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r Department of Fisheries & Oceans Harbours & Infrastructure, Grand Falls, NF.

THE DESIGN OF A FOR

SNOOK'S ASV", NEWFOUNDLAND

13 August, 1990 Douglas G.Skinner

TA 770 S5 21932:7.

Department of Fisheries & Oceans, Harbours & Infrastructure Branch

Grand Falls, Newfoundland

111E DESIGN OF A GABION RETAINING WALL FOR

SNOOK'S ARM, NEWFOUNDLAND

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Division of Co-operative Education et1 er.:1-n Memorial University of Newfoundland St. John's, Newfoundland

13 August, 1990 Douglas GiSkinner TABLE OF CONFERS PAGE

LETTER OF TRANSMITTAL TABLE OF CONTENTS (i) SUMMARY 1.0 NEEDS ANALYSIS 2

1.1 General 2 1.2 Fishing Activity 2 1.3 Existing Facilities 2 1.4 Slope Failure at the Truck Turnaround 3

2.0 SITE PREPARATION 6 2.1 General 6 2.2 Initial Stadia Survey 6 2.3 Dredging 6 2.4 Final Stadia Survey 7 3.0 GABION RETAINING WALL 9 3.1 General 9 3.2 The Case For 9 4.0 DESIGN 12 4.1 General 12 4.2 Engineering Properties 12 4.3 Fundamentals of Gabion Retaining Wall Design 13 4.4 The Plan and Cross Section 14 5.0 RESULTS 16 5.1 General 16 5.2 Design Calculation Results 16 5.3 Cost Estimate 18 5.4 Tender Documents 19 CONCLUSION 21 REFERENCES 22 APPENDIX A : Maccaferri Gabion Installation Guide 23 APPENDIX B : Calculation Sheet 29

APPENDIX C : Detailed Cost Estimates 33 APPENDIX D : Invitation to Tender & Tender Documents 34 The at the edge of the newly constructed truck turnaround in Snook's Arm collapsed this past Spring. In order to provide enough room for a truck from the National Sea fish plant in nearby LaScie to maneuver when it arrives to collect each day's fish landings, the bank must be rebuilt. A rock filled gabion wall is proposed to solve this problem for socio-economic reasons. The installation of gabions requires very little skill and the local unskilled labour force could be employed to work on this project when the fishing is slack. Such employment is eligible for funding through various Federal Government Agencies. Even if the locals are unavailable for work on this job, it is still a worthwhile pursuit to utilize gabions as an experiment to determine the feasibility of installing gabions on future projects, since this project is very small and low in cost. The engineering properties of a gabion manufactured by Maccaferri Gabions of Canada Ltd. are suited to this project. The gabions are constructed of hexagonal zinc coated steel wire mesh with a PVC coating applied for further protection in the corrosive marine environment. The individual gabions are filled with rock and wired together to form a flexible and permeable structure which - is capable of resisting any type of stress. The wires act as reinforcement and a gabion structure becomes stronger and more efficient with age. The gabion retaining wall designed for Snook's Arm will effectively resist failure by overturning, sliding, and settling. The design calculations show this unambiguously. The project could be constructed for under $5,000.00 if local labour was available. Since this is not the case, tender documents have been prepared for local contractors to prepare bids for this work. It is expected that the cost will be 30 to 50% higher than estimated. It may not be possible to finance this project from the 0 &M budget of 1990. This means that the rebuild of the truck turnaround in Snook's Arm may have to wait for funding from next year's budget. More damage and higher repair costs will result if the work is not completed before next spring. 1.0 NEEDS ANALYSIS

1.1 General

This section of the report deals with the present state of the harbour facilities at Snook's Arm and identifies the need to rebuild the truck turnaround area near the wharf.

1.2 Fishing Activity

The community of Snook's Arm is located on the western side of Green Bay, approximately 18 kilometers from LaScie. The fact that there are 26 full and part-time fishing licenses issued for the 1990 season from a total population of 57 is indicative of the importance of the fishery to this village. For the past five years the fishermen of Snook's Arm landed an average of 150,925 killograms of all species of fish with an average yearly value of $115,450.00.

1.3 Existing Facilities

The most important criteria for the allocation of funds for the upgrade of any facility are safety and efficiency for use by fishermen. By 1988 the wharf at Snook's Arm had deteriorated to the point where it was no longer considered safe for use. For this reason and the fact that the community itself would probably not survive without a proper wharf, a new treated timber wharf was constructed last year at a cost of $490,000.00. The construction of this wharf ensured the survival of the community and provided the facilities for the local fishermen to operate safely and efficiently.

During the construction of the new wharf, it was suggested by the local Fisherman's Committee that the approach to the wharf be widened to provide a truck turnaround area. The landings at Snook's Arm are stored on ice in containers at the wharf for collection by a straight body truck from the National Sea Products Fish Plant in LaScie. The driver 3 had to back up to the wharf because the approach was not wide enough for turning. This meant that he had to turn around at the top of some very steep hills above the village. It was easier for the truck to negotiate these steep hills in reverse gear going down the hill empty than to have to do so going up with a load. Since the contractor was already on site to construct the wharf, it was decided to proceed with the construction of the truck turnaround at that time to avoid extra mobilization and administration costs associated with hiring another contractor at a later date.

The truck turning area that was constructed was a compromise with what the Fisherman's Committee suggested and the budgetary constraints of the Department. At a cost of $36,500.00, a 20 foot long section of treated timber retaining wall with associated rock and fill was constructed adjacent to the wharf. This campramise provided enough room for the trucks to maneuver, while the timber retaining wall kept the backfill from reducing the water depth at the wharf, thereby maintaining the amount of berthage available to users. Beyond the retaining wall, the backfill was allowed to slope to the water's edge. The embankment so formed followed a curvilinear shape towards a privately owned shed across from the wharf. The original suggestion called for a 40 foot section of timbei retaining wall and the embankment was to proceed straight across the shoreline. This proposal was estimated to cost $53,000.00.

1.4 Slope Failure at the Trick Turnaround

Over the past winter, the embankment at the edge of the newly constructed truck turnaround area and adjacent to the timber cribwork retaining wall collapsed. Sufficient room is still available for the National Sea Products trucks to maneuver adequately. However, the deterioration of the slope caused other difficulties that need to be addressed.

Much of the backfill material adjacent to the retaining wall at the wharf fell into the water in front of the retaining wall. This 4 deleterious material severely hampers the safe mooring of boats near the end of the wharf. During low tide, the water depth in this location is insufficient for vessels to maneuver without striking the rocks. The fishermen avoid this area and, as a consequence, at least two berths are unavailable for use. This material must be dredged out as soon as possible.

When the slope of the bank collapsed at the shoreline, the guardrail installed at the top of the bank was left suspended between the first and last posts. This is evident from Photo # 1 below.

