Highway Research Board bulletin最新文献

{"title":"LINE-HAUL TRUCKING COSTS IN RELATION TO VEHICLE GROSS WEIGHTS","authors":"H. Stevens","doi":"10.4271/620060","DOIUrl":"https://doi.org/10.4271/620060","url":null,"abstract":"A REPRESENTATIVE SCHEDULE IS PRESENTED OF VEHICULAR OPERATING COSTS. THE DIFFERENCES BETWEEN WHICH ARE CAUSED ONLY BY CHANGES IN VEHICLULAR GROSS WEIGHT, AND/OR CHANGES IN TYPES OF TRAILER COMBINATIONS. SUCH REPRESENTATIVE VEHICULAR COST DATA LATER CAN BE RELATED TO REPRESENTATIVE COSTS FOR HIGHWAY FACILITIES WITH DIFFERENT LOAD-CARRYING CAPABILITIES. THE REPORT DESCRIBES HOW THE DIFFERENT COST FACTORS WERE ADJUSTED FOR DIFFERENCES IN PRICES PAID FOR FUEL, WAGES, FRINGE BENEFITS, DEPRECIATION AND INTEREST CHARGES, AND NEW VEHICLES. THE DATA ARE PRESENTED IN AN EXTENSIVE SERIES OF CHARTS SHOWING THE VARIATIONS IN VEHICLE-MILE COSTS BY LOADED GROSS WEIGHT FOR ALL THE 23,384 TRAILER COMBINATIONS, ALL THE GASOLINE ENGINE POWERED TRAILER COMBINATIONS AND ALL THE DIESEL POWERED COMBINATIONS USING EITHER GASOLINE OR DIESEL ENGINES. OTHER CHARTS AND TABLES SHOW HOW UNIT COSTS ARE AFFECTED BY BODY TYPE, TYPE OF TERRAIN, AVERAGE DAILY TRAVEL MILEAGE, AVERAGE LOAD SPEED, AND OTHER OPERATING VARIABLES.","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1962-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79266719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forced vibration of continuous highway bridges","authors":"D. A. Linger, C. L. Hulsbos","doi":"10.31274/RTD-180813-636","DOIUrl":"https://doi.org/10.31274/RTD-180813-636","url":null,"abstract":"A CORRELATION IS PRESENTED OF FORCED VIBRATION THEORY WITH DYNAMIC IMPACT TESTS FOR THREE CONTINUOUS HIGHWAY BRIDGES AND A SIMPLE SPAN HIGHWAY BRIDGE. THE EXPERIMENTAL IMPACT WAS DETERMINED AT THE CENTERLINE OF THE SINGLE SPAN HIGHWAY BRIDGE AND IN THE OUTER AND INNER SPANS AND AT THE INTERIOR SUPPORTS FOR THE THREE TYPES OF CONTINUOUS FOUR-SPAN HIGHWAY BRIDGES. THE EFFECT OF THE VEHICLE IS ASSUMED TO BE AN OSCILLATING FORCING FUNCTION WHOSE FREQUENCY IS THE FREQUENCY OF AXLE REPETITION AND WHOSE FORCE IS THE OSCILLATING LOAD EFFECT OF A CONSTANT FORCE TRAVERSING A BEAM. THE CORRELATION OF THE THEORETICAL AND EXPERIMENTAL IMPACT INDICATES THAT THE SIMPLIFICATIONS MADE IN THE EFFECT OF THE VEHICLES ARE JUSTIFIED FOR THE BRIDGES TESTED AND THE EXPERIMENTAL VEHICLE VELOCITIES USED. THESE RESULTS SHOW QUALITATIVELY THAT THE AMOUNT OF IMPACT IS A FUNCTION OF THE RATIO OF THE FREQUENCY OF AXLE REPETITION TO THE LOADED NATURAL FREQUENCY OF THE STRUCTURE. /AUTHOR/","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"122 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1962-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80196910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EXPERIMENTAL PAVING PROJECTS USING CURTISS-WRIGHT'S COAL- MODIFIED, COAL-TAR BINDER","authors":"W. B. Drake","doi":"10.13023/KTC.RR.1962.173","DOIUrl":"https://doi.org/10.13023/KTC.RR.1962.173","url":null,"abstract":"THE OBSERVATION AND EVALUATION OF 13 SECTIONS OF EXPERIMENTAL PAVEMENT