a 360-degree range of motion at an angle not less than 45 degrees from horizontal without contacting adjacent components. Alternatively, if rigidly supported and/or braced, they are not free to move with the structure to which they are attached without damaging adjoining components. The connection to the structure is not capable of accommodating the movement without failure.

Provide independent support for light fixtures.

N3

LENS COVERS Lens covers on light fixtures are not attached with safety devices.

Install safety devices for light fixture lens covers.

N4

OVERHEAD

GLAZING

Glazing panes of any size in curtain walls and individual interior or exterior panes more than 16ft.2 in area are not laminated annealed or laminated heat-strengthened glass or are not detailed to remain in the frame when cracked.

Remove glazing and replace with new safety glass windows system or infill walls segments.

N5

TIES Masonry veneer is not connected to the backup with corrosion-resistant ties.

There is not a minimum of one tie for every 2-2/3 ft.2, or the ties have spacing greater than the following: for Life

Safety in Low or Moderate Seismicity, 36 in.; for

Life Safety in High Seismicity and for

Position Retention in any seismicity, 24 in.

Secure existing masonry veneer with new stitch ties or remove and replace with new tied masonry veneer or other cladding system.

N6

WEAKENED

PLANES

Masonry veneer is not anchored to the backup adjacent to weakened planes, such as at the locations of flashing.

Remove existing masonry veneer and replace with new tied masonry veneer or other cladding system.

N7

CANOPIES Canopies at building exits are not anchored to the structure at a spacing no greater than the following: for Life

Safety in Low or Moderate Seismicity, 10 ft; for Life Safety in High Seismicity and for Position Retention in any seismicity, 6 ft.

Seismically anchor existing canopies to the structure.

N8

FALL-PRONE

CONTENTS

Equipment, stored items, or other contents weighing more than 20lb whose center of mass is more than 4 ft above the adjacent floor level are not braced or otherwise restrained.

Brace equipment to structure. N9

FALL-PRONE

EQUIPMENT

Equipment weighing more than 20 lb whose center of mass is more than 4 ft above the adjacent floor level, and which is not in-line equipment, is not braced.

Brace and anchor equipment weighing more than 20 lb, whose center of mass is more than 4 ft above the adjacent floor level.

N10

IN-LINE

EQUIPMENT

Equipment installed in line with a duct or piping system, with an operating weight more than 75 lb, is not supported or laterally braced independent of the duct or piping system.

Independently support and laterally brace equipment with an operating weight more than 75 lb installed in line with a duct or piping system.

N11

SUSPENDED

EQUIPMENT

Equipment suspended without lateral bracing is not free to swing from or move with the structure from which it is suspended without damaging itself or adjoining components.

Remove suspended equipment or ensure that equipment is free to swing from structure without damaging itself or adjoining components.

N12

VIBRATION

ISOLATORS

Equipment mounted on vibration isolators is not equipped with horizontal restraints or snubbers and with vertical restraints to resist overturning.

Install horizontal restraints or snubbers and vertical restraints to resist overturning for equipment mounted on vibration isolators.

N13

HEAVY

EQUIPMENT

Floor-supported or platform-supported equipment weighing more than 400lb is not anchored to the structure.

Anchor floor-supported or platform-supported equipment weighing more than 400lb to the structure.

N14

ELECTRICAL

EQUIPMENT

Electrical equipment is not laterally braced to the structure.

Laterally brace electrical equipment to the structure.

N15

CONDUIT

COUPLINGS

Conduit greater than 2.5 in. trade size that is attached to panels, cabinets, or other equipment and is subject to relative seismic displacement does not have flexible couplings or connections.

Install flexible couplings or connections for conduit greater than 2.5 in. trade size that is attached to panels, cabinets, or other equipment and is subject to relative seismic displacement.

N16

FLEXIBLE

COUPLINGS

Fluid and gas piping does not have flexible couplings.

Install flexible couplings for fluid and gas piping.

N17

FLUID AND GAS

PIPING

Fluid and gas piping is not anchored or braced to the structure to limit spills or leaks.

Anchor and brace fluid and gas piping to the structure.

N18

C-CLAMPS One-sided C-clamps that support piping larger than 2.5 in. in diameter are not restrained.

Install restraints for one-sided

C-clamps that support piping larger than 2.5 in. in diameter.

N19

DUCT BRACING Rectangular ductwork larger than 6 ft2 in cross-sectional area and round ducts larger than 28 in. in diameter are not braced. The maximum spacing of transverse bracing exceeds 30 ft. The maximum spacing of longitudinal bracing exceeds 60 ft.

Install bracing for all rectangular ductwork larger than 6 ft2 in cross-sectional area and round ducts larger than 28 in. in diameter.

