Showing papers in "NCHRP Report in 1969"

Moving behavior and residential choice - a national survey

Abstract: INTERVIEWS WERE CONDUCTED OF A REPRESENTATIVE SAMPLE OF 1500 HOUSEHOLDS IN VARIOUS METROPOLITAN AREAS IN THE UNITED STATES TO DEVELOP LOGICAL RELATIONSHIPS FOR DESIRED HOME TYPE, PRICE RANGES, TRAVEL ACCESS MIXES, AND LIVING QUALITIES. A QUESTIONNAIRE WAS DEVELOPED FOR THIS PURPOSE BY THE UNIVERSITY OF NORTH CAROLINA WHICH WAS TO APPLY TO ALL URBAN AREAS IN THE UNITED STATES. THE SURVEY INSTRUMENT WAS CAREFULLY DESIGNED TO PROVIDE INFORMATION FOR TESTING SPECIFIC HYPOTHESIS ABOUT HOUSEHOLD BEHAVIOR, AS WELL AS PROVIDING A PROFILE OF CURRENT BEHAVIOR. INTERVIEWS, ABOUT ONE HOUR IN LENGTH, WERE CONDUCTED IN 43 METROPOLITAN AREAS ACROSS THE UNITED STATES. THE STUDY IDENTIFIES KEY VARIABLES UNDERLYING THE BEHAVIOR OF HOUSEHOLDS WITH RESPECT TO BOTH RESIDENTIAL MOBILITY AND RESIDENTIAL CHOICE. EMPHASIS IS PLACED ON THE MARGINAL CHANGE, THE INCREMENT OF ACTUAL HOUSEHOLD MOBILITY AND CHOICE IN A GIVEN TIME PERIOD, RATHER THAN ON CHANGE IN THE WHOLE RESIDENTIAL PATTERN. HOUSING PREFERENCES ARE STUDIED THROUGH ANALYSIS OF THE HOUSEHOLD'S ATTITUDES AND THEIR CHOICES IN THE HOUSING MARKET. IN ADDITION TO BUDGET AND FAMILY-SIZE FACTORS, THERE ARE A NUMBER OF ATTITUDINAL AND OTHER FACTORS WHICH HAVE A PRONOUNCED EFFECT ON THE WILLINGNESS OF URBAN HOUSEHOLDS TO MOVE AND ON THE WAY IN WHICH THEY MAKE HOUSING CHOICES. THE INTERVIEWS PROVIDED INFORMATION ON EACH HOUSEHOLD'S CURRENT AND PREVIOUS PLACE OF RESIDENCE, THE HOUSEHOLD'S CHOICE OF ITS CURRENT RESIDENCE, ACCESSIBILITY, OPPORTUNITIES, AND PREFERENCES OF THE HOUSEHOLD, DWELLING UNIT AND NEIGHBORHOOD PREFERENCES OF THE HOUSEHOLD, FUTURE MOVING INTENTIONS OF THE HOUSEHOLD, AND HOUSEHOLD ATTITUDES TOWARD FACTORS RELEVANT TO RESIDENTIAL MOBILITY AND HOUSING CHOICE. THE SURVEY INDICATES THAT IN RECENT INTRAMETROPOLITAN MOVES URBAN HOUSEHOLDS TEND TO SHIFT TOWARD OWNERSHIP, A SINGLE- FAMILY HOUSE, AND INCREASE IN NUMBER OF ROOMS, AND AN INCREASE IN HOUSING COST, THERE IS CONSIDERABLE VARIATION IN HOUSING PREFERENCES AMONG HOUSEHOLDS OF DIFFERENT SOCIO- ECONOMIC CHARACTERISTICS, AND WITH DIFFERENT RESIDENTIAL EXPERIENCE.

Identification of frost-susceptible particles in concrete aggregates

Abstract: AGGREGATE TEST METHODS TO IDENTIFY FROST-SUSCEPTIBLE PARTICLES IN CONCRETE AGGREGATES ARE EVALUATED. TWO APPROACHES TO THE PROBLEM OF IDENTIFYING FROST-SUSCEPTIBLE AGGREGATE PARTICLES WERE FOLLOWED. RELATIVELY HOMOGENEOUS AGGREGATE FRACTIONS WERE TESTED IN CONCRETE UNDER SIMULATED FIELD CONDITIONS, TO (1) DEVELOP A RATIONAL TEST METHOD INCORPORATING ELEMENTS OF FIELD EXPOSURE CONDITIONS, AND (2) ESTABLISH MEANINGFUL BASES OF AGGREGATE PERFORMANCE AGAINST WHICH OTHER TEST METHODS COULD BE COMPARED. THE SECOND APPROACH EXPLORED THE POTENTIALITIES OF SINGLE AGGREGATE PARTICLE TESTS AS SIMPLE, QUICK, AND ECONOMICAL MEANS OF IDENTIFYING FROST-SUSCEPTIBLE AGGREGATES. THE BASIC MECHANISMS OF FROST ACTION WERE ALSO INVESTIGATED. PETROLOGICAL STUDIES SUBJECTED THE AGGREGATES TO THREE FRACTIONATION PROCESSES TO OBTAIN RELATIVELY UNIFORM TEST FRACTIONS. RESEARCH CONCLUSIONS ARE THAT: (1) A RELIABLE QUANTITATIVE EVALUATION OF AGGREGATE FROST SUSCEPTIBILITY CAN BE ACHIEVED BY THE SLOW-COOLING METHOD, ORIGINALLY PROPOSED BY POWERS AND EXTENSIVELY INVESTIGATED, AND (2) THE MORE ECONOMICAL RAPID TEST METHODS YIELD RELATIVE RATINGS OF AGGREGATES WITH RESPECT TO FROST SUSCEPTIBILITY. THE SINGLE- PARTICLE TEST OF PERMEABILITY AND VOLUME CHANGE DURING COOLING IS THE MOST DISCRIMINATING OF THE RAPID METHODS STUDIED. VACUUM SATURATED ABSORPTION IS ONLY SLIGHTLY INFERIOR AS A BASIS FOR PERFORMANCE RATING. EXCEPT IN EXTREME CASES, RAPID TESTS ARE NOT LIKELY TO PROVIDE A SOUND BASIS FOR ACCEPTING OR CONDEMNING AGGREGATES WITH RESPECT TO THEIR FROST SUSCEPTIBILITY. IT IS RECOMMENDED THAT RESEARCH BE CONDUCTED TO DEVELOP ENVIRONMENTAL EXPOSURE INDICES. REFERENCES: IDENTIFICATION OF CONCRETE AGGREGATES EXHIBITING FROST SUSCEPTIBILITY, T. D. LARSON, A. BOETTCHER, P. D. CADY, M. FRANZEN, J. R. REED, NCHRP REPORT 15, 1965. A CRITICAL REVIEW OF LITERATURE TREATING METHODS OF IDENTIFYING AGGREGATES SUBJECT TO DESTRUCTIVE VOLUME CHANGE WHEN FROZEN IN CONCRETE, AND A PROPOSED PROGRAM OF RESEARCH, T. D. LARSON, P. D. CARY, M. FRANZEN, J. R. REED, HRB SPECIAL REPORT 80, 1964. AGGREGATE, THE DEGREE OF SATURATION AND THE PREVAILING ENVIRONMENTAL CONDITIONS ARE AS IMPORTANT AS THE DELETERIOUS CHARACTERISTICS OF THE AGGREGATE. RAPID TESTS ARE NOT LIKELY TO PROVIDE A SOUND BASIS FOR ACCEPTING OR CONDEMNING AGGREGATES WITH RESPECT TO THEIR FROST SUSCEPTIBILITY. THE QUESTION OF WHETHER THE AGGREGATE WILL PERFORM SATISFACTORILY UNDER SPECIFIED CONDITIONS IN THE FIELD MUST BE ANSWERED BY FIELD EXPERIENCE OR BY A LABORATORY TEST, SUCH AS THE SLOW-COOLING METHOD, THAT CLOSELY ASSIMULATES THE ANTICIPATED CONDITIONS OF FIELD EXPOSURE. PETROLOGICAL FRACTIONATION OF RAW AGGREGATE MATERIALS IS NECESSARY FOR MEANINGFUL EVALUATION OF FROST SUSCEPTIBILITY.

