Highway Design - Research Paper Example

Highway Design Highway Design TASK Referring to Diagram Existing Factory Road Layout, Factory Road is a stretch of rural road that requires realigning to accommodate a new factory complex, but no access to the new complex is necessary. The road is a 7.3m wide, single carriageway rural road, has a low/medium frequency of accesses with a 1.5m wide verge both sides, and a design speed of 85kph. The overall ‘bendiness’ of this stretch of road has been measured at 270°/km, and a harmonic , but this did not take account of the required standards for highway design in the UK. Mean visibility (VISI) of 480m. The developer has already proposed a realignment design, shown in Diagram 2.Proposed Factory Road Realignment The realignment needs to accord with the guidance set out within Volume 6 - Road Geometry of the Design Manual for Roads and Bridges (DMRB) in order to be acceptable to the local authorities. a] - Design a suitable horizontal alignment, with transition curves for two compound curves based on the previously proposed layout sketch (Diagram 2), minimising the length of new road to be constructed. Use Diagram 1 as a template for the realignment design. Response to (a) Existing straight 700m radius with 1 m curve widening Proposed realignment 680 m long straight 700 m radius with 1m width curve 200 m long straight Existing 700 m radius Design of a suitable horizontal alignment Existing Chain age Existing Chain age Proposed Chain age Proposed Chain age Speed Remarks Start End Start End K.P.H 307/092 308/539 307/092 308/684 25-50 Rural Area 309/567 313/591 309/826 314/317 40-50 Rural Area 345/115 347/020 346/250 347/164 65 Rural Area Key: K.P.H – Kilometre per Hour Scale 1: 1000m [b] Calculate the required setting-out data so that a centre-line for the construction of the road can be marked out by on-site engineers. Note the origin of the setting-out chain ages should be the intersection of the two straights. Show all stages of the calculations, using tables where appropriate. Response to (b) Calculations of centre points Left Hand Readings Right Hand Readings Centre Point Speed(K.P.H) Remarks 30000 29000 29500 85 Rural Area 37000 30000 33500 85 Rural Area 38000 37000 37500 85 Rural Area 35000 39000 37000 85 Rural Area 33000 37000 35000 85 Rural Area 30000 33000 31500 85 Rural Area 28000 31000 29500 85 Rural Area 27000 35000 31000 85 Rural Area 26000 29500 27750 85 Rural Area 27000 29000 28000 85 Rural Area 28300 29600 28950 85 Rural Area 27300 28000 27600 85 Rural Area 26300 28000 27100 85 Rural Area 25300 25000 25150 85 Rural Area 24500 20000 22 250 85 Rural Area Note: In obtaining the value on the centre line found the average of the maximum and the minimum value on the diagram 3. The diagram of the centre line road setting will be as shown below where the measurements are in metres. The scale used is 1:1000m The centre line is obtained from the set data on the measurement on diagram three of the proposed factory construction. The centre line is obtained by finding the average of the maximum and minimum measurements found on the right and left on diagram 3. This is the established useful line for the construction of the new road. The upper and lower ends of the proposed centre line still maintain the existing road lin 21250 23000 24750 26000 29500 37500 35000 31500 29500 31000 27750 28000 28950 27600 27100 25150 22250 [c] Using the data provided by Diagram 3.Factory Road Levels Survey, design a suitable vertical alignment including cuttings or embankments, 2m wide verges, and slopes to be at 1:2gradient on all sides. Ensure that horizontal visibility is considered and adjust the verge width where necessary. Write a brief report explaining any assumptions and how the various elements of the design were selected. Response to (c) Vertical Alignment The Right Hand Side Median Edge Proposed Factory Complex Speed(K.P.H) Remarks 19500 85 Rural Area 21250 85 Rural Area 23000 85 Rural Area 24750 85 Rural Area 26500 85 Rural Area 28250 85 Rural Area 30000 85 Rural Area The Left Hand Side Median Edge Proposed Factory Complex Speed(K.P.H) Remarks 24900 85 Rural Area 24000 85 Rural Area 24500 85 Rural Area 25300 85 Rural Area 26300 85 Rural Area 27300 85 Rural Area 28300 85 Rural Area The data on the tables is from diagram 3 of the proposed factory upper and lower measurements. The Right hand side meridian edge is data on the first table is from the upper data measurements as will be when one is facing the proposed factory. When facing the factory the upper part of the road is ones right hand side. At the same time, when one is facing the factory the lower part of the road is ones left hand side. Thus the lower part is the left hand side median edge as on the second table. Vertical alignment diagram (i) Left hand side meridian side 19500 21250 23000 24750 26500 28250 30 000 (ii) Right hand side meridian side 28300 27300 26300 25300 24500 24000 24900 Brief Report A concentric scheme is used to reduce the land acquisition challenges considering the land may not be properly acquired. In this way, it is the future of the proposed factory complex is safe regarded. The two tables above show the chain age wise improvements on the proposed project road. The road construction in the right manner is vital as the proposed factory will rely on it as transport means. [d] The developer is expecting to use gullies to drain the new section of road and wants to know where the drainage outfall is likely to be. Write a letter to the developer comparing and contrasting the various drainage options for highway drainage, providing fully annotated sketches. Make fully reasoned recommendations about which would be the most appropriate options for the scheme, including a plan showing clearly where the different options have been used, and how the rain water will be discharged to suitable outfalls without flooding any of the surrounding area. Response to (d) Mr Gordon Henderson, Property Manager, Industrial Development Ltd, Greenfield House, Newlands Village, Hillington, H2 6DS. Tel: 0103 845234. Dear Sir, Re: Comparison and contrast of the various drainage options I am the Site Engineer of the proposed factory complex and i would like to present to you my work of comparing and contrasting the various drainage options of the high way drainage. The following are the provisions of drainage provided: (i) Covered line drainage in the rural setting. This type has cover from soil and Vegetation. This makes it safe for the road users as there is no