Some people view the presence of logs and brush along the roadside as being aesthetically offensive. If not properly anchored and embedded in the slope, the brush material may be ineffective and could come loose to block ditches or culverts. Studies have shown that a track-mounted Caterpillar backhoe was able to construct windrows at a rate of 52 metres per hour feet per hour from Cook and King.
This figure does not count the cost savings in not having to dispose of the brush in push-outs. Silt fences are installed to collect sediment from small areas during construction. Typically, they would be built at the toe of an embankment slope, along the bank of a sensitive stream, or at the downstream end of an erodible earth cut area.
The maximum slope length behind the barrier should be no more than 30 metres feet , and it should be no steeper than 2 : 1. Silt fences act like a strainer; silt and sand are trapped on the surface of the fence while water passes through.
Silt fences also reduce the velocity of sheet flow and thereby induce the deposition of sediment. Silt fences are relatively inexpensive filtering devices in the form of permeable or semi-permeable fences or dams. They may consist of woven geotextile filter fabric or straw bales placed in the path of flowing water. Silt fences are flimsy, lightweight structures suitable for filtering small volumes of water flow, therefore their use is limited to small drainage areas. They should not be placed across a drainage path that carries high-volume or high velocity flow where washout could occur.
Failure of a silt fence due to improper installation may allow a considerable quantity of accumulated sediment to pass down-stream. Straw bales are difficult to obtain in many areas where access roads are constructed and they only last from three to six months. A silt fence, 10 metres 30 feet in length, may require four wood posts and about 20 square meters square feet of geotextile fabric.
The forest floor adjacent to the right-of-way provides a natural sediment filter at virtually any location on the downstream side of the road. Use of this natural filter is particularly important near water crossings, so that turbid runoff does not flow down the ditch and stream banks into the water directly.
The natural forest floor, with its litter and vegetative material, can be used to serve as a filter medium to trap sediment before it reaches a water course.
This treatment may require construction of an earth diversion berm across the ditch line, and excavation of a channel to carry water to the edge of the right-of-way.
A diversion berm is different from a check dam because water is diverted out of the ditch and not allowed to flow over the berm. Berms should have a top width and height of at least millimetres 20 inches and side slopes of 2 : 1 or flatter. Since the diversion berm will be redirecting flowing water, the upstream surface should be resistant to erosion from the expected flow velocities.
The recommended spacing between ditch outlets depends on the slope of the ditch and the erodibility of the soil; refer to Table 1 in Section 5. Ditch channel, berm size and outlet channel must be of adequate size to handle expected flow, including flood flows. If not properly sized, the berm will overtop and flow will continue down the ditch line.
A nominal cost may be incurred to construct the berms and provide off-take channels, however this would be offset by a savings in downstream ditch size and elimination of the possible need for erosion protection. Road culverts are ideal sites for beavers to construct dams for backing up water and creating habitat. Blockage of culverts by direct beaver activity, and the failure of beaver dams that cause the sudden release of water, have led to many road washouts.
There are two types of action that may be taken to minimize the problem:. In new construction taking place in beaver areas, the use of larger culvert pipe diameters will tend to make dam construction more difficult.
Battery operated electric wire fences, such as those used for farm animals, have also been successful in discouraging beaver activity by giving them an electrical shock at the culvert inlet. Devices can be installed upstream of the culvert inlet to prevent dam construction in the pipe itself. Bed springs have been used for years as a screen. More sophisticated attachments include a wire mesh culvert protector that is a three metre 10 foot upstream extension of the culvert, made of heavy wire mesh rolled to the diameter of the culvert.
Patented culvert attachments are also available from several suppliers. These devices attract the beaver to build in a certain location where periodic removal of debris is not as difficult as from inside a pipe. Some of the attachments must be removed to ensure free flow of water during flood periods.
