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May 15, 2011
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liquefaction it was a major factor in 1989. >> liquefaction is a situation where you looking at soft soils. what happens is it's subjected to strong shaking it loses some of the cohesive strength and begins to act more like a liquid as opposed to a solid. what that means for construction purposes, in extreme cases this structures can fall over. the marina district in particular, most of the damage was related to liquefaction in the '89 earthquake. >> are there other problems in the bay area? >> pretty much anywhere along the bay front, is built on landfill. when you got reclaimed land you are building on soft soil. so the real risk in those areas. >> and in japan, horrible quake and tsunami there, what did we learn from that defect? >>inly certainly japanese earthe was a great tragedy with hundreds of thousands of lives lost but in some respects it was a greater success. it really showed that proper preparation for earthquakes can really save a lot of lives. most of the damage, most of deaths really came from the tsunami, but if you look at the buildings and infrastructure there wasn
liquefaction it was a major factor in 1989. >> liquefaction is a situation where you looking at soft soils. what happens is it's subjected to strong shaking it loses some of the cohesive strength and begins to act more like a liquid as opposed to a solid. what that means for construction purposes, in extreme cases this structures can fall over. the marina district in particular, most of the damage was related to liquefaction in the '89 earthquake. >> are there other problems in the...
SFGTV2: San Francisco Government Television
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48
May 2, 2011
05/11
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liquefaction, liquefaction is a term they use when the ground is loose. usually when structures or infrastructure is built on sand or land fill, something that's not solid, what happens is in shaking, during an earthquake, the earth that's very loose, that sand or land fill, acts like water. this is sand, sand and water coming up through a hole. in japan, all these buildings were built on liquefaction. i forget what year this was, but it was one of the bigger earthquakes. 7 story buildings built on liquefaction. the amount of time the earth shook, the earth became liquid and as it became liquid, the building sank into it until it stopped. when it stopped it just fell over. light damage buildings, superficial damage, broken windows, some plaster that might be cracked but basically a light damage building would be one that has mostly damage to the contents. shelves falling over, windows broken, that type of thing. if you had to go into a light damaged building, you would use these procedures. of course you gather information about a building before you go i
liquefaction, liquefaction is a term they use when the ground is loose. usually when structures or infrastructure is built on sand or land fill, something that's not solid, what happens is in shaking, during an earthquake, the earth that's very loose, that sand or land fill, acts like water. this is sand, sand and water coming up through a hole. in japan, all these buildings were built on liquefaction. i forget what year this was, but it was one of the bigger earthquakes. 7 story buildings...
SFGTV2: San Francisco Government Television
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49
May 29, 2011
05/11
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it is all sold and liquefaction. >> treasure island is unique. it was originally developed to be the location of the world fair with the understanding that once it was finished, that would become the location of san francisco international airport. it is 11,000 feet long. in those days, the thought that was more than enough to land any conceivable airplane. they thought it was ideal. they said that we have all kinds of sand out in the bay from the sacramento river. we will take the stand out of the bay and create this island. the sand is loose and below the water. it liquefied in 1957. it liquefied in 1989 during the loma prieta. it was similar to what happened in the marina. >> as they move along and developed treasure island, the developer also has to provide stabilization programs. >> the sand has to be strengthened so that it will not liquefy. the buildings have to gain support below the sand in more confident material. >> we were talking about the waterfront. here's the very building. here is the intersection of the water and the land. the a
it is all sold and liquefaction. >> treasure island is unique. it was originally developed to be the location of the world fair with the understanding that once it was finished, that would become the location of san francisco international airport. it is 11,000 feet long. in those days, the thought that was more than enough to land any conceivable airplane. they thought it was ideal. they said that we have all kinds of sand out in the bay from the sacramento river. we will take the stand...
SFGTV: San Francisco Government Television
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May 6, 2011
05/11
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>> liquefaction -- the crown settles, but it is not a catastrophic -- the ground settles, but it is not a cass strophic event. you might give boiling of water. >> and dynamic compaction. i assume there is an environmental impact report. what would happen to the bay creatures? i would imagine if he made a loud noise -- he made it sound like it was an earthquake simulation. >> it is really no worse than a pile driving operation. it is not a loud noise at all. so, once we go through those two concepts -- [laughter] once we go through those two procedures, of be anticipate losing two to 3 feet of elevation. we will have to bring soil in to bring that up to development grade. i will go into that in a moment. just over 1 million cubic yards will be imported. >> foreign alta to -- for an altitude increase of how much? >> i will get into that. we anticipate that buildings from six stories to 10 stories can be built on conventional foundations. they will not to have -- they will not have to have a pile driving. the taller ones will have to have piled foundations. >> i want to point out -- in the
>> liquefaction -- the crown settles, but it is not a catastrophic -- the ground settles, but it is not a cass strophic event. you might give boiling of water. >> and dynamic compaction. i assume there is an environmental impact report. what would happen to the bay creatures? i would imagine if he made a loud noise -- he made it sound like it was an earthquake simulation. >> it is really no worse than a pile driving operation. it is not a loud noise at all. so, once we go...
SFGTV2: San Francisco Government Television
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164
May 24, 2011
05/11
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was made to replace a number of pipeline segments on the peninsula where we are vulnerable to liquefaction. this is in the -- in to the additional scope in three different occasions. i will elaborate more on the cost increases. more from that perspective later in my presentation. >> it does occur to me that a couple of the projects we have been tracking in terms of costs have had some cost increases. if you could just give me an update on that spread sheet you give me from time to time. >> in the reporting quarter, we have some projects that we were forecasted to complete almost six months later. i wanted to elaborate more on the regional projects, which are the four above the darker line. this is a project that is now completed. it has reached the central completion. we need to keep the contract opened to allow the contractor to come back and perform some of the repairs at no cost to us. they accidently damage being closure of the generator on site. what is important to know is that the facility is fully operational. we just need to extend the contract for the repair. for the peninsula pi
was made to replace a number of pipeline segments on the peninsula where we are vulnerable to liquefaction. this is in the -- in to the additional scope in three different occasions. i will elaborate more on the cost increases. more from that perspective later in my presentation. >> it does occur to me that a couple of the projects we have been tracking in terms of costs have had some cost increases. if you could just give me an update on that spread sheet you give me from time to time....