Photo # 1: Slope Failure at Truck Turnaround - Snook's Arm

Four posts are left suspended in air. This could be a safety hazard to anyone who is unfamiliar with the washout and who decides to visit at a time when the lighting is dim, say early morning or late evening. This person could quite conceivably drive a vehicle over the bank. Granted, the chances of this happening are quite miniscule, but the hazard should still be addressed.

A more insidious difficulty exists in the natural processes of nature. The spring run-off will further erode the bank to the point where the available space for trucks to turn is considerably reduced. 5 Furthermore, the forces exerted by the trucks themselves can lead to greater slope failure.

The foregoing arguments lead to the inescapable conclusion that the bank must be rebuit so as to maintain the advantages that the original construction was supposed to provide. Yet, the proffered solution must ensure that the problem does not re-occur for a reasonable period of time. The cost to repair the damage should be reasonable. 2.0 SITE PREPARATION

2.1 General

This section of the report is concerned with the collection of information pertaining to the physical layout of the site before and after the spoil that had fallen from the bank was excavated.

2.2 Initial Stadia Survey

In order to get a full appreciation of the extent of the damage to the slope, a stadia survey was conducted on June 26, 1990. At that time a temporary bench mark was chosen on the top of the timber retaining wall at the northeast corner. Since the location of an established datum was unknown, the elevation for this TBM was chosen arbitrarily as 5.00 meters above sea level. Later, a datum was found and the elevation was transferred from this Bench Mark to the TBM. The notes were revised with the true elevations replacing the assumed elevations. This information was used to establish the plan and slope at the top edge, middle, and bottom of the failed embankment. This data would be useful for the preparation of working drawings that would be utilized by a contractor to repair the damaged bank.

2.3 Dredging

The most urgent need at Snook's Arm was to have the spoil from the collapsed bank dredged in order to increase the usable berths at the wharf. Before any disturbance to coastal waters such as dredging can be performed, permission must be obtained from the recently formed Water Investigations Division of the Provincial Department of the Environment. Although the necessary application was send on May 30th and approved on June 4th, the dredging operation did not commence until July 5th. The reason for this delay was that the contractor was engaged on other jobs. It was necessary to wait for this contractor, James G. Reid & Son, because the backhoe that this company owned had a 60 foot reach. The 7 extraordinary reach enabled the operator to dredge a significant area from the shore without having to enter the water. This was an important consideration of the Environment people since it minimized the amount of turbidity in the water which would result in quicker dissipation and hence, minimal damage to any fish habitat in the immediate vicinity. The following photograph (#2) shows this backhoe in operation at the site.

Photo * 2: Dredging Operations at Sdook's Arm (July 5, 1990)

In addition to the removal of spoil material near the wharf, the backhoe operator was asked to collect the material that had fallen from the bank into the bay. This material was stockpiled on the opposite shore to be reused as backfill when the bank was refurbished. Photo # 3 on page 6 shows the state of the site at the completion of the dredging. The stockpiled material is clearly evident.

2.4 Final Stadia Survey

On July 11th, a stadia survey was conducted to determine the alterations to the embankment as a result of the dredging. Also, the physical layout of the buildings, wharves and edges of the gravel 8

Photo It 3 : Snook's Arm Site - After Dredging, July 5, 1990 approach were determined in order to draw an accurate plan of the site as it now exists. The drawing generated from the accumulated site information is contained in a pocket on the inside of the back cover. The title of this drawing is "Site Plan (After Dredging)" and the drawing is numbered GF -0470 -101, Rev.C.

At this point, the necessary site information collected was sufficient to investigate the alternative solutions available to rebuild the damaged embankment at a reasonable cost. 3.0 GABION RETAINING WALL

3.1 General

It is usual Engineering procedure to define the parameters that are to govern the selection of materials and, on the basis of the established criteria, - the optimum choice is made. The situation at Snook's Arm is significantly different in that the District Manager, who is responsible for this community, viewed this circumstance as an opportunity to install a rock filled gabion wall to rebuild the truck turnaround. The reasons why the District Manager made this choice are explained in this section of the report. Furthermore, a comparison of the alternatives to gabions are discussed in terms of these arguments.

3.2 The Case For Gabions

Traditionally, a problem of the nature of that encountered in Snook's Arm would have been solved in one of two ways. Either a retaining wall would have been constructed from treated timber crib- work or the slope would have been rebuilt at a suitable incline with the new bank stabilized by the installation of armour stone. In this case, the choice of an armour stone covered embankment is not viable since the original bank which failed was constructed in this fashion. The potential for a re-occurrence is significant enough to eliminate this option. A more permanent solution is possible through the installation of a retaining wall.

In recent years, gabions have become a popular choice for civil projects requiring slope stabilization. Gabion walls are modular structures formed of rectangular cages formed from zinc coated steel wire mesh which are filled with rock of the proper size and mechanical properties. The individual modules are wired together with zinc coated wire in such a way as to form a monolithic structure. For a variety of reasons, the District Manager of Harbours & Infrastructure Branch endorsed the use of gabions from which to construct a retaining wall at 10 the Snook's Arm site. For the most part, the selection of this material was based upon socio-economic considerations.

The construction of treated timber cribwork requires that the builder is skilled in rough carpentry or joinery and is experienced in cribwork construction. Communities as small as Snook's Arm rarely have an adequate supply of skilled tradespeople to properly construct a crib- work structure. Therefore, a contractor is hired and, as a result, the direct economic benefits in the form of wages accrue to workers from outside of the community. When the fishing is good, virtually the whole population is working in the fishing industry and construction projects are of no interest to the community in terms of employment. When catches are poor, some form of Government assistance is required to provide an income until the next fishing season. The installation of rock filled gabions is considered a low technology task with no formal trades training required. This type of construction is ideal for funding from such Federal Government programs as Canada Works or Community Futures. The citizens of the community could, during a downturn in the fishing industry, benefit economically from employment on projects of this nature as well as benefiting from the products of their labour.

The use of gabions in this project also have certain logistical advantages. While most of the spoil from the dredging operations can be reused as backfill, the balance required will have to be imported. This is not the case for the rock needed to fill the gabions. Before Route 416 was constructed, the community of Snook's Arm was spread out along the sides of the Arm from which the village takes its name. A footpath had been built many years ago to facilitate visits between widely separated neighbours. The slope of this footpath was protected from erosion by fractured sandstone from the surrounding cliffs. This material exists in sufficient quantities and in just about the perfect gradation of particle sizes for use in the gabions. This material is evident in Photo # 3 on page 7, to the right of the arm of the backhoe, immediately above the dredged spoil. This fractured sandstone is ideal for use in the gabions with a minimum of sorting required to remove undersized and oversized particles. Even though there is an abundance 11 of the sandstone beneath the cliff, it may not be possible to excavate the full amount required because the slope is quite steep for a rubber tire backhoe to access. Still, the amount needed to be imported should be minimal as a fair amount of the rock is well within the reach of the backhoe.

The availability of this local sandstone enhances the viability of utilizing gabions in terms of asthetics. The local sandstone will blend in quite naturally wilh the local and will not appear to be an intrusion.

