PICTURE BOOK COMMUNITY ~ qDRIVEN - DNELOPMENT THE WORLD RANK PICTURE BOOK THE GOOD AND THE BAD INFRASTRUCTURE Road and Bridge by : Ekart Hartmann Heinz Unger Picture Book The GOOD and The BAD Infrastructure Roadand Bridge Author : Ekart Hartmannand Heinz Unger Editor : Octaviera Herawati Photos by : Ekart Hartmann Published by : World Bank Office,Jakarta DecentralizationSupport Facilities(DSF) Office Jalan DiponegoroNo.8 Jakarta 10310 Phone : (62-21) 3148175 (hunting) Fax : (62-21) 31903090 Wesite : www.worldbank.org Printed in August 2006 All, or any part of this book may be reproducedfor training needs. For further information, please contact Octaviera Herawati Phone : (62-21)3148175 Fax : (62-21) 31903090 Ernail : oherawati@wboj.or,id ISBN : 979-97428-4-6 I N T R O D U C T I O N Development workers new to rural lndonesia are often surprised by how frequently villagers mentionthat their top development priority is to overcome their isolation.Hamlets want to be joined to villages: and villages want to have access to markets, schools, and hospitals.Ask a gathering of village men who live in remote parts of the country what tops their wish list,and eight times out of ten the answer will be that they would really like help to build a road or a bridge (just as many women will say access to clean water!). Indonesia is not an easy environment for roads and bridges. Earthquakes and their aftershockscrack their foundations, Landslidescover them in mud.Tropicalstorms lash them with the most bitter enemy that any road can face: little droplets of water that wash away their foundations, Innocent grasses spring up overnight, sending out roots and tendr~lsthat split road surfaces. Overloaded trucks crack their rocks, leaving behind deep ruts and cracked culverts. Good engineering can help village roads survive many of the challenges that nature throwns at them, Even without the heavy equipment of modern road-building, simple technologies can produce perfectly good roads.A well-built road can last for ten years or more,even with little maintenance. If good engineering can produce roads that bring the fruits of development to villagers, bad engineering can subtract years from the life of the roads and bridges built through the hard labor of rural people. Poor drainage means that water will pool, leaching away road surfaces. Badly placed, uncompacted rocks make for weak foundations that soonturn to washboard and mudpits. Soft anchorsquicklyproduce collapsed bridges,even human casulaties. Inshort, engineering matters. The purpose of this guide is to help village technical workers build better roads and bridges.It usesexamples both good and bad drawn from nearly eightyears of experience - - with the Kecarnatan Development Program (KDP). Even though all construction done by community, using simple. labour-insentive.it does not meanthat the quality is low. The content of this book is easy to understand because each picture are complimented by simple explanation. Therefore, it can be used as technical training manual. There is an expectation that this book may benefit not only in KDP but also other agencies, NGOsand community themselves. Inorder to serve itspurpose,critics,inputsand recommendations from the reader would be highly appreciated for better revision in the future. Finally, we would like to thank to all parties who gave assistance in preparing this book. We wish that this book could give a benefit for better infrastructure development in the community-baseddevelopmentprojects. ACKNOWLEDMENTS All photographsand text were prepared by Ekart Hartmann and Heinz Unger based on the supervision missions conducted in several KDP locations; West Sumatra, South Sumatra,West Java, Central Java, South Sulawesi, South East Sulawesi, Bali and East Nusa Tenggara (NTT). Octaviera Herawati oversaw the production of these texts from field survey to publication and provided Indonesian translation, with overall guidance from Victor Bottini. Sentot Satria providedinvaluableassistance in selecting field locations. Scott Guggenheim,Victor Bottini, Enurlaela Hasanah, Sentot Satria, Richard Gnagey and Suroso Yoso Oetomo also contributed comments and input. Field support was also provided by the National Management Consultant (NMC) in Jakarta and the Regional Management Unit (RMU) inthe provinceslistedabove.Fieldstaff facilitated visits