E_div 4 Urban Roads Characteristic

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DIVISION 4 URBAN ROADS CHARACTERISTIC 45

4.1 Introduction 45

4.2 Urban Roads Classification 45

4.2.1 Local Roads 45

4.2.2 Collector Roads 46

4.2.3 Arterial Roads 46

4.2.4 Highways (Freeways) 47

4.2.5 Industrial Roads 47

4.3 Pavement Thickness 47

4.3.1 General 47

4.3.2 Pavement Thickness According To Urban Roads Classification 48

4.4 Correlation of Pavement Layers With Non-Pavement Road

Structures 48

4.5 Environmental Principles For Urban Roads Construction 49

4.5.1 Noise 50

4.5.2 Vibration 50

4.5.3 Air Pollution 50

4.5.4 Material Extraction and Disposal Sites 50

4.5.5 Hazardous and Dangerous Materials 51

4.6 Traffic Control During Construction 51

4.6.1 General 51

4.6.2 Traffic Control Procedures 51

4.7 Work Site Protection 52

4.8 Maintaining Or Transferring Utility Lines 52

4.9 Common Transport Stops 53

4.9.1 General 53

4.9.2 Construction Requirements 53

4.10 Protection of Adjacent Streets From Wastes And Contamination 54

4.11 Drainage Works For Urban Roads 54

4.11.1 Surface Drainage 54

4.11.2 Underground Water Drainage 54

4.11.3 Drainage Requirements For Trees And Plants Irrigation Water 55

4.11.4 Sewage Water Drainage 55

4.11.5 Water Draining During Construction 56

4.12 Traffic Safety Requirements On Urban Roads 56

4.12.1 Sidewalks 56

4.12.2 Pedestrian Crosswalks 56

4.12.3 Safety Barriers 57

4.12.4 Informatory Signboards And Panels For Pedestrians And Cars 57

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General Specifications of Urban Roads Construction Division 4- Urban Roads Characteristics

Ministry of Municipal & Rural Affairs – Kingdom of Saudi Arabia 45

DIVISION 4

URBAN ROADS CHARACTERISTIC

4.1 Introduction:

Road network is a major factor, which reflects the economic development ofcountries. They provide the capability to move and travel from one place to another and

the roads development is reflected on different aspects of economical and social life.

Urban roads are different from rural highways by a group of characteristics, which

affect their design and construction conditions. These characteristics are:

- Considerable volume for passenger cars of low axial loads (ESALs).

- More number of road intersections.

-

Small areas designated for construction.

- Passing of those roads through residential areas, which impose a group of executive

and environmental conditions.

This division contains the most important factor that characterizes urban roadsand which may be reflected in the specifications of urban roads construction, and

includes:

- Urban roads classification.

- Pavement layer thickness.

- Correlation (Relationship) between pavement layers with non-paving

elements.

- Environmental principles for constructing urban roads.

- Traffic control during construction.

- Work site protection.

- Maintaining or transferring public utilities.

-

Common Transport Stops.

- Protection of adjacent roads from wastes and pollution.

- Drainage works on urban roads.

- Pedestrian and vehicles safety requirements.

4.2 Urban Roads Classification:

The classification of roads in these general specifications is aimed at describing

the specific characteristics of each category and to facilitate the link between the

specific requirements of materials and works, which shall be indicated later in different

divisions of these specifications for each category.

Urban Roads classification in these specifications is based on the classification

included in the Geometric Design Manual for Roads issued by the Ministry of

Municipal and Rural Affairs which complies with the S.A Ministry of Transport and

international organizations Methodology such as AASHTO which classify roads

according to their function in the network.

Roads shall be classified into the following classes:

4.2.1 Local roads:

The function of local roads is to provide approach to housing entrances,

buildings and adjacent property and they are mostly used for traffic generated from orends at the same area from which traffic moves directly to adjacent roads.

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These roads may service residential or residential commercial areas and in the

latter case the volume of traffic is higher. However these roads can be multi lanes but

rarely contain medians.

Traffic volume in these roads does not exceed 3000 cars per day and it

composed mainly of passenger cars, waste collection trucks and constructionequipments, and generally not utilized by buses.

In industrial areas it is possible that percent of heavy vehicles is predominately

more and the axial loads at these areas are higher despite of their low traffic volume.

Local roads are connected with other local roads and collectors and may directly

connect with arterials in some industrial and commercial areas.