Cost estimates for the construction of the retaining wall from timber were not prepared for comparison to the estimate for a gabion structure. From the quotations of prices fran Public Works of Canada for the estimated costs of other projects sponsered by Harbours and Infrastructure Branch, it is evident that the installation of gabions is much less than the cost of installation of an identical structure constructed from treated timber. For example, the estimated cost of construction of a gabion structure to repair the approach to the wharf in the community of Trinity, Trinity Bay was $85,000.00. The estimate for an identical structure constructed from treated timber cribwork was $123,000.00. From other such quotations on file in the Grand Falls Office of Harbours and Infrastructure, the general impression is that treated timber construction is approximately 35 to 45 % more expensive.

Finally, the size of the project itself was one of the determining factors in selecting gabions as the preferred material. It is quite a small project and should not be beyond the funding capabilities of the Branch. This small project is an experiment and, if successful, it will serve as a model for future larger scale projects. 4.0 DESIGN

4.1 General

This part of the report discusses the final design for the Snook's Arm project. The engineering properties of the gabions manufactured by Maccaferri of Canada are elucidated. An overview of gabion retaining wall design is explained. The Plan and Section of the design are devised and explained in reference to the morphology of retaining wall design and the specific parameters of the site conditions.

4.2 Engineering Properties

The only supplier known to Harbours and Infrastructure Branch at this time is Maccaferri Gabions of Canada Ltd. Therefore, it was not possible to compare products offered by competing companies to select the most promising. The District Manager is well satisfied by Maccaferri's prices and the support offered by this company in terms of technical literature and advice. The installation instructions are easy to understand and unskilled labour should have little difficulty in unpacking and installing the gabions. This is exactly what is required. A copy of the installation instructions published by Maccaferri Gabions of Canada Ltd. is located in Appendix A of this report, (pages 22 - 27).

Maccaferri Gabions are defined as a rectangular container, comprised of steel wire woven in a uniform hexagonal triple twist pattern, reinforced on the corners and the edges with heavier wire. All wires are coated with high quality zinc for corrosion resistance. The wires in the sea type gabion are additionally coated with polyvinyl chloride to increase the ability of the gabions to withstand the corrosive marine environment.

One of the principal properties of a structure composed of this material is the inherent flexibility of the structure. The wall can yield to earth movement while retaining its full efficiency and structural soundness. The ability of the gabion structure to deform 13 when stressed does not diminish the strength of the wall but increases it by drawing into action all of the resisting elements.

The gabion structure is, in effect, a reinforced structure capable of resisting any type of stress, particularly tension and shear. The wire mesh not only contains the rock, but also provides a comprehensive reinforcement throughout the structure.

The gabion retaining wall is permeable. The ability of the structure to collect and carry away ground water eliminates one of the principal causes of instability. This property is the most important consideration for the retaining structure to be constructed in Snook's Arm. The drainage function is augmented by evaporation generated by the natural circulation of air through the voids between the filling stones.

The efficiency of a Maccaferri gabion structure increases with age. will collect within the voids and vegetation will grow which further solidifies the structure.

4.3 Fundamentals of Gabion Retaining Wall Design

A gabion retaining wall is regarded as a mass gravity structure. The wire mesh is considered to be an additional safety factor and is not included in the design considerations. The cross section of the retaining wall is selected and the active soil pressure behind the wall is calculated using the Coloumb Wedge theory and the mass of theliall is designed to balance the force exerted by that soil wedge. The calculation of the active thrust of earth against the wall takes into account the soil characteristics, the slope of the backfill and any superimposed loading. The active thrust is considered to act at one third of the vertical height from the base.

The stability of a retaining wall is measured by its ability to resist overturning, sliding, and settling. Each of these parameters is discussed below. 14 Overturning: The coefficient of stability is the ratio of the restoring moment to the overturning moment taken about the hinge point. This ratio must be greater than the safety factor of 1.5. Sliding: The ratio of the normal and tangential components of the active thrust must also be greater than the safety factor of 1.5 Settling: The maximum pressure distribution must not exceed the safe load of the soil. The pressure distribution is assumed to be linear and the resultant of the forces passes through the base within the middle third.

To increase the stability of the gabion retaining wall, Maccaferri's Technical Adviser suggested that the wall should be tilted back into the bank at an angle of 6 degrees ( or a 1 in 10 slope).

The actual calculation data for the gabion retaining wall planned for Snook's Arm are discussed in Section 5 of this report.

4.4 The Plan and Cross Section

The plan developed for this project also did not follow the original request of the Fisherman's Committee. The area for turning trucks provided was ample before the slope failed. The intention of this new design was to add a 20 foot gabion wall adjacent to the existing treated timber cribbing. The embankment would be rebuilt beyond the gabion wall as it was before. After the cost estimates for this proposal were prepared, it was decided that sufficient funds were available to totally retain the embankment with a gabion structure extending the full length of the seaward border of the turnaround. The final plan developed calls for the gabion wall to align with the cribwork for a 6 meter length. The final 10 meters of gabion wall would join the end of the 6 meter length at an angle of 45 degrees. The drawing showing the plan, section and elevations of this design is found in the pocket inside the back cover of the report (Drawing # GF - 0470 - 102, Rev.C).

Maccaferri's Technical Adviser assured that cutting the gabions on 15 site and joining the pieces together at an angle is usual practice and could be accomplished with little difficulty. The structural properties of the gabions will not be compromised providing that sufficient overlap is provided for the joins. To further facilitate installation, the gabions will be and joined temporarily at the Harbours and Infrastructure Warehouse before they are shipped to the site.

The section was developed in consultation with Maccaferri and on the basis of the design computations. Although the foundation upon which the structure is to rest is quite strong (mostly ), there are some pockets or depressions which must be filled to prevent differential settling at these locations. As long as these dips are relatively small and the base below these depressions is composed of a strong material, then these pockets can be filled with crushed stone to provide uniform grades upon which the entire gabion structure will rest. 5.0 RESULTS

5.1 General

This final section discusses the results of the design calculations in the context of the assumptions made regarding the characteristics of the soil conditions expected. The decision to invite tenders for the project is explained and the cost estimates for the job are given.

5.2 Design Calculation Results

A principal difficulty encountered in the preparation of the design calculations is that the exact characteristics of the soil to be used as a backfill material are unknown. The backfill will be supplied by others according to specifications stating the properties desired. The actual properties of the soil to be supplied will be unknown until suitable arrangements can be made to test this material. In terms of the design computations, certain assumptions have to be made.

The angle of internal of the backfill is assumed to be 15 degrees. For the type of soil to be supplied this angle is unusually low. The angle of internal friction directly relates to the shear stress of the soil at failure with lower values of the angle correlating with lower values of shear stress. The internal angle of friction is not an inherent material property but is dependent upon the conditions operative in the test. Therefore, it is likely that a range of values for the friction angle will be obtained as testing conditions are varied. The value chosen for the internal angle of friction represents the lowest acceptable value for the backill as it is prudent to design the structure on the basis of the soil failing at relatively low shear stress levels. Since the soil expected to be supplied should be able to tolerate greater shear stress, the design thus formulated will provide greater values of safety factors than originally calculated.