to KDPsites. Special thanks to Scott Guggenheim for his ongoing support. Contents 1Good Page Page Introduction........................................................... i Acknowledments.................. ....... ................. .. .. .... iii R O A D Construction GravelRoad Telasah Road TelfordRoad ConcreteRoad RetainingWall EarthWork Drainage Ditch Culvert B R I D G E Construction Concrete Slab Steel Suspension Abutment River Bank Protection - - Design - Construction- 0& M - Environmental Impact River gravel is too roundand is generally not suitablefor road construction (Picture shows a road 3 month after completion of construction) How can I d o it better ? GRAVEL ROAD Surface Material - Compact the materialwith heavy equipment,and vibration if possible. Use angular stones with sharp edges. Check availabilityof suitable material prior to construction. WHY ? The stones for the surface layer shall be angular, rough and sharp-edgedso that they interlock with each other. To make the road withstand traffic loads and minimize O&M work. The excavation of gravel from a river bed may cause changes to the flow of the river + Environmental Impact. Piclure Book - Road and Bridge 1 Design - Construction- 0& M Environmental Impact - 2 Picture Book -Road and Bridge Design - Construction 0 81M - Environmental Impact - I surfacem a t m too fine I The materialfor the surface layer is too fine, not bound and not well compacted How can I do it better ? GRAVEL ROAD Surface Layer - Compact again and add a new layer of suitable stones on top. WHY ? The material for the surface layer shall be angular, rough and sharp-edged so that they interlock with each other. To minimize O&M work later on. Looselycompacted materialwill be washed out and driven off quickly. Picture Book - Road and Bridge 3 Design Construction - 0 & M - Environmental Impact - The material on the shoulder is too fine and not well compacted How can I do it better ? GRAVEL ROAD - Shoulder Compact the shoulder again and add a layer of angular stones on top. WHY ? 'The compacted shoulder gives lateral support for the road structure. The water flow from the road surface will not erode the shoulder, if the shoulder material is suitable and well compacted. 4 Picture Book -Road and Bridge Design- Construction - 081M - Environmental Impact ILoadpushes I Row of bic I the stone stones at th edge is OK I There is no side support for the bigstones Traffic loads will pushthe stones aside How can I do it better ? GRAVEL ROAD Shoulder - Build a well compacted shoulder. WHY ? The big stones at the edge of the road must be supported by a solid shoulder,otherwise the stones will be pushedout and the road will fail. Picture Book - Road and Bridge 5 Design - Construction- 0 & M- EnvironmentalImpact I gzng in the cente Grass the r m d Without O&M the roadsurfacewill soon become a lawn. How can I do it better ? GRAVEL ROAD - Vegetation Cut the grass and removethe rootsat leasttwice a year (O&M). Makesure that the roadsurface can drain freely to the ditch(es) by removingearth and vegetation regularlyfrom the shoulders (periodic O&M). Builda crownfor the roadwith a new gravel layer. WHY ? Grass is an indicator for poorly organized O&M. Without maintenance, grass will grow anywhere, even on a gravel road. Grass and plant roots will slowly damage the road. Picture Book -Road and Bridge Design - Construction- 0 & M - EnvironmentalImpact Shrubsgrowing on the Grassgrowhgon the road Without O&Mthe roadsurfacewill soon be overgrown by vegetation (Picture shows a road4 monthafter completionof construction) How can I d o it better ? GRAVEL ROAD Vegetation - Cut all vegetationand removetheir roots(O&M). Makesure that the roadsurface can drain freely to the ditch(es) by removingtopsoilandvegetation regularly (periodic O&M). Builda crownfor the road with a new gravellayer. WHY ? Grass is an indicator for poorly organized or not executed O&M. Grass will grow anywhere. even on a gravel road. Grass and plant rootsw~llslowly damage road. Picture Book- Road and Bridge 7 Design- Construction- 0& M - EnvironmentalImpact 1%rubs grow on hou~ers I 8 Picture Book -Road and Bridge Design - Construction - 0& M I I Larger rocks Inthe centre line of the road pziGzzr b e b e e n centre and Telford road How can I do it better? TELFORD ROAD Replacethe bigger rocks in the centre linewith the rockswhich have