Traffic access on these roads is unrestricted and traffic control means are simple,

composed of stop signs or Traffic signals.

4.2.2 Collector Roads:

The function of collectors is to provide connection between local and arterial

roads and normally direct access to adjacent areas is allowed. Traffic volume in

collectors varies from 1000-12000 vehicles per day and it might have more than two

lanes and divided by medians.

Traffic flow in commercial and industrial areas is mixed and include passenger

cars and trucks moving from or to arterial roads, however, in residential areas passenger

cars are the predominate and heavy vehicles are only the service vehicles.

The movement on collectors in commercial centers and adjacent areas is

interrupted due to traffic signals but at residential areas the traffic control means are

simpler.

There are some restrictions for parking at peak hours and there are no

restrictions for pedestrian crossing but it is preferable to designate specific places for

crosswalks in the parts having high traffic volume.

Sometimes it is preferred to construct special bays and turning lanes for buses.

4.2.3 Arterial Roads:The function of arterials is to provide connection between collectors and major

highways.

Traffic volumes on arterials are high with medium to high speeds, and composed

of passenger cars and heavy vehicles. The arterial roads serve the traffic between the

traffic generation areas and main attractive centers; also it links with rural, collective

and local roads, and in areas where no highways, the arterial roads provide the best

traffic services.

Traffic volume on arterials varies from 5000 to 30000 vehicles per day and the

direction of traffic is divided by medians.

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Traffic flow in these roads is continuous except at traffic signals and pedestrian

crosswalks, traffic signals might be used to minimize interface to through traffic.

Parking in areas where stopping lead to serious interruption to traffic is prohibited

particularly at peak hours and it is preferable to allow pedestrian crosswalks only at

intersections or at special crosswalks.

Traffic flow is mixed and composed of passenger and heavy vehicles, the

percent of heavy vehicles may reach up to 20%, Arterials roads can be used with

express and local buses.

Arterial roads shall be connected with highways and other Arterial and it is not

preferable to connect local residential roads directly with arterial roads, and it is

possible to connect directly arterials roads with the industrial and commercial local

roads according to the site or traffic volume.

4.2.4 Highways (Freeways):

The function of freeways is to provide conditions for continuous movementwithout interruptions or crossings for heavy traffic volumes between the main traffic

generation areas.

They represent an extension of the main rural highways and they link residential

and large commercial and industrial areas with the commercial center of the city.

Parking and surface pedestrian crosswalks are prohibited on freeway and it should be

separated from the adjacent areas.

Traffic volume on freeways may exceeds 20000 vehicles per day and composed

of all types of vehicles, percent of heavy vehicles may exceed 20%. The movement of

express buses is allowed but bus stops are allowed only at interchanges.

These roads are connected with rural expressways and arterial roads, direct

connection to local roads is allowed only at the city center. And all crossings should be

grade separated intersections (interchanges).

4.2.5 Industrial roads:

The function of these roads is to provide traffic movements within industrial

areas and to connect these areas with roads of other types. This includes roads in

industrial areas and roads of bus stations, railway stations, airports and ports.

Traffic volumes may not be high, but the percent of heavy vehicles is high,

therefore when designing pavement layers they are treated as arterial or freeways. The

pavement layers in some parts may require special design and treatment for resisting

heavy loads such as good's container at storage areas in airports, ports and railway

stations. Also, they require special treatments for resisting oils and spilled materials.

4.3 Pavement thickness:

4.3.1 General:

The structural design process for road includes selection of pavement materials

and determining pavement layer thickness required to sustain axial loads of vehicles.Pavements are divided into two main types:

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The first type is the cement concrete pavements which is composed of cement

cast insitu or precast concrete layers or precast concrete elements placed on aggregate

subbase or base course Division 14 from these specifications includes the construction

specifications for cement concrete pavements.

The second type, which is more widespread, is the flexible pavement, which iscomposed of several asphalt concrete layers, aggregate base, and subbase and subgrade

layers. Divisions 5, 6, 8, 9, 12 and 13 of these specifications include the construction

specifications of asphalt pavement layers.

4.3.2 Pavement Thickness According to Urban Roads Classification:

Pavement layer's thickness is calculated and determined using several methods

and AASHTO method is considered the most widespread ones in the world. It requires

certain inputs that include design period, equivalent single axial loads (ESALs) in the

design period, environmental elements and soil bearing value like California bearing

ratio (CBR) or modulus of resilience (Mr) and other.