The mass of the backfill is also unknown. For the purpose of computations, a value of 2,500 kg/m3 for the unit mass of the soil was 17 chosen. This value is unusually high and is equivalent to the density of hard limestone. The soil to be used will most certainly will not be as dense. In selecting this high value, the design is based upon its ability to withstand greater loads than those expected. Once again, the safety factors will increase.

For the purpose of calculation, the angle of wall friction is assumed to be equal to the angle of internal friction of the backfill. The load imposed on the soil by the wall acts at an angle with the perpendicular to the soil-wall interface and in such a way as to oppose any motion. In gabion walls this angle of wall friction can be assumed to be equal to the angle of internal friction due to the considerable roughness of the gabion surface. Therefore, the soil-wall interface can be considered to be a soil to soil surface.

The range of values to be expected for the load bearing capacity of the foundation soil is between 10 and 20 thousand kilograms per square meter. The foundation soil is composed of bedrock, so the higher end of this range should be applicable. For additional safety, however, the lower value has been assumed.

The fractured sandstone to be used'as filler for the gabions is to contain particle sizes graded between a maximum size of 200 millimeters and a minimum size of 75 mm. The void space for this gradation is assumed to be 30 % as suggested by Maccaferri Gabions of Canada Ltd. The unit mass of the gabions is 30 % less than the solid unit mass of sandstone (30 % Of 2,300 kg/i), or 1610 kg/e.

Detailed calculations based upon the foregoing assumptions are contained in Appendix B, (pages 28 - 31). The results of these computations show factors of safety of 2.98 for overturning and 1.90 for sliding. These values are greater than the recommended factors of safety of 1.5 for each of these parameters. Therefore it is unlikely that the wall will fail by overturning or by sliding.

The pressure distribution at the heel and toe of the foundation of 18 the wall equals 5,690 kg/ml and 1010 kg/m; respectively. Since these values are less than the assumed value for the bearing capacity of the foundation soil, the wall is safe from failure by excessive settlement.

5.3 Cost Estimate

The installation of the gabion retaining wall will increase the area available to the truck turnaround to approximately 75 % of the original request by the Fisherman's Committee. Therefore, it is reasonable to assume that the project is viable in strict economic terms if it can be constructed for less than 75 % of the difference between the original estimate and the cost of the construction of last year. This amounts to less than $12,375.00.

The detailed cost estimates for this project are found in Appendix C on page 32, which illustrate a total estimated cost of $4,894.94. This estimate does not include the cost of additional guardrail required, nor the cost of freight for shipping the gabions from the factory to the warehouse. The estimate was prepared with the understanding that the project was to utilize local labour at a wage rate of $8.00 per hour, and the hire of a contractor to supply the construction equipment as well as the fill materials. This estimated amount is within the ability of the Harbours & Infrastructure Branch to fund from this fiscal year's operating and maintenance budget. Unfortunately, it is expected that the project will actually cost more than this figure.

The prices used in this estimate for the contractor supplied material and machinery are based on an average of prices obtained from several Grand Falls construction companies. While the costs of construction equipment should be comparable for construction companies in Green Bay, the prices for the fill materials can be significantly higher. Such prices will depend upon the availability of the specified materials as well as the distances along which these materials would have to be transported from the pit to the site. 19

The fishermen of Snook's Arm are experiencing a productive and potentially lucrative season. Those that aren't fishing are getting full time employment at the National Sea Products fish plant in nearby LaScie. It is highly unlikely that the project will be able to make use of local labour as intended. This means that a contractor will have to be hired if the project is to proceed this year. The wage rates are higher for a contractor, even if the company is nonunion, since the contractor will charge a mark-up on the wages for the company's profits. This translates to higher costs in the order of 30 to 50 %.

5.4 Tender Documents

It is unlikely that the contractors from the Green Bay area of the province will be familiar with the use and installation of gabions. The scope of work which is intended to serve as the specifications for this job have been written rather informally and less rigorously than usual. The job is really quite simple and a more formal, rigid language in the specifications may only serve to increase the tendered prices. The small contractor may be intimidated by the legal sounding diction since he is venturing into unknown territory. The job may appear to be more technical than it actually is. The scope of work as well as a copy of the letter of invitation to tender for this job is located in Appendix D, (pages 33 -38). These documents are a compromise between the need to provide a measure of protection for the concerned parties and to give a fair opportunity to small contractors who may be discouraged by formal technical language.

The date for closing of the tender process is 4:00 PM on the 20th of August, 1990. The job is tentatively scheduled to commence at 8:00 AM on the 27th of August. The commencement of the project depends upon the availability of funds to finance the construction, since it is expected that the tendered lump sum price will be greater than the amount available from the operating and maintenance budget for this year. Once the bids are collected and the bottom line figures are known, permission will have to be sought from the Director of Harbours & Infrastructure Branch for the additional funding requirements. It may 20 be the case that the truck turnaround will have to take its place on the priorities list which means that this project may be placed on hold for inclusion in next year's budget. CONCLUSION

The truck turnaround at Snook's Arm should be repaired as soon as possible, certainly before next spring when the spring run-off will surely cause more damage. Any further damage to the turnaround will significantly increase the cost of repair.

This report has shown that the installation of a rock filled gabion retaining wall is technically and economically feasible. It is the best possible alternative available to provide a sound engineered structure to rebuild the embankment and to prevent any further re-occurrence of damage for many years to come.

The use of gabions to solve this problem is a worthwhile exercise in order to determine the suitability of utilizing gabions for future similar projects of greater scale and complexity. As an experiment, this project offers an opportunity to extend the technical competence of the staff of the Grand Falls Office of the Harbours and Infrastructure Branch.

The potential use of local labour and materials increases the attractiveness to Harbours and Infrastructure of utilizing gabion structures for this and future projects. Local labour can be hired on similar projects when the fishing is poor since no skill is required to install the gabions. The use of local rock as a filler for the gabions affords a structure that is not only functional but extremely attractive and distinctive as well. (1)Gabion Retaining Walls, pamphlet, by Maccaferri Gabions of Canada

(2)Flexible Gabion Structures in Earth Retaining Works, by R.Agostini et al, Officine Maccaferri S.p.A., Bologna, Italy MACCAFERRI GABIONS METHOD OF CONSTRUCTION RIVER TRAINING EARTH CONTROL CHANNEL LINING

LANDSCAPING BRIDGE AND CULVERT PROTECTION MARINAS FOREWORD

MACCAFERRI GABIONS

could be the best answer for your next project. Gabion installations are more economical than rigid or semi-rigid structures. Maccaferri Gabions, delivered in handy collapsed form, are easily assembled and require no technical skill to erect. Filled with stone, they become a large, flexible and permeable building block from which a broad range of structures may be built.