Highway noise measurement, simulation, and mixed reactions

Abstract: TWO MAJOR STUDIES FORMED THE BASIS FOR A THEORY OF TRAFFIC NOISE FROM WHICH A SIMULATION MODEL WAS BUILT, AND COMPUTERS WERE USED TO DESCRIBE THE NOISE OF DIFFERENT HIGHWAY SITUATIONS. THE TWO STUDIES BASIC TO THE SIMULATION MODEL INVOLVED COMPARING VARIOUS MEASURES OF SOUND, AND DECIDING UPON A SIMPLE, YET SATISFACTORY PHYSICAL MEASURE OF THE LEVEL OF SOUND, AND THEN MEASURING NOISE PRODUCED BY VARIOUS KINDS AND CLASSES OF VEHICLES. THE PHYSICAL MEASURE OF NOISE, SOUND LEVEL IN DECIBELS AS MEASURED ON THE A SCALE OF A STANDARD SOUND LEVEL METER, WAS SELECTED AS BEING STATISTICALLY INDISTINGUISHABLE FROM THE BEST PSYCHOLOGICALLY DERIVED MEASURES IN ITS RELIABILITY AS A PREDICTOR OF HUMAN RESPONSE TO VEHICLE NOISE. THE NOISE LEVEL RESULTS DESCRIBED ARE EXPRESSED IN TERMS OF THIS MEASURE, COMMONLY REFERRED TO AS "DBA." IN ADDITION TO THE MODEL, A DETAILED INTERVIEW WAS CONDUCTED WITH PEOPLE LIVING RELATIVELY NEAR A FREEWAY OR HIGHWAY. THESE INTERVIEWS FORM THE BASIS FOR PREDICTIONS ABOUT RESIDENTS' EXPRESSED ANNOYANCE WITH NOISE. NOISE FROM INDIVIDUAL MOTOR VEHICLES HAS TWO MAJOR COMPONENTS: ENGINE-EXHAUST, AND TIRE-ROADWAY INTERACTION. MOST MODERN PASSENGER CARS GENERATE AS MUCH NOISE BY TIRE-ROADWAY INTERACTION AS BY ENGINE-EXHAUST UNDER NORMAL OPERATING CONDITIONS. ACCELERATION, HOWEVER, PRODUCES MORE ENGINE-EXHAUST NOISE. LARGE DIESEL TRUCKS, SIGNIFICANTLY NOISIER THAN CARS, HOWEVER, REPRESENT A RELATIVELY SMALL PROPORTION OF TOTAL TRAFFIC ON URBAN HIGHWAYS. A LARGE DIESEL TRUCK-TRAILER COMBINATION IS EXPECTED TO PRODUCE 10 TO 15 DB HIGHER NOISE LEVELS THAN A PASSENGER CAR AT THE SAME ROAD SPEED DUE TO THE RELATIVE CONTACT AREAS OF THE TIRES WITH THE ROAD. INDICATIONS ARE THAT ATTEMPTS TO CONTROL VEHICLE NOISE BY OBJECTIVE NOISE LEVEL LEGISLATION HAVE NOT BEEN HIGHLY SUCCESSFUL. THE CONTROL OF NOISE THROUGH HIGHWAY PLANNING IS MORE LIKELY TO BE FRUITFUL THAN IS ENFORCEMENT OF VEHICLE LEVEL. SPECIFIC GUIDES ARE SET FORTH THAT WILL HELP STATE HIGHWAY DEPARTMENT ENGINEERS DETERMINE THE MOST APPROPRIATE MEANS AND UNITS FOR MEASURING AND EVALUATING HIGHWAY NOISE FOR A NUMBER OF COMMON TRAFFIC SITUATIONS. THESE GUIDES ARE PRESENTED IN TABULAR AND GRAPHIC FORM. THEY ARE SUPPLEMENTED BY A COMPUTER SIMULATION MODEL THAT ALLOWS THE ENGINEER TO PREDICT UNDER FIXED CONDITIONS OF VEHICLE SPEED, TRUCK MIX, VEHICULAR VOLUME, AND DISTANCE FROM THE HIGHWAY, THE VEHICLE NOISE LEVELS FOR ANY EXISTING OR PLANNING HIGHWAY SITUATION FOR FREELY FLOWING TRAFFIC.