Whenever all design or part of the design data are not available the pavement

thickness indicated in Table 4.3.1 shall be used, these table shows the layer thickness

for flexible pavement in urban areas with low traffic loads only when the equivalent

standard axles loads in the design period (20 years) is less than one million axles, While

for roads with high traffic loading the design of pavement layers shall be carried

according to AASHTO design method or any other approved method. The pavement

layers shall be constructed according to the specifications indicated in the following

Divisions in these general specifications.

4.4 Correlation of Pavement layers With Non-Pavement Road Structures:

Urban Roads pavements are correlated with some non-pavement structures suchas internal and external pedestrian walkways, medians, trees, lighting posts, traffic

signals and sign and publicity boards …etc.

These structures require identifying some requirements, which include but not

limited to:

1. Sidewalk construction shall be in accordance with specifications stated in division 15

of these general specifications to.

2. Special areas with specific slopes shall be constructed on sidewalks near the traffic

signals and crosswalks, so they may be used by the handicapped with wheel chairs

and children carts. Division 15 shall be referred to for more details.

3.

Informatory signs, traffic and publicity boards shall be placed on sidewalks andmedians in such a way that does not obstruct pedestrian movement and reduce sight

distance for the drivers and it shall be installed according to technical conditions

stated for publicity boards issued by ministry of municipality and rural affairs, while

traffic signs shall be constructed according to unified traffic manual issued by

ministry of transport.

4. The planting works on sidewalks and medians shall be constructed according to

construction manual for planting and conditions and related technical specifications

issued by ministry of municipality and rural affairs.

5.

Extra water from trees and plants irrigation process shall be drained by using

required arrangements when executing the planted islands and provision of water

proofing and to prevent its leakage and collection on the road surface.

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6. Road lighting works shall be constructed according to technical specifications and

general conditions for roads and streets lighting issued by ministry of municipality

and rural affairs.

7.

Non-pavement structures shall be constructed in a reasonable sequence such that the

under construction works will not cause any damage to previous works.

Table 4.3.1: Guide of minimum thicknesses for urban road layersAsphalt layer thicknesses (surface and base)

/ aggregate base/subbase layer, (cm).

According to bearing capacity of the

roadbed.

Urban

Road Class

Traffic volume level

(ESALs) in 20 years

design period

Average

daily

number

of

truckspoor

3 <CBR ≤ 5

fair

5 <CBR ≤ 10

Good

CBR >10

Level 1

(less than 10,000)1 5/10/13 5/10/0 5/10/0

Level 2

(10,000-50,000)2-7 5/10/15 5/10/13 5/10/10

Local

residential

roads Level 3(50,000-100,000)

7-14 10/10/12 10/10/0 10/10/0

Level 4

100,000-250,000)14-35 15/10/10 12/10/10 12/10/0

Level 5

(250,000-500,000)35-70 15/10/18 15/10/0 13/10/0

Collectors

and

arterialsLevel 6

(500,000-1000,000)70-140 15/10/30 15/10/0 15/10/0

Notes:1. The pavement layers indicated in the table above shall be constructed over subgrade layer that

conform to the requirements indicated in section 5.5 from these specifications.2. The road bed is the soil that on which the subgrade layer shall be constructed as specified in

paragraph number 5.4.3 "preparation of road bed" from these specifications.3. When constructing in high or variable water level areas, sabkha soils and volumetric changed soils

areas, the required solutions for these problem and pavement layers thickness and type shall bestudied and specified before starting road construction.

4. The asphalt layers shall be constructed in layers its thickness shall be conform to minimum andmaximum requirements and limits for nominal maximum aggregate sizes used in mixes as indicated

in Table 8.5.5 of this specifications.5. Numbers from left to right show the asphalt layers thickness (wearing and base), aggregate base and

subbase course thickness, for example 15/10/18 means:

• 15 cm asphalt layers (it can be 5 cm wearing course and 10 cm asphalt base layer).

• 10 cm aggregate base

• 18 cm subbase layer

4.5 Environmental Principles for Urban Roads Construction:

This section indicates conditions to be applied for environment preservation

when constructing and operating urban roads and includes description of Contractor's

duties in various project stages.