Maccaferri Gabions' design and construction assure strength and lasting effectiveness. No footings are required. They are completely unaffected by frost heave and because they are porous, they are self-draining and hydrostatic heads do not develop behind them.

Further reliability is assured by Maccaferri Gabions flexibility. Each unit yields to earth movement to retain its full efficiency while maintaining its structural integrity. In the long term picture, gabion efficiency increases with age. Silt and neighbouring earth build up between the rock fill, vegetation takes root and the entire gabion structure solidifies into a durable and eye-pleasing form. Overall there is no other type of structure to match this system for economy, performance and appearance.

Published by the Technical Department of MACCAFERRI GABIONS 2 Prepared and Edited by J. D'ADDARIO Definition

M;=,L7,..,FERRI GAL,C;r. 4

Is a rectangular container made of steel wire, woven in a uniform hexagonal triple twist pattern, reinforced on corners and edges with heavier wire.

Advantages of MACCAFERRI GABION Structures

FLEXIBILITY

A Maccaferri gabion structure, because of its inherent flexibility, can yield to earth movement and still retain its full efficiency and remain structurally sound. The gabion structure which "bends without breaking" is quite unlike rigid or semi-rigid structures which may be completely lost when even A Maccaferri Gabion subjected to 48,000 lbs. load test. slight changes occur in their foundations. The building block method of construction also lends itself to unlimited flexibility of • design.

PERMEABILITY

The Maccaferri gabion structures are highly permeable and act as self draining units which "bleed" off ground waters, relieving hydro- static heads.

DURABILITY

A Maccaferri gabion structure is a heavy, monolithic gravity unit able to withstand earth thrust. Its efficiency increases instead of decreasing with age. Silt will collect within the voids and vegetation will grow, further solidifying the structure. To enhance ap- pearance and to minimize voids, hand place- ment of stones along the exposed faces of the baskets is recommended.

3 MACCAFERR1 GABIONS

1 ••

RIVER TRAINING

Maccaferri Gabion Structures offer, in many instances, the most technical and economi- cal solutions to problems of stream modification and control

CHANNELS

Maccaferri gabions channel lining forms a monolithic protection which can withstand earth thrust, eliminate underground water and is unaffected by frost heave and ice action.

4 p] APPLICATIONS

LANDSCAPING

Maccaferri Gabions, with their natural appearance, maintain the natural environment of the area. They can he used in parks, highways and around bridge approaches, to create walkways and to beautify the banks of lakes and ponds. Their application in landscap- ing is limited only by the ingenuity of the landscaper.

RETAINING STRUCTURES

Maccaferri Gabion Retaining Structures combine retaining and draining features. They are quickly erected, are pervious and are reinforced to tolerate settlement without fracture. Expensive, and some- times dangerous, excavation for foundation is not required.

5 MACCAFERRI GABiONS are ideally suited for MARINAS

1. When they are installed, their natural attractive appearance will blend with any location and surrounding.

2. They can absorb surf action and small wave swash.

3. They can be used in new projects or connected with other types of existing structures.

4. They can be used in small or large projects by government agencies, clubs or by private individuals.

BRIDGES

Maccaferri Gabions are also used for the protection of bridge embankments and to build wing walls and support- ing abutments for bridges carrying light traffic on highways as well as in parks and rural areas.

LAKES

Public, as well as governmental agencies, have voiced a demand for lake frontal land restoration and re- clamation projects. The financial and recreational value of these properties has risen year after year. Erosion and subsequent loss of this type facility has become a major problem. Maccaferri gabion principle offers an effective and economical solution.

6 ASSEMBLY AND INSTALLATION

PACKING . For ease of handling and shipping the gabions are supplied folded flat. See picture 1.

A colour stripe applied on the side of each folded gabion identifies the size. See Picture & table • 1 Picture No. 1 Assembly 1) Open the bundle and unfold each unit. 2) Lift the sides, the ends and diaphragms into vertical position. Fig. 2. 3) Wire the four corners together and the edges of the diaphragms to the gabion sides. Fig. 2 and 3.

Picture No. 4

Fig. No. 2

t Installation double 1009

1) Level the base where the gabions will be placed to a smooth finish si ngle I00 and the right elevation. See pic- ture =4.

2) Each unit should be securely wired to the adjacent units along the top and the vertical edges Fig. No. 3 prior to placing the 3" to 8" stone. To achieve better align- ment and finish, the gabions can be stretched before filling.

3) Where permitted by the thickness of the structure, the gabions can be placed back to back and front to front to facilitate the filling and closing of the lids. Fig. 5

4) After filling has been completed, the top is folded shut and wired to the ends, side and diaphragms. Fig. 6 Fig. No. 6 5) Empty gabions placed on top of a completed row must be wired to the filled gabions at front and back. Fig. 5 Picture No. 5

7 -2, C I0 SIZES

METRIC SIZES

CAPACITY Length—Width Approximate Depth In equivalents In No. of Cubic Cubic Color Code Meters Feet Diaphragms Meters Yards

2x1x1 6'6"x3'3"x3'3" 1 2 2.816 BLUE 3x1x1 9'9"x3'3"x3'3" 2 3 3.924 WHITE 4x1x1 13'1"x3'3"x3'3" 3 4 5.232 BLACK 2x1x.5 6'6"x3'3"x1'8" 1 1 1.308 RED 1.962 GREEN 3x1x.5 9'9"x3'3"x1'8" 2 1.5 4x1x.5 13'1"x3'3"x1'8" 3 2 2.816 YELLOW 2x1x.3 6'6"x3'3"x1' 1 0.6 0.785 BLUE•RED 3x1x.3 9'9"x3'3"x1' 2 0.9 1.177 BLUE•YELLOW 4x1x.3 13'1"x3'3"x1' 3 1.2 1.570 BLUE-GREEN

IMPERIAL SIZES ALSO AVAILABLE IN P.V.C. COATED WIRE

Capacity Number of Length Width Height Cubic Color Code Diaphragms Yards

6' 3' 3' 1 2.0 BLUE 9' 3' 3' 2 3.0 WHITE 12' 3' 3' 3 4.0 BLACK 6' 3' 1'6" 1 1.0 RED 9' 3' 1'6" 2 1.5 GREEN 12' 3' 1'6" 3 2.0 YELLOW 6' 3' 1' 1 ' 0.66 BLUE-RED 9' 3' 1' 2 1.0 BLUE-YELLOW 12' 3' 1' 3 1.33 BLUE-GREEN

SPECIFICATIONS

RIVER TYPE SEA TYPE Hexagonal, approx. 3" x 4" Mesh opening: Hexagonal approx. 3" x 4" 0.116" diam. Wire for netting: 0.1062" diam. plus 0.02" PVC a 152" Wire for selvedges 0.1338" diam. plus 0.02" PVC 0.086" Wire for binding: 0.086" diam. plus 0.02" PVC .85 ounces per square foot Zinc coating: .80 ounces of zinc per square foot plus 0.02" of Polyvinyl Chloride Plastic