N20

In addition to the structural and nonstructural deficiencies noted above, the gravity load resisting system was reviewed to identify obvious insufficient gravity components. Insufficient gravity elements can cause failure during seismic events. These gravity deficiencies are based on visual observations of the existing structural elements. No formal structural analysis was performed during this evaluation of the gravity resisting element.

Existing glue laminated beams built prior to 1970 were under designed based on inadequate material stress information available at the time. This results in beams that cannot be relied upon to support code prescribed gravity loading. The beams will be retrofit and strengthened to support code required gravity loading. This is deficiency/repair/plan note S10.

Based upon ZCS’s previous experience and discussions with site personnel the building contains hazardous materials. These materials will need to be dealt with on a case-by-case basis as they are encountered during the project.

8.0 Preliminary Construction Cost Estimate

The attached engineer’s opinion of probable cost has been developed by ZCS. ZCS has a successful record of completing seismic rehabilitation projects within the State of Oregon. The prices provided in the attached cost estimate have been developed using the extensive list of past projects as a baseline for this project. These prices are based on Oregon BOLI wage rates. The cost estimate is broken down into multiple line items associated with each major task (general conditions, foundation, structural steel, MEP, etc) associated with the rehabilitation. Additional line items are included for design associated permit costs, and owner construction management. A complete breakdown of the cost estimate can be found in Appendix E.

DIRECT COST

Construction $ 1,850,200

Engineering $ 290,700

Construction Management $ 61,200

Relocation $ 26,600

Construction Contingency $ 266,055

TOTALS AND SUMMARY

Total Cost Estimate $ 2,494,755

Match Funds $ 0

Total Amount Requested from SRGP $ 2,494,755

Total Area 18,700

Cost/Square Foot $ 133.41

9.0 Conclusion and Certification Statement

The findings described in this report have been limited to the lateral force-resisting structural system and general assessment of the gravity force-resisting elements. Based on our visual observations, we find the structure to be in relatively good condition and generally safe for occupancy. No significant damage to the existing structural system was discovered.

Given the current condition of the structure, the current code section on existing buildings does not mandate that upgrades are required unless the building is scheduled for repairs, alterations, additions, or change in occupancy. To clarify, upgrades outlined in this report are strictly at the discretion of the

District.

Please contact our office if you would like to discuss our findings. Please review the attached schematic drawings that can be used to refine a scope and budget.

Certification Statement

ZCS Engineering & Architecture’s professional staff has reviewed the subject building and the deficiencies noted in the Tier 1 evaluation, developed seismic retrofit solutions to rectify the deficiencies, and developed the engineering cost estimate. The project cost estimate was developed by

ZCS based on unit costs from our extensive list of past seismic retrofit projects as a baseline. We certify to the best of our knowledge, based on known and readily identifiable existing conditions, that all the seismic deficiencies present in the building are included in the retrofit scope of work and that all the retrofit’s scope of work elements are included in the cost estimate.

Matthew R. Smith, PE, SE

Appendix A:

Figures

Figure 1: Gymnasium South Elevation

Figure 2: Gymnasium East Elevation

Figure 3: Music Room North Elevation

Figure 4: Cafeteria Interior

Figure 5: Cafeteria Interior

Figure 6: Gymnasium Interior

Appendix B:

Tier 1 Check Sheets

Appendix C:

Preliminary Seismic Retrofit

Drawings

G0.0

COVER SHEET

SYMBOLS

A0.0

A0.0 ab c d

DOOR NUMBER

FINISH TYPE

WALL TYPE TAG

CEILING TYPE

CEILING HEIGHT,

A.F.F.

DATUM OR REFERENCE POINT

DRAWING REFERENCE

SHEET REFERENCE

INTERIOR ELEVATION

REFERENCE

DRAWING REFERENCE

SHEET REFERENCE

INTERIOR ELEVATION

BUILDING & WALL SECTION

DRAWING REFERENCE

SHEET REFERENCE

ELEVATION

DRAWING REFERENCE

SHEET REFERENCE

ENLARGED PLAN

DETAIL REFERENCE

ALIGN

CONTINUATION

CLOUDED AREA INDICATING

CURRENT REVISION

"DELTA" WITH CURRENT

REVISION NUMBER

PREVIOUS REVISION

(NOT ATTACHED TO

CURRENT CLOUD)

WINDOW/GLAZING TAG

CL CENTERLINE

MATCHLINE

A0.0

A0.0

X

XX

KEYNOTE

DRAWING REFERENCE

SHEET REFERENCE

ACT1

8'-0"