the same size as in the right and left sides. Fill the cracks and holeswith the sand and gravel mixture to make smoothens the surface of the road. WHY ? It would be difficult to make a good crown if the larger rocks placed in the centre line. Alternative: A road with a concrete slab. Picture Book - Road and Bridge 9 Excavatefor ther larger Constructiondetails of a Telford road Picture Book -Road and Bridge Design - Construction- 0 & M - EnvironmentalImpact Sand layer is less than 10 cm thick and is not according to detailed design How can I do it better ? TELFORD ROAD - Details Check the thickness of the different layers against the design. Excavatemore, if the excavationis not deep enough for road sub-base and base layers. In the case shown above,the sand bed was not thick enough. WHY ? The depth of the different layers are specified inthe cross sections & specifications. If the layers are not done as specified,the road surface will break up fast, and will in a lot of repair and O&Mwork later, Picture Book - Road and Bridge Design - Construction 0& M - EnvironmentalImpact - Shoulder is missingand the edge of the road slab is broken How can I do it better ? CONCRETE ROAD Detail - A compacted gravel shoulder will protectthe edge of the road slab. Watch for the correct mixture of concrete (gravel / cement/ water) to get good quality concrete which does not chip off easily. WHY ? A shoulder shouldsupport and protectthe edge of the roadslab. Do not removethe formwork of the slab too early. Do not save cement - take the right mixture. Picture Book -Road and Bridge Design - Construction- 0 & M - EnvironmentalImpact \ ConcreterampIs needed I here r l \ -.J Stones at the twrd of not end with a deep drop How can Ido it better ? CONCRETE ROAD - End of road Builda concrete ramp at the end of the roadslab. The last element of the slab must havea slope and is dug into the natural ground to get rampedtransition. Placesome larger rocks at the end of the ramp - top edge at the same level as the concrete. WHY ? Vehicles cannot drive over a deep drop without getting damaged. The rocks at the end of the ramp will protect the concrete edge. Picture Book - Road and Bridge 13 Erosionmarks madeb No erosion protection of the fill (embankment) secrlon Side slope is too steep How can Ido it better ? EARTH WORK Fill Section - Considerthe naturalangle of reposeof the material. Fill sections haveto be compactedvery well using heavy equipment. For steep slopesconsider to builda steppedembankmentfor greater stability. Prevent uncontrolledwater discharge from the roadsurface by sufficiently large drainage ditches and drain away from the down slope. Plant vegetations (shrubs, trees) on the steep slopes to increase stability. O&M hasto keepan eye on the embankment until naturalsettlement has consolidatedthe fill. WHY ? The natural angle of repose of the fill embankment must be considered and the slope of the embankment must not be steeper. Flowingwater causes erosion which will wash out steep. Roots of shrubs and trees can strengthenthe fill section. 14 Picture Book -Road and Bridge Design Construction 0 & M - - Consider the naturalangle of reposeof the material in the cut How can I do it better ? EARTH WORK -Cut Section Consider the naturalangle of reposeof the material inthe cut section. Consider constructing a stepped embankment (terracing)to make steep slopes more stable. Makesure water can drain easily +sufficiently largeditches are needed. Plant vegetation (shrubs,trees) on the steep slopesto increaseslope stability. Why ? Consider the naturalangle of repose of the slope material. The slope of the cut must not be steeper than the naturalangle of repose. On steeper slopes the materialis unstableand will collapseslowly. Flowingwater causes erosion - washing out the slopes. Roots of shrubs and trees increase the stability of a cut / fill section. Picture Book- Road and Bridge 15 Design - Construction - 0 & M I w Ditchwith w# crown naturalslopes I as shown In deslgn ICentre Line I Gravel road Why is it better ? GRAVEL ROAD The angular stones of the surface layer ensure a smooth and durablesurface. The shoulders support the gravel surface and prevent washing out of the road surface. The natural slopes of the ditch will not cause erosion. Alternative: No. A Telford road maybe,but this type is better used on steep sections only. 16 