Detecting seasonal changes in load-carrying capabilities of flexible pavements

Abstract: PROCEDURES ARE DESCRIBED FOR DETERMINING THE LOAD-CARRYING CAPABILITIES OF EXISTING FLEXIBLE PAVEMENTS IN AREAS SUBJECTED TO FROST ACTION. FIELD STUDIES WERE CONDUCTED TO: (1) EVALUATE EXISTING PROCEDURES, INCLUDING THOSE UTILIZING IMPULSE TECHNIQUES, (2) SELECT THE MOST PROMISING METHOD FOR DETERMINING THE LOAD-CARRYING CAPABILITIES OF FLEXIBLE PAVEMENTS DURING THE SPRING THAW PERIOD, AND (3) DEVELOP GUIDELINES FOR FIELD USE OF THE SELECTED METHOD. THE INITIAL EVALUATION OF EXISTING METHODS RESULTED IN SELECTION OF THE DYNAFLECT INSTRUMENT FOR FURTHER FIELD STUDY AND THE ULTIMATE DEVELOPMENT OF WARRANTS FOR IMPOSING LOAD RESTRICTIONS. THE DYNAFLECT EQUIPMENT MEASURES RESPONSES TO IMPULSE OR DYNAMIC LOADING. THE DYNAFLECT IS A TRAILER- MOUNTED DEVICE THAT LOADS THE PAVEMENT DYNAMICALLY AND INDICATES THE CORRESPONDING DEFLECTION AT SEVERAL POINTS ON THE SURFACE. IT IS ONE-MAN OPERATED AND TOWED BY A PASSENGER CAR. TESTS WERE MADE ON PAVEMENTS AT LOCATIONS RANGING FROM SPRINGFIELD, ILLINOIS NORTH TO DULUTH, MINNESOTA. THE TESTS SHOW THAT THE ANNUAL STRENGTH HISTORY OF PAVEMENTS IN NORTHERN CLIMATES IS DIVISIBLE INTO FOUR DISTINCT PERIODS: (1) A PERIOD OF DEEP FROST AND HIGH STRENGTH, (2) A PERIOD OF RAPID STRENGTH LOSS, (3) A PERIOD OF RAPID STRENGTH RECOVER, AND (4) A PERIOD OF SLOW STRENGTH RECOVERY. THE SECOND AND THIRD PERIODS TOGETHER CONSTITUTE THE CRITICAL PERIOD FOR FLEXIBLE PAVEMENTS. A SERIES OF CORRELATION STUDIES INDICATED THAT DYNAFLECT MEASUREMENTS COULD BE USED WITH REASONABLE ACCURACY TO PREDICT THE RESULTS OF PLATE BEARING TESTS AND BENKELMAN BEAM DEFLECTION TESTS, AS WELL AS THE CURVATURE OF THE PAVEMENT IN THE VICINITY OF A HEAVY WHEEL LOAD. THE OVER-ALL EFFICIENCY OF THE DYNAFLECT WAS JUDGED PRIMARILY ON THE BASIS OF ACCURACY, ECONOMY, AND NON- DESTRUCTIVE NATURE OF THE TESTING. THE RESEARCH RESULTS IN SUGGESTED WARRANTS, BASED ON THE USE OF THE DYNAFLECT, FOR DECIDING WHEN, WHERE, AND HOW LONG TO IMPOSE REDUCED LOAD LIMITS.

Improved criteria for traffic signal systems on urban arterials

Abstract: RESEARCH WAS CONDUCTED ON THE DEVELOPMENT AND COMPREHENSIVE, CLOSELY CONTROLLED, SCIENTIFIC TESTING OF SEVERAL ADVANCED CONCEPTS FOR OPERATING TRAFFIC-SIGNAL SYSTEMS ON URBAN ARTERIAL STREETS. THE RESULTS INDICATE THE DEGREE OF SIGNIFICANT IMPROVEMENT IN TRAFFIC OPERATION POSSIBLE THROUGH APPLICATION OF ADVANCED CONTROL METHODS. USING ESTABLISHED TRAFFIC-SIMULATION METHODS, A TOTAL OF 11 ALTERNATIVE SIGNAL-OPERATION TEST CONDITIONS IN A PILOT STUDY ARTERIAL SYSTEM WERE THOROUGHLY EVALUATED. SUBJECTED TO TESTS WERE FOUR STRATEGIC (FIXED-TIME) CONTROL CONCEPTS APPLIED IN VARIOUS COMBINATIONS, ONE TRAFFIC-ADJUSTED CONTROL CONCEPT, ONE EXPERIMENTAL TRAFFIC-RESPONSIVE CONCEPT, AND ONE SPECIAL MIXED-CYCLE VERSION OF A STRATEGIC CONTROL CONCEPT. A TOTAL OF 100 HOURS OF TRAFFIC OPERATION WERE SIMULATED TO PRODUCE STATISTICALLY RELIABLE RESULTS IN CONJUNCTION WITH THE EFFECTIVENESS TESTS OF ALTERNATIVES. THE MOST INFLUENTIAL STRATEGIC CONTROL CONCEPT TESTED WAS WEBSTER'S STRAIGHTFORWARD COMPUTATIONAL METHOD FOR OPTIMIZING TRAFFIC SIGNAL CYCLE AND SPLITS. THREE COMPUTER-ASSISTED METHODS FOR FORMULATING SIGNAL OFFSET PLANES WERE TESTED: THE YARDENI TIME-SPACE DESIGN MODEL, THE LITTLE MAXIMAL BANDWIDTH MODEL, AND THE DELAY/DIFFERENCE-OF-OFFSET METHOD. ALL THREE OFFSET METHODS PRODUCED STATISTICALLY SIGNIFICANT IMPROVEMENTS IN OPERATIONAL EFFECTIVENESS WHEN APPLIED IN COMBINATION WITH THE WEBSTER TECHNIQUE. HOWEVER, THE SAME THREE OFFSET CONCEPTS GENERALLY FAILED TO PRODUCE STATISTICALLY SIGNIFICANT IMPROVEMENTS WHEN APPLIED INDEPENDENTLY. THE RESEARCH INDICATED THAT THE TRAFFIC-ADJUSTED CONTROL CONCEPT, THE COMMONLY USED CYCLE AND OFFSET SELECTION MODE, REDUCES DELAYS IN THE PILOT SYSTEM BY 39% UNDER OFF-PEAK CONDITIONS AND BY 12% DURING A PEAK HOUR. THE EXPERIMENTAL TRAFFIC-RESPONSIVE CONTROL CONCEPT, THE BASIC QUEUE-CONTROL MODE TESTED IN PRIOR RESEARCH FOR ISOLATED INTERSECTIONS, PRODUCES 20% AND 22% REDUCTIONS IN DELAY DURING THE OFF-PEAK AND PEAK PERIODS, RESPECTIVELY, IN THE SIGNALIZED ARTERIAL SYSTEM. THE SPECIAL VERSION OF STRATEGIC (FIXED-TIME) CONTROL, THE MIXED-CYCLE MODE WHEREIN THE CYCLE LENGTH USED AT MINOR INTERSECTIONS IS SHORTER THAN THAT USED AT THE CRITICAL INTERSECTION, WAS THE MOST EFFECTIVE PEAK-PERIOD TECHNIQUE TESTED. TOTAL DELAY IN THE PILOT SYSTEM IS REDUCED BY 24% USING THIS METHOD DURING THE PEAK HOUR. RESEARCH RESULTS ALSO PRESENT INFORMATION THAT IS FUNDAMENTAL TO COST-BENEFIT ANALYSES OF MAJOR TRAFFIC-CONTROL IMPROVEMENT PROJECTS.

