Single and Multi-Lane Road - Term Paper Example

ADVANCING OF THE A465 HEADS OF THE VALLEYS ROAD BETWEEN GILWERN AND BRYNMAWR FROM THE INITIAL SINGLE 3-LANE CARRIAGEWAY TO FINAL DUAL LANE CARRIAGEWAY STUDENT’ NAME CLASS INSTRUCTOR’S NAME NAME OF THE INSTITUTION: COURSE CITY DATE Table of Contents Table of Contents 1 Background Study 3 Single and multiple Lane 3 Dual Lane Carriageway 4 The A456 Heads of Valleys Road Project 4 Retaining Structures As used in the project 5 The Earth Retaining Structure 5 The Classification of the Earth Retaining Structures according to the Project 6 External Stabilization of the Structure 6 Internal Stabilization of the Structure 7 Type of Earth Retaining Wall to Considered in this Project 7 Aspects to be considered by the Construction before Deciding on the Best out of the Two Apparatus. 8 Lateral Earth Pressure 9 Pressure of the Earth While at Rest 10 Active Earth Pressure 10 Passive Earth Pressure 11 Designing of the Retaining Walls 12 Conclusion 12 Reference List 13 Background Study The A465 road was constructed back in the early years of 1960’s as a single-track road in the main the composition was of two lanes upward to the hill and down slope. By 1960, the researcher acknowledged the requirement of upgrading of the road. 34 years after advancements follow; there was the need to extend the road to about 40 kilometers between regions that required repair. When it reached 1995, Wales’s secretary informed state public of the need to improve the state of the road. Approaches were advanced, and an outline set up was formulated in 1997. The proof of the value and betterments made in 1997 and findings presented a resolution to continue the development in 1997. The completion would result in uninterrupted movement and would not only advance security but also develop system opt for by demolishing eight turning points. The project was a good strategy for the improvement of the head of the Valleys to best in 2020. The plan in construction outlook gives the best road outlook in the best smooth road considered as the final traffic flow bellow gives the free movement. Single and multiple Lane Lane carriageway schemes mean the improvement in the movement in and out of the road destinations. The road has attained the best-desired road in today’s condition as the eastward will be the little bit raised to a certain height about the pub site along the road. The intended land will estrange in a considerable resistant road with an aim of attaining Single three-lane carriageway system. To achieve this, a three lined road constructed in such a way that all the lines are within a lone highway and similarly, no existence of gap stipulation for a division that may hamper systemized vehicle movement is referred. The carriageway is also acknowledged as undivided highways because there are no central reservations alongside the road extend. In observing the preferred traffic flow, the roads are often designed and painted with different colors to create the distinction. The colors can be done either by solid or broken stretch marks or to some level amalgamation of the two parameters but with distinct design to notify the motorists when to join or leave another lane for the other one within the same carriageway. In Europe for example, the motorists keep midway part of the road as the overtaking path (Sze & Wong 2007) Dual Lane Carriageway This is double lane road that is constructed and allow the movement of two or vehicles moving in the opposite direction. In between the two roads, the design is the central separating mark allowing equal portions on both the road extend. The parameters are called dividing lines as they create the distinction in the line mark of the double lane. The modern developing and developed countries like the Dual Lane Carriageway system as they are the best and advanced traffic safety set up in comparison to the single lane highways. Consequently, some countries through their respective National Highway Authority departments have opted for high-speed limits for dual lane highways distinct from single lane carriageway (Hunt & Lyons 2010). More often than not, the track that is closer to the central parameter separating the two lanes is often preferred to be the inverted lane for overtaking other motorists along the highway. The A456 Heads of Valleys Road Project When the Welsh Government publicized the initiative to advance the double lane situations, the Government’s view was to advance the motorists movement to facilitate easier clearance of the site and sanction the land surveyors to carry out their inspection effectively. As stated by Mark Young, the best company’s construction manager allocated the tender to head the scheme, due to the preexisting environmental obstacles; part of the road had to be temporarily closed down more so during the weekend to facilitate thorough work in fixing the retaining structures more appropriately. Retaining Structures As used in the project Retaining structures are parameters appropriately planned to hold up the pressure exerted by the retained ground on top of other externally initiated masses during processes such as road construction and, therefore, transmitting these pressures to a particular base (Seed & Whitman, 2010). The improvement from a single three-lane carriageway to a lane dual carriageway, an earth retaining structure should be looked into, as it will be the suitable