Picture Book -Road and Bridge Design Construction- 0 & M - Gravel road with a good surface layer Why is it better ? GRAVEL ROAD - Surface The stones of the gravel layer are broken and compacted by a roller (heavy equipment),which ensure a smooth and durable surface. The wall of the ditch supports the gravel surface and preventswashing out of the road surface. Alternative: There is no alternative to a good surfacelayer with angular stones and a good mixture of stone sizes. A Telford road maybe, but this type is better used on steep sections only, - = Picture Book - Road and Bridge 17 Design - Construction 0 & M - Well-built Telasah road Why is it better ? TELASAH ROAD Flat stones are well arrangedto form a smooth surface and still provide good friction. Alternative: A Telford road, but the surface is not so smooth. A road with a concrete slab. A asphalt road which is much more expensive. 18 Picture Book -Road and Bridge LI Design Construction 0& M - - r Concretetracksslab Economicalconstruction of a concrete road Why is it better ? CONCRETE ROAD Concretesurface should be usedon steep sections or when flooding of the road is likely to happen. The distance betweenthe two tracks shall not exceed 80cm because of the average distanceof the wheels of the cars. The permeable sand and gravel mixture betweenthe tracks must be compacted, but shall also drain away the water flowing from the tracks. A complete concreteslab (not separate tracks) is preferable in curves. Alternative: A road with a complete concreteslab. Picture Book - Road and Bridge 19 I Design - Construction - 0 & M Roadwith a concrete slab Why is it better ? CONCRETE ROAD Concrete surface shall be used on steep sectionsor when flooding of the road is likely to happen. Grooves in the surface increase the roughnessfor better friction. Alternative: A road with two concrete tracks. The patternof the grooves can vary (see next page). 20 Picture Book -Road and Bridge Design - Construction- 0& M for slopes up to 3 % I I < v u y I I CUIK l W l W S U l l U C W for slopestrom 3 to 7 % ", Design- Construction- 0 & M t; . . ... . . ::* I . . , , r - ".' . Y ,\.." , " ;*#.,. *.::;;.; . " ::I. , ' . ., . r,.; . .' V.'. ~.' * . h . 1- , t< '* ' .. -. J . .:.;,.., , . . .., , A , :?2 -,, ;\ ;J.+ * I , , . IConcrete ( dab Roadwith a concreteslab on steeper roadsection Goodtransitionfrom gravel surfaceto concreteslab Why is it better ? CONCRETE ROAD Concretesurface should be used on steeper sections. Groovesinthe surface increase roughnessand frictionfor vehicles. Alternative: A Telford road on steeper sections, 22 Picture Book -Road and Bridge Design Construction - 0 & M - Retainingwall along a gravel road Why is it better ? RETAINING WALL A retainingwall needsnot so much space, but is much more expensivethan a road on an embankment with naturalslopes. Weeping holes in the retainingwall (especiallythe in the lower portions)for drainageof the road sub-base are essential for a dry road. Alternative: Road on filled embankment. Picture Book - Road and Bridge 23 I Design Construction- 0& M - I $ = weeping holes I Retainingwall Dischargewater drained from behind a retainingwall Why is it better ? RETAINING WALL If the drainedwater cannot discharge from behindthe wall,the water pressure will rise and will put pressure on the wall. The wall could break or fall over ! Placethe pipes in a regular pattern,with more inthe lower portionsof the wall. Alternative: No. 24 Picture Book -Road and Bridge Design - Construction - 0 & M Replantingthe bareslopes of fill section Why is it better ? EARTH WORK - Fill Section New fill sections haveto be plantedwith shrubs and trees to increaseslope stability. The naturalangle of repose of the material has been considered. Alternative: A retaining wall can shorten the length of the side slope, but it is more expensive. Picture Book - Road and Bridge Design - Construction - 081M Environmental Impact - I Noe prevt,,,,,, , How can I do it better ? DITCH Smoothen the sides, if possible. Lay stones on the sides of the drain. Build a masonry (or concrete) wall. WHY ? Erosion materialwill fill the drain with soil after heavy rains and the force of flowing water will destroy the sides of the drain. Blockeddrains stop the flow of water. Dammed up water will damage the road'ssub-base and base, and it can overflow and wash out the road surface. Picture Book- Road and Bridge 26 Design - Construction 0 & M EnvironmentalImpact - - shoulder vvulerC U ~ ~ ~ I O I 11110 rurl Tne araln Decauserne rop eage is higher than the shoulder of the road. How can I do it better ? DITCH Cut notches (lengthabout 30cm) inthe top of the drain, spacedabout 5m apart. Extendthe asphaltsurfaceallthe way to the ditch. Watch the slope of the roadsurface, makingsure there is a crown inthe center. Clear vegetationfrom shoulder so water can flow intothe drain (O&M). WHY ? If the water cannot flow into the roadside drain, it will flood the road and shoulder, and damage them by washing out the surface. 