PURCHASING DEPARTMENT COLEEN CASELLA

Assistant Purchasing Agent for

Goods & Services

Elizabeth Unger NATALIE SULLIVAN Purchasing Agent Assistant Purchasing Agent for

Design & Construction

City of Cambridge

795 Massachusetts Avenue, Cambridge, Massachusetts 02139 Voice: 617-349-4310 Fax: 617-349-4008 TTY: 617.349.4242

TO: All Bidders

FROM: City of Cambridge

DATE: July 28, 2020

RE: File No. 9204 – Inman Square Firehouse Structural Repair - Addendum No. 2

This addendum is comprised of:

1. Attendee list from pre-bid

2. Questions and Answers

3. Changes to drawings

Attendee list from pre-bid meeting:

Mark Lareau (mlareau@contractingspecialists.com), CSI Contracting Specialists

Mark Moruso (epbbuilders@gmail.com), EPB Inc

Stephen Locke (slocke@landlcontracting.com), L&L Contracting Inc

Anonymous (no name on business card, ncc@northencontractingcorp.com), Northern

Contracting Corp

Andrew McInnis (andrewm@mcicontracting.com), MCI Contracting

Mike Legee (mlegee@pjspillane.com), P.J. Spillane

Rob Juusola – City of Cambridge

Laura Wardek - ARUP

The following question was asked and answered:

Question: Upon reviewing the plans and specifications I found a note in Section 051200

Structural Steel Framing.

The Architect States that the Fabricator & Erector must be an AISC Certified Shop & Erector.

Since this is A small project. Can this Certification be Waived?

Answer: This can be waived subject to the Fabricator demonstrating that all welders working on

the project are AWS (American Welding Society) certified as required by section 1.5 F of the

Section 051200 Structural Steel Framing Specification.

795 Massachusetts Avenue, Cambridge, Massachusetts 02139 Voice: 617-349-4310 Fax: 617-349-4008 TTY: 617.349.4242

Question: Could you please provide a drawing or quantity for the traffic coating area?

Answer: Please see revised drawing S4.01 for required traffic coating extents.

Question: Could you please provide a drawing on quantity for the 5% of area that will

require surface patching?

Answer: Refer to sheet S4.01 – 5% allowance refers to entire first floor area

Question: Could you provide a detail to clarify what the remove and reinstall for the 6

existing drains and where they are located?

Answer: Please see revised drawing S4.01 – this note has been removed and replaced with detail

4 on S7.01, requiring small areas of breakout and mortar patching around each existing drain

regardless of slab condition, to allow proper sealing around the drains. This is in addition to the

5% slab area allowance.

Question: We were unaware there was a walkthrough last week. Is there any way we would be

able to have a site visit this week?

Answer: The pre-bid walkthrough was Wednesday July 22 at 10am as stated in the Bid

Documents. No additional site visits will be scheduled.

Question: General Conditions specify insurance requiring pollution liability of 3 mil general

aggregate and general liability of 15 mil general aggregate these levels seem excessive for project

will they be required?

Answer: Please see section 8.10.1. “The City reserves the right, at its sole discretion, to amend

the insurance requirements contained herein.”

Changes to the drawings:

REVISED SHEET S4.01 – STRUCTURAL FIRST FLOOR FRAMING PLAN

REVISED SHEET S7.01 – STRUCTURAL TYPICAL DETAILS

All other details remain the same.

Elizabeth Unger

Purchasing Agent Addendum No. 2

1

A

B

C

D

2 3 4 5 6 7

16' - 4" 13' - 6" 13' - 6" 13' - 6" 13' - 6" 13' - 11"

13' -

4"

13' -

4"

13' -

6"

2S7.01

SINGLE DIAGONAL HATCHED AREA INDICATES EXTENT OFORIGINAL FRAMED CONCRETE REINFORCED SLAB ONBEAMS. THE INTERVENTIONS SHOWN IN THESE PLANSARE A MEDIUM-TERM SOLUTION (APPROXIMATELY 10-20YEARS). THE LONG TERM SOLUTION IN THIS AREA WILLREQUIRE REMOVING AND REPLACING THE ENTIRE SLABIN THIS BAY. REPLACING THE SLAB IS NOT IN THE SCOPEOF THESE CONTRACT DOCUMENTS.