Contractor shall recognize and abide with all environmental ordinances and

regulations related to all types of contamination, issued from the concerned authorities

and he alone shall incur the legal, financial and social responsibility for any breach to

them.

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4.5.1 Noise:

Contractor, throughout execution phases, shall refrain from using any machines

or equipments which transmit a noise of more than 70 decibels according to scale (A) at

a distance of (16) meters during the period between 6 AM and 7 PM.

When the Contractor is allowed to work at night the noise level shall not exceed

65 decibel.

Rock blasting shall not produce noise exceeds 128 decibel at any day time

Local limits shall be applied if they are stricter.

4.5.2 Vibration:

Contractor shall use machines and equipments when used or operated which

produce vibrations that do not lead to any damage on buildings, structures and public

utilities.

Contractor shall apply all possible methods and arrangements to limit harmful

effects on his employees resulting of using some vibration equipments and abide withthe specified working hours for those equipments.

When executing blasting rock excavation he shall set out the suitable plan for

controlling and monitoring vibrations. Resulting vibrations shall not exceed the limits

stated in the special specifications or section 5-3 excavation works of these general

specifications.

4.5.3 Air pollution:

Contractor shall calibrate all his machines, equipments and material and mixes

production centers so that their operation does not lead to the propagation of air

polluting gasses in rates exceeding those allowed in environmental standards approved

by the concerned authorities in the Kingdom of Saudi Arabia.

Contractor shall prepare a plan for controlling dust during materials producing,

mixing, transporting, spreading and compacting and during excavation and extraction

works. This plan shall include water wetting or using dust reducing materials at work

sites and covering materials during their transportation. Also, it shall include control on

dust in aggregate and other materials stockpiles and stores, control on dust and other

emanating materials in various production centers such as asphalt and concrete plants

and providing them with the required filters, periodic monitoring and calibrating

procedures.

Any plants or aggregate crushers or quarries or and other materials stores, which

leads to environment pollution shall not be constructed within urban areas.

Permission of such centers shall be subjected to the required acceptances from the

Ministry, the authorities concerned with environment and public health, and they shall

be subjected to monitoring and inspection periodically.

4.5.4 Material extraction and disposal sites:

Contractor shall extract the materials required for work execution from the sites

shown on the drawings and special specifications or those proposed by him and

accepted by the Engineer and he shall get the required written permission for usingthese sites from the concerned parties and property owner. It is not allowed to extract

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materials within urban areas, or where extraction leads to changes in natural landscape

and valley flow lines. Contractor shall level and process these sites and make them in

harmony with the surrounding natural environment at the end of using.

Contractor shall dispose surplus and unsuitable materials at sites shown on the

drawings and special specifications or those proposed by him and he shall get therequired written permission for using these sites from the concerned parties and

property owner and written approval from the Engineer. In all cases, the selection of

sites and method of disposal shall not lead to environmental contamination.

Disposal sites shall not lie within urban areas, water flow lines, and agricultural

lands or near water sources and reservoirs.

Disposal sites shall be leveled and processed in a way that makes them in

harmony with the surrounding natural environment.

4.5.5 Hazardous and dangerous materials:Contractor shall take all required precautionary measures to prevent any

environmental contamination as a result of using some materials considered as harmful

to environment such as oils and chemical materials, carry out all works and procedures

required when those materials spill for any reason outside areas in which they are

allowed to be used.

Generally, it is prohibited to use any materials considered to be harmful to

public health or environment before obtaining the acceptance, instructions related to the

methods and conditions and safety procedures when working with such materials.

Contractor shall, when he encounters during work execution any materials,

which may be considered harmful to public health or the environment, immediately

report about that to the engineer and dispose those materials at sites specified and

approved by concerned health and environment authorities using approved methods and

arrangements.

It is absolutely not permissible to dispose these materials randomly and at the

public dumping sites that are not designated for such materials.

4.6 Traffic Control during Construction:

4.6.1 General:Urban roads construction processes such as transportation, spreading and

compaction are characterized by their interlocking with each other and with other living

activities of the population such as moving, crossing, walking.. etc. Therefore, it is

paramount that pedestrians and vehicles traffic movement should be regulated at the

area of executing construction or reconstruction or maintenance works to ensure traffic

safety for road and street users and to ensure rapid execution with the required quality.

4.6.2 Traffic control procedures:

All traffic control works shall be done according to the traffic control devices

manual at work zones issued by the central commission for project coordination under

the supervision of the Ministry of Municipal and Rural Affairs on 1421H or anyamendments incorporated in it.