CONSTRUCTED IN KENTUCKY USING COAL- MODIFIED, COAL-TAR BINDER ARE DISCUSSED. THESE ARE COMPARED WITH THE PERFORMANCE OF CONTROL SECTIONS IN WHICH NORMAL SPECIFICATION ASPHALT CEMENTS WERE USED. THE RESULTS OF LABORATORY AND FIELD TESTS ARE ALSO REPORTED TO SUPPORT AND SUPPLEMENT THE VISUAL SURVEYS. /AUTHOR/","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1962-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85512862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A THEORY OF TRAFFIC FLOW FOR EVALUATION OF GEOMETRIC ASPECTS OF HIGHWAYS","authors":"M. Harr, G. A. Leonards","doi":"10.5703/1288284313592","DOIUrl":"https://doi.org/10.5703/1288284313592","url":null,"abstract":"AN ANALYTIC APPROACH IS DEVELOPED WHEREBY THE VARIOUS ASPECTS OF A HIGHWAY (SUCH AS CURVES, GRADES, LANE WIDTH, TRAFFIC CONTROL DEVICES, TYPE AND CONDITION OF SURFACING) CAN BE EVALUATED QUANTITATIVELY UNDER VARYING TRAFFIC DENSITY AND WEATHER CONDITIONS PROVIDING A RATIONAL BASIS FOR GEOMETRIC DESIGN. IN THE PRESENT ANALYSIS IT IS POSTULATED THAT TRAFFIC REACTS TO A MOTIVATING PRESSURE POTENTIAL IN A PATTERN THAT DETERMINES THE BEHAVIOR OF ANY PARTICULAR VEHICLE TRAVERSING A GIVEN SECTION OF ROADWAY. THIS CONCEPT CAN BE EXPRESSED QUANTITATIVELY IN A MANNER ANALOGOUS TO THAT USED IN DESCRIBING ONE-DIMENSIONAL VISCOUS FLOW IN A COMPRESSIBLE FLUID. SOLUTION OF THE RESULTING DIFFERENTIAL EQUATION YIELDS A PARAMETER WHICH IS A NUMERICAL MEASURE OF THE SALIENT CHARACTERISTICS OF A ROAD. PROCEDURES ARE THEN PROPOSED TO DETERMINE THIS PARAMETER, USING MEASURABLE VEHICULAR VELOCITIES, WHICH ELIMINATE THE NEED FOR EVALUATING THE MOTIVATING PRESSURE POTENTIAL.","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"6 1","pages":"87-91"},"PeriodicalIF":0.0,"publicationDate":"1962-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76560980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DRIVER RESPONSE TO AMBER PHASE OF TRAFFIC SIGNALS","authors":"P. L. Olson, R. Rothery","doi":"10.1287/OPRE.9.5.650","DOIUrl":"https://doi.org/10.1287/OPRE.9.5.650","url":null,"abstract":"OBSERVATIONS OF MOTORIST RESPONSE TO THE AMBER PHASE OF TRAFFIC SIGNALS OBTAINED AT FIVE INTERSECTIONS, REPRESENTING THREE SPEED ZONES, ARE PRESENTED. THE DATA GIVE AN ESTIMATE OF THE PROBABILITY OF STOPPING FOR VEHICLES AS A FUNCTION OF THEIR DISTANCE FROM THE INTERSECTION AT THE ONSET OF THE AMBER PHASE OF THE TRAFFIC SIGNAL. THE RESULTS LEAD NO SUPPORT TO A POPULAR HYPOTHESIS: THAT IS, THAT DRIVERS TEND TO TAKE ADVANTAGE OF A LONG AMBER PHASE BY TREATING IT AS AN EXTENSION OF THE GREEN. THE RESULTS OF THE STUDY ARE COMPARED WITH OTHER INVESTIGATIONS PERTAINING TO AMBER PHASE LENGTHS AND INPLICATIONS OF THIS WORK FOR THE DESIGN OF AMBER PHASES ARE DISCUSSED. /AUTHOR/","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"17 1","pages":"40-51"},"PeriodicalIF":0.0,"publicationDate":"1961-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78773678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Injury-producing private motor vehicle accidents among