Factors to Consider When Designing an Abutment Bridge - Coursework Example

Construction of Abutment Name of the student Name of the Institution Date of submission Table of Contents Table of Contents 2 1.0 Introduction 3 2.0 ABUTMENT CONSTRUCTION 3 3.0 The following applies to the design and detailing of abutments and wingwalls 4 4.0 Factors to consider when designing an Abutment Bridge 4 4.1 Consider Retaining wall and the beam seat design 4 4.2 Considering the Stability 5 5.0 The work Breakdown Structure for the Construction of the Bridge Abutment 5 5.1 Activity Schedule and Duration & Labour Resource estimation 6 Project management 1.0 Introduction This paper provides an outline of typical construction methods and plant likely to be used for the main roadwork’s, structures including bridges, and ways to reduce the overall project time through manipulation of various variables. 2.0 ABUTMENT CONSTRUCTION Simac & Elton (2011) defines an abutment as a retaining structure normally designed and put up at the edge of a bride to act as support to the bridge. Abutments in most cases are necessary to act as resistant as well as transfer excess weight that may be caused by the lateral earth pressure. An abutment includes an end diaphragm, a stem wall and wingwalls. A stem wall or diaphragm functions as a wall providing lateral support for fill material on which the roadway rests immediately adjacent to the bridge. Abutments shall generally be of the cast-in-place, reinforced concrete type and shall be founded on spread footings, drilled shafts or driven pile footings (Simac & Elton 2011). Preferably, due to the ongoing projects at Toll Bar End, an abutment with a double pile foundation will be the most appropriate one considering the fact that the area has an A45 Stonebridge highway that is westbound between Toll bar and Stivichall and needs widening as from the Northern Kerb line (Dasenbrock et al., 2013). With the proposal of having an underpass linking A45 Stonebridge Highway to the A46 Coventry Eastern Bypass at Toll bar End junction, according to Helwany et al (2012), a retaining wall with abutments at both sides should be constructed in such a way that highway is able to withstand the pressure of the motorists plying the route especially next to the underpass structure. 3.0 The following applies to the design and detailing of abutments and wingwalls Granular Backfill: It follows the NDOT Standard Specifications for Road and Bridge Construction. Expansion Joints: Vertical expansion joints should be considered for wall lengths exceeding 125 ft in length. In this case, a water stop or other means of control shall be used to prevent leakage. Abutment Top Surfaces: Abutment seats at bearing locations shall be level. For seat abutments, the remaining exposed top surfaces shall be transversely sloped to provide adequate drainage. Approach Slab Seat: Provide a minimum 12-in approach-slab seat. Use restrainer units for all approach slabs that are not otherwise connected to the abutment or superstructure (Dasenbrock et al., 2013) 4.0 Factors to consider when designing an Abutment Bridge 4.1 Consider Retaining wall and the beam seat design The loads especially the backfill load which will be as a result of the pressure exerted by the external materials such as trucks will be calculated at –rest lateral earth pressure before the construction commences. Dasenbrock et al (2013) states that the limit state, which is the inability for the abutments to function, should be taken into consideration too during the construction of the abutment stem (wall). The limit state can either be an ultimate limit state or serviceability limit state. The ultimate limit state is whereby an abutment experiences distress and structural damage as a result of sliding, overall instability or overturning (Simac & Elton 2011). On the other hand, serviceability limit state is encountered when the abutment is unable to perform its intended design purpose fully due to too much deformation or deteriorations which may be caused by vibration, cracking or the lateral movement pressures. 4.2 Considering the Stability Determination of the critical reaction from the beam seat; It involves the calculation of the nominal loading on each 1m length of the abutment beam. Estimating the length of the back wall; this will depends on the recommended maximum height of the trucks and motor vehicles to use the underpass Estimation of the footing; the footing heel and toe depends on the width of the highway to be constructed (Simac & Elton 2011). 5.0 The work Breakdown Structure for the Construction of the Bridge Abutment The work break down structure is shown in the figure below (WBS) Estimation of the footing 5.1 Activity Schedule and Duration & Labour Resource estimation The construction of the bridge abutment in the A45 Stonebridge Highway will require a number of resources including casual labour, equipment and material supplies to be used in the process In estimation of required resources, three areas must be taken into consideration, these includes the inputs, tools and techniques as well as the anticipated output (Turner 2014). Input Methods & Tools Output Enterprise Environmental requirements Judgment of the Experts Duration of each activity estimate Firm process assets Analogous estimation Activity based updates Alignment of the project scope Parametric estimation List of construction activities Three-point estimates Activity based updates Reserve analysis Activity resource requirements Resource calendar Project management plan Preferably, duration estimates are often carried based on the fact that there are adequate resources to enable completion of the project in queue (Burke 2013). For instance, in the construction of the bridge apartment in the A45 Stonebridge Highway, all the necessary resources have been mobilized hence the project is expected to take 10 hours in every working day. The casual labors will be working 5 days in a week Determination of the limit States of the Bridge abutment Current Activity Previous Activity Duration Labour Earliest Started Date Determination of the critical reaction from the beam seat 10 100 02/11/2015 Estimating the length of the back wall Estimation of the footing Determination of the critical reaction from the beam seat Estimating the length of the back wall 7 10 70 100 16/11/2015 25/11/2015 Back fill load calculation at “at-rest” lateral earth pressure Estimation of the footing 7 70 09/12/2015 Determination of the limit States of the Bridge abutment Back fill load calculation at “at-rest” lateral earth pressure 5 50 04/01/2016 Setting up of the Abutment Structure Determination of the limit States of the Bridge abutment 5 50 11/01/2016 1.1 1.2 1.3 Path 1 2.1 2.2 2.3 Path 2 a) Five ways to Amend the Project (Attached-Gantt Chart-PM 2) b) New Completion Date (Attached-Gantt Chart-PM 2) When the shortest time period to complete a given activity: The time taken in every activity will have to be reduced so as to have enough time for the succeeding activities. The available work force can be combined so as to have a maximum output in one activity before proceeding to the next activity, that is, Project Manager A and B both pool their teams together to have one activity acted upon at once. The project managers can outsource some activities such as transportation of materials to the construction site in order to enable them get ample time to work on the necessary activities (Burke 2013). The team managers should hire or buy effective and enough working tools to enable the casual labors work with speed in order to complete the job within the shortest time possible. The project management should consider increasing the workforce based on the ground that the project owner is aware of the delay that the contractor was subjected to, prior to the project commencement. Using the work break down process, the project manager will be able to know how to manipulate different variables in order to come up with the most viable process to complete a given project. Bibliography Burke, R. (2013). Project management: planning and control techniques. New Jersey, USA. Dasenbrock, D., Budge, A., Field, B., & Mattison, D. (2013). Performance Monitoring Of A Bridge Abutment Spread Footing From Construction Through Service. Helwany, S., Ghorbanpoor, A., Alizadeh, V., & Oliva, M. (2012). A Novel Abutment Construction Technique for Rapid Bridge Construction: CLSM with Full-Height Concrete Panels (No. CFIRE 03-12). Simac, M. R., & Elton, D. J. (2011). Geosynthetic Reinforced Soil Walls as Integral Bridge Abutments. In Geosynthetics (Vol. 29, No. 2). Turner, J. R. (2014). The handbook of project-based management (Vol. 92). McGraw-hill. Read More