that is their design, and they know how heavy the structure is, and they know their structural elements. so you know, from a geotechnical engineer's perspective, we take whatever the structural engineer's estimate as far as the weight and pressures on the foundations are concerned can he -- >> supervisor peskin: understood. and then in your response to ray louie's letter of february 2, 2009, that's the letter where mr. louie who first came before this committee and didn't remember, but they be at his second remembered a lot more than he did at his first interview. on february 18 -- and i'm trying to find the letter here in my stack -- treadwell and rollo, with your signature on it, responded, and response number five -- and this is with regard to the reasons for the larger than expected

settlements, you indicate that it could be attributed to several possible factors, one of which you just talked about, which was the languager than anticipated dewatering on-site. [please stand by for captioner switch]

do you think dewatering at 350 or transbay could have had an impact on the settlement. >> i believe the mission was a cut off wall and we had measured, the water levels had already been drawn down quite a bit outside of 350 mission's

footprint, if you will. but the issue with the watering is really extent in duration. t.j.p.a., as you know, is approximately 1500 feet long about 180 feet wide and about 60 feet deep. imagine a bathtub you have to empty so you can work dry when you are constructing it. and that project was a much longer project, it's been going on, for i don't know how many years but it's been going on for a long time. the impact of that massive dewatering is very large outside in terms of a footprint it can impact the water outside, we have seen in the data from the t.j.p.a. own consultant, they dropped it

outside t.j.p.a.'s own excavation by something like 20 feet which is very significant. that's one element. the second one, also the salesforce tower project, which is a very large footprint project that went on for a number of years and had dewatering associated with that project as well. so between the t.j.p.a. project and the salesforce project with really on long duration and dewatering and pretty massive amount of footprint to dewater, those two have had, in my opinion, quite a bit of impact in terms of sediment in the tower. >> but absent that, the millennium sunk twice as much

as predicted, neither one of the other projects just referenced had even turned their first shovel-full of dirt. >> true. see the thing is, when you dewater something, the water will take time to come back to its natural level. millennium tower desettling stopped sometime in 2008, it impacted the tower. so by the time they turned off the dewatering and let the water kind of come up, as you can imagine, water, when it comes up, it lightens the load so that's the beneficial effect of water getting back to static level.

another 2-4 inches was remaining and based on the data, i'm convinced we were reaching the lower bound of that additional settlement before activities with t.j.p.a. started that kind of started the acceleration, the second acceleration of the settlement. >> is it true where ground water levels are at lower elevations on one side of the building than the other, the side with the lowest ground water level would be where differential settlement would be the greatest? >> you mean, i'm not following you. >> supervisor peskin: are ground water levels uniform or can they be higher or lower? >> if you let it come up, it will come to its natural level everywhere. if you have deexcavation, you

have a hydrostatic up lift you are trying to withstand with the basement lower, but the water -- you have the same amount of water head, if you will. the natural water is here. the basement you are looking at is somewhere deeper, but if you let everything stabilize, it will, the head of the water will come up to its natural level. >> supervisor peskin: and does it do that uniformly? in other words, why is there differential settlement at the millennium tower tilting northwest, are there different water gradients, sub-surface? >> it's variable from the core to the edges and that's why, for example, in our original estimate we had 4-6 inches. so there was about 2 inches of difference in settlement of the tower, if you will, the pile cap they have, that's because

of the weight of the building is not uniform everywhere. it's usually heavier in the core than the edges. so that's why, we had estimated two inches of differential settlement. that's something they took to design the map in holding in that differential. but that is structural, desimone is the one to answer that question. >> supervisor peskin: in 2009 it was your opinion the building was at that time settling uniformly and not differentially. >> we had only one settlement point which is at the core. i didn't have any knowledge to say one side is more than the other at the time. >> supervisor peskin: interesting.

let me just find this. let me talk about your response. the question from mr. louis, are there any differential settlements within the high rise building and your response was one line, we are not aware of any differential settlement issues within the high rise tower but you didn't go onto say because we only looked at it at one point, if you only look at one point you wouldn't be aware of differential settlement. >> but that is response four, supervisor. there's only one point being monitored. >> supervisor peskin: are the actual total and differential settlements being monitored now. you say currently the benchmark on the wall is being monitored, so the answer is really no. only one point is being monitored. we should probably hear from mr. tom from d.b.i., or somebody else from d.b.i. as to how they looked at that, but certainly as a lay person, i

looked at that saying the building is not settling differentially. but the actual answer 10 years later, it may or may not have been, we only had one data point. >> that's correct. >> supervisor peskin: let me ask you this. would you agree the millennium tower should have been constructed with foundations that extended all the way to bedrock? in retrospect? >> i think, first of all, the bearing material that the foundation for the millennium tower is in, it supports many high rise buildings in the city. before millennium and after millennium as well. the settlements we estimated was acceptable by the design team and they designed a building accordingly. but if you go to rock, then you