27 Picture Book -Road and Bridge Design - Construction 0 & M - EnvironmentalImpact - of repose Erosion material dams up the water flow in the ditch Standing water causes vegetation growth in the ditch How can I do it better ? DITCH Excavation - Remove all material steeper than the natural angle of repose. If this is not possible a retainingwall should be built. Ensurethat the water can flow in the roadside ditch +O&Mwork must clean the ditch periodically. WHY ? The naturalangle of repose must not be ignored. Water cannot flow if roadside ditch is blocked by eroded material. Picture Book - Road and Bridge 28 Design Construction 0& M- EnvironmentalImpact - - rturalangleof repose 4 Eroded material . .. Actual I Water cannot drain away - it will flow on the road surface and will damage it How can I do it better ? DITCH - Road Surface Removethe high ridgeon the left side so the water can drain over the shoulder. Builda ditch on the right side. Make sure that the water can flow over the shoulder and to the roadside ditch. Cut back the excavated slope to the natural angle of repose. O&Mmust removethe eroded material. WHY ? If water cannot drain away, it will flood the road and wash out the surface. Water should be moved away from the road surface as fast as possible. 29 Picture Book -Road and Bridge Design - Construction 0 & M - Environmental Impact - IDeslgnedcrosssectionI Srass on the road shoulder warer cannor rlow lnro rne araln Decause rne snoulaer is overgrown with vegetation and higher than the ditch How can I do it better ? DITCH Road Surface - Removeearth and vegetation on the road shoulder. Deepenthe ditch. O&Mhasto keep the shoulder free of grass and the ditch clean. WHY ? If the water cannot flow into the roadsideditch, it will saturate the road base and damage the surface (see following page), Picture Book - Road and Bridge 30 Design Construction - 0 & M Environmental Impact - - -1 Earthfill and Water flow *,egetationprevent section dater flow to ditch Examples of water flowing on the road surface and the resultingdamage 31 Picture Book -Road and Bridge Design - Construction 0& M - EnvironmentalImpac' - ' Roadsurfacewashed out steep section I I Washedout materialot road I surface layer f l j Water cannot run into the drain - the surface road layer will be washed out How can I do it better ? DITCH - Road Surface Ensure that the water can flow into the roadside ditch. Compact the surface layer with a roller again. O&Mmust deal with this problem. WHY ? If the water cannot flow into the roadside ditch, it will flood the road and damage the surface by washing out. Picture Book - Road and Bridge 32 Design - Construction 0& M - Environmental Impact - ashed out material of surface layer beep run rn roaa surrace causedby water flow 1 Design- Construction 0 & M - Environmental Impact - Picture Book - Road and Bridge 34 Design - Construction - 0& M - EnvironmentalImpact I C Placelargestones adjacent to the culvert outlet Formwork that is not removed can block the culvert making it useless How can I do it better ? CULVERT Removeall formwork from insidethe culvert (after concrete has reachedfull strength). Place large stones the outlet of the culvert to prevent erosion. WHY ? Formwork that is not removedwill rot eventually,drop down and obstruct the free flow of water. 