HomeMy WebLinkAboutMATERIAL DISTRIBUTED TO THE CITY COUNCIL ON ITEM 6Najera, Stephanie
From: Stack, Doug
Sent: Tuesday, September 18, 2012 3 :03 PM
To: Parker, Jeffrey C.
Subject: TRR Phase 1 Change Order
Hi Jeff,
In response to Council inquire regarding the change order amount /percentage for TRR Phase I, several
unanticipated subsurface conditions were encountered during construction impacting operations and
costs. Just to name a few:
• Discovery of numerous underground utility lines, valves, drainage pipes, buried headwall structures, etc. not
shown on historical maps and drawings which require removal and disposal.
• Discovery of buried burned debris near Legacy Road west of Tustin Ranch Road necessitating continued
avoidance of grading operations in the immediate area while procedures for handling were finalized.
• Discovery of petroleum -based stained soil within Legacy Road east of Tustin Ranch Road necessitating
continued avoidance of grading operations in the immediate area while procedures for handling were
finalized.
• Discovery of cement - treated soils covered by a layer of topsoil in the vicinity of two historical helicopter
pads necessitating crushing and pulverizing operations.
• Discovery of wet, saturated soils well above volumes originally anticipated from review of soil boring logs
and historical groundwater data.
Early on in construction, we realized that these discoveries could lead to a higher changer order condition. On
December 6, 2011, staff brought these issues to City Council's attention and Council authorized an additional
contingency of 15% in addition to the 10% statutory limit pursuant to Public Contract Code.
Staff worked closely with our construction manager and general contractor for full cost containment within
budgetary authority. What is important to again reinforce is that the City in assuming construction
responsibilities at the former MCAS Tustin is dealing with unknown and unusual conditions that cannot always
be accurately predicted. For projects that are substantially complex and prone to higher environmentally
challenging conditions, limits are often set higher to manage and mitigate the impact of such project related
risks.
Doug