As long as the beaver is active in the area of the culvert, maintenance will be required. If the above methods are unsatisfactory or undesirable, it is recommended that, through the Ministry, the services of the local licensed trapper be enlisted to remove the beavers or to keep the culvert area clear. Beaver, as fur bearers, are protected under legislation; their removal is subject to factors such as seasons, quotas and license requirements involving trappers.
If beavers are trapped outside of peak season, the fur quality and its value will be reduced; thus, some compensation may have to be paid to the trapper. Removal of beavers and breaching of beaver dams often proves to be a temporary solution since other beavers in the area may move in and take over if the habitat is favourable.
Good water crossing construction practices should protect fish spawning areas. However, if erosion and sediment control measures have not prevented silt from damaging spawning beds, then the rehabilitation of fish habitat may be required.
This may require restoration of a degraded spawning area to a condition that sustains the incubation of fish eggs. In other cases, spawning areas may be affected by the physical presence of a water crossing, and thus some habitat development may be required.
This may involve the creation of new spawning beds in areas where they did not previously exist. Sometimes, if spawning areas are limited, the construction of a water crossing may provide the opportunity to create additional spawning areas. There are two main techniques used to rehabilitate and develop spawning areas.
One technique is to clean spawning gravels with high pressure fire hoses, beginning at the upstream end and working downstream, pushing silt and dead algae ahead of the water discharge. The other technique is to add suitably sized rock to create spawning areas using the following guidelines:. The use of bridges or arch culverts is recommended for fish migration routes where the roughness of a natural stream bed is desirable for reducing flow velocity.
In some cases, the same effect can be achieved in pipe culverts by installing a layer of stone, provided the stones are large enough not to be moved by the design flood.
Larger rocks, one to ten metres three to thirty feet apart, can provide resting places for fish, providing the rocks are alternated from side to side to prevent long runs of fast water along the side. The greater roughness of corrugated interiors may be an advantage for fish passage, and for other situations where barrel or outlet velocities must be reduced.
Bolt connections should be installed with the bolt head on the culvert interior to prevent fish being damaged on the sharp nut and bolt end. Culverts on fish migration routes should not unduly hinder the passage of fish during flow conditions likely to prevail at the time of migration.
The corresponding discharge, of or fish passage design flow, is applied to the culvert after it has been sized to satisfy the normal flood flow criterion. If migration and the annual flood period are likely to coincide, as for spring spawners such as walleye and suckers, the simplest approach to determine of is to use mean monthly flow estimates for the May-June period.
This allows for the fact that fish normally wait for a day or two after the flood peak has passed. If an average flow depth at the time of migration can be established, Qf may be calculated by multiplying the average flow depth d by the average width B and the estimated average velocity V in the stream cross-section, i.
It is recommended that fish should not be delayed longer than three days on the way to their spawning grounds, but this depends on where the culvert is located on the migration route. Not all fish have equal swimming ability.
Figure A indicates that trout can handle higher velocities than pike. Swimming ability is also based on fish size. Normally larger fish can handle higher velocities better than smaller ones, but smaller fish may be able to use the zones of lower velocity water near the bottom or sides in culverts; this factor may obscure the relationship between swimming ability and fish length.
The graph shown as Figure A may be applied to culverts using the mean water velocity at the fish passage design flow Qf and the culvert length as the swimming distance. Slope is the most important factor determining water velocities in culverts at lower flows. Keeping the culvert gradients as flat as possible will encourage fish migration. If the fish velocity criterion cannot be met by modifying the culvert design, baffles, which create resting areas at intervals along the culvert, can enable fish to pass through.
In the construction of highways and streets in Ontario, aesthetics represent an important consideration. These roads are part of the environment in which people live; many spend a measurable proportion of their time travelling on them.
Aesthetics, or the appearance of a roadside environment, is a personal subjective matter. Traffic volumes on the highway system are relatively high when compared to access roads in the bush.
