Other Serious Structural Design Errors:
1. Failure to Investigate Possible Serious Seismic Response Issues: Welding on the 1953 Tank Steel Plate Joints During On-Site Tank Construction
Standard ASTM A7 steel plate manufactured before 1957 did not restrict the chemical properties that makes steel weld-able. Weld-able steel plate had to be a special order or the Site welders had to pre-heat the plate to a specified temperature range and hold the temperature while welding 20m or more in the air. This is highly unlikely given the erection procedure required to pre-heat on Site.
If the steel carbon content exceeded maximum limits or the plate wasn’t pre-heated correctly, these defective welds could fail under cyclical seismic loading, releasing all of the tank contents above the failure under pressure. Steel contact during cyclical loading could ignite the tank contents and the contents spilled and contained behind the berms.
Critical Omission: Kinder Morgan’s Structural Engineer failed to investigate whether the existing welds were defective in both EFR and IFR Tanks. The 1953 tanks have never been “tested” in even a moderate earthquake. (The last serious earthquake in Greater Vancouver occurred in 1946 at Cumberland on Vancouver Island and registered approx. Mw 6.0 at the Burnaby site. That was seven years before they started to store oil at the tank farm.)
2. Failure to Investigate Possible Deficiencies in the Original Site Preparation for the 1953 Tanks Under Seismic Loading
The original foundation on the sloping site for the 1953 tanks was a likely a cut and fill. Did the Contractor use excavated soil from the cut to backfill on the fill side or imported granular fill? How did the Contractor fill in the three existing creek beds? The original bearing stratum was designed for the total weight of the tank and contents and not the overturning forces generated by the sloshing during an earthquake. Did Kinder Morgan retain a Geotechnical Firm to examine the existing site and determine the maximum bearing capacities under earthquake loading? Where are the calculated maximum bearing pressures for the EFR and IFR tanks under earthquake loading?
If existing excavated material was used on the fill side of the foundation, is it susceptible to liquefaction during an earthquake. Is the 66-year-old drainage system still diverting the existing creek flow away from the tank foundation or is the site saturated for periods each year?
Critical Omission: A competent structural engineer would ensure a GeoTech assess the bearing capacity of the existing foundation under earthquake loading. Kinder Morgan’s Structural Engineer appears to have completely ignored the existing foundation support for the 1953 Tanks.
3. Failure to Investigate the Existing Floating Roofs – Was the Roof Reinforced to Prevent Sinking and the Original Metal Seals on the Perimeter Replaced with Non-Metallic Ones to Prevent Sparking Under Earthquake Load
The JSCE Report states Japan forced a mandatory upgrade of floating roof design criteria after the 2003 Tokachi-oki Earthquake to increase roof buoyancy to prevent full exposure of tank contents and mitigate full surface tank fires. This mandated upgrade apparently prevented EFR Tank fires during the 2011 Mw 9.0 Tohoku Earthquake despite severe sloshing damage. IFR Tank floating roofs were upgraded too. Did Kinder Morgan’s Structural Engineer investigate the buoyancy of the existing floating roofs – source of full surface tank fires?
The second upgrade would be to replace the perimeter metal plate seals on the 1953 floating roofs, on both EFR and IFR Tanks, to prevent metal to metal contact igniting contents during earthquake sloshing. Did Kinder Morgan’s Structural Engineer investigate this sparking source for tank fires?
Critical Omission: Kinder Morgan failed to mention floating roof upgrades in their list of “seismic Upgrade” measures for the existing tanks. Their Structural Engineer didn’t address these serious fire risks during earthquakes – lessons learned from previous serious petroleum fires.
Reference: EGBC Submission: See Section 6.1
1. Experimental Study of Floating Roof Integrity for Seismic Sloshing, Nishi, 2008 – 381750052 STORAGE TANK CONFERENCE
LINK: PDF copy available by email. See CONTACT Page to request a copy.
Gordon L Dunnet, PEng Retired, Structural Engineer