BY JOHN BRIZDLE – We are hearing from the city that the required rail AIS (Archeological Inventory Survey) is almost complete. However, here’s what the city is not telling us. The city does not know the exact location of each rail column, and the city does not know the size of the underground foundations required for each rail column from Aloha Stadium to Ala Moana Center. Therefore, the AIS could be in the wrong place and/or it could fail to inspect the total construction area required to build each rail column.
The city has preliminary drawings showing where the rail columns could be located (preliminary drawings do not include any information about construction details underground). The city recently hired a mainland engineering company (AECOM Technical Services Inc.) to provide the next step in the FTA process called Final Design. The Final Design process will provide complete engineering solutions for Segments Three and Four (Aloha Stadium to Ala Moana Center). When the Final Design process is complete in approximately twelve to eighteen months, the city will have complete construction drawings and bid documents.
When AECOM is finished, will their column placements be the same or different than the current preliminary drawings? If they make changes in the column placements, will the city ask for a supplemental AIS? At this time, the city does not have enough engineering information to finish the AIS in the next few months.
If we look at the problems to be solved in the Final Design engineering phase, it is easy to see how rail column placements could be moved during the process. The AECOM engineers must design the underground supports for each rail column. The engineers will first have to test the soil at each potential rail column location. Then they will have to find the underground utilities running near each potential construction site. Then they must engineer a solution that satisfies the design criteria for the project (ability to withstand specific loads, wind, earthquakes etc.) and also moves but does not interrupt the underground water, sewer, gas, electric, and utility lines that may be affected by the planned construction.
Since the span between the rail columns has some flexibility, it is easy to see how final column placements could be moved several feet in order to facilitate construction (easier and cheaper to move the column than re-route, without interrupting, multiple underground utilities or risk pile driving damage to nearby buildings).
The current AIS is using a trenching technique that is approximately 20 feet by 3 feet. This may be sufficient if the survey is done where the engineers are calling for a single drilled shaft like those out in Ewa. The city knows the soil in Kakaako is labeled “Fill or Lagoonal Deposits” by their engineers and therefore the large drilled shafts used in Ewa will probably not work in Kakaako. If the drilled shafts will not satisfy the design criteria, then the engineers could call for multiple shafts or driven piles topped off with an underground pile cap that will become the base for each rail column. These engineering solutions take up much more land and require an open pit to work in to build the underground support (piles or multiple shafts, and pile cap) for each column. These solutions could require a construction pit that is 25 -35 feet square for each column.
So, here’s the problem. The city is not doing an adequate AIS because they are not taking into consideration the possibility that the final placement for each rail column in downtown Honolulu may be different a year from now from the present locations found on their preliminary drawings. Additionally, the city is not taking into consideration the possibility that the underground construction area for each rail column may be 10 times larger in downtown Honolulu than the construction area required for each rail column out in Ewa.
To do a proper AIS, the project must have a specific construction footprint. The rail project will not have a specific construction footprint from Aloha Stadium to Ala Moana Center until AECOM is finished. In order to complete the AIS for all potential rail project construction locations, as required by the recent Supreme Court decision, the city must wait for their engineers to finish the Final Design engineering process.