Benicia-Martinez Bridge ConstructionCIVIL ENGINEERING 165Professor MonteiroBrian Katz Erin LavigneYan-Ping Wang Jasmine KwakGroup MembersMap of Benicia Martinez BridgeOverview faced increasing congestion with commuter traffic  a cast-in-place balanced cantilever structure  approximately 8790 feet long and 83.5 feet wide  main span of the bridge (bridge length excluding approach spans) = 7435 feet long  span lengths between piers = 275.6 – 657.8 feet  vertical clearance > 141 feetStructure / PiersStructure / RebarBatching  Over 9000 batches produced, 61200 cy used for whole bridge On-site batching because cast in place adds times constraints. Also on-site is more economical for such a large amount of concrete needed  Weight of the mix had to be within 5% of the specific unit weight desiredWEIGHT TOLERANCES CONTROLLED FROM COMPUTERAggregate Cementious material Water ChemicalTolerance 1% 1% 1.5% volumeOn-Site BatchingOn-Site Batching PlantMineral Admixtures  Fly Ash From Tukwila, Washington Class F, low calcium Metakaolin Made from fine white clay called kaolin clays The clays are heated to 500-800 degrees C where they start to lose water through dehydroxilization.  Successful processing results in a disordered amorphous molecular structure, which is highly pozzolanic.Aggregates Stalite North Carolina Rotary kiln expanded slate Better in fires Allows spans to be longer and better performance in an earthquake There is so much rebar in the bridge that smaller maximum aggregate size had to be used Syar Lake Herman quarried 4 miles north of the bridge light weight  four miles from the construction so used to reduce cost  used for piers and pier tablesCement  Coarse Grind – larger particles, slower hydration reaction and lower heat of hydration Normal Grind – smaller particles, faster rate of hydration and strength development.Mix Specifications  Metakaolin= min 10% of cementious material (when less than 1% calcium oxide content by mass) Silica Fume= min 10% of cementious material Water = cannot change setting time by more than 25% cannot change mortar Compressive Strength (14days) by more than 5% With water reducing admixtures can reducecementious content up to 5%Lightweight Concrete Material Volume (ft3) SSD Weight (lb)Cement Type II-V, Normal Grind4.24 833Metakaolin, Powerpozz0.6 98ISG Resource – Flyash0.34 49Stalite ½” 9.02 858Hanson Sechelt Sand #17.64 1233Adva 100-Grace 50 OzWRDA 64-Grace 25 OzEclipse Floor-Grace 96 OzWater 4.87 304Air 0.4725Total 27.0 3375In retrospect, using a coarse grind cement instead may have helped lower the heat of hydration, but lab tests did not show a significant difference in heat of hydration between the two grinds.Cement Type II-V, Normal GrindLightweight Concrete used to achieve very high early and long-term strength in lightweight concrete. Cheaper, much easier to work with than Silica fume.Metakaolin, PowerpozzLightweight Concrete •The use of class F fly ash both reduces heat of hydration and increases workability •Metakaolin makes the concrete sticky and therefore harder to finish, fly ash helps with this•The presence of both fly ash andmetakaolin provides considerable protection against ASR ISG Resource – Flyash Lightweight Concrete state of the art, more expensivesuperplasticizer used to meet the demanding specs of the LW-9 Adva 100-GraceLightweight Concrete water reducing admixture, used in combination with superplasticizer to achieve desired slump. (Only so muchsuperplasticizer can be used before the concrete mix begins to segregate)WRDA 64-GraceLightweight Concrete the large amount of cementitious material used in LW-9 leads to a higher tendency for drying shrinkage. Eclipse is used to counteract drying shrinkage.Eclipse Floor-GraceLightweight Concrete thermally treated lightweight aggregate, allows for longer segmental bridge spans and earthquake resistance.Stalite ½”Lightweight ConcreteConcrete Mix for Piers- MIX 39SMaterial Volume (ft3) SSD Wt. (lb)Cement Type I-II, Coarse Grind2.65 521.00ISG Resource –Flyash1.21 174.00Syar Lake Herman ½”x#49.32 1571Hanson sand #1 9.21 1523Recover – Grace 36.47 ozADVA Flow – Grace 22 ozWater 4.07 253.68Air .54 0Total 27.00 4024.24quarry four miles away from job site, reduces transportation costsConcrete Mix for Piers- MIX 39SSyar Lake Herman ½”x#4set-retarding admixture, applied in variable dosages to different batches so that massive elements will remain workable throughout and then set all at once.Concrete Mix for Piers- MIX 39SRecover – Grace standard, more inexpensive superplasticizerConcrete Mix for Piers- MIX 39SADVA Flow - GraceConcrete Mix for Pier Tables - MIX 42SMaterial Volume (ft3) SSD Wt. (lb)Cement Type I-II, Coarse Grind3.05 600.00ISG Resource –Flyash1.39 200.00Syar Lake Herman ½”x#49.07 1528Hanson sand #1 9.10 1505Recover – Grace 19 ozADVA Flow – Grace 60 ozWater 3.85 240.05Air .54 0Total 27.00 4073.05- Very similar to mix 39S, except higher early and long-term strength is desired.- Lower w/c ratio, which in turn requires both more flyash to reduce the higher heat of hydration and more ADVA flow to further increase workability.Concrete Mix for Pier Tables - MIX 42SChemical AdmixturesConcrete Mix Comparison Lightweight concretePiers concrete Pier TablesConcreteSpecifiedCementious materialContent lb/cy674-1011 674-800 590-800Actual cementiousmaterial980 695 800% of Cementious :CementMetakaolinFly-ash (F)851057502575025C. Aggregate North Carolina StaliteSyar Lake Herman4 miles N. of bridgeSyar Lake Herman4 miles N. of bridgeWeight of cy 125 lbs. 150.85 lbs. 149.05 lbs.w/c ratio .31 .37 .30Strength Specified 45 MPa 35 MPa 45 MPaPour SiteGraph of Compressive Strength0102030405060010203040DAYSMIX 39 S LW-9 42 SDaysActual Strength (MPa)1 13 72 ----3 24 18 287 29.7 26 3714 33 4728 38.7 41 5135 42 55Temperature Control Assumptions made for the construction:  Average air temperature: 35-95°F Average concrete temperature: 40-80°F Maximum initial concrete temperature: 77°F Maximum temperature that aggregates and water can be heated: 65°CPost Cooling System either polyvinyl chloride or steel pipes  concrete temperature drop cannot