Development of design criteria for safer luminaire supports

Abstract: A LITERATURE REVIEW WAS CONDUCTED TO ESTABLISH THE STATE- OF-THE-ART IN SAFER LUMINAIRE SUPPORT CONSTRUCTION. IT WAS ESTABLISHED THAT, TO INSURE LOW IMPACT RESISTANCE, IT IS NECESSARY TO INCORPORATE A BASE WHICH WILL BREAKAWAY IN A COLLISION BUT WHICH POSSESSES SUFFICIENT STRENGTH TO RESIST STATIC AND WIND-INDUCED LOADS. THE FOUR BASIC CONCEPTS THAT HAVE BEEN DEVELOPED AND ARE ACCEPTED BY AT LEAST ONE STATE IN THE U. S. CAN BE BROADLY CLASSIFIED AS: (1) FRANGIBLE INSERT BASES, (2) PROGRESSIVE-CHAIR BASES, (3) ALUMINUM SHOE BASES, AND (4) SLIP JOINTS FULL-SCALE TESTS WERE CONDUCTED IN SUCH A MANNER THAT A COMPARATIVE EVALUATION COULD BE MADE OF THE FOUR BASIC CONCEPTS. THE FOLLOWING VARIATIONS OF THE BASIC CONCEPTS WERE ALSO TESTED AND EVALUATED: STAINLESS STEEL PROGRESSIVE-SHEAR BASE COUPLED WITH STAINLESS STEEL DAVIT AND MAST ARM TYPE SUPPORTS, AND A CAST ALUMINUM SHOE BASE WITH AN INTEGRAL RISER. ONE TEST WAS CONDUCTED ON A PRESTRESSED CONCRETE SUPPORT. THE COLLISIONS WERE PERFORMED WITH NOMINAL 3,500-LB. VEHICLES MOVING GENERALLY AT ABOUT 40 MPH. SEVERITY RATIOS AND A SEVERITY INDEX WERE CALCULATED FROM TEST DATA AND WERE USED TO RANK THE FOUR CONCEPTS TESTS FROM THE MOST SEVERE TO THE LEAST SEVERE, AS FOLLOWS: (1) ALUMINUM SHOE BASE WITH ALUMINUM SHAFT, (2) PROGRESSIVE- SHEAR BASE, (3) FRANGIBLE INSERT (ALUMINUM TRANSFORMER BASE), AND (4) THE TRIANGULAR SLIP JOINT. BASED ON THE RESPONSE OF DUMMIES IN THE VEHICLES, ALL COLLISIONS TESTED WERE JUDGED TO BE SAFE, WITH ONLY THE MOST SEVERE LIKELY TO PRODUCE MINOR OCCUPANT INJURY. A MATHEMATICAL MODEL WAS DEVELOPED THAT WAS USED TO STUDY THE VARIABLES THAT INFLUENCE THE COLLISION. RESEARCH CONCLUSIONS ARE THAT: (1) EXISTING FRANGIBLE INSERT (TRANSFORMER BASES) AND PROGRESSIVE-SHEAR BASES SHOULD BE OF SUCH HEIGHT AS TO ALLOW THE VEHICLE BUMPER TO CONTACT THEM, RATHER THAN THE LUMINAIRE SUPPORT SHAFT, (2) THE BASE FRACTURE ENERGY DETERMINED FROM LABORATORY IMPACT TESTS CAN BE USED AS A MEASURE OF ENERGY ABSORBED BY THE BASE IN A FULL-SCALE COLLISION, (3) WHERE THE PROBABILITY OF LOW-VELOCITY COLLISION IS HIGH WITH LUMINAIRE SUPPORTS, THE BASES SHOULD HAVE THE LOWEST POSSIBLE FRACTURE ENERGY AND THE SUPPORT POLE SHOULD BE CONSTRUCTED OF LIGHTWEIGHT MATERIALS, (4) A COLLISION SPEED OF ABOUT 35 MPH APPEARS TO BE THE LOWER LIMIT AT WHICH A CONVENTIONAL SUPPORT CAN BE EXPECTED TO CLEAR THE VEHICLE OR HIT BEHIND THE PASSENGER COMPARTMENT, (5) LARGE SUPPORTS WITH BASE FRACTURE ENERGIES IN EXCESS OF 9,000 FT-LB, SHOULD BE CONSIDERED WITH CAUTION BECAUSE LOW- VELOCITY COLLISIONS MAY BE SEVERE, AND (6) BREAKAWAY-TYPE BASES RESULT IN CONSIDERABLY LOWER AVERAGE ACCIDENT COSTS THAN DO THE MORE RIGID-TYPE BASES.

Economics of design standards for low-volume rural roads

Abstract: The objective of this study is to examine prevailing rural design standards to determine their economic justification. This would evaluate in depth the cost of some of the most significant design practices (for example, roadway and shoulder width and surfacing type). Resulting user benefits, such as operating, accident and time savings would be weighed against the cost of individual features. In addition to the analysis of the user-benefit relationships, the economic and social consequences to local residents, businesses and communities should be studies and a suitable means of including them in the reckoning of warranted levels of improvement should be found.

Evaluation of construction control procedures: aggregate gradation variations and effects

