1. Progress of road construction of Via Limon (Limon Metal Corral)

Transcription

1 Progress Report for Site visit to Panamaes for the period through Peter Schiess Main focus of site visit was 1. Progress of road construction of Via Limon (Limon Metal Corral 2. Progress of construction from Metal Corral to rio Adentro, including bridge issues 3. Progress of road construction on Pia s property and towards Escondido 4. Beach road relocation 5. Panamaes interior roads, including Panamaes bridge site 6. Sunset Beach 1. Progress of road construction of Via Limon (Limon Metal Corral) Drove road with Ilka on The basic road prism is completed with the exception of quebrada El guabo and Rio Caldera. Items left are some minor ditch/drainage improvements. They were pointed out to Ilka at the time Figure 1: Via Limon road: Along the fnece line ditch lines needs to be formed with adequate ditch out so the ditch water drains away from the road subgrade. Or, additional excess escavation material can be placed to lift the road surface, so it is above the surrounding pasture land. Figure 2: well-formed ditch line. Important to provide ditch-out at an appropriatte location to drain water away from the road into the surrounding pasture Page 1

2 In general I duscussed with Ilka, that on the Via Limon road width, on occasion could be less than the specified 1.5 lanes (4.8m meters road surface) so that no living fence has to be cut. The road in general has ample dimensions to allow for turn-outs and passing, using the shoulders. Quebr. El Guabo can be crossed with a low-water crossing and culverts to handle low flow. Rio Caldera is becoming a question mark. Discussions with Pia and others about rain sesaon flow indicate substantial water levels, and especiallythe extreme event from 2007 created big flow rates indicating that maybe a bridge should be considered. If we stay wit h a low-water crossing it propbably requires about 4 culverts of 1.5 meters, each about 40 m long in order to allow for a gentle slope on the fill over the culverts. The fill need be hardened (concrete rock). Figure 3: Rio Caldera, looking towards Limon Figure 4: Rio Caldera, looking upstream. Two channels converge just above the crossing. The channel bank center-left (overgrown) was underwater during the extreme event of 2007 based on accounts by Pia. One possibility may be to install a series of arch-culverts, or oversized round culverts with the lower part buried in the stream bed. F I will provide schematic drawings for Ilka for el Guabo crossing and Rio Caldera. The current topog survey (done at the time by HA) do not allow for an exact design. However, for El Guabo the data are adequate and Ilka s experience make it not necessary to invest in additional topog surveys and design information. Page 2

3 Figure 5: Area where road-side ditch line is joined by a small draw (quebrada). The location is just before Rio Caldera. Here a setting pond should be created into which the road side ditch enters into as well as the small depression from the pasture. It breaks the water velocity in the ditch line (road grade andn ditch line on this stretch are about 13%). Overflow can then enter back into the ditch line (to the right in the pcture) and drain into Rio Caldera. Figure 6: Margianl soil type, characterized by an ash-like consistency. The white soil (pure silt ML according to USCS )has absolutely no cohesion, so is extremely erodible. This soil cannot be used to create fill. It can be used to lift the road surface but should be capped by a reddish clay soil (see figure 5 Figure 7: reddish, clay soil which forms an impermeable surface. When capped (covered ) with tosca/gravel it will provide for an excellent base and running surface Figure 8: Curve enlargement by metal corral. The silty material seen above cannot be used for building up a fill. Good-quality excavation material shall only be used for creating the fill. If need be, the curve radius can be somewhat reduced. It will also reduce fill slope length and fill slope height. The istuation was discussed with Ilka on location. Page 3

4 2. Progress of construction from Metal Corral to Rio Adentro, including bridge issues This stretch of road (about 800 meters is the most critical part of the whole road, both in terms of construction difficulties (Large excavation amounts and cuts in order to keep the grades to a manageable 13%) and its control over access to Panamaes during construction. Ilka and I reviewd work load and time left, until the rain season starts, by which the following has to be achieved: a. At the time of the site visit ( ) we established that approximately work days are left (assuming that rain season starts mid May). By that time: b. the road from Limon to Escondido has to be finished and capped with tosca c. the road through Max s property needs to be built and finished d. Bridge abutments have to be built by then in order for the bridge installation process to begin e. To achieve the time lines Ilka agreed to bring in a larger excavator (CAT 320 excavator) and additional dump trucks to speed up the construction process. A total of about 10,000 cubic meter need be excavated with a goal of moving 600 cubic meters or more per day (about 40 truck loads/day). The smaller excavator will be assigned to install the large diameter culverts at the end of Pia s property and begin on the work towards Escondido. f. The bridge has to be installed and in place before substantial rains are starting. For that to happen and to stay within a 20-day installation period, abutments have to be in place by about April 25 th and bridge elements delivered to the site in order for the bride to be completed by about mid May as the target date. g. During the abutment construction process and bridge installation access over the Via Limon to Panamaes is closed. Page 4