X

XXX

ROOM

NAME

00SF

ROOM NAME

ROOM NUMBER

ROOM AREA

SX.X

ABBREVIATIONS

(E) EXISTING

(N) NEW

(R) REMOVE

A.C. ASPHALT CONCRETE

A.C.B. ACOUSTICAL BOARD

A.C.P. ACOUSTICAL PANEL

A.C.T. ACOUSTICAL CEILING TILE

A.D. AREA DRAIN

ADJ. ADJUSTABLE

A.F. ACCESS FLOORING

AGGR. AGGREGATE

A..F. ABOVE FINISHED FLOOR

BD. BOARD

BITUM. BITUMINOUS

BKP. BACKING PLATE

BM. BEAM

BOT./B.O. BOTTOM/BOTTOM OF

C.B. CATCH BASIN

CEM. CEMENT

CER. CERAMIC

C.G. CORNER GUARD

C.I. CAST IRON

C.J CONTROL JOINT

CLG. CEILING

CLKG. CAULKING

CLO. CLOSET

CLR. CLEAR

CMU CONCRETE MASONRY UNIT

C.O. CASED OPENING

CONN CONNECTION

CORR. CORRIDOR

CPT. CARPET

CTSK. COUNTERSUNK

C.T. CERAMIC TILE

CTR. CENTER

D.F. DRINKING FOUNTAIN

DET. DETAIL

DISP. DISPENSER

DR. DOOR

DWR. DRAWER

D.S. DOWNSPOUT

D.S.A. DRY STANDPIPE

E.J. EXPANSION JOINT

EL. ELEVATION

EXPO. EXPOSED

EXP. EXPANSION

F.A. FIRE ALARM

FB. FLAT BAR

F.D. FLOOR DRAIN

FDN. FOUNDATION

FE FIRE EXTINGUISHER

F.A. FLAT HEAD

F.O.C FACE OF CONCRETE

F.O.F FACE OF FINISH

F.O.S. FACE OF STUDS

F.S. FULL SIZE

FTG. FOOTING

FUT. FUTURE

G.A. GAUGE

G.L. GRID LINE

GLB. GLULAM BEAM

G.B. GRAB BAR

GND. GROUND

GYP. GYPSUM

G.W.B. GYPSUM WALL BOARD

H.B. HOSE BIBB

H.C. HOLLOW CORE

H.M. HOLLOW METAL

J.B. JUNCTION BOX

J.O.H. JAMB OPENING HEIGHT

J.O.W. JAMB WIDTH

JT. JOINT

LAM. LAMINATE

L.P. LOW POINT

M.C. MEDICINE CABINET

M.D.F. MEDIUM DENSITY

FIBERBOARD

M.D.O. MEDIUM DENSITY OVERLAY

MEMB. MEMBRANE

MH. MANHOLE

MIR. MIRROR

M.O. MASONRY OPENING

M.P. MIDPOINT

M.S. MACHINE SCREW

MTD. MOUNTED

MUL. MULLION

NOM. NOMINAL

N.T.S. NOT TO SCALE

OBS. OBSCURE

O.C. ON CENTER

O.C.D. OVERHEAD COILING DOOR

O.C.G OVERHEAD COILING GRILLE

O.D. OUTSIDE DIAMETER

O.F.C.I. OWNER FURNISHED

CONTRACTOR INSTALLED

O.F.D. OVERFLOW DRAIN

O.F.O.I. OWNER FURNISHED OWNER

INSTALLED

OH. OPPOSITE HAND

PL. PLATE

P.LAM. PLASTIC LAMINATE

PLAS. PLASTER

P.C.P. PORTLAND CEMENT

PLASTER

PR. PAIR

PTN. PARTITION

R.C.P. REFLECTED CEILING PLAN

R.D. ROOF DRAIN

RL. RELOCATE

R.O. ROUGH OPENING

RWD. REDWOOD

R.W.L. RAIN WALL LEADER

REV. REVERSED

S.C. SOLID CORE

S.C.D. SEE CIVIL DRAWINGS

SHR. SHOWER

S.J. SCORE JOINT

S.L.D. SEE LANDSCAPING

DRAWINGS

S.M. SHEET METAL

S.M.D SEE MECHANICAL

DRAWINGS

S.O.G. SLAB ON GRADE

S.S.D. SEE STRUCTURAL

DRAWINGS

S.S. STAINLESS STEEL

STR. STRUCTURAL

S.T.S. SELF TAPPING SCREW

SUSP. SUSPENDED

TRD. TREAD

T.B. TOWEL BAR

T.C. TOP OF CURB

T&G. TONGUE AND GROOVE

THK. THICK

T.P. TOP OF PAVEMENT

T.W. TOP OF WALL

V.I.F. VERIFY IN FIELD

V.T.R. VENT THROUGH ROOF

W.C. WATER CLOSET

W.O. WINDOW OPENING

ABBREVIATIONS

PROJECT NO:

DRAWN:

CHECKED:

DATE:

O N

E

IN

C H

E Q

U

AL

S

FU

LL

S

C

AL

E

MOUNT ANGEL SCHOOL

DISTRICT 91

730 E. MARQUAM ST.

MOUNT ANGEL, OR 97362

MOUNT ANGEL

MIDDLE SCHOOL

GYM SEISMIC

RETROFIT

524 Main Street, Suite 2, Oregon City, Oregon 97045 | 503-659-2205

PR

EL

IM

IN

AR

Y

D

ES

IG

N

FEB. 2022

MRS

MEG

P-2615-21

REVISION ID: DATE:

-P

RELIM

IN

ARY-

NOT FOR C

ONSTRUCTIO

N

G0.0 COVER SHEET

A1.1 BUILDING KEY PLAN

S1.1 REPAIR KEY NOTES

S2.1 AREA A & B ROOF FRAMING PLAN

VICINITY MAP

GYMNASIUM SOUTH ELEVATION:SHEET INDEX GYMNASIUM EAST ELEVATION:

MUSIC ROOM NORTH ELEVATION: CAFETERIA INTERIOR:

CAFETERIA INTERIOR: GYMNASIUM INTERIOR:

MOUNT ANGEL MIDDLE SCHOOL GYM SEISMIC RETROFIT

PRELIMINARY DESIGN

MOUNT ANGEL SCHOOL DISTRICT 91

460 E MARQUAM ST.

MOUNT ANGEL, OR 97362

PROJECT

LOCATION

AutoCAD SHX Text

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OREGON

TRUE/PROJECT

NORTH

*SITE PLAN NOT

TO SCALE

AREA A:

GYMNASIUM AND

CAFETERIA

±17,100 S.F.

IMMEDIATE OCCUPANCY

URM

AREA B:

MUSIC ROOM

±1,600 S.F.

IMMEDIATE OCCUPANCY

W2

AREA D:

SCIENCE BUILDING

±3,800 S.F.

NOT IN SCOPE

W2

AREA C:

CLASSROOMS

±3,000 S.F.

NOT IN SCOPE

W2

AREA E:

MAIN OFFICE

±4,300 S.F.

NOT IN SCOPE

W2AREA F:

CLASSROOMS

±9,500 S.F.

NOT IN SCOPE

W2

AREA G:

LIBRARY

±4,500 S.F.

NOT IN SCOPE

W2

A1.1

BUILDING

KEY PLAN

PROJECT NO:

DRAWN:

CHECKED:

DATE:

O N

E

IN

C H

E Q

U

AL

S

FU

LL

S

C

AL

E

MOUNT ANGEL SCHOOL

DISTRICT 91

730 E. MARQUAM ST.

MOUNT ANGEL, OR 97362

MOUNT ANGEL

MIDDLE SCHOOL

GYM SEISMIC

RETROFIT

524 Main Street, Suite 2, Oregon City, Oregon 97045 | 503-659-2205

PR

EL

IM

IN

AR

Y

D

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IG

N

FEB. 2022

MRS

MEG

P-2615-21

REVISION ID: DATE:

-P

RELIM

IN

ARY-

NOT FOR C

ONSTRUCTIO

N

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STRUCTURAL REPAIRS:

S1. PROVIDE A COMPLETE, WELL-DEFINED LOAD

PATH BY INSTALLING NEW ELEMENTS AND

CONNECTIONS AS NEEDED TO TRANSFER

INERTIAL FORCES FROM ALL ELEMENTS OF THE

BUILDING TO THE FOUNDATION.

S2. INSTALL NEW SHEAR WALL.

S3. INSTALL NEW OUT-OF-PLANE ANCHORAGE.

S4. INSTALL NEW OUT-OF-PLANE ANCHORAGE.

S5. INSTALL NEW HARDWARE FOR TRANSFER OF

SEISMIC FORCES FROM DIAPHRAGM TO SHEAR

WALLS.

S6A. INSTALL NEW STEEL STRONGBACK COLUMNS

TO RESIST OUT-OF-PLANE FORCES.

S6B. STRENGTHEN EXISTING WALL ELEMENTS USING

FIBER-REINFORCED POLYMER (FRP).

S6C. BRACE URM WALLS WITH NEW WOOD SHEAR

WALLS.

S7. PROVIDE NEW DRAG ELEMENTS.

S8. PROVIDE NEW CONTINUOUS CROSS TIES

BETWEEN DIAPHRAGM CHORDS.