35 Picture Book -Road and Bridge Design - Construction 0 & M Environmental Impact - - A Formworknot removed The inlet area of the culvert is blocked by formwork that has not been removed How can I do it better ? CULVERT Remove all formwork, also from the inside and outside of the culvert (after concrete has reachedfull strength). Excavatearoundand deepen the inlet of the culvert +see inlet box ( +see Good Examples). WHY ? Formwork that is not removed will block the culvert. The free water flow has not be obstructed. Picture Book - Roadand Bridge 36 Gravel and sand block the culvert inlets and wlll dam up the water How can I do it better ? CULVERT Keepthe culvert inletsfree from sand and gravel the water mustflow - through the culvert +O&M. Builda sandtrap upstream of the culvert to preventaccumulation at culvert inlets(sandtrap will haveto be cleanedperiodically). Makethe necessaryprovisionsduringthe design phasealready. WHY ? When water is dammed up in front of the blocked culvert it overtop the road and wash out the surface or do even more damage. 37 Picture Book -Road and Bridge Damagecaused by poor water managementon roadand aroundculvert Culvert pipesare broken How can I do it better ? DITCH - Water Discharge Cover culvert pipeswith concrete (minimum 15 cm cover). Add soillgravel mixture layer on top and compact properly. Ensurethat the water of the adjacent roadsections can flow freely into the roadside ditch --,O&Mhasto clean the ditches periodically. WHY ? Flowingwater can easily erode a gravel roadsurface or even the base of a road. Makesure that the water can flow the shortest route to the roadside ditch. When water is dammed up in the ditch, it will flood the road, especially when in cut, and will destroy the roadsurface or even the base (see picture). Picture Book - Road and Bridge Well shaped earth ditch with natural slopes Why is it better ? DITCH The naturalslopes of an earth drain hold up well against erosion. A ditch with naturalslopes reduceserosion and that means less 0& M. Always respectthe minimum width (top & bottom) and minimum depth of a ditch. Alternative: Stone masonry or concrete ditch (more expensive, but easier for O&M. 39 Picture Book -Road and Bridge Design - Construction - 0& M sectionas shown in design Slopeset back from the ditch Why is it better ? DITCH Water is quickly transported away. Roadand shoulder are protectedby the masonry walls from the eroding force of flowing water. Alternative: Earthdrains,but they need much more space and are less stable; earth ditchesalso need a lot of more maintenance. Picture Book - Road and Bridge 40 Design - Construction- 0& M Ditchwith vertical plasteredmasonry walls I Roadsurfacewith goodcrown Very well built Telford road and masonry ditches Note : Road shoulder is not finished yet. It should be filled in to protect edge of the road and to allow drainage into the ditch Why is it better ? DITCH Ditcheswith a hardsurface have largeflow capacity. Road shoulders are protectedagainst the force of flowing water by the masonrywalls of the ditches. Ditcheswith a hardsurface are easier to clean +less maintenance. Alternative: Earth drains, but they need much more space and are less stable; earth ditches also need a lot of more maintenance. 41 Picture Book -Road and Bridge Design- Construction- 0& M I I Placelarge stones od10cent to the drop Dropstructuresare requiredin a steep ditch Why is it better ? DITCH Drop structures in a steep ditch (larger than 2% slope) reducethe force of water and that means lesserosion of the invert of the ditch. Alternative: Invertof ditch made of concrete or stone rip rap. Picture Book - Road and Bridge 42 Design - Construction - 0& M Water flow in concrete invert and side walls I 7 npecutvert lnlet box for a pipe culvert Why is it better ? CULVERT lnlet - lnlet box traps erosion materialfrom enteringand blockingthe culvert. The minimum diameter of a pipe culvert should not be less than 40 cm. Maintenancemust keep the inlet box clean. Alternative: Insteadof concrete for the walls masonry or stones could be used. - 43 Picture Book -Road and Bridge Design - Construction- 0 & M JII W' walls k0 Isonry Why is it better ? CULVERT - Inlet Ditch runs into an inlet box before entering the culvert. Diameter of the culvert has to be big enough (min.diameter 40 cm). Maintenancemust keep the inlet box clean. Alternative: Concrete walls, Picture Book - Road and Bridge 44 Design - Construction - 0 & M Why is it better ? CULVERT - Outlet Water is channelled away from the culvert. Large stones adjacent to the concrete outlet structure prevent washing out or undercutting of the structure. Length of protectiondependson the maximumflow but should be at least 1 meter. Alternative: Insteadof concrete for the walls and bottom - masonry or stone riprap