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At least the following procedures shall be applied for the purpose of traffic

control during construction:

1. Setting out a clear and comprehensive traffic plan, to eliminate traffic contradictions

with the execution activities.

2. Identifying alternative roads and the approximate time period for publicizing and

generalizing it through mass media, not less than two weeks before startingexecution, to ensure the safety of the roads network users and construction

employees.

3.

Construction of all required items for carrying out execution works such as

temporary detours and routes, warning and alarm signals, flashlights and

concrete and metal barriers. Contractor remains responsible for the operation

and maintenance of those items.

4.

Provision of the information campaign at the locations specified for traffic

direction in addition to special boards written in Arabic and English showing the

start and end of construction.

5. Construction of temporary routes separate from alternative roads and detours for

transporting the vehicles and equipments required for construction.

4.7 Work site protection:

Contractor shall make all the necessary arrangements and procedures required for work

sites protection of such as barriers placing and warning lights, fencing of work zones

and guarding when required and he shall construct stores for materials, equipment and

machines at the specified sites accepted by the Engineer and ensure their protection,

fencing and guarding. In addition, he shall install warning boards that identify the

project.

4.8 Maintaining or transferring utility lines:

Contractor shall, before he commences work, inspect site and coordinate with

various authorities to recognize various public utility elements, structures and lines

existing within work limits or those, which may be affected by them.

Contractor shall execute all works related to maintaining or transferring those

utilities according to the solutions and specifications approved by the client. Contractor

shall take all necessary requirements to maintain the utility works during construction

and prevent them from any damages that may affect them and he only bare any result of

any damage caused to those utilities, because of his failure in coordination or in

providing the required arrangement. The construction shall be done according to

installation manual issued by ministry of municipality and rural affairs in relation tocoordination, releases and arrangements.

Transferring works shall be executed so as to construct the transfer lines and

correlation structures and elements between the main lines and the lines transferred

before cutting services of the transferred utilities then transference is done for the

purpose of reducing the service cutting time to the least possible period.

Contractor shall Coordinate with, and approve detailed time schedule for these

works by the public utility owners. The beneficiaries of public utilities shall be

informed by dates and periods of service cutting before the specified time by not less

than two weeks through the information methods approved by the concernedauthorities.

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Contractor shall make all required arrangements for maintaining protecting

public utilities during execution from any damages, which may occur to them. He shall

choose suitable execution methods and equipments and carry out support works when

required.

Contractor is responsible for any damages may be inflicted on the public utilitylines and their elements as a result of his failure in making the required coordination,

arrangements and work execution. Contractor shall follow guide of public utility works

issued by the Ministry of Municipal and Rural Affairs.

Converting or removing works must be done that the new converting lines and

construction link elements between new and old lines must be available before cutting

and removing any structures, and converting will be done to reduce service cutting time

to lower limits. Contractor must coordinate with public structure owners for depending

the necessary solutions and detailed time schedule for such works, and inform them

with detailed dates and periods of service cutting before starting works with less than

two weeks, and that shall be done using general depending informing devices.

4.9 Common Transport Stops:

4.9.1 General:

This item includes construction of confined areas between the road pavement

edge and the right lane designated as side stops areas for buses and taxis. Those areas

are characterized by repeated stopping for relatively long periods until passengers and

their baggage are loaded and dropped. Also, these areas are characterized by slow

movement (causing creep) of buses which result in slipping and displacement for the

upper pavement layers causing asphalt corrugations in addition the possibility of the

spilling of oil and fuel from buses during their stopping. Therefore, it is vital to choose

suitable pavement layers for such conditions.

4.9.2 Construction requirements:

When the special specifications or drawings or other contract documents

indicate the construction of stop areas, Contractor shall comply with the following:

1. Use suitable Sub grade and aggregate bases according to the structural design and

according to materials and execution requirements indicated in sections (5, 6).

2. One of the two following options shall be used respectively for constructing buses

and taxis parking pavements:

-

First option: Using cements concrete pavement layers to avoid surface corrugationsand according to materials and execution, requirements indicated in division 14 from

these general specifications.

- Second option: Using asphalt mixes containing a high percentage of coarse

aggregate according to Table 8.2.2 as a guide for selecting asphalt works according

to roads and parking areas classification, or super pave Mixes as indicated in the

contract.