3S7.01

PROVIDE LOCAL REMOVAL AND REINSTATEMENTOF SLAB AROUND ALL (E) DRAIN PENETRATIONSTO FACILIAITE NEW TRAFFIC COATING, REF 4|S7.01.ASSUME 6 EXISTING DRAIN LOCATIONS.

DIAGONAL CROSS HATCHING INDICATES APPROXIMATE AREAS OF REQUIREDUNDERSLAB REPAIR ZONES BASED ON VISUALLY OBSERVED DAMAGE; FOR

ESTIMATING PURPOSES ASSUME AREAS SHOWN ON PLAN FOR REPAIR. FINALLOCATIONS TO BE VERIFIED WITH ENGINEER PRIOR TO PROCEEDING WITH REPAIRS.

TYPICALUNDERSIDEREPAIRDETAIL

PRIOR TO REPAIRS, REMOVECONCRETE LAYER AROUND 12" LONG

SEGMENT OF STEEL BEAM ANDCOORDIANTE WITH ENGINEER FOR

ASSESSMENT/MEASUREMENT OFREMAINING STEEL SECTION; REPAIR

AFTER WITH MATCHINGLIGHTWEIGHT CONCRETE WITH

REPAIR PINS TO HOLD IN PLACE; (2)LOCATIONS IN VAULT ROOM

PRIOR TO REPAIRS, REMOVE CONCRETELAYER AROUND 12" LONG SEGMENT OFSTEEL BEAM AND COORDIANTE WITHENGINEER FOR ASSESSMENT/MEASUREMENTOF REMAINING STEEL SECTION; REPAIRAFTER WITH MATCHING LIGHTWEIGHTCONCRETE WITH REPAIR PINS TO HOLD INPLACE; (2) LOCATIONS IN MAIN ROOM

TYPICAL SHORINGBEAM ASSEMBLY

2S7.01

TYPICAL SHORINGBEAM ASSEMBLY

IN ALL GARAGE BAYS ASSUME 5% OF AREATO BE SURFACE PATCHED WITH REPAIRMORTAR, CRACKS FILLED WITH EPOXYSEALANT, AND LEVELLED FOR APPLICATIONOF WATER AND CHLORIDE RESISTANTTRAFFIC COATING BY CONTRACTOR

DASHED LINE DENOTES EXTENT OF NEW TRAFFICCOATING REQUIRED: CONTINUE INTO REVEALS OFGARAGE DOORS AND BACK TO TOP OF RAMPSWITHIN FIRE APPLIANCE BAYS. EXTEND BACK TOEXTERNAL ACCESS DOOR IN ELECTRICAL DEPTBAY, BUT NO RELOCATION OF ELECTRICAL DEPTWORKBENCHES REQD (ALIGN COATING EDGE TOLAST GARAGE DOOR)

1

1

1

www.arup.com

Architect

Drawing Title

Scale

Drawing Status

Job Number

Drawing Number

Issue

Date

Sheet

CITY OF CAMBRIDGEDEPT. OF PUBLIC WORKS

Client

Project Title

Project No.

Project Address

Arup USA Inc.60 State Street.10th FloorBoston, MA 02109T +1 617 864 2987 F +1 617 864 6178

FILE NO. 9204

NOT FORCONSTRUCTION

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STRUCTURAL FIRSTFLOOR FRAMINGPLAN

BID SET

273686-10

S4.017/16/2020

INMAN SQUAREFIREHOUSESTRUCTURAL REPAIR

1384 Cambridge Street,Cambridge, MA 02139

1/4" = 1'-0"FIRST FLOOR FRAMING PLAN1

NOTES:1. LOCATION OF SHORING ASSEMBLIES TO BE INSTALLED DENOTED BY:2. QUANTITY AND LOCATIONS OF REPAIRS SHOWN ARE INDICATIVE.