S9. INSTALL NEW BLOCKED PLYWOOD DIAPHRAGM.

S10. EXISTING GLULAM ARCHES TO BE RETROFITTED.

NON-STRUCTURAL REPAIRS:

N1. ANCHOR AND BRACE EQUIPMENT USED

TO POWER OR CONTROL LIFE SAFETY

SYSTEM.

N2. BRACE UNDER-REINFORCED PARTITIONS.

N3. PROVIDE INDEPENDENT SUPPORT FOR

LIGHT FIXTURES.

N4. INSTALL SAFETY DEVICES FOR LIGHT

FIXTURE LENS COVERS.

N5. REMOVE GLAZING AND REPLACE WITH

NEW SAFETY GLASS WINDOWS SYSTEM

OR INFILL WALLS SEGMENTS.

N6. SECURE EXISTING MASONRY VENEER

WITH NEW STITCH TIES OR REMOVE AND

REPLACE WITH NEW TIED MASONRY

VENEER OR OTHER CLADDING SYSTEM.

N7. REMOVE EXISTING MASONRY VENEER

AND REPLACE WITH NEW TIED MASONRY

VENEER OR OTHER CLADDING SYSTEM.

N8. SEISMICALLY ANCHOR EXISTING

CANOPIES TO THE STRUCTURE.

N9. BRACE EQUIPMENT TO STRUCTURE.

N10. BRACE AND ANCHOR EQUIPMENT

WEIGHING MORE THAN 20 LB, WHOSE

CENTER OF MASS IS MORE THAN 4 FT

ABOVE THE ADJACENT flOOR LEVEL.

N11. INDEPENDENTLY SUPPORT AND

LATERALLY BRACE EQUIPMENT WITH AN

OPERATING WEIGHT MORE THAN 75 LB

INSTALLED IN LINE WITH A DUCT OR

PIPING SYSTEM.

N12. REMOVE SUSPENDED EQUIPMENT OR

ENSURE THAT EQUIPMENT IS FREE TO

SWING FROM STRUCTURE WITHOUT

DAMAGING ITSELF OR ADJOINING

COMPONENTS.

N13. INSTALL HORIZONTAL RESTRAINTS OR

SNUBBERS AND VERTICAL RESTRAINTS

TO RESIST OVERTURNING FOR

EQUIPMENT MOUNTED ON VIBRATION

ISOLATORS.

N14. ANCHOR FLOOR-SUPPORTED OR

PLATFORM-SUPPORTED EQUIPMENT

WEIGHING MORE THAN 400LB TO THE

STRUCTURE.

N15. LATERALLY BRACE ELECTRICAL

EQUIPMENT TO THE STRUCTURE.

N16. INSTALL flEXIBLE COUPLINGS OR

CONNECTIONS FOR CONDUIT GREATER

THAN 2.5 IN. TRADE SIZE THAT IS

ATTACHED TO PANELS, CABINETS, OR

OTHER EQUIPMENT AND IS SUBJECT TO

RELATIVE SEISMIC DISPLACEMENT.

N17. INSTALL flEXIBLE COUPLINGS FOR FLUID

AND GAS PIPING.

N18. ANCHOR AND BRACE FLUID AND GAS

PIPING TO THE STRUCTURE.

N19. INSTALL RESTRAINTS FOR ONE-SIDED

C-CLAMPS THAT SUPPORT PIPING

LARGER THAN 2.5 IN. IN DIAMETER.

N20. INSTALL BRACING FOR ALL

RECTANGULAR DUCTWORK LARGER

THAN 6 FT2 IN CROSS-SECTIONAL AREA

AND ROUND DUCTS LARGER THAN 28 IN.

IN DIAMETER.

S1.1

REPAIR KEY

NOTES

PROJECT NO:

DRAWN:

CHECKED:

DATE:

O N

E

IN

C H

E Q

U

AL

S

FU

LL

S

C

AL

E

MOUNT ANGEL SCHOOL

DISTRICT 91

730 E. MARQUAM ST.

MOUNT ANGEL, OR 97362

MOUNT ANGEL

MIDDLE SCHOOL

GYM SEISMIC

RETROFIT

524 Main Street, Suite 2, Oregon City, Oregon 97045 | 503-659-2205

PR

EL

IM

IN

AR

Y

D

ES

IG

N

FEB. 2022

MRS

MEG

P-2615-21

REVISION ID: DATE:

-P

RELIM

IN

ARY-

NOT FOR C

ONSTRUCTIO

N

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EXPIRES: 06-30-22

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AREA A & B ROOF FRAMING PLAN

3/32"= 1'-0"

