Highway Engineering - Assignment Example

Highway engineering The assignment looks into the design or redesign of the Road, route 352 which is in Delaware County, Pennsylvania. The starting coordinate is 39.915366, -75.424780 and the ending coordinate is 39.943339, -75.469283. The intersection that we are concerned about is 39.917538, -75.440315. The horizontal curves are located at 39.918723, -75.429414, 39.919908, -75.442976, and 39.932645, -75.448469. The highlight has been placed on the pavement design, roadside design and typical cross sections. Myriads of American roads demand expansion as the population growth has been experienced over years. At the same time, virtually all engineering projects have a timeline under which they should be operational on which if exceeded it is not appropriate (Mannering, Fred &Scott, 314). Pavement design Middletown road Route 352 pavement analysis and design examines the Growth Rate, Calculation and determination of the volume of traffic, ESAL, Reliability, Standard Deviation, Pi & Pt, Asphalt base, granular base and subcase. The pavement width is 12ft Fig1: Delaware annual average daily traffic (ADT) updated for November 2014 ESAL=fdxGrnxAADTix365xNixFEi Where ESAL=equivalent accumulated 18000 lb (80km) single axle load on an axle category i Fd=design lane factor (45%) Grn=growth factor in certain growth rate r and design period n (29.78) AADTi= first year annual average daily traffic for axle section (16000) Ni=axle number for each side of the vehicle (1, 2,3) FEi=load equivalency factor For passenger cars =0.00002 2 axle single unit trucks (26.7KN/axle)=0.010 3 axle single unit trucks (4.44 KN/axle) =0.088 For 2-axle single –unit trucks =0.45x29.78x16000x0.33x655x2x0.01 =5.1653x105 3-axle single –unit trucks =0.45x29.78x16000x0.17x365x3x0.0877 =3.5004x106 Total ESAL= (2-axle single –unit trucks) + (3-axle single –unit trucks) =5.1653x105+3.5004x106 =4.0169x106 According to Delaware annual average daily traffic (ADT) on latitude and longitude 39.915366, -75.424780 of the middle town road route 352, the there is an annual average daily traffic of 16000 as indicated on the map (Wright,Karen & Michael,342). Middletown route 352 has the proposal for the pavement structure and type B Pavement. It thus shares the characteristics of a medium to high volumes roads structure. It has a twenty-year designs of ESAL criteria exposing 100,000 to 20,000,000 units in the provided period. The proposed route design should have 75 to 150 mm typical asphalt concrete thickness (Wright,Karen & Michael,342). Fig 2: pavement structure type Fig on Cross sections of a typical pavement structure. The provided structure of layer thickness depends on the design EASL’s and groundwork conditions. Normally, the gravel roads apply the use of the high enhanced fines surfacing aggregate (SS 202) in the section of the running surface. This process is majorly applicable if the there is no graded aggregate seal coat applied. According to (Nicholas &Lester, 235), the asphalt base region requires an application of a mix of hot mix and graded aggregate seal coats. The proposed pavement and road design would have sandwiched asphalt pavement layers. The design and constructions take into care prevention of future drainage problems that emanate from trapping water in between the layers that can prompt acceleration of the structural destruction of the asphalt pavement stratum. This process causes heaving and reduces the structural strength of the road passage (Nicholas &Lester, 45). The selection of the Granular Sub-Base (SGSB) takes into consideration that its material typically entails of a 75mm in the absence of sand and gravel mixture. This material is either processed through screening or even crushing before drawing directly from an appropriate aggregate collection. Point. The selected Granular Sub-Base (SGSB) should not emanate from dredged river sand. Such sources are always Susceptible to pavement rutting. A deep analysis should be considered in case Dredged river sand is applied. The angularity of the collected materials and consideration of the previous output performance must come into place in case the use of the dredged granular base is inescapable. Furthermore, the applied sand should always remain dry to circumvent water seeping into the sand from the outlined embankment. While designing the pavement and road sections, SGSB may not be demanded or required in special l circumstances where the prevailing sub-grade material qualifies for the provided structural design criteria. Roadside design Roadside design for the route 352 middle town road should have at least the minimum requirement