Abstract: FOUR INDIVIDUAL STUDIES CONCERNED WITH THE GRADATION OF AGGREGATES USED IN HIGHWAY CONSTRUCTION WERE CONDUCTED ON: (1) EFFECT OF VARIATIONS IN GRADATION OF COARSE AGGREGATE ON CHARACTERISTICS OF PORTLAND CEMENT CONCRETE. (2) VARIATION IN GRADATION OF AGGREGATES IN BITUMINOUS HOT-MIX PLANTS, (3) EFFECT OF INCREMENT SIZE ON SAMPLING ACCURACY, AND (4) MATHEMATICAL STUDY OF THE PATTERN OF VARIATIONS IN GRADATION OF AGGREGATES. A STATISTICALLY DESIGNED EXPERIMENT WAS USED TO DETERMINE THE EFFECT OF GRADATION VARIATIONS ON THE WORKABILITY AND COMPRESSIVE STRENGTH OF THE RESULTANT CONCRETE. INVESTIGATION WAS MADE OF VARIATIONS IN GRADATION OF BOTH FINE AND COARSE AGGREGATES AND ASPHALT CONTENTS AT SEVERAL POINTS IN THE PRODUCTION PROCESS OF BITUMINOUS HOT- MIX PLANTS. AN EXPERIMENT WAS CONDUCTED TO ESTABLISH THE PRACTICAL RELATIONSHIP BETWEEN MAXIMUM PARTICLE SIZE AND MINIMUM INCREMENT SIZE FOR DETERMINING THE GRADATION OF A LOT OF AGGREGATE. SEVERAL LOTS OF KNOWN GRADATION WERE PREPARED AND SAMPLED WITH SAMPLING SCOOPS OF PREDETERMINED CAPACITY. IT APPEARED THAT VARIATIONS IN THE GRADATION OF AGGREGATES FOLLOWED AN INHERENT PATTERN. DATA WERE ANALYZED TO DETERMINE THE POSSIBILITIES FOR SELECTING A SINGLE SIEVE FOR USE AS A QUICK CHECK ON COMPLIANCE WITH GRADATION SPECIFICATIONS. THE CONCRETE STUDY INDICATES THAT SAVINGS IN MANPOWER AND TESTING TIME CAN BE EFFECTED BY REDUCING THE SAMPLING FREQUENCY OF COARSE AGGREGATES FOR CONCRETE. THE MOST SIGNIFICANT FINDING WAS THAT COMPRESSIVE STRENGTH REMAINED SUBSTANTIALLY CONSTANT, REGARDLESS OF LARGE VARIATIONS IN THE GRADATION OF THE COARSE AGGREGATE, PROVIDED THE SLUMP WAS MAINTAINED AT A UNIFORM LEVEL. RESCREENING OR RESIZING COARSE AGGREGATES IS CONTRAINDICATED, AND IT IS RECOMMENDED THAT RESTRICTIVE GRADATION SPECIFICATIONS BE BROADENED TO ACCOMMODATE GRADATION VARIATIONS ACTUALLY FOUND TO EXIST. THE HOT-MIX BITUMINOUS PAVING PLANT STUDY FOUND THAT INDICATED VARIATIONS IN THE GRADATION OF BINNED AGGREGATES WERE LARGELY DUE TO WITHIN-BATCH VARIATION. IT IS RECOMMENDED THAT COMPLIANCE WITH JOB-MIX FORMULA GRADATION REQUIREMENTS BE BASED ON QUALITY HISTORY CHARTS RATHER THAN ON THE RESULTS OF INDIVIDUAL TESTS. THE USE OF USUAL SAMPLING TOOLS DOES NOT SEEM TO SERIOUSLY BIAS THE RESULTS. THE MATHEMATICAL STUDY CONFIRMED THAT THERE IS A TYPICAL PATTERN TO VARIATIONS OF AGGREGATE GRADATION. GRADATION SPECIFICATION SHOULD HAVE THE GREATEST TOLERANCE ON THOSE SIEVES THAT PASS 50 TO 70% OF THE AGGREGATE. THE REQUIRED SIZE OF TEST PORTIONS DEPENDS ON BOTH THE MAXIMUM PARTICLE SIZE AND THE GRADATION OF THE AGGREGATE.

One-cycle slow-freeze test for evaluations aggregate performance in frozen concrete

Abstract: INVESTIGATION WAS CONDUCTED TO DEVELOP A SIMPLE AND FAST TEST THAT COULD BE USED TO IDENTIFY AGGREGATES THAT CAUSE POOR CONCRETE PERFORMANCE WHEN FROZEN. A ONE-CYCLE SLOW- FREEZE TEST WAS DEVELOPED AND EVALUATED BY CORRELATING RESULTS WITH THE DURABILITY FACTOR OBTAINED FROM ASTM METHOD C290 (THE STANDARD FREEZING AND THAWING TEST IN WATER). THE ONE-CYCLE TEST INVOLVES FABRICATION OF 3 X16-INCH CONCRETE SPECIMENS USING AGGREGATES REPRESENTATIVE OF THE AGGREGATE SOURCE AND, AFTER 7-DAY CURING, PLACING THE SPECIMENS IN A CONVENTIONAL HOUSEHOLD DEEP FREEZE CHAMBER. STRAIN MEASUREMENTS ARE MADE WITH A WHITTEMORE STRAIN GAUGE AT 5- TO 15-MINUTE INTERVALS OVER A 4-HOUR COOLING PERIOD. FROM THE DATA COLLECTED, THE CUMULATIVE LENGTH CHANGE IS PLOTTED VS. TIME AND THE TIME SLOPE DETERMINED AS THE MINIMUM SLOPE THAT CAN BE FOUND WITHIN A 1/3-HOUR OR GREATER TIME RANGE. NINETEEN COARSE AGGREGATES FROM DIFFERENT PARTS OF THE COUNTRY AND REPRESENTING VARYING PERFORMANCE HISTORIES WERE USED TO FABIRCATE 336 SPECIMENS DURING THE EVALUATION PROGRAM. A SUFFICIENTLY STRONG RELATIONSHIP WAS FOUND BETWEEN THE TIME SLOPE AND THE DURABILITY FACTOR AT 100 FREEZE-THAW CYCLES TO INDICATE THAT THE ONE-CYCLE TEST COULD BE USED AS A SCREENING TEST WHERE THE DURABILITY FACTOR CAN BE CONSIDERED AS A MEASURE OF POTENTIAL FIELD PERFORMANCE. THE METHOD HAS THE ADVANTAGES OF SIMPLICITY, MINIMAL EQUIPMENT REQUIREMENTS, AND RELATIVE RAPIDITY. THE SIGNIFICANCE OF DURABILITY FACTOR IN RELATION TO FIELD PERFORMANCE MUST BE DETERMINED FOR A SPECIFIC AGGREGATE USE AND GEOGRAPHIC LOCATION. THE TEST METHOD AND TESTING PROCEDURES ARE PRESENTED IN DETAIL.

Evaluation of studded tires: performance data and pavement wear measurement

Abstract: THE CURRENT STATE OF KNOWLEDGE WITH BOTH STUDDED TIRE PERFORMANCE AND METHODS OF ASSESSING PAVEMENT WEAR IS REPORTED. AN ANNOTATED BIBLIOGRAPHY IS PRESENTED OF ALL KNOWN RESEARCH ON THIS SUBJECT FROM THE U. S. AND EUROPEAN SOURCES, A REVIEW AND EVALUATION OF THE DATA AND RESULTS OF COMPLETED STUDIES AND RECOMMENDATIONS FOR FUTURE RESEARCH. THE OBJECTIVES OF THE STUDY WERE CONFINED TO THE FOLLOWING TESTS: (1) CORRELATION OF DATA ON THE FRICTIONAL CHARACTERISTICS OF STUDDED TIRES ON ICE, PACKED SNOW, AND ON BARE PAVEMENTS, AND (2) DEVELOPMENT OF A METHOD, OR METHODS, OF QUANTITATIVE ASSESSMENT OF THE DIFFERENCE IN WEARING AND ABRASIVE EFFECTS OF STUDDED VERSUS UNSTUDDED TIRES ON DIFFERENT TYPES OF SURFACES. A STUD-RESISTANCE COEFFICIENT FOR OPERATION ON ICE WAS DERIVED AND ALL U. S. DATA ARE CORRELATED WITH THIS PARAMETER AND ICE TEMPERATURE. NO SIGNIFICANT LOSS OF BRAKING PERFORMANCE ON BARE PAVEMENTS IS INDICATED WITH LESS THAN 100 STUDS PER TIRE. STOPPING DISTANCE MIGHT BE INCREASED BY 10 PERCENT WITH 200 STUDS. METHODS FOR MEASURING WEAR AND PAVEMENT ROUGHNESS WERE INVESTIGATED. MATHEMATICAL RELATIONS BETWEEN THE VARIABLES WERE DEVELOPED WHICH CAN SERVE IN ARRIVING AT PREDICTIONS OF WEAR UNDER LOCAL TRAFFIC CONDITIONS.

