Sunday, December 27, 2009
Wednesday, December 23, 2009
revised ground landscape plan with grasses
Tuesday, December 22, 2009
Monday, December 14, 2009
sample detail
All,
Attached is a sample detail. We are preparing other details, using the same style and format. This detail shows the transition on the southern-most walkway. This detail illustrates three special cases:
1- Dual media planted profile (left)
2- Pavement including measure to collect and manage concentrated runoff flow against the wall
3- ‘planter’ with enhance drainage measures to handle concentrated flow
The conditions at the northern roof area will be subtly different.
Slope Stabilization notes
All,
I did a back-of the-envelope calculation for the geogrid slope stabilization system. Unfortunately, my conclusion is that we cannot support the 45 degree slope using this method. Given the geometry of the roof area, the maximum slope that can be supported, by my estimation, is 25 degrees, or 50% slope. Therefore, fixed anchors, of one sort or another will be necessary.
Refined calculations will result in lower estimates for the pull-out requirements for individual anchors. However, as a practical matter, it makes sense to choose one anchor design. Saving can be achieved by spacing the anchors more widely on mild slopes.
I think that it may be make sense to install the anchors so that the threaded pins project 8 inches. This will make attachment of the tendons for the cellular confinement web easier to do accomplish in the field.
Drainage Details and Design
See attached memo and annotated sections.
The drainage plan has 14 scuppers.
On a related topic, I think that it may be advantageous to have the anchor pins, protrude 8 inches up for from the slab.
Some more things to consider:
1- The minimum pavement profile on the south side of the project will be 5.5 inches. This will accommodate a ½” drain sheet, 3 inches of granular base drainage media, and 2 inches of decomposed concrete. Where needed a 2-inch high perforated drainage conduit can be accommodated in this profile thickness. This means that the minimum soil depth adjacent to the pavement in this area will be 5.5 inches and not 4 inches.
2- Note also, that the thickened and raised slab cuts across the path. The super-elevation of this linear feature above slab appears to be 11.5 inches. In order to carry the pavement over this, the pavement profile in these areas will have to be 13.5 inches. I assume that this assumption is already built into the path design.
3- Please confirm that the curb surrounding the southern walkway will be precast concrete. It will vary in height depending on the thickness of the adjacent pavement profile.
4- The curb at the northern walkway will be metal
5- A number of the area roof drains on the northern side conflicts with a walls or curbs. These should be moved so that they are squarely under the pavement or the planted areas. If in the walkway, I assume that you will want surface grates (correct?)
Thursday, December 10, 2009
Slope Stabilization
Wednesday, December 9, 2009
Meeting Minutes Dec 8th 2009
Meeting Minutes:
Participants: Mark, Martin, John, Eric, Aaron, Carina, Charlie, Lisa
Date: Dec 8th, 2009 2pm
Summary of Discussion:
Review of cover system components:
We have two distinct environments on the flat areas. There are two shallow areas which would have membrane, root barrier, dense fabric, irrigation on a 4' spacing within a 2" layer of a light weight granular and then a filter fabric and then a growth media of various depths. There are other areas that are uniformly 12" thick. In these areas we would put a drain panel, granular media and separation filter fabric, growth media and irrigation installed much closer such as 18" apart. this irrigation would rest closer to the top of the growing media.
We also have the steep areas
the first approach is a low permeability sheet train by epro with growth media and irrigation close the surface. On the steeper areas would require a soil confinement web which would be 8" thick and would tether to the anchors or upper geo grid on the surface this would be true for the 1:1 slope case. These steep slopes would also require a coco fiber mat to hold the soil in place until the plants become established
The areas that are decomposed granite paths would be placed over a sheet drain and a granular material and separation filter fabric so the water can flow underneath the paths.
For slopes stabilization and sheer forces we are measuring the average thickness of the growth media. if it is a 12' layer the vertical pressure on that slope is approximately 80 lb. on the slope. So we could in reality only have a depth 8.5 inches to meet the engineered requirements.
we are assuming 45 or 30 degrees as this is close to two existing cases. If we determine to put in anchors we may as well design for the maximum weight.
We are also assuming that we will use to media types throughout the roofsystem.
charlie explained that most roof failure is a result of fabric/ fabric slide. Mark described as mini tectonic shift.
Budget, CD'S:
Mark would like a clear picture of cost before he makes any decisions. Charlie is confident that the budget we produce at the end of december will be accurate and sufficient for mark to make decisions.
Design Build Clarification:
Roofscapes acts as a specifier and more of an enforcing agency to ensure that the roof is installed as it was designed. please see email sent 12.09.09 with more detail
Slope stabilization :
we are currently looking at two systems an anchor system and a geo grid system. There is quick calculation charlie can do that will determine friction of the soil and will calculate the resistance of the force and determine the overbalance on the downward force of the slope with the geo grid esteems as it should keep everything in place. there needs ti be a bit more thought in this area. We will evaluate cost and security of each option and will keep mark abreast of any decisions.