would not have settlement. or you would have very little settlement. >> supervisor peskin: did treadwill and rono do the geotechnical work on transbay as well? >> no. >> supervisor peskin: that was all era? >> that was my understanding. >> supervisor peskin: did you have the benefit of that data later on by 2009? no, by 2009 you wouldn't have had the benefit of that data? >> no. >> supervisor peskin: and then, let me change gears for just a second because part of this entire exercise is to learn going forward for the city and county of san francisco, and i am in receipt of a letter with regard to a building that sits next to the ocean wide property downtown, actually very close to millennium, that would lead me to believe that there is

some differential settlement occurring at the federal, at the f.d.i.c. building at 25 jessie street. are you involved? is langan involved? >> langan is involved but i am not. >> supervisor peskin: so asking you questions about that would not be productive, would it? >> i wouldn't know. i was only involved on the earthquake ground motions. >> supervisor peskin: for ocean wide? >> correct. >> supervisor peskin: not as it would have impacted adjoining structures that may now be -- >> [off mic] may have been involved in that, yes. >> supervisor peskin: colleagues, do you have questions for mr. golsorki? i don't believe i have any

further questions but maybe we can get mr. straun or mr. tom to come up. i might have a couple more questions for you. and thank you for your candor. >> thank you very much. >> if i could, i just want to mention on the second page of the revised geotechnical investigation report, there appears to be a reference to the earlier reports that you asked about early on and in particular there's a reference to a report dated 14, august, 2000. dr. golisorki referenced 2001 one time but i believe -- that's the correct date. >> supervisor peskin: and dr. golsorki, do you remember with regard to the circa 2000 report was that for a concrete or steel building, do you remember? >> i know we looked at both concrete and steel, but honestly, i don't remember

right now. 18 years ago. >> supervisor peskin: i understand. do you have any idea when it went from steel to concrete? >> i don't. i mean, that was, we were not involved in that decision making. >> supervisor peskin: right. but the information that you got from desimone you analyzed were for pressures that would have come from heavier concrete? >> that's correct. >> supervisor peskin: all right. mr. tom, or mr. straun, if there was one tidbit of interesting development today it's in the two years we have been holding these hearings i have labored under the impression that the response to the department of building inspections, february 2nd, 2009, letter, wherein the department asks these now famous eight questions including whether or not the

building was tilting, differential settlement. and this goes back to a hearing we had a couple years ago but the funny story is we had a copy of the letter that d.b.i. wrote, which we got from d.b.i. but d.b.i. could not find and this has actually lead to changes in our record retention policies, the response that desimone gave d.b.i., including incorporated the treadwell and rolo letter authored by dr. golsorki, which interestingly enough were produced by millennium. our first hearing, i was like this is kind of interesting. we asked these questions, we never got any responses weish shooed a final certificate of occupancy, indeed we had gotten a response but i labored the last couple years under the impression the way at least a lay person would read this is no, the building was not tilting.

but now if i have learned one thing, it's actually there was one data point and you can't tell anything from that data point. mr. tom, do you want to respond to that? >> good morning, supervisors, ron tom, building inspector at the department of inspection. the department prior to changes and implementation what we categorize s 18 for tall buildings did not keep or maintain records for settlement. in fact, settlement, if it manifest itself in neighboring properties or within the property itself could be brought to our attention and we would administer the process to do an investigation and require certain parties, professionals, the designers to provide is a report for us to assess. other than that, we have no ability to go monitor

buildings, not even today. now having said that, as you know for the record, during the period of time during this investigation was going on, or actually the question, the letter that was questioning the conditions of the property was under a different administration, preceded the current executive team and we tried to learn as much as we could by investigating our own records. having said that, because of the benefit of the hearings and also because you have continued to look into this issue for the benefit of the city and process of approving tall buildings, we have implemented a whole lot of changes that will now actually address any settlement because we are now through the current administrative bulletin number s, information sheet s-18

require a 10-year monitoring period for all tall buildings. and tall buildings by definition are 240 feet or greater. there are a host of other requirements that will provide us additional records, should there be an occurrence of any nature similar to what we are currently investigating. but this duration of 10 years is an annual report submitted to department of building inspection by the design team so there's a responsibility that carries forward even after sales of the property to say if it's a condo to the condo owner. that's a measure we think will address and provide us any information if it's connected to settlement. so settlement would not be just a single point any more. it will be a host of points,

data points that are established when the c.f.c. is issued and monitored annually to see if it's settled at any of these points within the building perimeter and possibly also at the interior. >> supervisor peskin: i appreciate all those process improvements we are all learning from this unfortunate moment, but i guess my fundamental question to you is, would you, as a professional have read the letter of february 18th, 2009, the way i, as i lay person read it, which the building is not tilting. i'm not pointing a finger at mr. golsorki, but when i see a question that says are there any differential settlements within the high rise building then the response is we are not aware of any differential settlement issues within the high rise tower, and then the