parameter applied to hold back the earth while retaining a sufficient disparity with the ground level. The approach should adopt for instance constructed in the 502 Brynmawr Junction Over the bridge, that is, the Gateway bridge to curtail chances of motorists or pedestrians falling off the bridge as it turned out off the accident. The Earth Retaining Structure As stated by Simpson (2012), the incurred expenses in installing a strong retaining wall emerged expensive, unlike one slope designing cost and steps for the period of a road diversion route. Taking from these facts, the Costain Construction Company through the highest construction managements under Mark Young should have an extensive preliminary scrutiny of the retaining wall they long to incorporate in the initiative. Within the phases of the construction process, they should strive to achieve the highest retaining wall with the least cost to minimize the cost of constructing the structure together with preceding maintenance costs realized at each interval in the structure located at the Brynmawr Junction with the bridge as well. The Classification of the Earth Retaining Structures according to the Project According to Underwood, Bowden, and Crundall, (2002), the construction mechanisms should stipulate filling up the retaining walls thereby holding up at the preferred height. In some places, for instance in the existing Brynmawr Roundabout broadening towards the factory as well as the Brynmawr bridge, the retaining wall should remain constant so that it is slightly higher to serve as an obstruction that may control motorists from rolling over but rather bounces back to the main in case of the accident. The adopted system worth this initiative should remain compact to uphold the wall as the road is ever busy with many motorists and passengers and in case the system considered in the construction process is weak, and then the likelihood of standing ages is obliged (Underwood et al., 2002). The eight sustenance aspects more so on Gateway Bridge should be more stable to reduce and keep on to the pressure that will be on timely basis exerted by the motorists as well as passengers using the highway at any given point. The perfect earth retaining structure blueprint in this specified initiative structurally should appear as, External Stabilization of the Structure Just illustrated above, on the outside-stabilized installations has the unmovable walls as well as the gravity walls. The unmovable wall can either be structural that is built or chemical. The structural walls are composts of the incise walls, bored piles that are often adjacent and con contiguous with tangent piles therein. The overall compound content that is cut wall, on the other hand, is made up of a blend of the deep soil and the jet grout. Subsequently, the chemical compounds and the outlook are normally braced with cross batch makers and anchored based on the injected pressure and build as well forming the constant wall of the structure under construction (Griffiths & Fenton 2013). Temporarily, the gravity wall is regularly a mixture of cast-in-place concrete and the modular gravity walls. The cast in place concrete are the cramped walls of the structure consisting of the buttress, counterfort, as well as the cantilever. On the contrary, the modular gravity is the filled wall that is compost of the bin, crib, concrete module and the stonework elements as well (Zeng & Steedman 2010). Internal Stabilization of the Structure Dissimilar to the external stabilization, the internal stabilization of the structure the internal stabilization of the retaining wall is made up of two apparatus, that is, stabilized mechanically and immovable support for the wall (Pellegrini & Salençon, 2009). The machine driven apparatus assimilates the fill walls made up of the metallic and polymeric strips for support and the sheets plus the grids. Also, there exist the reinforced soil slopes and the anchored earth to blended in coming up with the fill walls. At the same time, the in-situ reinforcements are the cut walls that ideally are compost of the mini and micro piles that are often reticulated as well as soil nailing. Type of Earth Retaining Wall to Considered in this Project Of attempts of upgrading the road to Head towards Valley Road from single lane to dual track, the Costain Construction Company preferably should go for gravity walls. Alternatively support earth walls as at some extent along the line they will require installing some durable and resistant structures more so close to the Brynmawr junction in which exists an over bridge. The gravity wall is always durable and resistance to breakage as they are made out of the shape. To serve the best way that improves their strength and enable them to bear up any load exerted on it at any time and likewise the reinforced earth walls are made from micro piles and soil nailed together (Richardson & Lee 2011). Aspects to be considered by the Construction before Deciding on the Best out of the Two Apparatus. The construction velocity: - The intended time to complete and finalize with the construction process while working out on the desired and appropriate retaining wall to put up. The gravity wall takes relatively longer to construct in comparison to reinforced wall because the solid elements need a reasonable period to strengthen and dry before the continuation of the construction process (Landva& Pelkey 