for the standard highway stipulations. It is highly recommended that Foot ways in the current construction stipulations should have a minimum of widths standards of 2000mm thus catering for the wide range of the user’s needs. Alongside the road, there are well exposed, and clear design sectors for the information for positioning of the long-term obstacles ensuring that footway width is well conserved. Provision of the 2000mm wide pavement allows for the prioritization of the pedestrians safety and provision and avoidance of temporary obstacles on the road (Wright,Karen & Michael,342). Fig3: twenty year period analysis GR-growth rate (%) = Traffic Growth rate= {((ADTf/ADTi) (1/(f-1)))-1} x100 ADTf=average daily traffic for future year (35000) ADTi=average daily traffic for year (16000) I=initial year for ADT (2013, year 1) F=future year for ADT (20 year) Traffic Growth rate= {((ADTf/ADTi) (1/ (f-1)))-1} x100 = {(35000/16000) (1/ (20-1)-1)} x100 =4.2% (Nicholas &Lester, 235). For a provided (analysis) period of twenty years, Middletown road route 352 roadside design and the pavement have a reliability (R) of 85% since it is a medium volume road. Delaware has other relatively high trafficked roads that range into traffic population of 4100. Middletown road route 352 is a Limited access and major arterial highway and has intersection at latitudes and longitude (39.917538, -75.440315). The standard deviation (So) for the road is at 4.9. The subcase shall constitute of a Crushed Base Course (CBC) The provision for the Limited access and major arterial highway demands at least depth of 300mm of Crushed Base Course case. On contrary, the Lower-volume segment of roads design Types C and D ritualistically demand a minimum depth of 225mm. Fig4: Middletown route 352 bend Pi & Pt. According to the fig 4, angle between point of curvature (pc) and point of tangent at point of intersection is 106 degrees. The bend is a sharp bend that demand an ample banking angle for the highway vehicle users. The point of road intersection (39.917538, -75.440315) demands slow down bounce as it poses a huge risk for the road users due to a combination of intersection and inherent bend notable at that point. Fig5: Middletown road route 352 cross-section at curve (39.918723, -75.429414) The cross section of the middle town road route 352 has ability to accommodate two bypassing vehicles. The subcase consists of crushed base course (CBC) which mainly entails the use of the well-graded base of 25 mm and a subsequent graded base 25 mm. The base has element of free draining, great support for the overlying masses and other strong factors. The subcase has course texture with a maximum nominal size of 50mm or 75mm and beyond. Subcase falls on the natural formation that is the intrinsic basement of a dug hollow. On top of the subcase lies the granular base that is slightly finer as compared to the subcase. It is sandwiched between the subcase and asphalt layer (Nicholas &Lester, 145). The proposed road has few obstructions and, therefore, has very few treatments needed in the course of construction. The intersection point at point Lima has congested outline around therefore demanding evacuation of residential home close by to facilitate construction of fly-overs in the future. The bend at point 39.917538, -75.440315 demands extension for the bend section to allow for inclusive and wide planning to allow to accommodate ample banking angle. In conclusion, the proposed improvement of the Middletown road route 352 is well established with inherent limitations and merits for the general completions of the process. According to the last period statistical estimations, there was 16000 ADTs on the road and indications that the road accommodates a very large number of people or road users. The road shows smooth outline except for the sections of the intersection and curving sections along the bends. The cross-section is mainly uniform with inclusive horizontal layers of subcase, granular, asphalt and other minor layers. Works cited www.dot7.state.pa.us/itms/default.asp Nicholas G., Lester H., Traffic and Highway Engineering, Technology & Engineering Civil Technology & Engineering / Civil / General Cengage Learning, 2014ISBN1305156242, 9781305156241,1248 . Wright, Paul H, Karen Dixon, and Michael Meyer. Highway Engineering. Hoboken, NJ: Wiley, 2003. Print. Mannering, Fred L, and Scott S. Washburn. Principles of Highway Engineering and Traffic Analysis. , 2013. Print. Safety Research on Highway Infrastructure and Operations: Improving Priorities, Coordination, and Quality. Washington, D.C: Transportation Research Board, 2008. Print. Read More