possibility of landing in the drainage. This reduces the plant debris that fall on the drainage from blocking the drainage. Where water flows inside the drainage established in any set direction (ii) Open Chute drain found on slopes of high embankment. This is constructed on the slopes where it is hazardous and a particular care is required to safe regard the road users. In constructing open chute, the angle of the higher slope is cut thus increasing stability and preventing further slips. (iii) Road side earthen drains to capture surface run-off from the main road. This kind of drainage can be trapezium, rectangular or V- shaped. The disadvantage of this type is that it can accommodate little amount of water. It is also dangerous to the road users as it is risky for them to land on the drainage. The first option is recommendable as it has worked in many factories that are concerned about the safety of its workers. For example, the clothing factory where there is no much trouble in transporting the raw materials to the factories. It has also worked in several other factories in the rural setting. TASK 2 The Hillington local police Accident Investigation Unit are concerned that there have been a number of serious injury accidents at the location depicted in Diagram 4.Allan Bridge School Road Layout. Most of the accidents involve vehicles failing to negotiate the bend and overturning or running off the road into the gardens adjacent. The section of road is within a 30mph limit, although the road north of the school entrance is a derestricted single carriageway, and almost straight for over a mile. The existing geometric layout needs to be examined and the necessary actions need to be determined. Finance is available for land purchase where considerations are required. The following additional information should also be considered: - IP chain age is 950m The chain age of the first set of levels at the north end is 800m The design speed of the new alignment is to 50kph The radius of the new alignment shall be 180m The approach gradient from the north is +2% The departure gradient to the south is -1.79% [a] Determine the main factors that would appear to be causing the vehicles to lose control at this site. Report on how safety influences horizontal alignment and how circular curves are selected. Show any calculations for super elevation, and where it should be applied. Response to (a) Determine the main factors that would appear to be causing the vehicles to lose control at this site. There are sharp curves in need of improvement to provide a high speed. There is an absolute minimum radius of 100m at a location with a space constraint. Report on how safety influences horizontal alignment and how circular curves are selected. Safety influences safely aids in the resettlement/ rehabilitation of the location. To evade the challenge of the resettlement/ rehabilitation and acquisition existing alignment has been followed with restrictions on the designs. In this way the circular curves are selected or developed. The maximum length of the access road or street retains its status as a residential place. This length should ensure residential convenience rather than being unduly impaired as a result of speed restraints. The design of the speed and volume are such that they enable integration of pedestrian cycle and vehicular movements. Show any calculations for super elevation, and where it should be applied. Since the Chamber two up shaved shoulders are expected to be less than 7% as recommended the calculated super elevation will indicate whether it meets the recommendations set: S = V^2/2.828 * R Where S = Super elevation V = Design speed R = Radius So S = 50^2/2.828 * 0.18 = 159.12/100 = 1 59 % So it meets the recommendations set. The super elevation is applied on the up shaved shoulders. b] – Design the horizontal alignment and plot its position on the plan with any revised access to the school. Indicate super elevations, verge widths, surface water drainage, and areas of land purchase where required. Design of a suitable horizontal alignment Existing Chain age Existing Chain age Proposed Chain age Proposed Chain age Speed Remarks Start End Start End K.P.H 307/092 308/539 307/092 308/684 50 Urban Area 309/567 313/591 309/826 314/317 50 Urban Area 345/115 347/020 346/250 347/164 50 Urban Area The table shows the recommendations range of distance of curvatures in the rural (for example 308/567 is 308 t0 567 as the horizontal curvature range). This range goes in line with the set speeds. 15000 15970 17500 18500 20400 18900 18120 17950 17400 17220 16580 c] – Design the vertical alignment and plot it on a vertical section, showing the position of the components of the horizontal compound curve. The table shows the recommendations range of distance of curvatures in the rural (for example 308/539 is 308 t0 539 as the vertical curvature range). This range goes in line with the set speeds. Existing Chain age Existing Chain age Proposed Chain age Proposed Chain age Speed Remarks Start End Start End K.P.H 307/092 308/539 307/092 308/684 50 Urban Area 309/567 313/591 309/826 314/317 50 Urban Area 345/115 347/020 346/250 347/164 50 Urban Area Vertical alignment diagram with horizontal components (i) Upper part of the vertical alignment 17010 17430 20400 20000 19300 18500 18150 17450 17000 d] – Plot, to a suitable scale, cross-sections of the new carriageway at the 20m round chain ages, start and finish of the transition curves, and start and finish of the vertical curve. 15000 15970 17500 17010 18500 17430 20400 20400 20000 18900 19300 18120 18500 18150 19800 17450 17160 17000 17000 17400 17490 17220 17130 16580 17450 18150 18500 The above diagram shows the road carriage access at the 20 m round chain. The road has a capacity of pedestrians, vehicles and recreation with the traffic having the priority. This is the road design recommended to the Allan school as it can accommodate both the traffic and pedestrians safely. The transition vertical and horizontal curves are also included in the diagram. Show the recommended verge width and any cutting / embankment that may be necessary. The formula of getting verge is given by: V^2/R Where V is the specified speed and R is the radius of the curvature. So calculating the verge with the given V and R values, V = 50K.p.H And R = 180 m Verge = 50^2/180 = 13.89 m References ‘Feasibility Report for up-gradation of NH-65 ‘(2011). Km 30710 to 37710; Joodhupur-pali Road on BBFOT Basis. SAI Consultant Engineers Pvt. Ltd. Read More