airmen","authors":"J. E. Barmack, D. E. Payne","doi":"10.1080/00223980.1961.9916500","DOIUrl":"https://doi.org/10.1080/00223980.1961.9916500","url":null,"abstract":"","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"147 1","pages":"1-22"},"PeriodicalIF":0.0,"publicationDate":"1961-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86662835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MEASUREMENT AND INTERPRETATION OF SURFACE VIBRATIONS ON SOIL AND ROADS","authors":"R. Jones","doi":"10.1088/0031-9112/11/8/001","DOIUrl":"https://doi.org/10.1088/0031-9112/11/8/001","url":null,"abstract":"THE ROAD RESEARCH LABORATORY IS DEVELOPING NONDESTRUCTIVE TECHNIQUES FOR MEASURING THE DYNAMIC MECHANICAL CHARACTERISTICS AND THICKNESSES OF THE LAYERS FORMING A ROAD. THE MATHEMATICAL THEORY FOR COMPUTING STRESSES AND DEFORMATIONS REQUIRES KNOWLEDGE OF THESE DATA AND THE DEVELOPMENT OF THESE TESTING TECHNIQUES IS A NECESSARY STEP TOWARDS A SYSTEM OF PAVEMENT DESIGN BASED ON THE STRESSES ENCOUNTERED IN THE ROAD AND THE MECHANICAL PROPERTIES OF THE MATERIALS. APART FROM THIS, THE TECHNIQUES ARE ALREADY ABLE TO PROVIDE INFORMATION OF IMMEDIATE VALUE IN THAT THEY PROVIDE DATA OF ASSISTANCE IN APPRAISING THE PERFORMANCE OF EXPERIMENTAL AND OTHER ROADS UNDER TRAFFIC, THEY CAN BE USED TO LOCATE AREAS WHERE VARIATIONS OF MECHANICAL PROPERTIES OR THICKNESS OCCUR, AND THEY CAN BE USED TO STUDY THE CHANGES PRODUCED BY TRAFFIC AND WEATHER. THE FIRST PART OF THIS PAPER DEALS WITH THE EXPERIMENTAL TECHNIQUE FOR MEASURING THE WAVE LENGTH AND PHASE VELOCITY OF MECHANICAL VIBRATIONS PROPAGATED ALONG THE SURFACE OF SOIL OR ROAD CONSTRUCTIONS. THE VIBRATIONS ARE PRODUCED ELECTRO-MECHANICALLY BY APPARATUS WORKING WITHIN THE FREQUENCY RANGE FROM 40 TO 60,000 C/S AND HAVE WAVE LENGTHS RANGING FROM A FEW INCHES TO SEVERAL FEET. THE RESULTS ARE NORMALLY EXPRESSED GRAPHICALLY AS THE RELATION BETWEEN PHASE VELOCITY AND THE WAVE LENGTH OBTAINED AT SELECTED FREQUENCIES. THIS CURVE HAS A NUMBER OF CHARACTERISTICS WHICH DEPEND ON THE ELASTIC PROPERTIES AND THE THICKNESSES OF DIFFERENT PARTS OF THE CONSTRUCTION: THE SECOND PART OF THE PAPER DISCUSSES THEORETICAL ANALYSES TO CALCULATE THESE PARAMETERS. SO FAR, MOST OF THE WORK HAS BEEN LIMITED TO EXPERIMENTAL CONSTRUCTIONS AND ALL THE RELEVANT DATA CONCERNING THICKNESSES AND TYPE OF MATERIAL HAVE BEEN KNOWN, WHILE VIBRATORY EXPERIMENTS HAVE ALSO BEEN MADE, WHERE NECESSARY, ON LABORATORY SPECIMENS OF THE MATERIALS TO DETERMINE THEIR ELASTIC PROPERTIES. THESE DATA HAVE ENABLED CHECKS TO BE MADE OF THE VALIDITY OF PREDICTIONS FROM THE VIBRATIONAL EXPERIMENTS. /AUTHOR/","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1960-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84889311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Study of Chert and Shale Gravel in Concrete","authors":"R. Schuster","doi":"10.5703/1288284314407","DOIUrl":"https://doi.org/10.5703/1288284314407","url":null,"abstract":"CERTAIN CHERT AND SHALE GRAVELS HAVE LONG BEEN RECOGNIZED AS HARMFUL WHEN INCLUDED IN PORTLAND CEMENT CONCRETE EXPOSED TO FREEZING AND