EXACT QUANTITY AND LOCATIONS TO BE DETERMINED IN FIELD INCONJUNCTION WITH ENGINEER.

3. FOR ESTIMATING PURPOSES, ASSUME NUMBER AND LOCATIONSHOWN ON THIS PLAN. NOTE THAT EACH DASH DOTTED LINEREPRENTING AN ASSEMBLY INCLUDES ONE PAIR OF BACK TO BACKCHANNELS AND ASSOCATED CONNECTIONS AT EACH END.

4. SLAB SHALL BE UNLOADED DURING INSTALLATION OF SHORINGASSEMBLIES AND UNDERSIDE REPAIRS - NO TRUCKS OR OTHERSIGNIFICANT LOADS SHALL BE PRESENT UNTIL ALL REPAIR WORK ISCOMPLETED

Issue Date Description

1 07/28/2020 Addendum #2

EXISTING CONCRETE SLAB

EXISTING 22GA METAL DECK

EXISTING I-BEAM

NEW MC8X8.5 A36 TYP

NEW 3" WIDE X 1 1/4" DEEP SOLID BAR A529GR 50 TYP

1/2" 1 1/2" 3" 1 1/2" 4 1/2" MAX 1" MIN

NEW 5/16" THICK PLATE A529 GR 50 TYP

(4) 3/4" A325 BOLTS PER CHANNELREFER TO NOTE 4

1S7.01

3"

APPLY EPOXY COATING TO SEAL TOPSURFACE OF (E) CONCRETE SLAB - SIKADUR22 LO-MOD OR APPROVED EQUAL

EXISTING CONCRETE SLAB

EXISTING 22GA METAL DECK

EXISTING I-BEAM

NEW 5/16" THICK PLATE A529 GR 50 TYP

NEW MC8X8.5 A36 TYP

NEW 3" WIDE X 1 1/4" DEEP SOLID BAR A529GR 50 TYP

NOTES:1. INSTALL SHORING ASSEMBLIES IN EVERY OTHER FLUTE OF METAL DECK AS REQUIRED TO SUPPORT THE AREA OF DETERIORATED SLAB.2. STAGGER ASSEMBLIES IF SHORING IS REQUIRED ON BOTH SIDES OF I-BEAM.3. ASSEMBLIES MAY BE OFFSET BY ONE ADDITIONAL FLUTE TO AVOID HANGERS FOR (E) SERVICES. NOTIFY ENGINEER IF LARGER OBSTRUCTION ENCOUNTERED.4. VERIFY DIMENSIONS OF EXISTING COMPONENTS IN FIELD PRIOR TO FABRICATION. NOTIFY ENGINEER IF DIMENSIONS SHOWN ARE INCORRECT.5. IN LIEU OF PROVIDING (8) BOLTS AT THE END OF EACH ASSEMBLY, (4) THRU BOLTS MAY BE USED. IF (4) THRU BOLTS ARE USED, PROVIDE (4) HSS2.375X0.250 ROUND TUBES A500 GR B BETWEEN PLATES AT THE

LOCATION OF EACH BOLT. HSS ELEMENTS CAN BE TACKED IN PLACE OR SHIPPED LOOSE AND PLACED IN FIELD.6. ALL STEEL SHALL BE HOT-DIP GALVANIZED, WITH CEMENTITIOUS FIREPROOFING APPLIED AFTER INSTALLATION.

