AIA Continuing Education

Transcription

1 AIA Continuing Education Hall & Company is a Registered Provider with the American Institute of Architects Continuing Education Systems. Credit earned based on the completion of this program will be reported to AIA/CES for AIA Members. Please send your AIA member number to kbernal@hallandcompany.com after the presentation for reporting. This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement for the AIA of any material of construction or any method or manner of handling,using, distributing, or dealing in any material or product. Questions related to the specific materials, methods, and services will addressed at the conclusion of this presentation. 1

2 OVERVIEW Introduction to Gabions Project Description System Design vs. Construction System Failure Description Failure Analysis Lessons Learned Copyright Lowe Consulting, LLC 2015 EROSION CONTROL GABIONS Wire baskets filled with rocks Baskets wired together to provide erosion resistant surface Twisted or welded wire options Plain steel, galvanized steel, PVC coated wire or fuse bonded PVC powder coating, stainless steel In Use Since 1520 ELEMENTS OF AN EROSION CONTROL GABION SYSTEM Compacted Subgrade Filter Fabric Wire Baskets Rocks Filling Baskets 2

3 GABION SUPPLIERS Maccaferri (Founded 1879) Modular Gabion Systems TerraAqua, Inc. Design Assistance Available 3

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7 CLIENT/PROJECT Governmental Agency Location Coastal SE Georgia Drainage for large (10,000 Ac.) site Engineer responsible for design only Engineer available for support during construction BACKGROUND Major outfall channels, bridges, and water control structures required erosion control Gabions Selected Excellent performance elsewhere Competitive cost Client stated preference 7

8 INITIAL PROBLEM Construction completed - June 1984 Problem Identified - September 1985 Railroad bridge abutment partially exposed Partial Collapse of gabions 8

9 ANALYSIS Client agreed to pay for above-ground investigation if design found not deficient ANALYSIS (cont d.) Report prepared documenting construction variance from design Report supported sufficiency of design and improper construction Client rejects report findings Files A/E liability claim 9

10 SUBSEQUENT PROBLEM December 1987 Soil beneath gabion protected upstream channel was displaced beneath gabions into receiving channel, bulging receiving channel gabions up Major collapse of gabion system September 1985 December

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12 FURTHER INVESTIGATION Client Authorizes Design of Repair Below-Ground Investigation Occurs 12

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16 CONCLUSIONS Gabion System Failure Caused by: Inadequate or improper clearing and grubbing Inadequate or improper compaction of soil beneath gabions Failure to construct to lines and grades required by contact documents CONCLUSIONS (Cont d) Use of earth reinforcing geotextile instead of specification required filter fabric Use of second layer of earth reinforcing geotextile Inadequate construction monitoring Failure to involve design engineer during construction 16

17 CLAIM RESOLUTION Report prepared presenting incontrovertible evidence of construction deficiency Client drops A/E claim CHRONOLOGY Design Accepted Mar 83 Construction Completed Jun 84 Initial Problem Identified Jul 85 Above-Ground Visual Inspection Sept 85 Investigation Authorized Sept 85 Report Submitted Jan 86 A/E Liability Claim Jul 86 Client Encouraged to Fix Mar 87 CHRONOLOGY (Cont d.) Client Encouraged to Fix Jul 87 Subsequent Problem Identified Dec 87 Engineer Authorized to Design Fix Dec 87 Detailed, Below-Ground Investigation Jan 88 Report of Findings Feb 88 Liability Claim Dropped Jun 88 17

18 LESSONS LEARNED Divert stormwater away from structures Specify filter fabric carefully Remind Client to verify filter fabric Involve manufacturer s representative during design and construction Be involved in construction LESSONS LEARNED (Cont d) Develop report exhibits As you go Document, Document, Document MANAGING PROFESSIONAL LIABILITY CLAIMS Notify your management, professional liability broker, and corporate attorney at the first hint of a pending claim Develop a defense strategy Be proactive let the client know that solving the problem is your top priority Understand the client s professional liability claim procedure Investigate the cause of the claim 18

19 MANAGING PROFESSIONAL LIABILITY CLAIMS (cont d.) Ask for information that you need to support your defense Be thorough - dig-it-up Document, Document, Document The faintest of ink is more powerful than the strongest memory Old Chinese Proverb Be fair minded willing to compromise Pursue settlement rather than litigation To report your attendance to AIA, please kbernal@hallandcompany.com 19