2008). To achieve the road outlay to appear and achieve the resultant road shown in the diagram below Local contracting practices: - the choice to be made may be influenced by the subsequent local practices that the contractor engages. Thus, if the previous contractors chosen reinforced walls which in the long run has never been deemed suitable, the Company should consequently implement gravity wall in order to fetch the preferred changes in minimizing the road maintenance outlay (Landva& Pelkey 2008). Construction Considerations: - According to Landva and Pelkey (2008), because 11.5 km of the retaining structures needed in advancing the expansion of the road. The availability of the raw materials should be a basic requirement in constructing any given structure needed before settling on the best wall structure to construct or erect. Ground type: - the soil plays a valuable role in making a choice of the soil to construct the retaining structures. For example, regions of sandy soil prove to be weak and hence thorough assessments needs to be the first step taken before settling on the adequate measure to be adopted in the line of putting up the retaining wall (Landva& Pelkey 2008). Maintenance costs and durability and of the retaining structures: - as accepted by the Welsh Government in the process of tender acceptance, the constructor should always abide by the terms and conditions as specified by the Government. The government more often would prefer a permanent road with low maintenance costs than high valued (Landva& Pelkey 2008). Underlying rock strata water holding capacity: - under certain circumstances, the road track under construction may have poor water holding ability. Therefore, if a weaker retaining structure is constructed in such places, the possibility of the structure collapsing having taken few days as possible is very high. In that effect, the constructor needs to put into consideration establishing a very strong structure that can withstand the force imposed by such a position. (Landva& Pelkey 2008). Lateral Earth Pressure H validated the factors stated above, the expert building the two of A456 Heads valley road need to have in mind the three prerequisites of lateral earth pressure that are normally identified in the course of putting up the retaining structures at the time of road construction. Richardson & Lee (2011) Lateral pressure is the force that the soil tends to impose in the horizontal direction, to mean the relationships on the wall direction in case all changes direction. For example, as portrayed in the diagram moving towards the wall displays passive pressure, while moving outwards or remains in its position at the time as well. The study and the analysis of literal pressure are significant aspects as it influences the consolidated performance, and the ability of the soil to stand hence is always crucial aspect during the designing of the engineering structures like the retaining wall in the case of A465 Heads Valley Roads’ development. The constant of the horizontal force per area denoted K, can be described the value of the horizontal weight, represented as he divides by the vertical press vs. the absolute constraint is reached at by total pressure less the pole push evidenced in the earth process. The Coefficient of the lateral pressure of a given earth deposit mostly is measured as the moving characteristics and the related movement records of soil witnessed in that (Richardson & Lee 2011). In the structure retaining, that is, the wall is in situ and the material is in its natural state, the pressure that will be exerted in that by the outcome of eight is known as the earth pressure in the state of rest normally denoted by Po. Pressure of the Earth While at Rest This is commonly referred to as the pressure exerted by earth movement in the lateral dynamics. It is an important force per area unit as it moves the collection of soil in one place and useful factor in the design of engineering structures in the geotechnical engineering, for instance, deep foundations, basements, tunnels, retaining wall among others. The horizontal constant pull or push is denoted as K, presented as the total horizontal absolute σ’h, movement over the vertical constraint σ’v (Richardson & Lee, 2011). The least stable worth of K is called the active earth pressure coefficient, Ka; the active earth pressure is attained, such as, when a retaining wall drifts away from the soil. The ceiling stable value of K is referred to as inactive earth movement. Forces working in the vertical dimension and moving the debris laterally trigger the inactive earth movement. At rest, the ground value is at zero thus no pulls and push in either direction. The at rest pressure is expressed as KO = (Lateral Earth Pressure)/ (Vertically exerted pressure) Active Earth Pressure Active earth pressure is referred to as an experience in the state acceptable of the retained soil value causing changes in the earth nature or shape. During the times at which the soil moves away from the backfill, there tend to be diminishing the pressure on the wall, the process remains until the least value of strain reached such that there is no more decrease in the wall pressures hence all condition remain invariable. This is often denoted as Ka and is ideally constant at the total force exerted per area unit (Richardson & Lee 2011). The constant lateral value of force acted