S2.1

KEY PLAN

NTS

S2.1

AREA

A

AREA

C

AREA

D

AREA

F

AREA

E

AREA B

AREA

G

S8

S8

S1, S2, S3, S4, S5

S2, N2

N6, N7 S6B S1, S3, S4, S5

S6C

S3

S8

S1, S6A

S9

S10

N8S1, S3, S4, S5N8

S6BS1, S3, S4, S5

N8

S9 S1, S6A

S1, S6A

S7 S8

N8

N6, N7

S3

S1

S1

S1

S1

S1

S1

S1

S2.1

AREA A & B ROOF

FRAMING PLAN

PROJECT NO:

DRAWN:

CHECKED:

DATE:

O N

E

IN

C H

E Q

U

AL

S

FU

LL

S

C

AL

E

MOUNT ANGEL SCHOOL

DISTRICT 91

730 E. MARQUAM ST.

MOUNT ANGEL, OR 97362

MOUNT ANGEL

MIDDLE SCHOOL

GYM SEISMIC

RETROFIT

524 Main Street, Suite 2, Oregon City, Oregon 97045 | 503-659-2205

PR

EL

IM

IN

AR

Y

D

ES

IG

N

FEB. 2022

MRS

MEG

P-2615-21

REVISION ID: DATE:

-P

RELIM

IN

ARY-

NOT FOR C

ONSTRUCTIO

N

AutoCAD SHX Text

EXPIRES: 06-30-22

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Appendix D:

Geotechnical Information

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1, March 28, 2014 5551-A GEOTECHNICAL RPT

Mt. Angel School District c/o HMK CO 890 E. Marquam Street Mt. Angel, OR 97362

Attention: Chris McKay

SUBJECT: Geotechnical Investigation and Site-Specific Seismic Hazard Study Mt. Angel Middle School Improvements Mt. Angel, Oregon

At your request, GRI has completed a geotechnical investigation and site-specific seismic hazard study for proposed improvements to Mt. Angel Middle School at 460 East Marquam Street in Mt. Angel, Oregon.

The Vicinity Map, Figure 1, shows the general location of the site. The purpose of our investigation was to evaluate subsurface conditions at the site and develop conclusions and recommendations for earthwork, excavation, and design and construction of foundations and pavements for the proposed improvements.

The investigation included subsurface explorations, laboratory testing, and engineering analyses. This report describes the work accomplished and provides our conclusions and recommendations for use in design and construction of the improvements.

PROJECT DESCRIPTION

The existing Mt. Angel Middle School and surrounding improvements are shown on the Site Plan, Figure

2. The school campus consists of several one-story buildings, parking lots, driveways, and athletic facilities. Proposed improvements will include removal of the existing bus loop/driveway and attached parking stalls. A new parking lot and reconfigured bus loop/driveway will be constructed using asphaltic-concrete (AC) pavement east of the middle school, where the existing bus loop is located. New Portland cement concrete (PCC) pavement will be used to construct a driveway apron from E. Marquam Street and sidewalks surrounding the new bus loop and parking lot. Based on discussions with BLRB Architects, we understand the new pavements will be subjected to about five bus trips per day per lane over a 9-month school year.

At this time, plans for reconfiguration and remodel of existing school buildings are unknown.

Recommendations for design and construction of foundations are included to assist with planning for future improvements at the school. We anticipate future improvements will consist of one-story, relatively lightly loaded structures with maximum column loads of about 50 kips and maximum wall loads of about 4 kips/ft. We understand stormwater runoff from the improvement area will discharge into the City of Mt.

Angel sewer system, and on-site infiltration will not be necessary. We anticipate cuts and fills to establish site grades will be minimal.

SITE DESCRIPTION

Surface Conditions and Topography

Based on review of available information and our observations at the site, the ground surface at the campus has a gentle slope from about elevation 200 ft along the eastern property boundary to elevation 190 ft along the western property boundary. The campus is bordered by E Marquam Street on the south, single-family residences on the west, the Mt. Angel School District’s solar power facility on the north, and sports fields associated with the Mt. Angel School District to the east. The existing school building occupies the majority of the property and is located near the northeastern property boundary. Landscaped areas are present along the western and southern property margins, and AC driveways and parking areas are located east of the school.

GRI observed site conditions on March 5, 2014. The existing AC pavements in the bus loop/driveway appeared to be in poor condition with frequent fatigue (alligator), longitudinal and transverse cracks, and areas with significant surface wear. The pavement in the parking stalls attached to the bus loop appear to be in fair condition with minor surface wear and intermittent longitudinal and transverse cracks. No potholes or indications of surface raveling were observed.