could be used. Picture Book -Road and Bridge Design - Construction- 0 & M 0 J l U l l W > U U J U L W I l l lU I l l ' structureare essentia Effectivewater discharge away from a culvert outlet Why is it better ? CULVERT - Outlet Flow from the culvert outlet is channelledaway from the road. Largestones adjacent to the concretestructure angular stones have to be laidto prevent a washing out or undercuttingof the structure. Length of stone protection depends on maximumflow but should be at least 1 meter. Alternative: Concrete walls, Picture Book - Road and Bridge 46 Design Construction - 0 & M - Outlet of a culvert Why is it better ? CULVERT Outlet - Large stones adjacent to the culvert prevent erosionand washing out of the structure (length dependson max.flow but should be at least 1 meter). Wing walls made of masonry. Alternative: Lengthen the concrete invert of the culvert (see previous page). 47 Picture Book -Road and Bridge lsonry wing 1 Water flow Box culvert outlet Why is it better ? CULVERT Outlet - Box culvert is a good alternativeto a small bridge. Construction is more simpler and cheaper. Large stones should be placed adjacent to the drop structure to prevent a washing out or undercuttingof the structure. Lengthof protection depends on maximumflow but should be at least 3 meter for larger structures. Alternative: Small bridge, but it is much more expensive. Picture Book - Road and Bridge 48 Design- Construction 0& M - EnvironmentalImpact - Water left on steel causes rusting How can Ido it better ? BRIDGE - Rust Make the necessary provisionsduring the design phase already, so that water will not be trapped or sit on steel surfaces. Periodically check all critical pointswhere rust can establish itself (O&M). Removeall rust with a steel brush and paint with rustproof paint. WHY ? Rustysteel loses its strength. Picture Book- Road and Bridge 49 Design - Construction - 0& M - Environmental Impact Formworkfrom under the concreteslab must be removed How can I do it better ? BRIDGE Formwork - Remove all formwork (after concrete has reachedfull strength). WHY ? When the wooden boards rot,they will fall down. Wood absorbs and holds moisture.and this may cause the steel beamsto rust quickly. 50 Picture Book -Road and Bridge Design- Construction- 0& M EnviromentalImpact - ree openlng I bed I Tree trunks in the river block and dam up the water How can I do it better ? BRIDGE - Clear Opening Keepthe opening free of any material - the water must be able to flow freely under the bridge- O&M. WHY ? When water is dammed up in front of a blocked bridge it will become a hazardfor the bridge itself. The dammed up water may overtop the road and could cause serious damage to the roadand surroundings. Environmentalimpacts,i.e,flooding could arise. Picture Book- Road and Bridge 5 1 Design - Construction - 0& M EnvironmentalImpact - Pedestrianscan break through rottenand broken boards of the decking How can I do it better ? DECK Check the condition of the decking boards periodically. Replace any rotten boardsand use good quality hardwood. Paintthe boardswith protective coating. WHY ? Risk of accident for the users. The stability and structural integrityof the bridge are potentiallyaffected. 52 Picture Book -Road and Bridge Design - Construction - 0 & M EnvironmentalImpact - I Rotten boards and beam Damagedand missing and rotten decking and beams illustratepoor 0& M How can I do it better ? DECKING Check the condition of railings,boards and supports of the decking periodically. Replacethe damaged parts without delay. WHY ? Risk of accident for the users. The stability and structural integrity of the bridge are potentially affected Picture Book- Road and Bridge 53 Design - Construction - 0 & M - Environmental Impact Good maintenanceis essentialto keep a suspensionbridgesafe and in good shape How can I do it better ? CABLE Turnbuckles are essential to keep the cable at the right tension. Clean and oil the cable periodically. Keep water and wet mud away from all steel parts ' danger of rust ! WHY ? The cable is the load bearing element of the bridge keep it in good - condition. Avoid rust- it will destroy the steel elements of the bridge. 