3. Some modifying materials shall be added to the asphalt mixes indicated above to

increase the capability of the asphalt binder for resisting distress. It is possible to use

any of the special polymer additives or a seal coat composed of rubber asphalt to seal

off leakage of oils and fuel to the asphalt pavement layers.

4.

Geometric design used shall ensure easiness of entrance and exiting from the parking and passengers. Pedestrian's sidewalks shall be constructed according to

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technical specifications for parking issued by ministry of municipality and rural

affairs.

4.10 Protection of Adjacent Streets from Wastes and Contamination:

Contractor shall take all the required arrangements and procedures required for

protecting roads and property adjacent to work areas from any contamination bymaterials and wastes resulting from his works such as:

- Using covered vehicles for transporting various materials

-

Keep of all his work sites clean and arranged.

- Disposal of all surplus and wastes products and materials promptly and it is not

allowed, in any way, to accumulate these materials within urban areas.

- At the end of the works contractor shall clean, arrange and evacuate all sites used by

him.

4.11 Drainage Works for Urban Roads:

Contractor shall construct all the urban roads drainage works indicated on the

drawings, special specifications and other contract documents according to specialspecifications requirements or section 5.7 of these general specifications. He shall drain

and protect all executed works from the effects of water. When designing the surface

drainage facilities considerations should be given to the volume of water as the highest

volume occurred during the 25 years to confirm that no permanent or temporary

accumulations of rain fall water

4.11.1 Surface drainage:

During designing and executing roads in urban areas consideration shall be

given to water drainage by applying the following:

1- Designing and executing all items of surface drainage such as culverts, surface or

under surface side drains, execution of granular filter layers, cross drains, catch

basins in such a way that ensures storm water and surface water draining rapidly and

prevent water collection permanently or temporarily on the road surface or by its

side or its leaking to its structural layers.

2- When constructing soil, aggregate, pavement layers for streets, Contractor shall

abide with longitudinal and cross slopes shown on the drawings and contract

documents for each layer, and it is not allowed, by any means, to achieve slopes only

for the surface layer and ignore that in the bottom layers.

3- Provision of surface drainage during construction from all executed layers and

provision of required and effective tools to achieve this drainage so that no damages

result for the roads, adjacent structures and environment. These works are subject tothe conditions indicated in each paragraph of the works that include requirements

related to drainage during execution of these general specifications and special

specifications of the project.

4- Surface water collected from sidewalks, paved shoulders and pavements shall be

drained picked before reaching traffic lanes by constructing traps, side channels and

catch basins.

4.11.2 Underground water drainage:

During the designing and construction of roads consideration shall be given to

existing, future, permanent and temporary underground water and to provide required

devices of under drains and control water level by methods that limit its effect on theroad performance. Those devices include, but not limited to, the following:

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1- Using soil materials and asphalt mixes that are not highly affected by water.

2- Construction of free drainage granular layers.

3- Using under and edge drains, Drainage pipes or geotextiles, geocomposites and

pumps required for pumping collected water to the drainage systems or catch basins,

or other suitable solutions and arrangements.

4.11.3 Drainage requirements for trees and plants irrigation water:

When designing and constructing roads and pavements consideration shall be

given to the effect of planting irrigating and arranging trees and plants in the medians

and sides on the functional operational and structural performance of the road. To

ensure that Contractor shall:

1. Control water irrigation and prevent it from reaching road surface or leaking into its

structural layers and damaging them or changing their properties in such a way that

adversely affect the road and its various structures.

2. Do not plant thick rooted trees since their roots may extend to the road bottom, its

structures and different elements and subsequently damage them or lead to the

concentration of moisture and the occurrence of deformations.3.

Abidance with the conditions and special specifications for planting and irrigating

trees and plants.

4. Sequence of construction works so that no mixing occurs between the agricultural

soils with the pavement layers materials, and when such a case occurs all the

required arrangements shall be made to remove the agricultural soil from affected

materials.

5. Do not plant trees that grow in such way that may affects the capacity and sight

conditions.

4.11.4 Sewage water drainage:

During the designing and executing of urban roads, consideration shall be given

to the effects of existing and future sewage water lines on execution operations, devices

and materials. When the construction coincides with the construction of sewage water

lines, the following shall be considered:

1.

