Preparation Stage Data Collection Data Analysis

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CHAPTER 3 METHODOLOGY

3.1 Overview

The methodology is a flow chart or structural steps to solve a problem with a scientific approach. Every completed step should be evaluated with great accuracy in order to produce results as expected.

3.2 Research Methodology

In general, this research is conducted in several stages, as seen in Figure 3.1. The detail of each stage is presented in the following sections.

3.2.1 Preparation Stage

Preparatory work includes activities such as literature review of previous related studies in road sector, review the theories about the design of road pavement, and develop a methodology of the research.

3.2.2 Data Collection

At this stage, all data related to this research were collected. This study only employed secondary data, which is consisted of • Traffic volume • Vehicle weight that overloading was occurred especially trucks. • Soil strength in terms of California Bearing Ratio CBR. • Thickness of existing pavement layers in Demak-Trengguli road section. • International roughness index IRI. 24 Figure 3.1: Methodology of This Study

3.2.3 Data Analysis

The secondary data obtained was analyzed on the basis of literature review and theories that had been learned. They are: 1 Existing physical conditions Preparation Data Analysis Secondary data Collection Literature Review Data traffic Pavement condition data Pavement structural number using 1993 AASHTO equation or nomograph Traffic volume and load data Roughness, M R and CBR Evaluation Evaluation Pavement thickness for design and actual traffic load The rest of road service life Average daily traffic ADT and vehicle damage factor VDF Start Conclusion and recommendation recommendation End 25 To know the existing physical condition, such as IRI, CBR, ADT obtained from Bina Marga. 2 Design condition Calculation of layer thickness using existing data was performed in order to know the differences between thickness of existing and design layers in Demak-Trengguli road section. The steps of calculation consist of: a. Determine the volume of traffic design ADT from survey data b. Calculate vehicle damage factor VDF c. Calculate cumulative equivalent single axle load CESAL using actual VDF based upon design and existing condition. d. Calculate pavement thickness based upon design and existing CBR and IRI. e. Calculate pavement service life for design and existing condition.

3.2.4 Evaluation