Martin provided clarification on parapet walls and we will work on the detailing over the next few weeks. The entire deck will be waterproofed and then the walls will be poured with an extra layer up against the walls. The root barrier will not work to go underneath the parapet walls. The scuppers were discussed and everyone seemed in agreement that fewer larger ones are better an that they need to be sealed as well.
The question of the 30 mil root barrier came up again. Charlie and Lisa recommend the 30 mil and the Roofscapes warranty will not be able to include any part of the waterproofing if it is not 30 mil. The 30 mil is easier to hot weld than the 15 mil. Mark would like to review the total budget that will be provided on Dec 21st before he decides on which to choose.
Park areas:
We are responsible to restore the park areas to the state they were before. The lower landscape areas need to be coordinated as they are on same water system as the building and roof.
The areas to restore are the area by the trailer, the pavilion and these need to be returned to sod. The internal areas can be seeded or sod.
Action Items:
1.Charlie will coordinate with Belzberg to get details and decisions made on the drainage design and anchoring system
2. Evo and Charlie will coordinate with Martin on schedule and providing what he needs to move forward
3. Lisa and Karla will also provide CD's by Dec 21st of the on ground landscape so that it can be bid at same time.
4. Martin will provide schedule of items that need to be addressed by when
Tuesday, December 8, 2009
Meeting Agenda Dec 8th, 2009
Agenda:1. cover system requirements and detail2.design build vs. competitive bid possible partnership Roofscapes/ Valley Crest..other contacts?3. schedule, city requirements, expectations, construction check points4. warranties5.possibilities and constraints: Time, Budget, Quality
Questions and clarifications
Charlie's sleeving idea
If there is any question about how the slope will be supported, perhaps it would make sense to keep options open. When the medial walls are ‘shot,’ it would be a good idea to install 2” PVC sleeves through the walls every 2 feet. This way the a geogrid solution could always be introduced if the anchors end up being impractical or too costly.
Also, sleeves will be needed for electrical conduit and water supply piping.
The sleeves would not constitute ‘weep holes’ since we still have to be concerned about root-protection. See attached sketch.
Any further thoughts after receiving my preliminary flow pattern map for the green roof?
Friday, December 4, 2009
charlie's drainage comments
I am zeroing in on the drainage issue. See my attached diagram. This is how I currently understand drainage patterns after our recent discussions. Heavy red arrows represent concentrated flows. Lighter arrows distributed or sheet-like flow.
1- If in fact point B is at a higher elevation than point A, then we will need another scupper at point B. Please let me know what the slab elevations are at points A and B.
2- Scupper 5 and 6 will be points of flow concentration.
3- Significant concentration of flow is inevitable on both the north and south sides of wall ‘W’
4- Flow will concentrate along most medial walls.
5- Since there is only one drain north of the ramp, we will need another scupper at location 7.
6- After our conversation, I was no longer confident about the flow pattern near scupper 4. Will flow be toward the NW or SE along the beam (need to elevations along this obstruction)?
7- I think it makes more sense to manage water through one (or two) scuppers along wall ‘X;’ i.e., at A and/or B. The reason is that for water to follow the slope of the slab, it will have to flow through a number of additional scuppers and them be dispersed in a sheet drain under the decomposed granite pathway. I am concerned that this drainage path will be inefficient.
Please provide more information about what is happening where your plan shows a boundary between orange and blue. What is preventing flow from draining across this line? My understanding is that there are no drains along this axis.
I got the impression during our conversation today that you have been assuming that the medial walls will havemany scuppers; i.e., sufficient to prevent these walls from acting like barriers to flow. Do you have elevations of the walls, showing these openings? I am very concerned that root protection will compromised at scuppers. It will be challenging to hot-air weld the root-barrier so that it can protect the waterproofing in the opening. This is one reason that I have been assuming that the number of scuppers would be few, large, and strategically located.
Even if your plans are to have many scuppers through the medial walls, I still think it is important to have the ‘master’ scuppers in the locations that I have shown. These should all have vertical shafts that allow them to be inspected and serviced.
It would be great if you could provide a CAD file with spot elevations for the slab shown.
Since we are on a short fuse- please send current CAD plans and sections. We will use these as a basis for preparing details.
I will be available to discuss this some more on Sunday. Call my cell phone.
charlie's comments
Dear Carina and Lisa,
As I understand it the deck is being poured today. Therefore, any support system must either be designed without anchors or anchors must be drilled into the finished deck.
At the moment, I have the following pressing questions and comments:
1- The revised anchoring plan offered by the structural engineer is not, in any way, similar to our proposal. We have no objections to it, if this what the structural wants to propose. However, it is important to keep in mind that some of these anchors will ALSO have to be placed in the walls that will poured in the middle of the steep slope. This solution will require the ADDITION of a way to seal the root-barrier where the bar will penetrate through it on the downhill side of the wall. Off hand, I don’t have solution for this.
