Fracasos de Obras Falsas en Puentes

7/24/2019 Fracasos de Obras Falsas en Puentes

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Bridge Falsework Forum-

Welcome & Introduction

Dolores Valls, P.E.

Deputy Division Chief

Offices of Structure Construction


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Welcome & Introduction

Introduction of Key Participants Purpose of Forum

Notes & Action Items


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Introductions- Key Participants

Facilitator Mike Halverson Falsework Manager John Babcock

OSC F/W Senior Engineers: North = John Walters

South = Ken Burkle

OSC F/W Technical Team

CT/Industry Joint F/W Advisory Team


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Falsework Forum - Purpose

High Risk F/W Operation: Contractors, OSC, public

Joint Responsibility for public safety

High profile incident new definition

Time to discuss:

Best Management Practices

Revised Specifications?


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Falsework Forum Notes

Action Items will be captured All notes will be posted on Internet

http://www.dot.ca.gov/hq/esc/construction/construc.htm

Division of Engineering Services

Structure Construction


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PROGRESSION OF MEETINGS

RELATED TO FALSEWORK

STABILITY

(John Babcock)

INTERNAL FALSEWORK TEAM

JOINT CALTRANS/INDUSTRY

FALSEWORK ADVISORY TEAM


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Bridge Falsework Forum

Series of three meetings to addressfalsework stability


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Offices of Structure Construction TechnicalTeam, Falsework

Issues Identified

Solutions suggested


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Joint Caltrans / Industry FalseworkAdvisory Team Issues Identified

Solutions recommended


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INTRODUCTIONS


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Agenda REGISTRATION

FORUM INTRODUCTION (Dolores Valls)

INTRODUCTIONS

PROGRESSION OF MEETINGS (John Babcock)

BACKGROUND

ADVISORY TEAM RECOMMENDATIONS

FALSEWORK STABILITY TRAFFIC OPENING REQUIREMENTS

COMMUNICATION/PARTNERING/FALSEWORK DESIGN

PLANS

FALSEWORK ENGINEER PRESENCES AND APPROVALS BEST PRACTICES (Internal by Contractor)

REWRITE FALSEWORK MANUAL, BRIDGE

CONSTRUCTION MEMOS, SPECIFICATIONS


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Agenda

ADVISORY TEAM RECOMMENDATIONSWINCHES FOR FALSEWORK REMOVAL


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FALSEWORK SUBMITTALS3 0 4

1 0 5

1 7 4

9 5

4 2

9 41 0 4

4 4

1 0 8

1 2 6

6 0

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

1 9 9 7 1 9 9 8 1 9 9 9 2 0 0 0 2 0 0 1 2 0 0 2 2 0 0 3 2 0 0 4 2 0 0 5 2 0 0 6 2 0 0 7

Year

Submittals


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MAJOR FALSEWORKINCIDENTS

1 1

2

3

0 0

3

1

0

3

1

0

2

4

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year

MajorIncident


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FALSEWORK STABILITY


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FALSEWORK STABILITY


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FALSEWORK STABILITY


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FALSEWORK STABILITY


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CASE 1


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Falsework Elevation View

121 123122

Not attached

per plan

Contractor grading Bent at time of incident.Contractor grading Bent at time of incident.


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Falsework Bent Elevation

W24 X 131

CenterlineBent 123

Cable Bracing

Cripple Cap


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CASE 1


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CASE 2


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CASE 2


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CASE 2


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CASE 3


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CASE 3


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CASE 3


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CASE 3


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CASE 3


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LESSONS LEARNED

Stability measures must be in place at all times Multi-tiered systems require special attention Dont adjust falsework over or adjacent to

traffic

34


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DONT ADJUST

FALSEWORK OVER OR

ADJACENT TO TRAFFIC

Contract Special Provisions Maintaining Traffic


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HOW DO WE MAINTAIN FALSEWORKSTABILITY?

Or

WHAT IS IT THAT CAUSESFALSEWORK TO BECOME UNSTABLE?


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ADVISORY TEAM

RECOMMENDATIONS -

STABILITY


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1. Traffic Opening requirements

1.1 Independently stable/ stand aloneframes

1.2 Connection criteria

1.3 Customary to increase load withincreased risk

1.4 Continuity between structure columns

1.5 Implementation:

1.5.1 Falsework Manual

1.5.2 Specifications


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2. Communication/Partnering/Falsework Design Plans

2.1 Require meetings at criticalbenchmarks

2.1.1 Erection

2.1.2 Grading

2.1.3 Removal

2.1.4 Prior to opening to traffic (forfalsework over traffic)


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2. Communication/Partnering/Falsework Design Plans

2.2 Erection and Removal Plans2.2.1 General at time of falsework plan

submittal

2.2.2 Detailed at pre-activity meeting

2.3 Implementation


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3. Falsework Engineer of RecordPresence and Approvals

3.1 At Critical benchmarks3.1.1 Certify prior to traffic opening (for

falsework over traffic)

3.1.2 Onsite during grading operations

3.1.3 Progressive stages of construction

3.2 Implementation


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4. Best Practices(Internal by Contractor)

4.1 Training4.2 Company Certification

4.3 Implementation

5 R i F l k M l


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5. Rewrite Falsework Manual,

Bridge Construction Memos,Specifications

5.1 Longitudinal Stability Analysis

5.2 Friction Transfer Capacity (FTC)

Allowance

5.3 Testing and use of clamps


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WINCHES FOR

FALSEWORK

REMOVAL


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WINCHES FOR FALSEWORK REMOVAL

Traffic window limitations

Operation cannot be reasonably doneotherwise

Does not encroach upon the vertical

and horizontal traffic clearances


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WINCHES FOR FALSEWORK REMOVAL

Will not cause a traffic disruptionWork is performed at night with a

closure

Load is static to structure soffit


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Winches for Falsework Removal


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1. Redundant systems are used

1.1 Use High Strength rods or strands

and winches

1.2 High strength rods or strands1.2.1 Requires redundant system

1.2.2 Requires use of new strand


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1.3 Winches only

1.3.1 Safety factor (5:1)

1.3.2 Certification

1.4 Inspection of critical elements (NDT)


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2. Implementation

2.1 Provide additional direction

2.2 Update Falsework Manual


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Discussion


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Adjourn

Documents

Fracasos de Obras Falsas en Puentes