MACCAFERRI GABIONS of CANADA LTD. TORONTO: 797 Don Mills Road, Suite 803, Don Mills, Ontario M3C 1 V2 (416) 429-3380 Fax: 429-0639 Telex (Toronto) No. 06-966885 MONTREAL: 7105 St. Hubert — Suite 301, Montreal, Quebec, H2S 2N1 (514) 270-5695 Fax: 270-6266 VANCOUVER: 736 Granville Street, Suite 613, Vancouver, 11.C. V6Z 1 G3 (604) 683-4824 Fax: 683-7089 EDMONTON: 10548 — 82 Avenue, Edmonton, Alta. T6E 2A4 (403) 433-1704 HALIFAX: 1541 Birmingham Street, Halifax, N.S. (902) 434-0503 PRINTED IN CANADA 29

CALCULATION SHEET Page 1 of 4

Department of Fisheries & Oceans, Harbours & Infrastructure Branch Grand Falls, Newfoundland

Project : Gabion Retaining Wall - Snook's Arm, Newfoundland

Designed By : Douglas G.Skinner Date : 17 July, 1990

DATA :

a). Wall b).Soil h = height of gabion wall 0 = internal angle of friction B = width of base E = slope of backfill A = area of cross section = angle between the line H = height where active connecting the top to the thrust acts bottom corner, and the bi5= unit mass of gabion horizontal F = fulcrum point = angle of wall friction X = horizontal dist.to G Cs= unit mass of soil Y = vertical dist.to G Ks= bearing capacity of roi:= angle of battered wall foundation soil

Substituting values: h = 2.5m B = 2.0m A = 3.5m H = 2.486 .n X = 1.132m Y = 1.162m 0= 15° 4 = 0. A = 85.5° g = 6° S =15 . )'s = 2,500 kg/m3 * Ks = 10,000 kg/m2

Assumptions : 1.Since the earth thrust is exerted on a soil to soil plane, assume 56=8. 2.Assume i(s = 2,500 kg/m3 3.Assume K5 = 10,000 kg/ma 4.Assume void space within the gabions is 30 % : Unit mass of gabion wall = unit mass of sandstone - 30 % = 2300 - 2300 x 0.3 = 1610 kg/m 3

Calculation of Ka , the coefficient of active earth pressure, where

Sint (p ) Ka= Sin( p5+ S )Sin(0 - E) Sina (73 )Sin(p -6)

E )Sin(i3 +E.)

30 CALCULATION SHEET Page 2 of 4

Ka= Sin (85.5+15) 2 Sin (85.5)Sin(85.5-15) [1 +/Sin(15+15)Sin(15-0) ./Sin(85.5-15)Sin(85.5+0)

Ka= 0.550 Calculation of active earth pressure, Ro Pc:= 1/2( 6, )(1)z (KO * (2,500) * (2.486) * (0.550) = 4,250 kg/m Components of P : Ph = Pa * cos( --co Pv = Pa * sin(5 = 4,250 * Cos(15 -6) = 4,200 * Sin(15 -6) = 4,200 kg/m = 665 kg/m

Mote : All moments are Calculation of moment arms, d, s, s' , s" : taken about fulcrum point F d = H - B * Sin(000 s' = X * Cos(0() 3 = 1.132 * Cos(6) = 2.486 - 2 * Sin(6) = 1.129m 3 = 0.620 • s" = H * Tan(d) + (B * Cos(d) - X) 3 = 2.486 * Tan(6) + (2 * Cos(6) - 1.132) 3 = 0.944m s = s' + s" = 1.129 + 0.944 = 2.07m

Unit Weight of gabion wall, W = A = 1,610 * 3.5 = 5,635 kg/m CHECK FOR STABILITY

l.Overturninq: Overturning moment, Mb = Ph * d = 4,200 * 0.620 = 2,600 kg/m Criteria: Resisting moment, Mr = (W * s') + (Pv * s) = Mk ".F.S. = 5,635 * 1.129 + 665 * 2.07 Mo = 7,740 kg/m

17'= 7,740 = 2.98, which is greater than F.S.= 1.5, and the wall 2,600 will not fail by overturning. 31

CALCULATION SHEET Page 3 of 4

Cross Section of Gabion Retaining 1,b11 - Snook's Arm scale = 1 : 25 drawn : D.G.Skinner 32

CALCULATION SHEET Page 4_of 4_

2.Slidinq: Normal & tangential components of forces acting at base:

N = (W+Pv)Cos(d) + (Ph)Sin(o() T = (Ph)Cos(o() - (W+Pv)Sin(o() = 6,300Cos(6) + 4,200Sin(6) = 4,200Cos(6) - 6,300Sin(6) = 6,700 kg/m = 3,520 kg/m Criteria: u_N F.S. 7r= 6,700 = 1.90 , which is greater than T 3,520 F.S. = 1.5 Therefore, the gabion wall will not fail by sliding. 3.Settlinq Pressure distribution is given by the expression: = N (1+ 6e) where,Cik = pressure distribution 01-2 J B B at the toe of the base = pressure distribution e = eccentricity of the resultant of at the heel of base forces acting at the base

= B - (Mr - Mo) = 2.0 - (7,740 - 2,600) = 0.233 m 2 N 2 6,700 CFI = 6 700*(1+6*0.233) Cc = 6,700*(1-6*0.233) 2 2 2 2 0-1 = 3,350 * (1.699) G. = 3,350 * (0.301) • CC = 5,690 kg/mI Gi= 1,010 kg/m i Since both values for the pressure distribution are less than the load bearing capacity of the soil (10,000 kg/n?), the wall will not fail by excessive settlement. 33 Department of Fisheries and Oceans, Harbours and Infrastructures Branch Grand Fails, Newfoundland

DETAILED COST ESTIMATES Page 1 of 1

Project: Gabion Retaining Wall, Snook's Arm, Newfoundland Estimated By: Douglas G.Skinner Date: 10 July, 1990

Part 1 : Materials

Item* Description Quantity Unit Price Cost

1. Gabions $1,721.44 $1,721.44 2. Coarse Pit Run Gravel 110.0 cubic m. 5.00 550.00 3. Fine Pit Run Gravel 15.0 cubic m. 7.00 105.00 4. 25 mm Crushed Stone 2.0 cubic m. 15.00 30.00 5. Fence Staples 3.0 lbs. 1.50 4.50

Total Estimated Cost (Materials): $2,410.94

Material costs not included: freight charges to ship gabions 6.0 meters of guardrail

Part 2 : Labour & Equipment

Item Description Rate per Hr. No.of hr.

