AUTOMATION IN PAVEMENT DESIGN AND MANAGEMENT SYSTEMS

EXISTING PAVEMENT DESIGN METHODS ARE GENERALLY BASED ON EMPIRICAL PROCEDURES AND USE MODELS THAT ARE BASED ON THEORY AND GENERAL EXPERIENCE. LITTLE ATTENTION IF ANY IS PAID TO ECONOMICS, ROUTINE MAINTENANCE, REHABILITATION, AND OTHER FACETS OF THE PAVEMENT LIFE CYCLE. WHEN THE OPTIMAL STRATEGY FOR A DESIGN PROCEDURE IS IMPLEMENTED, IT MAY PRODUCE RESULTS THAT DEVIATE FROM THOSE PREDICTED. FOR THIS REASON PAVEMENT DESIGN MUST INCLUDE A FEEDBACK CONTROL PROCESS THAT ACCUMULATES PAVEMENT DATA ON CONSTRUCTION, PERFORMANCE, AND COST IN A PAVEMENT SYSTEM DATA BANK THAT CAN BE USED TO MODIFY DESIGN SYSTEM MODELS. THE PRODUCT IS A CLOSED-LOOP PAVEMENT DESIGN AND MANAGEMENT SYSTEM. A FLOW CHART THAT INCLUDES CONTROL POINTS AND FEEDBACK LOOPS IS PRESENTED TO DISPLAY SYSTEM RELATIONSHIPS GRAPHICALLY. THE SOLUTION OF PAVEMENT DESIGN PROBLEMS VIEWED IN SUCH COMPLEXITY CANNOT BE UNDERTAKEN MANUALLY, BUT IN ADDITION TO OVERCOMING THIS DIFFICULTY THE COMPUTER AFFORDS GREATER FLEXIBILITY IN CONSIDERING ALTERNATIVES AND MAKING ITERATIONS. THE UNIVERSITY AND HIGHWAY DEPARTMENT OF TEXAS HAVE DEVELOPED A SET OF MODELS CALLED THE PAVEMENT DESIGN SYSTEM (PDS) WHOSE OPERATIONAL SYSTEMS CONSIST OF TWO TYPES OF COMPUTER PROGRAMS: A RIGID PAVEMENT SYSTEM (RPS) AND A FLEXIBLE PAVEMENT SYSTEM (FPS). BOTH SETS OF PROGRAMS ACCOUNT FOR THE ENTIRE PAVEMENT LIFE CYCLE. FUTURE COSTS ARE DISCOUNTED TO PRESENT VALUE. CONSTRAINTS ARE USED TO GENERATE SPECIFIC TYPES OF SOLUTIONS WITH RESPECT TO THICKNESSES, TIME SCHEDULES, AND FUNDS AND TO CONTROL THE NUMBER OF FEASIBLE DESIGNS. OTHER INPUTS ARE TRAFFIC, MATERIAL PROPERTIES AND COSTS, PERFORMANCE, ENVIRONMENT, ROAD GEOMETRICS, AND SEAL COAT SCHEDULING. FEASIBLE DESIGNS ARE ADVANCED TO POST- CONSTRUCTION ANALYSIS BY OPTIMIZING ROUTINES. A SAMPLE PROBLEM IS DESCRIBED IN WHICH EACH OF NINE PARAMETERS VARIES IN TURN WHILE THE OTHERS ARE HELD CONSTANT; OUTPUT IS OPTIMAL COST IN DOLLARS PER SQUARE YARD. THE SYSTEM ALSO PRODUCES COMPUTER PLOTS OF PROJECTED AND OBSERVED PERFOR- MANCE (INCLUDING MAINTENANCE), ANTICIPATED LIFE-CYCLE WORK SCHEDULES FOR A GIVEN PROJECT, AND LIFE-CYCLE WORK SCHEDULES FOR A HIGHWAY DISTRICT OR UNIT.