next question are actual total and difference settlements being monitored now, and the answer is the benchmark on the core wall is being monitored, i don't see that as a response from a third party who works for the project sponsor as, we don't know. yet our recommendation is you take other data points. so whether i walk away from reading this letter is nothing to see here, yes it has sunk 8.3 inches, we don't anticipate settlement for the podium mid rise structure. we anticipate maybe an additional 2-4 inches of settlement. the way i would have read this, as a lay person is, yeah it was supposed to sink 4-6 inches, it sunk 8.3, it will sink another couple, don't worry about it, no, it's not tilting. that's the way i read the

letter. it doesn't say warning, department of building inspection, you should ask more questions, you should not answer the c.f.c. you should get us to find another data points. seems to me, that's the kind of question, that if not answered this way, you might have asked in return. >> not wanting to sound uncooperative, if i'm going to answer that, that's a whole lot of speculation on my part. putting myself in the shoes of deputy director at the time for permitting ray louis. i think that would be more appropriate to direct that question to mr. louis who still is in the employ of city and county. on a higher level, however, in

order -- there's settlement and differential settlement. and the two have a relationship but they also can be looked at independently as well. so as we have learned from experience, we have both occurring in 301 based on the department, our department has received, from the consultants. >> supervisor peskin: thank you. while we have you up here, do you want to give us any update on what's happening with our tall building working group and whether or not policies around de-watering are being analyzed? >> i was prepared today to provide an update. if you would like, i have some handouts i can provide for the supervisors. >> supervisor peskin: thank you, mr. tom.

>> on a higher level, i would direct the supervisors to page 4, slide 4, please. excuse me one second, i will grab some for the overhead. >> supervisor peskin: while you are doing that, because you are getting to the issue of peer review, mr. golesorkhi one thing we have long concluded in this committee and our investigations is that -- and this was a decision, however it happened, that your work was not independently peer reviewed. is that common? was it common at the time? is it common now?

can you share thoughts about that? >> sure. it was not required, or common at the time. but for the past few years after a313 was issued by d.b.i., and we haven't been involved in many of the tall new buildings, myself, personally. peer review is an excellent process. and it works. and it's great that it exists right now. or it has existed for the past few years. >> supervisor peskin: and do you know if there was any push back at the time. because obviously there was peer review on the structural, which is why we had professor mohele come before the committee. we heard a little from hanson tom why there wasn't peer

review on the >> yo technical aspects of the project. >> to my knowledge, it wasn't even discussed or considered. >> supervisor peskin: thank you. mr. tom? >> here is an update where we are today. 2016, as i eluded to earlier, we have s-18 issued and titled interim guidelines and procedures for structural geotechnical and seismic hazard engineering design review for new tall buildings. and now all the peer review appointments are made by d.b.i. and engineering design reviewers are compensated by d.b.i. two geotechnical engineers are required for projects in the city's softest soils unless the foundation reaches bedrock.

let's look at the time line of what's progressed. we have the information sheet that now requires monitoring data reports for duration of 10 years submitted to d.b.i. annually. february 2019, completed and posted a prequalified list of experts to serve on future peer review panels. so we are now prepared to assemble a peer review panel. april 2018, we received a board of directors recommendations for ap082 and now we are going to prepare ready for b.i.c., building inspection commission approval.

we have other collaborations and partnerships. we have 301 mission seismic safety committee from the office of the city administrator, and also the apply technology council is conducting a tall building study. specific to the building. close monitoring, july 2017 expert engineering report, structural safety review of millennium tower of 301 mission street and also february 4th 2018 was a follow-up report to find the settlement tilt do not adversely affect the building's structural safety. that was a conclusion of those reports. >> supervisor peskin: at that time? >> yes. >> supervisor peskin: the one thing we have to really underscore is it didn't say and in a month, and or in a year, or five years.

mr. hamberger was clear, at that moment in time. >> yes, supervisor, that is correct. but we also asked for a more current assessment as well. so we can bring up-to-date where the building is now. in terms of the safety. d.b.i. inspectors conduct life safety inspections every six months and the next one is scheduled for about june or july next year. so it will be more than likely next month. and i'm missing a sheet so i will just put this here. what is happening now? we have three permits issued to conduct exploratory work to determine existing conditions and collect concrete core samples. they occur in location of the