1. Labour $ 8.00 128 $1,024.00 2. Backhoe 50.00 16 800.00 3. Tandem dumptruck 55.00 12 660.00

Total Estimated Cost (Labour & Equip.): $2,484.00

Part 3 : Total Materials $2,410.94 Labour & Equiment : $2,484.00 'Dotal Estimated Cost: $4,894.94 34

SCOPE OF WORK : Gabion Retaining Wall - Snook's Arm

Background

The community of Snook's Arm is one of the chief fishing villages in Green Bay. Last year, a new wharf was constructed in Snook's Arm to provide a landing site for the fishermen. At the request of the Fisherman's Committee, a truck turnaround was constructed to facilitate the manouvering of trucks that arrived to collect the fish catches stored on the wharf. The fish is trucked approximately 18 km. to LaScie for processing. A large portion of the embankment at the truck turnaround collapsed over this past winter and is in need of repair. This project consists of the the refurbishment of that area of the truck turnaround lost due to the failure of the embankment. The slope will be stabilized through the installation of a 16.0 meter long gabion retaining wall.

Contractor's Resposibilities

All parties intending to tender for this work are advised to visit the site in order to make their own estimates of facilities and difficulties attending execution of work, actual site and soil conditions, severity, exposure and uncertainty of weather and all other contingencies.

The work will consist of but will not necessarily be limited to the following:

1. The proper installation of all material supplied by the Department of Fisheries & Oceans, Harbours & Infrastructure Branch, Grand Falls Office.

2. The supply of the proper fill material as specified in the attached drawings.

3. The proper installation of contractor supplied material 35

Quantities

The following material shall be supplied by DFO, H & I Branch:

1. All gabions required to construct the retaining wall according to the plans

2. All guardrails and accessories

3. All fasteners required to attach the gabions to each other as well as to the existing cribwork structure.

4. Approximately 25.0 cubic meters of fractured sandstone rock are required to fill the gabions. This material is anticipated to be readily available on the site. In the event that the supply of this material is not sufficient, then the contractor will be expected to provide the extra material required at a previously agreed price per cubic meter.

The contractor shall be responsible for the supply of the following materials:

1. 110.0 cubic meters of coarse pit run gravel.

2. 15.0 cubic meters of fine pit run gravel.

3. 5.0 cubic meters of crushed stone.

4. All equipment and manpower necessary to adequately perform the work.

Material Specifications:

The materials supplied by the contractor shall conform to the specifications as listed below for each material. 36

1.Coarse Pit Run Gravel shall not exceed 150 mm. maximum particle size and shall be free of any .s4-1-t.

2.Fine Pit Run Gravel shall not exceed 75 mm. maximum particle size and shall also be free of any Silt.

3.Crushed Stone shall not exceed 25 mm. maximum particle size. It shall be clean, hard, and durable.

4.Gabion Filler (Fractured Sandstone) is not to exceed 200 mm. maximum particle size nor less than 75 mm. minimum particle size. The material available at the site will have to be screened or the over and under sized particles will have to be removed by hand from each gabion as it is filled.

Gabion Installation:

Gabions shall be installed in accordance with the phamphlet by Maccaferri of Canada Ltd. entitled "Installation Guide". The gabions that meet at 45 degrees are to be cut so that an overlap is provided at the juncture of these gabions. The overlap will be utilized as surfaces to which the joining wire can be attached to provide a secure bind.

Contractor's Use of Site:

The contractor is advised that the construction operations, including the storage of materials must not interfere with the fishing activity. The contractor will be solely responsible for arranging the storage of materials and equipment on or off the site, and any materials stored at the site which interferes with any of the day to day activities at or near the site shall be removed at the contractor's expense. 37

Contractor's Bids:

A lump sum price to perform the requirements of this project as outlined in the foregoing document and the attached plans, is to be submitted on the form provided and received by Harbours & Infrastructure Branch in the sealed envelope provided, not later than 1600 HRS.(4:00 P.M.), August 20, 1990. Incomplete tenders or tenders received after that time will not be accepted, nor will the lowest or any tender necessarily be accepted. The job is to commence at 0800 HRS.(8:00 A.M.), Monday, August 27, 1990. Prospective bidders are requested to include a unit price (per cubic meter) for the contractor supplied materials in the event that greater quantities of these materials are required beyond the estimated quantities given in this document. 38

Dept.of Fisheries & Oceans Harbours & Infrastructure P.O.Box 459, Grand Falls SAMPLE ONLY Newfoundland, A2A 2J8

Rex. Toms Trucking c/o Mr. Rex Toms LaScie, Nfld. AOK 3M0

RE:Gabion Retaining Wall - Snook's Arm Dear Mr. Toms: You are invited to submit a tender for the above noted project. The following documents are enclosed for your inspection; 1. Scope of Work Document - 4 pages 2. Drawings: GF -0470 -101,Rev.0 - Site Plan GF -0470 -102,Rev.0 - Plan, Section & Elevations 3. Installation Guide: Maccaferri Gabions 4. General Information: Maccaferri Gabions As detailed in the Scope of Work, a lump sum price for this job is to be submitted on the enclosed form and in the envelope provided and received at Harbours & Infrastructure Branch not later that 4:00 PM on Monday, August 20. Incomplete tenders or tenders received after that time will not be accepted. The lowest or any tender will not necessarily be accepted. The contractor is also requested to include unit prices (price/cubic meter) for quantities that may be required extra to those estimated. Work is tentatively scheduled to start at 8:00 AM on Monday, August 27. This is the first opportunity for this Office of DFO to utilize gabions. To this end, we are willing to assist any contractor who is also unfamiliar with gabions to get a full appreciation of what is involved in working with them. Our Engineering Student (Mr. Doug Skinner) will meet with you at some mutually agreeable time to discuss this project. He will bring a small gabion with him for you to examine. Please do not hesitate to call this Office if you have any questions regarding any aspect of this project. Yours Truly,

D.G.Skinner for Andrew Jamieson

A.Jamieson: 292-5177 D.Skinner : 292-5179

39

Price Quotation Form

PROJECT: Gabion Retaining Wail - Snook's Arm

CLOSING DATE: 4:00 PM, Monday, August 20, 1990

hereby submit a lump sum tender of (Company Name)

for Gabion Retaining Wall specified. I/We will begin work on the site within days of notification that we are the successful bidder and will complete the work within days. In addition to the lump sum price tendered above, we can supply and install extra quantities of material that may be required at the

following unit prices; Fine Pit Run Gravel at per cubic meter Coarse Pit Run Gravel at per cubic meter

25 ma Crushed Stone at per cubic• meter Gabion Filler (Fractured Sandstone or equivalent) at per cubic meter

The following equipment will be used to carry out the work:

Signed:

Position: Date: NOTES.