Average traffic on an access road constructed for timber management activities might reach 50 vehicles per day during the most active harvesting period, and drop to perhaps five vehicles per day after harvesting. For this reason, the benefits of improved aesthetics on access roads do not usually justify the high cost of landscaping the roadside environment to make it pleasing to the eye.
Current practice is to identify, during the road planning phase, those roads and work areas that should be constructed to a higher aesthetic standard of appearance than is considered necessary to protect the physical environment.
For example, a major access corridor that will carry long-term, multiple-use traffic could be identified as requiring special attention for aesthetics.
Action required to improve the appearance of a road must be measured against other factors, such as a greater impact on the physical environment, increased construction costs, or a reduction in safety for road users. This practice is economical and environmentally sound.
Most people would prefer to look at a roadside where grubbing material is placed in push-outs, although this practice removes organic material from the right-of-way, exposes soil to erosion and takes in a larger surface area for road construction activities.
Another example would be the intentional placement of curves on the approach to a single lane bridge to limit view of the road from the river.
Although providing aesthetic benefits, the action will reduce safety for drivers and pedestrians. As these examples illustrate, the guidelines for aesthetics should not be implemented unless there is an identified need. As part of the decision-making process, the additional cost of taking special measures for aesthetics should be determined and weighed against the benefit. Additional information on designing for aesthetic values may be found in the Ministry publication, Timber Management Guidelines for the Protection of Tourism Values.
Evaluation of the swimming performance of several fish species from the MacKenzie River, D. Jones, J. Katopodis, P. Robinson and B. Liard Highway Hydrology Study, M. Dillon Ltd. Rothwell, The Forestry Chronicle, April Rajaratnam, S. Lodewyk and C. Cook and J. Experiment Station, Ogen Utah, U. Department of Agriculture, U. Forest Service, Belford, M. To have a better experience, you need to: Go to your browser's settings Enable JavaScript.
Home Environment and energy. Environmental guidelines for access roads and water crossings Direction on the construction and maintenance of access roads and water crossings in a forest environment. On this page Skip this page navigation. These include: aquatic water quality and fisheries terrestrial plants and animals recreation, cottaging and tourism historical and archaeological aesthetics at some locations air quality dust abatement, pollution control noise levels worker and public safety economic considerations The purpose of this manual is to establish standards and provide practical advice for ensuring minimum disturbance to the natural environment aquatic, terrestrial.
The specific objectives of this manual are: To provide up to date environmental guidelines appropriate for the construction, maintenance and abandonment of access roads and water crossings. To establish mandatory standards to be followed when constructing, maintaining and abandoning access roads and water crossings on Crown land to ensure a minimum level of environmental protection.
To record and disseminate information about good practices being used in Ontario which have proven effective in minimizing the impact on the environment. To provide design information about special mitigation techniques that may be used to eliminate or reduce potential negative environmental impacts. It may be useful to readers who wish further details on specific areas of interest. The guidelines contained in this manual apply to all types of access roads, including this tertiary road.
Construction of a water crossing Any activity on Crown land during the forest fire season. Construction near a water body that could have a detrimental effect on fish habitat or water quality. Development and operation of a borrow pit or gravel pit.
Any activity associated with timber management on Crown land. All applicable legislation, as identified in Section 3, must be complied with. Those persons responsible for construction must ensure the necessary approvals and permits are in place before physical site work begins.
Conditions of those approvals and permits must be met. A use management strategy for each primary and secondary road or for each timber management unit must be developed; this is to include consideration of other uses and abandonment when the road is no longer needed for its original purpose.
Areas of concern identified during the planning process must be adequately addressed. Areas of concern include locations where particular values are to be protected and environmentally sensitive areas which require special attention.
Appropriate mitigation techniques must be followed throughout the planning, design, construction, maintenance and abandonment of the road. Other uses of Crown land identified in advance e. Preservation and restoration of vegetation is necessary to protect water quality.