shoring wall, the mat foundation, basement wall of the podium structure. this work has started on two of the permits and we have several inspections that have been conducted by our staff. so i think i would like to stop there because i think that presents at least a snapshot where we are, where we have been and where we are going with the information sheet s-18 especially with the two geotechnical experts required and also the monitoring. those are powerful tools we did not have before. and as i said earlier, i think this is a great outcome and by-product of the hearings you started. we should feel, certainly as a department, we, with the retention policy of records that has been implemented, our engineers and plan reviewers are much more cognizant of what their obligations are in the

whole process. and we check with them to make sure they are up-to-date with that. >> supervisor peskin: i really appreciate it. we aren't holding these hearings because they are fun but because we want to see changes going forward. actually to that end, and i don't know if you are in receipt of a copy of this, but i will hand it to you. i have a document actually dated march of this year from a structural engineer with regard to differential settlement at 25 jessie street which is the aforementioned 18 story, 1981-era building. that letter indicates there is differential settlement occurring there. apparently it was the subject of a complaint that was investigated that may have elicited this letter and it indicates there's differential settlement on the order of an 8th of an inch between building

columns which columns are "typically 24 feet apart". it is a 90-foot wide building at the base, if you do the math on that, 90 divided by 24 is about 3.75. so round it up to 4. if you take that 8th inch and you multiply that by 4, it sounds to me like the f.d.i.c. building is now differentially settling a half inch. but again, i'm a lay person. so i don't know what i'm talking about. but i want to make sure that d.b.i. learns the lessons of 301 mission street as it applies to 25 jessie street. i will share this letter with you. but would like to hear what your thoughts, observations and course of action is with regard to the differential settlement at 25 jessie street.

>> supervisor, i am not aware of the, i guess this is a complaint on 25 jessie street. >> supervisor peskin: apparently, as i understand it, and looking online you could see there was a complaint and you could see that it was closed. but at any rate -- >> [off mic] >> supervisor peskin: supervisor kim also understands there is settlement. again, this is modern steel, relatively light building. and as we are embarking on what is in essence, another millennium called oceanwide, i just want to make sure that d.b.i. is on it. >> supervisor, i would request you provide me a little time. i will report back to this body at a future date at your calling for any update. and also in between, we will

communicate with you and your staff and other supervisors present so that you can have an update, with more detail, once i get back to the office. >> supervisor peskin: i will provide you with a copy of that letter. colleagues, if there are no further questions, i really want to thank dr. golesorkhi for coming. i'm sorry about your depositions and i appreciate your candor with the committee. >> thank you. you're welcome. >> supervisor kim: thank you very much. >> supervisor peskin: i would like to continue this item to the call of the chair after public comment, if there is any. >> at the time we will open it up to public comment on this item. please step up. >> good morning, i'm phyllis

deets, i'm a lay person. i have a simple question. i wonder to what extent rising sea levels are considered in these discussions, either as decisive considerations or geotechnical conditions to support the foundations, thank you. >> thank you. >> supervisor peskin: i imagine the tall building work group is wrestling with those concepts going forward. is there any other public comment? >> seeing no other public comment, public comment is now closed on this item. supervisor peskin? >> supervisor peskin: thank you, again, madam chair. and thank you, again, to the individuals who came today. some day we will get a fix at 301 mission street and good luck to the parties in settling that. as i have said repeatedly, i'm actually, if everybody could stop fighting for a minute and

do the fix, what portion of it afterward, that's the right thing. because meanwhile you have 400 individuals and families who are kind of living under a cloud. as well as the entire downtown to the extent that building fails to perform. it's a serious problem. so with that, madam chair, thank you for your and president breed's indulgence and i would like to continue this item to the call of the chair. >> we have a motion to continue this item to the call of the chair. just a follow-up, i would like to hear a little more about 25 jessie as well, because i have heard about settling issues there, so as we continue to build in this neighborhood, i think it's incredibly important we look at all the tall buildings along with the millennium. we could take this motion and do it without opposition. thank you very much. >> supervisor peskin: thank you. >> supervisor kim: mr. clerk, can you please call the remaining items, 7, 8, and 9.

>> clerk: various ordinances and resolutions authorizing the settlement of lawsuits against the city and county of san francisco. >> supervisor kim: thank you so much. and before we take a motion to convene into closed session, are there any members of the public who would like to testify on item 7, 8, or 9, seeing none. public comment is now closed. we will now convene to closed session so we are asking members of the public to please exit the room. do we have a motion to convene? we have a motion, we could do that without opposition. we are now entering into closed session.

[closed session]

[closed session]

>> supervisor kim: all right we are back in open session. city attorney mr. givner if you could report back what happened in closed session. >> sure, the committee voted unanimously to forward item 7, 8 and 9 fo the full board with with positive recommendation. >> could we take a motion not to disclose. we have a motion not to disclose closed session discussion. we could also forward these three with full recommendation. mr. clerk, is there any further business? >> clerk: there is no further business. >> supervisor kim: thank you. meeting is adjourned.

meeting is adjourned. [adjourned]

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