I. ALL DIMENS IO NS ARE IN MILLIM E TE R S. 00 2 . ALL ELEVATIONS ARE IN METERS . EXISTING WHARF ( GO VE RN M E NT OF CA NADA) GU L F OF ST LAW RE NCE

---- ~ " c:? - S I TE c:J

COR N ER , BON" AVI STA BROOK U BAY SNOO K 'S AR M ~ ~~'._/

H E A D

<(, "\. WAT E RS OF SNOOK Is ARM LOCAT I ON P l. AN ,.o' "c \\70 . ~_,, SC AL E I : 5 0, 000 -s- ' '------·------

EL EV 0 003 AT BASE EXIST! NG TREATED 1------, SHORELI N E OF CRIBWORK T IMB E R CRIBWORK WAT ERS OF s OOK Is ARM [STADIA SUR\i t: i RETAI N ING WALL AFT E R DR ED G I N G, GABI ON RE TAIN IN G J ULY ll/9 0 , i\P f0 ROX I -0.0 8 6 1500 HR S. - 0 . 031 ---y ~ 1 - 0.011 I / - E XIS r l NG ARM OUR STONE ~ LL - SNOOK S A.R M --,,,. EMBANKMENT I ii / / / / ~- U. 362 / . . _.,,-\ // ""' ~ ~~~ ~ <.._ TOP OF BA r<: - o.qrnc:_c / ' // ~ 0.482 L __ ~/ "- MATERIAL ST OC KP IL. ::. - '< / -1-'=~04 22/ ~__( '-.(STADIA SURVE Y -J JL · 11190) / ------,.,. 0 1 EXI STING GUAR DRA IL T O w Dr a wing T1t ie -- I BE REMOVED 6 RE-USED ' ' / 1 0 Cf) -.... '·, I I I I I \ ' t] 59 3 -- d5 EXISTING F R ACTURED SA N D STONE ~ -_/ "";;> / I \ TOP OF BA N K lL (STADIA SU RVEY - JUNE 26, 1990) 0:: DEPOSITS TO BE U SED TO FILL THE I ' Ii,- I I \ 4 <( GABI ONS. ?- /f~ I (' S,y 2~2.433 $: LN T SITE PLAN ('D -

w (AFT ER DREDGING) t­ <( > - 0:: "l~ a_

Drawn by SITE PLAN SCALE I : 200 D. G. SKINNER ROCK FACE

Date

JULY , 19 90 B ENCH MARK 2 'x' c ut 1n Anchor Bolt ELEV. = 5 . 293 Scale

200

Drawing No

.__1 ' . ) - J G F - 0 4 7 0 - I 0 I R E v. 'c'

------"--~·~$·~- -~~-~------~--.. -· · • · ·----~-----"------NOTE S

I. AL L DI MEN S ION S ARE IN M I LLI M E T ER S.

END S OF GAB IONS TO BE ATTACHED TO EXI ST I NG CRIBWORK STRUCTURE BY E XI ST ING WHARF ( GOV ERNM ENT OF CAN ADA) 2 . MAT ERI AL E X CAVAT E D DU RIN G CO N ST RUCTIO N I- 1/ 2" GALVAN I Z ED FE NC E STAPLES. (S UPP LI ED BY DFO , H8 I BRA NCH ) EL EV. 2.538 TO B E US E D AS BA C K F IL L ONLY IF A PPR OV ED ELEV . 2. 4 2 1 I BY THE E N GINEER . I J I --< ) ./ . ) - - ' IL - _>I_) -< - ~ - / 1------u,, _, ...., '-- ,. , - --... f I 3. GAB IO NS TO B E IN STAL LE D IN ACCO RDAN CE WITH

T HE MAN UFAC T URER' S INST RUC T IONS .

,______, ._ ,._ _ - ·. r EL EV. 0 .995 ---'- \ ' '- 4 ALL P IT RUN GRAV E L TO BE SUPPLI E D B Y THE

CONTRACT OR .

EL EV. 0. 0 00 EL E V.-0. 2 09 5 . COAR S E PIT RUN GRAV EL S HALL NO T EXC EED ~- - - - - J__ __ _ - J_ _ --- .L -- - l.. -- - .L - -- - 150MM MA X. PA RT I CLE SIZE; F I NE PIT RUN 11000 T YPICAL I GRAVE L S HALL NOT EXCEED 75 MM . MAX .

ELEVATION @ 6. A LL ELE VAT IONS A RE IN METERS . SCA LE - 50 WAT E RS OF WAT ERS OF

SNOO K 'S AR M SN OO K ' S ARM

EL EV 2.421 EXISTING GUARDRAIL TO BE

r------_::':::lI c::======::::::;-~IO~~ ~=~-~--.-+--1---~~~~~;---:--<"-~R~E -~INST--- A L-L E------D AS SHO WN ~ EXIST ING TREA T ED ~ ~ T I M B E R CR I BWOR K I RETAIN I NG WA LL GABIONS T O BE F I L L ED WITH / ------~---"' ~ - ~ FIN . GRAD E IN SI T U FRACT URED SA ND­ IJ...,.... ' J i _ , ( ELEV 2 Pr o jec t T itle ST ONE WITH ANY SI NGLE 8 rC, g · , . I ~00 DIMEN SION NOT TO EXC EE D cJ) (() 2 00MM, NO R TO BE L ES S T HAN 7 5MM . GABION RETAIN IN G . I_,

0 (J. B AC KF ILL WI TH IN SITU EX I ST ING ARMO UR ST ONE PV C CO AT ED GABION S AS MANUFACTURED BY I~o 0 BOUL DERS Bl GR AVE L PR OT ECT ED EMB ANK MENT WALL- SNOOK'S ARM 0 MACCAFERRI OF CANA DA. ~ OVER L ADEN WITH CO AR SE SUPPL\ ED BY DFO, H 811 { PIT RUN GRAVEL 81 TOPPE D BRA NCH. ELE V . WITH 150MM MI NI MUM OF 0.9 9 5

"CJ (lJ .c Drawing Ti tle {j)

0 .c :;: 2' 0 > L N T PLAN, SECTION, 8 a..

E X ISTING SLOP E ELEVATIONS

S LOPE 3 ·.I MA X. SECTION x-x / SCALE - I·. 2 5 Drown by

D. G. SKINNER E L EV. 2.421 - . \ I. '-' ' ' ' - \..._ \. ';.... ~ _r Do te " ' ...., '4- \. .' ' ' \ -\ ' ' \. .. - \ _ \. \..._ \ ...... ' -, ' ' "\, ~. ·, '- \.... \"-<• \ ~ -- ,..... }..... ~ ... ) ' ·-.. -, \ "'\ r--.., ...... \- o ce _,______) . - \ . '· \ "\ ·- ...... '-, '> < ::: r \'< OC ~ \.-... ·· · \. . ,.-. . JULY,19 9 0 ' "'\ ~ ~ - - ~< , . E L EV. 0. 995 ~BEN C H M ARK 2 ' X' c ul in A nch or B o lt ELEV= 5 .293 Sca le ./

ELE V. 0.000 ELEV . - 0.209 ---~- - - ~ ---~ - -- ~ - - -~--- ~ ---~ -- - L - - - SHO WN

1000 TYPICAL ELEVAT IO _ Dra wing No SCAL E 50 ® P L . N SC A LE- 2 0 0 G F - 0 4 7 0 - I 0 2 RE v. 'c'

------~------...._ ____,,_ __ ~-· " ' ~~,.~------~~· -~ ·n=~~ ,~· - ~'""'______..... ______