To avoid delays, this review should occur well ahead of the proposed road construction. During the construction and maintenance of access roads and water crossings, appropriate measures must be taken to prevent contamination of water bodies by foreign materials such as lumber, nails, logs, brush, fuel, oil, lime, cement, asphalt, calcium chloride, sodium chloride, oil base wood preservatives and herbicides.
No herbicides are to be sprayed within 10 metres of a water crossing. Clearing operations in rights-of-way must conform with the requirements of the Crown Timber Act , including the harvesting and utilization of salvageable wood. Materials moved during construction, such as grubbing, earth fills and earth cut materials must not be piled where they block drainage courses. The use of heavy construction machinery on streambeds is not permitted during spawning and incubation periods and must be kept to an absolute minimum at other times.
Waterways must not be blocked so as to impede the free movement of water and fish. Clearing and grubbing of low vegetative cover within m feet of a water crossing, or other water body identified as being sensitive by the Ministry, must be kept to the absolute minimum necessary for constructing the project.
Exposed mineral soil within metres feet of a water body must be graded to a stable angle of repose to prevent erosion. Access routes to lakes and streams outside the road right-of-way limits must not be constructed without the approval of the Ministry.
Permanent diversion or channelization of an existing water course is generally inadvisable and, if undertaken, must not create any more disturbance of the natural environment than absolutely necessary.
Waterway size and erosion resistance of the new channel must be comparable to those of the natural channel unless a special engineering analysis and design justifies an alternative approach. The new channel must be constructed in the dry to the maximum extent possible.
Fill material placed below high water level within the floodplain of water bodies must be erosion resistant. Construction techniques used at water crossings must be selected to protect water quality. This may require the selection and use of special mitigation techniques.
Fill slopes and waterway banks disturbed during construction must be trimmed to a stable angle of repose. Upon completion of a water crossing, any temporary fill, culverts, refuse, etc. Staff, as part of their normal field duties are expected to observe, on an annual basis, the condition of water crossings on maintained roads, particularly with respect to the potential for washouts or blockages of culverts.
Problems are to be reported to the appropriate road authority. Naturally abandoned roads will be inspected at least once every three years and more frequently where circumstances, such as abnormal rainfall, warrant. When a road is physically abandoned footnote 1 [1] appropriate measures are to be taken to prevent significant erosion and sedimentation of water bodies.
These measures may include the removal of culverts and bridges and grading of slopes to stable angles of repose. Inadequate opening size can lead to washout during floods.
Washed out culvert was replaced with new arched culvert having sufficient opening. The seriousness of the impact depends on many factors, including: type of natural environment terrain difficulty soil types along the route construction materials used geometric road standard construction and maintenance practices a mitigation techniques implemented road abandonment practices The good practices described in this section apply to all types of roads.
Using this sequence, the good practices have been grouped into the following components: road planning and location a clearing grubbing earth grading a rock grading drainage ditches and culverts swamp treatments graveling road maintenance road abandonment 5. Good practices - location: Ensure areas of concern in the planning stage have been identified and dealt with.
This may require special mitigation techniques such as protection of canoe routes, erosion control at water crossings, building neat push-outs for aesthetics, avoidance of osprey nests. Select the location of water crossings well in advance of construction, particularly those identified in Timber Management Plans.
Avoid unfavourable construction areas as much as possible. For environmental as well as practical considerations, road alignments should follow the contours of the land. Long, sustained grades should be avoided since they allow excessive runoff buildup in ditches and can lead to erosion.
Keep roads away from recreational areas, water bodies and wetlands, except where water access or aesthetic viewing is an objective of the road. Buffer zones of undisturbed vegetation between access roads and water bodies should be maintained and should increase in width proportionally to the increase in slope of land entering the waterway.
Minimize the number of water crossings. Geometric road standard should be appropriate for the intended use and for the duration of use of the road. Construction to a higher standard than necessary increases costs and has the potential for more environmental damage.
