Sources of Cost Saving Opportunities in Highway Construction Quality Assurance Practices

Abstract

US transportation agencies are dealing with shrinking budgets, limited work forces, and deteriorating infrastructure. In order to cope with funding uncertainty, state highway agencies are now looking into their own organizations and identifying programs, practices, and processes that have potential for cost saving. A quality assurance (QA) program is an integral part of highway construction and ensures a project's contracted level of quality. The cost of quality (conforming and nonconforming) can constitute a sizable part of total construction cost. As the quality assurance programs evolved, various practices and processes were developed over time and later adopted by state highway agencies. These practices and processes include different QA standards and specifications, varying testing methods, central testing lab vs. on site testing, performance based vs. prescribed quality assurance practices, implementation of innovative quality assurance practices, etc. Therefore, there is an opportunity to assess different QA strategies and recommend those practices that are effective and cost efficient. A national survey was conducted by the authors, which provided a detailed mapping of various QA practices and processes used as part of QA programs and identified areas where agencies can focus on for cost savings. The survey found that QA sampling and testing plans, optimization of sampling plans, optimization of QA standards and specifications, and implementation of innovative test methods and processes are the main areas the agencies should focus to lean the current QA programs.

FIGURE I FOUR PRIMARY CAUSES OF CONSTRUCTION WORKER FATALITIES

FIGURE II EQUIPMENT MOVEMENT DIRECTION WHEN ACCIDENT OCCURS (N=594)

FIGURE III MAIN STEPS OF THE DEVELOPED HMM-BASED TRAJECTORYPREDICTION METHOD

FIGURE IV KEY ELEMENTS OF HMM PREDICTION MODEL

FIGURE V INPUT-PROCESS-OUTPUT DIAGRAM OF HMM TRAINING STAGE

FIGURE VI INPUT-PROCESS-OUTPUT DIAGRAM OF HMM PREDICTION STAGE

FIGURE VII VARIATION OF ANGULAR RISK FACTOR (α) NEAR THE HAZARD ZONE

FIGURE VIII LINEAR RISK FACTOR AND ADJUSTMENT OF PREDICTION

FIGURE IX HIGH-LEVEL FLOWCHART OF PCS2 MOBILE APPLICATION

FIGURE X SCREENSHOTS OF THE PCS2 MOBILE APPLICATION LAYOUTS

FIGURE XI FUNCTIONS USED FOR ALERT USERS FROM THEIR LOCATION DATA

FIGURE XII INITIAL INPUTS OF PCS2 FOR THE FIELD EXPERIMENT

TABLE I SHA FAILURES OBSERVED IN TEST RESULTS FOR DIFFERENT CONSTRUCTION TYPES/ MATERIALS

TABLE II SHAS’ USE OR EXPLORATION OF INNOVATIVE TESTING METHODS THAT REDUCE COST, SAVE TIME, OR PRODUCE MORE ACCURATE RESULTS