12" +/-

0' - 4" +/-0' - 2" +/-

2 1/

2"3"

2 1/

2"

(4) 3/4" A325 BOLTS PER CHANNEL

REFER TO NOTE 4

1/4 1/2"

RET ONBACK OFPLATE TYP

1/4TYP

REFER TO NOTE 2

DRY PACK OR SHIM AS REQUIRED FORCONTACT

APPLY EPOXY COATING TO SEAL TOPSURFACE OF (E) CONCRETE SLAB - SIKADUR22 LO-MOD OR APPROVED EQUAL

EXISTING CONCRETE SLAB

APPLY EPOXY COATING TO SEAL TOPSURFACE OF (E) CONCRETE SLAB - SIKADUR22 LO-MOD OR APPROVED EQUAL

CUT BACK TO SOUND CONCRETE ATLEAST 1" BEYOND EXISTING REBAR ANDROUGHEN TO 1" AMPLITUDE

CLEAN RUST FROM REBAR AND APPLY BONDING PRIMERWITH CORROSION INHIBITOR TO EXPOSED SURFACE

CONCRETE PATCH REPAIR PINS DRILLED AND EPOXYANCHORED ACROSS INTERFACE AT MAX 10" SPACING

EXPOSE AT LEAST 18" OF UNDAMAGEDREBAR BEYOND DAMAGED ZONE TO ALLOWFOR SPLICE WITH NEW REBAR OR EXTENDNEW REBAR TO FACE OF EXISTING BEAM ANDDRILL AND EPOXY INTO SUPPORTING BEAMZONE ABOVE AT 45 DEGREE ANGLE

NEW REBAR SHALL MAKE UP FORLOSS OF EXISTING REBARPERCENTAGE. NOTIFY ENGINEERWHEN EXISTING REBAR FULLYEXPOSED FOR FIELD MEASUREMENTAND DETERMINATION OFSUPPLEMENTAL REBAR SIZE. FORESTIMATING PURPOSES ASSUME #4@12" NEW REBARS ACROSS ALLZONES OF REPAIR

TENSION DEVELOPMENT SPLICEOF NEW REPAIR REBARS ASREQ'D IF BARS CANNOT BEINSTALLED CONTINUOUSLYACROSS ZONE OF REPAIR

SPAN DIRECTION OF EXISTING CONCRETE SLAB

EXISTING STEEL BEAM ANDCONCRETE ENCASEMENT

INFILL WITH OVERHEAD REPAIR MORTARTO ORIGINAL SLAB THICKNESS

INSTALLATION PROCEDURE:1. CHIP OUT EXISTING CONCRETE 1/2" TO 3/4" DOWN, TAPERING 3" TO 6" AWAY FROM DRAIN BODY.2. FILL WITH EPOXY MORTAR3. PLACE TRAFFIC COATING TO TOP OF DRAIN. PROVIDE SEALANT AT EDGE OF DRAIN, OR OTHER INTERFACE DETAILS AS REQUIRED BY TRAFFIC COATING MANUFACTURER TO SEAL AT DRAIN BODY.

1/2" TO 3/4"

NEW EPOXY MORTAR

NEW TRAFFIC COATING

EXISTING CONCRETE SLAB

www.arup.com

Architect

Drawing Title

Scale

Drawing Status

Job Number

Drawing Number

Issue

Date

Sheet

CITY OF CAMBRIDGEDEPT. OF PUBLIC WORKS

Client

Project Title

Project No.

Project Address

Arup USA Inc.60 State Street.10th FloorBoston, MA 02109T +1 617 864 2987 F +1 617 864 6178

FILE NO. 9204

NOT FORCONSTRUCTION

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STRUCTURALTYPICAL DETAILSSHEET 1

BID SET

273686-10

S7.017/16/2020

INMAN SQUAREFIREHOUSESTRUCTURAL REPAIR

1384 Cambridge Street,Cambridge, MA 02139

3" = 1'-0"TYPICAL SLAB ON METAL DECK SHORING DETAIL - PROFILE2

3" = 1'-0"TYPICAL SLAB ON METAL DECK SHORING DETAIL - SECTION1

3" = 1'-0"TYPICAL FLAT SLAB UNDERSIDE REPAIR3

Issue Date Description

1 07/28/2020 Addendum #2

6" = 1'-0"TYPICAL REPAIR AT EXISTING FLOOR DRAINS4

1