Identify sources of material for road construction, and consider locating the road near these sources, in order to minimize haul distances and provide better materials to work with. Landings, loading areas and turnarounds should be located when the road is being laid out. Landings should be on high ground to avoid rutting and blocking of drainage paths. Higher standard roads cost more money and result in greater environmental change.
Good practices - clearing Do not clear an area larger than necessary to meet the geometric standard for the road; control clearing width using marked sidelines. Reduce clearing width to the minimum needed for construction within metres feet of a water crossing, or a water body identified by the Ministry as being sensitive. Away from water crossings, a minimum width of 20 metres 66 feet should be cleared to ensure the road will dry out, and to provide sight lines for safety.
Trees should be felled away from standing bush and water bodies. Push-outs should be pre-cut. Locate them on the low side of the road, but without blocking drainage.
Landings should be pre-cut, on high ground, off the right-of-way, and in scrub brush areas if possible. Salvage merchantable timber from right-of-way clearing. Clear in winter months to reduce rutting. Slash debris should be disposed of as part of the grubbing operation. Grubbing is done to expose the mineral soil for three reasons: To prepare for earth grading operations.
To improve roadway performance by eliminating weak organic material in the zone carrying wheel loads; and To minimize future sight distance problems that roadside vegetation could cause.
Good practices - grubbing: To ensure that trees on the bush line are not under-cut, a cleared but not grubbed buffer should be left along the edge of the right-of-way. Grubbing should not proceed too far ahead of construction. This will limit the time that the mineral soil is exposed to erosion. Grubbing material should not be piled where it will block drainage courses.
If windrows are used, they should be kept behind roadside ditches and breaks should be provided so animals can move across the right-of-way, say 5 metres every 65 metres 16 feet every feet. If push-outs are used, they should be pre-cut to a large enough size to avoid knockdown of standing trees.
Swamps should not be grubbed. The stumps in swamp areas should be shear bladed in winter if possible. If some organic material is left in place, it will make nutrients available to ensure rapid re-vegetation of the right-of-way. This can be done by using special blades or attachments on a bulldozer and by grubbing in winter when the blade can ride on the frost. In areas of fine grained soils clays, silts and fine sands which are subject to erosion, the area to be grubbed should be minimized.
Grubbing in fine grained soil should be avoided during wet weather. This will prevent severe rutting and unnecessary disturbance of the clay or silt soil. Postpone the grubbing operation until drier conditions prevail, or close-cut the trees and do not grub. Good practices - earth grading: Soil instability due to soft clay, springs or erosion can result in road failure.
Treat soil instability by reducing the loading fill height or with counterbalancing side berms. Treat persistent springs with sub-surface drainage. Where there are potential serious consequences of soil instability or erosion, erosion control techniques should be used promptly.
Retain natural vegetation near water crossings as long as possible, to reduce the time that the soil is exposed; i. Do not dump waste material in areas that may block the flow of water. Fill in or around water bodies should be constructed with earth-free rock or clean, well-graded, granular material; this will help reduce the impact on fish habitat and water quality.
Install drainage culverts as part of the earth grading operation. Excavate cuts uphill to improve drainage and make material more workable. Complete ditches as cuts are being excavated.
Keep earth fills and earth cuts as shallow as possible, consistent with the geometric standard being constructed. A road surface about one metre three feet above the original ground should be satisfactory for most roads, if the terrain is favourable. Grade and crown the earth grade as it is being constructed, to shed water and minimize ponding in ruts. Fills should be constructed in shallow, full width layers with stable side slopes to 2. Equipment should be made to travel the full width of each layer to compact it and make the fill more dense.
This will minimize slope erosion and soft shoulders. When building fills on side slopes, benching into the original ground will prevent slippage along the interface. When borrow from outside the right-of-way must be trucked in, try to obtain granular material. It makes a strong roadbed, drains well, is easy to compact, and is erosion-resistant. Limit the number of pits to minimize the area of disturbance. When obtaining material by excavation within or adjacent to the right-of-way, try to drain low pockets.