THAWING. MANY ORGANIZATIONS HAVE SPECIFICATIONS LIMITING PERCENTAGES OF THESE MATERIALS IN CONCRETE AGGREGATES, BUT FEW OF THESE SPECIFICATIONS DISTINGUISH BETWEEN TYPES OF CHERT AND SHALE FROM DIFFERENT GEOGRAPHICAL AREAS NOR DO THEY ALWAYS TAKE INTO ACCOUNT THE BASIC PHYSICAL PROPERTIES OF THESE MATERIALS. IN THIS STUDY, PORE CHARACTERISTICS, MINERALOGY, TEXTURE, AND STRUCTURE WERE DETERMINED FOR CHERTS AND SHALES FROM NINE INDIANA GLACIAL GRAVEL DEPOSITS BY MEANS OF MICROSCOPIC PETROGRAPHY, X-RAY DIFFRACTION, AND THE COMMON SPECIFIC GRAVITY AND ABSORPTION TECHNIQUES. BLENDS OF 2, 4, 6, AND 10 PERCENT OF CHERT OR SHALE FROM EACH SOURCE WERE MADE WITH A STANDARD DURABLE CRUSHED LIMESTONE COARSE AGGREGATE, AND THESE BLENDS WERE USED IN 3- X 4- X 16-IN. AIR-ENTRAINED CONCRETE BEAMS SUBJECTED TO UP TO 300 CYCLES OF FREEZING AND THAWING. A MEASURE OF THE AMOUNT OF DEEP-SEATED DETERIORATION OF THE BEAMS WAS PROVIDED BY DURABILITY FACTORS CALCULATED FROM THE RESULTS OF NON-DESTRUCTIVE SONIC TESTING OF THE BEAMS AT INTERVALS DURING FREEZE-THAW TESTING. SEVERITY OF SURFACE DETERIORATION WAS ALSO EVALUATED. THE INFLUENCE OF THE BASIC PROPERTIES OF THE CHERT AND SHALE GRAVELS ON THE RESULTS OF THE FREEZE-THAW TESTS WAS THEN DETERMINED. ON THE BASIS OF THE RESULTS OF THESE TESTS, THE EXISTING SPECIFICATIONS ON CHERTS AND SHALES WERE STUDIED TO DETERMINE WHETHER THE SPECIFICATIONS REALISTICALLY CATEGORIZE THESE MATERIALS. DESPITE SIGNIFICANT DIFFERENCES IN THEIR MINERALOGIES, NO DIFFERENCE WAS NOTED IN THE FREEZE-THAW DURABILITIES OF THE VARIOUS CHERT SAMPLES. FOR ALL THE CHERTS, SIGNIFICANT DEEP- SEATED AND SURFACE DETERIORATION OCCURRED ONLY IN BEAMS CONTAINING 6 TO 10 PERCENT OF MATERIAL WITH A BULK SPECIFIC GRAVITY (SATURATED SURFACE-DRY BASIS) OF LESS THAN 2.45. ALTHOUGH THE BASIC PROPERTIES OF THE SHALES VARIED EVEN MORE WIDELY THAN THOSE OF THE CHERTS, NONE OF THE SHALES CAUSED DEEP-SEATED FAILURE OF THE CONCRETE. HOWEVER, THE MOST POROUS SHALES CAUSED POPOUT DAMAGE, WHICH WAS ESPECIALLY SEVERE AT THE 6 AND 10 PERCENT LEVELS. /AUTHOR/","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1960-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87495083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Engineering Soil Survey of Fayette County, Kentucky","authors":"R. Deen","doi":"10.13023/KTC.RR.1958.131","DOIUrl":"https://doi.org/10.13023/KTC.RR.1958.131","url":null,"abstract":"AGRICULTURAL SOIL SCIENTISTS HAVE DEVELOPED A SYSTEM OF SOIL CLASSIFICATION AND MAPPING THAT HAS BEEN AND IS CONTINUING TO BE OF GREAT VALUE TO THE SOILS ENGINEER IN RECONNAISSANCE AND MAPPING. THIS REPORT COVERS A STATISTICAL METHOD OF CORRELATION USED IN A PILOT STUDY CONDUCTED IN ORDER TO MAKE ENGINEERING SOILS DATA AVAILABLE FROM A PEDOLOGICAL MAP OF FAYETTE COUNTY, KY. ASSUMING THAT THE RELIABILITY OF PEDOLOGICAL CLASSIFICATIONS HOLDS TRUE FOR ENGINEERING PROPERTIES, THE ENGINEERING TEST CONSTANTS FOR A GIVEN HORIZON OF A GIVEN SOIL SHOULD FALL WITHIN A NARROW RANGE, AND THE LIMITS OF THIS RANGE SHOULD BE REASONABLY DETERMINABLE FROM THE RESULTS OF