5 h. For the above reasons it is imperative that we get a hard timeline from the bridge supplier. It has to be understood by everyone involved that road access across Rio Adentro will be closed during the abutment construction as well as during the bridge installation process. The bridge installation process, according to the offered contract requires about 20 days. So it appears that access to Panamaes over Via Limon may be closed for about a 30-day period under the best of circumstances. i. In my view, alternate plans should be readied in case the installation process and therefore, access via Rio Adentro will not be available for a longer period of time. In this context I want to raise the question of our recourse available to us in case of under - or worse yet, non-performance by the bridge contractor. Figure 9: White soil (possibly ash from some geologic volcanic eruptions, silt, excavated from a road cut down, towards Rio Adentro. This material shall not be used to create a fill in the curve by the Metal Corral. Such excess excavation material can be used to lift road surfaces where road grades are gentle and not steep. But should be capped with a reddish clay soil to create an impermeable surface, prior to. tosca application Figure 10: Looking back towards Metal Corral from future bridge abutment. Abutment elevation is 2.7 meter above current road surface. That will insure appropriate clearance to allow for any extreme stream flow event to pass underneath the bridge. There is no space, however to allow for simultaneous traffic AND bridge installation during the bridge construction phase. During that time access will be closed except for 4- wheel drive SUV s and pickups. Page 5

6 Figure 11: Begin of excavation towards Rio Adentro. About 10,000 cubic meter of excavation will be moved, most of it up towards Metal Corral and then placed on the road towards Limon to raise the road surface there. Excess excavation cannot be dumped in the immediate vicinity because of the steep hill sides. Ilka is bringing in a larger excavator (CAT 320) and two more 15 m3 dump truck to speed up the construction pace. The road surface where the excavator is working will be cut down by about 3 meters to maintain a 13% road grade towards the bridge. 3. Progress of road construction on Pia s property and towards Escondido Progress on Pia s property advances verywell. By now the subgrade should be finished to where it enters the public access road by Erasmus finca. With the availability of the smaller excavator (CAT 312), work can be started on the quebrada crossing at the end of Pia s property Figure 12: Progress on road construction on Pia s. condition on Figure 13: same road segment as above by Ditch line and subgrade finished, ready for tosca application When reviewing the preliminary road location Ilka put in to allow for traffic to proceed to Panamaes we decided that this should be made the permanent location (see figure below). In the process it simplifies the quebrada crossing and maintaining public access on that stretch. Ground conditions Page 6

7 are so easy that there is no need for a design. Equipment operator and Ilka can finalize the road as per general specifications. Figure 14: new road location on Pia s property. Road ends near Erasmus finca. Overall construction may be simplified allowing for better accommodation of quebrada crossing and maintaining public right of way As part of the relocation of the road at the end of Pia s property, the public road from Erasmus property to stake #43 was surveyed and a quick design accomplished. In order to reduce the grade down to the quebrada as short stretch will be excavated by about 3 4 meters. Total volumes are comparable to the original location approaching the quebrada. Point locations and cut depths were reviewed with Ilka on location. Figure 15: New road location on public access from Erasmus finca (to the right) to quebrada crossing (to left). Final road grade will be about 3 meters lower where the red truck is right now in order to reduce the current grade of 22% to 13% Figure 16: looking South from quebrada (stake 42) towards Erasmus finca. Final raoad surface at top will be about 3.5 meters lower to maintain a 13% grade. Fence line on left will not be disdurbed. Cut bank will extend to the appropriate elevation and the subgrade leveled out towards the right. Page 7

8 Figure 17: Looking South towards quebrada crossing and Erasmus finca from stake 43. Quebrada crossing will have a 3.7 meter fill with a 1.5m x 30 meter long culvert. Figure 18: Looking towards Escondido. Originally a culvert has been considered for this location. WE can apply a lowwater crossing here. Simply use good, permeable rock material, so water from the left can percolate through. We can observe it during the first rain season. If it is not adequate or does not perform as anticipated we can always install a culvert later Page 8