This may not be necessary when standing water does not create any problems, e. Maintain adequate control over grading operations to ensure the road is not over-built or under-built.
This usually requires some survey layout, staking limits of cuts and fills, and supervision by a grading foreman. When working with wet, fine-grained soils clays, silts , it may be necessary to push the material up and leave it to dry for some time.
When dry, such otherwise unsuitable materials can make an acceptable roadbed. Use of the backhoe for this operation may speed the drying time and reduce damage to the original ground. Fill construction in shallow, full-width layers ensures a stable road bed. Benching will help stabilize slopes when constructing fills on steep side hills.
Good practices - rock grading: Plan rock fracture to produce usable size particles for rip rap and other needs on the construction project. Plan drilling patterns and limit explosive loadings to an appropriate level that will shatter the rock and heap it up vertically, but will not throw the material into the bush.
This will limit damage outside the right-of-way and make the material available for fill or other uses. Where bedrock projects into the ditch line of a roadside ditch, construct an off take ditch into the bush, install a cross culvert, or excavate through the rock knob.
Good practices - culverts: Use permanent materials on permanent roads e. If the road is temporary, culverts and fill deposited in the floodplain should be removed when no longer required. Installation should be done in driest possible time of the year.
Installation should be carried out ahead of fill construction or as part of it. A high culvert will cause ponding upstream and outlet erosion downstream. Too low a culvert will fill with sediment and may freeze over in the winter. A single larger pipe may be preferable to several smaller ones, because it should be less susceptible to blockage or icing.
In swamps, culverts should be placed where the organic depth is least to minimize settlement. Where cross-culverts are used on down grades to divert flow and minimize ditch erosion, they should be angled across the road so water will flow easily. When foundation conditions are such that a sagging of the central portion of the culvert is anticipated, the central portion should be installed with an upward camber. Anticipated sag will then tend to restore the culvert to a constant gradient. Culvert length should be selected to ensure ends will not be blocked by fill slopes.
The minimum culvert size used on roads needed for more than ten years should be millimetres 18 inches in diameter. Rip rap should be placed on the upstream fill slope around the culvert inlet, to the top of the pipe, to prevent fill washout during high flow periods. If scour of the streambed downstream of the culvert is expected due to the high flow velocities, an erosion resistant apron or energy dissipater should be provided. Good practices - ditches: Ditching should be carried out as part of earth grading, to encourage good drainage early and to minimize soil disturbance.
Ditches should be constructed uphill, to avoid trapping rainwater. All roadside ditches should flow to an outlet downstream of the road right-of-way.
Ditches should be sized to handle the expected runoff from the area draining onto them. Large drainage areas may require deeper or wider ditches than are normally provided. On all-weather roads, ditches should ensure that the water level is maintained at least one metre three feet below the road surface. Cross culverts and off take ditches are required to ensure adequate road-side drainage. The recommended spacing of these depends on ground slope and soil type, as indicated in Table 1.
Roadside ditches should not discharge directly into waterways; rather, off take ditches should divert flow into the bush so the water filters through natural vegetation before entering the waterway. Construction of diversion berms in the ditch-line may form part of the off take ditch scheme; refer to the appropriate guidelines in Section 7. Interceptor ditches may be necessary to divert water away from steep cut or fill slopes. To ensure that drainage ditches are not blocked, side roads should be located on high ground, or entrance culverts should be installed.
Side slopes of the fill and cut back-slopes should be flat enough to be stable in the long term, so that slumping and filling of the ditch does not occur. Ditching is carried out as part of earth grading, to encourage good drainage early and to minimize soil disturbance. In constructing roads over swamp areas, there are two main considerations: Do not exceed the load-carrying capacity of the soft material; and Provide adequate cross drainage.
Good practices - swamp treatments: Deep swamps should be avoided if at all possible, due to the risk of failure and the potential cost of repair. Select a crossing location where there is a well-developed root mat supporting tree growth. Construction of swamp treatments in the winter has several advantages: it permits shear balding of stumps; heavier construction equipment can cross without getting bogged down or disturbing the root mat; and, construction can also proceed beyond the swamp without having to wait for the treatment to be completed.