Geologic Setting

The site is mantled with alluvial soils referred to as Willamette Silt. In general, Willamette Silt is composed of unconsolidated beds and lenses of fine-grained sand, silt, and clay. Stratification within this formation commonly consists of 4- to 6-in.-thick beds, although 2- to 4-ft-thick beds are present locally. In some areas the silt is massive, and bedding is indistinct or non-existent. The Willamette Silt is underlain by coarser-grained alluvial valley fill deposits, which are in turn underlain by volcanic rocks of the Columbia River Basalt Group.

The site is located less than 1 km northeast of the Mt. Angel Fault, which is a northwest-striking fault that has been relatively active and has been identified as the likely source for the 1993 Scotts Mills earthquake and a series of earthquake swarms that occurred near Woodburn in 1990 (Personius, 2002).

SUBSURFACE CONDITIONS

General

GRI investigated subsurface materials and conditions at the site on March 5, 2014, with four borings, designated B-1 through B-4. The borings were advanced to depths of 11.5 to 40.4 ft at the approximate locations shown on Figure 2. The field exploration and laboratory testing programs completed for this investigation are described in Appendix A. Logs of the borings are shown on Figures 1A through 4A. The terms used to describe the materials encountered in the borings are defined on Table 1A.

Soil

For the purpose of discussion, the materials disclosed by the explorations have been grouped into the following major units based on their physical characteristics and engineering properties.

1. AC PAVEMENT

2. SILT and CLAY

3. SAND

4. GRAVEL

The following paragraphs provide a detailed description of the soil units and a discussion of the groundwater conditions at the site.

1. AC PAVEMENT. Borings B-3 and B-4 were advanced in existing paved areas and encountered about

3.5 in. of AC pavement at the ground surface. The pavement is underlain by about 6.5 in of crushed rock base (CRB) course.

2. SILT and CLAY. Beneath the pavement section in borings B-3 and B-4 and at the ground surface elsewhere on the site, the borings disclosed layered silt and clay soils that extend to a depth of about 27 ft in deeper borings B-1 and B-2. The silt contains varying percentages of clay, ranging from some clay to clayey, and the clay contains varying percentages of silt, ranging from some silt to silty. The soils are generally brown to gray with varying degrees of rust and gray mottling and contain a trace to some fine-grained sand. The zone of clay soil encountered at a depth of about 15 to 17 ft in borings B-1 through B-3 contains fine- to medium-grained sand and scattered fine gravel. The relative consistency of the soils is typically medium stiff to stiff based on N-values 4 to 24 blows/ft; however, N-values of 0 to 3 blows/ft disclosed a zone of very soft to soft silt between a depth of about 7.5 and 10 ft in borings B-1, B-3, and B-4.

The natural moisture content of the soils ranges from about 30 to 50%. Atterberg limit testing indicates the soil has a liquid limit of 36 to 67% and plasticity index of 14 to 43%. Boring B-3 was terminated in clay at a depth of 21.5 ft, and boring B-4 was terminated in silt at a depth of 11.5 ft.

3. SAND. Sand was encountered beneath a layer of clayey silt at a depth of about 27 ft in borings B-1 and B-2 and extends to depths of about 32 to 34 ft. The sand is typically dark brown, fine to coarse grained, and contains some silt and scattered subangular to subrounded gravel. N-values ranging from 33 to 52 blows/ft indicate the relative density of the sand is dense to very dense. The natural moisture content of the sand ranges from about 19 to 29%.

4. GRAVEL. Gravel was encountered in borings B-1 and B-2 at a depth of 34 and 31.5 ft, respectively, and extends to the bottom of the explorations. The gravel is typically subangular to subrounded and has a matrix of brown, silty sand. N-values of more than 50 blows for 6 in. of sampler penetration (defined as practical refusal) indicate the relative density of the gravel is very dense. Scattered cobbles were noted below a depth of about 37 ft in boring B-1.

Groundwater

Borings B-1 and B-2 were completed using mud-rotary drilling techniques, which does not allow the measurement of groundwater levels. Groundwater was not observed in borings B-3 and B-4, which were completed using hollow-stem auger techniques. On March 18, 2014, groundwater was measured at a depth of about 5 ft in an observation standpipe installed by GRI at John F. Kennedy High School. We anticipate the groundwater level typically occurs below a depth of 10 ft during the normal, dry summer and fall months and can approach the ground surface during the wet, winter and spring months or during periods of heavy or prolonged precipitation.

CONCLUSIONS AND RECOMMENDATIONS

General

Subsurface explorations for this investigation disclosed the site is mantled with silt and clay soils that are underlain by a 5- to 7-ft-thick layer of sand overlying gravel that extends to a depth of 40 ft, the maximum depth explored. Our observation of the existing AC pavement indicates the bus loop/driveway pavement is in poor condition, and the attached parking stalls pavement is in fair condition.