54 Picture Book -Road and Bridge Design- Construction - 0& M - Environmental Impact ICable shouldbetaut A slack cable is useless How can I do it better ? CABLE Check the loops and replace the broken ones. Check the cable runningthrough the loopsand it. Protectthe steel elements against rust. WHY ? The cable must be to connected to all supports for greater stability of the bridge. Picture Book - Road and Bridge Design - Construction- 0& M EnvironmentalImpact - View from the bottom View from the top Bsnt hanger rock - The hanger rods should be screwed to the supports. IUOT bent ! How can I do it better ? HANGER Replace hanger rods and use threaded connectionsto the supports Protectthe steel elements against rust coating. WHY ? The hanger rods transfer the load of the bridgeto the suspension cable - keepthem in good condition. Use of a threaded connection allows adjustment of hanger rod length use - two nuts for each hanger rod to prevent loosening of the connection, Avoid rust +it will destroy the steel elements of the bridge. Picture Book -Road and Bridge Design- Construction- 0& M - EnvironmentalImpact 'iCable I Deck View from the bottom Watch out for the criticalpoints for rust and rottingwood How can I do it better ? SUPPORT Keepthe critical points clean and protectthem with water resistantcoatings Use two nutsfor each hanger rod. WHY ? The supports are carrying the load of the bridge- keep them in good condition. Avoid rust +it will destroy the steel elements of the bridge. Picture Book - Road and Bridge 57 Design - Construction - 0& M 1 Abutments builtof -mw] Bridgewith a concrete slab Why is it better ? CONCRETE SLAB BRIDGE A concrete slab bridge shall not exceed 6m span. 8 Longer bridge over a deep valley avoids steep approach sections. 8 The abutments are made of stone masonry with a height of more than 8 m. Alternative: "Dutch-style"arch bridge. 58 Picture Book -Road and Bridge Design Construction - 0& M - Concretearch stone masonryside walls "Dutch-styl~~ r c bridge h Why is it better ? CONCRETEARCH BRIDGE This type of bridgeis suitablefor spans up to 10 m. The arch and the abutments are made of concrete. The walls are made of stone masonry and rock fill in between. The appearance of the bridge is very nice. Not suitable for rivers with high flood flows. Alternative: A steel girder bridge. Picture Book -Road and Bridge 59 Design - Construction- 0 & M Steel girder bridge Why is it better ? STEEL BEAM BRIDGE For larger span, i.e. more than 6 m, a steel girder bridge is most suitable. The abutments are made of stone masonry. BUT good maintenance is needed to prevent rust formation. Alternative: None. 60 Picture Book -Road and Bridge Design - Construction 0 & M- I- Wooden deck on steel masonry framewith steel raillngs Suspension bridge Why is it better ? SUSPENSION BRIDGE This type of bridge is suitable for spans up to 100 m. This bridge is for pedestriansand motorcycles only. Good 0& M is essential,especially to prevent rusting. Alternative: No. Picture Book - Road and Bridge 61 Design Construction - 0 & M - Constructiondetails of a suspension bridge Why is it better ? SUSPENSION BRIDGE, Details Steel cross supports are preferablebecauseof they last longer. Decking boards should be paintedwith weather resistant coating. Good 0& M is essential. Alternative: No. 62 Picture Book -Road and Bridge Design - Construction- 0& M Drainageof retainingwalls, abutmentsand wing walls Why is it better ? ABUTMENT or RETAINING WALL If the suckedwater cannot dischargefrom behindthe wall, the water pressure will rise and exert pressureon the wall. The wall couldfail, i.e. develop cracks or topple over. Weeping holes use PVC pipes,but bamboo or other materials could be used as well. Alternative: No. Picture Book - Road and Bridge 63 Design Construction 0& M - - Protectionof river banks and bridge abutments Why is it better ? RIVER BANK PROTECTION Gabions consist of rocksor iver stones in a galvanized wire mesh cage - a simple but very effective construction element. Use gabions as protectionfor bridge abutments and for adjacent river banks. Alternative: Wing walls of masonry or concrete. Stone riprap. 64 Picture Book -Road and Bridge PROGRAM PENGEMBANGAN KECAMATAN (PPK) THEWORLD BANKOFFICE JAKARTA JakartaStockExchangeBuildingTower II/ 12thFI. JI.Jenderal SudirmanKav.52-53Jakarta, 12910lndonesia Phone :(62-21)52993000 Fax :(62-21)52993111 website :www.worldbank.org DECENTRALIZATIONSUPPORT FACILITY (DSF) JalanDiponegoroNo.8 Menteng,Jakarta Pusat,10310Indonesia Phone :(62-21)3148175 Fax :(62-21)31903090