9 4. Beach road relocation The new beach road location was alked and marked in the filed. A set of design drawings were submitted to Ovidin for use with public authorities to accomplish a land exchange. Important note. The road was located towards the bottom of the hill slope to reduce noise and sight emissions from local traffic. However, house can not be accessed from this public road except at its beginning (from station to about 70.0). Design drawings were ed to Ovidin. Figure 19: Example of beach road location at bottom of hill. Access to house site on the plateau on top (to the right in the picture will have to be from where the new beach road takes off from the existing public road, since it is too far down the hill for such purposes Page 9

10 5. Panamaes interior roads, including Panamaes bridge site Interior roads were reviewed on site with Andrew Coates and Edwina on Reviewed were questions of road link between entrance/gate house (entering from Max s property and begin of existing road design (stake # 58 on Cad drawings) as well as Panamaes crossing a. Ground conditions are straight forward, so that Ivan can stake out the alignment and the road can be built without the need of further design or surveys between the entrance and stake #58. Existing road standard dimensions that apply to the existing design can be carried through on this section. b. Panamaes crossing: The need for a second,, shorter bridge where an old culvert is located, was discussed. Also the issue of a fill within the flood plain in order to raise the road surface above high water marks. One of the problem will be that the road fill will act like a dam during extreme events. To reduce the pressure on the road fill in such an event I prose to swing the road alignment upstream so high-water will be diverted to the two bridge locations with their channels. Figure 20: Internal main lobby road looking back towards entrance. Location is near stake #57 as numbered on Cad drawing. Road design data are available from # 57 back towards lobby. Conditions are easy and straightforward such that no survey nor design is required to build the rest of the road to connect it to the entrance. Marking general alignment/location on the ground (for example by Ivan) is adequate to proceed with construction Figure 21: The bridge abutment across the Panamaes would be upstream, to the left of the tree in the center to allow for abow-like alignment of the road upstream in the flood plain to direct highwater to the two bridges, this one and the other one where currently an old concrete culvert is located. Details can be found in the attached drawing below Page 10

11 Est. Nº43 Est. Nº45 Est. Nº 53 Est. Nº 52 Est. Nº51 Est. Nº 50 Est. Nº 49 Est. Nº48 Est. Nº 47 Est. Nº 46 Est. Nº44 Est. Nº 42 Est. Nº41 Est. Nº40 Est. Nº 39 Est. Nº PB-1 PB-2 PB-3 PB-4 PB-5 PB-6 PB-7 Elev= Elv.= Elv.= Elv.= Elv.= Elv.= Elv.= A E E E E E KBZAL KBZAL KBZAL.F 3.96 KBZAL.F 4.82 KBZAL 4.86 KBZAL CERCA 5.24 CERCA 8.89 CERCA B.QBA 4.07 B.QBA 4.24 B.QBA 4.28 B.QBA 3.98 B.QBA 4.03 B.QBA E E E E AUX 5.53 AUX 5.59 STAR STAR STAR STAR STAR STPQ STPQ STPQ STPQ STPQ STPQ STBQ STBQ STBQ STBQ STBQ STBQ ST ST ST ST ST ST ST ST ST ST ST STPI STPI STPI STPI STPI STPI ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST STPI PI ST ST ST STBQ STPQ STPQ STBQ ST ST ST ST ST ST ST ST STPQ STPQ STPQ STPQ STPQ STPQ STBQ STBQ STBQ STBQ STBQ STBQ STBQ ST ST ST ST ST ST ST ST ST ST STAR STAR STAR STAR STAR STAR STAR STAR STAR STAR

12 6. Sunset Beach Sunset beach issues were reviewed on location with Andrew and Edwina on Issues were drainage from natural draw as well as from public road. A series of small check dams (earth structures with live vegetation, maybe meter in height can be constructed to catch run-off in settlement ponds. Ditch water from the public road can be diverted into these ponds and then a ditch line (culvert with overflow structure drain clear water back into the ditch line for the last 50 nor so meter down to the beach. Clearance above public road should be adequate to allow for pick up vehicles to pass underneath and accommodate resort facilities above (see attaché figure sunset beach) Page 11

13 S PE DA A CH UM IC O SE I V R M U D E R B FINCA 542 A AREA INSCRI 5 HAS