Development of improved methods for reduction of traffic accidents

Abstract: A STATE OF THE ART REVIEW WAS CONDUCTED ON THE CURRENT PRACTICES OF ACCIDENT INVESTIGATION, REPORTING, AND ANALYSIS. THE SHORT COMINGS ARE DISCUSSED OF COMMONLY USED ACCIDENT RECORDS SYSTEM AND RECOMMENDATIONS MADE FOR SPECIFIC METHODS TO IMPROVE THESE SYSTEMS. A MULTI-LEVEL CONCEPT OF ACCIDENT INVESTIGATION IS PROPOSED WHICH INVOLVES THE BASIC REPORT OF ALL ACCIDENTS, LIMITED INVESTIGATION OF A SELECTED SAMPLE OF ACCIDENTS, AND INTENSIVE INVESTIGATION OF A LIMITED NUMBER OF ACCIDENTS. STUDIES OF ACCIDENT REPORT FORMS WERE INCLUDED IN THE RESEARCH TOGETHER WITH SUGGESTED METHODS FOR IMPROVEMENT. IMPLICIT IN THE PROPOSED SYSTEM IS THE NEED TO INTEGRATE ACCIDENT DATA WITH THE APPROPRIATE NONACCIDENT DATA: DRIVER, VEHICLE, AND HIGHWAY RECORDS. A SAFETY REVIEW BOARD IS RECOMMENDED FOR THE REVIEW OF ALL HIGHWAY PLANS AND PROGRAMS TO INSURE INCORPORATION OF CURRENT SAFETY KNOWLEDGE. A SIMPLIFIED ACCIDENT REPORT FORM IS NEEDED TO PROVIDE BASIC ACCIDENT DATA. AN APPENDIX INCLUDES SEVERAL DEMONSTRATION STUDIES THAT INDICATE THE TYPE OF INFORMATION THAT CAN BE OBTAINED BY USING AN IMPROVED ACCIDENT RECORD SYSTEMS STUDY. EXAMPLES INCLUDE TIRE FAILURE VERSUS VEHICLE SPEED, TIRE FAILURE VERSUS A NUMBER OF PLIES, FREQUENCY OF ACCIDENTS AS A FUNCTION OF TIME SINCE INSPECTION, FATAL ACCIDENT RATE BY SEX, ACCIDENT INVOLVEMENT ACCORDING TO VEHICLE MANUFACTURER, AND RELATIONSHIPS BETWEEN VEHICLE EXPOSURE AND ACCIDENTS. A NUMBER OF STUDIES CONDUCTED AS PART OF THIS PROJECT DEMONSTRATED THAT: (1) STATISTICAL ANALYSIS PERMITTED INTERPRETATION OF THE SIGNIFICANCE OF VARIOUS OBSERVATIONS, AND (2) PROPERLY TRAINED POLICE COULD COLLECT USEFUL AND RELIABLE INFORMATION.

Application of vehicle operating characteristics to geometric design and traffic conditions

Abstract: FIVE NATIONALLY USED REFERENCE BOOKS FOR HIGHWAY DESIGN AND TRAFFIC OPERATIONS PROCEDURES AND THREE TYPICAL STATE HIGHWAY MANUALS WERE REVIEWED TO DETERMINE WHERE PRACTICE MIGHT BE AFFECTED BY VEHICLE CHARACTERISTICS, PARTICULARLY AS THESE CHARACTERISTICS CHANGE WITH SUCCESSIVE DESIGNS OR ARE PERFORMANCE CAPABILITIES THAT ARE MODIFIED BY DRIVER PREFERENCE SINCE VEHICLE CHARACTERISTICS CHANGE OVER A PERIOD OF YEARS, A NEED WAS EXPRESSED TO UPDATE VEHICLE PERFORMANCE DATA FOR THE PURPOSE OF UPDATING DESIGN CRITERIA AND TRAFFIC OPERATIONS PROCEDURES HIGHWAY DESIGN CRITERIA AND TRAFFIC OPERATIONS PROCEDURES REQUIRE A KNOWLEDGE OF MOTOR VEHICLE CHARACTERISTICS ALL DESIGN AND OPERATING CHARACTERISTICS OF VEHICLES THAT INTERACT WITH THE HIGHWAY DESIGN AND TRAFFIC OPERATIONS PROCEDURES ARE LISTED AND DISCUSSED DETAILED DISCUSSIONS ARE PRESENTED OF ADDITIONAL CONSIDERATIONS THAT ARE FELT TO BE APPROPRIATE TO SOME GEOMETRIC STANDARDS AND OPERATING PROCEDURES NO STANDARDS OR PROCEDURES WERE FOUND TO EXIST IN WHICH CHANGES APPEARED TO BE MANDATORY BECAUSE OF CHANGES IN VEHICLES PRACTICALLY ALL OF THE RECOMMENDATIONS THAT HAVE BEEN MADE FOR RECONSIDERATION AND REVIEW, OR ESTABLISHMENT OF NEW STANDARDS, DERIVE FROM INCREASED TECHNICAL KNOWLEDGE CONCERNING THE RELATIONSHIP OF THE VEHICLE TO THE HIGHWAY AND TO TRAFFIC OPERATIONS STATISTICALLY DERIVED PROBABILITIES OF APPEARANCES ARE THE FOUNDATIONS FOR OTHER RECOMMENDATIONS AN EXAMPLE OF THE FIRST KIND IS THE TAKING INTO ACCOUNT FIELD OF VISION FROM THE VEHICLE WHEN DETERMINING CLEARANCE OF OBSTACLES AS A FACTOR IN LANE-WIDTH REQUIREMENTS AN EXAMPLE OF THE SECOND KIND IS THE DETERMINATION OF THE RELATIVE LIKELIHOOD AND CONSEQUENCES OF SKIDDING ON A CURVE WITH SUPERELEVATION, EITHER WHEN THE VEHICLE IS STOPPED ON AN ICY SURFACE OR SKIDS ON THAT SURFACE AS A RESULT OF EXCESSIVE CENTRIFUGAL FORCE DRIVER-MODIFIED PERFORMANCE CAPABILITIES OF VEHICLES LEAD TO STILL OTHER RECOMMENDATIONS TYPICAL EXAMPLES ARE: TAKING INTO ACCOUNT BODY-ROLL ANGLE WHEN DETERMINING MINIMUM RADIUS OF CURVATURE OF A HORIZONTAL CURVE BY THE BALL-BANK INDICATOR METHOD, AND THE SETTING OF THE LENGTH OF THE AMBER PHASE OF THE TRAFFIC SIGNAL, AS A FUNCTION OF APPROACH SPEED CONCLUSION IS MADE THAT MOST HIGHWAY DESIGN FEATURES AND TRAFFIC OPERATIONS PROCEDURES THAT RELATE TO VEHICLE CHARACTERISTICS ARE GOVERNED BY STANDARDS THAT ARE SATISFACTORY THE DETAILED INVESTIGATION OF HOW VEHICLE DESIGN CHARACTERISTICS RELATE TO HIGHWAY GEOMETRICS UNDERSCORES THE NEED FOR STABILIZING THE VEHICLE CHARACTERISTICS IT IS FELT THAT SOME VEHICLE DESIGN STANDARDS SHOULD BE IMPOSED ON THE INDUSTRY /AUTHOR/