The most common swamp treatment method on access roads is to float the road fill on the natural root mat and minimize disturbance of the organic deposit. This is economical and, of the methods available, causes the least disturbance to the natural environment. If possible, limit fill depths over the swamp to 1. When fill heights swamp loadings cannot be limited to shallow depths, the swamp should be sounded with a steel rod to a solid bottom, so that future performance can be predicted.
The root rant under the roadway should be protected from equipment damage. This can be done by: diverting through traffic to the edge of the right-of-way; close cutting or shear blading stumps instead of grubbing; and, using special wide-pad equipment.
Avoid ditching in deep swamps unless absolutely necessary say over one metre thick three feet. If the consequences of the natural mat failing are serious, use reinforcement materials such as geotextile fabric, geo-grid mats, brush mats or log corduroy.
Fill used on swamp crossings, where the road is floated on the natural mat, should be free from large boulders or rocks that can puncture the mat. Provide frequent cross culverts, approximately every metres feet , to ensure that surface water is equalized on both sides of the road. The culverts should be located where organic deposit thickness is least thus less settlement.
If culverts must be placed on top of deep organic material, it is best to leave their installation until late in the road construction, after some settlement has already occurred. Elements of a Swamp Treatment, cross-section showing floating the road 5. The operation generally involves importing select material from a gravel pit nearby. Good practices - graveling For the top millimetres six inches , a well-graded gravel with particle sizes evenly distributed between clay size and 25 millimetre one inch stones is preferred.
It can be easily placed and compacted to the desired shape and will be more stable under load than a poorer quality material. Where no value for U is specified in Table These guidelines may also be used, with Approval, for existing roadways where operational issues such as collisions, traffic delays, etc. It has become apparent, however, that for bridges with low traffic volumes these requirements have become too stringent.
In order to achieve economies by the relaxing of requirements, and without compromising safety, a task force with MTO Regional and Head Office participation was set up to develop guidelines for this purpose. As a result, this section has been formulated. Where applicable, the CHBDC Clause number that is being modified is provided, along with the reference to justify the provision.
A commentary is also provided. Application of these recommendations to bridges on low volume roads will provide an opportunity for savings on structures in these situations. Resource Access Road A road used for mining, forestry and energy development. Local Road A road primarily used for land access. Collector Road A road providing for land access and traffic circulation. Arterial Road A road primarily used for high volumes of through traffic.
The level of performance is less than that for LVPL2 and is intended for very low volume and low speed traffic. Alternate load paths may be desirable due to the lack of maintenance that is common on low volume roads Cl.
Approach slabs may be beneficial for high abutments to reduce the effects of live load surcharge Cl. Commentary For these roads, the growth would generally be small. These roads are generally lower service roads and settlement would not be a great inconvenience compared to other hazards on road. Material condition and physical properties should be determined prior to their use Cl.
Shorter bridges and bridges with catch basins at the ends of the structure often do not require deck drains. Where existing roadway alignments have proven to perform well, then the existing alignment can be used Cl.
Adequate warning should be given to traffic in the case of narrow or single-lane bridges. Certain cases may require a lower life. Consideration should be given to a lower life cycle where alignments are substandard, but improvements are cost prohibitive.
In those situations, the owner may not be able to correct the alignments, but also may not wish to be committed to the substandard alignment for 75 years. Cost savings from used material may be significant. Traditionally, bridges generally had more drains than required. This allows structure replacement at same location if old structure was adequate.
Reduced widths result in lower costs. With AADT less than , the probability of 2 vehicles meeting on the bridge is low. If there are sight distance issues, a single lane bridge should not be used. Consultation shall be made with local officials. It may also be acceptable to have a lower barrier to accommodate these farm or other special vehicles. The return period should be determined by the Owner to establish an acceptable length of time the structure is impassable.