per unit area: when the retaining wall drifts away from underlying materials, the ratio exist therein between the flat acting unit force and the vertical direction because of the material placed above it is often known as constant force acting per unit volume. Ka = (Lateral Earth Pressure) / (Vertical Pressure) Passive Earth Pressure The inactive soil state is experienced when the casually is strained in the horizontal direction towards the earth debris until it knocks the maximum strain to counter the stress or destructions. It illustrates that the soil content may lose the strength and holds the soil to the initial flow. At times, there are situations when the retaining walls tend to move towards the backfill as had shown in the diagram above; this move eventually increases the pressure on the retaining walls. The process reoccurs until the higher value is achieved such that the pressure on the wall cannot enlarge any longer hence the state of the retaining wall stands unvarying. All these movement is due to pressure referred to as passive earth pressure and is often denoted as KP. The maximum coefficient value of earth pressure is deemed to be attained. (Richardson & Lee, 2011). The coefficient of the horizontal movements; whenever the constant concrete is moving towards materials lying above it, then the ratio between the horizontal force per unit area and the pressure pressed in the vertical direction as result of the weight of the material above it is known as the coefficient of the passive earth pressure KP = (Lateral Earth Pressure) / (Vertical Pressure) Consequently, various instances of horizontal earth moment, when the retaining wall is almost slipping due to the lateral push forced by the load therein, there is always a resistant force functional by the soil in the front of the retaining wall. Designing of the Retaining Walls As stated by Zeng & Steedman (2010), on completion of the pushing factors above, the construction is at liberty to design the process of retaining wall construction as approved best and free from predisposed factors of failure. The entire process should assimilate the following steps: Selection of the appropriate type of retaining wall; referring to the analysis done above, the Costain Construction Company should reach a consensus on the type of the retaining wall to construct, namely, be it gravity walls or the earth walls. The empirical process of determining the retaining wall, the contractor should take an appropriate measurement and decide on the correct dimension before the construction process. Estimate Earth Pressure; having analyzed the lateral earth pressures previously, the contractor will be in a pole situation to anticipate the probable pressures on the retaining wall to be put up. Estimation of the uplift forces; just like the lateral earth pressures, the contractor, should be noted down the uplifting forces to expect upon completion of the wall Estimation of the gravity forces; the construction is affected putting into consideration the eight of road users and the weight to be accommodated. Consideration of the external forces to be expected is put into consideration during the construction. Checking aspects to be considered while addressing chances of the wall sliding or overturning eventually Conclusion By putting into consideration of the above-discussed factors, the project stands a chance of being successful the anticipated outcome will be realized in the retaining wall construction. The ultimate attainment of the desired completion of A456 Heads of Valleys Road as desired by the Welsh Government through its regional traffic department shall result to one of the best Highways in the government of Wales ever since in history. Reference List De Buhan, P., Mangiavacchi, R., Nova, R., Pellegrini, G., & Salençon, J. 2009. Yield design of reinforced earth walls by a homogenization method. Géotechnique, 39(2), 189-201. Griffiths, D. V., & Fenton, G. A. 2013. Seepage beneath water retaining structures founded on spatially random soil. Geotechnique, 43(4), 577-587. Hunt, J. G., & Lyons, G. D. 2010. Modelling dual carriageway lane changing using neural networks. Transportation Research Part C: Emerging Technologies, 2(4), 231-245. Landva, A. O., Valsangkar, A. J., & Pelkey, S. G. (2008). Lateral earth pressure at rest and compressibility of municipal solid waste. Canadian Geotechnical Journal, 37(6), 1157-1165. Richardson, G. N., & Lee, K. L. 2011. Seismic design of reinforced earth walls. Journal of the geotechnical engineering division, 101(2), 167-188. Seed, H. B., & Whitman, R. V. 2010. Design of earth retaining structures for dynamic loads. In Lateral Stresses in the Ground and Design of Earth-Retaining Structures (pp. 103-147). ASCE. Simpson, B. (2012). Retaining structures: displacement and design. Géotechnique, 42(4), 541-576. Sze, N. N., & Wong, S. C. 2007. Diagnostic analysis of the logistic model for pedestrian injury severity in traffic crashes. Accident Analysis & Prevention, 39(6), 1267-1278. Underwood, G., Chapman, P., Bowden, K., & Crundall, D. 2002. Visual search while driving: skill and awareness during an inspection of the scene. Transportation Research Part F: Traffic Psychology and Behaviour, 5(2), 87-97. Zeng, X., & Steedman, R. S. 2010. Rotating block method for seismic displacement of gravity walls. Journal of Geotechnical and Geoenvironmental Engineering, 126(8), 709-717. Read More