Effect of highway landscape development on nearby property

Abstract: DATA WERE COLLECTED AND DISTURBANCES WERE MEASURED TO DETERMINE THE EFFECTS OF PHYSICAL DISTURBANCES BY LIMITED ACCESS HIGHWAYS ON NEARBY PROPERTY VALUES. THREE TYPE OF ANALYSES WERE MADE ON THE COLLECTED DATA: MAJOR-VARIABLE ANALYSIS, ECONOMIC ANALYSIS, AND INTERVIEW ANALYSIS. IN THE MAJOR-VARIABLE ANALYSIS, RELATIONSHIPS AND CORRELATIONS WERE EXAMINED BETWEEN SOUND LEVELS AND SOUND LEVEL REDUCTIONS AT SPECIFIC MEASUREMENT POINTS, AND OTHER VARIABLES SUCH AS SOUND LEVEL PERCEPTION, PRESENT TREE DIVERSITY, AND HOMEOWNERS' ATTITUDES OF BUYING ANOTHER HOUSE NEXT TO THE HIGHWAY. THE ECONOMIC ANALYSIS EVALUATED THE EFFECT OF HIGHWAY DISTURBANCES AND LANDSCAPE/LANDFORMS ON PROPERTY VALUES. THE INTERVIEW ANALYSIS WAS USED TO EVALUATE SPECIFIC COMPLAINTS OR DISTURBANCES. IN A SUPPLEMENTARY STUDY, FIELD EXPERIMENTS WERE CONDUCTED TO DEFINE RELATIONSHIPS BETWEEN SOUND LEVEL REDUCTION AND VARIOUS LANDSCAPING/LANDFORM CONFIGURATIONS AND DISTANCES, INCLUDING HIGHWAY ELEVATIONS, DEPRESSIONS, AND LANDSCAPING WITH TREES AND BUSHES. THE FINDINGS ARE PRESENTED AND REMEDIAL ACTIONS RECOMMENDED. IT IS THE OPINION OF THE RESEARCHERS THAT THE FINDINGS OF THIS STUDY HAVE THE MOST VALUE TO THE HIGHWAY ENGINEER IN SELECTING ROADWAY LANDFORMS AND IN SPECIFYING RIGHT-OF-WAY LANDSCAPING. HOWEVER, THE FINDINGS ARE ALSO OF VALUE TO A WIDE VARIETY OF PERSONS AND PRIVATE AND GOVERNMENT GROUPS. SPECIFIC POSSIBLE USES OF THE RESULTS BY THESE PERSONS AND GROUPS ARE SUMMARIZED.

Urban travel patterns for hospitals, universities, office buildings and capitols

Abstract: TRAVEL PATTERNS WERE STUDIED FOR HOSPITALS, COLLEGES AND UNIVERSITIES, OFFICE BUILDINGS, AND STATE CAPITOL COMPLEXES. THE ANALYSES INCLUDE TRIP GENERATION, TRIP DISTRIBUTION, AND GENERAL TRIP CHARACTERISTICS SUCH AS TRIP PURPOSE AND MODE OF TRAVEL. DATA WERE OBTAINED FROM MANY ORIGIN-AND-DESTINATION STUDIES CONDUCTED DURING RECENT YEARS FOR URBAN TRANSPORTATION PLANNING PROCESSES. TRIPS TO AND FROM SPECIFIC TYPES OF LAND USE WERE STUDIED. THE TRIP GENERATION CHARACTERISTICS ARE RELATED TO VARIOUS QUANTIFIABLE FACTORS FOR EACH SPECIFIC LAND USE THROUGH THE USE OF MULTIPLE REGRESSION ANALYSES. THE REGRESSION COEFFICIENTS AND THE STANDARD ERRORS DERIVED FROM THE MULTIPLE REGRESSION COMPUTATIONS ARE PRESENTED TO INDICATE THE VARIABILITY OF THE DATA INVOLVED AND THE RANGE OF CONFIDENCE THAT MAY BE PLACED IN USING THE REGRESSION EQUATION FOR PREDICTIVE PURPOSES. THE TRAFFIC GENERATION PREDICTION EQUATIONS DERIVED FROM THE MULTIPLE REGRESSION ANALYSES SHOULD PROVIDE THE TRANSPORTATION PLANNER AND TRAFFIC ANALYST WITH A TOOL WHEN HE MUST CONSIDER THE TRAFFIC EFFECTS WHICH WILL RESULT FROM A PROPOSED DEVELOPMENT OR EXPANSION OF AN EXISTING INSTITUTION.

Motorists' needs and services on interstate highways

Abstract: This report will be of primary interest to highway administrators and traffic planners who are concerned about the present and future service demands on the Interstate Highway System. This study compares the availability and the demand for (a) emergency services which are those normally supplied by police, tow vehicles and ambulances; (b) normal services which are routine services such as gasoline, food and lodging, and (c) supplemental services which include rest areas, signing for directions and services and a choice of service types, brands, prices, etc. Recommendations are presented which should remove some of the deficiencies found by the researchers.