Larger risk of overtopping is tolerated. Slightly smaller stones are acceptable. Relief flow may be difficult to accommodate. Higher risk of flooding is tolerated, especially if alternate routes are available or if use during flooding is lower. High vulnerability bridges include log bridges, bridges with timber beams and deck, and light trusses. Low Vulnerability is defined as a bridge that will not experience significant damage during flooding.
Low vulnerability bridges include rigid frames, integral abutment bridges, and slab or voided slab bridges. The live load surcharge can be proportionately decreased with the decrease in truck load Cl. Emergency and maintenance vehicle weights should be considered when determining the appropriate design loading. Only 1 truck will be present in the lane. If properly posted and for specific uses, a lower load limit bridge may be adequate.
A reduced passenger comfort is allowed. This lowers initial and maintenance costs. Other joints can perform adequately for smaller movements.
The lower performance barriers can be used on lower speed, low height bridges. These have been used for low volume roads in the United States. The reduced slab thickness can be used provided that the constructability can be ensured Ref.
The magnitude of the mm surcharge load is calibrated for the full design truck. Where an existing bridge has performed well and where no grade revisions are expected, or where the structure is designed to accommodate settlement, no Foundation investigation is required.
Weaker concrete is too permeable. Stricter rebar tolerance may be required for thinner decks. With low traffic volumes, the wear will be minimal. These are all durability related Clauses that will not apply if salt is not used. Stressing closes the gap between laminates, minimizing ingress of water. Geometric Design Standards for Ontario Highways. Otte, V. Wyle, and A. Gangarao, M. Ronald K. Faller, Barry T.
Rosson, Dean L. Strands, and P. Tendon Ducts Technical revisions and additions to the Procedures Division are indicated by the date shown in the left portion of the header title block.
When additions or revisions are necessary, they will be made available through Publications Ontario or the MTO Research Library online website, as detailed in Section 1. Ministry: means Ministry of Transportation, Ontario.
Standard drawings for attachment on or insertion into contract drawings in the manner specified in 2. Standard drawings for use as contract drawings.
New standard drawings being issued in category a are generally in x mm format. For the purpose of this Introduction, standards in this category are referred to as "small size" standards. Standard drawings in category b are issued in the structural contract drawing format.
They contain two title blocks that must be completed by the user. For the purpose of this Introduction, standards in this category are referred to as "full size" standards.
In this Manual, reduced scale copies of the full size standard drawings have been assembled in a separate category following the small size standards. Procedures have no prefix. Except for full-size standard drawings see later , the one or two digit number after the prefix, if there is a prefix, is the Section number. All Divisions use the same subject-oriented Section numbering system. The same principle applies to Design Aids. The Standard drawing sheet numbers in the system are not completely sequential.
This is to permit the addition of future sheets in the appropriate place without disrupting the numbering system. In order to distinguish between the full size standard drawings and the small size drawings, the full size standard section numbers have been increased by The next two digits 16 show that the drawing belongs to Section 16 Miscellaneous. The job-specific information should be added at the time the standards are included in or attached to the drawings. If details and notes as shown on SS standards are not applicable, they must be deleted, crossed through, or labelled "Not Applicable".
Where information in tables and dimensions are added to a standard drawing for its completion, the drawing shall bear the seal, date and signature of an Engineer. This Engineer accepts full responsibility for the accuracy of the added information only. This Engineer accepts full responsibility for the modifications to the drawing only. Where changes are made on a standard drawing that affect the original structural design, the drawing shall be identified as "Modified" and bear the seals, dates and signatures of two Engineers.
These Engineers accept full responsibility for the design that results from the changes. They are suitable for use by all owners and reflect a consensus of opinion about acceptable practices to ensure the owner's requirements for quality and the contractor's need for efficiency are satisfied. The Ontario Provincial Standard Drawings are provincial publications and are not automatically used by the Ministry.
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