LIFE CYCLE COST ANALYSIS WITH CONSTRAINED AND UNCONSTRAINED BUDGET FOR CITY ROAD NETWORK

Amrit pal Singh*, Tanuj Chopra***Engineer, PWD, Punjab**Assistant Professor, Department of Civil Engineering, Thapar University, Patiala. Punjab

ABSTRACT

The objective of this study is to develop a powerful system for the analysis of pavement management and investment strategies for the maintenance of the huge urban road network. The Highway Development and Management-4 (HDM-4) software has been used for strategy and program analysis of 10 road sections of Noida City. The HDM-4 tool provides the deterministic approach in data input and processing also utilizes data on existing road condition, traffic volume and composition to predict road deterioration as per the urban road conditions in terms of IRI value. HDM-4 simulates total life cycle conditions and costs for an analysis period under a user specified scenario of circumstances. A network economic evaluation is the most challenging use of the model, but the effort is well justified due to the potential savings on transportation costs achieved by comparing various alternatives and performing a budget constraint optimization. This study presents guidelines of HDM-4 analysis, reviews the applied methodology, input requirements and also shows future directions in order to apply HDM-4 effectively according to available urban conditions especially the mix traffic and the drainage conditions of the Noida city.

The methodology described here attempts to take advantage of all the capabilities of HDM-4, deal with the limitations of HDM-4, and produce usable results. The examples presented are actual HDM-4 inputs and results obtained from applying the model in many road stretches in the Noida city. The examples, which were selected from different evaluations performed on different roads to best illustrate a given evaluation step, do not otherwise reflect a particular pattern or relationship. The methodology used by the author calls for HDM-4 analysts to first identify the possible road works and then determine which road works to evaluate for each road class as a function of the traffic and other characteristics of the road class. For example, the works selected could be: (i) preventive treatment or surface treatment works for roads in good condition, (ii) surface treatment or asphalt concrete resurfacing works for roads in fair condition, and (iii) strengthening or reconstruction works for road in poor condition. It is important that the selected road works per road class be feasible from a purely technical point of view to produce realistic results.

HDM-4 allows for the definition of condition-responsive and scheduled project alternatives, for example, the maintenance schedule can be set up to execute an overlay when roughness reaches 4.0 IRI or execute an overlay every 15 years. However, under the proposed methodology, project alternatives are defined so that a given road work is scheduled in a given calendar year followed by a condition-responsive maintenance policy that keeps the road in good condition after the road work is executed. By defining the project alternatives this way, all possible combinations of road works and timing of road works are considered in the evaluation, making it easier to explore the corresponding results. Purely condition-responsive or scheduled project alternatives

(for example, executing overlay at 4.0 IRI or every 15 years) are not recommended because: (i) the interval between roads works should change over time due to the traffic growth; (ii) over an evaluation period, the same road works typically should not be repeated (for example, if one defines an alternative as 100 mm overlay when roughness reaches 4.0 IRI, the first overlay of 100 mm may be reasonable, but another overlay of 100 mm as a second capital work may be unreasonable); and (iii) the management of HDM-4 outputs is easier if one schedules the first road work in a given calendar year because the timing of the first road work can be coded on the project alternative code and name, making it easier to identify the solution of each road class.

The Pavement Management System methodology, developed in this study would be useful for the highway agencies in planning pavement maintenance strategies in a scientific manner and ensuring rational utilization of limited maintenance funds. Graphical presentations of PMS results will also be useful for gaining better support from decision-makers, for adequate and timely fund allocations for preservation of the highway network. This methodology may be used for preparing the maintenance management programme for the National Highways covered under the prestigious National Highway Development Programme (NHDP) of India. Once this PMS methodology for National Highway network is implemented and made operational for a few years; this would serve as a window to State Governments, particularly for State Highways and Major District Roads. Thereafter, similar kind of PMS may be developed for other categories of roads such as State Highways and Major District Roads, using the inputs of PMS methodology presented in this study.