The eight sustenance aspects more so on Gateway Bridge should be more stable to reduce and keep on to the pressure that will be on timely basis exerted by the motorists as well as passengers using the highway at any given point. The perfect earth retaining structure blueprint in this specified initiative structurally should appear as, External Stabilization of the Structure Just illustrated above, on the outside-stabilized installations has the unmovable walls as well as the gravity walls. The unmovable wall can either be structural that is built or chemical.

The structural walls are composts of the incise walls, bored piles that are often adjacent and con contiguous with tangent piles therein. The overall compound content that is cut wall, on the other hand, is made up of a blend of the deep soil and the jet grout. Subsequently, the chemical compounds and the outlook are normally braced with cross batch makers and anchored based on the injected pressure and build as well forming the constant wall of the structure under construction (Griffiths & Fenton 2013).

Temporarily, the gravity wall is regularly a mixture of cast-in-place concrete and the modular gravity walls. The cast in place concrete are the cramped walls of the structure consisting of the buttress, counterfort, as well as the cantilever. On the contrary, the modular gravity is the filled wall that is compost of the bin, crib, concrete module and the stonework elements as well (Zeng & Steedman 2010). Internal Stabilization of the Structure Dissimilar to the external stabilization, the internal stabilization of the structure the internal stabilization of the retaining wall is made up of two apparatus, that is, stabilized mechanically and immovable support for the wall (Pellegrini & Salençon, 2009).

The machine driven apparatus assimilates the fill walls made up of the metallic and polymeric strips for support and the sheets plus the grids. Also, there exist the reinforced soil slopes and the anchored earth to blended in coming up with the fill walls. At the same time, the in-situ reinforcements are the cut walls that ideally are compost of the mini and micro piles that are often reticulated as well as soil nailing. Type of Earth Retaining Wall to Considered in this Project Of attempts of upgrading the road to Head towards Valley Road from single lane to dual track, the Costain Construction Company preferably should go for gravity walls.

Alternatively support earth walls as at some extent along the line they will require installing some durable and resistant structures more so close to the Brynmawr junction in which exists an over bridge. The gravity wall is always durable and resistance to breakage as they are made out of the shape. To serve the best way that improves their strength and enable them to bear up any load exerted on it at any time and likewise the reinforced earth walls are made from micro piles and soil nailed together (Richardson & Lee 2011).

Aspects to be considered by the Construction before Deciding on the Best out of the Two Apparatus. The construction velocity: - The intended time to complete and finalize with the construction process while working out on the desired and appropriate retaining wall to put up. The gravity wall takes relatively longer to construct in comparison to reinforced wall because the solid elements need a reasonable period to strengthen and dry before the continuation of the construction process (Landva& Pelkey 2008).

To achieve the road outlay to appear and achieve the resultant road shown in the diagram below Local contracting practices: - the choice to be made may be influenced by the subsequent local practices that the contractor engages. Thus, if the previous contractors chosen reinforced walls which in the long run has never been deemed suitable, the Company should consequently implement gravity wall in order to fetch the preferred changes in minimizing the road maintenance outlay (Landva& Pelkey 2008).

Construction Considerations: - According to Landva and Pelkey (2008), because 11.

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