Setting out a plan for the sequence of the road construction and drainage works such

as pipe installation and manholes construction, in order to fulfillment the required

compaction degrees for all roads layers.

2. Provision of connection between pipes and manholes according to the drawings

specifications and conditions indicated in these general specifications plus the

general technical specifications for utility works and the special conditions of the project.

3. Execution of embankment and compaction by using methods, devices and

equipments, which do not lead to dislocation or damage of joints between pipes.

4. Fulfillment of compliance of the manhole surfaces with the road final surface slopes.

5.

Not allowed to start backfilling around pipes and manholes before fixing the pipes

and hardening of their bases and joints and reaching the required strength.

6. Using the materials indicated in the special specifications and drawings for

backfilling around manholes and pipes and if no particular materials were indicated

then Contractor shall use materials of not less quality than those used and required

for the road layers. Backfilling shall be in layers with thicknesses provided required

compaction degrees.

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4.11.5 Water Draining During Construction:

When work conditions require, contractor shall provide equipments, labors and

devices required for draining and disposing drained water whatever its source, during

execution from work sites at the locations specified by the Ministry and in such a way

that does not lead to damage to the structures and properties. All environmental

conditions shall be considered and it is not permissible to dispose this water in privateor public property before obtaining the written acceptances for that. Contractor is

responsible for any damages, which may arise from this.

Contractor shall execute the required supports for excavation slopes using the

suitable methods.

Contractor shall not commence these works before he obtains the approval of

support, pumping and water disposal methods from the supervising authority.

4.12 Traffic Safety Requirements on Urban Roads:

Urban roads and city centers are characterized by the existence of conflictingmovements of pedestrian, road users and vehicle traffic movement. This conflict may

lead to traffic accidents and delay in trips and increase traffic congestion, the vehicle

traffic conflicts with pedestrian movement on both sides of roads or crosswalks and

during their movement from homes to their work, schools, entertainment and shopping

places. This requires setting out a traffic design that ensures pedestrians safety and

provides smooth, safe and comfortable traffic conditions through the suitable

organization of movement and construction of pedestrian sidewalks, footpaths, safety

barriers and side.

During execution contractor shall abide with executing all of traffic control

works and provide traffic safety conditions at work sites according to requirements

stipulated in the traffic control devices manual at work sites issued by the central

committee for projects coordination under the supervision of the Ministry of municipal

and rural affairs on1421H and all its amendments.

4.12.1 Sidewalks:

Sidewalks shall be designed so that they provide safe and comfortable

movement conditions for pedestrians. When placing some obstructions on sidewalks

this shall be done such that the remaining space is sufficient for the movement of

pedestrians. Also, consideration shall be given to the conditions and requirements

concerned with the movement of the handicapped.

Contractor shall apply the requirements and execution phases indicated in

division 15.

4.12.2 Pedestrian Crosswalks:

The following requirements shall be achieved:

1. Designating special crosswalks or pedestrian crossing at traffic signals for their

movement between the two sides of the road. Crosswalks shall be marked with

ground marks (paint) or raised marks (using special tiles) and the required traffic

signs shall be installed according to requirements indicated in division 16 from these

specifications and dimensions stipulated in the manual of traffic control deviceissued by ministry of transport.

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2. Designating special Crosswalks for pedestrians at sites other than traffic signals and

intersections sites such as schools, mosques, entertainment areas and commercial

complexes.

4.12.3 Safety Barriers:

The following requirements shall be achieved and refer to division 16 fordetails:

1. Installation of a concrete barrier at medians to prevent pedestrian crossing except in

the designated places.

2. Installation of a metallic barrier between the road edge and sidewalk to ensure

directing pedestrians to the specified crossing areas near the traffic signals or areas

designated for crossing.

3.

Installation of safety barriers (metal or concrete) near schools gates to insure the

safety of students when they come out of their schools and directing them to crossing

areas designated for that purpose.

4.12.4 Informatory signboards and panels for pedestrians and cars:The following requirements shall be achieved:

1. Traffic signboards shall be installed at the suitable places so that they provide the

drivers with the required message about pedestrian crosswalks areas and show

pedestrians the areas designated for crossing.

2. Those panels and signboards shall achieve all the requirements indicated in

division16 of these general specifications and the specifications issued from traffic

departments and authorities in the KSA.

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E_div 4 Urban Roads Characteristic

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Transcript of E_div 4 Urban Roads Characteristic