2- I will be happy to layout the anchors. The easiest thing will be to assume that there will be one anchor for every 8 sf. There will be about 300 anchors. The ONLY CAD drawing we have is A2.1.a last modified on 10-22-09. However, this drawings seems to be missing critical layers. Can you please send an Etransmit file for this, or a more recent drawing?.
3- Note that downslope from the raised beam, the anchors should be drilled into the beam. This beam should support the loads, and no additional anchors should be required downslope of the beam.
4- We are not designing the anchors. However, the final design must include a flange with a washer that will allow us to seal the root-barrier. The design could be as simple as a threaded bolt made from stainless steel or brass. The installation process would be to: 1) place a S.S. or brass washer 3” in diameter over the bolt, 2) force root-barrier membrane over the bolt, 3) a matching washer would be placed over the membrane, and 4) a S.S. or brass bold would be tightened over the upper washer. This concept design is simple to install and build. However, either the structural engineer of another engineer specializing in concrete must determine the diameter of the bold, its depth of embedment, method for securing the bolts into the concrete, and material (S.S. or brass). With this information Roofscapes, Inc. could research manufactures that offer bolts/washers that would satisfy the structural engineers requirements.
5- I have received no feedback on the drainage plan. In particular:
a. Will there be a line of roof drains following the northern wall of the ramp? Since the slab is being poured now, is the plan to go back afterward and bore holes for the drains. Are drains being cast into the slab now? If there are no drains along this alignment, this will definitely affect plans for drainage of the green roof.
b. I am confused about the pattern of flow in the small isolated triangular area south of the ramp (see area circled in pink on the attached scan). I would like to confirm that water will flow along the wall toward a scupper located at #5.
c. Do you have comments about the proposed locations of the scuppers
d. Will a large grate be added at the extreme southwest in order to receive flow concentrated flow in this area?
e. Are scuppers 4”x24” OK with everyone?
f. Once we know for sure where the grates, drains and scuppers are, we can layout the internal conduit that will collect concentrated flow and convey it to the outlets
g. Can you provide information on the design storm that is being used to size drainage facilities elsewhere on the site?
6- Where are the stub-ups for the irrigation supply? As mentioned in the past, these can be anywhere. We can run the piping below grade to where we need it. It is very important to include sleeves through the walls and curbs for the supply lines. These must be located before the walls are installed. Who is preparing this detail? Don’t forget electrical conduit.
7- With CD-time approaching, we should agree on a the details that will be generated by Roofscapes. We will need an up-to-date plan (see above) and all the sections. We can prepare dstials and specifications by 12-18. Details that we foresee as being necessary. Are:
a. Scupper (typ), including access shaft and distribution box
b. Perforated conduit layout
c. Perforated conduit detail
d. Slope stabilization assembly
e. Assembly profile for shallow soil areas, including typ. detail for capillary irrigation system.
f. Assembly profile for deep soil areas
g. Area drain detail, showing access chamber
h. Transition to decomposed granite walkway
i. Transition to wall
j. Detail at slope anchor
8- Irrigation design is not in our scope, but we can provide basic information in the specification that will guide the installation. We can also provide you with some ‘boiler-plate’ details for valve chambers that you can add to the CD set. You can ask for the irrigation layout, based on Netafim, to be prepared by the contractor and submitted for approval by Belsberg.
9- We will provide specifications for the various green roof profiles. It would make sense to include the decomposed concrete pathways in the green roof specification, since drainage underneath the paths is integrally related to the adjacent green roof areas.
Thursday, December 3, 2009
MST Strap
Carina,
I’ve attached some data you can forward to the engineer that the landscape architect is going to use to design the soil retention system.
This is a metal strap that can be fed beneath the planter wall at Grid ‘D’ and allow us to bolt to the flat portion of roof while still leaving about 36” of strap at the downhill side. This should prevent loads from transferring to the wall because it’s not using the soil on the flat to hold the geo-grid.
- just an idea you can maybe work from; William Koh seemed receptive to the concept (I already spoke with him about it)… but you do still need to provide him with engineering for the entire package so he can review it against the loads his roof is designed for.
Eric Steppner
Wednesday, December 2, 2009
anchor issue
charlie's estimate, based on a FS of 1.25 is as follows
45 degree slope
Horizontal spacing
2 4
Vertical
Spacing 2 250 lb 504 lb 10 rows
4 504 lb 1,008 lb 5 rows
6 756 lb 3 rows
33 degree slope
Horizontal spacing
2 4
Vertical
Spacing 2 179 lb 360 lb 10 rows
4 360 lb 720 lb 5 rows
6 540 lb 3 rows