SFGTV2: San Francisco Government Television
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May 5, 2011
05/11
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there was a lot of water damage we might have even had some liquefaction soil failure. we had a major failure. >> that's right. this tribute goes all the way to golden gate. this is in a mountain lake and beyond ththat, it was a surface flow. this is a reservoir. on my right is this defensive the positive dune sand. the wind blows, it comes from the ocean beach. because the sand is moving, you can see evidence along this side of the hill in 1989. the vibrations in accelerated. you have a significant amount of movement to the point that the homes that uc had very severe damage for two blocks. we recognized what the problem was at the time, it was a matter of loose sand on a very steep slope. thank you for the effort. we were able to get federal funding and design which you see in the upper walls. the lower walls was actually billed as part of the wpa. the upper wall was built in 1991-'92. this is a concrete wall and it has rocked going through the wall that extends the distance of 80 feet beyond the wall. the next earthquake occurs, the wall is designed to resist and the
there was a lot of water damage we might have even had some liquefaction soil failure. we had a major failure. >> that's right. this tribute goes all the way to golden gate. this is in a mountain lake and beyond ththat, it was a surface flow. this is a reservoir. on my right is this defensive the positive dune sand. the wind blows, it comes from the ocean beach. because the sand is moving, you can see evidence along this side of the hill in 1989. the vibrations in accelerated. you have a...
SFGTV2: San Francisco Government Television
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60
May 8, 2011
05/11
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it not only has liquefaction, but it also has a hillside stability issues. while it may be stable sporadically, when the earthquake comes, the slopes may fail. as a minimum, they should retain the services of a geotechnical and structural engineer, and there are well qualified people who come out. i am not just talking about and inspection service, i'm talking that licensed engineer, geotechnical, to look around, look at the maps available, and write an opinion letter as to the adequacy of the structure or the soil. there is another thing to consider when you are buying and building to the east of the van ness ave. a third map. this map depicts the area of the fire that followed the 1906 earthquake. the blue is where all the buildings were destroyed or badly damaged by the fire. as a result, the ashes from those fires remained on site. in those days, lead paint was used to paint the sides of buildings. it is a known carcinogen. it is a hazardous material. what they did was after the earthquake, they took these mounds of sand, the valencia st. hill, if you go
it not only has liquefaction, but it also has a hillside stability issues. while it may be stable sporadically, when the earthquake comes, the slopes may fail. as a minimum, they should retain the services of a geotechnical and structural engineer, and there are well qualified people who come out. i am not just talking about and inspection service, i'm talking that licensed engineer, geotechnical, to look around, look at the maps available, and write an opinion letter as to the adequacy of the...
SFGTV: San Francisco Government Television
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May 8, 2011
05/11
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that event in new zealand, liquefaction is something that we talk about, but until you see pictures oft right after it happened, i would encourage people to look at pictures of new zealand, christchurch after the event. they brought back pictures of a car. this really brought it home. we talk about this all the time and it is absolutely, positively the truth. neighbors are the ones that rescue neighbors. that is what happened in japan, that is what will happen here, are partners with the red cross and every other agency, we have to keep the focus on community resiliency. does anybody have any comments on christchurch new zealand? the japan van, very early, there will be a lot of lessons to be learned. we don't have the experts to really dissect it yet, i wanted to hone in on the experience in washington, the ringside seats in trying to get a public message out about this event. we were there 48 hours after the earthquake and a tsunami. mr. the really deal with the radiation aftermath. watching our partners in the federal government having offline conversations with them, they got hung
that event in new zealand, liquefaction is something that we talk about, but until you see pictures oft right after it happened, i would encourage people to look at pictures of new zealand, christchurch after the event. they brought back pictures of a car. this really brought it home. we talk about this all the time and it is absolutely, positively the truth. neighbors are the ones that rescue neighbors. that is what happened in japan, that is what will happen here, are partners with the red...
SFGTV2: San Francisco Government Television
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98
May 23, 2011
05/11
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>> this area, the ground water is deep, so you do not have to worry about the liquefaction. you have to worry about the loose sand during an earthquake. we estimate between 2 inches and 3 inches of settlement. these piles will hold the building up and the ground will settle around the piles and not cause damage to the structure. they will screw this into the ground by using a combination of forces. it will push and twisted into the ground. the upper 20, 30 feet goes easily, and then it starts to tighten. then at some point, it could actually stop the pile. the resistance could be so strong that it will sure off the pile and that is when we stop. >> your firm or somebody here is a special inspector, paying attention to how this is done? >> that is correct. we are observing what is done. >> we get reports saying, yes, it a mess -- and met the requirements for here were the problems in this is how they fixed it. what are they doing? >> they are screwing it into the ground. these are the marks. for every foot, the steel guy is recording the pressure on the steel. about how many
>> this area, the ground water is deep, so you do not have to worry about the liquefaction. you have to worry about the loose sand during an earthquake. we estimate between 2 inches and 3 inches of settlement. these piles will hold the building up and the ground will settle around the piles and not cause damage to the structure. they will screw this into the ground by using a combination of forces. it will push and twisted into the ground. the upper 20, 30 feet goes easily, and then it...