The primary geotechnical consideration associated with construction of the proposed improvements is the presence of near-surface fine-grained soils, which are extremely sensitive to moisture content for proper compaction. Careful working procedures and the use of imported granular fill material may be necessary if site preparation and grading are undertaken during wet weather and wet ground conditions. The following sections of this report provide our conclusions and recommendations for design and construction of the proposed improvements.

Site Preparation and Grading

As previously mentioned, the existing bus loop/driveway and parking lot pavement will be removed for construction of the new parking lot and reconfigured bus loop/driveway. At the time of field explorations, a geotextile fabric was not encountered beneath the pavement section, and it appeared the existing CRB was contaminated by the underlying silt and clay subgrade. It is recommended that the existing pavement section be removed to firm subgrade soil. In addition, any organic soils within the limits of new pavement areas should also be removed. Upon completion of pavement removal, the exposed subgrade should be observed by a qualified geotechnical engineer. Areas of soft subgrade, unsuitable fill, or otherwise unsuitable materials should be overexcavated to firm soil and backfilled with structural fill.

Due to the moisture-sensitive nature of the fine-grained soils, site preparation and earthwork phases of this project should be accomplished during the dry, summer months, typically extending from June to mid- October. The contractor must employ construction techniques that prevent or minimize disturbance and softening of the subgrade soils. The use of scrapers for stripping and earthwork, even during dry weather, may result in subgrade disturbance. As an alternative, a bulldozer or a trackhoe equipped with a smooth-edged bucket could be used for stripping and excavation.

To prevent disturbance and softening of the subgrade soils during wet weather or ground conditions, movement of construction traffic should be limited to granular haul roads and work pads. In general, a minimum of 18 to 24 in. of relatively clean, granular material is required to support concentrated construction traffic, such as dump trucks and concrete trucks, and protect the subgrade. A 12-in.-thick granular work pad should be sufficient to support occasional light truck traffic and low-volume construction operations. A woven geotextile separation fabric should be placed on the exposed subgrade prior to placement and compaction of the granular work pad to improve the performance of work pads and haul roads.

If the subgrade is disturbed during construction, soft disturbed soils should be overexcavated to firm soil and backfilled with granular structural fill.

Structural Fill

It is anticipated that only a relatively minor amount of structural fill will be required to establish finish elevations of building and paved areas. In our opinion, imported granular material would be most suitable for construction of the structural fills. Granular material, such as sand, sandy gravel, or fragmental rock with a maximum size of about 11/2 in. would be suitable structural fill material. The majority of on-site materials will not be suitable for use as structural fill. Granular fill should be relatively clean and have less than about 5% passing the No. 200 sieve (washed analysis). Granular fill should be placed in 12-in.-thick (loose) lifts and compacted with a vibratory roller to at least 95% of the maximum dry density as determined by ASTM D 698, or until well keyed. Fill placed in landscaped areas should be compacted to a minimum of about 90% of ASTM D 698.

All backfill placed in utility trench excavations within the limits of walkways, paved areas, and other structural improvements, should consist of granular structural fill as described above. The granular backfill should be compacted to at least 95% of the aforementioned standard. Flooding or jetting the backfilled trenches with water to achieve the recommended compaction should not be permitted.

Excavation and Shoring

General. We anticipate excavations to construct new foundation systems will be minimal. In the event that new foundation systems will be embedded more than 4 ft below existing grades, or constructed in close proximity to existing foundations or structures, a combination of temporary excavation slopes and/or shoring may be used to complete the excavation.

The method of excavation and design of excavation support are the responsibility of the subcontractor and should conform to applicable local, state, or federal regulations. The information provided below is for the use of our client and should not be interpreted to mean that we are assuming responsibility for the subcontractor’s actions or site safety.

Temporary Excavations. Temporary excavations can be made by sloping the excavation sidewalls at about 1H:1V or flatter. It should be understood the steeper the temporary slopes, the more risk there is of sloughing of the exposed surface during construction. In our opinion, the short-term stability of temporary slopes will be adequate if surcharge loads due to construction traffic, vehicle parking, material lay down, etc., are not allowed within 10 ft of the top of the cut. Other measures that should be implemented to reduce the risk of localized failures of temporary slopes include (1) use geotextile fabric to protect the exposed cut slopes from surface erosion; (2) provide positive drainage away from the top and bottom of the cut slopes; (3) construct and backfill walls as soon as practical after completing the excavation; and

(4) periodically monitor the area around the top of the excavation for evidence of ground cracking. It must be emphasized that following these recommendations will not guarantee that sloughing or movement of the temporary cut slopes will not occur; however, the measures should serve to reduce the risk of a major…