Protective coatings for highway structural steel

Abstract: A CURRENT STATE-OF-THE-ART SURVEY IS PRESENTED WITH REGARD TO PAINTING OF HIGHWAY STRUCTURAL STEEL. A THOROUGH LITERATURE REVIEW WAS CONDUCTED AND AN INSPECTION AND EVALUATION MADE OF MORE THAN 4,000 PAINT EXPOSURE TESTS. PAINT FILM THICKNESS MEASUREMENT STUDIES WERE MADE. SPECIFIC RECOMMENDATIONS ARE GIVEN FOR SELECTING TYPICAL PAINT SYSTEMS ON THE BASIS OF SIX ENVIRONMENTAL ZONES, WHICH REPRESENT THE RANGE OF SEVERITY OF ENVIRONMENT IN WHICH HIGHWAY STEEL STRUCTURES ARE LOCATED IN THE UNITED STATES. MODEL SPECIFICATIONS ARE SUGGESTED FOR SURFACE PREPARATION, APPLICATION, MATERIAL PROCUREMENT, AND PAINT SYSTEM. ALTERNATE PAINT SYSTEMS WERE PROVEN FOR USE IN PLACE OF PRIMARY SYSTEMS IN EACH ZONE. THESE INCLUDE EPOXIES, CHLORINATED RUBBER, COAL TAR EPOXIES, SILICONE-ALKYD FINISH COATS, AND HIGH-BUILD COATINGS, AS PROVEN BY STEEL-PAINTING EXPERIENCE OF HIGHWAY DEPARTMENTS AND OTHER USERS. CRITERIA INFLUENCING THE CHOICE ARE DISCUSSED, INCLUDING COST, APPEARANCE, DESIGN, AVAILABLE MATERIALS, AND APPLICATION EXPERIENCE. COATINGS DISCUSSED WHICH DESERVE SPECIAL ATTENTION FOR HIGHWAY USE INCLUDE: WATER-BASE PAINTS, SOLVENT-FREE MATERIALS, COLORED ALUMINUM PAINTS, NON-LEAFING ALUMINUM INTERMEDIATE COAT, COLORED FINISH COATS, AND REFORMULATIONS MEETING AIR POLLUTION CONTROL REQUIREMENTS. CONDITIONS ARE ALSO INDICATED UNDER WHICH PAINTING MIGHT BE ELIMINATED IN FAVOR OF METALLIZING, GALVANIZING, GREASE-COATING, OR USE OF UNPAINTED STEEL. A RESUME IS PRESENTED OF THE BEST CURRENT PRACTICES OF THE HIGHWAY AND STEEL-PAINTING INDUSTRIES. ABOUT ONE-FIFTH OF THE STATES REQUIRE BLAST CLEANING, AND ANOTHER FIFTH ARE CONSIDERING IT. AIRLESS SPRAY, HOT SPRAY, AND ROLLER APPLICATION ARE PROVING EFFECTIVE, BUT MANY STATES REQUIRE BRUSHING OF PRIMER, PARTICULARLY OVER HAND-CLEANED STEEL. NEW PAINTS IN USE INCLUDE BASIC LEAD SILICO CHROMATE PIGMENTATION IN CONVENTIONAL VEHICLES, ZINC-RICH PAINTS (BOTH ORGANIC AND INORGANIC) WITH SUITABLE TOPCOATS, AND VINYL SYSTEMS FOR OTHER SEVERE EXPOSURES. THE MOST PRESSING PROBLEMS SEEM TO BE FILM THICKNESS, INSPECTION, PAINTING EDGES, POOR SPECIFICATIONS, DE-ICING SALTS, PAINTING BOLTED JOINTS, AND LACK OF OBJECTIVE TEST INFORMATION. THE STUDY SHOWED THAT SURFACE PREPARATION, PROPER APPLICATION, AND FILM THICKNESS ARE ALL MORE IMPORTANT THAN THE TYPE OF PAINT USED. THE PAINT THICKNESS MEASUREMENT SHOWED THAT: (1) A DIRECT CORRELATION EXISTS BETWEEN FILM THICKNESS AND PAINT LIFE, (2) SOME CURRENT PROCEDURES IN MEASURING DRY THICKNESS LEAD TO SERIOUS ERRORS, (3) THE USUAL METHOD OF MEASURING WET FILM THICKNESS IS MISLEADING, (4) THE HEIGHT OF BLAST-CLEANING PEAKS AND VALLEYS GREATLY AFFECTS THE AMOUNT OF PAINT NECESSARY TO ACHIEVE A GIVEN DRY FILM THICKNESS, AND (5) EACH OF THE SIX MOST COMMON THICKNESS GAGES HAS ITS OWN MERITS, BUT REQUIRES SPECIAL PRECAUTIONS IN USE.

Analytical study of weighing methods for highway vehicles in motion

Abstract: AN ANALYTICAL STUDY PROGRAM IS DESCRIBED FOR THE INVEST- IGATION OF ERROR ASSOCIATED WITH THE WEIGHING OF HIGHWAY VEHICLES IN MOTION, USING MULTI-PLATFORM ELECTRONIC SCALES PLACED IN THE HIGHWAY. THE ERROR ASSOCIATED WITH A WEIGHING SYSTEM COMES FROM TWO SOURCES: (1) THE ELECTRONIC EQUIPMENT FOR THE MEASUREMENT OF FORCE ON A HIGHWAY, AND THE PROCESS- ING OF DATA; AND (2) THE COMPUTATIONAL PROCEDURES EMPLOYED TO ASCERTAIN AXLE WEIGHT FROM THE SAMPLED FORCE DATA PROVID- ED BY THE PLATFORMS. THE VARIOUS DYNAMIC WAVEFORMS ASSOCIAT- ED WITH THE HIGHWAY VEHICLES WERE REVIEWED, AND SEVERAL COMPUTATIONAL PROCEDURES WERE EMPLOYED TO ASCERTAIN AXLE WEIGHTS FROM THE EXPECTED SAMPLED FORCE DATA WHICH WOULD BE PROVIDED BY A NUMBER OF PLATFORM TRANSDUCERS OR SCALES. THE INVESTIGATION OF COMPUTATIONAL METHODS FOR DETERMINING WEIGHT FROM THE SAMPLED FORCE DATA INCLUDED THE FOLLOWING: (1) DIRECT AVERAGING METHODS, WHEREBY THE FORCE OVER PLATFORMS WAS SIMPLY AVERAGED TO YIELD AN ESTIMATE OF AXLE WEIGHT, (2) DYNAMIC METHODS, WHEREBY AN ANALOGOUS MECHANICAL OSCILLATOR IS EMPLOYED TO FIT A SINE CURVE THROUGH THE OSCILLATING COMPONENT OF FORCE IN THE AVERAGE, (3) INTEGRAL MODEL III, WHEREBY A REGRESSION MODEL APPROXIMATING THE SECOND INTEGRAL OF AXLE FORCE WAS USED TO COMPUTE WEIGHT, AND (4) METHOD VWEIGH, AN AVERAGING PROCESS WHEREBY INTER- POLATION IS EMPLOYED TO YIELD A CONTINUOUS FORCE DATA RECORD. THE STUDY SHOWED THAT SIMPLE AVERAGING OVER THE PLATFORMS IS AN ECONOMICAL METHOD THAT CAN BE EMPLOYED, USING READILY AVAILABLE STANDARD EQUIPMENT AT A HIGHWAY SITE, WITH MAXIMUM ERROR GENERALLY LESS THAN 5 TO 6 PERCENT, DEPENDING ON VEHICLE OSCILLATION.

Protective coatings for highway structural steel. current highway practices

Abstract: A review was made of practices, specifications and experiences of the 50 state highway departments regarding painting highway structural steel. Interviews were conducted covering the following topics: paint life, costs, surface preparation, types of paint in use, most difficult problems, AASHO specifications and also included in tabulated form, current state specifications.