TESTS ON A SMALL NUMBER OF RANDOM SAMPLES. IN THE PRESENT STUDY A RANGE WITH A CONFIDENCE COEFFICIENT OF 0.90 WAS DETERMINED BY THE STATISTICAL METHOD USED. /AUTHOR/","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1959-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75785035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stresses and Deflections in Concrete Pavements Continuously Reinforced with Welded Wire Fabric","authors":"M. J. Gutzwiller, J. L. Waling","doi":"10.5703/1288284314391","DOIUrl":"https://doi.org/10.5703/1288284314391","url":null,"abstract":"LABORATORY EXPERIMENTS ON SIMULATED CONTINUOUSLY- REINFORCED CONCRETE SLABS ARE SUMMARIZED, WITH EXPERIMENTAL RESULTS PERTAINING TO SLAB DEFLECTIONS, CRACK WIDTHS, AND STRESSES IN WELDED WIRE FABRIC REINFORCEMENT. SOME OF THE SIGNIFICANT FINDINGS OF THESE LABORATORY EXPERIMENTS ARE COMPARED WITH FIELD OBSERVATIONS REPORTED IN THE LITERATURE AND SEVERAL CRITERIA ARE SUGGESTED FOR OPTIMUM STRUCTURAL DESIGN OF CONTINUOUSLY-REINFORCED PAVEMENTS. SOME OF THE CONCLUSIONS REACHED AS A RESULT OF THIS RESEARCH, SUBJECT TO THE LIMITATIONS IMPOSED BY THE RANGE OF VARIABLES STUDIED ARE: (1) IN ADEQUATELY-REINFORCED CONTINUOUS PAVEMENTS, TEMPERATURE DECREASES OF MORE THAN 30 DEG. BELOW CASTING TEMPERATURE TEND TO INCREASE THE DEFLECTIONS DUE TO VERTICAL (WHEEL) LOADS. TEMPERATURE DECREASES LESS THAN 30 DEG. TEND TOWARD A SLIGHT DECREASE IN DEFLECTIONS. (2) THE PERCENTAGE OF MID-DEPTH REINFORCEMENT HAS AN INFLUENCE ON MAXIMUM DEFLECTIONS DUE TO VERTICAL LOADS, BUT THE MAXIMUM DEFLECTIONS VARY SOMEWHAT INVERSELY WITH THE PERCENTAGE OF REINFORCEMENT. (3) UPPER SURFACE CRACK WIDTHS VARY LINEARLY WITH TEMPERATURE DECREASES IN SLABS INADEQUATELY REINFORCED WITH WELDED WIRE FABRIC BUT WITH ADEQUATE SPLICE LAPS. PAVEMENTS WITH ADEQUATE AMOUNTS OF REINFORCEMENT FORM NEW CRACKS DURING SIZABLE TEMPERATURE DECREASES AND OLD CRACKS DO NOT CONTINUE TO WIDEN IN DIRECT PROPORTION TO TEMPERATURE DROP. (4) MAXIMUM ACTIVE CRACK WIDTHS (DUE TO TEMPERATURE DROPS AND WHEEL LOADS) AT THE UPPER AND LOWER SURFACES OF THE SLAB CAN BE EQUALIZED AND MINIMIZED BY PROPER PLACEMENT OF THE STEEL REINFORCEMENT. LABORATORY EXPERIMENTS SUGGEST THAT TOP AND BOTTOM SURFACE ACTIVE CRACK WIDTHS MIGHT BE APPROXIMATELY EQUALIZED BY PLACEMENT OF THE FABRIC ABOUT 3/4 IN. BELOW MID-DEPTH. (5) AN INCREASE IN THE AVERAGE STEEL STRESS AT A CRACK ACCOMPANIES INCREASED TEMPERATURE DROPS (BELOW CONCRETE CASTING TEMPERATURE), FURTHERMORE THE STRESSES VARY INVERSELY WITH PERCENTAGE OF LONGITUDINAL REINFORCEMENT AT MID-DEPTH. (6) VERTICAL LOADS CONTRIBUTE SIGNIFICANTLY TO STRESSES IN THE REINFORCEMENT. (7) REINFORCEMENT PLACED 1-1/2 IN. ABOVE MID-DEPTH MUST RESIST STRESSES CONSIDERABLY GREATER THAN THE SAME AMOUNT OF REINFORCEMENT PLACED AT MID-DEPTH OR BELOW. /AUTHOR/","PeriodicalId":12918,"journal":{"name":"Highway Research Board bulletin","volume":"93 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1959-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80315984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}